UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: October 24, 2011

SUBJECT: Technical Support Document - Pennsylvania; Attainment Plan for the 

Pennsylvania Portion of the Philadelphia-Wilmington, Pennsylvania-New JerseyDelaware 1997 Fine Particulate Matter Nonattainment Area

/s/

FROM: Rose Quinto, Environmental Engineer

Office of Air Program Planning

TO: File

/s/

THRU: Cristina Fernandez, Associate Director

Office of Air Program Planning

This document provides a technical review of a revision to the Pennsylvania State 

Implementation Plan (SIP) submitted by the Pennsylvania Department of the Environmental 

Protection (PADEP) on April 12, 2010. This SIP revision addresses the attainment plan of the 

1997 annual fine particulate matter (PM2.5) national ambient air quality standard (NAAQS) for 

the Pennsylvania portion of the Philadelphia-Wilmington, Pennsylvania-New Jersey-Delaware

(PA-NJ-DE) nonattainment area (Philadelphia area). The attainment plan includes Philadelphia

area’s attainment demonstration, motor vehicle emission budgets (MVEBs) used for 

transportation conformity purposes, an analysis of reasonably available control measures 

(RACM) and reasonably available control technology (RACT), base year emissions inventory, 

and contingency measures.

A. BACKGROUND

I. Designation History

On July 18, 1997 (62 FR 36852), the Environmental Protection Agency (EPA)

established the 1997 PM2.5 NAAQS, including an annual standard of 15.0 micrograms per cubic 

meter (g/m3) based on a 3-year average of annual mean PM2.5 concentrations and a 24-hour (or 

daily) standard of 65 g/m3based 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 PM2.5.

Following promulgation of a new or revised NAAQS, EPA is required by the Clean Air 

Act (CAA) to designate areas throughout the United States as attaining or not attaining the 
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NAAQS; this designation process is described in section 107(d)(1) of the CAA. In 1999, EPA 

and State Air Quality Agencies initiated the monitoring process for the 1997 PM2.5 NAAQS and 

by January 2001, established a complete set of air quality monitors. On January 5, 2005 (70 FR 

944), EPA promulgated initial air quality designations for the 1997 PM2.5 NAAQS based on air

quality monitoring data for calendar years 2001-2003.

On April 14, 2005 (70 FR 19844), EPA promulgated a supplemental rule amending the 

Agency’s initial designations, with the same effective date (April 15, 2005) as 70 FR 944. As a 

result of this supplemental rule, PM2.5 nonattainment designations are in effect for 39 areas, 

comprising 208 counties within 20 States (and the District of Columbia) nationwide, with a 

combined population of about 88 million. The Pennsylvania portion of the Philadelphia area is 

included in the list of areas not attaining the 1997 PM2.5 NAAQS. The Pennsylvania portion of 

the Philadelphia area consists of the following counties: Bucks, Chester, Delaware, 

Montgomery, and Philadelphia.

It should be noted that on November 13, 2009 (74 FR 58688), EPA revised the existing 

designation tables in 40 CFR part 81.339 to clarify that the 1997 designations were for both the 

annual PM2.5 NAAQS and the 24-hour PM2.5 NAAQS. The Pennsylvania portion of the 

Philadelphia area was designated unclassifiable/attainment for the 24-hour PM2.5 NAAQS.

II. Clean Air Fine Particle Implementation Rule

On April 25, 2007 (72 FR 20586), EPA issued the Clean Air Fine Particle 

Implementation Rule for the 1997 PM2.5 NAAQS. The “PM2.5 Implementation Rule” describes 

the CAA framework and requirements for developing SIPs for areas designated nonattainment 

for the 1997 PM2.5 NAAQS (attainment plans). An attainment plan must include a 

demonstration that a nonattainment area will meet the applicable NAAQS within the time 

provided in the statute. This demonstration must include modeling (40 CFR 51.1007) that is 

performed in accordance with EPA modeling guidance (EPA-454/B-07-002, April 2007). It

must also include supporting technical analyses and descriptions of all relevant adopted Federal, 

state, and local regulations and control measures that have been adopted in order to provide 

attainment by the proposed attainment date. 

For the 1997 PM2.5 NAAQS, an attainment plan must show that a nonattainment area will 

attain the 1997 PM2.5 NAAQS as expeditiously as practicable, but within five years of 

designation (i.e. attainment date of April 2010 based on air quality data for 2007-2009). If the 

area is not expected to meet the NAAQS by April 2010, a state may request to extent the 

attainment date by one to five years based on the severity of the nonattainment problem or the 

feasibility of implementing control measures (CAA section 172(a)(2)) in the specific area. For 

EPA to approve an extension of the attainment date beyond 2010, the state must provide an 

analysis to support the request and demonstrate that the attainment date is as expeditious as 

practicable for the area given the facts and circumstances of the area and consistent with the 
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statutory criteria for an extension.

For each nonattainment area, the state must demonstrate that it has adopted all RACM, 

including all RACT as needed to provide for attainment of the PM2.5 standards in the area “as 

expeditiously as practicable.” The PM2.5 Implementation Rule provides guidance for making 

these RACM and RACT determinations. Any measures that are necessary to meet these 

requirements which are not already either Federally promulgated or in an EPA-approved part of 

the SIP must be submitted as part of the state’s attainment plan. Any state measures must meet 

the applicable statutory and regulatory requirements, and in particular, must be Federally

enforceable.

The PM2.5 Implementation Rule also includes guidance on pollutants that states must 

address in their attainment demonstrations. Section 302(g) of the CAA authorizes EPA to 

regulate criteria pollutants and their precursors. In the case of PM2.5, the main chemical 

precursors are sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), and volatile organic 

compounds (VOCs). The effect of reducing emissions of precursor pollutants that contribute to

PM2.5 concentrations varies by area, however, depending on PM2.5 composition, emission levels, 

and other area-specific factors. For this reason, the PM2.5 Implementation Rule provided 

guidance recommending that states elect direct PM2.5 emissions and the precursor that would be 

most effective for attaining the NAAQS within the specific area, based upon an appropriate 

technical demonstration.

In accordance with the PM2.5 Implementation Rule, direct PM2.5 emissions means “solid 

particles emitted directly from an air emissions source or activity, or gaseous emissions or liquid 

droplets from an air emissions source or activity which condense to form particulate matter at 

ambient temperatures. Direct PM2.5 emissions include elemental carbon, directly emitted organic 

carbon, directly emitted sulfate, directly emitted nitrate, and other inorganic particles (including 

but not limited to crustal material, metals, and sea salt).”

The PM2.5 Implementation Rule requires all states to address SO2 as a PM2.5 attainment plan 

precursor and to evaluate SO2 for possible control measures in all PM2.5 nonattainment areas. States 

are also required to address NOX as a PM2.5 attainment plan precursor and evaluate reasonable 

controls for NOX in PM2.5 attainment plans, unless the state and EPA make a finding that NOX

emissions from sources in the state do not significantly contribute to PM2.5 concentrations in the 

relevant nonattainment area.

Although current scientific information shows that certain VOC emissions are precursors 

to the formation of secondary organic aerosol, and significant progress has been made in 

understanding the role of gaseous organic material in the formation of organic PM, this 

relationship remains complex. Further research and technical tools are needed to better 

characterize emissions inventories for specific VOC compounds and to determine the extent of 

the contribution of specific VOC compounds to organic PM mass. Because of these factors, the 

PM2.5 Implementation Rule did not require states to address VOCs as PM2.5 attainment plan 
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precursors and evaluate them for control measures, unless the State or EPA makes a finding that 

VOCs significantly contribute to a PM2.5 nonattainment problem in the state or to other 

downwind air quality concerns.

The PM2.5 Implementation Rule describes the formation of particles related to NH3

emissions, which is a complex, nonlinear process. Though recent studies have improved our 

understanding of the role of NH3 in aerosol formation, ongoing research is needed to better 

describe the relationships between NH3 emissions, particulate matter concentrations, and related 

impacts. Also, area specific data are needed to evaluate the effectiveness of reducing NH3 

emissions on reducing PM2.5 concentrations in different areas, and to determine where NH3

decreases may increase the acidity of particles and precipitation. For these reasons, in the PM2.5

Implementation Rule, NH3 is presumed not to be a PM2.5 attainment plan precursor, meaning that

the state is not required to address NH3 in its attainment plan or evaluate sources of NH3

emissions for reduction measures, unless the state or EPA makes a finding that NH3 significantly

contributes to a PM2.5 nonattainment problem in the area or to other downwind air quality

concerns.

The presumptive inclusion of NOX and the presumptive exclusion of VOC and NH3 as 

attainment plan precursors can be reversed based on an acceptable technical demonstration for a 

particular area by the state or EPA. Such a demonstration should include information from 

multiple sources, including results of speciation data analyses, air quality modeling studies, 

chemical tracer studies, emission inventories, or special intensive measurement studies to 

evaluate specific atmospheric chemistry in an area (See PM2.5 Implementation Rule for more 

information).

The PM2.5 Implementation Rule also provided guidance on other elements of a state’s 

attainment plan, including, but not limited to, consideration of emission inventories, contingency

measures, and MVEBs used for transportation conformity purposes.

There are, however, three aspects of the PM2.5 Implementation Rule for which EPA 

received petitions requesting reconsideration. These pertain to the presumption or advance 

determination that compliance with the requirements of the Clean Air Interstate Rule (CAIR) 

automatically satisfies the requirements for RACT or RACM for NOx or SO2 emissions from 

electric generating unit (EGU) sources participating in regional cap and trade programs; the 

suggestion in the preamble that the economic feasibility element of a RACT determination for 

EGUs should include consideration of whether the cost of a measure is reasonable in light of the 

benefits; and the policy described in the preamble of allowing certain emissions reductions from 

outside the nonattainment area to be credited as meeting the RFP requirement. EPA is granting 

these petitions and intends to undertake rulemaking to change these aspects of the PM2.5

Implementation Rule. The attainment plan for the Pennsylvania portion of the Philadelphia area

did not rely on any of these aspects of the rule.
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III. Attaining Data Determination and Finding of Attainment

The data in Table 1 indicates that the Pennsylvania portion of the Philadelphia area is 

meeting the 1997 annual PM2.5 NAAQS. In addition, Table 2 shows that the Philadelphia area 

continues to attain the 1997 annual PM2.5 NAAQS by 2010. More detailed information can be 

found in a technical support document (TSD), entitled “Technical Support Document for the 

Modeling Portion of the Commonwealth of Pennsylvania’s Fine Particulate Matter State 

Implementation Plan,” dated October 11, 2011, available on line at www.regulations.gov, Docket 

No. EPA-R03-OAR-2010-0391. However, this action does not determine that the Pennsylvania 

portion of the Philadelphia area has attained the 1997 annual PM2.5 NAAQS and the information 

is included here only to support the Pennsylvania’s demonstration that the Pennsylvania portion 

of the Philadelphia area could meet the attainment date of April 5, 2010, and continues to attain 

based on the most recent data available. EPA plans to take action to formally determine the 

Pennsylvania portion of the Philadelphia area’s attainment of the 1997 annual PM2.5 NAAQS in a 

separate action.

Table 1. 2009 Annual Averaged PM2.5 Design Value

County Site Name Site Number Design Value (μg/m3)

Bucks Bristol 420170012 12.1

Chester New Garden 420290100 12.4

Delaware Chester 420450002 13.3

Montgomery Norristown 420910013 11.3

Philadelphia AMS Lab 421010004 12.9

Philadelphia NE Airport 421010024 11.9

Philadelphia Broad Street 421010047 13.5

Philadelphia Elmwood 421010136 12.7

Table 2. 2008-2010 Monitored Annual Design Values

County Site Name Site Number Design Value (μg/m3)

2008 2009 2010

Bucks Bristol 420170012 12.6 12.2 11.3

Chester New Garden 420290100 13.4 13.9 13.8

Delaware Chester 420450002 14.1 13.7 13.1

Montgomery Norristown 420910013 12.3 11.7 10.5

Philadelphia AMS Lab 421010004 13.4 12.5 11.5

Philadelphia NE Airport 421010024 12.4 11.5 10.5

Philadelphia Broad Street 421010047 14.5 13.0 11.9

Philadelphia Elmwood 421010136 13.2 13.3
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B. COMPONENTS OF PENNSYLVANIA’S ATTAINMENT PLAN

In accordance with section 172(c) of the CAA and the PM2.5 Implementation Rule, the 

attainment plan submitted on April 12, 2010 by PADEP for the Pennsylvania portion of the 

Philadelphia area included: (1) an emissions inventory for the plan’s base year (2002); (2) an 

attainment demonstration; and (3) MVEBs for the attainment year. The attainment 

demonstration includes: (a) technical analyses that locate, identify, and quantify sources of 

emissions contributing to violations of the 1997 annual PM2.5 NAAQS; (b) analyses of future 

year emissions reductions and air quality improvements expected to result from national and 

local programs from new measures to meet RACM/RACT; (c) adopted emission reduction 

measures with schedules for implementation; and (d) contingency measures for NOx and SO2 to 

be implemented if the area did not meet RFP or did not attain the standard by the attainment date. 

To analyze future year emissions reductions and air quality improvements, Pennsylvania

used local, regional, and national modeling analyses that have been developed to support Federal 

and local emission reduction programs. This modeling was performed in accordance with EPA’s 

“Guidance on the Use of Models and Other Analyses for Determining Attainment of Air Quality

Goals for Ozone, PM2.5, and Regional Haze” (EPA-454/B-07-002, April 2007). 

C. EPA’S REVIEW AND TECHNICAL INFORMATION

The following EPA analysis of the PM2.5 attainment plan for the Pennsylvania portion of 

the Philadelphia area, addresses all required elements of a PM2.5 attainment plan as described in 

the PM2.5 Implementation Rule (72 FR 20586).

 

I. Pollutants Addressed 

In accordance with policies described in the PM2.5 Implementation Rule, Pennsylvania’s 

PM2.5 attainment plan evaluates emissions of direct PM2.5, SO2, and NOx in the Pennsylvania 

portion of the Philadelphia area. Because of uncertainties regarding NH3 emission inventories 

and the efficacy of ammonia control technologies as noted earlier in this notice, the final rule sets 

forth the presumption that NH3 is not a PM2.5 precursor and that the states are not required to 

address NH3 in their attainment plan. Similarly, VOC emissions are presumed not to be an 

attainment plan precursor because of uncertainties regarding the role of VOC in secondary

organic aerosol formation. Pennsylvania’s attainment plan does not reverse this presumption.

II. Emissions Inventory Requirements

Section 172(c)(3) of the CAA requires states to develop emissions inventories of point, 

area, onroad mobile, and nonroad mobile sources for their attainment demonstrations. These 

inventories provide a detailed accounting of all emissions and emissions sources by precursor or 

pollutant. In addition, inventories are used to model air quality to demonstrate that attainment of 
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the 1997 PM2.5 NAAQS as expeditiously as practicable, and if an attainment extension beyond 

2010 is needed to support the need for such an extension. Emissions inventory guidance was 

provided in the April 1999 document “Emissions Inventory Guidance for Implementation of 

Ozone and Particulate Matter NAAQS and Regional Haze Regulations,” (EPA–454/R–99–006), 

which was updated in November 2005 (EPA–454/R–05–001). Emissions reporting requirements 

were provided in the 2002 Consolidated Emissions Reporting Rule (CERR) (67 FR 39602). On 

December 17, 2008 (73 FR 76539), EPA promulgated the Air Emissions Reporting 

Requirements (AERR) to update emissions reporting requirements in the CERR, and to 

harmonize, consolidate and simplify data reporting by states.

In accordance with the AERR and the November 2005 guidance, the PM2.5

Implementation Rule required states to submit inventory information on directly emitted PM2.5

and PM2.5 precursors and any additional inventory information needed to support an attainment 

demonstration.

PM2.5 is comprised of filterable and condensable emissions. Condensable particulate 

matter (CPM) can comprise a significant percentage of direct PM2.5 emissions from certain 

sources, and are required to be included in national emission inventories based on emission 

factors. Test Methods 201A and 202 are available for source-specific measurement of 

condensable emissions. However, the PM2.5 Implementation Rule acknowledged that there were 

issues and concerns related to availability and implementation of these test methods as well as 

uncertainties in existing data for condensable PM2.5. In recognition of these concerns, EPA 

established a transition period during which EPA could assess possible revisions to available test 

methods and to allow time for States to update emissions inventories as needed to address direct 

PM2.5, including condensable emissions. Because of the time required for this assessment, EPA 

recognized that States would be limited in how to effectively address CPM emissions, and 

established a period of transition, up to January 1, 2011, during which State submissions for 

PM2.5 were not required to address CPM emissions. Amendments to these test methods were 

proposed on March 25, 2009 (74 FR 12969), and finalized on December 21, 2010 (75 FR 

80118). The amendments to Method 201A added a particle-sizing device for PM2.5 sampling, 

and the amendments to Method 202 revised the sample collection and recovery procedures of the 

method to reduce the formation of reaction artifacts that could lead to inaccurate measurements 

of CPM emissions. 

The period of transition for establishing emissions limits for condensable direct PM2.5

ended on January 1, 2011. PM2.5 submissions made during the transition period are not required 

to address CPM emissions; however, States must address the control of direct PM2.5 emissions, 

including condensable emissions, with any new action taken after this January 1, 2011. 

Pennsylvania submitted the Pennsylvania portion of the Philadelphia area attainment plan prior 

to January 1, 2011 and did not consider condensables. 

In July 2008, EarthJustice filed a petition requesting reconsideration of EPA's transition 

period for CPM emissions provided in the PM2.5 Implementation Rule. In January 2009, EPA 
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decided to allow states that have not previously addressed CPM to continue to exclude CPM for 

PSD permitting during the transition period. Today’s action reflects a review of Pennsylvania’s 

submittal based on current EPA guidance as described in the PM2.5 Implementation Rule. More 

information and the review and evaluation of the methods used for the emissions inventory

submitted by Pennsylvania are found in section III of Pennsylvania’s attainment plan submittal 

and a TSD entitled, “Technical Support Document for the Pennsylvania Portion of the 

Philadelphia-Wilmington, PA-NJ-DE PM2.5 Noanattainment Area: State Implementation Plan 

Attainment Demonstration and Base Year Inventory,” dated October 11, 2011.

1. 2002 Base Year Emission Inventories

An emission inventory is an estimate of the emissions from sources in a particular area. 

PADEP developed an emission inventory for 2002, which is the base year for attainment 

planning purposes with respect to 8-hour ozone and PM2.5 SIPs and for planning purposes with 

respect to the regional haze SIPs. The 2002 base year inventory includes the pollutants PM10, 

PM2.5, SO2, NOx, VOC, and NH3. The inventory consists of four sectors: stationary point 

sources, stationary area sources, highway vehicle sources and nonroad sources. The MidAtlantic/Northeast Visibility Union (MANE-VU) compiled a regional inventory from the 

emission inventories of the Northeastern and Mid-Atlantic states. This regional inventory was 

used to perform the regional modeling analysis used in the Pennsylvania’s air quality

management effort to attain the 8-hour ozone NAAQS and the PM2.5 NAAQS, and to prepare the 

regional haze plan.

Stationary sources (or point sources) are sources for which PADEP collects individual 

emissions-related information. They generally represent major stationary sources but may be 

smaller. The point source data for 2002 is derived from the Air Information Management 

System/environment, Facility, Application, Compliance Tracking System (AIMS/eFACTS). The 

AIMS/eFACTS database is comprised of sources identified and inventoried by PADEP’s

regional and central offices through permitting, field inspections, and surveys. More information 

is found in Appendix B-1 of Pennsylvania’s attainment plan that includes information on 

stationary point source emission methodology, and Appendix B-2 is the data that set for facility

2002 annual emissions. Appendix B-3 is a table documenting banked emission reduction credits 

for the Pennsylvania portion of the Philadelphia area (5 counties) in the 2009 emission 

projection.

Area sources are industrial, commercial, and residential sources too small or too 

numerous to be handled individually. These include but are not limited to commercial and 

residential open burning architectural and industrial maintenance coatings applications and cleanup, consumer product use, and vehicle refueling at service stations. Where there is overlap 

between stationary point sources and stationary area sources, the area source values are adjusted 

to remove any double counting. PADEP’s inventory contained estimations of emissions by

multiplying an emission factor by an indicator or activity level for each category at the county
9

level. These emissions are calculated on an annual basis since the activity data are generally

available on an annual basis. Area source estimates were provided by source classification code 

(SCC). More information is found in Appendix C-1 of Pennsylvania’s attainment plan where 

specific information on the procedure used for each industry type is contained and Appendix C-2 

is a table containing stationary area source emissions data for the Pennsylvania portion of the 

Philadelphia area (5 counties).

Highway vehicles, which include passenger cars and light-duty trucks, other trucks, 

buses and motorcycles. Onroad mobile source emissions inventory was developed using the 

most current version of EPA’s highway mobile source emissions model MOBILE6.2. PADEP 

also used PPSUITE, an enhanced version of the Post Processor for Air Quality software systems 

used for previous inventory submissions in Pennsylvania. The Pennsylvania Department of 

Transportation (PennDOT) provided estimates of vehicles miles traveled (VMT) by vehicle type 

and roadway type. Pennsylvania’s methodology is consistent with the January 2002 guidance 

published by EPA’s Office of Transportation and Air Quality (OTAG) entitled, “Technical 

Guidance on the Use of MOBILE6 for Emissions Inventory Preparation.”

More information on highway emission methodology is available in Appendix E of the 

Pennsylvania’s attainment plan. Appendix E-1 provides the 2002 base year and 2009 projections 

of mobile (highway) VMT and annual PM2.5 direct and precursor emissions. The document 

summarizes the methodology and data inputs used to produce the mobile emissions inventory. 

Appendix E-2 is a table of 2009 five-county Philadelphia area annual highway emissions listed 

by SCC. Appendix E-3 describes the inputs to MOBILE6.2 used to generate emission factors for 

a specific area. Some examples of the inputs described in Appendix E-3 are the type and 

frequency of vehicle emission testing, the fuel types required in the area, temperatures by month, 

and fleet age. The summary in Appendix E-3 indicates when default information contained in 

the model is used rather than specific area information. Appendix E-4 is an electronic file that 

provides all of the input coding for a sample segment and scenario used in Pennsylvania’s 

MOBILE6.2 modeling system.

Nonroad sources encompass a diverse collection of engines, including but not limited to 

outdoor power equipment, recreational vehicles, farm and construction machinery, lawn and 

garden equipment, industrial equipment, recreational marine vessels, commercial marine vessels, 

locomotives, ships, and aircraft. The majority of nonroad emission source categories were 

estimated using the EPA NONROAD 2005 model. The NONROAD model estimates emissions 

for diesel, gasoline, liquefied petroleum gasoline, and compressed natural gas-fueled nonroad 

equipment types and includes growth factors. The NONROAD model does not estimate 

emissions from aircraft, locomotives or commercial marine vessels. Emissions from aircraft, 

locomotives or commercial marine vessels were estimated using EPA guidance and best 

available information. 

More information on nonroad sources is found in Appendix F of the Pennsylvania’s 

attainment plan. Appendix F-1 is the technical document providing the methodology and 
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description of the procedures used to generate 2002 and 2009 county-level pollutant emission 

estimates for nonroad mobile engines included in EPA’s NONROAD 2005 model, locomotive 

engines and aircraft operations. Appendix F-2 is a table of the specific emissions data used to 

calculate the nonroad emissions sorted by source category. Appendix F-3 contains the 2002 

Philadelphia International Airport (PHL) inventory that includes aircraft and aircraft-related 

equipment from the EPA-approved model, “Emissions and Dispersion Modeling System 

(EDMS),” and also additional on-airport highway, stationary and area source emissions. 

The emissions inventory for the base year, 2002, was developed in accordance with EPA 

guidance, “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards and Regional Haze Regulations, EPA-454/R-05-001, 

August 2005, updated November 2005.” Table 3 summarizes the emissions for 2002.

Table 3. 2002 Annual Emissions (Tons per Year)

Philadelphia area 2002 PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 2139 3430 23745 22124 8183 256

Area Sources 10020 55224 13153 13029 59227 4821

Highway Vehicle 

Sources

 1033 1492 1920 63476 33974 2614

Nonroad Sources 1535 1611 1640 21619 21589 14

Total 14727 61758 40459 120248 122973 7705

2. 2009 Projected Emission Inventories

Table 4 summarizes the emissions expected in 2009. These emissions take activity and 

emissions growth and/or controls from 2002 into account. Appendix D of the Pennsylvania’s 

attainment plan, relating to emissions projections, contains documents that describe the 

methodologies used to project the 2002 baseline emissions to 2009.

Table 4. 2009 Projected Emissions (Tons per Year)

Philadelphia area 2009 PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 2817 3840 12658 22252 7881 357

Area Sources 10324 59533 13972 13755 55868 5749

Highway Vehicle 

Sources

 699 1193 327 36318 20298 3118

Nonroad Sources 1356 1428 800 18874 15971 16

PHL Capacity

Enhancement Program

 0 0 0 0 254 0

Emission Reduction 

Credits Banked

 23 32 442 432 1561 0

Totals 15219 66035 28200 91651 101834 9239
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Sulfur and nitrogen are major contributors to the Pennsylvania portion of Philadelphia 

area’s PM2.5 nonattainment problem. Therefore, even though the direct PM2.5 emissions increase 

in 2009, the reductions of PM2.5 precursors, SO2 and NOx, ensures that the Philadelphia area 

attains the PM2.5 NAAQS by 2010.

3. Growth Projections Methodologies

Growth projections methodologies describe the data, methods and assumptions utilize in 

developing estimates of emissions changes between 2002 and the milestone year 2009. 

Appendix D-1 of the Pennsylvania’s attainment plan contains the technical support document 

entitled, “Development of Emission Projections for 2009, 2012, and 2018 for Non-EGU Point, 

Area, and Nonroad Sources in the MANE-VU Region,” developed by the Mid-Atlantic Regional 

Air Management Association (MARAMA). This document provides detail on the specific 

factors, control assumptions, and implementation schedules used in the emission projection 

calculations for each source category.

III. Attainment Demonstration - Modeling

All attainment demonstrations must include modeling that is performed in accordance 

with EPA’s “Guidance on the Use of Models and Other Analyses for Demonstrating Attainment 

of Air Quality Goals for Ozone, PM2.5, and Regional Haze” (EPA-454/B-07-002, April 2007). 

Modeling may be based on national (e.g., EPA), regional (e.g., Ozone Transport Commission), 

local modeling, or a combination thereof, if appropriate. A description of modeling used to 

support Philadelphia’s attainment demonstration follows. More detailed information on the 

modeling is discussed in a TSD entitled, “Technical Support Document for the Modeling Portion 

of the Commonwealth of Pennsylvania’s Fine Particulate Matter State Implementation Plan,”

dated October 11, 2011 and section V of the Pennsylvania’s attainment plan.

Based on 2006 – 2008 monitoring data, all monitors in the Pennsylvania portion of the 

Philadelphia area meet the EPA’s annual PM2.5 standard (15.0 μg/m3). The Philadelphia area’s 

maximum 2008 annual design value of 14.5 μg/m3 was observed at the Broad Street monitor. 

Based on 2006 – 2008 monitoring data, all monitors within the Philadelphia area are monitoring

attainment of the 1997 24-hour PM2.5 standard (65 μg/m3). The maximum 2008 24-hour design 

value in the Philadelphia area was 36 μg/m3, observed at the New Garden monitor. The 

Philadelphia area is required to attain the PM2.5 standard no later than five years from the 

effective date of designation of April 5, 2005 (April, 2010).

The purpose of the attainment demonstration is to ensure, through grid modeling, that 

projected emissions (with controls) will not cause the nonattainment area to exceed the 1997 

PM2.5 NAAQS. A complex grid model was run and processed over the entire Northeast to 

determine if the Philadelphia area would attain the PM2.5 standard by April 5, 2010. 
12

Philadelphia Area Conceptual Model Description

A conceptual model describes how weather patterns affect the formation and transport of 

PM2.5, accounting for emissions and photochemistry.

The conceptual model for the Philadelphia area was based on information from the 

Northeast States for Coordinated Air-Use Management (NESCAUM) final report entitled, “The

Nature of the Fine Particle and Regional Haze Air Quality Problems in the MANE-VU Region: 

A Conceptual Description (2006)” and PADEP’s modeling protocol documentation (October 

2007).

The NESCAUM document contains a conceptual description that explains how elevated 

regional PM2.5 peak concentrations in the summer differ significantly from the largely urban peak 

concentrations observed during winter. On average, summertime concentrations of sulfate in the 

northeastern United States are more than twice that of the next most important fine particle 

constituent, organic carbon (OC), and more than four times the combined concentration of nitrate 

and black carbon (BC) constituents. Episodes of high summertime sulfate concentrations are 

consistent with stagnant meteorological flow conditions upwind of the Pennsylvania portion of 

the Philadelphia area and the accumulation of airborne sulfate (via atmospheric oxidation of SO2) 

followed by long-range transport of sulfur emissions from industrialized areas within and outside 

the area. National assessments have indicated that in the winter, sulfate levels in urban areas are 

higher than background sulfate levels across the eastern U.S., indicating that the local urban 

contribution to wintertime sulfate levels is significant relative to the regional sulfate contribution 

from long-range transport. A network analysis for the winter of 2002 suggests that the local 

enhancement of sulfate in urban areas of the MANE-VU region ranges from 25 to 40% and that 

the long-range transport component of PM2.5 sulfate is still the dominant contributor in most 

eastern cities.

In the winter, urban organic carbon (OC) and sulfate each account for about a third of the 

overall PM2.5 mass concentration observed in Philadelphia and New York City areas. Nitrate 

also makes a significant contribution to urban PM2.5 levels observed in the northeastern United 

States during the winter months. Wintertime concentrations of OC and nitrate in urban areas can 

be twice the average regional concentrations of these pollutants, indicating the importance of 

local source contributions. This is likely because winter conditions are more conducive to the 

formation of local inversion layers which prevent vertical mixing. Under these conditions, 

emissions from tailpipe, industrial and other local sources become concentrated near the Earth’s 

surface, adding to background pollution levels associated with regionally transported emissions. 

The Model Used in the Attainment Demonstration 

By agreement of OTC, the New York State Department of Environmental Conservation 
13

(NYSDEC) ran the Community Multi-scale Air Quality Model (CMAQ) for the states in the 

northeast ozone transport region that includes Pennsylvania. EPA agrees CMAQ is appropriate 

for this modeling demonstration. The inputs of the model are described in section V of the 

attainment plan submittal. 

Meteorological Time Periods Used in the Modeling

Since the Philadelphia area’s attainment demonstration used a resource intensive 

photochemical grid model, EPA accepts the use of single, recent representative year to be used 

for an annual simulation. Two factors were used in selecting 2002 as the representative year: the 

observed annual mean concentrations of PM2.5 are close to the 3-year observed design value at 

all, or most monitoring sites, and the pattern of quarterly mean values is similar to the pattern of 

quarterly mean concentrations averaged over 3 years.

Meteorological Data Used in the Air Quality Model 

The OTC modeling committee decided to use a prognostic meteorological model that 

provides life-like meteorological inputs to the photochemical grid model. The Pennsylvania 

State University/National Center for Atmospheric Research Mesoscale Meteorological Model 

(MM5) version 3.6 was chosen for the modeling analysis. The MM5 model provides a 

reasonable representation of weather conditions at the surface and aloft. 

Domain of the Model, Horizontal/Vertical Resolution and the Initial and Boundary 

Conditions 

The modeling domain extends from Maine to Florida and out in the Atlantic Ocean on the 

east and west to the Mississippi River. The size of the modeling domain was made large enough 

to include all emission sources that affect PM2.5 concentration in the northeastern United States. 

Even this boundary is defined by a larger photochemical modeling domain that covers much of 

North America. Over the northeastern United States, the model used 12 kilometer grid cells. 

The Pennsylvania portion of the Philadelphia area is included in the 12 kilometer grid cell area. 

The OTC Modeling Committee used a 12-kilometer grid size for the areas in and near its states 

to provide a fine enough grid resolution to adequately capture the PM patterns experienced in the 

ozone transport region (OTR). Outside the local areas the grid resolution used in the modeling is 

36 kilometers. The selection of model domains and horizontal grid resolution was deemed 

acceptable to EPA.

Vertical resolution is the number of layers and the size of each layer in the model. The 

layers in the photochemical grid model were set up to be compatible with the model that 

produced weather conditions for the photochemical grid model. The vertical resolution used in 

the modeling exercise followed EPA’s modeling guidance and therefore adequately represents 

the atmosphere where PM2.5 is emitted, forms and is transported. 
14

Emissions Used in the Air Quality Model 

The emissions data for 2002 were generated by individual states within the OTR and 

assembled and processed through Mid-Atlantic Northeast Visibility Union (MANE-VU), a 

Regional Planning Organization (RPO). These emissions were then processed by NYSDEC 

using the sparse matrix operator kernel emissions (SMOKE) emissions processor to provide 

CMAQ compatible inputs. The 2002 emissions for the non-OTR areas within the modeling 

domain were obtained from the corresponding RPOs and were processed using SMOKE, in 

manner similar to that of the OTR emissions. The OTR states, through MANE-VU, contracted 

MACTEC Federal Programs (called Contractor) to develop 2009, 2012 and 2018 inventories 

based on 2002 inventories that the states had previously developed for the base-year model work. 

The Contractor, in consultation with the states, developed the necessary growth and control 

factors and applied to the 2002 inventory. 

Base Case Run Model Performance Evaluation 

NYSDEC performed a model evaluation for the OTC to determine how well CMAQ 

reproduced the 2002 PM2.5 concentrations. CMAQ was employed to simulate PM2.5 for the 

calendar year 2002. A review of PM2.5 and its individual species was conducted for the study

domain. Several observations were made with respect to model performance: 1) approximately

80 – 90 percent of organic mass (OM) is in the primary fraction; 2) CMAQ captures seasonal 

variation in SO4 well; 3) CMAQ appears to overestimate primary PM2.5 components, especially

during colder months; and CMAQ appears to underestimate secondary OM during the summer.

These issues are not of great regulatory concern since attainment tests are based on the 

application of relative response factors. Therefore, the regional and local model performance is 

acceptable for PM2.5. While there are some differences between the spatial data between subregions, 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 OTC 

domain. This confidence in the modeling results allows for the modeling system to be used to 

support the attainment plan to meet the 1997 annual PM2.5 NAAQS.

2009 Control Case Modeling and Modeled Attainment Test 

As previously mentioned, the Pennsylvania portion of the Philadelphia area has an 

attainment date of April 5, 2010. The PM2.5 NAAQS include an annual standard of 15 μg/m3

based on the 3-year average of annual mean PM2.5 concentrations.
15

The purpose of a modeling assessment is to determine if control strategies currently being 

implemented (“on the books”) will lead to attainment of the annual average NAAQS for PM2.5 by

2009. The modeling is applied in a relative sense, similar to the 8-hour ozone attainment test. 

However, the PM2.5 attainment test is more complicated and reflects the fact that PM2.5 is a 

mixture. In the test, ambient PM2.5 is divided into major components, with a separate relative 

response factor (RRF) and future design value (DVF) calculated for each of the PM2.5 

components. Since the attainment test is calculated on a per species basis, the attainment test for 

PM2.5 is referred to as the Speciated Modeled Attainment Test (SMAT).

Annual SMAT Results

Table 4 presents the results of the annual SMAT results for the Philadelphia area. The 

SMAT results demonstrate that the projected average annual arithmetic mean PM2.5

concentration calculated at each Federal Reference Method (FRM) monitor attains the annual 

PM2.5 NAAQS. Specifically, all calculations are less than15 μg/m3. Table 4 presents the results 

of the annual SMAT results for a suite of regional modeling runs conducted by OTC each 

representing OTB/OTW – “On the Books, On the Way” control measures. All runs demonstrate 

compliance with the annual PM2.5 NAAQS.

Table 4. Annual SMAT Results for Philadelphia-Wilmington, PA-NJ-DE PM2.5

Nonattainment Area On-The-Books-On-The-Way Control Measures

In summary, the basic photochemical grid modeling, presented in the Philadelphia area 

AIRS ID

Site 

Name County State

2000-2004 Baseline Design Value 2009

Q1 Q2 Q3 Q4 DVF

420170012 Bristol Bucks PA 14.14 13.69 14.73 13.85 12.1

420290100 New Garden Chester PA 14.39 14.73 16.36 13.76 12.4

420450002 Chester Delaware PA 15.07 15.96 16.34 13.74 13.3

420910013 Norristown Montgomery PA 12.68 13.62 13.96 12.34 11.3

421010004 AMS Lab Philadelphia PA 15.99 14.01 15.95 13.82 12.9

421010024 NE Airport Philadelphia PA 13.58 13.63 14.95 12.96 11.9

421010047 Broad Street Philadelphia PA 16.59 16.45 15.80 15.37 13.5

421010136 Elmwood Philadelphia PA 15.70 14.20 15.27 12.99 12.7

100031003 Bellefonte New Castle DE 14.87 15.16 15.50 13.13 12.6

100031007 Lums Pond New Castle DE 13.16 14.37 16.05 10.66 11.3

100031012 Newark New Castle DE 15.27 14.91 16.53 13.14 12.6

100032004 MLK New Castle DE 16.41 15.40 17.61 14.04 13.3

340070003 Camden Camden NJ 13.99 14.54 15.76 12.47 12.3

340071007 Pennsauken Camden NJ 13.99 14.00 14.75 13.59 12.3

340155001 Gibbstown Gloucester NJ 13.92 13.43 15.08 11.39 11.7
16

attainment plan, used the methods recommended in EPA’s modeling guidance. When EPA’s 

attainment test is applied to the modeling results, the 2009 annual-average PM2.5 design value is 

predicted to be 13.5μg/m3 in the Philadelphia area. Therefore, based on EPA’s modeled 

attainment test, the Pennsylvania portion of the Philadelphia area reached attainment of the 

annual average PM2.5 standard in 2009 before the attainment date of April 5, 2010. 

Supplemental Analyses and Weight of Evidence (WOE) Determination

EPA’s modeling guidance states that additional analyses are recommended to determine 

if attainment will be likely, even if the modeled attainment test is “passed.” The guidance 

recommends supplementary analyses in all cases. EPA’s modeling guidance describes how to 

use a photochemical grid model and additional analytical methods to complete a WOE analysis 

to estimate if emissions control strategies will lead to attainment. A WOE analysis is a 

supporting analysis that helps to determine if the results of the photochemical modeling system 

are correctly (or not correctly) predicting future air quality. 

All models, including the CMAQ, model have inherent uncertainties. Over or under 

prediction may result from uncertainties associated with emission inventories, meteorological 

data, and representation of PM2.5 chemistry in the model. Therefore, EPA modeling guidance 

provides for other evidence to address these model uncertainties so that proper assessment of the 

probability to attain the applicable standards can be made. EPA modeling guidance states that 

those modeling analyses that show that attainment with the NAAQS will be reached in the future 

with some margin of safety (i.e., estimated concentrations below 14.5 μg/m3for annual PM2.5 and 

62 μg/m3for 24-hour PM2.5) need more limited supporting material. 

Due to the fact that the modeling results presented in Table 4 fall below the 

aforementioned “weight of evidence” thresholds established by EPA, a limited supplemental 

analysis was deemed necessary to support the 2009 attainment demonstration. PADEP’s 

supporting evidence includes a brief summary of the modeling demonstration, recent trends in 

the Philadelphia area’s monitoring data and a brief analysis of some of the largest SO2 sources 

within the nonattainment area (section V of Pennsylvania’s attainment plan). 

IV. Reasonably Available Control Measures/Reasonably Available Control Technology

1. Requirements for RACM/RACT

CAA section 172(c) (1) requires that each attainment plan “provide for the 

implementation of all RACM as expeditiously as practicable, including such reductions in 

emissions from the existing sources in the area as may be obtained through the adoption, at a 

minimum, of RACT, and shall provide for attainment of the national primary ambient air quality

standards.” EPA interprets RACM including RACT under section 172 as measures that a state 

finds are both reasonably available and contribute to attainment as expeditiously are practicable 
17

in the nonattainment area. Thus, what constitutes RACM or RACT in a PM2.5 nonattainment 

area is closely tied to the expeditious attainment demonstration of the plan. See 40 CFR section 

51.1010; 72 FR 20586 at 20612. 

States are required to evaluate RACM/RACT for direct PM2.5 emissions and all of the 

area’s attainment plan precursors. See 40 CFR section 51.1002 (c); 72 FR 20586 at 20589 - 97. 

Consistent with the guidance provided for the PM2.5 Implementation Rule, a state initially must 

evaluate RACM/RACT for sources that emit direct PM2.5, SO2, and NOx. A state may establish 

with an appropriate demonstration that it should not regulate NOx in the specific nonattainment 

area, so it could thereby forgo evaluation of RACM/RACT for NOx. Because EPA concluded

that VOC and NH3 are presumptively not regulatory precursors for PM2.5, unless the state or EPA 

determines that it is necessary to regulate them in a specific nonattainment area, the state is not 

required to evaluate RACM/RACT for sources of VOC or NH3 unless there is a determination 

supported by an appropriate demonstration that such emissions need to be regulated for 

expeditious attainment of the NAAQS in the specific area.

For PM2.5 attainment plans, the PM2.5 Implementation Rule requires a combined approach 

to RACM and RACT under subpart 1 of Part D of the CAA. Subpart 1, unlike subparts 2 and 4, 

does not identify specific source categories for which EPA must issue control technique 

documents or guidelines, or identify specific source categories for state and EPA evaluation 

during attainment plan development. See 72 FR 20586 at 20610. Rather, under subpart 1, EPA 

considers RACT to be part of an area’s overall RACM obligation consistent with the section 172 

definition. Because of the variable nature of the PM2.5 problem in different nonattainment areas 

which may require states to develop attainment plans that address widely disparate 

circumstances, EPA determined not only that states should have flexibility with respect to 

RACM/RACT controls but also that in areas needing significant emission reductions, 

RACM/RACT controls on smaller sources may be necessary to reach attainment as expeditiously

as practicable. See 72 FR 20586 at 20612, 20615. Thus, under the PM2.5 Implementation Rule, 

RACM and RACT are those reasonably available measures that contribute to attainment as 

expeditiously as practicable in the specific nonattainment area. See 40 CFR section 51.1010; 72 

FR 20586 at 20612.

Specifically, the PM2.5 Implementation Rule requires that attainment plans include the list 

of measures that a state considered and information sufficient to show that the state met all 

requirements for the determination of what constitutes RACM/RACT in a specific nonattainment 

area. See 40 CFR section 51.1010(a). In addition, the PM2.5 Implementation Rule requires that 

the state, in determining whether a particular emissions reduction measure or set of measures 

must be adopted as RACM/RACT, consider the cumulative impact of implementing the available 

measures and to adopt as RACM/RACT any potential measures that are reasonably available 

considering technological and economic feasibility if, considered collectively, they would 

advance the attainment date by one year or more. If a measure or measures is not necessary for 

expeditious attainment of the NAAQS in the area, then by definition that measure is not 

RACM/RACT for purposes of the 1997 PM2.5 NAAQS in that area. Any measures that are 
18

necessary to meet these requirements which are not already either Federally promulgated, part of 

the state’s SIP, or otherwise creditable in SIPs must be submitted in enforceable form as part of a 

state’s attainment plan for the area. See 72 FR 20586 at 20614. 

Guidance provided in the PM2.5 Implementation Rule for evaluating RACM/RACT level 

controls for an area also indicated that there could be flexibility with respect to those areas that 

were predicted to attain the 1997 PM2.5 NAAQS within five years of designation as a result of 

existing national or local measures. See 72 FR 20586 at 20612. In such circumstances, EPA 

indicated that the state may conduct a more limited RACM/RACT analysis that does not involve 

additional air quality modeling. Moreover, the RACM/RACT analysis for such area would focus 

on a review of reasonably available measures, the estimation of potential emissions reductions, 

and the evaluation of the time needed to implement the measures. Thus, the PM2.5

Implementation Rule guidance recommended that not all areas would need to conduct as rigorous 

an analysis, and suggested that a less rigorous analysis would be needed for those areas expected 

to attain within the initial five years from designation as a nonattainment area for the 1997 PM2.5

NAAQS.

A more comprehensive discussion of the RACM/RACT requirement for PM2.5 attainment 

plans and EPA’s guidance for it can be found in the PM2.5 Implementation Rule preamble. See

72 FR 20586 at 20609 – 20633.

2. Pennsylvania’s Analysis of Pollutants and Sources Pennsylvania Portion of the 

Philadelphia Area.

Pennsylvania’s analysis appears in section IV.B, page 29 and Appendices G-1, G-2 and 

G-3 of the attainment plan submission. Based upon the emissions inventory for the area, 

Pennsylvania determined that it would be appropriate to evaluate sources of PM2.5, SO2, and 

NOx located in the nonattainment area for potential control as RACM/RACT. Pennsylvania did 

not determine that controls of sources of VOC or NH3 would be necessary for expeditious 

attainment of the NAAQS in this area, nor does EPA believe that there is a need to do so. 

Pennsylvania’s determination with respect to which pollutants the plan should evaluate is at 

section I.B, page 1 of the attainment plan submittal.

After evaluating which pollutants should be addressed in the attainment plan, 

Pennsylvania identified all source categories of those emissions located within the nonattainment 

area to determine available controls that could bring the area into attainment as expeditiously as 

possible. See section IV.B of the attainment plan submittal. Based on the emissions inventory

and other information, Pennsylvania identified the following source categories as sources that 

should be evaluated for controls: 

- Consumer Products

- Portable Fuel Containers
19

- Adhesives and Sealants Application

- Diesel Engine Chip Reflash

- Cutback and Emulsified Asphalt Paving

- Cement Kilns

- Glass Furnaces

- Industrial, Commercial, and Institutional (ICI) Boilers

- Regional Fuels

- Electric Generating Units (EGUs)

Appendix G-1 of the attainment plan submittal contains the Ozone Transport 

Commission (OTC) report entitled, “Identification and Evaluation of Candidate Control 

Measures, Final Technical Support Document (MACTEC, February 2007).” This final report 

contains detailed information about the process and includes tables summarizing the emission 

reduction potential of each control measure by source category and projection year. 

Pennsylvania also participated in an assessment of control measures for pollutants and 

sources affecting visibility though the MANE-VU regional haze process. MANE-VU developed 

a list of control measures for consideration and analysis:

- Coal and oil-fired EGUs

- Point and area source industrial, commercial and institutional boilers

- Cement kilns

- Lime kilns

- The use of heating oil

- Residential wood combustion and open burning

Appendix G-3 of the attainment plan submittal, contains the final report entitled, 

“Assessment of Reasonable Progress for Regional Haze in MANE-VU Class I Areas (MACTEC, 

July 2000),” from the MANE-VU control measure assessment project. This report presents the 

results of an analysis of the economic and environmental impacts of the potential scenarios that 

could be implemented by MANE-VU states to reduce emissions from selected source categories 

in order to make reasonable progress toward meeting visibility improvement goals.

In accordance with 40 CFR 51.1010, a SIP revision for a PM2.5 nonattainment area is 

required to demonstrate that all RACM, including RACT stationary sources necessary to 

demonstrate attainment as expeditiously as practicable have been adopted. The cumulative 

impact of implementing available measures must be considered in determining whether a 

particular emission reduction measure or set of measures is required to be adopted as RACM. 

Potential measures that are reasonably available considering technical and economic feasibility

must be adopted as RACM if, considered collectively, they would advance the attainment date by

one year or more. Since the Pennsylvania portion of the Philadelphia area attained at the end of 

2009, any RACM measures need to be in effect in 2008. PADEP determined that there are no 

additional control measures that could be adopted by January 1, 2008. In addition, existing 
20

measures and measures planned for implementation by 2009, enables the Philadelphia area to 

attain the 1997 PM2.5 NAAQS. Therefore, no further actions on RACM or RACT are warranted.

3. Pennsylvania’s evaluation of RACM/RACT control measures for the Pennsylvania 

Portion of the Philadelphia Area.

In accordance with section 172 of the CAA, the Pennsylvania portion of the Philadelphia 

area has adopted all RACM, including RACT, needed to attain the standards “as expeditiously as 

practicable.” Pennsylvania’s demonstration for attaining the 1997 annual PM2.5 NAAQS in the 

Pennsylvania portion of the Philadelphia area is based on enforceable measures.

a. STATIONARY POINT SOURCES

Small Sources of NOx, Cement Kilns and Large Stationary Internal Combustion Engines

PADEP established additional ozone season requirements for small sources of NOx in the 

counties of Bucks, Chester, Delaware, Montgomery, and Philadelphia in regulations that were 

adopted on December 11, 2004 and approved by EPA on September 29, 2006 (71 FR 57428).

New Source Review Programs

The Federal New Source Review (NSR) programs are preconstruction review and 

permitting programs applicable to new or modified major stationary sources subject to Title I, 

Parts C and D of the CAA. The programs consist of the Prevention of Significant Deterioration 

(PSD) requirements applicable in areas attaining the NAAQS, and the nonattainment NSR 

requirements applicable in geographic areas not attaining and maintaining the NAAQS. 

PADEP’s PSD regulations (25 Pa. Code Chapter 127, Subchapter D, were approved by EPA on 

August 21, 1984 (49 FR 33128) codified at 40 CFR 52.2058. The Federal PSD regulations 

codified in 40 CFR 52 are incorporated by reference in 25 Pa. Code 127.83. The PSD program 

requires any new source to implement best available control technology (BACT) and limits new 

source’s allowable impact on the environment.

Federal Standards for Hazardous Air Pollutants

Federal standards to control hazardous air pollutants (HAPs) require maximum available 

control technology (MACT) at units located at major sources of HAPs. EPA has issued a series 

of regulations that are applicable to sources in Pennsylvania. These MACT standards are 

adopted and incorporated by reference in Section 6.6 of the Pennsylvania’s Air Pollution Control 

Act, implementing regulations and also included as Federally enforceable permits issued by

PADEP for affected sources.
21

Source Surveillance

PADEP’s rules and regulations for stationary sources, which are part of the control 

strategy for attaining the PM2.5 NAAQS, as well as PADEP’s comprehensive permitting program 

requirements in 25 Pa. Code Chapter 127 and Pennsylvania’s SIP in 40 CFR 52.2020, meet the 

requirements of 40 CFR Part 51, subpart K (relating to source surveillance). Pursuant to 40 CFR 

Part 51, subpart K, a SIP revision is required to provide for monitoring the status of compliance 

with rules and regulations set forth any portion of the control strategy. These include provisions, 

as applicable for: (1) emission reports and recordkeeping for stationary sources; (2) periodic 

testing and inspection of stationary sources; (3) enforcement and complaint investigation of 

visible emission limitations; (4) enforceable test methods for emission limits; and (5) continuous 

emission monitoring for stationary sources.

b. HIGHWAY VEHICLES

Even with increases in vehicles miles traveled (VMT) that occur from 2002 through 

2009. Highway vehicle emissions will continue to decrease. As more vehicles subject to cleaner 

new car standards replace older vehicles subject to less stringent new vehicle standards, the fleet 

as a whole emit fewer emissions, compensating for the increase in VMT. These decreases are 

attributed to the programs described below.

Federal Motor Vehicle Control Programs and Pennsylvania Clean Vehicle Program for 

Passenger Vehicles and Light-Duty Trucks and Cleaner Gasoline

Tier 1 tailpipe standards established by the CAA include NOx and VOC limits for lightduty gasoline vehicles (LDGVs) and light-duty gasoline trucks (LDGTs). These standards began 

to be phased in 1994. Evaporative VOC emissions were reduced in gasoline-powered cars 

starting with Model Year (MY) 1998.

In 1998, under the authority of section 177 of the CAA, PADEP adopted the 

Pennsylvania Clean Vehicles Program (28 Pa. B. 5873, Dec. 5, 1998). The Pennsylvania Clean 

Vehicles Program incorporates by reference certain California Low Emission Vehicle (CA LEV) 

emission standards for passenger cars and light-duty trucks. As required under Section 177 of 

the CAA, these provisions are identical to the low emission standards adopted by California. 

The regulation does not incorporate by reference the California zero emissions vehicle (ZEV) or 

emissions control warranty systems statement provisions.

PADEP adopted the National Low Emission Vehicle (NLEV) program as a compliance 

alternative to the Pennsylvania Clean Vehicles Program. The NLEV program became effective 

in the Ozone Transport Region (OTR) in 1999. Pennsylvania’s New Motor Vehicle Emissions 

Control Program regulations in 25 Pa. Code Sections 126.401-126.441 allowed automobile 

manufacturers to comply with NLEV instead of the CA LEV program through MY 2005. These 

regulations affected vehicles 6,000 pounds and less and were the regulations in effect for new 
22

motor vehicles in the baseline year, 2002. 

In 1999, EPA promulgated regulations more stringent than NLEV (Tier 2), starting with 

MY 2004. In order to participate in NLEV, Pennsylvania had been required to adopt language 

that extended its “commitment” to NLEV until MY 2006. In practical terms, the NLEV program 

was replaced for MY 2004 and later by the more stringent Federal “Tier 2” vehicle emissions 

regulations, 65 FR 6698 (Feb. 10, 2000), and vehicle manufacturers operating under the NLEV 

program became subject to the Tier 2 requirements. 

Pennsylvania amended the former New Motor Vehicle Control Program (which 

included the Pennsylvania Clean Vehicles Program) in 2006. The Clean Vehicles Program 

continues to incorporate the California Low Emission Vehicle Program (CA LEV II) by

reference. As amended, the program affects MY 2008 and newer passenger cars and light-duty

trucks vehicles. 36 Pa. B. 7424 (Dec. 9, 2006). 

Emissions for milestone years were estimated based on compliance with the 

Pennsylvania Clean Vehicles Program according to the methodology described in section 7.4.1 of 

the “Technical Guidance on the Use of MOBILE6.2 for Emissions Inventory Preparation,”

published by the EPA’s OTAQ in January 2002. This methodology is further explained in 

Appendix E of Pennsylvania’s attainment plan. PADEP’s MOBILE modeling of the Federal Tier 

2 program applies to subject vehicles sold in Pennsylvania from MY 2004 through MY 2007 and 

the Pennsylvania Clean Vehicles Program applies to subject vehicles sold in MY 2008 and 

beyond.

Reformulated gasoline

 Gasoline sold in the Philadelphia area is required by the CAA to be the cleaner-burning 

reformulated gasoline meeting standards established in section 211 of the CAA. This federallyenforced program has been in place since January 1995. 

Heavy-Duty Diesel Control Programs

 EPA promulgated more stringent national regulations for heavy-duty engines and vehicles 

(over 14,000 pounds) starting with MY 2004. In addition, consent decrees with seven of the 

largest heavy-duty engine manufacturers required, among other terms, that diesel engines made 

by these companies comply with these 2004 standards two model years early, in MY 2002. 

Pennsylvania includes these programs as provided in the MOBILE model. 

Vehicle Emission Inspection/Maintenance Program

The Philadelphia area has had a vehicle emissions inspection program since 1984. In

early 2004, Pennsylvania revised the implementation of its Vehicle Emission 

Inspection/Maintenance (I/M) Program in the five-county Philadelphia area. The program 
23

applies to gasoline-powered vehicles 9,000 pounds and under, MY 1975 and newer. For vehicles 

MY 1996 and newer, the program consists of an annual on-board diagnostics test and a gas cap 

pressure test. For subject vehicles MY 1995 and older, the program consists of an annual tailpipe 

test, visual inspection of pollution control devices to ensure they are present, connected and the 

proper type for the vehicle and a gas cap pressure test. For vehicles older than 25 years, the 

program is a visual inspection and gas cap test. These regulations can be found in 67 Pa. Code

Chapter 177. Pennsylvania submitted the revised emissions program as a SIP revision on 

December 1, 2003 which EPA approved on October 6, 2005 (70 FR 58313).

Low sulfur gasoline

Simultaneously with the Tier 2 program, EPA published a regulation requiring the 

reduction of sulfur in gasoline beginning in 2004, with full implementation in 2006. Sulfur 

levels are capped at 80 ppm per gallon and annual refinery averages must be no more than 30 

ppm. The emission reduction analysis uses the default assumptions provided in MOBILE6 to 

account for the implementation of the Federal sulfur standard rule. 

Diesel Vehicle Idling Restrictions

On October 9, 2008, Governor Rendell signed the Diesel-Powered Commercial Motor 

Vehicle Idling Act (Act 124 of 2008). Act 124 of 2008 went into effect on February 6, 2009. 

This Act restricts subject drivers and owners statewide from idling a diesel-powered motor 

vehicle engaged in commerce with a gross vehicle weight of 10,001 pounds or more for more 

than five minutes in any continuous 60-minute period. Also, no owner or operator of a location 

where the aforementioned vehicles load, unload or park may allow the vehicles to idle for more 

than 5 minutes in a 60-minute continuous period. 

c. NONROAD SOURCES

EPA adopted a series of regulations affecting new diesel-powered (“compression 

ignition”) and gasoline-powered (“spark ignition”) nonroad engines of various sizes 

(horsepower) and applications. Information on these Federal rules, including their 

implementation dates, can be found at www.epa.gov/nonroad. PADEP used the assumptions 

built into the nonroad model (NONROAD2005) to estimate emissions for all milestone years.

EPA will also require diesel fuel used in most nonroad applications to contain less sulfur. 

The sulfur will prevent damage to the more advanced emission control systems needed to meet 

the engine standards; it will also reduce fine particulate emissions from diesel engines. In 2007, 

fuel sulfur levels were limited to 500 parts per million (ppm) for nonroad applications other than 

ocean-going marine vessels. In 2010, fuel sulfur levels will be reduced to the same sulfur 

concentration as in highway fuel, 15 ppm; this requirement applies in 2012 to locomotive and 

marine diesel fuel.
24

d. VOC SOURCES

Although VOC is not a regulated PM2.5 precursor for the Philadelphia area, VOC control 

measures approved by EPA were included in the modeling associated with this attainment plan: 

portable fuel containers (December 8, 2004, 69 FR 70893); consumer products (December 8, 

2004, 69 FR 70895); and architectural and industrial maintenance (AIM) coatings (November 23, 

2004, 69 FR 69080).

4. RACM/RACT Demonstration and Control Strategy

Pennsylvania’s evaluation of RACM/RACT control measures for the Pennsylvania 

portion of the Philadelphia area is approvable. As noted above, the most current monitoring data 

for this area indicates that it is attaining the 1997 PM2.5 NAAQS. EPA’s guidance for the PM2.5

Implementation Rule recommended that if an area was predicted through the attainment plan to 

attain the standards within five years after designation, then the State could submit a more 

limited RACM/RACT analysis and the State could elect not to do additional modeling. 

In light of the fact that the Pennsylvania portion of the Philadelphia area is now attaining 

the standards, the attainment plan meets the RACM/RACT requirements of the PM2.5

Implementation Rule, and that the level of control in the State’s attainment plan constitutes 

RACM/RACT for purposes of the 1997 PM2.5 NAAQS. Because the PM2.5 Implementation Rule 

defines RACM/RACT as that level of control that is necessary to bring the area into attainment, 

the current level of Federally enforceable controls on sources located within the Philadelphia area 

is by definition RACM/RACT for this area for this purpose. 

VI. Contingency Measures

In accordance with Section 172(c)(9) of the CAA, the PM2.5 Implementation Rule 

requires that PM2.5 attainment plans include contingency measures. These measures must be 

fully adopted and should contain trigger mechanisms and an implementation schedule. In 

addition, they should be measures not already included in the SIP control strategy and should 

provide for emission reductions equivalent to one year of RFP. Contingency measures are 

implemented if RFP targets are not achieved, or if attainment is not realized by the attainment 

date. Where an area has already achieved attainment by the attainment date, it has no need to 

rely on contingency measures to come into attainment or to make further progress to attainment. 

However, in accordance with section 110(k)(2) of the CAA, EPA must take action on the 

contingency measures that were submitted by Pennsylvania.

The PM2.5 Implementation Rule requires that quantity of emission reductions needed to 

satisfy contingency requirements is an amount equal to one’s year worth of required reductions. 

Required reductions are the amount of reductions needed to attain compliance with the PM2.5
25

NAAQS. By 2009, emissions of SO2 and NOx in the Pennsylvania portion of the Philadelphia 

area are projected to decrease by 12,259 tons and 28597 tons, respectively. Based on modeling 

of the projected 2009 emissions, the Philadelphia area is predicted to have a design value of 13.5 

g/m3, which is lower than the 15 g/m3 required for the attainment of the PM2.5 NAAQS. 

Calculations were made to estimate the portion of the emission reduction that is necessary to 

reach the attainment concentration of 15 g/m3 and the portion of the emission reduction that 

reduces the design value below 15 g/m3 and is therefore, excess.

Table 5 displays the 2002 actual and 2009 modeled design values and the 2002 actual and 

2009 projected emissions of SO2 and NOx.

Table 5. Design Value and Emissions Expected by 2009 

Philadelphia area Design Value (g/m3

) SO2 (tons/year) NOx (tons/year)

2002 16.6 40459 120348

2009 (Modeled/Projected) 13.5 28200 91651

Change from 2002-2009 3.1 12259 28597

Table 6 shows that for each pollutant, the change in pollutant emissions was divided by

the change in design value to yield the value reduction rate. Then, the change in design value 

necessary to attain the standard (16.6 g/m3– 15 g/m3= 1.6 g/m3) was multiplied by the design 

value reduction rate to estimate the target emissions reduction. This represents the portion of 

emission reduction necessary to attain the standard. The rest of the emissions reduction is 

beyond what is necessary for attainment and is therefore, considered to be “excess” reduction.

Table 6. Calculation of Required and Excess Emissions Reductions

Philadelphia area Design Value (g/m3

) SO2 (tons/year) NOx (tons/year)

Change from 2002-2009 3.1 12259 28597

Design Value Reduction 

Rate (tons/g/m3)

3955 9225

Target Reductions for 

Attainment

1.6 6327 14760

Calculated Excess 

Reductions

1.5 5932 13837

The contingency requirement is calculated by dividing the target emissions reduction by

seven, which is the number of years between 2002 and 2009. Table 7 shows the calculation of 

the contingency requirement reduction and demonstrates that the calculated excess reduction 

exceeds the amount of reduction necessary for the contingency plan.

Table 7. Calculation of Required Contingency Plan Reductions
26

Philadelphia area SO2 (tons/year) NOx (tons/year)

Target Reductions for Attainment 6327 14760

Calculated Excess Reductions 5932 13837

Contingency Requirement 904 2109

Excess Reductions Satisfy Contingency

Requirement

Yes Yes

The attainment plan for the Pennsylvania portion of the Philadelphia area includes 

contingency measures to be implemented if the area fails to attain by its attainment date. The 

following describes the specific control measures that are anticipated to be in place in order to 

bring the area back into attainment should a violation occur. 

The Diesel-Powered Commercial Motor Vehicle Idling Act (Act 124) went into effect on 

February 6, 2009. PADEP estimates 50 percent of all long duration idling for Class 8 trucks will 

be eliminated in 2010 when the temperature exemption for sleeper truck rest expires. Statewide 

emission reductions are estimated to be 1610 tons, 45 tons and 30 tons per year for NOx, VOC 

and PM2.5, respectively. PADEP will also utilize enhanced enforcement to obtain additional 

emission reductions.

Significant additional reductions in NOx, direct PM2.5 and SO2 emissions will occur in 

emissions from highway and nonmobile sources after 2009. In addition, NOx controls for 

cement kilns and glass furnaces were approved by EPA on July 19, 2011 (76 FR 42258) and 

August 22, 2011 (76 FR 52283), respectively. Furthermore, PM2.5 control from the operation of 

outdoor wood-fired boilers was approved by EPA on September 20, 2011 (76 FR 58114). Sulfur 

limits for fuel oil (home heating oil and residential oil) are anticipated to be adopted later. 

Regulations to reduce VOC emissions are also in development, including controls on the 

manufacture and use of adhesives, primers and sealants and regulations incorporating the Control 

Technique Guidelines issued by EPA in 2006, 2007 and 2008. 

As required, these measures were fully adopted rules or control measures that were ready

to be implemented quickly upon failure of the area to attain, were in addition to those measures 

otherwise relied upon for attainment, had trigger mechanisms and a schedule for implementation, 

and were at the level of reductions equal to at least one year’s worth of reductions needed for 

attainment in the area. EPA finds that the measures submitted by Pennsylvania have satisfied 

the requirements for contingency purposes. 

EPA’s General Preamble interprets the control measure requirements of sections 

172(c)(9) and 182(c)(9) to allow states to implement measures before they are triggered (57 FR 

13498, 13511). EPA has previously approved a number of SIPs under this interpretation (66 FR 

15844, April 3, 1997; 62 FR 66279, December 18, 1997; 66 FR 30811, June 8, 2001; 66 FR 586, 

and 66 FR 634, January 3, 2001) and the Fifth Circuit has upheld EPA’s interpretation. 

Louisiana Environmental Action Network v. EPA, 382 F.3d 575 (Fifth Cir. 2004). It does not 
27

matter whether or not a specific contingency measure is already required by law, as long as the 

emissions reductions that will result from the contingency measure have not been relied upon in 

the attainment demonstration.

The contingency measures in Pennsylvania’s attainment demonstration (described above) 

that are already implemented and provide reductions in excess of those required by the 

attainment demonstration to attain the standards. The level of reductions provided is equal to at 

least one year’s worth of reductions needed for attainment in the Pennsylvania portion of the 

Philadelphia area. One year’s worth of reductions needed for attainment is determined by

dividing the emissions from base year levels that are needed for attainment by the number of 

years between the base year and the attainment year. (See PM2.5 Implementation Rule, page 

20643). Contingency measures are implemented in the event that the Philadelphia area fails to 

attain the standards by its attainment date. Although the Philadelphia area, as indicated above, 

met their attainment date of April 5, 2010 and thus is not required to implement contingency

measures, by relying on those measures that were already in place, Pennsylvania effectively

implemented their control measures in advance. 

VIII. Motor Vehicle Emission Budgets

The CAA requires Federal actions in nonattainment and maintenance areas to “conform 

to” the goals of SIPs. This means that such actions will not: (a) cause or contribute to violations 

of a NAAQS; (b) worsen the severity of an existing violation; or (c) delay timely attainment of 

any NAAQS. Actions involving Federal Highway Administration (FHWA) or Federal Transit 

Administration (FTA) funding or approval are subject to the transportation conformity rule (40 

CFR part 93, subpart A). Under this rule, metropolitan planning organizations (MPOs) in 

nonattainment and maintenance areas coordinate with State Air Quality and Transportation 

Agencies, EPA, and the FHWA and FTA to demonstrate that their long range transportation 

plans (“plans”) and transportation improvement programs (TIP) conform to applicable SIPs. 

This is typically determined by showing that estimated emissions from existing and planned 

highway and transit projects are less than or equal to the MVEBs contained in the SIP.

Section 176 (c) of the CAA requires Federal actions in nonattainment and maintenance 

areas to “conform to” the goals of SIPs. This means that such actions will not: cause or 

contribute to violations of a NAAQS, worsen the severity of an existing violation, or delay timely

attainment of any NAAQS. Actions involving Federal Highway Administration (FHWA) or 

Federal Transit Administration (FTA) funding or approval are subject to the transportation 

conformity rule (40 CFR part 93, subpart A). Under this rule, metropolitan planning 

organizations (MPOs) in nonattainment and maintenance areas coordinate with State Air Quality

and Transportation Agencies, EPA, and the FHWA and FTA to demonstrate that their long range 

transportation plans (“plans”) and transportation improvement programs (TIP) conform to 

applicable SIPs. This is typically determined by showing that estimated emissions from existing 

and planned highway and transit projects are less than or equal to the MVEBs contained in the 
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SIP.

The MVEBs for the 2009 attainment year are based on the projected 2009 on-road motor 

vehicle source emissions, accounting for the emission reductions from on-road vehicle source 

control measures, including transportation control measures and vehicle technology, fuel or 

maintenance-based measures. MVEBs for 2009 attainment year for the Pennsylvania portion of 

the Philadelphia area are 699 tons per year for PM2.5-direct and 36,318 tons per year for NOx as 

shown in Table 8. More detailed information can be found in the TSD entitled, “Adequacy

Findings for Motor Vehicle Emissions Budgets in the Attainment Demonstration for the 

Pennsylvania Portion of the Philadelphia-Wilmington-New Jersey City PM2.5 NAAQS 

Nonattainment Area,” dated October 6, 2011.

Table 8. Motor Vehicle Emission Budgets

2009 PM2.5 NOx

Tons per year 699 36318

For MVEBs to be approvable, they must meet, at a minimum, EPA’s adequacy criteria 

(40 CFR 93.118(e)(4)). The MVEBs for the Pennsylvania portion of the Philadelphia area PM2.5 

attainment plan are being posted to EPA’s conformity website concurrently with the notice of 

proposed rulemaking (NPR). The public comment period will end at the same time as the public 

comment period for the NPR. In this case, EPA is concurrently processing the action on the 

attainment plan and the adequacy process for the MVEBs contained therein. In the NPR, EPA is 

proposing to find the MVEBs adequate, and also proposing to approve the MVEBs as part of the 

attainment plan. The MVEBs cannot be used for transportation conformity until the attainment 

plan and associated MVEBs are approved in a final Federal Register notice, or EPA otherwise 

finds the budgets adequate in a separate action following the comment period. Our action on the 

Pennsylvania portion of the Philadelphia area MVEBs will also be announced on EPA’s 

conformity website: http://www.epa.gov/otaq/stateresources/transconf/index.htm, (once there, 

click on “Adequacy Review of SIP Submissions).

The budgets that Pennsylvania submitted were calculated using the MOBILE6.2 motor 

vehicle emissions model. EPA is proposing to approve the inventory and the conformity budgets 

calculated using this model because this model was the most current model available at the time 

Pennsylvania was performing its analysis. Separate from the NPR, EPA has issued an updated 

motor vehicle emissions model known as the Motor Vehicle Emission Simulator or MOVES. In 

its announcement of this model, EPA established a grace period for continued use of 

MOBILE6.2 in transportation conformity determinations for transportation plans and TIPs, after 

which states and MPOs (other than California) must use MOVES for transportation plan and TIP 

conformity determinations. This grace period will expire in March 2012 (or March 2013 once

the extension becomes official). 

Additional information on the use of MOVES in SIPs and conformity determinations can 
29

be found in the December 2009, “Policy Guidance on the Use of MOVES2010 for State 

Implementation Plan Development, Transportation Conformity, and Other Purposes.” This 

guidance document is available at: http://www.epa.gov/otaq/models/moves/420b09046.pdf.

During the conformity grace period, the State and MPO(s) should use the interagency

consultation process to examine how MOVES2010a will impact their future transportation plan 

and TIP conformity determinations, including regional emissions analyses. For example, an 

increase in emission estimates due to the use of MOVES2010a may affect an area’s ability to 

demonstrate conformity for its transportation plan and/or TIP. Therefore, state and local planners 

should carefully consider whether the SIP and motor vehicle emissions budget(s) should be 

revised with MOVES2010a or if transportation plans and TIPs should be revised before the end 

of the conformity grace period, since doing so may be necessary to ensure conformity

determinations in the future.

We would expect that states and MPOs would work closely with EPA and the local 

FHWA and FTA offices to determine an appropriate course of action to address this type of 

situation if it is expected to occur. If Pennsylvania chooses to revise its PM2.5 attainment plan, it 

should consult Question 7 of the December 2009, “Policy Guidance on the Use of MOVES2010 

for State Implementation Plan Development, Transportation Conformity, and Other Purposes,”

for information on requirements related to such revisions.

D. SUMMARY AND RECOMMENDATIONS:

The PM2.5 attainment plan for the Pennsylvania portion of the Philadelphia area meets the 

requirements of the CAA as described in the Clean Air Fine Particle Implementation Rule (April 

25, 2007, 72 FR 20586). The attainment plan supports a determination that the Pennsylvania

portion of the Philadelphia area attains the 1997 annual PM2.5 NAAQS. The attainment plan 

includes an attainment demonstration, MVEBs used for transportation conformity purposes,

RACM/RACT analysis, contingency measures, and the 2002 base year emission inventories. 

Therefore, we recommend approval of the PM2.5 attainment plan for the Pennsylvania portion of 

the Philadelphia area.