MARYLAND DEPARTMENT OF THE ENVIRONMENT

1800 Washington Boulevard (	Baltimore MD  21230

410-537-3000  ( 1-800-633-6101

Cecil County, Maryland 

8-Hour Ozone

State Implementation Plan 

and Base Year Inventory

SIP Revision: 

07-05

June 15, 2007

Prepared for:

U.S. Environmental Protection Agency

Prepared by: 

Maryland Department of the Environment

This Page Left Intentionally Blank

TABLE OF CONTENTS

  TOC \o "1-3" \h \z    HYPERLINK \l "_Toc164568644"  1.0  Executive
Summary	  PAGEREF _Toc164568644 \h  8  

  HYPERLINK \l "_Toc164568645"  2.0  Introduction and Background	 
PAGEREF _Toc164568645 \h  12  

  HYPERLINK \l "_Toc164568646"  2.1  State Implementation Plans	 
PAGEREF _Toc164568646 \h  12  

  HYPERLINK \l "_Toc164568647"  2.2  Clean Air Act	  PAGEREF
_Toc164568647 \h  13  

  HYPERLINK \l "_Toc164568648"  2.3  SIP Requirements for Moderate
Nonattainment Areas	  PAGEREF _Toc164568648 \h  14  

  HYPERLINK \l "_Toc164568649"  2.4  Eight-Hour Ozone Standard	  PAGEREF
_Toc164568649 \h  15  

  HYPERLINK \l "_Toc164568650"  2.5  Ground Level Ozone	  PAGEREF
_Toc164568650 \h  15  

  HYPERLINK \l "_Toc164568651"  2.6  Air Pollution and the Chesapeake
Bay	  PAGEREF _Toc164568651 \h  16  

  HYPERLINK \l "_Toc164568652"  2.7  Health Effects	  PAGEREF
_Toc164568652 \h  17  

  HYPERLINK \l "_Toc164568653"  2.8  Maryland Specific Health Effects	 
PAGEREF _Toc164568653 \h  18  

  HYPERLINK \l "_Toc164568654"  2.9  The Impact of Ozone on Agriculture	
 PAGEREF _Toc164568654 \h  19  

  HYPERLINK \l "_Toc164568655"  2.10  The Air Quality Index (AQI)	 
PAGEREF _Toc164568655 \h  19  

  HYPERLINK \l "_Toc164568656"  2.11  Sources of Ozone Pollution in the
Cecil County Area	  PAGEREF _Toc164568656 \h  21  

  HYPERLINK \l "_Toc164568657"  2.12  Frequency of Violation of Federal
Health Standard for Ozone	  PAGEREF _Toc164568657 \h  23  

  HYPERLINK \l "_Toc164568658"  2.13  Required SIP Principles	  PAGEREF
_Toc164568658 \h  24  

  HYPERLINK \l "_Toc164568659"  2.14  Sanctions	  PAGEREF _Toc164568659
\h  25  

  HYPERLINK \l "_Toc164568660"  2.15  Reasonable Further Progress	 
PAGEREF _Toc164568660 \h  25  

  HYPERLINK \l "_Toc164568661"  2.16  Analysis of Reasonably Available
Control Measures (RACM)	  PAGEREF _Toc164568661 \h  25  

  HYPERLINK \l "_Toc164568662"  2.17  Contingency Measures	  PAGEREF
_Toc164568662 \h  26  

  HYPERLINK \l "_Toc164568663"  3.0  The 2002 Base-Year Inventory	 
PAGEREF _Toc164568663 \h  27  

  HYPERLINK \l "_Toc164568664"  3.1  Background and requirements	 
PAGEREF _Toc164568664 \h  27  

  HYPERLINK \l "_Toc164568665"  3.2  Total Emissions by Source	  PAGEREF
_Toc164568665 \h  28  

  HYPERLINK \l "_Toc164568666"  Point Sources	  PAGEREF _Toc164568666 \h
 28  

  HYPERLINK \l "_Toc164568667"  Quasi-Point Sources	  PAGEREF
_Toc164568667 \h  28  

  HYPERLINK \l "_Toc164568668"  Area Sources	  PAGEREF _Toc164568668 \h 
29  

  HYPERLINK \l "_Toc164568669"  Mobile Sources	  PAGEREF _Toc164568669
\h  29  

  HYPERLINK \l "_Toc164568670"  Nonroad Sources	  PAGEREF _Toc164568670
\h  31  

  HYPERLINK \l "_Toc164568671"  Biogenic Emissions	  PAGEREF
_Toc164568671 \h  32  

  HYPERLINK \l "_Toc164568672"  3.3 Emissions Trends	  PAGEREF
_Toc164568672 \h  32  

  HYPERLINK \l "_Toc164568673"  4.0  The 2008 and 2009 Projected
Inventories	  PAGEREF _Toc164568673 \h  36  

  HYPERLINK \l "_Toc164568674"  4.1  Growth Projection Methodology	 
PAGEREF _Toc164568674 \h  36  

  HYPERLINK \l "_Toc164568675"  Growth Projection Methodology for Point
Sources: EGAS	  PAGEREF _Toc164568675 \h  36  

  HYPERLINK \l "_Toc164568676"  Growth Projection Methodology for
Quasi-Point Sources	  PAGEREF _Toc164568676 \h  37  

  HYPERLINK \l "_Toc164568677"  Growth Projection Methodology: Area
Sources	  PAGEREF _Toc164568677 \h  37  

  HYPERLINK \l "_Toc164568678"  Growth Projection Methodology: Nonroad
Sources	  PAGEREF _Toc164568678 \h  39  

  HYPERLINK \l "_Toc164568679"  Growth Projection Methodology: Onroad
Sources	  PAGEREF _Toc164568679 \h  41  

  HYPERLINK \l "_Toc164568680"  Biogenic Emission Projections	  PAGEREF
_Toc164568680 \h  41  

  HYPERLINK \l "_Toc164568681"  4.2  Offset Provisions, Emission
Reduction Credits and Point Source Growth	  PAGEREF _Toc164568681 \h  41
 

  HYPERLINK \l "_Toc164568682"  4.3  Actual vs. Allowable Emissions in
Development of the 2008 and 2009 Projected Emissions Inventories	 
PAGEREF _Toc164568682 \h  43  

  HYPERLINK \l "_Toc164568683"  4.4  Projection Inventory Results	 
PAGEREF _Toc164568683 \h  44  

  HYPERLINK \l "_Toc164568684"  4.5  2008 Controlled Emissions for
Rate-of-Progress	  PAGEREF _Toc164568684 \h  44  

  HYPERLINK \l "_Toc164568685"  4.6  2009 Controlled Emissions for
Attainment	  PAGEREF _Toc164568685 \h  46  

  HYPERLINK \l "_Toc164568686"  5.0 2008 Reasonable Further Progress
Requirements	  PAGEREF _Toc164568686 \h  47  

  HYPERLINK \l "_Toc164568687"  5.1  Introduction	  PAGEREF
_Toc164568687 \h  47  

  HYPERLINK \l "_Toc164568688"  Rate of Progress Demonstrated in
Previous State Implementation Plans	  PAGEREF _Toc164568688 \h  47  

  HYPERLINK \l "_Toc164568689"  5.2  Guidance for Calculating Reasonable
Further Progress (RFP) Emission Target Levels	  PAGEREF _Toc164568689 \h
 48  

  HYPERLINK \l "_Toc164568690"  2008 VOC and NOx Target Levels	  PAGEREF
_Toc164568690 \h  49  

  HYPERLINK \l "_Toc164568691"  Calculation of 2008 Target Levels	 
PAGEREF _Toc164568691 \h  49  

  HYPERLINK \l "_Toc164568692"  5.3  Compliance with 2008 Reasonable
Further Progress Requirements	  PAGEREF _Toc164568692 \h  53  

  HYPERLINK \l "_Toc164568693"  6.0  Control Measures	  PAGEREF
_Toc164568693 \h  55  

  HYPERLINK \l "_Toc164568694"  6.1  1-Hour Ozone Control Measures	 
PAGEREF _Toc164568694 \h  55  

  HYPERLINK \l "_Toc164568695"  On-Road Mobile Measures	  PAGEREF
_Toc164568695 \h  55  

  HYPERLINK \l "_Toc164568696"  Area Source Measures	  PAGEREF
_Toc164568696 \h  57  

  HYPERLINK \l "_Toc164568697"  Non-Road Measures	  PAGEREF
_Toc164568697 \h  60  

  HYPERLINK \l "_Toc164568698"  Point Source Measures	  PAGEREF
_Toc164568698 \h  61  

  HYPERLINK \l "_Toc164568699"  6.2  8-Hour Ozone Control Measures	 
PAGEREF _Toc164568699 \h  63  

  HYPERLINK \l "_Toc164568700"  The Maryland Healthy Air Act (HAA)	 
PAGEREF _Toc164568700 \h  63  

  HYPERLINK \l "_Toc164568701"  Architectural and Industrial Maintenance
Coatings Rule	  PAGEREF _Toc164568701 \h  66  

  HYPERLINK \l "_Toc164568702"  Industrial Adhesives and Sealants Rule	 
PAGEREF _Toc164568702 \h  68  

  HYPERLINK \l "_Toc164568703"  Portable Fuel Containers Rule:  Phase II
  PAGEREF _Toc164568703 \h  68  

  HYPERLINK \l "_Toc164568704"  Consumer Products Rule:  Phase II	 
PAGEREF _Toc164568704 \h  69  

  HYPERLINK \l "_Toc164568705"  6.3  Voluntary and Innovative Measures	 
PAGEREF _Toc164568705 \h  70  

  HYPERLINK \l "_Toc164568706"  Regional Forest Canopy Program: 
Conservation, Restoration, and Expansion	  PAGEREF _Toc164568706 \h  71 


  HYPERLINK \l "_Toc164568707"  Clean Air Teleworking Initiative	 
PAGEREF _Toc164568707 \h  73  

  HYPERLINK \l "_Toc164568708"  High Electricity Demand Day (HEDD)
Initiative	  PAGEREF _Toc164568708 \h  78  

  HYPERLINK \l "_Toc164568709"  Emission Reductions from Transportation
Measures	  PAGEREF _Toc164568709 \h  78  

  HYPERLINK \l "_Toc164568710"  7.0  Reasonably Available Control
Measure (RACM) Analysis	  PAGEREF _Toc164568710 \h  81  

  HYPERLINK \l "_Toc164568711"  7.1 Analysis Overview and Criteria	 
PAGEREF _Toc164568711 \h  81  

  HYPERLINK \l "_Toc164568712"  Implementation Date	  PAGEREF
_Toc164568712 \h  82  

  HYPERLINK \l "_Toc164568713"  Enforceability	  PAGEREF _Toc164568713
\h  82  

  HYPERLINK \l "_Toc164568714"  Technological Feasibility	  PAGEREF
_Toc164568714 \h  83  

  HYPERLINK \l "_Toc164568715"  Economic Feasibility and Cost
Effectiveness	  PAGEREF _Toc164568715 \h  83  

  HYPERLINK \l "_Toc164568716"  Substantial and Widespread Adverse
Impacts	  PAGEREF _Toc164568716 \h  83  

  HYPERLINK \l "_Toc164568717"  De Minimis Threshold	  PAGEREF
_Toc164568717 \h  83  

  HYPERLINK \l "_Toc164568718"  Advancing Achievement of 84 ppb Standard
  PAGEREF _Toc164568718 \h  84  

  HYPERLINK \l "_Toc164568719"  Intensive and Costly Effort	  PAGEREF
_Toc164568719 \h  84  

  HYPERLINK \l "_Toc164568720"  7.2 RACM Measure Analysis	  PAGEREF
_Toc164568720 \h  84  

  HYPERLINK \l "_Toc164568721"  Analysis Methodology	  PAGEREF
_Toc164568721 \h  84  

  HYPERLINK \l "_Toc164568722"  Analysis Results	  PAGEREF _Toc164568722
\h  84  

  HYPERLINK \l "_Toc164568723"  7.3 RACM Determination	  PAGEREF
_Toc164568723 \h  84  

  HYPERLINK \l "_Toc164568724"  8.0 Mobile Source Conformity	  PAGEREF
_Toc164568724 \h  86  

  HYPERLINK \l "_Toc164568725"  8.1 Mobile Emissions Budget and the
Wilmington Region Transportation Conformity Process (includes Cecil
County)	  PAGEREF _Toc164568725 \h  87  

  HYPERLINK \l "_Toc164568726"  8.2 Budget Level for On-Road Mobile
Source Emissions	  PAGEREF _Toc164568726 \h  87  

  HYPERLINK \l "_Toc164568727"  Reasonable Further Progress Mobile
Budgets	  PAGEREF _Toc164568727 \h  88  

  HYPERLINK \l "_Toc164568728"  Attainment Year Mobile Budgets	  PAGEREF
_Toc164568728 \h  88  

  HYPERLINK \l "_Toc164568729"  8.3 Trends in Mobile Emissions	  PAGEREF
_Toc164568729 \h  89  

  HYPERLINK \l "_Toc164568730"  9.0  Moderate Area Plan Commitments	 
PAGEREF _Toc164568730 \h  90  

  HYPERLINK \l "_Toc164568731"  9.1 Schedules of Adopted Control
Measures	  PAGEREF _Toc164568731 \h  90  

  HYPERLINK \l "_Toc164568732"  9.2 Stationary Source Thresholds	 
PAGEREF _Toc164568732 \h  93  

  HYPERLINK \l "_Toc164568733"  10.0  Contingency Measures	  PAGEREF
_Toc164568733 \h  94  

  HYPERLINK \l "_Toc164568734"  10.1  Contingency Overview	  PAGEREF
_Toc164568734 \h  94  

  HYPERLINK \l "_Toc164568735"  10.2  Contingency Emission Reductions
for RFP Demonstration	  PAGEREF _Toc164568735 \h  94  

  HYPERLINK \l "_Toc164568736"  Surplus Reductions from Existing
Measures	  PAGEREF _Toc164568736 \h  95  

  HYPERLINK \l "_Toc164568737"  10.3  Contingency Emission Reductions
for Failure to Attain	  PAGEREF _Toc164568737 \h  96  

  HYPERLINK \l "_Toc164568738"  11.0 Weight of Evidence Attainment
Demonstration	  PAGEREF _Toc164568738 \h  98  

  HYPERLINK \l "_Toc164568739"  11.1  Ambient Air Monitoring
Measurements and Trends	  PAGEREF _Toc164568739 \h  99  

  HYPERLINK \l "_Toc164568740"  The Ambient Monitoring Network	  PAGEREF
_Toc164568740 \h  99  

  HYPERLINK \l "_Toc164568741"  Ozone Trends	  PAGEREF _Toc164568741 \h 
100  

  HYPERLINK \l "_Toc164568742"  Temperature Adjusted Ozone Trend	 
PAGEREF _Toc164568742 \h  107  

  HYPERLINK \l "_Toc164568743"  Ambient Ozone Precursor Trend	  PAGEREF
_Toc164568743 \h  108  

  HYPERLINK \l "_Toc164568744"  Supplemental Monitoring Initiatives	 
PAGEREF _Toc164568744 \h  109  

  HYPERLINK \l "_Toc164568745"  11.2  The Challenge of Interstate
Transport	  PAGEREF _Toc164568745 \h  111  

  HYPERLINK \l "_Toc164568746"  Westerly Transport	  PAGEREF
_Toc164568746 \h  113  

  HYPERLINK \l "_Toc164568747"  Nocturnal Low Level Jet Transport	 
PAGEREF _Toc164568747 \h  119  

  HYPERLINK \l "_Toc164568748"  Apportionment of Ozone Transport	 
PAGEREF _Toc164568748 \h  123  

  HYPERLINK \l "_Toc164568749"  11.3  Modeled and Probable Range
Attainment Demonstration	  PAGEREF _Toc164568749 \h  125  

  HYPERLINK \l "_Toc164568750"  Evaluation of Model Abilities	  PAGEREF
_Toc164568750 \h  125  

  HYPERLINK \l "_Toc164568751"  Base Case and Future Year Modeling	 
PAGEREF _Toc164568751 \h  134  

  HYPERLINK \l "_Toc164568752"  Probable Ranges	  PAGEREF _Toc164568752
\h  134  

  HYPERLINK \l "_Toc164568753"  Alternative Control Strategies	  PAGEREF
_Toc164568753 \h  139  

  HYPERLINK \l "_Toc164568754"  12.0 Attainment Demonstration	  PAGEREF
_Toc164568754 \h  143  

  HYPERLINK \l "_Toc164568755"  12.1  Modeling Study Overview	  PAGEREF
_Toc164568755 \h  143  

  HYPERLINK \l "_Toc164568756"  Background and Objectives	  PAGEREF
_Toc164568756 \h  143  

  HYPERLINK \l "_Toc164568757"  Relationship to Regional Modeling
Protocols	  PAGEREF _Toc164568757 \h  146  

  HYPERLINK \l "_Toc164568758"  Conceptual Description	  PAGEREF
_Toc164568758 \h  146  

  HYPERLINK \l "_Toc164568759"  12.2	Domain and Data Base Issues	 
PAGEREF _Toc164568759 \h  147  

  HYPERLINK \l "_Toc164568760"  Episode Selection	  PAGEREF
_Toc164568760 \h  147  

  HYPERLINK \l "_Toc164568761"  Size of the Modeling Domain	  PAGEREF
_Toc164568761 \h  147  

  HYPERLINK \l "_Toc164568762"  Horizontal Grid Size	  PAGEREF
_Toc164568762 \h  147  

  HYPERLINK \l "_Toc164568763"  Vertical Resolution	  PAGEREF
_Toc164568763 \h  148  

  HYPERLINK \l "_Toc164568764"  Initial and Boundary Conditions	 
PAGEREF _Toc164568764 \h  148  

  HYPERLINK \l "_Toc164568765"  Meteorological Model Selection and
Configuration	  PAGEREF _Toc164568765 \h  149  

  HYPERLINK \l "_Toc164568766"  Emissions Model Selection and
Configuration	  PAGEREF _Toc164568766 \h  149  

  HYPERLINK \l "_Toc164568767"  Air Quality Model Selection and
Configuration	  PAGEREF _Toc164568767 \h  150  

  HYPERLINK \l "_Toc164568768"  Quality Assurance	  PAGEREF
_Toc164568768 \h  150  

  HYPERLINK \l "_Toc164568769"  12.3	Model Performance Evaluation	 
PAGEREF _Toc164568769 \h  151  

  HYPERLINK \l "_Toc164568770"  Overview	  PAGEREF _Toc164568770 \h  151
 

  HYPERLINK \l "_Toc164568771"  Diagnostic and Operational Evaluation	 
PAGEREF _Toc164568771 \h  151  

  HYPERLINK \l "_Toc164568772"  Summary of Model Performance	  PAGEREF
_Toc164568772 \h  155  

  HYPERLINK \l "_Toc164568773"  12.4	Attainment Demonstration	  PAGEREF
_Toc164568773 \h  157  

  HYPERLINK \l "_Toc164568774"  Overview	  PAGEREF _Toc164568774 \h  157
 

  HYPERLINK \l "_Toc164568775"  Modeling Attainment Test	  PAGEREF
_Toc164568775 \h  157  

  HYPERLINK \l "_Toc164568776"  Unmonitored Area Analysis	  PAGEREF
_Toc164568776 \h  161  

  HYPERLINK \l "_Toc164568777"  Emissions Inventories	  PAGEREF
_Toc164568777 \h  162  

  HYPERLINK \l "_Toc164568778"  Summary and Conclusions of Attainment
Demonstration	  PAGEREF _Toc164568778 \h  162  

  HYPERLINK \l "_Toc164568779"  12.5	Procedural Requirements	  PAGEREF
_Toc164568779 \h  168  

  HYPERLINK \l "_Toc164568780"  Reporting	  PAGEREF _Toc164568780 \h 
168  

  HYPERLINK \l "_Toc164568781"  Data Archival and Transfer of Modeling
Files	  PAGEREF _Toc164568781 \h  168  

 

Appendix A – (Chapter 3) Base Year Emission Inventory

Appendix A-1: Base Year Emission Inventory Methodologies

Appendix A-2: Point Source Base Year Inventory

Appendix A-3: Quasi-Point Source Base Year Inventory

Appendix A-4: Area Source Base Year Inventory

Appendix A-5: Mobile Source Base Year Inventory

Appendix A-6: Nonroad Source Base Year Inventory

Appendix B – (Chapter 4) Projection Year Methodologies

Appendix C – (Chapter 5) RFP Calculations

Appendix D – (Chapter 6) Regulatory Support Information

Appendix E – (Chapter 7) RACM Measures List

Appendix F – (Chapter 8) Mobile Budget Documentation

Appendix G – (Chapter 11) WOE Documentation

Appendix H – (Chapter12) Attainment Demonstration Modeling
Documentation

Appendix G – (Chapter 11) WOE Documentation

Appendix G-1:	Ozone Sensitivity to NOx Emissions

Appendix G-2:	Animated Google Earth Movie of Westerly Transport [DVD]

Appendix G-3:	Animated Google Earth Movie of Nocturnal Low Level Jet
Transport [DVD]

Appendix G-4:	Radar Wind Profiler Observations in Maryland:  A
Preliminary Climatology of the Low Level Jet

Appendix G-5:	The Low Level Jet in Maryland:  Profiler Observations and
Preliminary Climatology

Appendix G-6:	Characterizing Maryland Ozone by Meteorological Regime

Appendix G-7:	Regional Nature of Ozone Transport

Appendix G-8:	Comparison of CMAQ-calculated ozone to surface and aloft
measurements

Appendix G-9:	Uncertainty in CMAQ and Over-predictions of Future Year
Ozone Design Values

Appendix G-10:	Analysis of the Details of CMAQ 4.5.1 Chemistry

Appendix G-11:	The Role of Land-Sea Interactions on Ozone Concentrations
at the Edgewood, Maryland Monitoring Site

Appendix G-12:	A Summary of the 2002 Base Case and 2009 Future Base Case
CMAQ Runs

Appendix G-13:	The Relationship between Urban Tree Cover and Ground
Level Ozone 

Appendix G-14:	Air Quality Benefits of an Aggressive Telecommute
Strategy

Appendix G-15:	WOE Probable Range With Voluntary Measures

1.0  Executive Summary

Introduction

Ground level ozone is considered a significant health based pollutant
and the US Environmental Protection Agency (EPA) has set a specific
national ambient air quality standard for ozone to best protect public
health.  This standard, known as the 8-Hour Ozone standard, is
implemented under the federal Clean Air Act (CAA).  Areas of the county
that monitor air pollution above the federal standard are designated
“nonattainment” and are therefore required to develop and implement
air quality plans called State Implementation Plans or SIPs that show
how a particular region will reduce pollution to the point where the
region meets the federal standards. 

The Philadelphia Nonattainment Area (Philadelphia - Wilmington -
Atlantic City, PA - DE - MD - NJ ozone nonattainment region), which
includes Cecil County, Maryland, has been designated nonattainment under
the 8-Hour Ozone standard.  The following document explains the process
by which Cecil County and the region will reduce pollution and meet the
federal ozone standard by June 15th 2010, which is the designated
attainment date for the region.

This is a substantial good news story regarding Maryland’s improving
air quality.  The Maryland Department of the Environment (MDE) is very
proud of this SIP document as it shows, based on significant modeling
and weight of evidence analysis, that Cecil County will indeed attain
the ozone standard during the 2009 ozone season.   

Emissions

A significant portion of this document is related to emissions. 
Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOC) emissions
create ozone under heat and sunlight.  Reductions in these precursor
emissions are a necessity to reduce ozone pollution.  MDE is responsible
for creating an emissions inventory for NOx and VOC that estimates the
actual emissions created by all the different emission sources in our
state.  Emissions come from a variety of sources including mobile
sources like cars and trucks, point sources like power plants, area
sources like lawnmowers, and non-road sources like construction
equipment and all terrain vehicles.  

This document details the current emission inventory for NOx and VOC and
predicted emissions for the future.  It is important to predict
emissions in the future to track progress from emission reduction
programs and for incorporation into attainment analyses that predict
whether a region will meet the air quality standard or not. 

The good news exhibited by this document is that NOx and VOC emissions
are going down in Cecil County and the region.  Control programs aimed
at reducing emissions have been developed and implemented and the
reductions required by these programs are significant.  Population
growth, economic growth, and the public need tend to tax the emission
reductions that come from control programs.  Despite these obstacles,
the overall trend in ozone forming emissions is downward and MDE
predicts that with additional reductions will come even cleaner air.

Control Programs

Over the past several decades MDE has adopted and implemented numerous
control programs (laws, regulations, voluntary measures) that reduce NOx
and VOC emissions in Maryland.  In addition, several new control
measures are being adopted specifically to help Maryland attain the
federal ozone standard.  The programs, in addition to the existing
control programs that continue to be implemented and enforced, allow
Maryland to develop an attainment demonstration that shows how Maryland
will meet the federal ozone standard.

The most significant new control program is the Maryland Healthy Air Act
(HAA), which significantly reduces NOx from Maryland’s older coal
burning power plants.  The HAA is more stringent than the parallel
federal rule called the Clean Air Interstate Rule and is the most
substantial emission control program ever adopted in Maryland.  The HAA
is the most aggressive power plant control program on the east coast. 
Overall, the HAA will reduce Maryland power plant NOx emissions by 70%
(compared to 2002 levels) in 2009 and by 75% by 2012.  The 2009
reductions are a significant part of the attainment scheme developed by
MDE to meet the federal ozone standard. 

Additional control programs being implemented to help Maryland meet the
federal ozone standard include several VOC rules targeted at adhesives
and sealants, lower VOC portable fuel containers, and lower VOC consumer
products.  Other non-traditional measures include an aggressive telework
program and a tree canopy program. 

The following is a brief summary of new control measures being
implemented to assist Cecil County with attaining the 8-hour Ozone
standard.  

Control Measures Summary*





2009

Control Measure

VOC

(tpd)	NOx

(tpd)

On Road Mobile Measures

1.85	3.78

Stage II/Refuel

0.00	0.00

OTC - Consumer Products Phase 1

0.14	0.00

OTC - Consumer Products Phase 2

0.02	0.00

OTC –  Low VOC Paints - AIM

0.39	0.00

OTC - PFC Phase 1

0.32	0.00

OTC - PFC Phase 2

0.03	0.00

OTC - Industrial Adhesives

0.10	0.00

Open Burning

0.00	0.00

Nonroad Model

1.50	0.36

Railroads (Tier 2)

0.00	0.16

Healthy Air Act (HAA)

0.00	0.00

Total 

4.35	4.30

* All control level totals are rounded

Modeling

A significant part of the attainment demonstration for Maryland consists
of air quality modeling analysis.  Required by the CAA, air quality
models are run to examine what future air quality conditions will be and
whether a region will attain the standard or not by their designated
attainment date.  The models are not relied upon as the only attainment
test, but are an important part of the attainment demonstration for
Maryland. 

The air quality modeling analysis completed for this SIP shows that
Cecil County, Maryland will attain the 8-hour ozone standard during the
2009 ozone season.  The predicted ozone level for the Fair Hill Monitor
in Cecil County for the summer of 2009 is 81 ppb, lower than the
standard of 85 ppb.  Other locations in the larger Philadelphia
Nonattainment area are not showing such robust improvements in overall
air quality and the direct modeling completed for this SIP does not show
predicted air quality levels below 85 ppb.  However, using other
analytical methods under an approach called weight of evidence, Maryland
believes that the entire region will indeed attain the 8-hour ozone
standard.

	

Weight of Evidence

As mentioned above, air quality models are not the only tool available
that can be used to predict attainment of the federal ozone standard.  A
weight of evidence approach can be used to further analyze air quality
data, trends, meteorology, model performance and model chemistry.  The
MDE has developed a significant weight of evidence that Cecil County and
the Philadelphia Nonattainment area will indeed meet the federal ozone
standard during the 2009 ozone season.  

Some of the weight of evidence analyses utilized for the region
includes:

an analysis of the chemistry component of the Community Multi-scale Air
Quality (CMAQ) model

an analysis to the ozone sensitivity to NOx emission reductions

the effect of land-sea interactions on ozone at the Edgewood air quality
monitor

an analysis of the regional nature of ozone transport

an analysis of the potential benefits of an aggressive telecommuting
strategy

an analysis of the uncertainty in the CMAQ air quality model and the
over-prediction of ozone design values

an analysis of the effects of urban tree canopy cover on temperature and
ozone levels

In addition, other states in the nonattainment area are providing other
substantial weight of evidence analysis that lead to an attainment
demonstration for the region.  These additional weight of evidence
chapters from other states were not available in time for inclusion in
this SIP document.

Based on all of the above analysis and the air quality modeling
performed for Cecil County and the Philadelphia Nonattainment area,
there is a dramatic weight of evidence available that shows the region
will attain the 8-hour ozone standard.  The chart below shows a summary
of the Maryland ozone monitor design value ranges expected in the region
based on the modeling/ weight of evidence analysis.  All of the air
quality monitors in the region are predicted to be well below the 85ppb
8-hour ozone standard.







2.0  Introduction and Background

This document, entitled Cecil County, Maryland / Philadelphia
Nonattainment Area 8-Hour Ground Level Ozone State Implementation Plan,
presents the Maryland Department of the Environment's (MDE's) progress
in adopting and implementing air pollution control programs needed to
attain the 8-hour ozone standard by 2010 in Cecil County, Maryland. 

2.1  State Implementation Plans

The State Implementation Plan (SIP) is a detailed document required for
states or regions that do not meet air quality levels set by the federal
government.  The Plan identifies how that State will attain and/or
maintain the primary and secondary National Ambient Air Quality
Standards (NAAQS) set forth in section 109 of the Clean Air Act ("the
Act") and 40 Code of Federal Regulations 50.4 through 50.12 and which
includes federally-enforceable requirements.  Each State is required to
have a SIP that contains control measures and strategies that
demonstrate how each area will attain and maintain the NAAQS.  These
plans are developed through a public process, formally adopted by the
State, and submitted by the Governor's designee to EPA. The Clean Air
Act requires EPA to review each plan and any plan revisions and to
approve the plan or plan revisions if consistent with the Clean Air Act.

SIP requirements applicable to all areas are provided in section 110 of
the Act.  Part D of Title I of the Act specifies additional requirements
applicable to nonattainment areas. Section 110 and part D describe the
elements of a SIP and include, among other things, emission inventories,
a monitoring network, an air quality analysis, modeling, attainment
demonstrations, enforcement mechanisms, and regulations which have been
adopted by the State to attain or maintain NAAQS. EPA has adopted
regulatory requirements which spell out the procedures for preparing,
adopting and submitting SIPs and SIP revisions that are codified in 40
CFR part 51.  EPA's action on each State's SIP is promulgated in 40 CFR
part 52.

The contents of a typical SIP fall into several categories: (1)
State-adopted control measures which consists of either
rules/regulations or source-specific requirements (e.g., orders and
consent decrees); (2) State-submitted comprehensive air quality plans,
such as attainment plans, maintenance plans rate of progress plans, and
transportation control plans demonstrating how these state regulatory
and source-specific controls, in conjunction with federal programs, will
bring and/or keep air quality in compliance with federal air quality
standards; (3) State- submitted "non-regulatory" requirements, such as
emission inventories, small business compliance assistance programs;
statutes demonstrating legal authority, monitoring networks, etc.); and
(4) additional requirements promulgated by EPA (in the absence of a
commensurate State provision) to satisfy a mandatory section 110 or part
D (Clean Air Act) requirement.

Once the Administrator of the EPA approves a state plan, the plan is
enforceable as a state law and as federal law under Section 113 of the
Act. If the SIP is found to be inadequate in EPA's judgment to attain
the NAAQS in all or any region of the state, and if the state fails to
make the requisite amendments, under Section110(c)(1), the EPA
Administrator may issue amendments to the SIP that are binding.  EPA is
required to impose severe sanctions on the states under three
circumstances: the state's failure to submit a SIP revision; on the
finding of the inadequacy of the SIP to meet prescribed air quality
requirements; and the state's failure to enforce the control strategies
that are contained in the SIP.  Sanctions include: withholding federal
funds for highway projects other than those for safety, mass transit, or
transportation improvement projects related to air quality improvement
or maintenance beginning 24 months after EPA announcement. No federal
agency or department will be able to award a grant or fund, license, or
permit any transportation activity that does not conform to the most
recently approved SIP.

2.2  Clean Air Act

The Clean Air Act was passed in 1970 to protect public health and
welfare. Congress amended the Act in 1990 to establish requirements for
areas not meeting the National Ambient Air Quality Standards. The Clean
Air Act Amendments of 1990 (CAAA) established a process for evaluating
air quality in each region and identifying and classifying nonattainment
areas according to the severity of its air pollution problem.  The CAAA
defines ground-level ozone as a criteria pollutant. In 1979 EPA
promulgated the 0.12 parts per million (ppm) 1-hour ozone standard.  In
1997, EPA issued a revised and stricter ozone standard of 0.08 ppm, or
85 parts per billion (ppb), measured over an eight-hour period. The
one-hour ozone standard was consequently revoked in June 2005. The Clean
Air Act also sets National Ambient Air Quality Standards for five other
criteria pollutants; carbon monoxide, particulate matter, lead, sulfur
dioxide and nitrogen dioxide. 

 

In April 2004, EPA designated the Philadelphia - Wilmington - Atlantic
City, PA - DE - MD - NJ ozone nonattainment region as a “moderate”
nonattainment area for the eight-hour ozone standard under Subpart 2
area of Section 182 part b.  Cecil County is the Maryland portion of the
Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ ozone
nonattainment region.  A map of the nonattainment area is shown in
Figure 2.1.   

Figure 2.1 - Map of the Philadelphia - Wilmington - Atlantic City, PA -
DE - MD - NJ ozone nonattainment region

To meet the federal 8-hour standard for ozone, nonattainment areas are
required to develop their SIP documents to reduce ozone-forming
emissions of volatile organic compounds (VOCs) by at least 15 percent
between 2002-2008, and to reduce all ozone precursor emissions to a
level sufficient to attain the federal eight-hour standard by June 15,
2010. However, the region is required to demonstrate attainment of the
standard by the end of the last ozone season before that date, which is
September 2009. 

2.3  SIP Requirements for Moderate Nonattainment Areas

The Clean Air Act Section 182 sets requirements for nonattainment areas
based on their classification.  Under the 1hr Ozone Standard, Cecil
County was classified as severe.  Under the 8-hour Ozone Standard Cecil
County was reevaluated and classified as moderate.  

Based on the Severe 1hr Ozone Standard classification very stringent
measures were required in Cecil County:

Low new source review threshold for point sources at 25 tons per year; 

Low threshold for definition of “Major” source requiring controls to
25 tons per year; 

New Source Review offsets at 1.3 to 1

Enhanced I&M

Maryland will continue to implement the above listed 1hr ozone
requirements.  In addition to these restrictive severe area
requirements, Maryland will also implement the necessary moderate area
requirements listed below.

 

Reasonable Further Progress: 15% emission reduction from baseline 

Attainment demonstration: Due 3 years from designation 

NSR permits: required for new or modified major stationary sources 

NOx control for RACT: requirement for major stationary VOC sources also
applies to major NOx sources 

RACM/RACT: RACT required for all Control Technique Guideline (CTG)
sources and all other major sources  

Stage II vapor recovery: required for all gas stations  

Contingency measures: required for failure to meet Reasonable Further
Progress (RFP) milestones or attain 

2.4  Eight-Hour Ozone Standard

In 1997, EPA issued a revised ozone health standard based on an 8-hour
measurement to protect human health against longer exposure periods.
Since the late 1980’s, more than 3,000 published health studies
indicated that health effects occur at levels lower than the previous
standard and that exposure times longer than one hour are of concern.
EPA established an 8-hour standard at 0.08 ppm / 85 ppb and defined the
new standard as a “concentration-based” form, specifically the
3-year average of the 4th highest daily maximum 8-hour ozone
concentration.  

 

EPA changed the form of the standard to a concentration-based form
because it more accurately reflects actual human exposure and related
health effects. Even at relatively low levels, ozone may cause
inflammation and irritation of the respiratory tract, particularly
during physical activity. The resulting symptoms can include breathing
difficulty, coughing, and throat irritation. Breathing ozone can affect
lung function and worsen asthma attacks. Ozone can increase the
susceptibility of the lungs to infections, allergens, and other air
pollutants. Medical studies have shown that ozone damages lung tissue
and complete recovery may take several days after exposure has ended.

2.5  Ground Level Ozone

Ground-level ozone is an extremely reactive gas comprised of three atoms
of oxygen. Ozone (the primary constituent of smog) continues to be a
pollution problem throughout many areas of the United States. Unlike
many other pollutants, ground-level ozone is not directly emitted into
the atmosphere from a specific source. Instead, ground-level ozone is
formed when nitrogen oxides (NOx) chemically react with volatile organic
compounds (VOCs) through a series of complicated chemical reactions in
the presence of strong sunshine (ultraviolet light). 

Because ozone formation is greatest when the sunlight is most intense,
the peak ozone levels typically occur in Maryland during hot, dry,
stagnant summertime conditions generally referred to as the ozone season
(May 1 to September 30). Peak Ozone concentrations exhibit a clear
seasonal cycle, with concentrations rising with the onset of warmer
weather in the spring and declining again as the autumn approaches.
Changing weather patterns can significantly contribute to yearly
differences in ozone concentrations. Years with summertime weather
conditions that are hot and dry will generally result in many more days
of poor air quality than cool and wet summers.

Figure 2.2 Formation of Ground Level Ozone

The formation of ozone is not an instantaneous process, nor is it
limited in geographical scope.  While many urban areas tend to have high
levels of ozone, even rural areas are subject to increased ozone levels
because wind carries ozone, and pollutants that form it, hundreds of
miles from their original sources. Numerous studies and modeling data
show compelling evidence that weather patterns often transport ozone,
and the pollutants responsible for ozone formation, well beyond the
locality that produced the emissions. In many cases, unhealthy days of
air pollution experienced in Maryland are exacerbated by pollutants
transported into Maryland from neighboring states.

2.6  Air Pollution and the Chesapeake Bay

Typically, air pollution is thought of as smog that affects people’s
health and reduces visibility. However, air pollution also contributes
to land and water pollution that affects the health of the Chesapeake
Bay’s resources - its fish, shellfish, and other animals. Over the
last thirty years, research has provided us with more knowledge on how
air pollution can directly affect the Bay.

Pollutants released into the air will eventually make their way back
down to the earth’s surface. Some of the factors that determine how
far pollutants can travel through the air include, the makeup of the
pollutant, weather conditions (wind, temperature, humidity), type and
height of the emission source (smokestack, automobile tail pipe), and
the presence of other chemicals in the air. Airborne pollutants fall to
the earth’s surface by wet deposition (precipitation), or dry
deposition (settling or adsorption). Airborne pollutants that deposit on
the landscape can be transported into streams, rivers, and the Bay by
runoff or through groundwater flow.

Excess nitrogen and chemical contaminants from atmospheric deposition
impact the Chesapeake Bay and its watershed. Too much nitrogen entering
the Chesapeake Bay leads to eutrophication; a process that causes an
accelerated growth of algae. Too much algae in the Bay blocks sunlight
needed for submerged aquatic vegetation to grow. Also, when the algae
dies it sinks to the bottom and decomposes in a process that depletes

the oxygen in the water.

The effects of nitrogen can also be seen in acid rain. Nitrogen oxides
(NOx) are one of the key air pollutants that cause acid deposition, and
results in adverse effects on aquatic and terrestrial ecosystems. Acid
deposition increases the acidity of water and soils. Increases in water
acidity can impair the ability of certain fish and aquatic life to grow,
reproduce, and survive. Increases in soil acidity can impair the ability
of some types of trees to grow and resist disease.

2.7  Health Effects

Ozone is a highly reactive gas that reacts strongly with living tissues,
as well as many man-made substances. Ninety percent of the ozone
breathed into the lungs is never exhaled, ozone molecules react with
lung tissue to cause several health consequences. Too much ozone in the
air we breathe can be harmful to people who work or exercise outdoors
regularly, anyone with respiratory difficulties, and especially to our
children. The most common symptom that people have when exposed to ozone
is pain when taking a deep breath.  Exposure to ozone can result in both
long-term and short-term effects in healthy individuals as well as those
who are already sensitive to air pollution, such as children, asthmatics
and the elderly.

Ozone long-term effects may include reduced lung function, scarring of
lung tissue, and even premature death.    Research suggests that
repeated exposure to ozone may cause damage to lung tissue, thereby
reducing lung function.  According to EPA, “Long-term exposures to
ozone can cause repeated inflammation of the lung, impairment of lung
defense mechanisms, and irreversible changes in lung structure, which
could lead to premature aging of the lungs and/or chronic respiratory
illnesses such as emphysema and chronic bronchitis.” 

Children are at greater risk for ozone-related respiratory problems
because their lungs are still developing, they breathe more rapidly, and
they play outside during the afternoons when ozone is at its highest
levels. Children also inhale more air, hence more pollution per pound of
body weight than adults do.   Additionally, anyone suffering from lung
disease has even more trouble breathing when air is polluted with high
levels of ozone. Prolonged exposure, even to relatively low levels of
ozone, can even significantly reduce a healthy adult’s lung function. 

Short-term effects among healthy populations include impaired lung
function and reduced ability to perform physical exercise.  For example,
healthy young people developed significant reduction of lung function,
additional coughing and breathing pains, and enhanced airway reactivity
to irritants when exposed to ozone at concentrations between 80-120
parts per billion (ppb) for 6.6 to 7.0 hours while moderately
exercising.  For reference, the new ozone standard issued by EPA in 1997
is a concentration of 0.08 ppm averaged over an eight-hour time period. 
The Philadelphia Nonattainment Area does not currently achieve this
standard.  Among people who are especially sensitive to ozone pollution,
short-term effects include increased hospital admissions and emergency
room visits for respiratory diseases, like asthma.  

In sum, health effects from exposure to ozone can include any or all of
the following:

(	Increased susceptibility to respiratory infection.

(	Impaired lung function and reduced ability to perform physical
exercise.

(	Severe lung swelling and death, due to short-term exposures greater
than 

300 ppb.

Increased hospital admissions and emergency room visits from respiratory

            diseases. 

Ozone also poses a threat to the health of natural ecosystems. 
Scientific evidence suggests that air pollution weakens the immune
systems of many types of vegetation and can cause significant crop
damage.  In addition, rain and snow wash air pollution deposited on
vegetation and architectural surfaces into the streams and rivers of the
region and finally into the Chesapeake Bay. 

2.8  Maryland Specific Health Effects

According to the U.S. Census Bureau, Census 2000 data, there are
5,296,486 people living in Maryland, of whom 1,136,846 were under 15
years of age, and of whom 599,307 were 65 or over.  This means that the
total number of children and elderly in Maryland was 1,736,153. 
Approximately one third of Maryland’s population is more likely to
suffer the adverse effects of air pollution simply as a result of their
age.    

According to an April 2006 report from the American Lung Association,
the group of people with respiratory disease in the state of Maryland
includes: 

274,967 adult asthmatics and 100,370 child asthmatics;

147,226 residents with chronic bronchitis; and

57,310 residents with emphysema.

2.9  The Impact of Ozone on Agriculture

Because ozone formation requires sunlight, periods of high ozone
concentration coincide with the agriculture growing season in Maryland.
Ozone damage to plants can occur with or without any visible signs.
Consequently, many farmers are unaware that ozone is reducing their
yields. Ozone enters the plant’s leaves through its gas exchange pores
(stomata), just as other atmospheric gases do in normal gas exchange.
The ozone then dissolves in the water within the plant and reacts with
other chemicals, causing a variety of problems.

Ozone damage in the plant causes photosynthesis to slow, resulting in
slower plant growth. Such ozone induced problems also decrease the
numbers of flowers and fruits a plant will produce, and impair water use
efficiency and other functions. Plants weakened by ozone may be more
susceptible to pests, disease, and drought. 

Most studies of the economic impact of air pollution on agriculture have
found that a 25 percent reduction in ambient ozone would provide
benefits of at least $1-2 billion annually in the United States. 
Studies of soybean yields at the University of Maryland found a 10
percent loss of the soybean crop due to current levels of ozone in the
state. The same study showed that ozone exposure causes the loss of 6-8
percent of winter wheat and 5 percent of the corn crop yields to
Maryland farmers. 

2.10  The Air Quality Index (AQI)

The AQI is an index used for reporting forecasted and daily air quality.
The AQI uses both a color-coded and numerical scale to report how clean
or polluted the air is and what associated health effects might be of
concern. The AQI focuses on health effects people may experience within
a few hours or days after breathing polluted air. The AQI is calculated
for five major pollutants regulated by the Clean Air Act: particulate
matter, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide.

Figure 2.3 The Air Quality Index and Action Guide

Using the Air Quality Index, the Maryland Department of the Environment
and the Metropolitan Washington Council of Governments (COG) issue daily
air quality forecasts for the Baltimore metropolitan area (including
Cecil County), Washington metropolitan area, Western Maryland, and the
Eastern Shore. Extended range forecasts provide a three-day forecast so
people can better plan their week and take the opportunity to arrange
car pools, take mass transit, or take other actions to limit pollution
when air quality is predicted to be unhealthful.

MDE and COG issue the air quality forecasts to local media and hundreds
of businesses and individuals throughout the region. Anyone can sign up
to receive the free, daily email by visiting the AirWatch web site at
www.air-watch.net. The AirWatch web site provides the public with easy
access local and national air quality information. AirWatch offers daily
AQI forecasts and real-time AQI conditions throughout most of Maryland,
the District of Columbia, and Northern Virginia. Users of AirWatch may
also sign-up for AirAlerts to receive real-time email notifications for
when air quality reaches unhealthy levels in the region.

Figure 2.4 Air-Watch.net Real-time air quality data and Forecasts 

2.11  Sources of Ozone Pollution in the Cecil County Area

There are a number of diverse sources that discharge VOCs and NOx, the
two primary pollutants responsible for ozone formation.  Human made
sources, called anthropogenic sources, are divided into four categories:
 point, area, on-road mobile and non-road mobile sources.  A fifth
category, "biogenic" emissions, includes all naturally occurring sources
of VOC emissions from trees, crops and other forms of vegetation.

Point sources are primarily manufacturing businesses that produce
emissions equal to or greater than 10 tons per year (tpy) of VOCs or 25
tpy of NOx.  Large industrial plants such as power plants and chemical
manufacturers are examples of point sources.

Area sources are smaller sources of air pollution whose emissions are
too small to be measured individually.  Examples of area sources include
commercial and consumer products (such as paints and hairspray),
bakeries, gasoline refueling stations, printing facilities, and autobody
refinishing shops.

Sources of air pollution that are not stationary are referred to as
mobile sources and are broken down into two categories:  on-road mobile
sources and non-road mobile sources.  The former include cars, vans,
trucks and buses (i.e. vehicles that operate on highways).  Non-road
mobile sources include boats, lawn and garden equipment, construction
equipment and locomotives.

Table 2-1 

TOP TEN SOURCES OF MAN-MADE VOLATILE ORGANIC COMPOUNDS (VOCs) IN THE
CECIL COUNTY AREA FOR 2002 and 2009 

  

	VOC

(Tons/Day)

Rank	Source Category	Source	2002	2009

1	Nonroad	Pleasure Craft Total	5.55	3.98

2	On-Road Mobile	Cars, Buses, Trucks	4.00	2.16

3	Nonroad	Recreational Equipment Total	1.68	2.45

4	Area	Architectural Surface Coatings	1.12	0.88

5	Area	Commercial & Consumer Solvents	0.87	0.83

4	Nonroad	Lawn and Garden Total	0.72	0.51

5	Area	Portable Fuel Containers	0.70	0.41

7	Area	Industrial Surface Coating	0.54	0.68

8	Area	Pesticide Application	0.37	0.37

9	Area	Residential Fuel Combustion	0.34	0.38

10	Area	Gasoline Marketing	0.31	0.35



	16.20	12.98



*The emissions estimates above are rounded to the nearest whole number. 
The figures are MDE’s best estimates.  Total anthropogenic VOC
emissions in the Cecil County area were 17.58 tons per day in 2002 and
14.36 tons per day in 2009.  

Table 2-2 

TOP TEN SOURCES OF MAN-MADE NITROGEN OXIDES (NOx) IN THE CECIL COUNTY
AREA IN 2002 and 2009

  



	NOx

(Tons/Day)

Rank	Source Category	Source	2002	2009

1	On-Road Mobile	Cars, Buses, Trucks	14.21	7.23

2	Nonroad	Construction and Mining	1.02	0.85

3	Nonroad	Railroad-Line Haul	0.59	0.43

4	Nonroad	Pleasure Craft	0.44	0.58

5	Nonroad	Agricultural	0.37	0.32

6	Nonroad	Industrial	0.27	0.17

7	Area	Residential Fuel Combustion	0.10	0.11

8	Nonroad	Lawn and Garden	0.09	0.08

9	Nonroad	Recreational	0.06	0.08

10	Nonroad	Marine Vessels	0.06	0.08



	17.22	9.93



*The emissions estimates above are rounded to the nearest whole number. 
The figures are MDE's best estimates.  Total anthropogenic NOx emissions
in the Cecil County area were 17.40 tons per day in 2002 and 10.29 tons
per day in 2009  

2.12  Frequency of Violation of Federal Health Standard for Ozone 

Since the Clean Air Act Amendments of 1990, Maryland has made
significant improvements in the quality of air. National, State, and
Local programs have all contributed to dramatically limit the amount of
pollution that is generated, which has reduced the number of days that
unhealthful air is experienced throughout the region. Mandated
reductions in emissions from businesses and industries, and
technological improvements in automobiles have brought about a steady
progress in air quality. 

The federal 8-hour ozone standard is set at 0.08 parts per million (85
parts per billion) of ozone averaged over an eight hour period. Figure
2.5 applies the eight-hour standard to historic data and shows the
number of days that exceeded levels under the new standard.  The figure
also clearly shows an improving trend for Maryland’s air quality since
1980. While annual fluctuations can be attributed to weather (hot,
stagnant summers are favorable for ozone formation), the downward trend
is indicative of controls on sources of air pollution and the resulting
levels of ozone precursors present in the ambient air. 

Figure 2.5 Maryland 8-Hour Ozone Exceedance Days per Year

2.13  Required SIP Principles

Section 110 of the 1990 CAAA specifies the conditions under which EPA
approves SIP submissions. These requirements are being followed by the
Maryland Department of the Environment in developing this air quality
plan or SIP. In order to develop effective control strategies, EPA has
identified four fundamental principles that SIP control strategies must
adhere to in order to achieve the desired emissions reductions. These
four fundamental principles are outlined in the General Preamble to
Title I of the Clean Air Act Amendments of 1990 at Federal Register
13567 (EPA, 1992a). The four fundamental principles are:

emissions reductions ascribed to the control measure must be
quantifiable and    measurable;

the control measures must be enforceable, in that the state must show
that they have adopted legal means for ensuring that sources are in
compliance with the control measure; 

measures are replicable; and 

the control strategy be accountable in that the SIP must contain
provisions to track emissions changes at sources and to provide for
corrective actions if the emissions reductions are not achieved
according to the plan.



2.14  Sanctions

EPA must impose various sanctions if the State does not submit a plan;
or

submits a plan that the EPA does not approve; or fails to implement the
plan. These sanctions include: withholding federal highway funding;
withholding air quality planning grants; and imposing a federal plan
(“federal implementation plan.”). Failure to submit or implement a
plan will have significant consequences for compliance with conformity
requirements.

2.15  Reasonable Further Progress

As a moderate area, EPA requires the Philadelphia - Wilmington -
Atlantic City, PA - DE - MD - NJ ozone nonattainment area (Philadelphia
NAA) to demonstrate Reasonable Further Progress towards attainment by
2008.  Each state in the Philadelphia NAA is responsible for meeting
this requirements for the counties from each state connected to the
nonattainment area.  

EPA’s implementation guidance requires that a state’s moderate ozone
nonattainment areas, such as Cecil County, MD, with an approved 15% VOC
reduction plan for the period 1990-1996 (required for former 1-hour
ozone non-attainment areas) demonstrate a 15% Reasonable Further
Progress by 2008.  Chapter 5 contains Cecil County’s reasonable
further progress demonstration for the years 2002-2008. The region will
need to fulfill the 2002-2008 reasonable further progress requirements
by January 1, 2009.  

 

In order to demonstrate reasonable further progress, a region must show
that its expected emissions, termed controlled inventories, of NOx and
VOC will be less than or equal to the target levels set for the end of
the reasonable further progress period, or “milestone year”. For the
RFP period 2002-2008, the “target inventories” of emissions are the
maximum quantity of anthropogenic emissions permissible during the 2008
milestone year. 

2.16  Analysis of Reasonably Available Control Measures (RACM)

An extensive list of potential control measures was analyzed and
evaluated against criteria used for potential RACM measures. Individual
measures must meet the following criteria: will reduce emissions in
Cecil County by the beginning of the 2008 ozone season (May 1, 2008);
are enforceable; are technically feasible; are economically feasible,
defined as a cost of $3,500 to $5,000 per ton or less; would not create
substantial or widespread adverse impacts within the region; and do the
emissions from the source being controlled exceed a de minimus
threshold, defined as 0.1 tons per day.  Based on the analysis completed
for Cecil County which relied heavily upon a very formal RACM analysis
completed for the Washington DC Nonattainment area (where MDE actively
participated in a RACM workgroup) there were no identified RACM measures
that if implemented would advance attainment in Cecil County.

2.17  Contingency Measures

In the event that the reductions anticipated in the 2008 Reasonable
Further Progress demonstrations or the 2009 attainment demonstration are
not realized within the timeframes specified, there must be contingency
measures ready for implementation. EPA issued guidance says that
contingency measures must provide for a 3% reduction in adjusted 2002
base year inventory for both Reasonable Further Progress and attainment.
A minimum of 0.3 % VOC must be included. The total reductions required
for RFP contingency are 0.51 tons per day of VOC, which Cecil County
meets  The measures proposed as contingency measures are listed in
Chapter 10.  Chapter 10 contains detail on these measures, how they
would be implemented, enforced, and the amount of reduction benefit
expected. 

3.0  The 2002 Base-Year Inventory 

 

3.1  Background and requirements 

 

The 2002 Base-Year Inventory is published in a separate document, "2002
Base Year Emissions Inventory & QA/QC Plan Maryland," (June 15, 2006). 
This document was submitted to EPA Region III.  This document was
prepared the Maryland Department of the Environment.  It is available
for inspection at the Air and Radiation Management Administration, 1800
Washington Boulevard, Suite 730, Baltimore, Maryland 21230.  Relevant
portions of this document including, source category listings and
descriptions, methods and data sources, emission factors, controls,
spatial and temporal allocations, and example calculations are included
in Appendix A1.  The full base year inventory document is attached to
this SIP in Appendix A.  

This emissions inventory covers Cecil County Maryland, which is
classified as a moderate nonattainment areas (part of the larger
Philadelphia NAA) for ozone by the U.S. Environmental Protection Agency
(EPA).  The 2002 emissions inventory is the starting point for
calculating the emissions reduction requirement needed to meet the 15%
VOC/NOx emissions (for man-made sources of emissions) reduction goal by
2008 to meet reasonable further progress requirements prescribed for
moderate nonattainment areas by the Clean Air Act Amendments and EPA. 

 

This separately published document, which was previously submitted to
EPA, addresses emissions of volatile organic compounds (VOCs), oxides of
nitrogen (NOx), and carbon monoxide (CO) on a typical summer ozone
season day and annual basis.  Included in the inventory are stationary
anthropogenic (man-made), biogenic (naturally occurring), and non-road
and on-road mobile sources of ozone precursors.   



Table 3-1

2002 Base-Year Inventory - Cecil County, MD

Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ
Nonattainment Area

 (Tons/Day)

Source Category	VOC 	NOx 10

Point	0.28	0.02

Area	4.93	0.20

Non-Road	8.37	2.97

On-Road Mobile	4.00	14.22

Biogenics	42.94	0

Total (excluding Biogenics)	17.58	17.40



3.2  Total Emissions by Source

 

 Point Sources 

 

For emissions inventory purposes, point sources are defined as
stationary, commercial, or industrial operations that emit more than 10
tons per year (tons/year) of VOCs or 25 tons/year or more of NOx or CO. 
The point source inventory consists of actual emissions for the
base-year 2002 and includes sources within the geographical area of the
Maryland portion of the Philadelphia - Wilmington - Atlantic City, PA -
DE - MD - NJ ozone nonattainment area. 

For source category listings and descriptions, methods and data sources,
emission factors, controls, spatial and temporal allocations, and
example calculations please refer to Appendix A1.  

For Base-Year Emission Inventory data please refer to Appendix A2.

Quasi-Point Sources 

 

The Maryland Department of the Environment Air and Radiation Management
has identified several facilities that due to size and/or function are
not considered point sources. The MDE has established quasi-point source
emissions to simplify the data collection process and the inventory
summary process.  These establishments contain a wide variety of air
emission sources, including traditional point sources, on-road mobile
sources, off-road mobile sources and area sources.  For each particular
establishment, the emissions from these sources are totaled under a
single point source and summary documents include these
“quasi-point” sources as point sources.  

Quasi-point sources will include all emissions at the facility
regardless of whether they are classified as point, area, nonroad, or
mobile source emissions.  These emissions are actual emissions reported
for the facilities.  No quasi-point sources were identified within the
Maryland portion of the Philadelphia - Wilmington - Atlantic City, PA -
DE - MD - NJ ozone nonattainment area.

For source category listings and descriptions, methods and data sources,
emission factors, controls, spatial and temporal allocations, and
example calculations please refer to Appendix A1.  

For Base-Year Emission Inventory data please refer to Appendix A3.

Area Sources 

 

Area sources are sources of emissions too small to be inventoried
individually and which collectively contribute significant emissions. 
Area sources include smaller stationary point sources not included in
the states' point source inventories such as printing establishments,
dry cleaners, and auto refinishing companies, as well as small
stationary sources. 

 

Area source emissions typically are estimated by multiplying an emission
factor by some known indicator of collective activity for each source
category at the county (or county-equivalent) level.  An activity level
is any parameter associated with the activity of a source, such as
production rate or fuel consumption that may be correlated with the air
pollutant emissions from that source.  For example, the total amount of
VOC emissions emitted by commercial aircraft can be calculated by
multiplying the number of landing and takeoff cycles (LTOs) by an
EPA-approved emission factor per LTO cycle for each specific aircraft
type.   

 

Several approaches are available for estimating area source activity
levels and emissions.  These include apportioning statewide activity
totals to the local inventory area and using emissions per employee (or
other unit) factors.  For example, solvent evaporation from consumer and
commercial products such as waxes, aerosol products, and window cleaners
cannot be routinely determined for many local sources.  The per capita
emission factor assumes that emissions in a given area can be reasonably
associated with population.  This assumption is valid over broad areas
for certain activities such as dry cleaning and small degreasing
operations.  For some other sources an employment based factor is more
appropriate as an activity surrogate.  

For source category listings and descriptions, methods and data sources,
emission factors, controls, spatial and temporal allocations, and
example calculations please refer to Appendix A1.  

For Base-Year Emission Inventory data please refer to Appendix A4.

Mobile Sources 

On-road mobile sources include all vehicles registered to use the public
roadways.  The predominant emission source in this category is the
automobiles, although trucks and buses are also significant sources of
emissions.

The computation of highway vehicle emissions required two primary
entities: a) vehicle emission factors and b) vehicle activity.

The Emission factors are generated by using the latest version of U.S.
EPA’s emission factor model MOBILE6.2. Vehicle activity (vehicle miles
traveled – termed VMT for short) was obtained from the Maryland State
Highway Administration (SHA) and the Maryland Department of
Transportation. VMT data from SHA, based on vehicle traffic counts on
the roadway system, is mainly used for rural counties. 

In a simple modeling scenario, the product of emission factor and
vehicle miles traveled should yield emission levels for that scenario.
Proper units and conversion are used to arrive at reasonable emission
estimates.

In a complex modeling scenario many types of emissions such as exhaust,
evaporative, diurnal, crankcase, refueling, etc., emissions are computed
separately and treated with the appropriate activity levels to yield a
complex model result.

MOBILE6 expects enormous amount of local data input such as the fleet
characteristics, fleet mileage accrual rates, speed, fuel parameters,
inspection and maintenance (I/M) program in place, weather data, and so
on.

In MOBILE6 emission factor model, the total highway vehicle population
is characterized by the following 16 composite vehicle type categories:

LDV	- Light-Duty Vehicles (Passenger Cars)

LDT1	- Light-Duty Trucks 1 

LDT2	- Light-Duty Trucks 2 

LDT3	- Light-Duty Trucks 3 

LDT4	- Light-Duty Trucks 4 

HDV2B- Class 2b Heavy Duty Vehicles

HDV3	- Class 3 Heavy Duty Vehicles 

HDV4	- Class 4 Heavy Duty Vehicles 

HDV5	- Class 5 Heavy Duty Vehicles 

HDV6	- Class 6 Heavy Duty Vehicles 

HDV7	- Class 7 Heavy Duty Vehicles 

HDV8A- Class 8a Heavy Duty Vehicles 

HDV8B- Class 8b Heavy Duty Vehicles 

HDBS	- School Buses

HDBT	- Transit and Urban Buses

MC	- Motorcycles

These composite vehicle types are further classified into 28 vehicle
types - gasoline or diesel vehicles depending on the vehicle types. All
motorcycles are gasoline based and transit and urban buses are diesels. 
The category of  “School Bus” can be either a gasoline or diesel
powered vehicle. 

MOBILE6 also allows for the modeling of other fuel type vehicle such as
hybrids and alternate fuel vehicles (AFV) as a special case in a complex
modeling initiative. 

MOBILE6 model produces emission factors, for each of the 28 vehicle
types, and one composite factor for all vehicle types.

A post-processing system takes care of all emission computations of the
modeling domain by aggregating the emissions from roads/links
appropriate to the area and produces meaningful reports by area, by
vehicle type and by roadway type. 

For source category listings and descriptions, methods and data sources,
emission factors, controls, spatial and temporal allocations, and
example calculations please refer to Appendix A1. 

For Base-Year Emission Inventory data please refer to Appendix A5.

Nonroad Sources 

 

Emissions for all nonroad vehicles and engines except airport (aircraft,
ground support equipment (GSE) and, auxiliary power units (APU)),
locomotives, and diesel marine vessels were calculated using EPA’s
NONROAD2005.0.0 (dt. 12/02/2005) model. Since the time it was first
issued on 12/02/2005, this model version underwent several corrections.
The base year nonroad inventory was created using the version current as
of 3/21/2006.  

 

Emissions from the “nonroad vehicles and engines” category result
from the use of fuel in a diverse collection of vehicles and equipment,
including vehicles and equipment in the following categories: 

 

Recreational vehicles, such as all-terrain vehicles and off-road
motorcycles; 

Logging equipment, such as chain saws; 

Agricultural equipment, such as tractors; 

Construction equipment, such as graders and back hoes; 

Industrial equipment, such as fork lifts and sweepers; 

Residential and commercial lawn and garden equipment, such as leaf and
snow blowers. 

Aircraft ground support equipment. 

 

The nonroad model estimates emissions for each specific type of nonroad
equipment by multiplying the following input data estimates: 

 

Equipment population for base year (or base year population grown to a
future year), distributed by age, power, fuel type, and application; 

Average load factor expressed as average fraction of available power; 

Available power in horsepower; 

Activity in hours of use per year; and 

Emission factor with deterioration and/or new standards. 

 

The emissions are then temporally and geographically allocated using
appropriate allocation factors. 

 

Aircraft (military, commercial, general aviation, and air taxi) and
auxiliary power units (APU) operated at airports along with locomotives
and diesel marine vessels are also considered nonroad sources and are
included in the nonroad category.  

 

For source category listings and descriptions, methods and data sources,
emission factors, controls, spatial and temporal allocations, and
example calculations please refer to Appendix A1.  

For Base-Year Emission Inventory data please refer to Appendix A6.

Biogenic Emissions 

 

An important component of the inventory is biogenic emissions.  Biogenic
emissions are those resulting from natural sources. Biogenic emissions
are primarily VOCs that are released from vegetation throughout the day.
 Biogenic emissions of NOx include lightning and forest fires. EPA used
a biogenic computer model (BEIS3.12) to estimate biogenic emissions for
each county in the country for all twelve months of the year 2002. 

Emissions data for Cecil County, MD ozone non-attainment area counties
were acquired from the EPA website
(ftp://ftp.epa.gov/EmisInventory/2002finalnei/biogenic_sector_data/).
EPA has recommended that states use these emissions in case they do not
have their own estimated biogenic emissions. Cecil County, MD portion of
the Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ ozone
nonattainment area decided to use the inventories provided by the EPA.  

For Base-Year Emission Inventory data please refer to Appendix C1.

3.3 Emissions Trends 

Reviewing emissions trends is an excellent way of tracking air quality
progress and control measure progress.  The difficulties in trending
emissions are however significant.  Emission estimating methodologies
and emission estimating models change constantly and it is difficult to
compare decades worth of emissions data.  As these emission estimating
methodologies become more specific and more accurate emissions may go up
or down depending on the methodology.  In addition, increases in
population and economic growth tend to make trending difficult.  It is
important to note these issues when reviewing emissions trends over long
time periods.

The following emissions trends have been prepared to examine the
Maryland portion of the Philadelphia - Wilmington - Atlantic City, PA -
DE - MD - NJ ozone nonattainment area emissions over the past 30 years. 
The 1970’s and 1980’s data was extracted from the 1-hr ozone SIPs
developed in the 1990’s.  

 

 Figure 3.1 Point Source Emission Trends in Tons Per Day*

*As point source data became increasingly important in the 1990’s, the
data collection process for these sources became more rigid.  Overall
trends in point sources are difficult to gauge, as historic data was not
provided in detail to MDE.

  Figure 3.2 Area Source Emission Trends in Tons Per Day



 

Figure 3.3 Mobile Source Emission Trends in Tons Per Day

  Figure 3.4 Nonroad Source Emission Trends in Tons Per Day 

    Figure 3.5 All Sources Emission Trends in Tons Per Day 

4.0  The 2008 and 2009 Projected Inventories 	

Part II of EPA’s rule to implement the 8-hour NAAQS requires that
Cecil County achieve a 15% reduction by 2008 using reductions in either
VOC or NOx emissions or with any combination of the two.  Also an
inventory for the attainment year 2009 is required for the region.  The
reduction must be calculated from the anthropogenic emissions levels
reported in the 2002 Base-Year Inventory after those levels have been
adjusted to reflect the expected growth in emissions between 2002 and
2008.  The 2002 Base-Year Inventory is described in Chapter 3. This
chapter presents the 2008 and 2009 Projection Inventories, the
estimation of the levels of emissions to be expected in those years
before the consideration of emission controls.

The 2008 and 2009 projected inventories are derived by applying the
appropriate growth factors to the 2002 Base-Year Emissions Inventory.
EPA guidance describes four typical indicators of growth.  In order of
priority, these are product output, value added, earnings, and
employment. Surrogate indicators of activity, for example population
growth, are also acceptable methods.    

 

Maryland Department of Planning, Planning Data Services employment
projections and Cooperative Forecasting results (population and housing
projections), prepared and officially adopted by the Baltimore
Metropolitan Council (BMC) were used to project emissions from area
sources.  Projections for onroad emissions were developed using
MOBILE6.2 (January 2003) model (please see Appendix F for information on
mobile source emissions).

EPA’s nonroad model, NONROAD2005, was used for developing both 2008
and 2009 nonroad model inventories. BMC’s Round 6A Cooperative
Forecasting results, Maryland Department of Planning, Planning Data
Services projections and the Economic Growth Analysis System (EGAS)
model were used to project growth in the additional nonroad source
categories such as railroad locomotives, marine vessels and airports.
The Economic Growth Analysis System (EGAS) model was used to project
growth in point source emissions.    

4.1  Growth Projection Methodology 

 

The following sections describe the method followed to determine the
projected inventories for 2008 and 2009. 

 

Growth Projection Methodology for Point Sources: EGAS 

 

The growth in point source emissions is projected using EGAS version
5.0.  Point source emissions for 2002 are provided from the state data
sources and the model is run with the following options selected:
projections are run by Source Classification Code; the Bureau of Labor
Statistics national economic forecast; and the baseline regional
economic forecast.

For source category listings and descriptions, projection methods and
data sources, and surrogate growth indicators please refer to Appendix
B1.  

Point source emission projection data is contained in Appendix A2

Growth Projection Methodology for Quasi-Point Sources

Quasi-point sources will include all emissions at the facility
regardless of whether they are classified as point, area, nonroad, or
mobile source emissions.  These emissions are actual emissions reported
for the facilities.  

No quasi-point sources are located in Cecil County, MD.  

Growth Projection Methodology: Area Sources 

 

Base-year area source surrogate growth factors for 2002 were calculated
using 2002 population, household, and employment data.  Linearly
interpolating between 2000 and 2005 data produced the 2002 data. 
Dividing Round 6A population, household, and employment forecasts for
the analysis year by the derived 2002 values for the region produced the
growth factors for the periods of 2002 to 2008 and 2002 to 2009. 
Categories related to transport and storage of gasoline were grown using
projected vehicle miles traveled (VMT) for analyses years. Area
projection inventories are contained in Appendix B. The growth factors
used for the 2008 and 2009 projection years are presented in Tables 4-1
and 4-2.  The growth factors were applied to emissions categories by
specific jurisdictions.   

Table 4-1:  2002-2008 Growth Factors

Jurisdiction 	 

Employment 	 

Population 	 

Household13	 

VMT 

 Cecil County 	1.2247	1.0957	1.1181	1.1189



Table 4-2:  2002-2009 Growth Factors

Jurisdiction 	 

Employment 12	 

Population13	 

Household 13	 

VMT 14

 Cecil County	1.2636	1.1080	1.1359	1.1431



The 2008 and 2009 emissions for area sources are calculated by
multiplying the 2002 base-year area emissions by the above growth
factors for the appropriate year for each jurisdiction.  Each area
source category was matched to an appropriate growth surrogate based on
the activity used to generate the base-year emission estimates.
Surrogates were chosen as follows: 

 

Surface Coating – depending on whether emission factors were based on
employment or population, surrogate chosen varied with individual
sub-categories. For example, automobile refinishing category was grown
using employment as the emission factor was based on it, but population
was chosen for growing traffic markings as its emission factor was based
on population.  

 

Commercial/Consumer Solvent Use - population was chosen as the growth
surrogate since 2002 emissions are based on per capita emission factors.


 

Residential Fuel Combustion – households was chosen as the growth
surrogate.  

Industrial/Commercial/Institutional Fuel Combustion - employment was
chosen as the growth surrogate except for the commercial/institutional
coal combustion category, where no growth was assumed. 

 

Vehicle Fueling (Stage II) and Underground Tank Breathing - all gasoline
marketing categories were based on vehicle miles traveled (VMT) data
since VMT is an appropriate surrogate for gasoline sales. Emission
factors for these categories are based on gasoline sales. 

 

Open Burning - population was chosen as the growth surrogate as yard
wastes, land debris, etc. increase with population. 

 

Structural Fires, Motor Vehicle Fires – population was chosen as the
growth surrogate.  

 

Publicly Owned Treatment Works (POTW) – households was chosen as the
growth surrogate.  

 

Dry Cleaning - population was chosen as the surrogate. 

 

Graphic Arts - population was used to estimate growth since emissions
are based on per capita emission factors. 

 

Surface Cleaning - employment growth was used as the surrogate. 

 

Tank Truck Unloading –growth in VMT was applied to this category since
base-year emissions are calculated using gasoline sales. 

 

Municipal Landfills - Base-year emissions are estimated using data on
total refuse deposited.  Population was chosen as a surrogate since
deposited waste is from the general population rather than industrial
facilities. 

 

Asphalt Paving - population was chosen as the surrogate since base-year
emissions are calculated using per capita emission factors. 

 

Bakeries, Breweries - population was chosen as the surrogate. 

 

Soil/Groundwater Remediation - zero growth was applied to this category.
 The number of remediations during the ozone season, used to generate
base-year emissions, does not directly correlate to population,
households, or employment growth.   

 

General Aviation and Air Taxi Emissions - Emissions from small airports
were projected using the EGAS 5.0 model.  

 

Aircraft Refueling Emissions - emissions from refueling of aircrafts was
projected based on employment.  

 

Portable Fuel Container Emissions - emissions from portable fuel
containers were grown based on population. 

 

Railroad Locomotives - employment growth was used as the surrogate. 

 

Forest Fires, Slash Burning, Prescribed Burning – zero growth was
applied to this category.  

 

Accidental Oil Spills - zero growth was applied to this category. 

 

Incineration– zero growth was applied to this category. 

 

Pesticide Application - zero growth was applied to this category. 

For source category listings and descriptions, projection methods and
data sources, and surrogate growth indicators please refer to Appendix
B1.  

Area source emission projection data is contained in Appendix A4.

Growth Projection Methodology: Nonroad Sources 

 

The 2008 and 2009 nonroad source inventories were created through the
use of EPA’s NONROAD2005.1.0 model (dt. 06/12/2006), except for
locomotives, marine diesel vessels, and aircrafts. The base year 2002
nonroad source inventory was created using NONROAD2005.0.0 model (dt.
12/02/2005). Since the time it was first issued on 12/02/2005, this
model version underwent several corrections. The base year nonroad
inventory was created using the version current as of 3/21/2006.  

The two model versions (NONROAD2005.0.0 and NONROAD2005.1.0) differ only
in the options provided in their graphic user interfaces (GUI) and not
in emission factors, base year equipment population, activity, load
factor, average lifetime, scrappage function, growth estimates, and
geographic and temporal allocation for any nonroad equipment and engine.
Therefore, emissions produced by the two versions for a particular
county, month, season, or year are the same.  

 

Nonroad model runs were made Cecil County, Maryland for an average ozone
season day. First the model was run for the entire summer season
(June-August) and then total emissions calculated this way was divided
by the total number of days (92) in the season to get an average ozone
season day emissions. Since ozone season extends from May through
September, monthly fuel data was averaged for this period to get fuel
parameters reflecting the ozone season period. These ozone season
averaged fuel parameters were then used in the above mentioned ozone
season runs for the region. 

   

Methodology to prepare inputs for the ozone season day is provided
below. 

 

Temperature: 

Temperature data was acquired from the National Climatic Data Center
(NCDC). Hourly average temperature data were collected for Baltimore
Washington International (BWI) station for the top ten 8-hour maximum
ozone days between 2002-2004. Then minimum, maximum, and average
temperatures were computed from this hourly temperature dataset.  

 

Fuel inputs: 

Month specific data for fuel RVP and oxygen weight percent were
collected from the MDE Mobile Source Division. The data was averaged for
the period May through September to get ozone season average inputs.
Model defaults were used for gas, diesel, marine diesel, and CNG/LPG
sulfur percent.  Stage II controls of zero percent was assumed for the
model runs. 

  

Model inputs (temperature, fuel, and other parameters) for both 2008 and
2009 are listed below: 

NONROAD Model Inputs

 

Parameters 	2008 Values 	2009 Values 

Min. Temperature 	65.55	65.55

Max. Temperature 	87.6	87.6

Avg. Temperature 	76.8	76.8

Reid Vapor Pressure (RVP) 	6.6	6.6

Gas Sulfur (%) 	0.003	0.003

Diesel Sulfur (%) 	0.0348	0.0348

Marine Diesel Sulfur (%) 	0.0408	0.0408

CNG/LPG Sulfur (%) 	0.003	0.003

Oxygen Weight (%) 	2.0	2.0

Stage II Control (%) 	0	0



Since the nonroad model does not generate emissions for aircraft, APU,
locomotives, and commercial diesel marine vessels, these were either
projected from the base year emissions using the BMC Round 6A
Cooperative Forecast or the EGAS model. Below are the details for
projecting emissions for the above mentioned individual nonroad
categories.  

 

Aircraft emissions (military, commercial, general aviation, air taxi)

 

Aviation emissions from small airports were projected using the EGAS 5.0
model.  

 

Ground support equipment emissions  

The NONROAD2005.1.0 model generated these emissions for small airports. 
The Nonroad model calculates emissions based on GSE population only. 

 

Commercial Diesel Marine Vessels 

Base year emissions from commercial diesel marine vessels were grown to
future years using employment as the surrogate. 

 

Railroad 

Railroad or locomotive emissions were grown using employment as the
surrogate. 

For source category listings and descriptions, projection methods and
data sources, and surrogate growth indicators please refer to Appendix
B1.  

Nonroad mobile source emission projection data is contained in Appendix
A6.

Growth Projection Methodology: Onroad Sources 

 

The 2008 and 2009 mobile source inventories were created through the use
of several models including Mobile6.2, the Highway Performance
Monitoring System (HPMS), and a transportation model described in the
appendix of this report.  A full description of this mobile emission
estimating process can be found in Appendix F of this report.

Biogenic Emission Projections 

 

Biogenic emission inventories for 2009 are the same as those used for
the 2002 base year for Cecil County. Year specific biogenic inventories
for 2009 were not estimated. 2002 base year emissions were estimated by
EPA using BEIS3.12 model. No 2008 biogenic inventories were prepared as
they are not used to determine rate of progress.  

4.2  Offset Provisions, Emission Reduction Credits and Point Source
Growth 

 

The Act requires that emission growth from major stationary sources in
nonattainment areas be offset by reductions that would not otherwise be
achieved by other mandated controls.  The offset requirement applies to
all new major stationary sources and existing major stationary sources
that have undergone major modifications.  Increases in emissions from
existing sources resulting from increases in capacity utilization are
not subject to the offset requirement.  For the purposes of the offset
requirement, major stationary sources include all stationary sources
exceeding an applicable size cutoff.  The NSR thresholds for Cecil
County are 25 tpy VOC and 25 tpy NOx.  

EPA has issued guidance on the inclusion of emission reduction credits
in the projected emissions inventory.  The guidance states “The base
year inventory includes actual emissions from existing sources and would
not normally reflect emissions from units that were shutdown or
curtailed before the base year (2002), as these emissions are not “in
the air” for purposes of demonstrating attainment, they must be
specifically included in the projected emissions inventory used in the
attainment demonstration along with other growth in emission over the
base year inventory.  This step assures that emissions from shutdown and
curtailed units are accounted for in attainment planning.”   Emission
reduction credits are included in a revised attainment demonstration
projected inventory.  A list of these emission reduction credits and
associated facilities is shown in Table 4.2.1.

Table 4.2.1 Emission Reduction Credits

Facility Name	State 

Facility Identifier	Pollutant Code	Emission Reduction Credits (TPY)

Bethlehem Steel	005-0147	NOX	701

Pulaski Incinerator	510-0498	NOX	302

Quebecor Printing	003-0274	NOX	2

G. Heileman Brewing (Strohs)	005-0129	NOX	24

Grief Brothers Corp.	005-0134	NOX	1

U.S.Can - Sparrows Pt. (Amer Nat)	005-0183	NOX	7

TPS Technologies, Inc. -Todd's La.	005-2131	NOX	16

Simpkins Industries - River Rd	027-0005	NOX	87

General Electric	027-0020	NOX	82

Alltrista Metal Services	510-0508	NOX	2

Trigen (Leadenhall St)	510-2796	NOX	33

Chevron Asphalt	510-0072	NOX	49

Coca Cola	510-0242	NOX	5

Crown Cork & Seal - Duncanwood	510-0320	NOX	10

Gordon D. Garratt	510-0360	NOX	1

Proctor & Gamble	510-0185	NOX	12

Schluderberg-Kurdle	510-0283	NOX	19

(Westport 510-0006 & Riverside 005-0078)	510-0006	NOX	1480

Giant - Bakery  (930 King St)	031-0224 	NOX	2

Armco Stainless/	510-0340	NOX	16

Bausch & Lomb	023-0019	NOX	1

Rohr Industries	043-0104	NOX	6

Showell Farms	047-0036	NOX	8

WR Grace	510-0076	NOX	17

General Motors - Truck & Bus	510-0354	NOX	119

Andrews Air Force Base	033-0655	NOX	15

Millenium Inorganic Chemicals	510-0109	NOX	30

Quebecor Printing 	003-0274	VOC	322

Bethlehem Steel	005-0147	VOC	0

Pulaski Incinerator	510-0498	VOC	11

BARCO - Fairlawn	510-2854	VOC	5

Crown Cork & Seal - Duncanwood	510-0320	VOC	13

Giant - Bakery  - 930 King St	031-0224  	VOC	0

Cello Professional Products	025-0145	VOC	0

Grief Brothers Corporation	005-0134	VOC	0

General Motors - Truck & Bus	510-0354	VOC	0

General Motors - Electromotive	005-0692	VOC	15

Crown Central Petroleum	003-0234	VOC	21

BGE - SNG Plant	005-1054	VOC	7

Ecko-Glaco Ltd.	005-0310	VOC	27

G. Heileman Brewing Co. (Strohs)	005-0129      	VOC	48

Maryland Paper Box	005-2220	VOC	15

Schlumberger Malco, Inc.	005-1614	VOC	12

U.S.Can-Sparrows Pt. (Amer Nat)	005-0183	VOC	90

TPS Technologies (Todd's La.)	005-2131	VOC	4

Simpkins Industries  (River Rd)	027-0005	VOC	7

3M Commercial Graphics	013-0052	VOC	30

Blue Chip Products	015-0058	VOC	35

Baycraft Fiberglass Engineering	025-0231	VOC	10

Alltrista Metal Services	510-00508	VOC	11

Armco/Balto. Specialty Steel	510-0340	VOC	11

CE Stevens Packaging  (printer)	510-2900	VOC	10

Chevron Asphalt	510-0072	VOC	2

Conoco Sun Gasoline Terminal	510-0676	VOC	27

Bata Shoe 	025-0003	VOC	18

Cherokee Sanford	033-0565	VOC	0

PPG Industries	001-0005	VOC	28

Tidewater Industrial Corp.	011-0039	VOC	11

Crown Cork & Seal - Hurlock	019-0073	VOC	96

Mail-Weil Graphics	019-0097	VOC	8

Metalfab - Grove Road	021-0317	VOC	11

Bausch & Lomb	023-0019	VOC	16

American Mouldings	043-0191	VOC	69

Carpenter Insulation	043-0189	VOC	146

CSX Minerals	043-0110	VOC	10

Rohr Industries	043-0104	VOC	4

Constellation - Westport 510-0006 & Riverside 005-0078	510-0006	VOC	23

Thomas Mfg.	005-0240	VOC	22

LeSaffre Yeast	510-0191	VOC	179



4.3  Actual vs. Allowable Emissions in Development of the 2008 and 2009
Projected Emissions Inventories 

  

To simplify comparisons between the base-year and the projected year,
EPA guidance states that comparison should be made only between like
emissions:  actual to actual, or allowable to allowable, not actual to
allowable.  Therefore, all base-year and all projection-year emissions
estimates are based on actual emissions.   

 

The term "actual emissions" means the data was directly provided by the
registered sources via annual emission certification reports.  Actual
emissions are calculated using the source's operating hours, production
rates, and types of material processed, stored, or combusted during the
selected time period.  

 

"Allowable emissions" are defined as the maximum emissions a source or
installation is capable of discharging after consideration of any
physical, operations, or emissions limitations required by state
regulations or by federally enforceable conditions, which restrict
operations and which are included in an applicable air quality permit to
construct or permit to operate, secretarial order, plan for compliance,
consent agreement, court order, or applicable federal requirement.   

 

4.4  Projection Inventory Results  

 

Chapter 6 of this SIP describes the control measures that have been or
will be implemented by 2008 and 2009 that will reduce emissions.  Most
control measures are required by federal or state regulations.  
Projected controlled inventories for 2008 and 2009 assume a number of
control measures to be in place by these years as identified in Chapter
6. 

 

Tables 4-3 and 4-4 present the projected controlled emissions for the
2008 rate-of-progress and 2009 attainment years resulting from
implementation of the control measures. 

4.5  2008 Controlled Emissions for Rate-of-Progress 

 

The projection of 2008 controlled emissions is simply the 2008
uncontrolled emissions minus the emission reductions achieved from the
federal control measures and the rate-of-progress control measures
implemented by states for the 8-hour ozone plan. This information is
presented in Tables 4-3 and 4-4. Controlled inventories are contained in
Appendix C1.  Details on mobile source emissions can be found in
Appendix F. 



Table 4-3:

2008 Projected Controlled VOC & NOx Emissions (tons/day)

MD Portion of the Philadelphia - Wilmington - Atlantic City, PA - DE -
MD - NJ Area

Emission Source

Category	Cecil County

VOC Emissions

(tons per day)	Cecil County

NOx Emissions

(tons per day)

Point	0.39	0.02

Area	4.75	0.23

Non-road	7.23	2.87

Mobile	2.29	7.93

Total	14.65	11.05



4.6  2009 Controlled Emissions for Attainment 

 

The projection of 2009 controlled emissions is simply the 2009
uncontrolled emissions minus the emission reductions achieved from the
federal control measures and the rate-of-progress control measures
implemented by states for the 8-hour ozone plan. 

Table 4-4:

2009 Projected Controlled VOC & NOx Emissions (tons/day)

MD Portion of the Philadelphia - Wilmington - Atlantic City, PA - DE -
MD - NJ Area

Emission Source

Category	Cecil County

VOC Emissions

(tons per day) 7	Cecil County

NOx Emissions

(tons per day) 8

Point	0.40	0.02

Area	4.57	0.24

Non-road	7.23	2.81

Mobile	2.20	7.6

Total	14.40	10.66



5.0 2008 Reasonable Further Progress Requirements 

5.1  Introduction 

 

In June 2005 EPA revoked the 1-hour ozone standard and published
implementation guidance for the 8-hour ozone standard. Cecil County was
classified as a moderate nonattainment of the 8-hour ozone standard. EPA
classified the Philadelphia - Wilmington - Atlantic City, PA - DE - MD -
NJ ozone nonattainment area (Philadelphia NAA) as a moderate area under
Subpart 2 area of Section 182 part b. 

As part of a moderate nonattainment area, EPA requires Cecil County to
demonstrate Reasonable Further Progress towards attainment by 2008. 
EPA’s implementation guidance requires that a moderate ozone
nonattainment areas, such as Cecil County, with an approved 15% VOC
reduction plan for the period 1990-1996 (required for former 1-hour
ozone non-attainment areas) demonstrate a 15% Reasonable Further
Progress for VOC and NOx by 2008. This chapter contains Cecil County’s
reasonable further progress demonstration for the years 2002-2008. Cecil
County will need to fulfill the 2002-2008 reasonable further progress
requirements by January 1, 2009.  

 

In order to demonstrate reasonable further progress, a region must show
that its expected emissions, termed controlled inventories, of NOx and
VOC will be less than or equal to the target levels set for the end of
the reasonable further progress period, or “milestone year”.  For
the RFP period 2002-2008, the “target inventories” of emissions are
the maximum quantity of anthropogenic emissions permissible during the
2008 milestone year. 

 

This section describes the methodology used to establish the regional
target inventories and controlled inventories for 2008.  Because the
expected NOx and VOC emissions will be less than or equal to the target
levels, Cecil County will meet the reasonable further progress
requirements for 2008. 

 

Rate of Progress Demonstrated in Previous State Implementation Plans 

 

Since 1990, the Clean Air Act has required ozone nonattainment areas to
demonstrate progress towards attaining the ozone standard. This
requirement is referred to as the reasonable further progress (RFP) or
reasonable further progress requirement. During the period 1990-1996,
areas in nonattainment for the one-hour ozone standard were required to
reduce VOC emissions by 15%. Since 1996, regions have been required to
demonstrate a 9% rate of progress every three years until the region’s
attainment date.  

 

The CAA included restrictions on the use of control measures to meet the
15% requirements. Reductions in ozone precursors resulting from four
types of federal and state regulations could not be used to meet rate of
progress. These four types of programs are:  

(1) 	Federal Motor Vehicle Control Program (FMVCP) tailpipe and
evaporative standards issued in January 1, 1990, 

(2) 	Federal regulations limiting the Reid Vapor Pressure (RVP) of
gasoline in ozone nonattainment areas issued by June 15, 1990; 

(3)	State regulations correcting deficiencies in reasonably available
control technology (RACT) rules 

(4) 	State regulations establishing or correcting inspection and
maintenance (I/M) programs for on-road vehicles.  

 

The basic procedures of developing target levels for the 15% Plan are
describe in EPA’s guidance on the Adjusted Base Year Emissions
Inventory and the 1996 Target for the 15% Rate of Progress Plans. 

 

5.2  Guidance for Calculating Reasonable Further Progress (RFP) Emission
Target Levels 

 

The Clean Air Act Amendments (CAAA) of 1990 provide the primary guidance
for calculating the VOC and NOx target levels used in a region’s
reasonable further progress (RFP) plans. In November 2005 as part of its
final implementation rule for the 8-hour ozone standard, EPA issued
guidance to assist the states in RFP development. 

  

The guidance that applies to the Cecil County, Maryland area is guidance
for previously severe 1-hour ozone nonattainment areas with an approved
15% Reasonable further progress plan for the period 1990-1996. Since the
Cecil County, Maryland region is a former severe 1-hour ozone
nonattainment area and has an approved 15% ROP plan for the above
period, “Method 2” of the guidance applies to the region.   The
region is required to reduce emissions by 15% from 2002-2008 to
demonstrate Reasonable Further Progress, according to Method 2. 

 

EPA’s guidance (Method 2) states that the target level of VOC and NOx
emissions in 2008 needed to meet the 2008 ROP requirement is any
combination of VOC and NOx reductions from the adjusted base year 2002
inventories (base year 2002 emissions less non-creditable emissions
reduction occurring between 2002 and 2008) that total 15%. For example,
the target level of VOC emissions in 2008 could be a 10% reduction from
the adjusted base year 2002 VOC inventory and a 5% reduction from the
adjusted NOx inventory. The actual projected 2008 VOC and NOx
inventories for all sources with all control measures in place and
including projected 2008 growth in activity must be at or lower than the
target levels of VOC and NOx emissions. The actual projected 2008 VOC
and NOx inventories for all sources with all control measures in place
and including projected 2008 growth in activity must be at or lower than
the target levels of VOC and NOx emissions.

 

This section briefly summarizes the requirements and procedures for
calculating the target emission levels required for a RFP demonstration.
RFP demonstrations build upon each other, starting from the base year of
2002.  

 

2008 VOC and NOx Target Levels 

 

EPA’s Final Rule To Implement the 8-Hour Ozone National Ambient Air
Quality Standard – Phase II mandates that to meet the reasonable
further progress requirement, the Cecil County, MD portion of the
Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ ozone
nonattainment area ozone nonattainment area needs to reduce its
emissions by 15% between 2002 and 2008 using either reduction in VOC or
NOx or any combination of the two.  The Cecil County, MD portion of the
Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ ozone
nonattainment area is able to demonstrate reasonable further progress
for the period 2002-2008 using 15% VOC reduction.  

 

The target levels for 2008 reasonable further progress plans are
calculated according to the EPA’s final rule mentioned above. The
general formula for calculation of 2008 target levels is as follows: 

Equation: 5-6

Target Level	=	RFP base year emissions	-	reductions required to meet the
reasonable further progress requirement	-	non-creditable emissions
reduction between 2002 and 2008



Calculation of 2008 Target Levels 

 

Equation 5-6 gives the general formula for calculating post-1996 target
levels. Since the region has chosen to demonstrate the 2008 reasonable
further progress using 15% VOC reduction, the 2008 VOC target level
becomes: 

Equation: 5-7

2008 VOC Target Level	=	2002 RFP Base-Year emissions	-	7.5% VOC
Reduction	-	non-creditable emissions reduction between 2002 and 2008



Equation: 5-8

2008 NOx Target Level	=	2002 RFP Base-Year emissions	-	7.5% NOx
Reduction	-	non-creditable emissions reduction between 2002 and 2008



Step 1  Develop 2002 Base Year Inventories and 2002 Reasonable Further
Progress Base Year Inventories 

 

The 2002 base year inventory is an inventory of actual anthropogenic and
biogenic VOC emissions on a typical weekday during peak ozone season.
The inventory was calculated as described in Chapter 3 and is presented
in Table 3-1. The reasonable further progress base-year inventory
includes only anthropogenic emissions generated within the Cecil County,
MD portion of the Philadelphia - Wilmington - Atlantic City, PA - DE -
MD - NJ ozone nonattainment area. As the 2002 base-year inventory
included no emissions generated outside the Cecil County, MD area, the
only difference between the base year inventory and the reasonable
further progress base year inventory is the removal of biogenic
emissions. The reasonable further progress base year VOC inventory is
presented in Table 5-1.  

 

Table 5-1 

2002 Reasonable Further Progress Base-Year Inventory

(Ozone Season tons per day)

Source	VOC	NOx

Point 	0.28	0.02

Area 	4.93	0.20

Non-Road 	8.37	2.97

On-Road 	4.00	14.22

TOTAL 	17.58	17.40

Note: Small discrepancies may result due to rounding 

 

Step 2 Develop 2002 and 2008 Reasonable Further Progress Adjusted Year
Inventories 

 

According to the 1990 CAAA, reductions necessary to meet the reasonable
further progress requirement must be calculated from an emission
baseline that excludes the effects of the non-creditable Federal Motor
Vehicle Control Program (FMVCP) and Reid Vapor Pressure (RVP) programs
described in Section 5.2. Therefore the 2002 baseline must be adjusted
by subtracting the VOC and NOx reductions that will result from these
two programs between 2002 and 2008. The resulting inventory is referred
to as the 2002 Adjusted Base Year Inventory. 

 

In order to calculate the non-creditable emissions reductions, which
occur between 2002 and 2008, the following two mobile inventories are
needed: 

 

1) 2002 Reasonable Further Progress Adjusted-Year Inventory 

2) 2008 Reasonable Further Progress Adjusted-Year Inventory 

 

Both of these mobile inventories were created using the same inputs
(listed below), with the only difference between them being the
automobile model year (inventory #1 and #2 were created for 2002 and
2008 respectively).  

 

a) 1990 I/M Program 

b) RVP = 7.8 psi (RVP required according to June 1990 fuel RVP
regulations) 

c) No Post-1990 Clean Air Act Measures 

d) 2002 Vehicle Activity Inputs 

e) 2002 Vehicle Miles Traveled (VMT) 

 

The MOBILE6 input files are included in Appendix F. Table 5-2 & 5-3 show
RFP adjusted-year inventories for 2002 and 2008 respectively. 

Table 5-2

2002 Reasonable Further Progress Adjusted-Year Inventory 

(Ozone Season tons per day) 

Source	VOC	NOx

Point 	0.28	0.02

Area 	4.93	0.20

Non-Road 	8.37	2.97

On-Road 	5.42	16.09

TOTAL 	19.00	19.28

Note: Small discrepancies may result due to rounding 

 



Table 5-3

2008 Reasonable Further Progress Adjusted-Year Inventory 

(Ozone Season tons per day) 

Source	VOC	NOx

Point 	0.28	0.02

Area 	4.93	0.20

Non-Road 	8.37	2.97

On-Road 	4.73	13.90

TOTAL	  =SUM(ABOVE) \# "#,##0.00"    18.31 	  =SUM(ABOVE) \# "#,##0.00" 
  17.09 

Note: Small discrepancies may result due to rounding 

 

 

Step 3  Non-creditable Emissions Reductions  

 

The non-creditable emissions reductions that occur in absence of any
post-1990 CAA measures during a reasonable further progress period can
be determined by taking the difference between the RFP adjusted-year
inventories for the relevant milestone years. For VOC and NOx, the
relevant milestone years are 2002 and 2008. 

Equation: 5-9

Non-creditable Emissions Reductions	=	2002 RFP Adjusted Year Inventory	-
2008 RFP Adjusted Year Inventory



Table 5-3

Calculation of Non-creditable Emissions Reductions

(Ozone Season tons per day)

Description 	VOC	NOx

2002 Adjusted Year Inventory (a) 	5.42	16.09

2008 Adjusted Year Inventory (b) 	4.73	13.90

Non-creditable Emissions Reduction (a-b)	  =B2-B3 \# "#,##0.00"     0.69
	  =C2-C3 \# "#,##0.00"     2.19 



Step 4  Calculation of 2008 Target Levels 

 

Following Equations 5-7, 5-8 and 5-9, the VOC and NOx target levels for
2008 are calculated in Table 5-4 below:  

Table 5-4

Calculation of VOC and NOx Target Levels for 2008 

(Ozone Season tons per day) 

 	 Description	Formula	VOC	NOx

A	2002 Base Year Inventory

60.52	17.40

B	Biogenic Emissions

42.94	0.00

C	2002 Rate-of Progress Base Year Inventory	A - B	17.58	17.40

D	FMVCP/RVP Reductions Between 2002 and 2008

0.69	2.19

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
16.89	15.21

F	Ratio

0.07	0.08

G	Emissions Reductions Required Between 2002 and 2008	E * F	1.18	1.22

H	Target Level for 2008  [TL(2008)]	C - D - G	15.71	13.99



  

5.3  Compliance with 2008 Reasonable Further Progress Requirements 

 

In order to demonstrate reasonable further progress for the period
2002-2008, the Cecil County, MD portion of the Philadelphia - Wilmington
- Atlantic City, PA - DE - MD - NJ ozone nonattainment area must show
that expected emissions in 2008 are equal to or less than the 2008
target levels presented in Table 5-4.  

 

The 2008 controlled inventories are inventories of all anthropogenic VOC
and NOx emissions expected to occur in Cecil County, MD during 2008. The
inventories were developed as described in Chapter 4 and are displayed
in Tables 4-3 and 4-4. As summarized in Table 5-5, the 2008 controlled
VOC and NOx inventories are less than the 2008 target inventories. Table
5-5 demonstrates that the Cecil County, MD area of the Philadelphia -
Wilmington - Atlantic City, PA - DE - MD - NJ ozone nonattainment area
fulfills the 2002-2008 reasonable further progress requirements. 

 

Table 5-5

Comparison of 2008 Controlled and Target Inventories 

Ozone Season Daily Emissions (tons per day) 

Description 	VOC	NOx

2008 Target Levels 	15.71	13.99

2008 Controlled Emissions 	14.59	11.05



References 

 

U.S. EPA, “Guidance on the Adjusted Base Year Emissions Inventory and
the 1996 Target for the 15% Rate of Progress Plans” 

 

U.S. EPA, “Guidance on the Post-1996 Reasonable Further Progress Plan
and the Attainment Demonstration”, February 18, 1994. 

 

U.S. EPA, “NOx Substitution Guidance”, December 1993. 

6.0  Control Measures	

This chapter is divided into three sections.  Section 6.1 identifies the
control measures that were part of the 1-Hour Ozone SIP for Cecil
County, Maryland.  These regulations/ control measures continue to be in
existence and continue to reduce emissions in the region.  All of the
emission reductions from the measures identified in Section 6.1 were
part of the baseline emission inventory for Cecil County, Maryland.

Section 6.2 of this chapter identifies measures implemented after 2002
that were not part of the baseline inventory and are giving specific
emission reductions to the region’s 8-hour Ozone reasonable further
progress demonstration.  

Section 6.3 identified voluntary/ innovative measures that the Maryland
is not taking formal credit for in the SIP.  These measures are not
commitments to programs but present information on programs that are
directionally correct and could provide ozone benefits.

6.1  1-Hour Ozone Control Measures

On-Road Mobile Measures

Enhanced Vehicle Inspection and Maintenance (Enhanced I/M)

The Clean Air Act requires enhanced motor vehicle inspection and
maintenance (I/M) programs in serious, severe, and extreme ozone
nonattainment areas and MSA/CMSA portions of the OTR with urbanized
populations over 200,000.  In Maryland, this required enhanced I/M
program in the eight jurisdictions operating a basic I/M program as well
as six new jurisdictions, for a total of 14 of the 23 jurisdictions in
the state.   Tailpipe emissions are measured over a transient driving
cycle conducted on a dynamometer, which provides a much better
indication of actual on-road vehicle performance than the existing idle
test.  

Tier I Vehicle Emission Standards and New Federal Evaporative Test
Procedures

The Act requires a new and cleaner set of federal motor vehicle
emissions standards (Tier I standards) beginning with model year 1994. 
The Act also requires a uniform level of evaporative emission controls,
which are more stringent than most evaporative controls used in existing
vehicles. These federally implemented programs affect light duty
vehicles and trucks.

	

Reformulated Gasoline in On-road Vehicles

All gasoline-powered vehicles are affected by this control measure. 
Vehicle refueling emissions at service stations are also reduced.  In
addition, emissions from gasoline powered nonroad vehicles and equipment
will be reduced by this control strategy.  Since January of 1995, only
gasoline that the EPA has certified as reformulated may be sold to
consumers in the nine worst ozone nonattainment areas with populations
exceeding 250,000.

National Low Emission Vehicle Program

The NLEV program is a vehicle technology program that provides light
duty vehicles and trucks that are significantly cleaner than pre-1998
models. The National LEV program was developed through an unprecedented,
cooperative effort by the northeastern states, auto manufacturers,
environmentalists, fuel providers, U.S. EPA and other interested
parties.  National LEV vehicles are 70% cleaner than 1998 models. The
National LEV program will result in substantial reductions in volatile
organic compounds (VOCs) and oxides of nitrogen (NOx), which contribute
to unhealthy levels of smog in many areas across the country.  		

Tier 2 Vehicle Emission Standards

In 1999, EPA proposed more stringent tailpipe emissions standards for
cars and light trucks weighing up to 8,500 pounds.  Commonly referred to
as Tier 2, these standards take effect beginning in 2004 when
manufacturers start producing passenger cars that are 77 percent cleaner
than those on the road today.  Light-duty trucks, such as SUVs, which
are subject to standards that are less protective than those for cars,
would be as much as 95 percent cleaner under the new standards.  

Federal Heavy-Duty Diesel Engine Rule

EPA’s heavy-duty engines rule will address diesel vehicles weighing
more than 8,500 pounds, These standards will take effect in 2007 and
reduce emissions from new HDDEs by 95%.  In order to achieve the new
standards, ultra-low sulfur diesel fuel will be needed. 

Stage II Recovery Systems

This measure required the installation of Stage II vapor recovery
nozzles at gasoline pumps.  Maryland adopted Stage II vapor recovery
regulations for the Baltimore and Washington nonattainment areas and
Cecil County in January of 1993. The Stage II vapor recovery regulation
requires that the dispensing system be equipped with nozzles that are
designed to return the vapors through a vapor line into the gasoline
tank.

 New Vehicle On-Board Vapor Recovery Systems

This measure required the installation of onboard refueling emissions
controls for new passenger cars and light trucks beginning in the 1998
model year.  The onboard refueling vapor recovery (ORVR) system was
required for new passenger cars and light trucks beginning in model
1998.

Area Source Measures

VOC Controls in Maryland

Automotive and Light-Duty Truck Coating

Can Coating		

Coil Coating		

Large Appliance Coating	

Paper, Fabric, Vinyl, and Other Plastic Parts Coating

Control of VOC Emissions from Solid Resin Decorative Surface
Manufacturing

Metal Furniture Coating	

Control of VOC Emissions from Cold and Vapor Degreasing

Flexographic and Rotogravure Printing

Lithographic Printing 	

Dry Cleaning Installations	

Miscellaneous Metal Coating	

Aerospace Coating Operations

Brake Shoe Coating Operations

Control of Volatile Organic Compounds from Structural Steel Coating
Operations

Manufacture of Synthesized Pharmaceutical Products

Paint, Resin and Adhesive Manufacturing and Adhesive Application

Control of VOC Equipment Leaks

Control of Volatile Organic Compound (VOC) Emissions from Yeast
Manufacturing

Control of Volatile Organic Compound Emissions from Screen Printing and
Digital Imaging

Control of Volatile Organic Compounds (VOC) Emissions from Expandable
Polystyrene Operations

Control of Landfill Gas Emissions from Municipal Solid Waste Landfills

Control of Volatile Organic Compounds (VOC) Emissions from Commercial
Bakery Ovens

Control of Volatile Organic Compounds (VOC) from Vinegar Generators

Control of VOC Emissions from Vehicle Refinishing

Control of VOC Emissions from Leather Coating

Control of Volatile Organic Compounds from Explosives and Propellant
Manufacturing

Control of Volatile Organic Compound Emissions from Reinforced Plastic
Manufacturing

Control of Volatile Organic Compounds from Marine Vessel Coating
Operations

Control of Volatile Organic Compounds from Bread and Snack Food Drying
Operations

Control of Volatile Organic Compounds from Distilled Facilities

Control of Volatile Organic Compounds from Organic Chemical Production

Iron and Steel Production Installations

Control of Kraft Pulp Mill Emissions

Municipal Landfills

A municipal solid waste landfill is a disposal facility where household
waste is placed and periodically covered with inert material.  Landfill
gases are produced from the decomposition and chemical reactions of the
refuse in the landfill.  They consist primarily of methane and carbon
dioxide, with volatile organic compounds making up less than one percent
of the total emissions. The control strategy for this source category is
based upon federal rules.  

Burning Ban

August).  There are exemptions for agricultural burning, fire training
and recreational activities.  

Surface Cleaning/Degreasing

Cold degreasing is an operation that uses solvents and other materials
to remove oils and grease from metal parts including automotive parts,
machined products, and fabricated metal components.  MDE adopted
regulations in 1995 to require small degreasing operations such as
gasoline stations, autobody paint shops, and machine shops to use less
polluting degreasing solvents in serious and severe ozone nonattainment
areas. Also, solvent baths and rags soaked with solvents must be covered
under this regulation.

Architectural and Industrial Maintenance Coatings

Architectural and industrial maintenance coatings are field-applied
coatings used by industry, contractors, and homeowners to coat houses,
buildings, highway surfaces, and industrial equipment for decorative or
protective purposes.  VOC emissions result from the evaporation of
solvents from the coatings during application and drying. A federal
measure requires reformulation of architectural and industrial
maintenance coatings. The users of these coatings are small and
widespread, making the use of add-on control devices technically and
economically infeasible.  

Commercial and Consumer Products

Consumer and commercial products are items sold to retail customers for
household, personal or automotive use, along with the products marketed
by wholesale distributors for use in institutional or commercial
settings such as beauty shops, schools, and hospitals. VOC emissions
result from the evaporation of solvent contents in the products or
solvents used as propellants. This measure requires the reformulation of
certain consumer products to reduce their VOC content.  Product
reformulation can be accomplished by substituting water, other non-VOC
ingredients, or low-VOC solvents for VOCs in the product.

Automobile Refinishing 

Automobile refinishing is the repainting of worn or damaged automobiles,
light trucks, and other vehicles.    Volatile organic compound emissions
result from the evaporation of solvents from the coatings during
application, drying and clean up techniques. This measure based on state
regulation requires large and small autobody refinishing operations to
use low VOC content materials in the refinishing process and cleanup,
and to use efficient spray guns to control application. The Department
adopted regulations in 1995 requiring the use of reformulated coatings. 


Screen Printing

A screen-printing process is used to apply printing or an image to
virtually any substrate.  In the screen-printing operation, ink is
distributed through a porous screen mesh to which a stencil may have
been applied to define an image to be printed on a substrate.  VOC
emissions result from the evaporation of ink solvents and from the use
of solvents for cleaning. The major source of VOC emissions is the
printing process. This measure requires smaller printers to use water
based and/or low VOC materials to reduce VOC emissions. Because the
users of these coatings are relatively small, requiring the use of
add-on control devices is technically and economically infeasible. 
Reductions in VOC emissions were obtained through the use of ink
reformulation, process printing modification, and material substitution
for cleaning operations. This regulation became effective on June 5,
1995.

Graphic Arts – Lithographic Printing

This source category consists of numerous small sheet-fed printers that
perform non-continuous printing and web printers that print on a
continuous web or roll.  Heat-set web printers use drying ovens to force
dry the printed matter.  Web printing sources perform high volume
printing on paper or paperboard.  VOC emissions to the air are caused by
evaporation of the ink solvents, alcohol in the fountain or dampening
solution, and equipment wash solvents.  These VOC discharges may also
cause visible emissions and nuisance odors. MDE adopted a regulation in
1995 to require printers to use control devices and/or low VOC materials
to reduce VOC emissions.

Graphic Arts – Flexographic and Rotogravure Printing

This source category consists of numerous small flexographic or
rotogravure printers that perform non-continuous sheet fed printing and
continuous web or roll printing.  MDE adopted a printing regulation in
1987 that requires smaller printers to use control devices and/or low
VOC materials to reduce VOC emissions. VOC emissions to the air are
caused almost entirely by evaporation of the ink solvents. Although
several control devices were evaluated over the years for rotogravure
and flexographic web printers, a catalytic oxidizer has proven to be
most successful.  A typical oxidizer yields 96-98 percent destruction of
VOC.  Most sources were in compliance with all requirements by early
1992. 

Non-Road Measures

Nonroad Small Gasoline Engines

This measure requires small gasoline-powered engine equipment, such as
lawn and garden equipment, manufactured after August 1, 1996 to meet
federal emissions standards. Small gasoline-powered engine equipment
includes lawn mowers, trimmers, generators, compressors, etc. These
measures apply to equipment with engines of less than 25 horsepower. 
VOC emissions result from combustion and evaporation of gasoline used to
power this equipment.

Non-Road Diesel Engines Tier I and Tier II

This measure takes credit for NOx emissions reductions from emissions
standards promulgated by the EPA for non-road, compression-ignition
(i.e., diesel-powered) utility engines.  The measure affects
diesel-powered (or other compression-ignition) heavy-duty farm,
construction equipment, industrial equipment, etc., rated at or above 37
kilowatts (37 kilowatts is approximately equal to 50 horsepower).
Heavy-duty farm and construction equipment includes asphalt pavers,
rollers, scrapers, rubber-tired dozers, agricultural tractors, combines,
balers, and harvesters.  This measure applies to all
compression-ignition engines except engines used in aircraft, marine
vessels, locomotives and underground mining activity.  NOx emissions
result from combustion of diesel fuel used to power this equipment.

Marine Engine Standards

Of the nonroad sources studied by EPA, gasoline marine engines were
found to be one of the largest contributors of hydrocarbon (HC)
emissions (30% of the nationwide nonroad total). This measure controls
exhaust emissions from new spark-ignition (SI) gasoline marine engines,
including outboard engines, personal watercraft engines, and jet boat
engines. 

Emissions standards for large spark ignition engines

This EPA measure controls VOC and NOx emissions from several groups of
previously unregulated nonroad engines, including large industrial
spark-ignition engines, recreational vehicles, and diesel marine
engines.  The emission standards apply to all new engines sold in the
United States and any imported engines manufactured after these
standards begin. Controls on the category of large industrial
spark-ignition engines are first required in 2004.  Controls on the
other engine categories are required beginning in years after 2005. 
Large industrial spark-ignition engines are those rated over 19 kW used
in a variety of commercial applications; most use liquefied petroleum
gas, with others operating on gasoline or natural gas.  

Reformulated gasoline use in non-road motor vehicles and equipment

This federally mandated measure requires the use of lower polluting
"reformulated" gasoline in Cecil County.  The measure involves taking
credit for reductions due to the use of the reformulated gasoline in
non-road mobile sources.  Nonattainment areas classified as severe were
required to opt in on the delivery of reformulated gasoline.  This
measure affects the various non-road mobile sources that burn gasoline;
such as small gasoline-powered engine equipment includes lawn mowers,
trimmers, generators, compressors, etc.  VOC emissions result from
combustion and evaporation of gasoline used to power this equipment.

Railroad Engine Standards

This measure establishes emission standards for oxides of nitrogen
(NOx), hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM),
and smoke for newly manufactured and remanufactured diesel-powered
locomotives and locomotive engines, which have previously been
unregulated. This regulation took effect in 2000 and affects railroad
manufacturers and locomotive re-manufacturers.  It involves adoption of
three separate sets of emission standards with applicability dependent
on the date a locomotive is first manufactured.

Point Source Measures 

Expandable Polystyrene Products

     

These sources use expandable polystyrene beads that contain pentane, a
VOC, to manufacture foam products such as foam cups, board insulation,
and custom shapes. VOC emissions typically occur during storage and
pre-expansion of the beads, during manufacturing, and during "aging"
when the blowing agent (pentane) slowly diffuses from the foam before
shipping. This control measure requires RACT (Reasonably Available
Control Technologies) to be installed at operations that manufacture
foam cups, foam insulation and other foam products. The regulation
became effective in July 1995. 

Yeast Manufacturing

Yeast is produced using an aerated fermentation process under controlled
conditions.  In June 1995, MDE required RACT to be installed at two
yeast-manufacturing operations in the Baltimore nonattainment area.  The
regulation results in an overall emission reduction of approximately 60
to 70 percent from the 1990 baseline by requiring affected sources to
meet specific VOC emission standards.

Commercial Bakery Ovens

This measure requires commercial bakeries using yeast to leaven bread
and bread products to install RACT.  Commercial bakeries generate VOC
emissions from the fermentation and baking processes used to produce
yeast-raised baked goods.  These emissions are primarily ethanol.  The
regulation requires control equipment dependent upon thresholds that are
based on cost effectiveness criteria.  

Federal Air Toxics

This measure covers sources that are required to comply with Federal air
toxics requirements. The Department has delegation to implement Federal
air toxics rules that will achieve VOC emissions reductions.  Federal
rules that may achieve such reductions include Federal NESHAPs for vinyl
chloride production plants and benzene emissions from equipment leaks,
benzene storage vessels, coke by-product recovery plants, benzene
transfer operations and waste operations and the EPA Maximum Achievable
Control Technology (MACT) program.

Enhanced Rule Compliance

Enhanced Rule Compliance or rule effectiveness (RE) improvement refers
to an improvement in the implementation of and compliance with a
regulation.  These RE improvements may take several forms, ranging from
more frequent and in-depth training of inspectors to larger fines for
sources that do not comply with a given rule. 

State Air Toxics

This measure addresses stationary sources that are covered by Maryland's
air toxics regulations that have achieved VOC reductions above and
beyond current federally enforceable limits.  In general, Maryland's air
toxics regulations cover any source required to obtain a permit to
construct or annually renewed state permit to operate. The Department
adopted the air toxics regulations in 1988.  

NOx RACT -- Reasonably Available Control Technology

This measure requires control of nitrogen oxides (NOx) emissions by
installing RACT.  NOx RACT will apply to utility, industrial and
commercial fuel burning equipment and combustion installations. The
regulation established cost-effective controls on all installations
located at major NOx sources. This first phase of stationary source NOx
reductions resulted in an approximate 22% reduction in NOx emissions.

NOx Phase II/Phase III Ozone Transport Commission (OTC)/NOx Budget Rule
(Phase II) and NOx SIP Call (Phase III)

In 1994, the OTC member states signed a major agreement to reduce NOx
emissions from power plants and other major stationary sources of
pollution throughout the Northeast and Mid-Atlantic States.  The
agreement recognized that further reductions in NOx emissions are needed
to enable the entire Ozone Transport Region (OTR) to meet the NAAQS. The
Department adopted a “NOx Budget” rule to require a second phase of
stationary source NOx reductions as part of this regulatory initiative.
This regulation requires large stationary sources to reduce summertime
NOx emissions by approximately 65% from 1990 levels. The regulation also
includes provisions allowing sources to comply by trading
“allowances.” This regulation requires affected sources to have met
these requirements by May 2000.

In late 1998, the U.S. EPA adopted its “NOx SIP Call” to reduce
ozone transport in the Eastern United States. This regional NOx
reduction program requires 22 states, including Maryland, to submit
regulations and a revision to State Implementation Plans (SIPs) to
further reduce NOx emission by 2007. Maryland’s Phase III regulations
achieve approximately 23% additional reductions from large stationary
sources like power plants, cement kilns and large industrial boilers.
The regulations require affected sources to add specific control
equipment or to reduce emissions or trade to meet the allowable amount
("cap") of seasonal NOx emissions by 2003. 

6.2  8-Hour Ozone Control Measures

The following measures have been implemented in Maryland since 2002 (the
baseline emissions inventory year for 8-Hour Ozone).  These measures
were not part of the baseline emissions inventory for the 8-Hour Ozone
SIP and emission reductions from these measures were forecasted for both
2008 (reasonable further progress calculation) and 2009 (attainment
inventory) for use in the reasonable further progress calculations for
Cecil County as well as the attainment modeling for the region.  A
summary of the control measures and their benefits is presented in Table
6.1 below.  The benefits below summarize the emission credits available
from the listed measures based on the difference between a 2008/2009
controlled and uncontrolled inventory.

Table 6.1: Control Measures Summary



	2008

2009

Control Measure	VOC

(tpd)	NOx

(tpd)

VOC

(tpd)	NOx

(tpd)

Enhanced I/M





	Tier I





	Reform Gas





	LEV





	HDDE





	Total Mobile	1.75	3.78

1.85	3.78

Stage II/Refuel	0.00	0.00

0.00	0.00

OTC - Consumer Products Phase 1	0.14	0.00

0.14	0.00

OTC - Consumer Products Phase 2	0.00	0.00

0.02	0.00

OTC – AIM	0.39	0.00

0.39	0.00

OTC - PFC Phase 1	0.26	0.00

0.32	0.00

OTC - PFC Phase 2	0.00	0.00

0.03	0.00

OTC - Industrial Adhesives	0.00	0.00

0.10	0.00

Open Burning	0.00	0.00

0.00	0.00

Nonroad Model	1.18	0.28

1.50	0.36

Railroads (Tier 2)	0.00	0.15

0.00	0.16

Healthy Air Act (HAA)	0.00	0.00

0.00	0.00

Total	3.71	4.21

4.35	4.30



The Maryland Healthy Air Act (HAA)

In April of 2006, the Maryland General Assembly enacted the Maryland
Healthy Air Act. The Maryland General Assembly record related to the HAA
and the final version of the Act itself can be found at:
http://mlis.state.md.us/2006rs/billfile/SB0154.htm

The MDE Regulations (Code of Maryland Regulations) can be found at:

http://www.mde.state.md.us/assets/document/CPR_12-26-06_Emergency_and_Pe
rmanent_HAA_Regs_for_AELR.pdf

The HAA is one of the most stringent power plant emission laws on the
east coast.  The HAA requires reductions in Nitrogen Oxide (NOx), Sulfur
Dioxide (SO2) and Mercury emissions from large coal burning power
plants.  The Healthy Air Act also requires that Maryland become involved
in the Regional Greenhouse Gas Initiative (RGGI) which is aimed at
reducing greenhouse gas emissions.

The Maryland Department of the Environment (MDE) has been charged with
implementing the HAA through regulations. As enacted, these regulations
constitute the most comprehensive air pollution emission reduction
measure proposed in Maryland history.

Affected Sources

 

These Healthy Air Act NOx reduction requirements affect the following
fossil fuel fired electric generating units (only the Constellation
Energy Group Systems are located in the Baltimore Nonattainment Area):

Constellation Energy Group System

Brandon Shores 1 & 2 Anne Arundel County

H. A. Wagner 2 & 3 Anne Arundel County

C. P. Crane 1 & 2 Baltimore County

Mirant System

Chalk Point 1 & 2 Prince George’s County

Dickerson 1, 2, & 3 Montgomery County

Morgantown 1 & 2 Charles County

Allegheny Energy Washington County

R. Paul Smith, 3 & 4

Overview of Expected Emission Reductions

While none of the HAA affected sources are located in Cecil County,
Maryland, the MDE lists this important regulation in the SIP as emission
reductions from these upwind facilities will have a substantial impact
on the air quality in Cecil County. 

Over ninety-five percent of the air pollution emitted from Maryland’s
power plants comes from the largest and oldest coal burning plants.  The
emission reductions from the HAA come in two phases.  The first phase
requires reductions in the 2009/ 2010 timeframe and compared to a 2002
emissions baseline reduce NOx emissions by almost 70%, SO2 emissions by
80% and mercury emissions by 80%.

The second phase of emission control occurs in the 2012/ 2013 timeframe.
 At full implementation the HAA will reduce NOx emissions by
approximately 75% from 2002 levels, SO2 emissions will be reduced by
approximately 85% from 2002 levels, and mercury emissions will be
reduced by 90%.

  

Table 6.2 Annual Maryland Healthy Air Act NOx Emissions Reductions
(TPY):

Unit	2002 Emissions	Uncontrolled 2009 Emissions	2009 HAA Caps	2009 HAA
Emission Reductions	2009 HAA Emission Reduction %	2012 HAA Caps	2009
Uncontrolled Emissions - 2012 HAA Cap	2012 HAA Emission Reduction % 

Brandon Shores 1	6329	7558	2927	4631	61.27	2414	5144	68.06

Brandon Shores 2	6034	7206	3055	4151	57.60	2519	4687	65.04

Wagner 2	2232	2666	673	1993	74.76	555	2111	79.18

Wagner 3	1718	2052	1352	700	34.11	1115	937	45.66

Crane 1	6245	7458	832	6626	88.84	686	6772	90.80

Crane 2	4285	5117	894	4223	82.53	737	4380	85.60

TOTALS	26843	32057	9733	22324	69.64	8026	24031	74.96



Table 6.3 Ozone Season Maryland Healthy Air Act NOx Emissions
Reductions:

Unit	2002 Emissions (Ozone Season Day)	2002 Emissions (Ozone Season =
153 Days)	Uncontrolled 2009 Emissions (Ozone Season Day)	Uncontrolled
2009 Emissions (Ozone Season = 153 Days)	2009 HAA Caps (Ozone Season =
153 Days)	2009 HAA Emission Reductions (Ozone Season)	2009 HAA
Reductions (Tons per Ozone Season Day)	2012 HAA Caps (Ozone Season = 153
Days)	2009 Uncontrolled Emissions - 2012 HAA Cap (Ozone Season)	2009
Uncontrolled Emissions - 2012 HAA Cap (Tons Per Ozone Season day)

Brandon Shores 1	9.68	1481.04	11.56	1768.68	1363	405.68	2.65	1124	644.68
4.21

Brandon Shores 2	7.60	1162.80	9.08	1389.24	1449	-59.76	-0.39	1195	194.24
1.27

Wagner 2	6.88	1052.64	8.21	1256.13	278	978.13	6.39	229	1027.13	6.71

Wagner 3	3.28	501.84	3.91	598.23	583	15.23	0.10	481	117.23	0.77

Crane 1	11.86	1814.58	14.16	2166.48	345	1821.48	11.91	284	1882.48	12.30

Crane 2	10.56	1615.68	12.61	1929.33	385	1544.33	10.09	317	1612.33	10.54

TOTALS	49.86	7628.58	59.53	9108.09	4403	4705	30.75	3630	5478	36



Portable Fuel Containers Rule:  Phase I 

 

This measure introduces performance standards for portable fuel
containers and spouts. The standards are intended to reduce emissions
from storage, transport and refueling activities. The rule also included
administrative and labeling requirements. Compliant containers must
have: only one opening for both pouring and filling, an automatic
shut-off to prevent overfill, an automatic sealing mechanism when not
dispensing fuel and specified fuel flow rates, permeation rates and
warranties. 

Source Type Affected 

 

Any person or entity selling, supplying or manufacturing portable fuel
containers, except containers with a capacity of less than or equal to
one quart, rapid refueling devices with capacities greater than or equal
to four gallons, safety cans and portable marine fuel tanks operating
with outboard motors, and products resulting in cumulative VOC emissions
below those of a representative container or spout. 

 

Control Strategy 

 

Maryland adopted Phase I of the Ozone Transport Commission (OTC) Model
Rule for Portable Fuel Containers in January 2002.  The rule applies to
all counties in the nonattainment area.  Reductions from this rule
increase annually beginning with implementation in the State of Maryland
on January 1, 2004.

 

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.26

VOC Emission Reductions for 2009 (TPD):	0.32 

 

Emission Benefit Calculations 

 

Projected reductions are based on an emission reduction factor of 75%
after full implementation after 10 years.  Implementation began in 2004.
 In 2008, the emission reduction factor is 41.3%.  In 2009, the emission
reduction factor is 48.8%. 

 

References 

 

E.H. Pechan, “Control Measure Development Support Analysis for the
Ozone Transport Commission Model Rules”, March 31, 2001. 

Architectural and Industrial Maintenance Coatings Rule 

 

This rule requires manufacturers to reformulate various types of
coatings to meet VOC content limits. Affected products include
architectural coatings, traffic markings, high-performance maintenance
coatings and other special-purpose coatings. It uses more stringent VOC
content limits than the existing Federal consumer products rule. 

 

Source Type Affected 

 

The measure affects all manufacturers of affected coatings. 

 

Control Strategy 

  

Maryland adopted this rule on March 29, 2004.  The rule will apply to
all counties in the nonattainment area.   Compliance with this rule was
required as of January 1, 2004. 

 

The VOC content limits in this rule are based on a Suggested Control
Measure (SCM) adopted by the California Air Resources Board (CARB) and a
State and Territorial Air Pollution Program Administrators/Association
of Local Air Pollution Officials (STAPPA/ALAPCO) model rule or OTC
coatings. Manufacturers are expected to comply with this rule using
primarily EPA Test Method 24. 

 

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.39

VOC Emission Reductions for 2009 (TPD):	0.39  

 

Emission Benefit Calculations 

 

Projected reductions are based on an emission reduction factor of 31%,
based on Pechan (2001).   

 

References 

 

E.H. Pechan, “Control Measure Development Support Analysis for the
Ozone Transport Commission Model Rules”, March 31, 2001. 

Consumer Products Rule:  Phase I 

 

Phase I of the Consumer Products Rule required reformulation of
approximately 80 types of consumer products to reduce their VOC content.
It uses more stringent VOC content limits than the existing Federal
consumer products rule. The rule also contains requirements for labeling
and reporting. 

 

Source Type Affected 

 

Manufacturers of various specialty chemicals named in the rule, such as
aerosol adhesives, floor wax strippers, dry cleaning fluids and general
purpose cleaners. 

 

Control Strategy 

 

Phase I of the Ozone Transport Commission (OTC) Model Rule for
Reformulated Consumer Products became effective in the State of Maryland
on August 18, 2003.  

  

Manufacturers are expected to demonstrate compliance with the rule
primarily through a California Air Resources Board (CARB) test method.
If complying with the VOC contents becomes difficult, flexibility
options are provided. 

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.14

VOC Emission Reductions for 2009 (TPD):	0.14  

  

Emission Benefit Calculations 

 

Projected reductions are based on an emission reduction factor of 14.2
percent, based on Pechan (2001).   

References 

 

E.H. Pechan, “Control Measure Development Support Analysis for the
Ozone Transport Commission Model Rules”, March 31, 2001. 

Industrial Adhesives and Sealants Rule 

 

This rule establishes VOC content limitations for industrial and
commercial application of solvent-based adhesives and sealants. Controls
will cover adhesives, sealants, adhesive primers, sealer primers,
adhesive application to substrates, and aerosol adhesives.  VOC content
limits are similar to those contained in the CARB Reasonably Available
Control Technology (RACT) or Best Available Control Technology (BACT)
document for adhesives and sealants (Dec. 1998).   

 

Source Type Affected 

 

Manufacturers and distributors of industrial adhesives and sealants. 

 

Control Strategy 

  

The State of Maryland will adopt the Ozone Transport Commission (OTC)
Model Rule for Industrial Adhesives and Sealants by May 1, 2008. 

 

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.00

VOC Emission Reductions for 2009 (TPD):	0.10  

 

Emission Benefit Calculations 

 

Emission reductions are based on a 64 percent reduction in emissions of
VOC from the baseline. Further details are available in OTC Technical
Support Document (2006). 

 

References 

 

OTC 2006.  Identification and Evaluation of Candidate Control Measures: 
Draft Technical Support Document.  Prepared by MACTEC Federal Programs,
Inc., Herndon, Virginia for the Ozone Transport Commission. August 4,
2006]

Portable Fuel Containers Rule:  Phase II 

 

This measure expands existing performance standards for portable
gasoline containers and spouts to kerosene containers. The standards are
intended to reduce emissions from storage, transport and refueling
activities. The rule also included administrative and labeling
requirements. Compliant containers must have: only one opening for both
pouring and filling, an automatic shut-off to prevent overfill, an
automatic sealing mechanism when not dispensing fuel and specified fuel
flow rates, permeation rates and warranties. 

 

Source Type Affected 

 

Any person or entity selling, supplying or manufacturing portable fuel
containers, except containers with a capacity of less than or equal to
one quart, rapid refueling devices with capacities greater than or equal
to four gallons, safety cans and portable marine fuel tanks operating
with outboard motors, and products resulting in cumulative VOC emissions
below those of a representative container or spout. 

 

Control Strategy 

  

The State of Maryland will adopt the Ozone Transport Commission (OTC)
Model Rule for the second phase of the portable fuel container rule by
May 1, 2008.

 

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.00

VOC Emission Reductions for 2009 (TPD):	0.03  

Emission Benefit Calculations 

 

Projected reductions are based on an emission reduction factor of 58%
after full implementation after 10 years.  Implementation will begin in
2009.  In 2008, the emission reduction factor is 0.00%.  In 2009, the
emission reduction factor is 5.8%.  Further details are available in OTC
Technical Support Document (2006). 

References 

 

OTC 2006.  Identification and Evaluation of Candidate Control Measures: 
Draft Technical Support Document.  Prepared by MACTEC Federal Programs,
Inc., Herndon, Virginia for the Ozone Transport Commission. August 4,
2006

Consumer Products Rule:  Phase II 

 

Phase II of the Consumer Products Rule involves adopting the CARB
7/20/05 Amendments which sets new or revises existing limits on 13
consumer product categories.  It uses more stringent VOC content limits
than the existing federal consumer products rule. The rule also contains
requirements for labeling and reporting. 

 

Source Type Affected 

 

Manufacturers of various specialty chemicals named in the rule, such as
aerosol adhesives, floor wax strippers, dry cleaning fluids and general
purpose cleaners. 

  

Control Strategy 

  

The State of Maryland will adopt the Ozone Transport Commission (OTC)
Model Rule for the second phase of the consumer products rule by May 1,
2008.

 

Projected Reductions

VOC Emission Reductions for 2008 (TPD):	0.00

VOC Emission Reductions for 2009 (TPD):	0.02  

Emission Benefit Calculations 

 

Emission reductions are based on an additional 2 percent reduction in
emissions of VOC from the baseline. Further details are available in OTC
Technical Support Document (2006). 

 

References 

 

OTC 2006.  Identification and Evaluation of Candidate Control Measures: 
Draft Technical Support Document.  Prepared by MACTEC Federal Programs,
Inc., Herndon, Virginia for the Ozone Transport Commission. August 4,
2006

Rule Phase In

The following rules have a phase in period for the Baltimore
Nonattainment Area and give the region phased in emissions benefits:  

Area Sources:

Additional phase in of reductions from Federal Locomotives Rule 

Federal Rule related to On-Board Refueling/vapor recovery for LD Trucks
(2004) 

Nonroad Sources:

Federal 2004 Nonroad Heavy Duty Diesel Rule (negligible benefits by
2009) 

6.3  Voluntary and Innovative Measures

 

EPA’s voluntary measures policy, “Guidance on Incorporating
Voluntary Mobile Source Emission Reduction Programs in State
Implementation Plans”, establishes criteria under which emission
reductions from voluntary programs are creditable in a SIP.  This policy
permits states to develop and implement innovative programs that partner
with local jurisdictions, businesses and private citizens to implement
emission-reducing behaviors at the local level.  

Inclusion of the following programs in the control measures portion of
this attainment plan is not intended to create an enforceable commitment
by MDE or the State to implement the programs or to achieve any specific
emission reductions projected as a result of implementation of the
programs, and neither MDE, nor the State makes any such commitment.  In
addition, MDE does not rely on any emission reductions projected as a
result of implementation of these programs to demonstrate attainment. 
While the emission reductions from these programs could be substantial
and could lead to significant regional air quality benefits, actual air
quality benefits are uncertain.  Consequently, projected emission
reductions from these programs are not included in the emission
inventory, the attainment modeling, the reasonable further progress
calculation or any other area of the SIP where specific projected
emission reductions are identified.  

Regional Forest Canopy Program:  Conservation, Restoration, and
Expansion

 

Expanded tree canopy cover is an innovative voluntary measure proposed
to improve the air quality in Cecil County, Maryland.  Trees reduce
ground-level ozone concentrations by:

reducing air temperatures and reducing energy used for cooling, and

 

directly removing ozone and NOx from the air. 

Modeling has clearly shown that trees reduce ozone levels. In addition,
trees in an urban setting have far-reaching water quality (e.g.
decreasing storm water runoff), habit and societal benefits. To achieve
a reduction in ground-level ozone under a tree canopy program, it will
be necessary to preserve the current canopy and plant and maintain a
significant number of new trees. 

The current regional tree canopy is composed of mixed native hardwoods
and urban plantings.  On average these species require 30 years to
mature so the short term benefits of a tree program are not substantial
yet still significant.  To achieve area wide canopy expansion will
require long-term commitment by the state and local agencies, volunteer
organizations, and private landowners.

Achieving maximum benefits from this type of program will require the
following types of commitments:

1) Initiate and/or enhance efforts to support, monitor, evaluate, and
report preservation of existing urban tree canopy and canopy expansion
efforts.  

2) Implement urban forestry programs to affect air and surface
temperature, wind speed, and reduce VOC emissions. Programs include
sustained tree planting, reduced mowing and lawn maintenance and tree
planting initiatives for streets, parking lots, and government-owned
facilities.

3) Providing assistance and outreach to the landowners and businesses to
encourage tree conservation, planting and maintenance.

4) Initiate development of a comprehensive plan that will establish a
detailed regional baseline and outline strategies to preserve, enhance,
increase, and protect measure and track overall forest canopy change in
the region over the next 20 years.

5) Monitor these activities and report annually.  

Current Programs 

While Maryland has over 40 state programs that support, encourage, or
require the planting of trees, five of these tools are of special
importance for implementation at the local level:

Forest Conservation Act

Critical Areas Act

Mitigation Requirements

Comprehensive Plans Requirements

Urban and Community Forestry Programs

Special attention will be paid to how these programs can be coordinated
with new local ordinances and initiatives to enhance their use in tree
protection, canopy preservation, and expansion to achieve regional air
quality (SIP) goals.  

Control Strategy

Coordination

This type of measure will require collaboration among the various state
and local agencies that support, encourage, and require tree planting.
Currently, numerous agencies bear responsibility for implementing and
tracking tree planting related activities, but there is no centralized
repository for this information.  The state can be encouraged to commit
to create a new program to coordinate tree-planting programs. This
program would be housed within the Department of Natural Resources
Maryland Forest Service and would be charged with management of a tree
planting database and promoting outreach efforts to landowners and
stakeholder groups. This database would be used to compile baseline data
(including maps and descriptive information about each nonattainment
county in the planning area), information about tree plantings (new and
replacement trees) and canopy change. 

Canopy Preservation

The state coordinating office will work with local governments to fully
implement key programs. Particular attention will be given to those who
set conservation, tree planting and canopy goals and reforestation
standards for local authorities to track during the development process.
Local authorities will be encouraged to:

track efforts aimed at preserving existing canopy, 

provide the Resource agency with data regarding preservation efforts
including new ordinances and development tools, 

. 

The effectiveness of canopy preservation efforts could then be
periodically evaluated.

Public Outreach

The region would need to commit to undertake a public outreach program
designed to promote tree planting. This need could build upon the
Chesapeake Bay Agreement Forestry Directive and local land use
guidelines. Past initiatives under Maryland programs have included
financial incentives to private landowners for planting trees.   MDE
could potentially approach Baltimore Metropolitan Council, state
government agencies, and local governments to work with volunteer tree
planting organizations, landowners, and stakeholder groups to support
tree planting and conduct educational outreach regarding documenting and
reporting voluntary planting and maintenance programs. 

Canopy Goals

. 

Strategic Tree Planting

Biogenic volatile organic compounds (BVOCs), an ozone precursor, are
emitted by some tree species as a natural process.  Expanding the canopy
primarily with trees whose BVOC emissions are lower will have a
significant impact on overall emissions, a key issue in reducing BVOCs.
A right tree –right place strategy will need to be encouraged to
garner the maximum benefits from this type of program.

Clean Air Teleworking Initiative

The state of Maryland, on occasion, experiences unhealthful levels of
the air pollutants ground level ozone and fine particles.  When air
quality elevates to unhealthful levels it poses significant health and
economic impacts to the citizens of the state of Maryland.  To address
air pollution concerns and requirements, the State of Maryland has
implemented over 100 pollution control programs affecting industries,
small businesses, mobile sources, and the general public since 1990,
when the modern-day Clean Air Act was passed. These programs have
prevented nearly 800 tons of ozone-forming pollutants from entering the
air each day.  In order to inform the public about daily air pollution
levels the Maryland Department of the Environment has been accurately
forecasting and reporting air quality information since 1993.

Traffic congestion is a major problem in Maryland’s metropolitan areas
where  individuals waste hundreds of hours every year stuck in traffic
due to congested roadways.  Numerous studies have demonstrated that
telework programs are advantageous in addressing major environmental,
transportation, productivity, quality of life, and employment issues.

Reduced commuter road miles decrease air polluting vehicle emissions,
gasoline consumption, traffic congestion, and highway maintenance costs
for the citizens of Maryland.  It has been proven that telework provides
economic and organizational benefits to employers, resulting in
increased employee productivity, enhanced employee morale, improved
recruitment and retention of employees, reduced office space and parking
needs, reduced stress, increased job satisfaction, decreased absenteeism
costs, an expanded labor pool, and increased flexibility to meet the
needs of citizens.  The state of Maryland, as a major employer, has
recognized its leadership role to develop substantive programs, such as
teleworking, to reduce commuter road miles traveled by state employees
and enhance productivity

Objective  

The objectives of this campaign are to 1) increase the number of
employees who telework in the Baltimore/Washington metropolitan area and
2) increase the frequency of employees who telework by linking
teleworking and air quality; specifically, encouraging employees to
telework on days when air quality is at its worst.  

The decision to encourage teleworking on bad air days will be guided by
the Air Quality Index (AQI), a nationwide, color-coded scale used by the
U.S. Environmental Protection Agency to communicate air quality to the
public.  “Code Orange” is considered unhealthy for sensitive groups
(children, the elderly, and those with heart or lung conditions) and
“Code Red” is considered unhealthy for everyone.  “Code Purple,”


 which occurs very infrequently in the region, is considered very
unhealthy for everyone.  Clean Air Partners, a nonprofit organization
that encourages voluntary action to improve air quality, provides a
three-day air quality forecast to local employers through its Air
Quality Action Day (AQAD) program.  A copy of Clean Air Partners’ Air
Quality Action Guide, which incorporated the AQI, is shown in Figure
6.1. Teleworking is encouraged at Code Orange and above.

                  

        Figure 6.1 Air Quality Action Guide

Approach 

Encouraging employees to telework on poor air quality days may result in
numerous employees and managers working at home for several consecutive
days.  This will require advanced preparation by employees, managers,
and coworkers (in the office) to ensure transparency and a consistent
level of productivity.  While this may initially seem challenging from a
management perspective, the added benefit is that employees and managers
will become adept at teleworking concurrently, thereby increasing the
organization’s business continuity capabilities in the event of an
actual emergency.  

Implementation

The following steps are recommended to help businesses successfully
launch their “Clean Air Teleworking” initiative in 2007:

Get Input from Managers – businesses should get input from several
managers to identify potential barriers and solutions to the “Clean
Air Teleworking” initiative.  This could be accomplished by conducting
one-on-one interviews with 4-5 managers or a small discussion group. The
input from the managers could then be used to shape how the program is
developed and implemented, starting with a small pilot involving a
couple of managers supportive of teleworking and the “Clean Air
Teleworking” initiative.  

Become an AQAD Participant – businesses should become an Air Quality
Action Days participant so it can receive the Clean Air Partners’
three-day air quality forecast, which can then be distributed by email
to employees when a poor air quality day (Code Orange, Code Red, or Code
Purple) is forecasted.  

Conduct Pilot – Select managers and employees who will be
participating in the “Clean Air Teleworking” pilot and launch the
program over the summer of 2007.  Conduct an orientation/training
session for participants prior to implementation and follow-up with
brief phone interviews after a multi-day episode to determine if there
were any problems.  Prepare a summary report at the end of the pilot and
share with management and employees.

Implement Tracking System – Ask participants to track their
participation using a web-based system that tracks auto emission
reductions resulting from teleworking (NOx, VOC, CO, and CO2), such as
TeleTrips (  HYPERLINK "https://www.secure-teletrips.com/" 
https://www.secure-teletrips.com/ ).  This information can be reported
at the individual, department/team, and organizational level and
provides continuous feedback on how the program and participants are
improving air quality.  Furthermore, businesses should consider
recognizing individuals or teams/departments with the highest level of
participation and emissions reductions. 

Communicate – businesses should send out several email communications
to all their employees prior to the launch of the “Clean Air
Teleworking” pilot, during implementation, and at the conclusion of
the pilot to explain objectives and keep employees informed. 
Furthermore, employees not participating in the pilot should also
receive the air quality forecast for Code Orange, Code Red, and Code
Purple days and be encouraged to take other voluntary measures at work
and at home (e.g., carpooling, eating in the cafeteria rather than going
out for lunch, refueling after dusk, and postponing mowing.)

Expand Program – Share the results of the pilot with all staff and
encourage other managers and employees to participate in the program in
future years.  Repeat orientation/training for new participants prior to
implementation, conduct phone or on-line survey with participants during
implementation, track participation/results for all participants, and
recognize or reward individuals teams/departments with the highest level
of participation and emissions reductions.   

An initial pilot program will be initiated throughout the Maryland
Department of the Environment (MDE) that will encourage telecommuting
opportunities for qualified personnel when air quality is forecasted to
be in the Code Orange (Unhealthy for Sensitive Groups) range or above. 
The MDE pilot program will launch in May 2007.

Expansion of Program

Additional strategies will be employed to encourage a wider
participation in the Clean Air Teleworking Initiative.  Some of these
strategies will include: Promoting participation amongst all Maryland
State agencies.  Working with the Baltimore Metropolitan Council and the
Metropolitan Washington Council of Governments to promote program
throughout local jurisdictions.  Clean Air Partners will serve as the
work group to implement the program. Develop strategic plan for local
governments and federal agencies.  Encourage participation within
private sector. Develop a merit-based recognition/award system for
participation. Promote program throughout the Ozone Transport
Commission.  A timeline of the implementation steps is shown in Table
6.3.

Table 6.4	Clean Air Teleworking Time Line

Task/Step	Apr-07	May-07	Jun-07	Jul-07	Aug-07	Sep-07	Oct-07	Nov-07	Dec-07

1.0	Telework Toolkit	 	 	 	 	 	 	 	 	 

1.1	Research materials	x	 	 	 	 	 	 	 	 

1.2	Compile toolkit	x	 	 	 	 	 	 	 	 

1.3	Integrate with Clean Air Partners web site	 	x	 	 	 	 	 	 	 

 	 	 	 	 	 	 	 	 	 	 

2.0	Clean Air Teleworking Pilot	 	 	 	 	 	 	 	 	 

2.1	Recruit organization(s)	 	x	x	 	 	 	 	 	 

2.2	Develop/implement communications plan	 	x	x	 	 	 	 	 	 

2.3	Conduct interviews/focus groups with managers	 	x	x	 	 	 	 	 
 

2.4	Identify participants (e.g., specific units/departments)	 	x	x	 
 	 	 	 	 

2.5	Conduct orientation 	 	 	x	 	 	 	 	 	 

2.6	Launch and conduct pilot	 	 	x	x	x	x	 	 	 

2.6	Conduct "spot" phone interviews/email surveys 	 	 	x	x	x	x	 	 
 

2.7	Implement tracking system	 	x	x	x	x	x	 	 	 

2.8	Track and report results	 	x	x	x	x	x	x	x	 

2.9	Expand program	 	 	 	 	 	 	 	x	x



The Clean Air Teleworking Initiative will develop the program in close
coordination with other entities who have some role in telework
implementation (Commuter Connections, Maryland Telework Partnership with
Employers, Telework!Va, and the newly created Office of Telework
Promotion and Broadband Assistance in VA.

Supporting Material

Clean Air Partners will compile and customize a telework tool kit that
would be posted on the organization’s web site.  The tool kit would
provide on-line resources to help employers start or expand a telework
program, including the use of “episodic” teleworking on poor air
quality days.

Air Quality Benefits of an Aggressive Telecommute Strategy

To simulate the effects of a very aggressive telecommute program, the
University of Maryland modeled the air quality change that would result
from a 40% reduction of vehicle miles traveled from the road in the
nonattainment areas of Baltimore, Philadelphia, and Washington, D.C. on
38 high ozone days in the summer of 2002.  Changes in emissions were
implemented as a flat 40% reduction in vehicle miles traveled in each
county of the three nonattainment areas.  The effects of implementing
such a program were modeled using version 4.4 of the CMAQ model.  The
model results showed that across the three nonattainment areas tested,
an aggressive telecommute program has the potential for considerable
benefit to air quality, with fairly uniform benefits across all three
areas.  The highest monitors in the Philadelphia and Washington, D.C.
nonattainment areas would see the largest benefits from this program,
suggesting that it is targeting the most troublesome monitors on the
worst ozone days.  Benefits in all three nonattainment areas averaged
over 2 ppbv ozone.  The full report is included in appendix G

High Electricity Demand Day (HEDD) Initiative

Emissions from Electric Generating Units (EGUs) are higher on high
electric demand days, resulting in poorer air quality. High electrical
demand day (HEDD) operation of EGUs generally have not been addressed
under existing air quality control requirements, and these units are
called into service on the very hot days of summer when air pollution
levels typically reach their peaks. 

The Ozone Transport Commission (OTC) has been meeting with state
environmental and utility regulators, EPA staff, EGU owners and
operators and the independent regional systems operators to assess
emissions associated with HEDD during the ozone season and to address
excess NOx emissions on HEDDs. The OTC has found that NOx emissions are
much higher on a high electrical demand day than on a typical summer day
and there is the potential to reduce HEDD emissions by approximately 25
percent in the short term through the application of known control
technologies. HEDD units consists of gasoline and diesel combustion
turbines, coal and residual oil burning units. 

On March 2, 2007, the OTC states and the District of Columbia agreed to
a Memorandum of Understanding (MOU) committing to reductions from the
HEDD source sector. The MOU includes specific targets for a group of six
states to achieve reductions in NOx emissions associated with HEDD units
on high electrical demand days during the ozone season. These states
agreed to achieve these reductions beginning with the 2009 ozone season
or as soon as feasible thereafter, but no later than 2012. The remaining
OTC states including Virginia and the District of Columbia agreed to
continue to review the HEDD program and seek reductions where possible
but they do not have a formal emissions reduction target in the MOU. 
The OTC MOU is included in Appendix D.

Emission Reductions from Transportation Measures

Substantial funding commitments have come from State and local agencies
and private employers for promotion of strategies to reduce mobile
emissions. Examples of these measures include idling reduction,
ridesharing, telecommuting, and transit use as well as vehicle
replacement and retrofit measures, and bicycle and pedestrian programs.
These funding commitments produce reductions in emissions, some of which
are being reflected in transportation plans. 

Although these programs are working to reduce emissions from mobile
sources and play an important role in the transportation sector’s
contribution to cleaner air, neither MDE, nor the State intends their
inclusion in this SIP to constitute enforceable commitments to implement
these programs or to achieve any emission reductions projected as a
result of implementing these programs, and neither MDE, nor the State
makes any such commitment.  These directionally correct programs will
continue to be used outside of the SIP for transportation planning
purposes as needed.

The following are descriptions of selected emission reduction strategies
in Cecil County.

Traffic Flow Improvements (CHART)

The Coordinated Highways Action Response Team program, operated by MDOT
and Maryland State Police, focuses its operations on non-recurring
congestion such as backups caused by accidents. The Statewide Operations
Center, and the three satellite Operations Centers in the region, survey
the state’s roadways to quickly identify incidents through the use of
ITS (Intelligent Transportation System) technology. CHART also includes
traffic patrols, which have been operating during peak periods on many
of the state’s highways since the early 1990s. CHART and MdTA have a
number of ITS devices in Cecil County.  These include CCTV cameras,
variable message signs and 24 response vehicle and emergency traffic
controls along I-95 in Cecil County. Currently MdTA and CHART are
working together to install a CHART workstation that will allow the
opportunity to view all CHART and MdTA cameras in the county. These
continued incident management and emergency information improvements to
motorists will help reduce vehicular delay. In addition to existing MdTA
and CHART devices there are other additional installations proposed that
will help improve or maintain traffic flow along the following Cecil
County roadways: US 40, US 301, MD 213, and I-95.

Truck Stop Electrification (TSE)

Truck Stop Electrification allows truckers to shut down their engine and
obtain electric power and “creature comforts” while resting. TSEs
reduce diesel emissions and reduce noise and wear and tear on the truck
engine. IdleAire truck stops provide electricity (110V AC), cab
heating/cooling, television and movies, telephone and Internet access.
IdleAire has over 100 locations nationally, three in Maryland. The
Maryland sites are located in Baltimore and Jessup, both in the
Baltimore region. An additional TSE has been put in place in Cecil
County at I-95 and MD 279.

Electronic Toll Collection

The Maryland Transportation Authority (MdTA) commenced operation of its
electronic toll collection system, MTAG, at the authority’s three
Baltimore harbor crossing facilities in 1999. The I-95 Tydings Memorial
Bridge and US 40 Thomas J. Hatem Memorial Bridge crossings of the
Susquehanna River are also now equipped with electronic toll facilities.
An Automatic Vehicle Identification (AVI) toll decal, a form of
electronic toll collection, also is offered at the Hatem Bridge. This $5
AVI decal allows unlimited trips across the bridge during a one-year
period. Decals can be used only on two-axle vehicles and cannot be used
by vehicles being towed or towing other vehicles. As of January 2004, 45
percent of vehicles using MdTA facilities used electronic toll tags.
MdTA is a member of the E-Z Pass InterAgency Group, a coalition of
Northeast Toll Authorities. MdTA established reciprocity with the E-Z
Pass system in 2001, enabling travelers in Maryland, as well as at most
toll facilities in New York, New Jersey, Delaware, Pennsylvania,
Massachusetts, Virginia, and West Virginia to pay tolls using one
electronic device.

Maryland Commuter Tax Credit

As of January 2000, a tax credit went into effect statewide that allows
employers to claim a 50% state tax credit for providing transit benefits
(subsidy) to an employee of up to $52.50 per month, which an employer
may provide to an employee without tax consequences under the Federal
tax law. It is expected that the state tax credit will be even more
attractive to employers as a benefit to offer employees than the Federal
law (a direct tax credit as opposed to an allowable business expense).
This feature of the Maryland law also has the potential to encourage
increased transit use by low and moderate-income employees. Under
provisions of both the 1999 and 2000 Maryland laws, private non-profit
organizations will also be able to participate in the program. Employers
will be able to claim tax credits for providing transit passes and
vouchers, guaranteed ride home, and parking cash-out programs. Similar
to the IRS benefits, the Maryland Commuter Tax Benefit program does not
provide financial assistance to carpoolers. Information is also provided
online and employers are able to register to participate in the program
over the internet.

Bicycle/pedestrian Enhancements

Through MDOT, the Maryland State Highway Administration (SHA) has worked
to engineer and implement new and improved bicycle and pedestrian
facilities, and has implemented programs to encourage pedestrians. SHA
has a stated goal of providing 200 miles of marked bicycle lanes
throughout Maryland by December 31, 2006. In addition, SHA has developed
the Maryland SHA Bicycle and Pedestrian Guidelines to provide general
guidance on design. The state has a policy of considering sidewalks to
reinforce pedestrian safety and promote pedestrian access adjacent
to roadway projects being constructed or reconstructed. Special
efforts are made to facilitate pedestrian travel near schools. In
addition, bicycle safety and travel are being accommodated by
construction of wider shoulders and/or curb lanes to separate motor
vehicles from the cyclists. In regard to bicycle or pedestrian
travel in controlled access roadway corridors there is almost
always a separation between the bike or pedestrian travel and the
motor vehicles. Only along roadways where speeds or mix of the travel
modes could result in serious accidents are sidewalks and
bicycle travel not promoted.

 

Refurbishing MARC and other rail vehicles

In order to insure the reliability, safety and comfort of MARC equipment
the rolling stock is periodically overhauled. These include 26 MARC cars
that have been or are scheduled to be refurbished between FY2005 and FY
2008.  In addition, 23 locomotives are in the process of being
overhauled and retrofitted to cleaner Federally required TIER standards
in force at the time of the improvement. This is an ongoing effort that
started in FY 2005. All the locomotives will not be improved until 2012.
100 Metro rail cars have recently been overhauled to extend their life
and make them more comfortable and reliable for passengers and
commuters. The MARC Penn Line includes service to the Perryville station
in western Cecil County.

 

Park and Ride Lots

The SHA and MdTA have three park and ride lots in Cecil County adjacent
to I-95.  These lots serve to accommodate carpool based work
trips into the Baltimore and Wilmington regions.  The benefits of the
reduction in VMT and VT provides for a reduction in regional congestion
and vehicular emissions.



7.0  Reasonably Available Control Measure (RACM) Analysis

Section 172(c)(1) of the Clean Air Act requires State Implementation
Plans (SIPs) to include an analysis of Reasonably Available Control
Measures (RACM). This analysis is designed to ensure that the Cecil
County is implementing all reasonably available control measures in
order to demonstrate attainment with the 8-hour ozone standard on the
earliest date possible. This chapter presents a summary of analysis
conducted to determine whether the SIP includes all reasonably available
control measures. Full details of the analysis are included in Appendix
E.  

The Maryland Department of the Environment (MDE) has prepared this RACM
analysis using two independently developed lists of potential control
measures.  The first list consists of the RACM analysis performed for
the Washington DC Region’s 8-hour Ozone SIP.  The MDE worked very
closely with all the DC region’s jurisdictions in the development of
the DC Region’s RACM analysis.  Understanding that the adjacent
Washington, DC non-attainment region is both extremely similar to the
metropolitan Philadelphia region and was also undertaking their RACM
analysis, MDE incorporated the Washington RACM criteria and analysis
into the 8-hour ozone SIP for Cecil County.

The Washington RACM analysis included a series of regional calls over
several months to review over 200 suggested measures from numerous
sources to create a master listing of measures.  Each of over 200
measures was individually evaluated against established RACM criteria
(the criteria is explained below). 

In addition to a careful review of the Washington DC Region’s RACM
analysis the MDE also worked closely with the Baltimore Metropolitan
Council (BMC) in developing a small list of potential transportation
emission reduction measures during the fall of 2006.  This analysis
yielded a list of 24 specific measures that could be implemented in the
Baltimore Nonattainment area for emission reduction purposes.  Based on
the criteria used for RACM none of these 24 measures are to be
considered RACM but these measures shall be kept on a short list of
measures if the region needs additional reductions.

 

At the completion of the RACM analysis it was determined that no
measures met the criteria. 

 

7.1 Analysis Overview and Criteria 

 

The RACM requirement is rooted in Section 172(c)(1) of the Clean Air
Act, which directs states to “provide for implementation of all
reasonably available control measures as expeditiously as
practicable”. In its 1992 General Preamble for implementation of the
1990 Clean Air Act Amendments (57 FR 13498), EPA explains that it
interprets Section 172(c)(1) as a requirement that states incorporate in
a SIP all reasonably available control measures that would advance a
region’s attainment date. However, regions are obligated to adopt only
those measures that are reasonably available for implementation in light
of local circumstances. In the Preamble, EPA laid out guidelines to help
states determine which measures should be considered reasonably
available: 

 

If it can be shown that one or more measures are unreasonable because
emissions from the sources affected are insignificant (i.e. de minimis),
those measures may be excluded from further consideration…the
resulting available control measures should then be evaluated for
reasonableness, considering their technological feasibility and the cost
of control in the area to which the SIP applies…In the case of public
sector sources and control measures, this evaluation should consider the
impact of the reasonableness of the measures on the municipal or other
government entity that must bear the responsibility for their
implementation.  

 

In its opinion on Sierra Club v. EPA, decided July 2, 2002, the U.S.
Court of Appeals for the DC Circuit upheld EPA’s definition of RACM,
including the consideration of economic and technological feasibility,
ability to cause substantial widespread and long-term adverse impacts,
collective ability of the measures to advance a region’s attainment
date, and whether an intensive or costly effort will be required to
implement the measures. Consistent with EPA guidance and the U.S.
District Court’s opinion, the Cecil County/Wilmapco region has
developed specific criteria for evaluation of potential RACM measures.
Individual measures must meet the following criteria: 

Will reduce emissions by the beginning of the 2008 ozone season (May 1,
2008) 

Enforceable  

Technically feasible 

Economically feasible (proposed as a cost of $3,500-$5,000 per ton or
less) 

Would not create substantial or widespread adverse impacts within the
region 

Emissions from the source being controlled exceed a de minimis
threshold, proposed as 0.1 tons per day 

An explanation of these criteria is given in succeeding sections.  

Implementation Date 

 

EPA has traditionally instructed regions to evaluate RACM measures on
their ability to advance the region’s attainment date. This means that
implementation of a measure or a group of measures must enable the
region to reduce ozone levels to the 84 ppb required to attain the
eight-hour ozone standard at least one year earlier than expected. As
the Cecil County, Maryland/Wilmapco region currently expects to reduce
ozone levels to 84 ppb during the 2009 ozone season, any RACM measures
must enable the region to meet the 84 ppb standard by May 1, 2008, the
beginning of the 2008 ozone season. 

Enforceability 

 

When a control measure is added to a SIP, the measure becomes legally
binding, as are any specific performance targets associated with the
measure. If the state or local government does not have the authority
necessary to implement or enforce a measure, the measure is not
creditable in the SIP and therefore cannot be declared a RACM. A measure
is considered enforceable when all state or local government agencies
responsible for funding, implementation and enforcement of the measure
have committed in writing to its implementation and enforcement. 

 

In addition to theoretical enforceability, a measure must also be
practically enforceable. If a measure cannot practically be enforced
because the sources are unidentifiable or cannot be located, or because
it is otherwise impossible to ensure that the sources will implement the
control measure, the measure cannot be declared a RACM. One exception is
voluntary measures, such as those implemented under EPA’s Voluntary
Measures Guidance. 

 

Technological Feasibility 

 

All technology-based control measures must include technologies that
have been verified by EPA. The region cannot take SIP credit for
technologies that do not produce EPA-verified reductions. 

Economic Feasibility and Cost Effectiveness 

 

EPA guidance states that regions should consider both economic
feasibility and cost of control when evaluating potential RACM measures.
Therefore, the Cecil County/Wilmapco region has specified a
cost-effectiveness threshold for all possible RACM measures. Measures
for which the cost of compliance exceeds this threshold will not be
considered RACM. 

 

In setting this threshold, the region took into consideration two major
factors. First, EPA has issued guidance regarding the relationship
between RACT and RACM. In its RACM analysis for the Dallas/Forth Worth
nonattainment area, EPA states: 

“RACT is defined by EPA as the lowest emission rate achievable
considering economic and technical feasibility. RACT level control is
generally considered RACM for major sources.” 

 

In Cecil County, installation of Reasonably Available Control Technology
(RACT) costs is as low as approximately $3,500 per ton.  The region
proposes a threshold of $3,500-$5,000 for cost effectiveness.  

 

Substantial and Widespread Adverse Impacts 

 

Some candidate RACM measures have the potential to cause substantial and
widespread adverse impacts to a particular social group or sector of the
economy. Due to environmental justice concerns, measures that cause
substantial or widespread adverse impacts will not be considered RACM. 

 

De Minimis Threshold 

 

In the General Preamble, EPA allows regions to exclude from the RACM
analysis measures that control emissions from insignificant sources and
measures that would impose an undue administrative burden. Under
moderate area RACT requirements, the smallest major source subject to
RACT emits 50 tpy (however, MDE considered 25 tpy sources), or
approximately 0.1 tpd.  Following these requirements and the precedent
set by the San Francisco RACM analysis, the region will not consider
control measures affecting source categories that produce less that 0.1
tpd NOx or VOC emissions. 

 

 

Advancing Achievement of 84 ppb Standard 

 

In order for measures to be collectively declared RACM, implementation
of the measures must enable the region to demonstrate attainment of the
85 ppb ozone standard one full ozone season earlier than currently
expected. As discussed in this SIP document and the relevant appendices
Cecil County currently expects to demonstrate attainment in 2009. 
Therefore, any RACM measures would need to enable the region to meet the
84 ppb standard during the 2008 ozone season. 

 

Intensive and Costly Effort 

 

When considered together, the implementation requirements of any RACM
measures cannot be so great as to preclude effective implementation and
administration given the budget and staff resources available to Cecil
County. 

 

7.2 RACM Measure Analysis 

 

Analysis Methodology 

 

The sources of strategies analyzed for the Cecil County include the
following: 

Clean Air Act Section 108(f) measures (Transportation Control Measures) 

Transportation Emissions Reduction Measures (TERMs) listed in recent
Transportation Improvement Programs (TIPs) for the Metropolitan
Baltimore and Washington DC regions

Measures identified through a review of emission reduction strategies
report prepared for the Baltimore Metropolitan Council

Measures considered in Washington, Atlanta and Houston RACM analyses 

                

Analysis Results 

 

Appendix E provides lists (in tabular form) organized by source sector,
of potential measures evaluated against the RACM criteria.  Each
specific RACM criteria was reviewed for each individual measure
identified on the lists.

 

Based on this analysis none of the measures reviewed were identified as
RACM for Cecil County.

 

7.3 RACM Determination 

Though the measures listed in Appendix E did not meet the criteria for
RACM, many of the measures are worthwhile measures that reduce
emissions. These measures will be considered potential control measures
for future SIPs prepared for Cecil County. 

References 

 

US EPA, “State Implementation Plans; General Preamble for the
Implementation of Title I of the Clean Air Act Amendments of 1990”,
(57 FR 13498), April 16, 1992. 

 

US EPA Region VI, “Reasonably Available Control Measures (RACM)
Analysis for the Dallas/Fort Worth Ozone Nonattainment Area”, December
2000. 

 

Bay Area Air Quality Management District, Metropolitan Transportation
Commission and Association of Bay Area Governments, “Bay Area 2001
Ozone Attainment Plan,” October 24, 2001, Appendix C. 

 

 E.H. Pechan & Associates, Inc., “ Review of Emission Reductions
Strategies”,

          December 8, 2006.

8.0 Mobile Source Conformity   

Transportation conformity ("conformity") is a provision of the Clean Air
Act that ensures that Federal funding and approval goes to those
transportation activities that are consistent with air quality goals.
Conformity applies to transportation plans and projects funded or
approved by the Federal Highway Administration (FHWA) or the Federal
Transit Administration (FTA) in areas that do not meet or previously
have not met air quality standards for ozone, carbon monoxide,
particulate matter, or nitrogen dioxide.

In order to balance growing metropolitan regions and expanding
transportation systems with improving air quality, EPA established
regulations ensuring that enhancements to existing transportation
networks will not impair progress towards air quality goals.  Under the
Clean Air Act Conformity Regulations, transportation modifications in a
nonattainment area must not impair progress made in air quality
improvements.  These regulations, published in EPA's Transportation
Conformity rule on November 24, 1993 in the Federal Register and amended
in a final rule signed on July 31, 1997, require that transportation
modifications "conform" to air quality planning goals established in air
quality SIP documents.  The 1997 amendments were followed by further
amendments in 2002 and 2004. 

In essence, this SIP submission includes mobile emissions budgets for
NOx and VOC.  These budgets, once found adequate by EPA, shall be used
in all conformity documents for Cecil County.  In order for a
transportation plan to “conform” the estimated emissions from the
transportation plan can’t exceed the emissions budgets set via this
SIP submission.  If the estimated emissions are shown to exceed the
budget then mitigation measures must be taken to ensure emissions will
not exceed the emission budgets.  

Responsibility for Making a Conformity Determination

The policy board of a Metropolitan Planning Organization (MPO), in
consultation with the Maryland Department of Transportation (MDOT) and
MDE, is responsible to formally make a conformity determination on its
transportation plans and transportation improvement programs (TIPs)
prior to submittal to the FHWA and FTA for review. The USEPA also may
review and comment on proposed conformity determinations.

If a particular transportation plan’s projected emissions exceed the
mobile emissions budget, the MPO has a variety of mitigation options to
reduce emissions. These may include, but are not limited to, specific
transportation emission reduction measures such as HOV lanes, transit
enhancements, bicycle lanes, diesel retrofits, and idling reductions.

The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A
Legacy for Users (SAFETEA-LU) was enacted on August 10, 2005.  Under
this act, amendments were made to the transportation conformity rules
(Section 6011 of the Act), which required states that have nonattainment
areas like Maryland to revise their existing transportation conformity
SIPs.  Maryland submitted a revised transportation conformity SIP to
USEPA in February of 2007.   Because of changes mandated by SAFETEA-LU,
conformity determinations have to be done at least every four years
instead of the previous three years. 

When a positive conformity determination is not made according to the
required frequency, or in the event that emission mitigation can’t be
agreed upon, a nonattainment area is in conformity “lapse”. This
means that Federal transportation funds allocated to the state, which
contains the lapsed nonattainment area, can only be used for the
following kinds of projects: 

TCMs in Approved SIPs;

Non-Regionally Significant Non-federal Projects;

Regionally Significant Non-federal Projects - only if the project was
approved by all necessary non-federal entities before the lapse. (See
Approval of a Regionally Significant Non-Federal Project by a
Non-Federal Entity later in this Chapter.)

Project phases (i.e., design, right-of-way acquisition, or construction)
that received funding commitments or an equivalent approval or
authorization prior to the conformity lapse.

Exempt Projects - identified under 40 CFR §93.126and 40 CFR §93.127;
and,

Traffic Synchronization Projects - however, these projects must be
included in subsequent regional conformity analysis of MPO's
transportation plan/TIP under 40 CFR §93.128.

The amount of federal funding a state receives is not reduced but such
funds are restricted until the area can again demonstrate conformity.

8.1 Mobile Emissions Budget and the Wilmington Region Transportation
Conformity Process (includes Cecil County)

 

Mobile source emissions for Cecil County’s portion of the long-range
transportation plan known as the Regional Transportation Plan (RTP 2025-
DRAFT RTP 2030), and the three-year Transportation Improvement Program
(TIP) cannot exceed the mobile emissions budget set in this SIP.  The
RTP and the TIP are developed by the Wilmington Area Planning Council
for Cecil County, Maryland and New Castle County, Delaware. The
transportation plans are required to conform to the mobile budget
established in the SIP for the short-term TIP years, as well as for the
forecast period of the long-range plan, which must be at least twenty
years.  Separate and individual mobile emissions budgets are created for
Maryland and Delaware. 

In Cecil County, modifications to the existing transportation network
are advanced through the Wilmington Area Planning Council (WILMAPCO) by
state and local transportation agencies through periodic updates to the
Regional Transportation Plan (RTP) and TIP.  The TIP is updated annually
for the region and includes transportation modifications and
improvements on a three-year program cycle. The latest draft TIP is for
fiscal years 2008-2011. Pursuant to the conformity regulations, the RTP
and TIP must contain analyses of the motor vehicle emissions estimates
for the region resulting from the transportation improvements.  These
analyses must show that the transportation improvements in the TIP and
the plan do not result in a deterioration of (conform to) the air
quality goals established in the SIP.   

8.2 Budget Level for On-Road Mobile Source Emissions  

As part of the development of this SIP, the MDE formally establishes an
8-hour ozone mobile source emissions budget.  This budget will be the
benchmark used to determine if the region's long-range transportation
plan (RTP) and three-year transportation improvements program (TIP)
conform to the SIP.  Under EPA regulations the projected mobile source
emissions for 2008 (for purposes of meeting the CAA requirements related
to reasonable further progress) and 2009 (the region’s attainment
ozone season) become the mobile emissions budgets for the region unless
MDE takes actions to set other budget levels.

Modeling and Data

The 2008 and 2009 mobile emissions inventories are calculated using the
following models and tools: EPA’s MOBILE6.2, the Highway Performance
Monitoring System  (HPMS) model, and the Upper Eastern Short
Transportation Model. A detailed explanation of the models and the
emission estimating methodology can be found in Appendix F.

  

The mobile emissions budget for 2008 Reasonable Further Progress and
2009 attainment are based on the projected 2008 and 2009 mobile source
emissions accounting for all the mobile control measures and projected
regional growth. 

Reasonable Further Progress Mobile Budgets

The mobile emissions budgets for the 2008 Reasonable Further Progress
are based on the projected 2008 mobile source emissions accounting for
all mobile control measures. The mobile emissions budgets for the 2008
Reasonable Further Progress, based upon the projected 2008 mobile source
emissions accounting for all the mobile control measures, are:

2008 RFP Mobile Budgets for the Cecil County Nonattainment Area

VOC (TPD)	2.3

NOx (TPD)	7.9



Attainment Year Mobile Budgets

The mobile emissions budgets for the 2009 attainment year are based on
the projected 2009 mobile source emissions accounting for all mobile
control measures. The mobile emissions budgets for the 2009 Attainment
Year, based upon the projected 2009 mobile source emissions accounting
for all the mobile control measures, are:

2009 Attainment Mobile Budgets for the Cecil County Nonattainment Area

VOC (TPD)	2.2

NOx (TPD)	7.3



The 2009 NOx budget is 7.3 tpd.  An adjustment has been made to the
model output to set the 2009 NOx budget.  Based on table 10-4 in Chapter
10 of this document there are 0.03 tpd of available NOx credits not
needed to satisfy the contingency measures part of this plan.  The MDE
is assigning 0.02 tpd of these additional NOx credits to the 2009 NOx
budget to create the 7.3 tpd NOx budget. 

8.3 Trends in Mobile Emissions 

 

The mobile emissions budgets for 2008 and 2009 for Volatile Organic
Compounds (VOCs) and Nitrogen Oxides (NOx) reflect a continuation of a
downward trend in mobile emissions over time. The VOC and NOx emission
levels for mobile sources provided in Section 8.2 are lower than the
most recently approved mobile budgets for Cecil County of 3.0 tons/day
VOC and 11.3 tons/day NOx from the 2003 modified Phase II Attainment
Plan for the Cecil County nonattainment area. The trend in smaller Cecil
County mobile emissions budgets from 2003 to the 2009 attainment year is
shown in the following chart.

 

The steady reductions in mobile emissions are attributable largely to a
series of increasingly stringent federal regulations requiring cleaner
vehicles and fuels, including the federal Tier II regulations for motor
vehicles. Trends toward reduced mobile emissions are occurring despite
the negative effects of a shift toward the use of higher-emitting, less
fuel-efficient light-duty trucks, such as SUVs instead of passenger cars
and a steady increase in population, employment and vehicle miles
traveled (VMT) within the WILMAPCO region.

The trends of increasing population, employment, and VMT are expected to
remain strong well beyond 2009. The regional cooperative forecasting
process (from the latest Regional Transportation Plan- RTP 2025)
predicts that from 2000 to 2025, regional population will grow by 19%,
households will increase by 24%, and employment will grow by 28%.
Regional VMT is predicted to still outpace these increases over the same
time period with a projected growth of 46%. These trends, however, will
not reverse the expected decline in regional mobile emissions resulting
from cleaner fuels and improved vehicle technology. The recent Tier II
passenger vehicle standards and regulations on emissions from heavy-duty
diesel vehicles and fuels are expected to produce further dramatic
reductions in VOC and NOx emissions as vehicles are replaced and
retrofitted over the next 20 years. It is important to keep in mind,
however, that despite cleaner fuels and improved vehicle technology, the
relationship between land use planning, transportation, and air quality
is important for long-term air quality goals.

9.0  Moderate Area Plan Commitments 		

 

Achieving the results shown in this Plan requires a commitment to
implement the regulatory measures upon which the plan is based. 
Maryland (Cecil County) is taking action to implement regional and local
measures to effectively reduce ozone transport throughout the
Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ 
Nonattainment Area.  Tables 9-1 through 9-5 provide information on the
implementation of each measure.

9.1 Schedules of Adopted Control Measures 

  

Table 9-1 

Maryland (Cecil County) Schedule of Adopted Control Measures  

Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ
Nonattainment Area 

 

Control Measure 	 

Regulation Number 	 

Effective Date 

Federally Mandated Measures 	 	 

High Tech Inspections & Maintenance 	11.14.08 	1/2/95 

State II Vapor Recovery Nozzle 	26.11.24 	2/15/93 

Federal Tier I Vehicle Standards and new Car Evaporative Standards 	40
CFR part 86 	Model Year 1994-1996; Evap Stds. 1996 

Tier 2 Motor Vehicle Emission Standards 	65 FR 6698 

 	2/10/2000 

Non-CTG RACT 	See Table 9-3 	- 

Phase II Gasoline Volatility Controls 	03.03.03.05 	10/26/92 

EPA Non-Road Gasoline Engines Rule 	40 CFR parts 90 and 91 	12/3/96 

EPA Non-Road Diesel Engines Rule 	40 CFR Part 9 et al. 	Model Year
2000-2008 depending on engine size 

State NOx RACT Requirements 	26.11.29.08 	5/10/93 

EPA Nonroad Spark Ignition Marine Engine Rule 	40 CFR Parts 89, 90, 91 
1998 Model Year 

EPA Large Spark Ignition Engines Rule 	40 CFR Parts 89, 90, 91, 94,
1048, 1051, 1065, and 1068 	11/8/2002 

Federal Programs 	 	 

Reformulated Surface Coatings 	 

63 FR 48849 64 FR 34997 65 FR 7736 	 

9/11/98 6/30/99 2/16/00 

National Volatile Organic Compound Emission Standards for Consumer
Products 	63 FR 48819 	9/11/98 

National Low Emissions Vehicle Program 	26.11.20.04 	3/22/99 

Emissions Controls for Locomotives 	63 FR 18998  	6/15/98 

Heavy-Duty Diesel Engine Rule 	63 FR 54694 	12/22/97 

State and Local Measures 	 	 

Reformulated Gasoline (on-road) 	Federal - local opt-in 	1/1/95 

Reformulated Gasoline (off-road) 	Federal - local opt-in 	1/1/95 

Surface Cleaning/Degreasing for Machinery/Automobile Repair 	26.11.19.09
	6/5/95 

Landfill Regulations 	26.11.19.20 	3/9/98 

Seasonal Open Burning Restrictions 	26.11.07 	5/22/95 

Stage I Expansion 	26.11.13.04C 	4/26/93 

Expanded Point Source Regulations to 25 tpy 	26.11.19.01B(4) 	5/8/95 

Graphic Arts Controls 	26.11.19.11 & .18 	6/5/95 & 11/7/94 

Auto and Light Duty Truck Coating Operations 	26.11.19.23 	5/22/95 

Control of VOC Emissions from Vehicle Refinishing 	26.11.19.23 	5/22/95 

Portable Fuel Containers Rule:  Phase I 	26.11.13.07 	1/21/02 

Architectural and Industrial Maintenance Coatings Rule 	26.11.33 
3/29/04 

Reformulated Consumer Products Rule:  Phase I 	26.11.32 	8/18/03 

Control of VOC Emissions from Cold and Vapor Degreasing  	26.11.19.09 
6/5/1995 

Maryland Healthy Air Act	26.11.27	Emergency Regulations Adopted 1/18/07
- Permanent Regulations to be adopted by December 2007

Industrial Adhesives and Sealants Rule	 	Prior to May 2008 

Portable Fuel Containers Rule:  Phase II	 	Prior to May 2008 

Reformulated Consumer Products Rule:  Phase II

Prior to May 2008

Regional Control Measures 	 	 

NOx Phase II Controls 	26.11.27 & .28 

26.11.29 & 30 	10/18/99 

 

Table 9-2

Maryland (Cecil County) Non-CTG RACT

Philadelphia - Wilmington - Atlantic City, PA - DE - MD - NJ
Nonattainment Area

  

Overall requirement in COMAR 26.11.19.02G effective 4-26-93 (20: Md. R
726) 

The following case-by-case RACT regulations have been adopted to ensure
consistency. 

 

 

RACT Regulation 	 

Regulation Number 	 

Effective Date 	 

MD Register 

 

Plastic Parts Coating 	 

26.11.19.07E 	 

6-5-95 	 

22:11 Md R 823 

 

Definition of Gasoline to include JP-4 	 

26.11.13.01 	 

8-11-97 	 

24:16 Md R. 1161 

 

Printing on Plastic 	 

26.11.19.07F 	 

9-8-97 	 

24:18 Md R 1298 

 

Aerospace Coating Operations 	 

26.11.19.13-1 	 

9-22-97 	 

24:19 Md R 1344 

 

Yeast Manufacturing 	 

26.11.19.17 	 

11-7-94 	 

21:22 Md R 1879 

 

Expandable Polystyrene Operations 	 

26.11.19.19 	 

7-3-95 	 

22:13 Md R 970 

 

Commercial Bakery Ovens 	 

26.11.19.21 	 

7-3-95 	 

22:13 Md R 970 

 

Vinegar Generators 	 

26.11.19.22 	 

8-11-97 	 

24:16 Md R 1161 

 

Leather Coating 	 

26.11.19.24 	 

8-11-97 	 

24:16 Md R 1161 

 

Explosives and Propellant Manufacturing 	 

26.11.19.25 	 

8-11-97 	 

24:16 Md R 1161 

 

Reinforced Plastic Manufacturing 	 

26.11.19.26 	 

8-11-97 	 

24:16 Md R 1162 

 

Marine Vessel Coating Operations  	 

26.11.19.27 	 

10-20-97 	 

24:21 Md R 1453 



9.2 Stationary Source Thresholds

  

Under the moderate designation for the 8-hour ozone standard, the new
source review threshold is 50 tons per year VOC and 100 tons per year
NOx.  Maryland is committed to maintaining the Cecil County new source
review threshold at 25 tons per year for both VOC and NOx.

 

10.0  Contingency Measures

10.1  Contingency Overview 

The Clean Air Act requires States containing nonattainment areas to
adopt contingency measures that will take effect without further action
by the State or EPA upon a determination by EPA that an area failed to
demonstrate Reasonable Further Progress (RFP) or to timely attain the
applicable National Ambient Air Quality Standards (NAAQS), as described
in section 172(c)(9).

10.2  Contingency Emission Reductions for RFP Demonstration 

The Act requires the State to adopt specific contingency measures that
will take effect without further action by the State or the EPA if the
State fails to demonstrate VOC/NOx emission reductions by an additional
3% per year from 2002 through 2009 in accordance with Rate of Further
Progress Demonstrations.

The contingency measures identified by the State must be sufficient to
secure an additional 3% reduction in ozone precursor emissions in the
year following the year in which the failure has been identified. If the
shortfall is less than 3%, a contingency measure need only cover that
smaller percentage. If the shortfall is greater than 3%, the State, in
an annual tracking report to EPA, must either identify the additional
actions it will take to cure the shortfall before the next milestone or
maintain a reserve of contingency measures capable of covering a
shortfall greater than 3%. Early implementation of an emission reduction
measure to be implemented in the future is acceptable as a contingency
measure.

The RFP contingency requirement may be met by including in the SIP a
demonstration of 18% RFP and by attributing the additional 3% reduction
above the 15% requirement to specific measures. As shown in the Tables
10.1 below, the Maryland portion of the Philadelphia - Wilmington -
Atlantic City, PA - DE - MD - NJ can demonstrate 18% RFP.

Table 10.1:	RFP Contingency Measure Calculation

RFP Contingency Measure Calculation

Cecil County, MD Nonattainment Area

VOC Emissions

 	 	Formula	Tons/Day

A	2002 Base Year Inventory	 	60.52

B	Biogenic Emissions	 	42.94

C	2002 Rate-of Progress Base Year Inventory	A - B	17.58

D	FMVCP/RVP Reductions Between 2002 and 2008	 	0.69

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
16.89

F	Percent Emission Reductions for RFP

0.0700

G	Emission Reductions Required Between 2002 & 2008	E * F	1.18

H	Target Level for 2008  [TL(2008)]	C - D - G	15.71

I		Contingency Percentage

3.00%

J	Contingency Emission Reduction Requirements	D * I	0.51

K	Contingency Target Level (15% + 3% Contingency)	H - J	15.20

L	2008 Controlled Emission Level Obtained

14.65



RFP Contingency Measure Calculation

Cecil County, MD Nonattainment Area

NOx Emissions

 	 	Formula	Tons/Day

A	2002 Base Year Inventory	 	17.40

B	Biogenic Emissions	 	0.00

C	2002 Rate-of Progress Base Year Inventory	A - B	17.40

D	FMVCP/RVP Reductions Between 2002 and 2008	 	2.19

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
15.21

F	Percent Emission Reductions for RFP

0.0800

G	Emission Reductions Required Between 2002 & 2008	E * F	1.22

H	Target Level for 2008  [TL(2008)]	C - D - G	13.99

I		Contingency Percentage

0.00

J	Contingency Emission Reduction Requirements	D * I	0.00

K	Contingency Target Level (15% + 3% Contingency)	H - J	13.99

L	2008 Controlled Emission Level Obtained

11.05



Surplus Reductions from Existing Measures

Some emission control strategies listed to meet the 2008 target level
are expected to result in more emission reductions than are needed to
meet the requirements. If other measures fail to meet expected
reductions, the excess from the following measures will be used to make
up the difference:

NONROAD MODEL

OTC - Portable Fuel Container Phase 1 and Phase 2

OTC - Architectural Surface Coatings

OTC – Commercial and Consumer Products

Railroad Locomotives Tier 2

On-Road MOBILE

10.3  Contingency Emission Reductions for Failure to Attain 

The Clean Air Act requires nonattainment areas to implement control
measures necessary to meet the federal air quality standards.  Through
analysis and modeling a state demonstrates attainment based the
implementation of a State Implementation Plan.  If a nonattainment area
does not attain the federal standard by the prescribed attainment date
then the nonattainment area is required to implement contingency
measures within one year of a federal register notice that the area did
not meet its attainment date.  

The attainment date for the Philadelphia Nonattainment Area including
Cecil County is June 15, 2010.  However, attainment of the standard is
based on the three-year design value that averages the ozone seasons of
2007, 2008, and 2009.  Therefore, the 2009 design value is the marker by
which attainment will be judged.  States will be notified if they did
not meet the 8-hr Ozone standard in 2010 based on a review of the 2009
design value.  One year from the date of notification the identified
contingency measures must be in fully implemented.  This means that
contingency measure must provide emission reductions in the 2011
timeframe to meet the contingency requirements.     

The attainment contingency requirement can be met by demonstrating that
emission reduction benefits from specific measures occurring after 2009
meet or exceed 3% of the Adjusted 2002 Base Year inventory. As shown in
the Tables 10.2, 10.3, and 10.4 below, Cecil County can demonstrate
compliance with the Failure to Attain Contingency Measure Requirements. 
The future benefits from existing control measures, calculated between
2011 and 2009, are shown in Table 10.2.  The VOC reduction requirement
is shown in Table 10.3.   The NOx reduction requirement is shown in
Table 10.4.

Table 10.2:	Failure to Attain Contingency Measure Benefit Calculation

Failure to Attain Contingency Measure Benefit Calculation

Cecil County, MD Nonattainment Area

Future Benefits from Existing Measures

	2009 Controlled

Emissions

2011 Controlled

Emissions

Benefits

(tpd)

Control Measure	VOC	NOx

VOC	NOx

VOC	NOx

OTC – PFC	0.42	0.00

0.26	0.00

0.15	0.00

Nonroad Model	7.20	2.14

6.69	2.05

0.50	0.09

Railroads (Tier 2)	0.03	0.43	 	0.03	0.41

0.00	0.02

TOTAL BENEFITS 





	0.65	0.11



Table 10.3:	Failure to Attain VOC Emission Reduction Requirement
Calculation

Contingency Measure Calculation

Cecil County, MD Nonattainment Area

VOC Emission Reduction Requirements

 	 	Formula	Tons/Day

A	2002 Base Year Inventory

60.52

B	Biogenic Emissions

42.94

C	2002 Rate-of Progress Base Year Inventory	A - B	17.58

D	FMVCP/RVP Reductions Between 2002 and 2008

0.69

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
16.89

F		Contingency Percentage

2.50%

G	Contingency Emission Reduction Requirements	E * F	0.42

	REDUCTIONS ACHIEVED

0.65



Table 10.4:	Failure to Attain NOx Emission Reduction Requirement
Calculation

Contingency Measure Calculation

Cecil County, MD Nonattainment Area

NOx Emission Reduction Requirements

 	 	Formula	Tons/Day

A	2002 Base Year Inventory

17.40

B	Biogenic Emissions

0.00

C	2002 Rate-of Progress Base Year Inventory	A - B	17.40

D	FMVCP/RVP Reductions Between 2002 and 2008

2.19

E	2002 Adjusted Base Year Inventory Calculated Relative to 2008	C - D
15.21

F		Contingency Percentage

0.50%

G	Contingency Emission Reduction Requirements	E * F	0.08

	REDUCTIONS ACHIEVED

0.11



As identified above there are 0.03 tpd of additional credit under the
NOx contingency plan.  As stated in Section 8.2, the MDE has allocated
0.02 tpd of this additional NOx to the 2009 NOx mobile budget.

11.0 Weight of Evidence Attainment Demonstration

The approach to attainment demonstration taken by MDE considers the
cumulative body of science with respect to ambient ozone concentrations
in the Baltimore 8-hour ozone non-attainment area.  MDE has employed an
ensemble approach to the attainment demonstration comprised of numerous
technical tools including rigorous data analysis, observations, and
modeling.  The weight of evidence produced by MDE features contributions
from institutions with a plethora of expertise in air quality,
atmospheric chemistry, and meteorology.  The institutions include The
University of Maryland Department of Atmospheric and Oceanic Science,
The Pennsylvania State University Department of Meteorology, The Howard
University Department of Physics, The University of Maryland at
Baltimore County Department of Physics, and The University of Maryland
Center for Environmental Science at Frostburg University.  As academic
centers, these institutions have published peer-reviewed journal
articles in periodicals of the atmospheric sciences.  MDE has relied
heavily on such publications for the analysis presented in the weight of
evidence.  Highly qualified, private consultants, including SAIC and
Environ provided additional contributions to the weight of evidence.  

An important distinguishing characteristic of the attainment
demonstration approach taken by MDE is not only the overall assembly of
analysis, observations, and modeling, but also the ensemble focused
solely on three-dimensional photochemical grid modeling.  Whereas the
EPA guidance emphasizes a single design value from a single modeling
simulation as the core of an attainment demonstration, the preponderance
of atmospheric science knowledge shows intelligent use of models should
consider all of the model uncertainties and biases, include multiple
simulations, and ultimately produce, not a single design value, but a
range of predicted future design values.  The ensemble approach is
analogous to how a meteorologist determines a precipitation forecast. 
The meteorologist looks at multiple meteorological models, considers
uncertainties and biases of each model, reviews circumstances the model
may not account for, determines if there are any other outside
extenuating factors, and finally ascertains a range of possible
outcomes.  This range is then delivered to the forecast audience. 
Similarly, the MDE ensemble approach to weight of evidence modeling
provides a comprehensive evaluation of model performance for various
scales of time, area, height, and chemistry.  Based on the sensitivity
of the model under the evaluation schemes, a range of predicted 2009
8-hour ozone design values is forecasted for every monitoring site in
the Philadelphia non-attainment area.  

The net result of applying techniques of data analysis, observations,
and modeling in the weight of evidence is a favorable indication for
successfully attaining the 8-hour ozone NAAQS in 2009 for Cecil County,
Maryland and for the area presently classified as the Philadelphia
non-attainment area.  Figure 11.0.1 shows the weight of evidence range
of probable design values for 2009 for all sites in the state of
Maryland.  No single value is provided for each site; instead, a range
is provided in order to more accurately represent the expected accuracy
of the modeling exercises.  The fundamental knowledge gained through
comparisons to observations, analysis of trends, and sensitivity model
runs resulted in the ranges put forth in Figure 11.0.1.  All sites in
Maryland show attainment of the 8-hour ozone NAAQS of 85 ppb for 2009.  





Figure 11.0.1	Range of probable 2009 8-hour ozone design values for all
sites in Maryland

11.1  Ambient Air Monitoring Measurements and Trends

Measurements from surface monitoring stations provide the most
fundamental indication of air quality improvement in the Baltimore
non-attainment area.  Basic trends of ozone from the network of monitors
show continuously improving air quality Maryland and the Baltimore NAA
with respect to multi-year design values, annual exceedance day counts,
24-hour daily peak concentrations, single-hour concentrations, spatial
area, warm weather days when ozone is usually highest, and finally with
respect to ozone precursor trends.

The Ambient Monitoring Network

MDE operates a relatively dense network of ozone monitoring stations,
which has enabled the collection of high resolution ozone data on
various scales of time and space.  Figure 11.1.1 shows maps of the
ambient ozone monitoring network for Maryland, the Mid-Atlantic, and the
Eastern U.S.  Despite the small size of Maryland, MDE operates a
relatively dense network of ozone monitors.  Comparing the spatial
density of monitoring sites on a wider domain of the Mid-Atlantic region
shows that Maryland has no large expanses without monitors, like
Virginia, West Virginia, and Pennsylvania.  An even larger perspective
over the entire Eastern U.S. reveals that Maryland is actually covered
by one of the more dense monitoring networks due to the required
monitoring associated with the cluster of large metropolitan areas
extending from Richmond, VA through New York, NY.  

The code of federal regulations requires four ozone sites for a
metropolitan statistical area of  > 10 million people for an 8-hour
ozone non-attainment area (40CFR58 Appendix D §4.1).  MDE currently has
seven ozone sites deployed in the Baltimore NAA and one site in the
Cecil County, Maryland portion of the Philadelphia NAA.  Due to
logistical reasons, slight changes are made in the deployment of sites
over the years, such as the unavoidable relocation of the Fort Meade
monitoring site due to the U.S. military’s need for additional space
on the grounds of the Fort Meade military post.  MDE was fortunate to
find a new location for the site at Beltsville, where inter-agency
collaborations and opportunities for long-term studies are more viable. 
On the whole, the number of sites remains relatively constant.  

Ozone Trends

Ozone concentrations exhibit an improving air quality trend on multiple
temporal scales.  Perhaps the simplest regulatory measure of improving
air quality is the downward trend in 8-hour ozone design values for the
sites in Maryland.  Design values offer the benefit of a multi-year
metric, which removes the statistical bias of single high values by
taking the fourth highest value of three consecutive years and averaging
those values together.  Figure 11.1.2 displays the decreasing trend of
8-hour ozone design values in Maryland.  The trend is a good fit to the
data with an R2 of ~0.4 and a slope of –0.7 ppb / year.  The last
three years highlight the disproportionate benefit of the NOx SIP Call
when regional controls were put in place between 2003 and 2004.  

The downward trend in 8-hour ozone concentrations on an annual basis is
highlighted in Figure 11.1.3 by showing the number of 8-hour ozone
exceedance days per year.  This trend is also a good fit with an R2 of
~0.5 and a steeper declining slope of –1.4 days / year.  Since 2002,
an average of 17.5 days per year have experienced 8-hour ozone
concentrations ( 85ppb or in other words 2.5 weeks, which is a sharp
contrast to the 2 months worth of exceedance days, which existed in the
1980s.  

Taking yet another step down in temporal scales brings the study of
trends to the daily scale.  Average daily peak 8-hour ozone is shown in
Figure 11.1.4.  In order to see a clearer picture of the trends without
the noise of short-term fluctuations, the data are grouped in four-year
bins.  The methodology of choosing bins is carried out in reverse
chronological order, beginning with the first four-year bin of
2003-2006, the NOx SIP Call years.  Scientific consensus is that ozone
concentrations in the eastern U.S., outside of large urban areas, are
NOx-limited.  As a result, reductions in region-wide NOx emissions
should reduce the overall background ozone concentrations.  Local
emissions and photochemistry will still lead to short-term spikes in
ozone, often ( 85 ppb, but these spikes will occur on top of a lower
base-level of ozone.  The magnitude of each individual ozone spike
should also have reduced amplitude from the base-level.  Such a change
in the base-level of ozone was created by the NOx SIP Call and is
demonstrated in Figure 11.1.4.  







Panel C – Mid-Atlantic Ozone Network	





Figure 11.1.1	Maps of ozone monitoring sites (inverted green triangles).
 Panels A, C, and D show sites active during 2006.  Panel B shows sites
active during the period of 2002-2006.  There are 17 ozone monitoring
sites in the state of Maryland, a dense network for a relatively small
state.



 

Figure 11.1.2	Trend in 8-hour ozone design values per year for all
Maryland sites.

	The declining trend is a sign of improving air quality.  

 

Figure 11.1.3	Trend in 8-hour ozone exceedance days per year for all
Maryland sites.  The declining trend is an indicator of improving air
quality.

Figure 11.1.4	Trends in average daily peak 8-hour ozone for all Maryland
sites binned by four-year periods.  The red brace and arrow indicate
improving air quality shown by the decreasing trend of average daily
peak 8-hour ozone.  Each trend line is fourth order.  

Continuing in reverse chronological order, each of the prior bins also
consisted of a four-year period for the sake of consistency.  The most
important feature of Figure 11.1.4 is the steady decline in the trend of
each bin, indicated by the red arrow.  The part of the summer when peak
ozone concentrations occur (June-August) is exactly when the greatest
benefit is seen with reductions in the daily peak 8-hour ozone.  The
improving trend in 1999-2002 (green) is partially due to meteorology
because the summers of 2000 and 2001 were not conducive to photochemical
formation as temperatures were cooler than normal, precipitation was
more prevalent, and the synoptic scale systems rarely created long-lived
high pressure centers over the South Eastern U.S. which typically plays
a large role in high ozone episodes.  The improving trend in 2003-2006
(blue) shows another marked decrease in ozone values, a sign of the
valuable impact of the NOx SIP Call.

Not only have ozone concentrations been steadily declining during the
part of the summer when ozone production is greatest, but ozone
concentrations have also been steadily declining during the part of each
day when ozone production is greatest.  Being a photochemical pollutant,
ambient ozone concentrations reach their peak during the afternoon when
the sun angle is high and temperatures are at their warmest.  Figure
11.1.5 shows the diurnal trend in ozone from 1993 to 2006.  The years
are binned by 3-year rolling averages in order to eliminate the noise of
hourly fluctuations present in the raw data.  The steady progression
from each rolling average to the next shows an undeniable improvement of
air quality.  The red arrow indicates the decline of ozone
concentrations.  The last three rolling averages (yellow, gray, black)
experienced a distinct decline in magnitude of hourly ozone after the
NOx SIP Call.  

 

Figure 11.1.5	Trend in diurnal ozone by 3-year rolling averages for all
Maryland sites from the summers (April 1 – October 31) of 1993 through
2006.  The red brace and arrow indicate improving air quality shown by
the decreasing trend of peak mid-day hourly concentrations.

While various temporal scales have shown declining concentrations of
ozone over the year, one of the most concise methods for displaying
year-to-year improvement in air quality is to map interpolated ozone
concentrations across a wide domain.  Figure 11.1.6 shows the trend in
the spatial extent of 8-hour ozone design values ( 85ppb from 1995 to
2006.  Improving air quality is exhibited by the steady decrease of the
spatial extent as well as the magnitude of design values that are (
85ppb.  The maps indicate the region as a whole has been experiencing
continuous progress towards attaining the NAAQS for ozone.  Substantial
improvements are observed after 2004 as indicated by the shrinking
spatial extent of the area ( 85ppb and the decrease in regional maximum
8-hour ozone design values.  The maps were created using Tension Spline
interpolation in ESRI ArcGIS with the Spatial Analyst extension. 
Tension Spline interpolation enforces precise representation of all
observed measurements and employs smooth contours that avoid falsely
characterizing the spatial extent of the design values.  As with all
interpolation techniques there are inevitably some portions of the
domain that will be misrepresented by either over or under estimations. 
Portions of the domain over the Chesapeake Bay appear to have estimates
on the high end, weighting the Washington-Baltimore corridor sites more
heavily than the DEL-MAR-VA peninsula where sites are in attainment. 







  Figure 11.1.6	1995-2006 improving trend exhibited by decreasing
spatial extent and magnitude of 8-hour ozone design values ( 85ppb.

  

The approach to trends thus far has focused entirely on the ozone
concentrations themselves.  A more comprehensive look at ozone trends
must also consider meteorology and precursors.  Ozone is a photochemical
pollutant and as such, it is highly dependent upon meteorological
conditions.  

Temperature Adjusted Ozone Trend

The data shown in Figure 11.1.7 provide insight to the trend of 8-hour
ozone with respect to temperature. 

 

Figure 11.1.7	Improving air quality in Maryland is shown by the downward
linear trend (black line) of the difference between (blue line) the
number of 8-hour ozone exceedance days per year (green bars) and the
number of days with a daily maximum temperature > 90(F per year at BWI
(red bars).  The time period is 1981-2006.

Temperature is the single strongest environmental predictor of ozone
concentrations, as such there has historically been a strong correlation
between the number of 8-hour ozone exceedance days per year and the
number of days with a daily maximum temperature > 90(F per year at BWI. 
In fact, in the early 1980’s the number of exceedance days was
typically double the number of 90(F days.  This statistic has steadily
changed through, so that in 2006 the ratio was the exact opposite with
the number of 90(F days doubling the number of exceedance days.  The
trend in the difference between the two counts (black line) has an R2 of
0.6 and a downward slope of –1.3.  Despite stable numbers of 90(F
days, ambient ozone concentrations continue to experience a continuous
downward trend reflecting improvements in air quality.  Besides ozone
itself and meteorology, the third important subject which should be
explored by trends is precursors to ozone formation.  

Ambient Ozone Precursor Trend

As described in Chapter 2, the precursors to ozone formation include
VOCs and NOx.  VOCs are a somewhat difficult to depict in terms of
simple trends because the list of VOCs is so large.  MDE collects 56
species of VOCs as part of the PAMS (Photochemical Assessment Monitoring
Sites) network and a separate list (with some commonality) of 61 Toxic
VOCs.  VOC measurements have uniformly experienced declines in
concentrations since 1994 due to the reforumulated gasoline rule,
hydrocarbon reductions for Ozone, and also some associated benefits
since 1990s restrictions on CFC (chlorofluorocarbon) emissions.  NOx on
the other hand, is more simply analyzed and it is widely available. 
Based on observations, ozone concentrations vary linearly with
integrated upwind NOx emissions (Appendix G-1).  A given percent
reduction of NOx should result in an equal percent reduction of ozone. 
NOx is measured by the same trace gas instrumentation used to
simultaneously measure ambient NO and NO2.  NO2 is commonly measured to
show compliance with the NO2 NAAQS.  Figure 11.1.8 displays the
decreasing trend of NOx for the BNAA since 1993.

 

Figure 11.1.8	Trend in diurnal NOx by 3-year rolling averages for all
sites in Maryland from the summers (April 1 – October 31) of 1993
through 2006.  The red brace and arrow indicate improving air quality
shown by the decreasing trend of peak hourly concentrations.  Instrument
calibration occurs during the data gap at 2:00 AM EST.  

Supplemental Monitoring Initiatives

Monitoring in order to show compliance with the NAAQS and in order to
quantify exposure while protecting the health of the public and
environment, is the first goal of ambient air quality monitoring.  As
such, the CFR requirements focus on monitoring for exposure and
monitoring for background concentrations.  MDE takes great care to go
beyond the CFR requirements to ensure ambient concentrations are being
measured in rural, suburban, and urban locales.  17 ozone monitoring
sties are operated in Maryland and 7 of them lie within the Baltimore
NAA where only 5 monitors are required by the CFR.  While monitoring for
compliance and exposure does allow the state to ensure healthy air
quality is maintained, monitoring for compliance and exposure does
little to explain why poor air quality episodes develop.  In fact,
compliance and exposure monitoring tells virtually nothing about the
source of an air mass and where the emissions originated.  In order to
discover where poor air quality is coming from, monitoring has to be
conducted with an eye towards culpability.  

MDE dedicates large resources to monitoring for culpability in order to
discover the origins of poor air quality episodes, so that the problem
may be addressed at its source.  Tracking the history of air parcels
involves taking measurements from above the ground surface and deploying
instrumentation into the atmosphere at varying heights.  In this vane,
MDE has created several atmospheric profiling initiatives including
various platforms:  aircraft, ozonesonde balloons, RADAR (Radio
Detection And Ranging), LIDAR (LIght Detection And Ranging), and
high-elevation, mountain-top sites.  Figure 11.1.9 shows photographs of
the first four platforms.

Panel A

	Panel B

 



Panel C

	

Panel D



Figure 11.1.9	Supplemental atmospheric profiling initiatives supported
by MDE.

	A. Aircraft, B. Ozonesonde Balloon, C. RADAR, D. LIDAR

Data collected from these projects allow MDE to understand interstate
pollutant transport and to state the case for equitable emission control
strategies across state boundaries.  The data products are priceless
tools for examining model performance, analyzing air quality episodes,
and educating the general public.  The remainder of this section is
dedicated to describing each of these supplemental monitoring
initiatives, each of which serves an important role in quantifying the
degree of interstate air pollutant transport coming into Maryland.  

Aircraft

MDE has contracted with the University of Maryland since 1995 to make
aircraft profile spirals over locations throughout the Mid-Atlantic and
as far away as North Carolina and Vermont.  Measurements include trace
gases and aerosol characteristics from 100m – 4,000m in altitude in
variable intervals with 10-second resolution.

Ozonesonde Balloons

MDE has contracted with Howard University since 2005 to make ozonesonde
balloon profiles over Beltsville, Maryland.  Measurements include
temperature, relative humidity, wind speed, wind direction, and ozone
from 0m – 32,000m in altitude at variable intervals with 1-second
resolution.  The ozonesonde is made up of two paired modules:  A
wet-chemistry ozone-sensing module and a GPS rawinsonde
meteorology-sensing module.

RADAR

MDE owns and operates two radar wind profilers.  One was originally
deployed in 1998 at Fort Meade, Maryland.  It was subsequently moved to
Beltsville, Maryland in 2005.  During the same year a second radar wind
profiler was purchased by MDE and deployed at the Piney Run monitoring
site near Frostburg, Maryland.  The RADAR measures wind speed, wind
direction, and virtual temperature from 120m – 4,000m in altitude in
intervals of 100m with 15-minute resolution.  RADAR emits
electromagnetic energy and detects shifts in the backscattered energy,
which mathematically translate to information about the winds and
temperature in the atmosphere.

LIDAR

MDE has contracted with the University of Maryland at Baltimore County
since 2005 to measure aerosols over Catonsville, Maryland.  Measurements
include aerosols scattering from 0m – 10,000m in altitude in 1m
intervals with 1-minute resolution.  LIDAR emits laser light and detects
changes in the backscattered light which mathematically translate to
information about the aerosol content and dynamics in the atmosphere.  

High-Elevation Mountain-Top Sites

MDE deployed a high-elevation, mountain-top surface monitoring site in
2004 called Piney Run, located near Frostburg, Maryland.  The site sits
along the western boundary of Maryland in a rural setting with minimal
local emissions.  The site serves as a front-line indicator of westerly
transport arriving in Maryland and fills a gap in high elevation
monitors between Methodist Hill, Pennsylvania, and Shenandoah National
Park, Virginia.

11.2  The Challenge of Interstate Transport

In terms of geography, Maryland enjoys the benefit of many natural
resources.  The state’s location on the east coast provides
considerable shoreline along the Atlantic Ocean, a wealth of fresh water
resources in the Chesapeake Bay, and in the west, high elevation access
to the Appalachian Mountains.  While there are tremendous benefits to
the state’s geographical location; there is a major challenge in terms
of air quality:  downwind interstate air pollution transport.  Maps of
the four main patterns associated with air pollution transport into
Maryland are provided in Figure 11.2.1.  

Depending largely on the placement and severity of the Bermuda High
Pressure Center, the worst ozone episodes are almost always associated
with one of the four main transport patterns: Along Corridor, Northerly,
Westerly, and Pre-Frontal.  The concentration of ozone in each of the
upwind areas determines just how severe of an impact the interstate air
pollution transport will have on air quality in Maryland.  All four of
the transport patterns have one thing in common:  a westerly transport
component.  Westerly transport is well documented in peer-reviewed
publications.  One such description of the role of transport in regional
ozone episodes was described by Taubman:  “Regional high ozone events
often occur when the Bermuda high strengthens and extends west into the
eastern United States.  Subsidence east of the ridge induces clear
skies, high temperatures, atmospheric stability, and stagnant winds. 
These factors enhance photochemistry and inhibit vertical mixing,
thereby contributing to increased local concentrations of ozone. 
Circulation around the ridge results in westerly transport of ozone and
ozone precursors from the Midwest to the eastern United States, where
they combine with local emissions."

 



 



 



 



Figure 11.2.1	The four main synoptic meteorology patterns associated
with transport of air pollution into Maryland.  The colored background
represents temperature.  The pressure is indicated by white isobars with
“H” at the center of high pressure systems.  Winds are shown as
small white arrows and general circulation is shown as large black
arrows.  

Westerly Transport

Major upwind ozone precursor sources lie just beyond the borders of
Maryland in states such as West Virginia, Virginia, Pennsylvania, and
Delaware.  Long-range interstate transport also extends beyond the
adjoining states to states such as Ohio, Michigan, Kentucky, North
Carolina, and Georgia.  The direction of transport coming into Maryland
includes just about every compass direction, but the primary concern is
transport from the west where the dense number of point sources along
the Ohio River Valley has a direct impact on Maryland’s air quality on
a regular basis.  

As the atmosphere exhibits no boundaries in space or time, interstate
pollutant transport occurs continuously throughout the diurnal cycle. 
During the daytime when the atmospheric column is well mixed, it is
difficult to apportion the relative impact of long-range emissions
versus local emissions.  However, during the night when the atmosphere
stratifies, pollutant concentrations can sometimes become isolated above
the ozone-poor, nocturnal boundary layer in a layer referred to as the
“residual layer”.  Figure 11.2.2 shows the development of the
nocturnal residual layer where interstate transport may be frequently
observed.  

Figure 11.2.2	Diagram of the atmospheric boundary layer.  The nocturnal
atmosphere stratifies into a residual layer aloft where interstate
pollutant transport may be measured.  

At night during the summer when the surface cools faster than the air
above it, a temperature inversion will develop that stratifies the lower
planetary boundary layer.  Below the inversion dry deposition with the
surface, brings ozone concentrations to minimum in the “ozone-poor
layer”.  Above the temperature inversion, pollutants that were emitted
throughout the day and pollutants that continue to be injected high into
the atmosphere by tall point sources with hot buoyant plume rise, are
trapped in the residual layer.  The boundary between the residual layer
and the ozone-poor layer creates a stratified atmosphere and pollutants
travel above with laminar characteristics through the residual layer.  

The residual layer creates an opportunity to observe interstate
transport before local emissions contribute to the total pollutant load.
 The obstacle is finding a way to take measurements from within the
residual layer, which is typically 300-600m above the ground surface. 
MDE has utilized three separate measurement platforms to make in-situ
vertical profile observations of westerly transport within the residual
layer.  These include high elevation surface monitoring sites, ozonsonde
balloons, and aircraft.  A case is presented here from August 13, 2005
which shows the detection of residual layer ozone transported from
upwind locations into the Maryland air shed.  August 13, 2005 did
experience exceedances of the 8-hour ozone NAAQS in the Baltimore
non-attainment area; however, there are many other cases when higher
ozone concentrations have been measured.  The case is chosen as a case
study primarily because of the balloon and aircraft data availability
for the episode.  The synoptic circumstances observed do represent the
conditions that are frequently present during extended ozone episodes
such as the kind that result in being relevant to design value
calculations.  The fact that conditions for the case were so
theoretically perfect for an ozone episode is precisely why the air
quality forecasters recommended the balloons and aircraft be put into
operation for the period.  

On August 13, 2005 a high pressure center was in place over the
southeastern United States (Figure 11.2.3, Panel A).  



Figure 11.2.3	A.	Synoptic analysis from 7:00 AM EST of August 13, 2005. 
High pressure over the south east United States, an approaching cold
front, and a lee-side trough all serve as strong indicators for an ozone
episode.  

	B.	Visible Satellite imagery from 10:45 AM EST of August 13, 2005. 
Cloud cover is associated with the cold front and haze is present over
much of the Mid-Atlantic.

This high-pressure system created clockwise circulation with streamlines
crossing the Ohio River Valley and carrying its point sources emissions
into Maryland.  The high-pressure circulation was reinforced by an
approaching cold front (blue line with triangles) which served to
suppress horizontal ventilation to the NorthEast.  In addition a
lee-side trough was analyzed east of the Appalachian Mountains (dashed
orange line) which typically coincides with an enhanced mesoscale
southwesterly flow within the residual layer called the Nocturnal Low
Level Jet.  Visible satellite imagery (Figure 11.2.3, Panel B) shows
haze over much of the Mid-Atlantic and cloud cover associated with the
cold front.  There are three measurement platforms, which successfully
observed residual layer transport of ozone on August 13, 2005.  The
first platform described is the network of surface monitoring sites
including some sites at high elevation.  

Demonstration of Residual Layer Westerly Transport using High Elevation
Monitors

MDE forecasts air quality for the state of Maryland using not only the
network of surface ozone monitors owned and operated by MDE, but also
several monitors in surrounding states including Delaware, the District
of Columbia, Pennsylvania, Virginia, and West Virginia.  Sites from the
other states serve a supplementary function in providing data where the
geographical boundary of Maryland has made it impractical to make heavy
deployment of monitoring sites.  Figure 11.2.4, Panel A provides a map
of every sites used by the MDE air quality forecasting program during
the summer of 2005.  The topography of the map reveals that three of the
sites indicated by colored triangles lie at high elevation.  In fact the
elevation of those three sites is approximately double the height of any
other site in the domain.  The three high elevation sites are Piney Run,
Maryland, Methodist Hill, Pennsylvania, and Shenandoah National Park,
Virginia.  Figure 11.2.4, Panel B shows a plot of hourly ozone
concentrations for August 13, 2005 for every site shown in the Panel A
map.  During the night time hours of 2:00 AM – 7:00 AM EST the three
high elevation monitors exhibit a remarkably different sample of ozone
concentrations from the rest of the sites.  In fact during the night
hours, the high elevation monitors registered concentrations of ~55ppb. 
On average, that is more than double the ~20ppb concentrations sampled
by the low-lying sites in the ozone-poor layer of the atmosphere.  Piney
Run (red triangle) appears to have initially begun to lie within the
ozone-poor layer of the boundary layer from 12:00 AM – 2:00 AM EST,
but it quickly soon returned to higher concentrations of ozone as the
residual layer settled down to the elevation of the monitoring station. 


These important high elevation measurements show that when the morning
mixing begins, residual layer ozone may have an immediate contribution
of 55ppb to the daily ozone concentrations in Maryland.  This creates a
situation in Maryland where an ozone allotment of only 30ppb may be
produced locally before the NAAQS will be exceeded for the day.  



Figure 11.2.4	A.	Topographical map of Maryland and the surrounding
states with an overlay of ozone monitoring sites used for Maryland air
quality forecasting.  Topographical shades of green represent low
elevations and topographical shades of brown represent high elevations. 


		Black Circles:		Low Elevation Monitoring Sites ( < 365m )

		Colored Triangles:	High Elevation Monitoring Sites

				Red  = 781m, Green = 630m, Blue = 1,072m

 Hourly Ozone on August 13, 2005 for all sites shown in Panel A.  

Demonstration of Residual Layer Westerly Transport using Ozonesonde
Balloons

The second platform used to measure residual layer ozone transport for
the case of August 15, 2005 was the ozonesonde balloon launched from
Beltsville, Maryland.  In fact, two balloons were launched during this
period, one at 6:00 AM EST and one at 2:00 PM EST.  At the 6 AM launch
(Figure 11.2.5) the nocturnal inversion is pronounced at ~ 400m in the
temperature profile (red).  The wind speed profile (blue) shows a 10m/s
local maxima between 300-1000m indicating the presence of a nocturnal
low level jet.  The wind direction (purple) confirms another jet
characteristic, veering winds from the surface to the top of the jet at
1000m.  The ozone profile (black) shows minor increases in ozone within
the LLJ.  

Figure 11.2.5	Ozonesonde balloon launch at 6:00 AM EST on August 15,
2005 from Beltsville, Maryland.  Ozone is in black, temperature is in
red, wind speed is in blue, and wind direction is in purple.  

Demonstration of Residual Layer Westerly Transport using Aircraft

The third platform used to measure residual layer ozone transport for
the case of August 15, 2005 was the aircraft, which made several spirals
along the western boundary of Maryland and over locations south of
western Maryland.  The spirals were flown over Luray, VA at 10:00 AM
EST, Winchester, VA at 11:00 AM EST, and Cumberland, MD at 11:45 AM EST.
 Figure 11.2.6  shows profiles from over the three locations in three
panels.  Panel A shows concentrations of almost 80ppb in the nocturnal
residual layer from 1400-1800m in height.  SO2 concentrations are
correspondingly large over the same height; however, CO shows its
largest concentrations near the surface, where mobile emissions are
trapped beneath the boundary layer.  

Panel A

10:00 AM

EST

Luray

VA



Panel B

11:00 AM EST

Winchester



Panel C

11:45 AM EST

Cumberland



Figure 11.2.6	Aircraft spirals on August 15, 2005.  Ozone is in black,
temperature is in red, SO2 is in orange, and CO is in yellow.  

Similar structure is observed in Panels B and C as the day progresses,
but with increased mixing of the high concentrations which broadens the
height of the localized maxima to 700-2100m in height.  

Animated Google Earth Movie of Westerly Transport

All of the observations recorded by the three platforms presented in
section 11.2 are incorporated in an animated movie MDE has created for
the August 15, 2005 westerly transport case.  Additional profiles are
also included for later in the day showing the impact of transport on
the eventual concentrations of ozone in the major metropolitan corridor
including Washington, DC, Baltimore, MD, and Philadelphia, PA.  HYSPLIT
24-hour back-trajectories are plotted for every vertical profile using
the NOAA EDAS 40km data archive and modeled vertical velocity. 
Additionally, the 1999 EPA NOx point source emissions inventory was used
to plot all NOx sources that emit 25 tons per day or more of NOx. 
Counts of the number of point sources per state that emit 25 tons per
day or more of NOx are also presented.  The animated movie was created
using Google Earth Professional Version and was recorded and burned to
DVD.  Appendix G-2 contains the DVD.  

Nocturnal Low Level Jet Transport

In addition to the large-scale westerly transport resulting from the
four synoptic meteorological patterns described at the beginning of
section 11.2, a smaller-scale transport mechanism created by mesoscale
meteorological conditions also has a significant impact on poor air
quality episodes in Maryland.  This mechanism is the nocturnal low-level
jet (NLLJ) which flow from SW to NE in the Mid-Atlantic region, parallel
to and on the lee-side of the Appalachian Mountains.  Taubman describes
the NLLJ in simple terms:

“The NLLJ occurs between 12:00 AM and 6:00 AM EST and has the
following characteristics:

Generally located between 300 and 1000 m in altitude

South-Southwesterly wind maximum in the residual layer of 10–20 m/s

NLLJ “core” with wind speed maximum greater than those in the
underlying nocturnal boundary layer and those just above, but still in
the jet

Veering winds (turning from S to W) from the surface up through the NLLJ
core

The nocturnal boundary layer provides a low-friction surface over which
the jet can travel.  This phenomenon also seems to be orographically
derived, possibly resulting from the differential heating and pressure
gradients associated with sloping terrain on the lee-side of the
Appalachian Mountains.  Pollutant transport via the NLLJ is
disproportionately important during periods of stagnation when
geostrophic winds are light.”  Figure 11.2.7 shows the synoptic
weather analysis for August 5, 2005 at 7:00 AM EST.  Much like the
westerly transport example detailed in earlier sections, August 5, 2005
also had high pressure over the southeast U.S. with a cold front
approaching from the northwest.  The pink arrow indicates the
theoretical position of the NLLJ, based upon other field studies which
documented the presence of the NLLJ in New Jersey, Pennsylvania,
Maryland, Virginia, and North Carolina.

 

Figure 11.2.7	Synoptic weather analysis from August 5, 2005 at 7:00 AM
EST.  The pink arrow indicates the theoretical position of the NLLJ.  

The NLLJ is an important mechanism for transport for two reasons.  It
acts as a conduit for air pollutant transport and like westerly
transport, the residual pollutants within the NLLJ will mix down to the
surface when the nocturnal inversion breaks down.  Secondly, the NLLJ
creates turbulence between the ozone-poor nocturnal surface layer and
the ozone-rich residual layer during the night, which increases
nocturnal ozone exposure at the surface when benign ozone concentrations
would otherwise be expected.  There are three measurement platforms,
which successfully observed the NLLJ and associated ozone transport on
August 4-5, 2005.  In total, four independent measurements were made of
the NLLJ in this case:  RADAR, LIDAR, and two separate ozonesonde
balloons.  Figure 11.1.1 Panel A shows the location of the Beltsville
monitoring site where the RADAR is located and where the ozonesonde
balloons were launched.  The LIDAR is located in Catonsville, MD on the
campus of the University of Maryland at Baltimore County near the
intersection of three Maryland counties:  Baltimore County, Howard
County, and Anne Arundel County.  Both the RADAR and LIDAR platforms are
described simultaneously in this first portion of the case description.

 

Demonstration of Residual Layer NLLJ Transport using RADAR and LIDAR

The MDE RADAR in Beltsville, Maryland observed the August 4-5, 2005 NLLJ
for 8.5 hours beginning at 11:00 PM EST on August 4, 2005 and ending at
7:30 AM EST on August 5, 2005.  The top portion of Figure 11.2.8 shows a
time-height plot of wind observed by the RADAR.  Portions of the plot,
which fit the accepted fingerprints of a NLLJ are enclosed by the black,
amoeba-shaped line.  Wind speeds of 15 m/s, veering with height, were
observed throughout the jet, which was observed from 200-800 meters in
altitude.  

 

Figure 11.2.8	The top portion of the time-height plot depicts winds from
the RADAR at Beltsville, Maryland.  The bottom portion of the
time-height plot depicts aerosol scattering from the LIDAR at
Catonsville, Maryland.  The black, amoeba-shaped, line is drawn around
the portion of the RADAR data that fits the stereotypical
characteristics of a NLLJ.  The same black shape was also overlayed on
the LIDAR data.  The timing of two ozonesonde balloon launches from
Beltsville, Maryland are also overlayed in pink, dashed lines at their
respective launch times.  

The same black outline was overlayed on the LIDAR data in the lower
portion of Figure 11.2.8.  The outline provided an excellent qualitative
match to the portion of the LIDAR data exhibiting a signature of the
NLLJ, namely enhanced turbulent inhomogeneties and stratification at the
same heights and for the same period of time as the RADAR winds.  The
final piece of information in Figure 11.2.8 is the overlay of ozonesonde
balloons (pink dashed lines) at their respective launch times.  

Demonstration of Residual Layer NLLJ Transport using Ozonesonde Balloons

The data collected by the two ozonesonde balloons are displayed in
Figure 11.2.9.  Panel A shows the launch at 3:30 AM EST and Panel B
shows the launch at 7:30 AM EST.  Both launches revealed fast wind
speeds (blue profiles) in the jet and veering wind directions (purple
profiles).  In the earlier launch, the jet speed is 14 m/s with a jet
core from 200-800 m in altitude.  In the later launch, the jet speed is
10 m/s with a jet core from 250-500 m in altitude.  The black profiles
of ozone in each plot show a local maximum in ozone between 500-1000 m
in altitude.  The local ozone maxima appear to be associated with the
presence of the NLLJ.  Recent, unpublished work documents secondary
nocturnal maxima occurring during the night at surface monitors when the
presence of a NLLJ is confirmed.  The magnitude of the secondary
nocturnal ozone maxima has been measured as high as 30ppb when monitored
at the surface using 10-minute average data.  







Figure 11.2.9	Ozonesonde balloon data are shown as vertical profiles
through the atmosphere.  Radar winds are overlayed with the blue and
purple data points.  Two balloon launches took place on August 5, 2005. 


		A.	3:30 AM EST on August 5, 2005

		B.	7:30 AM EST on August 5, 2005

Animated Google Earth Movie of Nocturnal Low Level Jet Transport

All of the observations recorded for the NLLJ case on August 4-5, 2005
are also incorporated in an animated movie created by MDE.  Additional
details are provided along with animated versions of the RADAR wind
profiles.  The animated movie was created using Google Earth
Professional Version and was recorded and burned to DVD.  Appendix G-3
contains the DVD.  

Climatology of the NLLJ in Maryland

A lengthier investigation of the NLLJ over Maryland for multiple years
has been compiled in two separate reports.  Appendix G-4 contains
“Radar Wind Profiler Observations in Maryland:  A Preliminary
Climatology of the Low Level Jet” written by the University of
Maryland and Appendix G-5 contains “The Low Level Jet in Maryland: 
Profiler Observations and Preliminary Climatology” written by
Pennsylvania State University. 

Apportionment of Ozone Transport

The prior sections on Westerly Transport and the NLLJ provide case
studies of important transport mechanisms.  MDE has funded several
projects to take a closer look into the apportionment of ozone transport
culpability, to investigate how much ozone is transported by the
mechanisms and to discover from what states or regions the transported
ozone and ozone precursors originate.  There is strong evidence from
statistical analysis, modeling, and observations that points towards
heavy contributions of westerly transport and nocturnal low-level jet
transport to the 8-hour ozone non-attainment status in Baltimore
non-attainment area, which is often the upwind source for Cecil County. 


Cumulative evidence suggests 60-80% of the 8-hour ozone non-attainment
in the Baltimore corridor is due to westerly transport.  A statistical
analysis of ozone trends by meteorological regime (Appendix G-6),
estimates that 40-64% of the 8-hour ozone concentrations at Baltimore
can be attributed to regional effects rather than localized effects that
influence only the Baltimore area.  EPA modeling found that upwind
contributions are responsible for up to 68% of the non-attainment
problem in the BNAA.  UMD completed a cluster analysis of hundreds of
aircraft profile spirals that found when the greatest cluster trajectory
density lay over the Ohio River Valley (~59% of the profiles), transport
accounted for 69–82% of the afternoon boundary layer ozone.  Under
stagnant conditions (~27% of the profiles), transport still accounted
for 58% of the afternoon boundary layer ozone.  

Cumulative evidence also suggests the nocturnal low level jet plays a
role in the 8-hour ozone non-attainment status for the BNAA. 
Statistical analysis reports the presence of LLJs in Baltimore results
in a 7ppb increase in ozone concentrations and a 5ppb increase in
Washington DC (Appendix G-6).  A climatological study of RADAR
observations, shows that for the period of August, 1998 to November,
2002, NLLJs occurred on 70% of Code Orange 8-Hour Ozone days and 42% of
Code Red 8-Hour Ozone days (Appendix G-5).  

Using 232 aircraft vertical profiles performed in the Mid-Atlantic and
Northeast U.S. between 1997 and 2003, greater NOx emissions along back
trajectories from the aircraft profiles were positively correlated with
greater ozone mixing.  Ozone column contents during the flights were
strongly influenced by point source emissions with a slope of 61.6 ppb
ozone / (g NOx m-2 day-1) and a correlation (R2) of 0.997 (Appendix
G-1).  This shows that if upwind point source emissions are reduced,
ozone in Maryland will also be reduced at the same rate.  

A study of the relative contribution of transported and local
photochemistry to the ozone data for six exceedance days in August 2002
shows that if local photochemistry were the only source of ozone, none
of the 6 days examined would have exceeded the 8-hour ozone standard
(Appendix G-7).  The effect of the transported ozone is to add ozone
early in the day and hence to expand the time interval over which the
ozone levels may exceed 85 ppbv.  All indications point to the
importance of transported upwind point source emissions on the air
quality of Maryland.  Clearly transport is a paramount consideration,
which must be account for in an attainment plan especially in modeled
simulations. 

11.3  Modeled and Probable Range Attainment Demonstration

Instead of emphasizing a single design value from a single modeling
simulation as the core of an attainment demonstration, the preponderance
of atmospheric science knowledge shows intelligent use of models should
consider all of the model uncertainties and biases, include multiple
simulations, and ultimately produce, not a single design value, but a
range of predicted future design values.  This ensemble approach is
analogous to how a meteorologist determines a precipitation forecast. 
The meteorologist looks at multiple meteorological models, considers
uncertainties and biases of each model, reviews circumstances the model
may not account for, determines if there are any other outside
extenuating factors, and finally ascertains a range of possible
outcomes.  This range is then delivered to the forecast audience. 
Similarly, the MDE ensemble approach to weight of evidence modeling
provides a comprehensive evaluation of model performance for various
scales of time, area, height, and chemistry.  Based on the sensitivity
of the model under the evaluation schemes, a range of predicted 2009
8-hour ozone design values is forecasted for every monitoring site in
the Philadelphia non-attainment area.  The net result of applying
techniques of data analysis, observations, and modeling in the weight of
evidence is a favorable indication for successfully attaining the 8-hour
ozone NAAQS in 2009 for the area presently classified as the
Philadelphia non-attainment area.  This section provides a rigourous
scientific evaluation of the CMAQ performance, base case and future year
modeling, calculation of probable ranges, and alternative control
strategy modeling.

Evaluation of Model Abilities

An evaluation of model performance is performed using comparisons to
aircraft observations.  This analysis is important in understanding the
limitations of CMAQ and its strengths and weaknesses in simulating air
quality over the Mid-Atlantic in particular and the Ozone Transport
Region in general.  Appendix G-8 contains the full evaluation of CMAQ
against observations.  

Evaluation using Observations

In an effort to assess the ability of the Community Multi-scale Air
Quality model (CMAQ) to replicate ozone patterns, particularly high
ozone events over the Ozone Transport Region (OTR), comparisons are
performed between surface and aircraft ozone measurements and CMAQ ozone
simulations using the 2002 base case B1 emissions inventory.  Overall,
CMAQ does an excellent job of capturing the mean distribution of surface
layer ozone during the ozone season. However, the success is somewhat
misleading.  EPA performance criteria may appear to be independent or
offer different information, but in reality, nearly all criteria are
strongly geared toward average performance at the surface.  This
analysis explores several other means of evaluating the CMAQ model by
examining its performance only on high ozone days, by separating
performance at rural, suburban, and urban sites, and by comparing CMAQ
to aloft ozone data from aircraft campaigns.  The mixed results of these
comparisons show that CMAQ has critical shortcomings (e.g., transport
appears to be underrepresented) that appear to be magnified during
periods when high ground level ozone concentrations are a concern.

Comparison with aircraft profiles from 136 Regional Atmospheric
Measurement Modeling and Prediction Program (RAMMPP) flights reveals
that CMAQ has an overall high bias of ~15% from the surface to ~500
meters above sea level (ASL) and a low bias aloft (600-2600 meters ASL)
of ~10%.  Agreement between CMAQ-calculated and aircraft-measured ozone
varies substantially from flight to flight.  CMAQ, in general,
replicates the spatial pattern of high ozone events but often does not
capture the full spatial extent or magnitude of the high ozone patterns.
 Mean CMAQ-calculated and measured 8-hour ozone values from 66 surface
ozone monitors in the Baltimore, Washington, D.C., and Philadelphia
non-attainment areas are highly correlated (correlation coefficient, R,
of 0.92) over the ozone season (May 15 – September 15) and well
correlated (R=0.81) when a subset of 38 high ozone days (i.e. days when
the peak daily 8-hour average ozone in Maryland exceeded 85 ppb) are
compared.  Biases between CMAQ-calculated and observed 8-hour ozone
mixing ratios are minimal (-1.6 ppb) when averaged over the entire ozone
season.  However, larger negative biases are seen during high ozone days
(-2.2 ppb at urban sites and -7.7 ppb at rural/suburban sites).  

The high bias near the surface and low bias aloft is indicative of an
underestimation of ozone transport by CMAQ.  Aloft is where most
transport occurs; ground-level air does not move as readily.  On the
highest ozone days, CMAQ’s performance is not as good as on lower
ozone days.  This is a statistical reflection of CMAQ’s inability to
capture large-scale deviations from average or median conditions.  These
deviations occur on days with poor air quality.  CMAQ performs better at
urban sites than at suburban and rural areas.  This bias provides more
evidence that CMAQ is missing incoming ozone, possibly transport.  In
some instances, these rural/suburban areas are dominated by power-plant
emissions more than they are dominated by motor vehicle emissions. The
bias may also indicate that CMAQ’s relatively coarse vertical
resolution is unable to resolve the transport of point source (i.e.
power plant) emissions.  In particular, performance at upwind sites with
fewer nearby sources is poorer on the whole than it is at other sites
(see Appendix G-9).  

None of these shortcomings are reflected in EPA’s traditional ozone
model performance measures.  However, these shortcomings make it
necessary to consider CMAQ output and other evidence when evaluating the
probability of success of State Implementation Plans (SIPs).  EPA model
performance criteria reveals that CMAQ does a good job of capturing
temporal fluctuations in 8-hour ozone over the ozone season.  However,
excellent performance in predicting domain-wide ozone averages does not
mean CMAQ will predict extreme ozone, ozone changes, or the dynamic
range of ozone concentrations at particular locations with similar
accuracy.   In this analysis, we show that CMAQ-calculated ozone
concentrations have systematic biases.  These biases must be considered
when using CMAQ for predicting ozone changes at particularly poor air
quality sites for the purpose of demonstrating future attainment status
with respect to the 8-hour ozone NAAQS.   

Biases between CMAQ-calculated and measured 8-hour ozone concentrations
are minimal (1-2 ppbv) when averaged over the summer but larger (7-8
ppbv) on days when air quality is poor.   The inability of CMAQ to
capture the dynamic range of ozone concentrations is evidence that CMAQ
under responds to changes in meteorology and/or emissions.  Further
examples of the under responsive nature of CMAQ and the resulting
implications for SIP modeling are discussed in Appendix G-9.  Aircraft
observations show that CMAQ underestimates transport and has
compensating errors that overestimate the significance of local sources.
 This suggests that regional control programs should be more effective
than predicted by CMAQ and local programs somewhat less effective. 
Since the bulk of the control programs are regional (e.g. fleet
turnover, heavy duty diesels, and the Clean Air Interstate Rule),
greater changes in surface ozone can be expected than those predicted by
CMAQ, especially given CMAQ’s lack of response to change (see Appendix
G-9).

CMAQ exhibits its best performance in urban areas (small bias), less
success in suburban areas (underestimates ozone, a larger negative
bias), and its worst performance in rural areas (underestimates ozone
more, larger negative bias).  Since ozone must pass through rural areas
to get to urban areas, CMAQ is likely underestimating transport. 
CMAQ’s performance in capturing surface ozone is worst in the Ohio
River Valley and in central and southern Virginia, which are known to be
source regions for Maryland during high ozone episodes.  This relatively
poor performance adds uncertainty to estimates of transport into the
Mid-Atlantic region that are already likely biased low.

A detailed examination of Maryland ozone reveals that Maryland ozone
values improved significantly after the implementation of the NOx SIP
Call.  Ozone values were binned according to peak temperature to remove
most of the effects of meteorology from the analysis, revealing a
consistent 12% downward trend in ozone after the NOx SIP Call.

In regards to the demonstration of attainment, Maryland should be in
better, perhaps far better shape, than CMAQ predicts (see Appendix G-9).
 Demonstrated uncertainties and biases in CMAQ’s performance,
particularly with respect to extreme values and transport, imply that
CMAQ predicted future ozone concentrations are overestimated for the
Baltimore, Washington DC, and Philadelphia non-attainment areas.  Given
that CMAQ predicts a maximum 2009 8-hour ozone design value of 81 ppb at
the Fairhill monitor, this strongly suggests that Cecil County should be
firmly in attainment of the 8-hour ozone NAAQS in 2009.

Analysis of ozone trends before and after the NOx SIP Call reveals that
Maryland’s ozone concentrations improved significantly after the NOx
SIP Call.  This suggests that NOx controls, and especially power plant
controls are likely to be similarly effective in lowering ozone in the
future.  

The ozone concentrations in Virginia and the Ohio River Valley (known
source regions for Maryland) are under-predicted.  In addition, CMAQ’s
performance is at its worst in upwind, rural areas, and at its best in
downwind urban areas with a small positive bias.  As a result, the
significance of regional controls including fleet turnover, heavy-duty
diesel controls, and the NOx SIP Call are all probably underestimated. 
Conversely, the significance of local controls may be slightly
overestimated.  Finally, transport is likely underrepresented.

Figure 11.3.1 shows the median, 25th and 75th percentiles for all
aircraft-measured ozone (136 profiles) and matching CMAQ ozone
predictions for 2002.  While differences between the model-calculated
and observed profiles are substantial, the model-calculated profile
always remains between the 25th and 75th percentile of the observed
profile.  The data in Figure 11.3.1 suggests CMAQ has a high bias of ~15
% from the near surface to ~500 m above ground, and the aircraft
profiles have on average 10% more ozone than the CMAQ profiles aloft,
from 600 – 2600 m.    

 

Figure 11.3.1	Median CMAQ and aircraft O3 profiles from 2002
(June–August, 136 profiles).  The ends of the horizontal bars
represent the 25th and 75th percentiles.

A number of case studies are provided in Appendix G-8.  One such case
occurred on Tuesday, June 25, 2002 beginning at 10:00 AM EST.

 

Figure 11.3.2	Tuesday, June 25, 2002, 10:00 AM EST, Winchester, VA. Case
Study

		A.  24-hour HYSPLIT back trajectories terminating over Winchester, VA.

	Blue = 500m, Green = 1000m, Red = 1500m 

	B.  Aircraft (pink stars) and CMAQ (blue diamonds) ozone profiles.

	C.  OTR surface ozone monitor data.

	D.  2002 base B1 CMAQ simulation averaged for OTR monitor locations.

	E.  Difference plot.  Negative values indicate model under-prediction.

Based on surface comparisons from over that region, one conclusion is
that CMAQ is just missing the location of a local ozone plume (which the
aircraft interacts with briefly at ~700 m).  Thus, spatially, CMAQ
appears to be representing existing conditions with reasonable accuracy.
 However, because of the sharp ozone gradient over the measurement
location and resolution limitations of the model, CMAQ does not compare
favorably with aircraft observations.

Clustered and case study comparisons of modeled results versus
observations are not the only way to evaluate model performance.  A
thorough investigation also includes a review of the chemistry in CMAQ. 


Evaluation of Chemistry

In Appendix G-10, an analysis of photochemistry and nighttime reactions
identifies uncertainties in CMAQ and reasons it may underestimate the
benefit of NOx reductions.  This implies that Maryland may be more
likely to comply with the ozone standard than CMAQ indicates.  The CB4
mechanism and photochemical processor used in the version of CMAQ run
for this SIP (4.5.1) are simplified and missing reactions that were
thought to be inconsequential, but are now known or in some instances at
least suspected to play a major role in ozone production.  The
attainment demonstration CMAQ modeling can overestimate the rate of
formation and concentration of ozone, especially in VOC-rich urban
plumes.  The overall chemistry may be more NOx-limited than CMAQ would
suggest. Comparison of observations to the chemical processes simulated
in CMAQ shows that the model may still underestimate the importance of
photochemistry in large-scale, multi-day processes involving transport
and processing at higher altitudes, thus the simulations may
underestimate the benefit of decreasing NOx emissions, especially from
elevated sources such as power plants.

In order to accurately predict changes in ozone resulting from changes
in emissions, CMAQ must accurately represent the chemistry of the lower
atmosphere in both urban and rural locations and during both daytime and
nighttime conditions. Several studies suggest that CMAQ underestimates
the benefit from reduced emissions of NOx from elevated sources. 
Comparison of aircraft profiles to CMAQ-generated ozone profiles show
that CMAQ calculates too much ozone in the lowest few hundred meters and
too little between 600 and 2500 m altitude.  

The take away message from study presented in Appendix G-10 is that the
CB4 mechanism and photochemical processor used in the version of CMAQ
run for this SIP are simplified and missing reactions that were thought
to be inconsequential, but are now known or in some instances suspected
to play a major role.  All higher aldehydes are treated as acetaldehyde
(C2), but other higher aldehydes (such as C3 and C4) are certainly
formed and they react faster with NO3 radicals to form HNO3 at night,
representing an irreversible removal of NOx.  CB4 also neglects the
small fraction of alkanes that react directly with NO3 radicals to form
HNO3 at night, as well as a fraction of higher alkanes that rearrange to
form alkyl nitrates in daytime reactions with OH and NO.  Altogether,
these reactions probably sequester at least 1.5 ppb NOx, and unless
there are compensating errors, CMAQ may be overestimating the mixing
ratio of ozone formed in the Baltimore urban plume by about 6 ppb at the
surface.  Scattering of radiation by aerosols can accelerate ozone
formation in the lower free troposphere and inhibit it closer to the
Earth’s surface.  Model simulations of the impact of aerosols on jNO2
indicates that CMAQ should calculate 1-18 ppb less ozone in the lowest
few hundred meters and 1-3 ppb more ozone aloft - this moves the model
closer to aircraft observations, but not into agreement.  Indirect
evidence suggests that MM5/CMAQ is underestimating low level cloud
cover, and this could contribute substantially to the disagreement
between measurements and CMAQ. 

Maryland’s attainment demonstration CMAQ runs may well overestimate
the rate of formation and concentration of ozone, especially in VOC-rich
urban plumes.  The overall chemistry may be more NOx-limited than CMAQ
would suggest.  In comparison to aircraft observations, the base-case
CMAQ run underestimates the rate of photochemical smog production above
about 500 m and overestimates it below this altitude.  Comparison of the
details of the chemical processes simulated in CMAQ to observations
shows that CMAQ may still underestimate the importance of photochemistry
in large-scale, multi-day processes involving transport and processing
at higher altitudes, thus the simulations may underestimate the benefit
of decreasing NOx emissions, especially from elevated emissions sources
such as power plants.

Reasons for measurement/model differences may include problems with
emissions inventories, advection, vertical mixing, cloud cover, and
chemistry.  The NO2 photolysis rates that CMAQ uses, directly impacts
how much ozone is produced by CMAQ.  The rate coefficient for the
photolysis of NO2 (hereafter referred to as jNO2 value) used by the
default version of CMAQ assumes no aerosol loading.  In Figure 11.3.3,
aircraft profiles are compared against CMAQ values both with and without
aerosols.  Above 1000 m the revised CMAQ profiles (with revised jNO2
values, shown in green) are about 1 ppb larger than the standard CMAQ
profiles shown in blue.  Below 1000 m the standard CMAQ profiles are as
much as 18 ppb larger than the revised CMAQ profiles.





Figure 11.3.3	Ozone profiles from the aircraft (pink stars), CMAQ using
standard jNO2 values (without aerosols, and shown in blue open squares),
and CMAQ using revised jNO2 values (with aerosols, shown in green closed
squares) for July 17, 2002.

Aircraft profile flown over Louisa, VA 8:00 AM EST

B.  Aircraft profile flown over Richmond, VA 10:00 AM EST

C.  Aircraft profile flown over Crewe, VA 9:00 AM EST

Differences in CMAQ runs with and without revised photolysis rate
coefficients are seen in Figure 11.3.3 for model levels 1, 8, and 16
(approximately at the surface, 500 m, and 2000 m altitude) at 9:00 AM
EST when the largest differences occurred.  Values from the revised run
are subtracted from the standard run so that negative numbers mean the
standard CMAQ overestimated ozone (generally at low altitudes) and
positive numbers mean that the standard CMAQ underestimated ozone
(generally in the free troposphere). There are positive changes of 10
ppbv or more near the surface, representing overestimation by CMAQ, and
small negative changes (mean of 1 ppbv) above 500 m, indicating the
revised CMAQ run produces more ozone than the standard CMAQ, generally
in better agreement with observations.  . 

 

	Figure 11.3.3	Differences between standard and revised CMAQ ozone
(standard – revised).  The standard CMAQ used jNO2 values that did not
account for aerosols, while the revised CMAQ used jNO2 values that did
account for aerosols measured for a July 2002 smog and haze episode. 
These plots are for 9:00 EST at the surface (Panel A), 500m (Panel B),
and 3400m (Panel C) AGL.

Evaluation of Special Site Circumstances

An extenuating circumstance for the Collier’s Mill monitor, which is
the highest 8-hour ozone design value in the Philadelphia NAA, is the
geographic challenge of ventilating air pollutants in the face of a sea
breeze coming off of the ocean.  Field studies and numerical modeling
efforts around the country and internationally have shown that a sea
breeze circulation can influence local ozone concentrations.  A sea
breeze may exacerbate air pollution levels by constricting horizontal
and vertical ventilation.  Instead, the sea breeze re-circulates air
that would otherwise move off shore.  On other occasions, a sea breeze
may move relatively clean air onshore that will rapidly lower ozone
concentrations.  Understanding ozone formation and transport occurring
at the Collier’s Mill, New Jersey ozone monitor is important because
ozone levels at this location are likely enhanced by a “bay-breeze”
because of the proximity of the site to the Atlantic Ocean.  Appendix
G-11 provides an in depth look at the theoretical impact of the
Chesapeake Bay sea breeze on the Edgewood, Maryland ozone monitoring
site.  The same concepts apply at Collier’s Mill.  The impact of the
sea breeze is an important consideration because there is a real
possibility CMAQ could be making the planetary boundary layer too
shallow, forcing ventilation to calm conditions, which would effectively
create CMAQ over-predictions at Collier’s Mill.

Base Case and Future Year Modeling

This section presents a discussion of the basic attainment run for the
Philadelphia NAA with no adjustments to account for any issues CMAQ has
in predicting ozone changes.  This is the base case and future year
modeling.  By the conservative measure of this modeling, the Fairhill
monitor has the predicted 2009 design value of 81 ppb.  Based upon the
model evaluations and WOE presented throughout this chapter, this
strongly suggests that Cecil County should be firmly in attainment of
the 8-hour ozone standard in 2009 and all of Maryland will attain the
8-hour ozone standard by 2009.  The full modeling results are presented
in Chapter 12 and Appendix G-12.

Outputs from CMAQ were used to calculate ozone concentrations for a base
year (2002) and a future year (2009).  Multiple analyses and sensitivity
tests in this SIP (see Weight of Evidence Appendices, in particular)
show that CMAQ is less responsive than it should be to changes in
emissions.  Be that as it may, in this study the outputs from CMAQ were
evaluated with no consideration for any correction due to its
demonstrated lack of response.  Even by taking the outputs straight from
CMAQ, Cecil County should attain the 8-hour standard for ozone by 2010. 
All other Phildelphia NAA monitors are projected to have weight of
evidence ranges that attain 85 ppb.  As discussed in detail in Appendix
G-9 and G-12, CMAQ’s under-prediction of change means that Cecil
County area ozone is likely to be well below the 8-hour standard in
2010.  Also discussed in Appendix G-9 and G-12, by 2012, all monitors in
the Northeastern U.S. are predicted by CMAQ to be nearly in attainment. 
Given that CMAQ under-predicts changes in ozone, in 2012, the entire
Northeast and Mid-Atlantic should be well below the 8-hour standard for
ozone.  Chapter 12 provides more details on the preparation and
methodology employed in the base case and future year modeling.

CMAQ has traditionally been evaluated by using measures that reflect its
ability to represent average conditions instead of its ability to
respond to changes in emissions.  This represents a disconnect between
how the model is evaluated and how it is used.  It also means that CMAQ
was developed with its static performance in mind, not its dynamic
performance.  It is therefore likely that even though CMAQ meets
traditional performance measures such as mean error and bias, it will
under-predict the magnitude of ozone changes due to emissions changes. 
The probably range analysis in the next section quantifies some of the
uncertainties associated with CMAQ predictions and explains why future
year ozone will likely be lower than CMAQ predicts.

Probable Ranges

Several different methods have been used to compare the measured effects
from changes in emissions to those predicted by CMAQ, and all affirm the
idea that the reduction in ozone will be larger (e.g. ozone will be
better) than predicted by CMAQ.  For this reason, the weight of evidence
approach has been employed, resulting in the 2009 Probable Range of
design values at each site in the Baltimore NAA for 2009 (Figure
11.3.4).  Full details of the uncertainty in CMAQ and over-predictions
of future year ozone design values are provided in Appendix G-9.  

A study of the 2003 Northeast Blackout [Marufu et al., 2004] shows that
the blackout caused a drop of at least 7 ppbv ozone, and likely
considerably more, while a modeling study of the same event [Hu et al.,
2006] used CMAQ to predict only a 2.2 ppbv change.  An ongoing study by
EPA reveals that the NOx SIP call likely produced double the benefit
that CMAQ predicted.  Meanwhile, the State of New Jersey reports that
its ozone monitor locations appear to have reached their predicted 2009
design values in 2006, three years ahead of time.  When compared to
observations from the 2002 ozone season, CMAQ underpredicts diurnal
variability, and shows important performance uncertainties and biases in
areas just upwind of Maryland on high ozone days, namely the Ohio River
Valley and the state of Virginia.  Furthermore, performance on high
ozone days tends to be best in urban areas, next best in suburban areas,
and worst in rural areas, so CMAQ is under-predicting ozone in upwind
areas from which it would enter the largely urban and suburban
non-attainment areas.





Figure 11.3.4  2009 probable ranges for design values in Maryland.  The
lower end of each

 bar represents the lower bound of the most likely future year design
value,

 while the upper end of each bar represents an upper bound.

In this section uncertainties are estimated for two types of errors in
CMAQ modeling.  One source of uncertainty is the range of possible
meteorological conditions that might be encountered in future years. 
This is not to say that 2002 was not representative, but instead that
meteorological variability from year to year is well known, and any
future projections must account for this to achieve a reasonable margin
of safety, so particularly bad future year meteorology will not result
in numerous exceedances of the 8-hour ozone standard.  Some of the
uncertainty arising from the model and its emissions was estimated by
examining several different 2009 scenarios and determining the range of
possible 2009 ozone design values from those scenarios.  These two
sources of uncertainty do not cover all the possible sources of
uncertainty in CMAQ projections; errors in the inventory, meteorology,
and model formulation all play a role, but are significantly more
difficult to estimate.  The error estimate and the future year
meteorological variability estimate were combined to generate an
estimate of future year uncertainty in ozone design values.  

To account for CMAQ’s resistance to change, CMAQ changes were
increased by 50%, and probable future ozone design values were
calculated, along with probable ranges of ozone concentrations to
account for meteorological variability and some model errors.  The
resulting picture of future ozone is that likely 2009 ozone design
values correspond to 2012 design values calculated directly by CMAQ. 
This is in line with current observations from New Jersey (home to the
ozone monitoring location with the highest design value in the
Northeast) that show predicted 2009 ozone design values occurring in
2006.  Table 11.3.1 and Figure 11.3.5 show the full results of the
Weight of Evidence Probable Design Value Range approach.



Table 11.3.1

	2009 Observed, Modeled, and WOE design values for Cecil County,
Maryland.  Modeled and WOE results are provided for both 2009 and 2012.

Cecil County, Maryland 8-Hour Ozone WOE Attainment Demonstration

Site Name - County, State	Site ID Number	 	Observed	 	Modeled	 	WOE



 	2002 Base Year	 	2009 BOTW-B4	2012 BOTW-B4	 	2009 Probable	2009    
    Probable Range	2012 Probable	2012         Probable Range



 

 

	 





Fairhill - CECIL CO, MD	240150003	 	97.7	 	81	75	 	72.7	75.8	-	69.6
63.7	66.8	-	60.6



 

Figure 11.3.5	A graphical depiction of the data from Table 11.3.1,
depicting 2002 base year design values (blue columns), modeled 2009
design values (black diamonds), and the WOE probable future year design
values along with the upper and lower bounds for those future year
values (round circles and associated error bars, respectively).  All
Maryland monitoring locations are shown.  All sites are under the NAAQS
for 8-hour ozone.

The methodology and calculations employed to arrive at the WOE 2009 &
2012 Probable Design Value Ranges, shown in Table 11.3.1 and Figure
11.3.5 are outlined below:

------------------------------------------------------------------------
---------------------------------------------

Given:

The monitoring station at Fairhill, Maryland was used for the following
sample calculations.

	All values are 8-hour ozone design values (ppb)

	Observed 2002			= 97.7 ppb

	Modeled 2009 BOTW-B4 	= 81 ppb

	Modeled Benefit 			= Observed 2002 –Modeled 2009 BOTW-B4 

					= 97.7 ppb – 81 ppb = 16.7 ppb	

WOE Benefit = Modeled Benefit x 2

Allowing for considerable margin, the underestimation of the WOE Benefit
is conservatively cut in half (50%).  The conservative WOE Benefit is
calculated as follows:

WOE BenefitConservative = Modeled Benefit x 1.5 = 16.7 ppb x 1.5 = 25.05
ppb

WOE 2009 Probable	= Observed 2002 – WOE BenefitConservative 

				= 97.7 ppb – 25.05 ppb = 72.7 ppb

WOE 2009 Probable Range Calculations:

Upper Bound = Probable 2009 + 3.1 ppb = 72.7 ppb + 3.1 ppb = 75.8 ppb

Lower Bound = Probable 2009 – 3.1 ppb = 72.7 ppb – 3.1 ppb = 69.6
ppb

The 3.1 ppb adjustment to calculate the lower bound and upper bound
represents the uncertainty in future design values.  More detailed
information can be found in Appendix G-9.

WOE 2012 Probable Range Calculations:  Process is identical to the steps
described above, except for the substitution of Modeled 2012 BOTW-B4
instead of Modeled 2009 BOTW-B4.

------------------------------------------------------------------------
---------------------------------------------

Based on the WOE Design Value Probable Range, Fairhill is likely to be
in attainment of the 8-hour ozone standard in 2009 with a fair margin
for error.  CMAQ’s response to reductions in emissions is too rigid,
so CMAQ will underestimate the corresponding magnitude of ozone
reductions.  Even with CMAQ’s demonstrated uncertainties and biases,
when applied to attainment modeling exercises, CMAQ predicts Maryland
will attain the 8-hour ozone standard by 2012 and CMAQ predicts the
entire Northeast will attain the 8-hour ozone standard by 2018. 
Maryland has taken the extra step of modeling and performing WOE
probable design value range calculations for an additional suite of
alternative control strategies.

Alternative Control Strategies

Three alternative control strategies were employed for sensitivity
modeling and additional WOE probable design value range calculations: 
Programs for tree planting, telecommuting, and high electricity demand
days (HEDD).  The three strategies are all potential measures to be
taken in future years to make appreciable reductions in 8-hour ozone
design values.  

An urban tree canopy program is an important strategy because a
large-scale tree-planting program may offer a method to improve air
quality over the Philadelphia non-attainment area.  Additionally, a loss
of tree cover would harm air quality over the Philadelphia
non-attainment area.  Results from an analysis for Baltimore suggest
that decreases in ground level ozone concentrations on the order of 1-3
ppb could be realized with an increase in urban tree cover ranging from
20-40%.  Full results are provided in Appendix G-13.

The telecommuting sensitivity run is an effective, targeted approach. 
Ozone levels are episodic, and high ozone concentrations are largely
influenced by meteorology, so a forecast-driven program of emissions
reductions makes a lot of sense.  To this end, telecommuting is strongly
encouraged on high ozone days during the summer to take vehicles off of
the roads and vehicle emissions out of the air.  To simulate the effects
of an aggressive telecommute program, the University of Maryland modeled
the ozone reduction that would result if 40% of all light duty vehicles
were taken off the road in the non-attainment areas of Baltimore,
Philadelphia, and Washington, D.C. on 38 high ozone days during the
summer of 2002. Changes in mobile emissions were implemented as a flat
40% reduction in vehicle miles traveled in each county of the three
non-attainment areas.  The effects of implementing such a program were
modeled using version 4.4 of the CMAQ model.  CMAQ results showed that
across the three non-attainment areas modeled, an aggressive telecommute
program has the potential for considerable benefit to air quality with a
reduction in ozone of over 2 ppb.  Full results are provided in Appendix
G-14.

The high electricity demand day (HEDD) program is setup based on the
climatology of hot weather and the associated higher ozone
concentrations.  Ozone levels are driven during the summer months by a
combination of both pollutant emissions (i.e., NOx) and the
meteorological conditions (i.e., hot sunny days).  Another by product of
a hot summer day is an increase in peak electrical demand.  In order to
meet the spike in demand for electricity, additional electrical
generating units (EGUs) must be brought online by power companies. 
These types of EGUs typically do not have pollution control devices and
are therefore not necessarily clean.  This type of scenario results in
having the EGUs, which do not operate cleanly, operating on the hottest
summer days, which compounds the issue of poor air quality.  Since these
types of EGUs are only used sparsely during the year, they appear as
insignificant sources of pollutant emissions in the inventory and thus
their emissions have been over looked in the past.  However, now
reducing NOx on peak days is seen as an opportunity to provide a
significant ozone reduction benefit for Maryland and some other Ozone
Transport Commission (OTC) states.  With guidance from the OTC a
strategy is being formulated, which involves OTC staff, state
environmental and utility regulators, EPA staff, EGU owners and
operators and the independent system operators.  Maryland and some other
OTC States are committed to pursuing reductions in NOx emissions
associated with HEDD units on high electrical demand days during the
ozone season with such reductions to be achieved beginning in 2009 but
no later than 2012.  Additional modeling is planned using CMAQ to
calculate a range of benefit that would be associated with this type of
program.

In addition to the WOE probable design value range analysis performed
for the Philadelphia non-attainment area, the voluntary measures provide
supplementary evidence further exemplifying the probability that the
region will attain the 8-hour ozone standard assuming voluntary control
measures are put in place.  The “WOE With Voluntary Measures”
analysis was completed to examine how the model-predicted future year
8-hour ozone design values might be lowered and given as a range based
on voluntary controls which were not included in the full modeling
demonstration completed by the Ozone Transport Commission (OTC) modeling
centers for the Ozone Transport Region (OTR) states and is used in this
modeling demonstration as part of this State Implementation Plan.  The
potential benefits from voluntary programs (i.e., an aggressive
telecommuting program, the high electricity demand day (HEDD) program,
and even an aggressive tree canopy program) help demonstrate that all of
the region’s monitors are progressing towards attaining the 8-hour
ozone standard.  Table 11.3.2 shows the results of the WOE Design Values
With Voluntary Measures and additional details are provided in Appendix
G-15.  The analysis was completed to present supplemental evidence that
leads to the conclusion that MDE is confident that the Philadelphia
non-attainment area will attain the 8-hour ozone NAAQS standard by June
15, 2010.



Table 11.3.2

Design values for Cecil County, Maryland:  2009 Observed, Modeled, and
WOE-Without Voluntary Measures, and WOE-With Voluntary Measures. 
Modeled results and WOE-Without Voluntary Measures results are provided
for both 2009 and 2012.

Cecil County, Maryland 8-Hour Ozone NAA WOE Attainment Demonstration

	Site Name - County, State	Site ID Number	 	Observed	 	Modeled	 	WOE
- Without Voluntary Measures	 	Modeled	 	WOE - With Voluntary Measures



 	2002 Base Year	 	2009 BOTW-B4	2012 BOTW-B4	 	2009 Probable	2009    
    Probable Range	2012 Probable	2012         Probable Range	 	2009
Telecommute	 	2009 Probable	2009                Probable Range



 

 

	 



	 

 



Fairhill - CECIL CO, MD	240150003	 	97.7	 	81	75	 	72.7	75.8	-	69.6
63.7	66.8	-	60.6	 	78.1	 	70.7	73.8	-	67.6



12.0 Attainment Demonstration

The 8-hour Ozone Standard Attainment Demonstration analyzes the
potential of the Cecil County Maryland portion of the Philadelphia,
Wilmington, Atlantic City, PA-NJ-MD-DE non-attainment area (Philadelphia
NAA) to achieve attainment of the 8-hour ozone standard by June 15,
2010.  The attainment demonstration is comprised of the following
sections: Modeling Study Overview, Domain and Data Base Issues, Model
Performance Evaluation, Attainment Demonstration and Procedural
Requirements.

12.1  Modeling Study Overview

Background and Objectives

In 1997, the ozone National Ambient Air Quality Standard (NAAQS) was
reviewed, and the Environmental Protection Agency (EPA) recommended that
the ozone standard be changed from 0.12 parts per million (ppm) of ozone
measured over one hour to a standard of 0.08 ppb measured over eight
hours, with the average fourth highest concentration over a three-year
period determining whether or not an area is in compliance.  On June 15,
2005, EPA revoked the 1-hour ozone standard and re-designated the
Philadelphia NAA as a “Moderate” ozone NAA for the new 8-hour ozone
standard.  The new 8-hour ozone Philadelphia NAA was formed with
counties in the old 1-hour Philadelphia NAA and the additional four
counties of Sussex County (DE), Atlantic County (NJ), Cape May County
(NJ) and Ocean County (NJ).  Moderate ozone NAAs are required to
demonstrate attainment of the new 8-hour ozone standard using
photochemical modeling and Weight-of-Evidence analyses. Chapter 11
contains all the Weight-of-Evidence analyses supporting the Philadelphia
NAA attainment of the 8-hour ozone standard. 

The objective of the photochemical modeling study is to enable the
Maryland Department of the Environment (MDE) in coordination with the
Delaware Department of Natural Resources and Environmental Control (DE
DNREC), Pennsylvania Department of Environmental Protection (PA DEP),
the Philadelphia Air Management Services (Philadelphia AMS), and the New
Jersey Department of Environmental Protection (NJ DEP) to analyze the
efficacy of various control strategies, and to demonstrate that the
measures adopted as part of the State Implementation Plan (SIP) will
result in attainment of the 8-hour ozone standard by June 15, 2010. The
modeling exercise predicts future year 2009 air quality conditions based
on the worst episodes in the base year 2002, and applies control
measures to demonstrate the effectiveness of new control measures in
reducing air pollution. 

 

For the reason previously mentioned, the Ozone Transport Commission
(OTC) on behalf of the Ozone Transport Region (OTR) member states (of
which Maryland, Delaware, Pennsylvania and New Jersey are members)
undertook a photochemical modeling study to demonstrate compliance with
the 8-hour ozone NAAQS.  The 8-hour ozone attainment modeling study was
directed by the OTC Modeling Committee which consisted of the following
workgroups:  OTC Photochemical Workgroup, OTC Meteorological Modeling
Workgroup, OTC Emissions Inventory Development Workgroup, and the OTC
Control Strategy Workgroup.

The OTC Air Directors served on the OTC Oversight Committee and provided
oversight of the process.   

Table 12-1 identifies all jurisdictions within the 8-hour ozone
Philadelphia NAA.

Table 12-1 Jurisdictions Within the 8-Hour Ozone Philadelphia NAA

Jurisdiction	Counties	Classification	Attainment Date

Maryland	Cecil	Moderate	June 2010

Delaware	Kent

New Castle

Sussex1



Pennsylvania	Bucks

Chester

Delaware

Montgomery

Philadelphia



New Jersey	Atlantic1

Burlington

Camden

Cape May1

Cumberland

Gloucester

Mercer

Ocean1

Salem



Notes:

1 Counties added to the old 1-hour ozone Philadelphia NAA to comprise
the new 8-hour ozone Philadelphia NAA. 





Figure 12-1 provides a graphical representation of the 8-hour ozone
Philadelphia NAA.

Figure 12-1 8-Hour Ozone Philadelphia NAA

The photochemical model selected for the attainment modeling
demonstration was the EPA Models-3/Community Multi-scale Air Quality
(CMAQ) modeling system, which is a “One-Atmosphere” photochemical
grid model capable of addressing ozone at a regional scale and is
considered one of the preferred models for regulatory modeling
applications.  The modeling analyses set forth in this report have been
conducted in accordance with the Guidance on the Use of Models and Other
Analyses for Demonstrating Attainment of Air Quality Goals for Ozone,
PM2.5, and Regional Haze (Draft 3.2- September 2006).

Relationship to Regional Modeling Protocols

The states of Maryland, Delaware, Pennsylvania and New Jersey are all
members of the OTC and along with other member OTC states were able to
coordinate the modeling analyses performed for the Philadelphia NAA with
the regional modeling analysis conducted by the OTC Modeling Committee.

The lead agency for coordinating the running of the CMAQ model and
performing the modeling runs for the OTC was the New York State
Department of Environmental Conservation (NYSDEC).  Modeling centers for
the OTC included the NYSDEC, the University of Maryland at College Park
(UMD), and the Northeast States for Coordinated Air Use Management
(NESCAUM), the NJDEP and the Virginia Department of Environmental
Quality (VADEQ).  The lead modeling agency for coordinating the running
of the CMAQ model for the OTC and performing the modeling runs was the
NYSDEC, but member states of the OTC within the frame work of the OTC
managed the modeling project jointly.  All additional modeling for the
Philadelphia NAA was directed by MDE, DE DNREC, PA DEP, Philadelphia
AMS, and the NJ DEP and performed by NJ DEP and UMD under contract with
the MDE.

All OTC modeling inventories were developed, updated and shared among
the OTC states modeling centers and were provided by MARAMA.

Installation of the CMAQ model at all participating modeling centers was
completed and diagnostic procedures were run successfully.  The CMAQ
model has been benchmarked against other modeling platforms across the
OTR to ensure accurate results.

The OTC modeling committee oversaw the modeling effort and reported to
the OTC Oversight Committee through regular briefings and presentations,
and when needed offered additional information in cases where specific
technical decisions had policy implications.  MDE were members of the
various OTC committees to ensure that the Philadelphia NAA ozone
modeling protocol followed the same analyses being conducted by the OTC.
 Provided in Appendix H-1 is the Philadelphia NAA ozone modeling
protocol.

Conceptual Description

EPA recommends that a conceptual description of an area’s ozone
problem be developed prior to the initiation of any air quality modeling
study.  A “conceptual description” is a qualitative way of
characterizing the nature of an area’s non-attainment problem. Within
the conceptual description of a particular modeling exercise, it is
recommended that the specific meteorological parameters that influence
air quality be identified and qualitatively ranked in importance.

The conceptual description for this study was prepared by the NESCAUM
for use by the OTR member States.  The conceptual description document,
The Nature of the Ozone Air Quality Problem in the Ozone Transport
Region: A Conceptual Description (NESCAUM, October 2006), is provided in
Appendix H-2.  This document provides the conceptual description of the
ozone problem in the OTR states, consistent with the EPA’s guidance. 

 

 Domain and Data Base Issues

Episode Selection 

The procedures for selecting 8-hour ozone modeling episodes seek to
achieve a balance between the best possible science and regulatory needs
and constraints. Modeling episodes, once selected, influence technical
and policy decisions for many years. Clearly, both the direct and
implicit procedures used in selecting episodes warrant full
consideration.

The rationale for the selection of 2002 meteorology as input to the air
quality simulations includes a qualitative analysis (Ryan and Piety
2002) and a quantitative analysis (Environ 2005). These documents are
provided in Appendix H-3.

Recent research has shown that model performance evaluations and the
response to emissions controls need to consider modeling results over
long time periods, in particular full synoptic cycles or even full ozone
seasons. Based on this factor the entire ozone season was simulated for
the 2002 and 2009 State Implementation Plan (SIP) modeling runs (May 1
to September 30).  As a result, the total number of days examined for
the complete ozone season far exceeds EPA recommendations, and provides
for better assessment of the simulated pollutant fields. 

Size of the Modeling Domain 

In defining the modeling domain, one must consider the location of the
local urban area, the downwind extent of the elevated ozone levels, the
location of large emission sources, and the availability of
meteorological and air quality data.  The domain or spatial extent to be
modeled includes as its core the NAA.  Beyond this, the domain includes
enough of the surrounding area such that major upwind sources fall
within the domain and emissions produced in the NAA remain within the
domain throughout the day.

The boundaries of the OTC modeling domain are provided in Appendix H-4. 
This domain covers the Northeast region, including the northeastern,
central and southeastern US as well as Southeastern Canada.  The final
SIP modeling analysis utilized this modeling domain. 

Horizontal Grid Size 

The OTC platform provided the basic platform for the Philadelphia NAA
modeling analysis and utilized a coarse grid continental United States
(US) domain with a 36 km horizontal grid resolution.  The CMAQ domain is
nested in the MM5 domain.  A larger MM5 domain was selected for the MM5
simulations to provide a buffer of several grid cells around each
boundary of the CMAQ 36 km domain.  This was designed to eliminate any
errors in the meteorology from boundary effects in the MM5 simulation at
the interface of the MM5 model.  A 12 km inner domain was selected to
better characterize air quality in OTR and surrounding Regional Planning
Organization (RPO) regions. Appendix H-5 contains the horizontal grid
definitions for the MM5 and CMAQ modeling domains. 

Vertical Resolution

The vertical grid used in the CMAQ modeling was primarily defined by the
MM5 vertical structure.  The MM5 model employed a terrain following
coordinate system defined by pressure. The layer averaging scheme
adopted for CMAQ is designed to reduce the computational cost of the
CMAQ simulations.  Only the uppermost layers of the CMAQ domain were
coalesced.  All layers in the planetary boundary layer were left
undisturbed in moving from the MM5 to the CMAQ simulation.  This ensures
that the near-surface processes that affect air pollution the most are
faithfully represented in CMAQ, while the meteorological systems that
are driven by upper-level winds are allowed to develop properly in MM5. 
The effects of layer averaging have a relatively minor effect on the
model performance metrics when compared to ambient monitoring data.

Appendix H-6 contains the vertical layer definitions for the MM5 and
CMAQ modeling domains.  

Initial and Boundary Conditions

The objective of a photochemical grid model is to estimate the air
quality given a set of meteorological and emissions conditions. When
initializing a modeling simulation, the exact concentration fields are
not known in every grid cell for the start time.  Therefore, typically
photochemical grid models are started with clean conditions within the
domain and allowed to stabilize before the period of interest is
simulated. In practice this is accomplished by starting the model
several days, call spin-up time, prior to the period of interest.

The winds move pollutants into, out of, and within the domain. The model
handles the movement of pollutants within the domain and out of the
domain. An estimate of the concentration of pollutants at the edge of
the domain and therefore the quantity of pollutants moving into the
domain is needed. These are called boundary conditions.  The 12 km grid
boundary conditions were extracted from the 36 km CMAQ simulation. To
estimate the boundary conditions for the modeling study, boundary
conditions for the outer 36 km domain were derived every three hours
from an annual model run performed by researchers at Harvard University
using the GEOS-CHEM global chemical transport model (Moon and Byun 2004,
Baker 2005).  The influence of boundary conditions was minimized by
using a 15-day spin-up period, which is sufficient to establish
pollutant levels that are encountered in the Eastern U.S.  Additional
information on the extraction of boundary conditions is provided in
Appendix H-7. 

Meteorological Model Selection and Configuration

The Pennsylvania State University/National Center for Atmospheric
Research (PSU/NCAR) Mesoscale Meteorological Model (MM5) version 3.6 was
used to generate the annual 2002 meteorology for the OTC modeling
analysis.  The MM5 model is a non-hydrostatic, prognostic meteorological
model routinely used for urban- and regional-scale photochemical
regulatory modeling studies.   Professor Da-Lin Zhang (UMD) performed
the MM5 modeling in consultation with the NYSDEC and MDE staff.   

A more detailed description and performance evaluation of the MM5
modeling results are provided in Appendix H-8.  Based on model
validation and sensitivity testing, the MM5 configurations provided in
Appendix H-9 were selected.   

Emissions Model Selection and Configuration

The Sparse Matrix Operator Kernel Emissions (SMOKE) Emissions Processing
System was selected for the OTC modeling analysis.  SMOKE is principally
an emissions processing system and not a true emissions inventory
preparation system in which emissions estimates are simulated from
‘first principles’.  This means that, with the exception of mobile
and biogenic sources, its purpose is to provide an efficient, modern
tool for converting emissions inventory data into the formatted
emissions files required for a photochemical air quality model.

Inside the OTR, the emissions inventories prepared for the modeling
analyses were developed through a coordinated effort between the OTR
states and the Mid-Atlantic Northeast Visibility Union (MANE-VU)
Regional Planning Organization (RPO).  The 2002 emissions were first
generated by the individual OTR states.  These inventories were then
assembled and processed through the MANE-VU RPO.  The 2002 emissions for
non-OTR areas within the modeling domain were obtained from other RPOs
for their corresponding areas.  These RPOs included the Visibility
Improvement State and Tribal Association of the Southeast (VISTAS), the
Midwest Regional Planning Organization (MRPO) and the Central Regional
Air Planning Association (CENRAP).  These emissions were then processed
by the NYSDEC using the SMOKE (Version 2.1) processor to provide inputs
for the photochemical model. Wherever possible, the mobile source
emission inventories (in VMT format) were replaced with SCC-specific
county level emissions to more accurately reflect actual emissions for
typical ozone season day

The emissions inventories included a base case (2002), which serves as
the “parent” inventory off which all future year inventories (i.e.,
2009) are based.  The future year emissions inventories include
emissions growth due to projected increases in economic activity as well
as the emissions reductions due to the implementation of control
measures.

A detailed description of all SMOKE input files such as area, mobile,
fire, point and biogenic emissions files and the SMOKE model
configuration are provided in Appendix H-10. 

Air Quality Model Selection and Configuration

EPA’s Models-3/Community Multi-scale Air Quality (CMAQ) modeling
system was selected for the attainment demonstration primarily because
it is a “one-atmosphere” photochemical grid model capable of
addressing ozone on a regional scale and is considered one of the
preferred models for regulatory modeling applications.  The model is
also recommended by the Guidance on the Use of Models and Other Analyses
for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and
Regional Haze (Draft 3.2- September 2006).

The CMAQ configuration is provided in Appendix H-11.

Quality Assurance 

All air quality, emissions, and meteorological data were reviewed to
ensure completeness, accuracy, and consistency before proceeding with
modeling.  Any errors, missing data or inconsistencies, were addressed
using appropriate methods that are consistent with standard practices. 
All modeling was benchmarked through the duplication of a set of
standard modeling results across different modeling centers.

Quality Assurance (QA) activities were carried out for the various
emissions, meteorological, and photochemical modeling components of the
modeling study.  Emissions inventories obtained from the RPOs were
examined to check for errors in the emissions estimates. When such
errors were discovered, the problems in the input data files were
corrected, and the models were run again.

   

The MM5 meteorological model and CMAQ air quality model inputs and
outputs were plotted and examined to ensure sufficiently accurate
representation of the observed data in the model-ready fields, and
temporal and spatial consistency and reasonableness.  Both MM5 and CMAQ
underwent operational and scientific evaluations in order to facilitate
the quality assurance review of the meteorological and air quality
modeling procedures and are discussed in greater detail throughout this
document. Model Performance Evaluation

Overview

There are many aspects of model performance. This section will focus
primarily on the methods and techniques recommended by EPA for
evaluating the performance of the air quality model.  It should be noted
that other parts of the modeling process, the emissions and meteorology,
also undergo an evaluation.  It is with this knowledge and the desire to
keep the report concise, that the air quality model became the primary
focus of this section.

The first step in the modeling process is to verify the model’s
performance in terms of its ability to predict ozone in the right
locations and at the right levels. To do this, model predictions for the
base year simulation are compared to the ambient data observed in the
historical episode. This verification is a combination of statistical
and graphical evaluations. If the model appears to be predicting ozone
in the right locations for the right reasons, then the model can be used
as a predictive tool to evaluate various control strategies and their
effects on ozone. The purpose of the model performance evaluation is to
assess how accurately the model predicts ozone levels observed in the
historical episode and to use the knowledge of CMAQ’s performance to
put CMAQ’s predictions of future year air quality in the appropriate
context so that future policy decisions are informed by CMAQ’s
predictions and its performance.

The results of a model performance evaluation were examined prior to
using CMAQ’s results to support the attainment demonstration.  The
performance of CMAQ was evaluated using both operational and diagnostic
methods.  Operational evaluation refers to the model’s ability to
replicate observed concentrations of ozone and/or precursors (surface
and aloft), whereas diagnostic evaluation assesses the model’s
accuracy with respect to characterizing the sensitivity of ozone to
changes in emissions (i.e., relative response factors).

UMD performed an analysis to assess how well the CMAQ model simulated
the 2002 base case.  This analysis compared the 2002 CMAQ modeling
results with surface measurements and aloft ozone measurements obtained
from the UMD aircraft.  This analysis (Comparison of CMAQ Calculated
Ozone to Surface and Aloft Measurements) is provided in the
Weight-of-Evidence Chapter 11 of this document. 

The NYSDEC conducted a performance evaluation of the 2002 base case CMAQ
simulation (May 15-September 30) on behalf of the OTR member States. 
Appendix H-12 provides comprehensive operational and diagnostic
evaluation results, including spreadsheets containing the assumptions
made to compute statistics.  Highlights of this evaluation are provided
in the following sections.  

Diagnostic and Operational Evaluation

The issue of model performance goals for ozone is an area of ongoing
research and debate.  To evaluate model performance, EPA recommends that
several statistical metrics be calculated for air quality modeling.  Two
of the common metrics that are most often used to assess performance are
the mean normalized gross error and the mean normalized bias. The mean
normalized gross error parameter provides an overall assessment of model
performance and can be interpreted as precision, and the mean normalized
bias parameter measures a model's ability to reproduce observed spatial
and temporal patterns and can be interpreted as accuracy. EPA suggests
the following criteria: a mean normalized gross error (MNGE) of < 35%,
and a mean normalized bias (MNB) of < ±15% above a threshold of 40-60
ppb.  These results are presented in Table 12-2 for the Philadelphia NAA
and in Tables 12-3 and 12-4 on a monitor-by-monitor basis averaged over
all days for the 40 ppb and 60 ppb thresholds.  Figure 12-2 shows the
location of the monitors in the Philadelphia NAA.  

Table 12-2 Philadelphia NAA Statistics for 8-hour Ozone

Location	Ozone Cutoff Threshold

(ppb)	Mean Normalized Gross Error

(MNGE)

(%)	Mean Normalized Bias

(MNB)

(%)

Philadelphia NAA	40	12.94	-1.11

	60	11.90	-7.12



Table 12-3 Individual Site Statistics for 8-hour Ozone using 40 ppb
Cutoff

AIRS ID	Site Name	County	State	MNGE (%)	MNB

(%)

240150003	Fairhill	Cecil	MD	12.57	0.13

100031010	Brandywine Creek	New Castle	DE	11.57	-4.06

100031013	Bellefonte	New Castle	DE	12.27	4.47

100031007	Lums Pond	New Castle	DE	14.60	9.40

100010002	Killens Pond	Kent	DE	11.58	-2.12

100051003	Lewes 	Sussex	DE	11.61	-0.09

100051002	Seaford	Sussex	DE	12.77	-5.21

420170012	Bristol	Bucks	PA	12.65	-0.06

420450002	Chester	Delaware	PA	13.31	-4.83

420290050	West Chester	Chester	PA	12.36	-6.87

420290100	New Garden	Chester	PA	14.15	-9.27

420910013	Norristown	Montgomery	PA	11.98	1.36

421010136	Elmwood	Philadelphia	PA	13.93	8.49

421010004	Lab	Philadelphia	PA	25.00	22.89

421010014	Roxborough	Philadelphia	PA	13.91	-3.48

421010024	Northeast Airport	Philadelphia	PA	14.20	-8.42

340071001	Ancora	Camden	NJ	11.32	-3.60

340070003	Camden	Camden	NJ	12.20	-4.57

340150002	Clarksboro	Gloucester	NJ	12.27	-4.86

340110007	Millville	Cumberland	NJ	11.98	1.41

340010005	Nacote Creek	Atlantic	NJ	11.78	5.14

340290006	Colliers Mills	Ocean	NJ	13.31	-3.23

340210005	Rider	Mercer	NJ	12.79	-1.80



Table 12-4 Individual Site Statistics for 8-hr Ozone using 60 ppb Cutoff

  SHAPE  \* MERGEFORMAT    AIRS ID	Site Name	County	State	MNGE (%)	MNB

(%)

240150003	Fairhill	Cecil	MD	11.08	-6.58

100031010	Brandywine Creek	New Castle	DE	10.91	-9.07

100031013	Bellefonte	New Castle	DE	9.67	-0.21

100031007	Lums Pond	New Castle	DE	11.04	1.66

100010002	Killens Pond	Kent	DE	11.84	-9.47

100051003	Lewes 	Sussex	DE	10.92	-7.26

100051002	Seaford	Sussex	DE	13.88	-12.41

420170012	Bristol	Bucks	PA	11.85	-6.29

420450002	Chester	Delaware	PA	13.00	-9.07

420290050	West Chester	Chester	PA	12.72	-11.53

420290100	New Garden	Chester	PA	15.38	-14.26

420910013	Norristown	Montgomery	PA	9.26	-2.73

421010136	Elmwood	Philadelphia	PA	10.98	4.34

421010004	Lab	Philadelphia	PA	21.07	18.03

421010014	Roxborough	Philadelphia	PA	12.21	-5.86

421010024	Northeast Airport	Philadelphia	PA	14.85	-12.77

340071001	Ancora	Camden	NJ	10.55	-9.06

340070003	Camden	Camden	NJ	11.68	-6.82

340150002	Clarksboro	Gloucester	NJ	11.90	-8.84

340110007	Millville	Cumberland	NJ	10.66	-7.58

340010005	Nacote Creek	Atlantic	NJ	8.28	-1.42

340290006	Colliers Mills	Ocean	NJ	13.77	-11.57

340210005	Rider	Mercer	NJ	11.58	-8.37



Figure 12-2 Locations of Ozone Monitors in the Philadelphia NAA

The following statistics for the OTR domain have also been provided in
Appendix H-12.

Archive file containing 8-hour average observed and predicted ozone
organized by state.

Observed and predicted composite diurnal variations of selected species,
including but not limited to ozone at SLAMS/NAMS sites, ozone at CASTNet
and other sites, VOC species such as ethene, isoprene, formaldehyde and
gas phase compounds such as CO, NO and NO2. 

Statistical evaluation of daily maximum 8-hour ozone at SLAMS/NAMS sites
and CASTNet/other sites; statistics are computed using two different
thresholds for observed daily maximum ozone of 40 and 60 ppb. 
Statistics are computed by date (all sites on a given day) and by site
(one site over all days).

Statistical evaluation of daily maximum 8-hour ozone at SLAMS/NAMS sites
that fall within non-attainment counties; statistics are computed by
non-attainment area.

Statistical evaluation of daily average CO, NO, NO2, and SO2 at
SLAMS/NAMS and other sites; statistics are computed by date and by site.

Statistical evaluation of daily average ethene, isoprene, and
formaldehyde at SLAMS/NAMS and other sites; statistics are computed by
date and by site.

Plots of composite time series for daily max 8-hour ozone, root mean
square error and mean bias for illustrative purposes.  

Maps of daily 8-hour maximum predicted ozone across the modeling domain
compared with actual observations. 

Summary of Model Performance 

The CMAQ model was employed to simulate ozone for the 2002 season (May
through September).  A comparison of the temporal and spatial
distributions of ozone and its precursors was conducted for the study
domain, with additional focus placed on performance in the Philadelphia
NAA.  

The CMAQ model performance for surface ozone is quite good with low bias
and error.  Model performance is generally consistent from day to day. 
The results of the 2002 ozone season show that the modeling system tends
to over-predict minimum concentrations and slightly under-predict peak
concentrations.  The over-prediction of minimum concentrations is not of
great regulatory concern since attainment tests are based on the
application of relative response factors to daily peak concentrations. 
Prediction of minimum concentrations is still important to appropriately
model regional transport and nighttime ozone removal processes in order
to accurately estimate peak concentrations.  

The model performance for the Philadelphia NAA averaged over all
stations and all days meet the guidelines suggested by EPA.  Applying
those criteria to individual days is a much more stringent test that is
not required by EPA.  If those long-term average standards are applied
to daily performance, those criteria for acceptable model performance
are met on most individual days as well.

No significant differences in model performance for ozone and its
precursors were encountered across different areas of the OTR.  While
there are some differences in the spatial data among sub-regions, there
is nothing to suggest a tendency for the model to respond in a
systematically different manner between regions.  Examination of the
statistical metrics by sub-region confirms the absence of significant
performance problems arising in one area but not in another, building
confidence that the CMAQ modeling system is operating consistently
across the full OTR domain.

The evaluations discussed above show that the modeling system is doing a
good job of appropriately estimating 8-hour average surface ozone
throughout the OTR and in the Philadelphia NAA.  This confidence in the
modeling results allows the modeling system to be used to support the
development of emissions control scenarios and the State Implementation
Plan (SIP) to meet the 8-hour ozone NAAQS.  

As stated previously, the model performance for the 2002 ozone season
meets all EPA guidelines and thus demonstrates that the modeling
platform is appropriate for modeling emissions control scenarios for the
Philadelphia NAA 8-hr ozone SIP.  At the same time it must be remembered
that CMAQ has been evaluated by using measures that reflect its ability
to represent average conditions instead of its ability to respond to
changes in emissions.  Thus it is likely that although CMAQ has met the
traditional performance measures as stated in EPA guidance, it may in
fact under predict the magnitude of ozone changes due to various control
measures being modeled.  This means future year (i.e., 2009) modeling
results should be viewed not in the traditional sense as being exact,
but should be seen as an upper limit.  

Provided in the Weight-of-Evidence Chapter 11 (are sections on the
Comparison of CMAQ – Calculated Ozone to Surface and Aloft
Measurements, A Summary of the 2002 Base Case and 2009 Future Base Case
CMAQ Runs, Analysis of the Details of CMAQ 4.5 Chemistry, and
Uncertainty in CMAQ and Over Predictions of Future Year Ozone Design
Values) of this document is additional information on the uncertainty in
the CMAQ model and over predictions of future year ozone design values.

    Attainment Demonstration

Overview

The 8-hour ozone standard attainment demonstration analyzes the
potential of the Philadelphia NAA to achieve attainment of the 8-hour
ozone standard. The demonstration of achieving the 8-hour ozone standard
is based on both the CMAQ modeling results and a number of
Weight-of-Evidence analyses (provided in Chapter 11) that support the
attainment modeling results. Details of the CMAQ modeling are provided
in the following sections.

Modeling Attainment Test 

 

The modeled attainment test applied at each monitor was performed using
the following equation:

(DVF)I = (RRF)I (DVB)I

Where:

(DVB)I = the baseline concentration monitored at site I, in ppb

(RRF)I = the relative response factor, calculated near site I 

(DVF)I = the estimated future design value for the time attainment is
required, in ppb.

The future design value for each monitor in the Philadelphia NAA is
provided in Table 12-5 and in Figure 12-3.

	

Table 12-5 Modeling Attainment Test Using EPA Preferred Methodology

AIRS ID	Site Name	County	State	DVB	RRF	DVF

240150003	Fairhill	Cecil	MD	97.7	0.831	81  e1*f1 \# "#,##0"  

100031010	Brandywine Creek	New Castle	DE	92.7	0.875	81

100031013	Bellefonte	New Castle	DE	90.3	0.873	78

100031007	Lums Pond	New Castle	DE	94.5	0.843	79

100010002	Killens Pond	Kent	DE	88.3	0.891	78

100051003	Lewes 	Sussex	DE	87.0	0.893	77

100051002	Seaford	Sussex	DE	90.0	0.843	75

420170012	Bristol	Bucks	PA	99.0	0.896	88

420450002	Chester	Delaware	PA	91.7	0.885	81

420290050	West Chester	Chester	PA	95.0	0.868	82

420290100	New Garden	Chester	PA	94.7	0.835	79

420910013	Norristown	Montgomery	PA	92.3	0.883	81

421010136	Elmwood	Philadelphia	PA	83.0	0.905	75

421010004	Lab	Philadelphia	PA	71.3	0.906	64

421010014	Roxborough	Philadelphia	PA	90.7	0.911	82

421010024	Northeast Airport	Philadelphia	PA	96.7	0.901	87

340071001	Ancora	Camden	NJ	100.7	0.872	87

340070003	Camden	Camden	NJ	98.3	0.898	88

340150002	Clarksboro	Gloucester	NJ	98.3	0.898	88

340110007	Millville	Cumberland	NJ	95.7	0.847	81

340010005	Nacote Creek	Atlantic	NJ	89.0	0.874	77

340290006	Colliers Mills	Ocean	NJ	105.7	0.868	91

340210005	Rider	Mercer	NJ	97.0	0.889	86





Figure 12-3 Philadelphia NAA 8-Hour Ozone Base Year (2002) and          
                               Future Year (2009) Design Values

Current design values were calculated using the EPA approved method of
averaging the three design value periods that include the baseline
inventory year.  Specifically, the average design value was calculated
using the 2000-2002, 2001-2003, and 2002-2004 periods.

In the event that there were less than five years of available data at a
monitoring site the following procedure was used:

3 years of data - The current design value was based on a single design
value.  

4 years of data - The current design value was based on an average of
two design value periods. 

Less than 3 years of data – The site was not used in the attainment
test. 

A 3x3 array of grid cells surrounding each monitor was used in the
modeled attainment test as recommended by EPA for 12 km grid resolution
modeling to calculate RRFs. 

The predicted 8-hour daily maximum ozone concentrations from each
modeled day were used in the modeled attainment test, with the nearby
grid cell with the highest predicted 8-hour daily maximum ozone
concentration with baseline emissions for each day considered in the
test, and the grid cell with the highest predicted 8-hour daily maximum
ozone concentration with the future emissions for each day in the test. 


The RRFs used in the modeled attainment test were computed by taking the
ratio of the mean of the 8-hour daily maximum predictions in the future
to the mean of the 8-hour daily maximum predictions with baseline
emissions, over all relevant days, as defined below.  

The following rules were applied to determine the number of days and the
minimum threshold at each ozone monitor:

If there were 10 or more days with daily maximum 8-hour average modeled
ozone > 85 ppb an 85 ppb threshold was used.

If there were less than 10 days with daily maximum 8-hour average
modeled ozone > 85 ppb, the threshold was reduced in 1 ppb increments to
as low as 70 ppb, until there were 10 days in the mean RRF calculation.

If there were less than 10 days but more than 5 days with daily maximum
8-hour average modeled ozone > 70 ppb, then all days > 70 ppb were used.

No RRF calculations were performed for sites with less than 5 days > 70
ppb.

Provided in Appendix H-13 is additional information on the RRF and the
modeled attainment test.  

Unmonitored Area Analysis 

	 

An “unmonitored area analysis” using model adjusted spatial fields
was performed.  The basic steps of this process were as follows:

Interpolated ambient ozone design value data to create a set of spatial
fields.

Adjusted the spatial fields using gridded model output gradients (base
year values).

Applied gridded model RRFs to the model adjusted spatial fields.

Determined if any unmonitored areas are predicted to exceed the NAAQS in
the future.

Recommended EPA guidance was utilized in the “unmonitored area
analysis”.

Provided in Figure 12-4 is a map showing the spatially interpolated
extent of 8-hour ozone above the NAAQS in the Philadelphia NAA based on
a future case (2009) modeling simulation.

                                     

Figure 12-4 Spatially Interpolated Extent of the 8-Hour Ozone in the
Philadelphia NAA Using Predicted 2009 Design Values

In Figure 12-4 the clear areas within the Philadelphia NAA indicate the
areas that will be below the 8-hour NAAQS of 85 ppb.  Figure 12-4
clearly demonstrates that the Cecil County Maryland portion of the
Philadelphia NAA is predicted to be in attainment of the 8-hour ozone
NAAQS in 2009 as is a vast majority of the Philadelphia NAA.

Emissions Inventories 

For areas with an attainment date of no later than June 15, 2010, the
emission reductions need to be implemented no later than the beginning
of the 2009 ozone season. A determination of attainment will likely be
based on air quality monitoring data collected in 2007, 2008, and 2009.
Therefore, the year to project future emissions should be no later than
the last year of the three-year monitoring period; in this case 2009.

The 2002 base year emissions inventory were projected to 2009 using
standard emissions projection techniques discussed previously and in
Appendix 10.  The 2009 inventories developed by MANE-VU were used in the
attainment demonstration.  

Emission inventory guidance documents were followed for developing
future year inventories for point, area, mobile, and biogenic emissions.
 These procedures addressed projections of spatial, temporal, and
chemical composition change between the base year and projection year.

The OTC selected several control strategies for evaluation in the
attainment demonstration.  These were selected from groups of strategies
developed by the technical subcommittees responsible for identifying and
developing the regulations and/or control measures. 

Consideration was given to maintaining consistency with control measures
likely to be implemented in other RPOs.  Technology-based emission
reduction requirements mandated by the Clean Air Act were also included
in projecting future year emissions. 

Provided in Appendix H-14 is additional information on the emissions
used in future year modeling. 

Summary and Conclusions of Attainment Demonstration 

	 

The results of the future year (2009) modeling simulation indicate that
the maximum 8-hour ozone design value for the Maryland portion of the
Philadelphia NAA will be in the range of 81 ppb at the Fairhill, MD
Cecil County ozone monitor. This translates into an 8-hour ozone design
value reduction of approximately 17 ppb from 2002 to 2009.  

The same future year (2009) modeling simulation indicates that the
maximum 8-hour ozone design value for the entire Philadelphia NAA will
be in the range of 91 ppb at the Colliers Mills ozone monitor located in
Ocean County New Jersey.  This translates into an 8-hour ozone design
value reduction of approximately 15 ppb.  The significance of 91 ppb
range is that it falls just outside the Weight of Evidence range of 82
to 87 ppb.  According to EPA Guidance this means that the monitor might
be able to demonstrate attainment if there is enough sufficient
information in the form of a Weight-of-Evidence demonstration to
indicate that the future year (2009) design value will be less than the
8-hour ozone NAAQS.  

The Weight-of-Evidence demonstration (Chapter 11) presents numerous
analyses from monitoring trends to the CMAQ model’s inability to
precisely predict the effects of future year emissions reductions on
ambient concentrations of ozone.  All the analyses combined present
significant supplementary evidence to the future year (2009) modeling
that the Philadelphia NAA design value will be below the 8-hour ozone
NAAQS.

Presented in Figures 12-5, 12-6 and 12-7 are three maps of the
Philadelphia NAA 8-hour ozone design values for 2002 (the base year),
and the predicted 8-hour ozone design values for future years 2009 and
2102, respectively.  In each map of the Philadelphia NAA, clear areas
have 8-hour ozone design values below the NAAQS and the colored areas
have design values that are equal to or exceed the 8-hour ozone NAAQS. 
These three design value maps clearly demonstrate the trend of improved
air quality through 2012 and attainment of the 8-hour ozone NAAQS for a
majority of the Maryland/Delaware/Pennsylvania/New Jersey region.

Presented in Figure 12-8 are the 2002 8-hour ozone design values and the
predicted 8-hour ozone design values for future year 2012 for each ozone
monitor in the Philadelphia NAA.  These design values demonstrate that
the trend of improved air quality continues into 2012 and within the
range of attainment for the 8-hour ozone NAAQS.

Based on a combination of the future year (2009) modeling simulation
results and the rigorous Weight-of-Evidence (Chapter 11) analyses there
is over whelming evidence to demonstrate that the Philadelphia NAA will
attain the 8-hour ozone NAAQS by June 15, 2010.



                               

                              

Figure 12-5 Spatially Interpolated Extent of the 8-Hour Ozone Within the
Philadelphia NAA Using 2002 Base Year Design Values



                                 

Figure 12-6 Spatially Interpolated Extent of the 8-Hour Ozone Within the
Philadelphia NAA Using 2009 Predicted Future Year Design Values

							      

Figure 12-7 Spatially Interpolated Extent of the 8-Hour Ozone Within the
Philadelphia NAA Using 2012 Predicted Future Year Design Values

 

Figure 12-8 Philadelphia NAA 8-Hour Ozone Base Year (2002) and

Predicted Future Year (2012) Design Values

 Procedural Requirements

Reporting

Documents, technical memorandums, and data bases developed in this study
are available for distribution as appropriate.  This report contains the
essential methods and results of the conceptual model, episode
selection, modeling protocol, base case model development and
performance testing, future year and control strategy modeling, quality
assurance, weight of evidence analyses (Chapter 11), and calculation of
8-hr ozone attainment via EPA’s relative response factor (RRF)
methodology. 

Data Archival and Transfer of Modeling Files

All relevant data sets, model codes, scripts, and related software
required by any project participant necessary to corroborate the study
findings (e.g., performance evaluations, control strategy runs) will be
provided in an electronic format approved by the OTC Modeling Committee
within the framework of the OTC.  The OTC Modeling Committee has
archived all modeling data relevant to this project.  Transfer of data
may be facilitated through the combination of a project website and the
transfer of large databases via overnight mail.  Database transfers will
be accomplished using an ftp protocol for smaller datasets, and the use
of IDE and Firewire disk drives for larger data sets. 

	GENERAL REFERENCES

Ryan, W.F., Piety, C. (2002) Summary of 2002 Pollution Episodes in the
Mid-Atlantic.  The Pennsylvania State University Department of
Meteorology, State College, Pennsylvania and the University of Maryland
Department of Meteorology, College Park, Maryland.

Stoeckenius, T., Kemball-Cook, S. (2005) Ozone Episode Classification
Project for Ozone Transport Commission (Task 2b), ENVIRON International
Corporation, Novato, California.

Moo, N. and D. Byun (2004) A Simple User’s Guide For “geos2cmaq”
Code: Linking CMAQ with GEOS-CHEM.  Version 1.0.  Institute for
Multidimensional Air Quality Studies (IMAQS). University of Houston,
Houston, Texas.

Baker, K. (2005)   HYPERLINK
"http://www.ladco.org/tech/photo/present/ozone.pdf" 
http://www.ladco.org/tech/photo/present/ozone.pdf 

EPA GUIDANCE DOCUMENTS

Guidance on the Use of Models and Other Analyses for Demonstrating
Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze
(Draft 3.2- September 2006). U.S. Environmental Protection Agency,
Research Triangle Park, N.C.

 Sources and Health effects of Ground-Level Ozone, downloaded from  
HYPERLINK "http://www.dnr.state.wi.us/eq/aie/ozone/b_effect.htm" 
http://www.dnr.state.wi.us/eq/aie/ozone/b_effect.htm .

 Bell ML, Dominici F, and Samet JM. A Meta-Anaysis of Time-Series
Studies of Ozone and Mortality with Comparison to the National
Morbidity, Mortality, and Air Pollution Study. Epdidemiology 2005;
16:436 445.

 United States Environmental Protection Agecny. (17 July, 1997),
Factsheet: EPA’s Revised Ozone Standard. United State Environmental
Protection Agency, Technology Transfer Network, OAR Policy and Guidance.
Retrived on December 28, 2005 from the World Wide Web:   HYPERLINK
"http://www.epa.gov/ttn/oarpg/naaqsfin/03fact.html/" 
http://www.epa.gov/ttn/oarpg/naaqsfin/03fact.html/ 

 Ambient Air Pollution: Respiratory Hazards to Children Committee on
Environmental Health Pediatrics 1993 91: 1210-1213.

 Galizia, A. and Kinney, P.L. Long-Term Residence in Areas of High
Ozone: Associations with Respiratory Health in Nationalwide Sample of
Nonsmoking Young Adults. August 1999.  Environ Health Perspect, Vol.
107, No. 8, pp. 675-679

 Foinsbee et al., 1990; Horstman et al., 1990; McDonnell et al., 1991.
Out of Breath: A Report on the Health Consequences of Ozone and Acidic
Air Pollution in Metropolitan Chicago. American Lung Association of
Metropolitan Chicago, October 19, 1994

 United States Census Bureau. Census 2000 Demographic Profile
highlights: Maryland. (Online, follow link to Maryland). United Stated
Census Bureau, American FactFinder, 2000. Retrieved on March 28, 2005
from the World Wide Web:   HYPERLINK "http://factfinder.census.gov/" 
http://factfinder.census.gov/ 

 America Lung Association State of the Air, April 2006, pp. 1-207

 Final Rule to Implement the 8-Hour Ozone National Ambient Air Quality
Standard, Federal Register, Vol 70, No. 228, Nov.29, 2005, pp.
71612-71705.

 Small discrepancies may result due to rounding.

 EPA 40 CFR Parts 51, 52 & 90, Federal Register. Vol.70, No. 228, Nov.
29, 2005, pp.71612-71705.

 Growth factors based on Total Job Projections from the Maryland
Department of Planning, Planning Data Services, July 2004

 Growth factors based on BMC Final Round 6A Cooperative Forecasts.

 Growth factors based on VMT estimates provided by MDE Mobile Source
Division

 Federal Register/Vol. 71, No. 243/ Tuesday, December 19, 2006/ Proposed
Rules

 Small discrepancies may result due to rounding.

 Small discrepancies may result due to rounding.

 Final Rule to Implement the 8-Hour Ozone National Ambient Air Quality
Standard, Federal Register, Vol 70, No. 228, Nov.29, 2005, pp.
71612-71705.

 “Appendix A to Preamble—Methods to Account for Non-Creditable
Reductions When Calculating ROP Targets for the 2008 and Later ROP
Milestone Years,” in Final Rule to Implement the 8-Hour Ozone National
Ambient Air Quality Standard, Federal Register, Vol 70, No. 228, Nov.29,
2005,.

 If a region chooses to substitute reductions in NOx for reductions in
VOC, the substitution must be made in accordance with EPA’s NOx
Substitution Guidance. This guidance states the use of NOx emission
reductions must be consistent with the photochemical modeling used in
the region’s attainment demonstration. As photochemical attainment
modeling performed for the Metropolitan Baltimore region shows that NOx
reductions significantly reduce ozone formation, the region can
substitute NOx reductions for VOC reductions. Based on this modeling,
the Baltimore region can substitute NOx reductions for some or all
(0-15%) of the required VOC reductions for the 2008 reasonable further
progress (App. F – Severe SIP).

 The 1990 Phase II regulations specify 7.8 psi as the maximum RVP of
gasoline being sold in the Baltimore, DC-MD-VA ozone nonattainment area
in 1992.

 Ryan, W.F., “Local Ozone Forecasting and the NOx SIP Call Rule”,
EPA National Air Quality Conference, Orlando, FL, 2007.

Taubman, et al., "Airborne characterization of the chemical, optical,
and meteorological properties, and origins of a combined ozone-haze
episode over the Eastern United States", J. Atmos. Sci., 61, 1781-1793,
2004.

Taubman, et al., "Airborne characterization of the chemical, optical,
and meteorological properties, and origins of a combined ozone-haze
episode over the Eastern United States", J. Atmos. Sci., 61, 1781-1793,
2004. 

EPA, "Air Quality Modeling Technical Support Document for the NOx SIP
Call Appendix E", Office of Air and Radiation, Table E-29 ("Percent
contribution from upwind states to 8-hour non-attainment in Maryland"),
Sept 23, 1998.

Taubman, B.F., J.C. Hains, A.M. Thompson, L.T. Marufu, B.G. Doddridge,
J.W. Stehr, C.A. Piety, and R.R. Dickerson, "Aircraft vertical profiles
of trace gas and aerosol pollution over the mid-Atlantic United States:
Statistics and meteorological cluster analysis”, J. Geophys. Res.,
111, D10S07, 2006.

Page   PAGE  7 

Page   PAGE  141 

Page   PAGE  142 

Page   PAGE  169 

Should we articulate more of a canopy banking program? 

No mow legislation for DOT?

How?

Shari T. Wilson

Secretary

Robert M. Summers, Ph.D.

Deputy Secretary

Martin O'Malley

Governor

Anthony Brown

Lt. Governor

 

 

 

 

Philadelphia-Wilmington-Atlantic City, PA-DE-MD-NJ Non-Attainment Area

 

Philadelphia-Wilmington-Atlantic City, PA-DE-MD-NJ Non-Attainment Area

 

Ozone Monitor

Philadelphia-Wilmington-Atlantic City, PA-DE-MD-NJ Non-Attainment Area

2002 Base Year      DV

2009 DV

Design Values: Green (<82 ppb), Yellow (between 82 to 87 ppb), and Red
(> 88 ppb)

 

Philadelphia-Wilmington-Atlantic City, PA-DE-MD-NJ Non-Attainment Area

2002 Base Year Design Value

2012 Predicted DV

Design Values: Green (<82 ppb), Yellow (between 82 to 87 ppb), and Red
(> 88 ppb)

Panel E

Panel C

Panel A

Panel D

Panel B

CMAQ (with aerosols)

CMAQ (without aerosols) 

Aircraft

*

(Explanation: Due to 100% underestimation of the emissions reduction
benefits by CMAQ because of the model’s insensitivity to emissions
changes)

        

        Range of 2009 8-Hour Ozone Design Values from Weight of Evidence

All sites attain the 85ppb NAAQS for 8-Hour Ozone

All sites attain the 85ppb NAAQS for 8-Hour Ozone

        

        Range of 2009 8-Hour Ozone Design Values from Weight of Evidence

All sites attain the 85ppb NAAQS for 8-Hour Ozone

        

        Range of 2009 8-Hour Ozone Design Values from Weight of Evidence

