UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

	1650 Arch Street

	Philadelphia, Pennsylvania  19103

DATE:            November 3, 2011	

SUBJECT:	 Technical Support Document for Notice of Proposed Rulemaking
– Approval and                          Promulgation of Air Quality
Implementation Plans; Maryland; Baltimore                               
       Nonattainment Area Determinations of Attainment of the 1997
Annual Fine  

                         Particulate Standard

                         /s/

FROM:	Ruth Knapp, Environmental Protection Specialist 

Office of Air Program Planning  

TO:		File

                         /s/

THRU:	Cristina Fernandez 

		Director, Office of Air Program Planning  

A.  BACKGROUND

On July 18, 1997 (62 FR 36852), EPA established a health-based fine
particulate matter (PM2.5) National Ambient Air Quality Standard (NAAQS)
at 15.0 micrograms per cubic meter (µg/m3) based on a 3-year average of
annual mean PM2.5 concentrations, and a 24-hour standard of 65 µg/m3
based on a 3-year average of the 98th percentile of 24-hour
concentrations.  EPA established the standards based on significant
evidence and numerous health studies demonstrating that serious health
effects are associated with exposures to particulate matter.  The
process for designating areas following promulgation of a new or revised
NAAQS is contained in 107(d)(1) of the Clean Air Act (CAA).  EPA and
state air quality agencies initiated monitoring for the 1997 PM2.5 NAAQS
in 1999.  On January 5, 2005 (70 FR 944), EPA published its air quality
designations and classifications for the 1997 PM2.5 NAAQS based upon air
quality monitoring data from those monitors for calendar years
2001-2003.  These designations became effective on April 5, 2005.  The
Baltimore, Maryland area was designated nonattainment for the 1997
annual PM2.5 NAAQS (see 40 CFR Part 81.321).

B.  EPA REQUIREMENTS

PM2.5 Attainment Requirements 

These designations triggered the CAA’s requirements under 172(c),
which requires the submission of an attainment plan for each designated
nonattainment area.  EPA’s PM2.5 implementation rule, published on
April 25, 2007 (72 FR 20586) specifies that states must submit
attainment plans for their nonattainment areas to EPA by no later than
three years from the effective date of designation, that is, by April 5,
2008.  EPA’s PM2.5 implementation rule outlines the SIP requirements
for the attainment plan, which includes among other things, the
submission of an attainment demonstration showing the air quality
improvements expected to result from national and local control
measures, an analysis of reasonably available control measures (RACM),
including all reasonably available control technology (RACT), reasonable
further progress plan (RFP), and contingency measures.  EPA’s
implementation rule also sets the attainment date in these areas as
April 5, 2010, and the determination would be based on data from
2007-2009 (72 FR 20600).

The state of Maryland is subject to these requirements since several
counties are located in PM2.5 nonattainment areas.  The Baltimore fine
particulate matter (PM2.5) nonattainment area (hereafter referred to as
“the Baltimore Area” or “Area”) is composed of Anne Arundel
County, Baltimore County, Harford County, Howard County, and the City of
Baltimore.

Determinations of Attainment

Under EPA regulations at 40 CFR 50.7, the annual primary and secondary
PM2.5 standards are met when the annual arithmetic mean concentration,
as determined in accordance with 40 CFR  50, appendix N, is less than or
equal to 15.0 ug/m3.  Data handling conventions and computations
necessary for determining whether areas have met the PM2.5 NAAQS,
including requirements for data completeness, are listed in appendix N
of 40 CFR 50.  A year meets data completeness requirements when at least
75 percent of the scheduled sampling days for each quarter have valid
data.  The use of less than complete data is subject to the approval of
EPA, which may consider factors such as monitoring site closures/moves,
monitoring diligence, and nearby concentrations in determining whether
to use such data.  

If these proposed determinations of attainment are made final, the
requirements for Maryland to submit an attainment demonstration and
associated RACM, a RFP plan, contingency measures, and any other
planning SIPs related to attainment of the 1997 annual PM2.5 NAAQS
within the Baltimore Area would be suspended until such time as: a) the
Area is redesignated to attainment, at which time the requirements would
no longer apply; or, b) EPA determines that the Area has violated the
annual PM2.5 NAAQS, at which time, the Area would be required to submit
such plans.  See, 40 CFR 51.1004(c).  Additionally, EPA will have met
its statutory obligation pursuant to 179(c)(1) of the CAA to make a
determination based on the Area’s air quality data as of the
attainment date whether the Area attained the standard by that date.  

A determination of attainment does not shield an area from other
required actions such as New Source Review (NSR), conformity and
emission inventory requirements, and provisions to address pollution
transport, which would require emission reductions at sources or other
types of emission activities contributing significantly to nonattainment
in other areas or states, or interfering with maintenance in those
areas.

Determinations as to whether individual areas have attained the PM2.5
standards and thus qualify for the application of a determination of
attainment are being made in the context of rulemakings for individual
areas.  This Technical Support Document (TSD) provides an explanation of
EPA’s analysis used to determine whether the Baltimore Area has
attained the annual PM2.5 standard and whether it attained the standard
by the applicable attainment date.    

 

C.  MONITORING NETWORK 

The Baltimore Area currently has seven monitors which can be used for
comparison to the 1997 PM2.5 annual NAAQS.  The data from these monitors
is discussed below in section D.  One monitor located in the Area with
site ID 24-510-0040 does not meet the criteria (40 CFR 58 subpart D
58.30) to be used for comparison to the annual standard and is therefore
not included in this assessment. This area also has some collocated
monitors which also are not comparable to the annual standard, but their
data may be used to substitute for missing data at a primary monitor in
some situations (See, 40 CFR 50 appendix N).  Finally, the monitor with
site ID 24-510-0035 which was sometimes referred to as the FMC monitor
had to be shut down in August 2008 due to demolition occurring at the
monitoring site.  Based upon information provided by the Maryland
Department of the Environment (MDE), EPA agreed with MDE that the
remaining monitoring network adequately reflects air quality in the
Area.  The monitoring site that was demolished was not the site of the
maximum design value for the Area.  Additional technical support
explaining why data from this site is not needed to assess the
attainment status of this area can be found in two documents provided by
MDE to EPA.  See the attached e-mail correspondence to this TSD for this
information.    

D.  EPA’S ANALYSIS OF MONITORED DATA

 Monitoring Data 2008-2010 

In order to demonstrate that the Area is attaining the annual 1997 PM2.5
 NAAQS and has clean data for purposes of  40 CFR 51.1004(c), air
quality data from  EPA’s Air Quality System (AQS) from calendar years
2008-2010 was reviewed.  EPA’s determination that the Baltimore
nonattainment area attains the annual 1997 PM2.5 NAAQS is based upon
quality-assured, quality-controlled and state certified ambient air
monitoring data for the 2008–2010 period, as measured by Federal
Reference Method (FRM), Federal Equivalent Method (FEM), or Approved
Regional Method (ARM) monitors described in 40 CFR Part 50 Appendix N. 
The primary monitors used to determine the design value for the
Baltimore, MD nonattainment area are listed in Table 1.   The design
value (DV) for each monitor is the 3-year average of annual mean PM2.5
concentrations at the monitor, and is the value that would be compared
to the 1997 PM2.5 annual NAAQS.  The DV for the area is the highest
3-year average of the annual means measured at all the monitors in the
Area that meet the criteria to be used for comparison to the NAAQS.    

Table 1.  Baltimore Area 2008-2010 PM2.5 Data (in µg/m3)

 City	Site ID	2008 Annual Mean	2009 Annual Mean	2010 Annual Mean
2008-2010 Design Value 

Glen Burnie	24-003-1003	12.6	11.1	11.0	11.6

Padonia	24-005-1007	11.9	10.2	10.4	10.8

Essex	24-005-3001	12.6	11.0	11.6	11.7

Edgewood	24-025-1001	11.3	9.6	9.5	10.1

Baltimore	24-510-0006	12.2	10.1	10.1	10.8

Baltimore	24-510-0007	12.4	10.3	10.3	11.0

Baltimore	24-510-0008	12.7	11.1	11.0	11.6



According to AQS, monitoring site ID 24-003-0008 had some missing data
for one quarter of 2010.  However, data from a collocated monitor was
substituted for the missing data in accordance with 40 CFR 50 appendix N
(Interpretation of National Ambient Air Quality Standards For PM2.5). 
See, section 3.0 of the “Guideline on Data Handling Conventions for
the PM NAAQS”, EPA-454/R-99-008 (April 1999).   A copy of this
guideline is included as one of the attachments to this TSD along with
the AQS data report.  The values from the collocated monitor are
reflected in the annual 2010 mean value provided in AQS.     

The DV for the Baltimore Area for 2008-2010 is 11.7 ug/m3 and is below
15.0 ug/m3.  Therefore, the Area is attaining the annual PM2.5 NAAQS
based on the most recent complete, quality-assured and state certified
data available. 

Monitoring Data 2007-2009

In order to determine that the Baltimore Area attained the annual 1997
PM2.5 NAAQS by its attainment date of April 5, 2010, quality-assured,
quality-controlled and state certified ambient air monitoring data for
the 2007–2009 period, as measured by FRM, FEM, or ARM monitors
described in 40 CFR 50 appendix N was reviewed.   This data is in Table
2. 

Table 2.  Baltimore Area 2007-2009 PM2.5 Data (in µg/m3)

 City	Site ID	2007 Annual Mean	2008 Annual Mean	2009 Annual Mean
2007-2009 Design Value 

Glen Burnie	24-003-1003	13.4	12.6	11.1	12.4

Padonia	24-005-1007	13.3	11.9	10.2	11.8

Essex	24-005-3001	14.0	12.6	11.0	12.6

Edgewood	24-025-1001	12.2	11.3	9.6	11.0

Baltimore 	24-510-0035	14.1	*	*	*

Baltimore	24-510-0006	13.1	12.2	10.1	11.8

Baltimore	24-510-0007	13.4	12.4	10.3	12.0

Baltimore	24-510-0008	15.0	12.7	11.1	12.9

*Monitor Site ID 24-510-0035 shut down in August 2008 due to demolition
of the monitoring site.

Air Quality Data from site ID 24-003-1003 had some missing data for one
quarter in 2007.  In order to assess if this monitor attained the
standard, the maximum quarter substitution test as explained in the
“Guideline on Data Handling Conventions for the PM NAAQS”,
EPA-454/R-99-008 (April 1999) was applied. Basically, the test requires
replacing the missing data with the maximum concentration recorded at
the site during the same quarter over the 3-year period in question,
provided that the following criteria are met.  The site must have valid
data for at least 50 percent of the scheduled number of samples for each
quarter for all three years, and the emissions and meteorology for the
quarters to be substituted must be comparable to the emissions and
meteorology for the quarters in question.  Air quality data from site ID
24-003-1003 met the criteria and the site also attained the standard for
2007-2009 using this test.   

The DV for the Baltimore Area for 2007-2009 is 12.9 ug/m3 and is below
15.0 ug/m3.  Therefore, the Area attained the annual PM2.5 NAAQS by its
applicable attainment date based on quality- assured and state certified
data. 

Preliminary Monitoring Data for 2011

Preliminary data available to date for 2011 when considered in
conjunction with data from 2009 and 2010 indicates that the Baltimore
Area continues to attain the standard.   The 2011 data is not complete
and has not yet been quality-assured or certified but is provided below.
 

Table 3.  Baltimore Area Preliminary 2011 PM2.5 Data (in µg/m3) 

 City	Site ID	2011 Preliminary Annual Mean

Glen Burnie	24-003-1003	10.5

Padonia	24-005-1007	 9.9

Essex	24-005-3001	10.6

Edgewood	24-025-1001	 9.3

Baltimore	24-510-0006	 9.9

Baltimore	24-510-0007	 9.5

Baltimore	24-510-0008	10.8



 RECOMMENDED AGENCY ACTION

Based on quality-assured, quality-controlled, and state certified
ambient air monitoring data from 2008-2010 from the Baltimore Area, EPA
is making the determination that the Area attains the annual 1997 PM2.5
NAAQS.  Preliminary data from 2011 indicates that the Area continues to
attain the NAAQS.  Therefore, EPA is suspending the attainment-related
SIP requirements for the annual 1997 PM2.5 NAAQS pursuant to 40 CFR
51.1004(c).  Also, based on the quality-assured, quality-controlled, and
state certified ambient air monitoring data from 2007-2009 for the
Baltimore Area, EPA is making the determination that the Area attained
the annual 1997 PM2.5 standard by its attainment date of April 5, 2010. 


The following four attachments are included with this TSD:

EPA AQS Quick Look Report (AMP480) dated October 20, 2011 

Guideline on Data Handling Conventions for the PM NAAQS,
EPA-454/R-99-008 (April 1999)

E-mail Correspondence from MDE to EPA dated 8/14/2008 Notification of
Closing of FMC Site

E-mail Correspondence from MDE to EPA dated 8/18/2008 Network Analysis
of FMC Closure  

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