Technical Support Document (TSD) For 

Emissions Inventories for the Tioga Pennsylvania 

8 Hour Ozone Redesignation Request, Maintenance Plan, and,

State Implementation Plan (SIP) Base Year Inventory.

Submitted October 2006 by the Pennsylvania 

Department of Environmental Protection 

TSD Prepared December 2006 by

Alice H. Chow

Air Quality Analysis Branch, 3AP22

U.S. Environmental Protection Agency, Region 3

1650 Arch Street

Philadelphia, Pennsylvania 19103

/s/

____________________________________________

Reviewed by Walter Wilkie, Chief

Air Quality Analysis Branch (3AP22)

12/07/2006         

Date Signed

        

Introduction

The purpose of this document is to provide a technical summary of the
Air Quality Analysis Branch’s (AQAB) review of the emissions
inventories submitted with the Tioga Pennsylvania 8 Hour Ozone
Redesignation Request, Maintenance Plan and State Implementation Plan
(SIP) Base Year Inventory by the Pennsylvania Department of
Environmental Protection (PADEP).  This review does not determine the
approvability of the Redesignation Request or Maintenance Plan; but it
does determine the approvability of the SIP Base Year Inventory. 
Emissions inventories in a redesignation request are used to show
permanent and enforceable emission reductions between the year the area
was designated as a  nonattainment area and the year the area came into
attainment.  In a maintenance plan, the emissions inventories are used
to reflect the emissions during the time the area came into attainment
and are then projected to show that the area will remain in attainment. 
A SIP Base Year Inventory is the starting point from which other SIP
inventories are derived as well as serving as the benchmark for other
SIP planning activities, such as the establishment of an emissions
reduction credit program.  Tioga County was designated as an 8 hour
ozone nonattainment area with a Subpart 1 classification.  Subpart 1
area(s) are required to submit SIP base year inventories to EPA by June
15, 2007.  PADEP has included this early submission of SIP base year
with the redesignation request and maintenance plan package and has
requested EPA’s approval.

Any questions pertaining to this technical summary should be directed to
Walter K. Wilkie, Chief, Air Quality Analysis Branch, at 215-814-2150 or
via email at   HYPERLINK "mailto:wilkie.walter@epa.gov" 
wilkie.walter@epa.gov . 

II 	Emissions Inventories for Redesignation Request (Base Year
Inventory)

	In a redesignation request, emissions inventories are used to support
the States claim that the area has permanent and enforceable emissions
reductions.  In order to do this, the state should estimate the percent
reduction (from the year that was used to determine the design value for
designation and classification) achieved from federal and state control
measures; this is usually termed as the “base year” inventory. The
base year inventory contains VOC and NOx emissions for all source
categories, which includes point, area, onroad mobile, and nonroad
mobile for the ozone season.  

 

	In the Tioga redesignation request, the base year used was 2002.  The
Point Source data for 2002 is derived from the Pennsylvania Air
Information Management System (AIMS).  The AIMS database is comprised of
sources identified and inventoried by PADEP’s regional and central
offices through permitting, field inspections, and surveys.  Surveys are
conducted annually as facilities must submit emission estimates for
various operations, throughputs, work hours, as well as process data,
such as combustion unit data and fuel characteristics. For its
redesignation request, PADEP provided its 2002 actual summer weekday
emissions for NOx and VOC at the facility level and by Source
Classification Codes (SCCs).  “Summer weekday emissions” is defined
by PADEP as an average day’s emissions for a typical summer day during
the ozone season.  

	For the 2002 Nonpoint Source emissions, also known as “area
sources”, PADEP provided an inventory that contained estimations of
emissions by multiplying an emission factor by some known indicator or
activity level for each category at the county level.  These emissions
are typically calculated on an annual basis because the activity data
are generally only available on an annual basis.  PADEP further
converted these annual emissions to seasonal emissions, for ozone, the
summer season is defined as peak ozone season months of June, July, and
August.  Seasonal estimates were calculated using default monthly and
weekly profiles from EPA’s Emissions Modeling Clearing House (EMCH). 
Nonpoint source estimates were provided by SCC.

	The Nonroad Mobile Source 2002 inventory was prepared with EPA’s
NONROAD2005 model.  NONROAD estimates fuel consumption and emissions of
total hydrocarbons, carbon monoxide, nitrogen oxides, sulfur dioxide,
and particulate matter for all nonroad mobile source categories except
for aircraft, locomotives, and commercial marine vessels (CMV).  PADEP
provided emission estimates for locomotive engines and aircraft
emissions separately.  For locomotive engine emissions, PADEP projected
emissions from a 1999 survey using national fuel consumption information
and EPA emission and conversion factors.  For aircraft emissions, PADEP
estimated emissions using small airport operation statistics and
emission factors and operational characteristics in EPA’s Emissions
and Dispersion Modeling System (EDMS).  Nonroad mobile source emissions
were provided by SCC and classification.

	The Onroad Mobile Source 2002 emissions inventory was developed using
the most current version of EPA’s highway mobile source emissions
model MOBILE 6.2. PADEP also used PPSUITE, an enhanced version of the
Post Processor for Air Quality software systems used for previous
inventory and conformity submissions in Pennsylvania.  Traffic data
source and fleet data inputs were supplied by the 2002 PENNDOT Roadway
Management System.  PADEP provided Mobile6.2 input and output files for
review as a part of their redesignation request.  Mobile emissions
values were given in units of tons per summer day and were provided by
SCC.

AQAB staff reviewed the files and the emission results provided by PADEP
and found them to be reasonable for use in this redesignation request.

III.	Emissions Inventories for Maintenance Plan

2004 Attainment Year Inventory and Maintenance Plan Base Year Inventory

As stated earlier, emissions inventories are used to show emission
reductions for the area between the year of designation to nonattainment
and the year of attainment.  The inventory used for the year of
attainment is called the Attainment Year Inventory and also is referred
to as the Maintenance Plan Base Year Inventory.  This inventory is used
as the basis for the projected inventories that are used to show the
area will remain in attainment.  This section will discuss the 2004
Attainment Year Inventory that was used in the Tioga Redesignation
Request and Maintenance Plan submitted by PADEP.

PADEP compiled an actual 2004 Point Source inventory for the Tioga
Redesignation Request and Maintenance Plan.  The 2004 point source
inventory contained point source emissions derived from the Pennsylvania
Air Information Management System (AIMS).  As previously discussed, AIMS
houses all point source data compiled by various programs (permitting,
enforcement, etc.).  For its redesignation request, PADEP provided its
2004 actual summer weekday emissions for NOx and VOC at the facility
level and by Source Classification Codes (SCCs).  “Summer weekday
emissions” is defined by PADEP as an average day’s emissions for a
typical summer day during the ozone season.  

For the 2004 Nonpoint Source emissions, PADEP provided a projected
inventory from the 2002 inventory.  The factors used for the temporal
allocation of projections were provided by the Mid-Atlantic Regional Air
Management Association (MARAMA).  The factors were from EPA’s Sparse
Matrix Operator Kernel Emissions (SMOKE) v2.2 input files.  Data from
2004 area sources is a linear projection of between the 2002 base year
and the 2009 projected inventory.  Emissions were provided by SCC and
units were in tons per summer day.

	The 2004 emissions for Nonroad Mobile Source emissions were estimated
using the EPA NONROAD2005 model.  The NONROAD model estimates emissions
of total hydrocarbons, carbon monoxide, nitrogen oxides, sulfur dioxide,
and particulate matter for diesel, gasoline, liquefied petroleum
gasoline and compressed natural gas-fueled nonroad equipment categories.
 Aircraft and locomotives emissions were developed separately by PADEP. 
Just as with the 2002 nonroad inventory, for locomotive emissions in
2004, PADEP projected emissions from a 1999 survey using national fuel
consumption information and EPA emission and conversion factors.  For
aircraft emissions, PADEP estimated emissions using small airport
operation statistics and emission factors and operational
characteristics in EPA’s Emissions and Dispersion Modeling System
(EDMS).  Nonroad mobile source emissions were provided by SCC and
classification and were given in units of tons per summer day.

	The Onroad Mobile Source 2004 emissions inventory was developed using
the most current version of EPA’s highway mobile source emissions
model MOBILE 6.2.  In addition, PADEP uses a MOBILE pre- and post-
processing software package, PPSUITE, to process and compile
Pennsylvania’s highway data.  PPSUITE has been used in previous
inventory and conformity submittals from Pennsylvania.  Traffic data
source and fleet data inputs were supplied by the 2002 PENNDOT Roadway
Management System.  PADEP provided sample Mobile6.2 input and output
files for review.  Mobile emissions values were given in units of tons
per summer day and were provided by SCC.

AQAB staff reviewed the files and emission results and believes them to
be reasonable for use in the maintenance plan. 

2009 and 2018 Projection Emission Inventories

Projection inventories are used to show that the area will remain in
attainment.  Projection inventories for the years 2009 and 2018 were
used for the Tioga Maintenance Plan.  Inventories were developed for all
emission sources for both years.

PADEP used projection inventories for point and nonpoint sources
prepared by MACTEC Federal Programs, Inc., for the Mid-Atlantic Regional
Air Management Association (MARAMA).  MACTEC’s projected inventories
were from 2002, not 2004. PADEP’s 2004 inventory was not available at
the time of MACTEC’s work.

The Point Source projection inventories separated out the Electric
Generating Unit (EGU) and the non-EGU sector because different
projection methods were used for these two sectors.  For EGUs, EPA’s
Integrated Planning Model (IPM) was used to project future generation as
well as to calculate the impact of future control programs on future
emission levels.  For non EGUs, growth factors from EPA’s Economic
Growth and Analysis System, Version 5.0 (EGAS 5.0), the Department of
Energy’s Annual Energy Outlook 2005 fuel consumption forecasts and
state-supplied population, employment and other emission projection data
were applied to account for changes in economic activity.  Then, control
factors were applied to account for future emission reductions from
on-the-books (OTB) control regulations and on-the-way (OTW) control
regulations.

	The Nonpoint Source emissions for 2009 and 2018 were projected using
growth factors to account for population and economic activity.  Then,
as with point sources, control factors were used to account for future
emission reductions from on-the-books (OTB) control regulations and
on-the-way (OTW) control regulations. 

For the 2009 and 2018 Nonroad Mobile Source inventories, PADEP used
EPA’s NONROAD2005 model to generate these future inventories.  The
NONROAD model allows for the calculation of past year, present year, and
future year inventories (up to the year 2050) to be generated.  Growth
for locomotives came from the Association of American Railroads and
compared well with EGAS; and, small aircraft growth was estimated from
the Federal Aviation Administration’s APO Terminal Area Forecast
Detailed Report.

The 2009 and 2018 Onroad Mobile Source inventories were generated using
EPA’s MOBILE6.2.  In addition, PADEP used a PENNDOT study completed in
2005, “Statistical Evaluation of Projected Traffic Growth, Traffic
Growth Forecasting System:  Final Report, March 14, 2005” that
provided information used to forecast traffic volumes.  Growth rates for
vehicle miles traveled (VMT), and four functional road classifications
in each Pennsylvania county:  urban interstate, urban non-interstate,
rural interstate, and rural non-interstate were incorporated with
traffic data and socioeconomic forecasts which is inputted in PPSUITE to
calculate VMT and speeds; the output is then run in MOBILE6.2 to
calculate emissions.

AQAB staff reviewed the procedures, and found them to be reasonable for
development of these inventories.  

IV.	2002 SIP Base Year Inventory

	The base year inventory is the primary inventory from which other
inventories (3-year cycle inventories, reasonable further progress
inventories, modeling inventories) are derived.  The Clean Air Act calls
for State, local, and Tribal agencies to ensure that the base year
inventory is comprehensive, accurate, and current for all actual
emissions.  The base year inventory includes emissions estimates from
stationary point and nonpoint sources, onroad mobile sources, and
nonroad mobile sources.  For the 8-hour ozone NAAQS, the pollutants to
be inventoried are VOC, NOx and CO (carbon monoxide).  For the 8-hour
ozone NAAQS, VOC, NOx and CO emissions should be reported as actual
annual and actual summer weekday emissions (defined as an average
day’s emissions for a typical summer day during the ozone season). 
PADEP’s base year inventory is for 2002.  A significant amount of
documentation is required for these SIP base year estimates which PADEP
has provided.  

In the case of Tioga County, it was designated as an 8 hour ozone
nonattainment area with a Subpart 1 classification.  Subpart 1 area(s)
are required to submit SIP base year inventories to EPA by June 15,
2007.  PADEP elected to include this early submission of the SIP base
year with its redesignation request and maintenance plan package and has
requested EPA’s approval.

	PADEP’s methodologies concerning the generation of point, nonpoint,
onroad mobile and nonroad mobile emissions for the SIP base year are the
same as for the 2002 base year redesignation request.  However, EPA
guidance required, in addition to the NOx and VOC summer day emissions,
annual emissions for NOx and VOCs.  Further, the EPA guidance required
annual and summer day estimates for CO.  

	PADEP also applied rule effectiveness and rule penetration for its 2002
8-hour ozone SIP base year inventories.  Rule effectiveness reflects the
actual ability of a regulatory program to achieve the emission
reductions required by regulation (or perhaps voluntarily adopted).  In
the 2005, EPA developed recommendations to revise EPA’s existing rule
effectiveness guidance; due to the fact that PADEP’s inventory was
developed prior to the issuance of the new rule effectiveness policy,
EPA’s previous policy was followed, which assumed an 80% rule
effectiveness for applicable sources unless otherwise specified.  Rule
penetration is an estimate of percentage of emissions in a source
category that are emitted at facilities subject to the requirements of a
rule.  PADEP applied rule penetration for its nonpoint sources at 60%.

AQAB staff reviewed the results, procedures, and methodologies for the
SIP base year, and found them to be approvable.  The following table
summarizes PADEP’s 2002 SIP Base Year.

Tioga County, 2002 SIP Base Year













 	VOC Emissions	NOx Emissions	CO Emissions

Source Type	Tons/yr	Tons/day	Tons/yr	Tons/day	Tons/year	Tons/day

Point Sources	192	0.5	476	1.3	715	1.9

Nonpoint Sources 	1343	2.8	179	0.2	2835	3.76

Onroad Mobile Sources	1084	3.4	1795	5.4	16,487	45.2

Nonroad Mobile Sources	650	1.7	387	1.5	3711	11.8

TOTAL Emissions	3269	8.4	2836	8.4	23747	62.7



 “Emissions Inventory Guidance for Implementation of Ozone and
Particulate Matter National Ambient Air Quality Standards (NAAQS) and
Regional Haze Regulations” EPA-454/R-05-001, August 2005

