UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: February 6, 2013

SUBJECT: Technical Support Document for the Motor Vehicle Emissions Budgets for the

Pennsylvania Counties in the Philadelphia-Wilmington, PA-NJ-DE 1997 Fine 

Particulate Matter Nonattainment Area 

FROM: Asrah Khadr, Environmental Engineer /s/

Office of Air Program Planning 

TO: File

THRU: Cristina Fernandez, Associate Director /s/

Office of Air Program Planning

A. BACKGROUND: 

On November 6, 2012, the Pennsylvania Department of Environmental Protection (DEP) 

submitted for parallel processing a revision to the Commonwealth of Pennsylvania’s 

(Pennsylvania) State Implementation Plan (SIP). On January 31, 2013, Pennsylvania DEP 

submitted its formal, final SIP revision to update the SIP-approved Motor Vehicle Emissions 

Budgets (MVEBs) for the Philadelphia Area. The Region is now acting on the final SIP 

revision. The SIP revision consists of updated MVEBs for nitrogen oxides (NOx) and fine 

particulate matter (PM2.5) for the 1997 PM2.5 National Ambient Air Quality Standard (NAAQS). 

The updated budgets were calculated using the Environmental Protection Agency’s (EPA) Motor 

Vehicle Emission Simulator model (MOVES2010a). The intention of the revised SIP is to 

replace the approved MOBILE6.2-based MVEBs with budgets based on MOVES2010a and to 

ensure that the SIP revision still provides for attainment of the 1997 PM2.5 NAAQS. 

On July 18, 1997, EPA established the 1997 PM2.5 NAAQS. On January 5, 2005 (70 FR 943), 

Philadelphia, Bucks, Delaware, Chester and Montgomery Counties were designated as 

nonattainment for the 1997 PM2.5 NAAQS as a part of the Philadelphia Area. On November 29, 

2009 (74 FR 62251), EPA published a finding of failure to submit a SIP that demonstrates 

attainment of the 1997 PM2.5 NAAQS for the Philadelphia Area. On April 12, 2010, 

Pennsylvania submitted a SIP that demonstrates attainment of the 1997 PM2.5 NAAQS. 

Pennsylvania submitted an amendment to its April 12, 2010 submittal relating to Reasonably

Available Control Technology (RACT) on August 3, 2012. On August 28, 2012 (77 FR 51930), 

EPA published a final rulemaking notice (FRN) approving the April 12, 2010 SIP revision, as 

amended on August 3, 2012. Included in the April 12, 2010 SIP revision as revised August 3, 

2012, are the MVEBs for NOx and PM2.5 for the Philadelphia Area. 
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The MVEBs are a mobile source inventory to which an area’s transportation improvement 

program (TIP) and long range transportation plan must conform. Conformity to MVEBs in a SIP 

means that transportation activities will not produce new air quality violations, worsen existing 

violations, or delay timely attainment of the NAAQS or any required interim milestones. This 

January 31, 2013 SIP revision submittal provides updated MVEBs for NOx and PM2.5. The 

budgets were developed utilizing MOVES2010a. On March 2, 2010 (75 FR 9411), EPA 

published a notice of availability for the MOVES2010 model for use in SIP submissions and 

started a two year grace period for the use of MOVES2010 for transportation conformity

purposes. The two year grace period was scheduled to end on March 2, 2012. On February 27, 

2012 (77 FR 11394), EPA published a final rule extending the grace period another year to 

March 2, 2013 to ensure adequate time for affected parties to adopt the model. On September 8, 

2010, EPA released MOVES2010a, which is a minor update to MOVES2010. Pennsylvania 

utilized MOVES2010a in its January 31, 2013 SIP revision. MOVES2010a was used in order to 

ensure that the nonattainment area can demonstrate transportation conformity using 

MOVES2010a once the 3-year conformity grace period expires. Pennsylvania updated their 

2002 base year inventory and 2009 MVEBs that were approved on August 28, 2012 with the use 

of MOVES2010a. The budgets were previously developed with the use of the Highway Mobile 

Source Emission Factor Model (MOBILE6.2). 

MOBILE6.2 is a motor vehicle emissions factor model that was utilized for SIPs and 

transportation conformity for PM2.5 and course particulate matter (PM10) standards. MOBILE6.2 

was made available for use in SIPs and transportation conformity purposes on May 19, 2004 (69 

FR 28830). MOBILE6.2 was merely an update to MOBILE6 that added the ability for the 

program to estimate direct exhaust and brake and tire wear particulate matter emission factors as 

well as exhaust emission factors for particulate matter precursors. 

MOVES2010 improves upon MOBILE6.2 in many aspects. MOVES2010 utilizes a plethora of 

vehicle data that has been made available since the release of MOBILE6.2; this vehicle data 

includes emissions data for different kinds of vehicles. The new data has allowed EPA to better 

understand on-road mobile source emissions and their contribution to emissions inventories as 

well as how effective different control strategies are. The MOVES2010 model offers more 

flexibility because the program has a database design that allows easier organization of input and 

output files and data. The database design of the MOVES2010 model allows much easier update 

of input data upon the release of new data. MOVES2010 also accounts for temperature and 

speed variations and allows the model to run at a higher resolution which allows for the input of 

more activity data. 

Under Section 176(c) of the Clean Air Act (CAA), any federal action is required to conform to 

the applicable SIP. A part of this requirement for conformity is transportation conformity. 

Transportation conformity requires that any federally funded transportation plan, program or 

project conform to the applicable SIP for the transportation-related criteria pollutants (ozone, 

carbon monoxide, PM2.5, PM10, and nitrogen dioxide). The transportation conformity rules can 

be found at 40 CFR 93, Subpart A. One of the requirements found under 40 CFR 93, Subpart A 

is that any transportation plan, TIP or project not in a conforming TIP must conform to the 

MVEBs in the applicable SIP. In order for the MVEBs in a SIP to be used to determine 
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conformity of a transportation plan, TIP or project, the MVEBs must be either approved or 

deemed adequate. In this case, the budgets must be approved because this SIP revision is 

revising already approved budgets. However, in reviewing such a submitted SIP it remains 

useful to apply the criteria used to make an adequacy finding. The requirements for adequacy

are set forth in 40 CFR 93.118(e)(4)(i)-(vi). The criteria for adequacy and how they are met by

the Pennsylvania submittal are found below in Table 1: Adequacy Criteria. The plan was 

properly submitted by Pennsylvania, the attainment plan was approved on August 28, 2012 (77 

FR 51930), and the MVEBs were clearly and accurately identified and quantified. 

Table 1: Adequacy Criteria

Criterion Submittal

(i) The submitted control strategy implementation plan 

revision or maintenance plan was endorsed by the 

Governor (or his or her designee) and was subject to a 

State public hearing;

 Letter addressed to Shawn M. Garvin, 

Regional Administrator, EPA Region 

III from Michael L. Krancer, 

Secretary, Pennsylvania DEP

 Public hearing documents were 

submitted 

(ii) Before the control strategy implementation plan or 

maintenance plan was submitted to EPA, consultation 

among federal, State, and local agencies occurred; full 

implementation plan documentation was provided to 

EPA; and EPA's stated concerns, if any, were addressed;

 N/A, this revision does not 

accompany a control strategy 

implementation plan or maintenance 

plan

(iii) The motor vehicle emissions budget(s) is clearly 

identified and precisely quantified;

 Appendix A-2 of the submittal 

provides detailed emission summary 

tables

(iv) The motor vehicle emissions budget(s), when 

considered together with all other emissions sources, is 

consistent with applicable requirements for reasonable 

further progress, attainment, or maintenance (whichever 

is relevant to the given implementation plan 

submission);

 Attainment plan for the Philadelphia 

Area was already approved on August 

28, 2012 (77 FR 51930), and this SIP 

revision shows that there have been 

no changes to any assumptions 

utilized in that attainment plan 

 On May 16, 2012 (77 FR 28782), the 

Region published an FR notice 

indicating that the Philadelphia Area 

attained the 1997 PM2.5 NAAQS by 

the applicable attainment date of April 

5, 2010. The Philadelphia Area 

continues to meet the 1997 PM2.5 

NAAQS

(v) The motor vehicle emissions budget(s) is consistent 

with and clearly related to the emissions inventory and 

the control measures in the submitted control strategy 

implementation plan revision or maintenance plan; and

 The SIP revision shows no change in 

any assumptions utilized in the 

attainment plan, where the original 

budgets were submitted. None of the 

control measures have changed.
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(vi) Revisions to previously submitted control strategy 

implementation plans or maintenance plans explain and 

document any changes to previously submitted budgets 

and control measures; impacts on point and area source 

emissions; any changes to established safety margins 

(see § 93.101 for definition); and reasons for the changes 

(including the basis for any changes related to emission 

factors or estimates of vehicle miles traveled).

 Changes in MVEBs are clearly 

documented and explained in the 

submittal. The higher emissions are 

due to the use of MOVES2010a 

which is a more accurate emissions 

model and is based on more recent 

data on vehicle emissions than 

MOBILE6.2 

B. STATE SUBMITTAL:

On January 31, 2013, Pennsylvania DEP submitted a SIP revision which included an update for 

the MVEBs for PM2.5 and NOx for the year 2009. On January 31, 2013, Pennsylvania DEP 

submitted its formal, final SIP revision to update the SIP-approved MVEBs for the Philadelphia 

Area. The MVEBs were produced using the MOVES2010a model. The MVEBs were developed 

with guidance from the following EPA guidance documents: Policy Guidance on the Use of 

MOVES2010 for SIP Development, Transportation Conformity, and Other Purposes and 

Technical Guidance on the Use of MOVES2010 for Emission Inventory Preparation in State 

Implementation Plans and Transportation Conformity. 

I. Methodology for Developing Data for Use in MOVES2010a

Pennsylvania DEP utilized MOVES2010a to provide emissions rates for emissions of PM2.5 as 

well as for precursor emissions. The precursors for PM2.5 include volatile organic compounds 

(VOCs), nitrogen oxides (NOx), sulfur dioxide (SO2) and ammonia (NH3). PPSUITE is a 

program that was utilized for the processing of highway information and to provide input files 

that are usable by the MOVES2010a model. PPSUITE was run utilizing CENTRAL; 

CENTRAL is a program that provides a process for the proper function of PPSUITE and 

MOVES2010a. The approved attainment demonstration is based on NOx being the only 

significant PM2.5 precursor from on-road sources; therefore, the attainment demonstration and 

this SIP revision establish budgets for NOx. But Pennsylvania provided estimates for other 

insignificant precursors and carbon monoxide (CO) and PM10 as a courtesy. 

In PPSUITE, the Pennsylvania Department of Transportation (PennDOT) Roadway Management 

System (RMS) data was utilized for vehicle miles traveled (VMT) estimates. The data available 

for the year 2008 was developed with respect to traffic signals. Additionally, the highway data 

also included the average annual daily traffic (AADT) which includes vehicle volumes on state 

roadways; also, to include local roadway VMT, the VMT yielded by PennDOT’s RMS was 

adjusted. As shown in Table 2: VMT Growth, VMT actually decreased in all of the counties in 

the PA portion of the Philadelphia area from the 2002 base year to 2008. 
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Table 2: VMT Growth

Year

Growth from 

2002 

Annual Growth Rate from 

2002

Bucks County

2002 N/A N/A

2009 -2.0% -0.3%

Chester County

2002 N/A N/A

2009 -3.3% -0.5

Delaware County

2002 N/A N/A

2009 -1.30% -0.20%

Montgomery County

2002 N/A N/A

2009 -2.80% -0.40%

Philadelphia County

2002 N/A N/A

2009 -0.70% -0.10%

Before the VMT data is utilized in MOVES2010a, it is split for seasonal adjustments. The 

seasonal factors utilized for data adjustments were obtained from PennDOT’s 2002 Pennsylvania 

Traffic Data report and the 2008 Pennsylvania Traffic Data report. Both documents were 

developed by PennDOT’s Bureau of Planning and Research (BPR). Seasonal and daily factors 

provided by BPR were developed with respect to statistical analyses of 2002 and 2008 traffic 

counts that were obtained by automatic traffic recorders (ATR) which are located within the 

pavement and are dispersed throughout roadways in Pennsylvania. 

PPSUITE also estimates hourly speed distributions based on AADT. The daily RMS volumes 

are converted to hourly volumes by the use of vehicle pattern data which allows the variations in 

traffic volumes to be determined with respect to time. The vehicle pattern data is obtained from 

PennDOT’s 2002 Pennsylvania Traffic Data report and 2008 Pennsylvania Traffic Data report. 

Vehicle population was estimated in several ways. Registration data for the years 2002 and 2008 

was utilized to determine the vehicle population for light duty vehicles and school buses. The 

data was then disaggregated by MOVES2010a and sectioned into source types by using 

population data. Data from PennDOT and the National Transit Database (NTD) was utilized for 

the estimation of the transit bus population. The vehicle population of other heavy duty vehicles 

was estimated by PPSUITE via the analysis of annual VMT for each source type and ratios of 

VMT for the source type populations that are provided by MOVES2010a. For the estimation of 

the 2009 vehicle fleet composition, the 2008 vehicle fleet composition was utilized and projected 

to 2009 by utilizing the highest growth rate for population and households while limiting the 

growth assumption such that it did not cause an exceedance of VMT with respect to VMT 

growth assumptions. 
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VMT by source type was also utilized as a data input. The total VMT was taken apart by 

MOVES2010a and was then aggregated again into one of the 13 vehicle source types. The 

vehicle source type was calculated for each county and functional class via the use of the 2002 

and 2008 RMS truck percentages, the 2008 PennDOT and NTD transit data and 2008 school bus 

registration data. The remaining VMT distribution was determined via MOVES2010a . 

Each of the vehicle source types were also broken down with respect to the vehicle age 

distribution for each source type. The distribution provides different percentages with respect to 

the age of the vehicle for each vehicle source type. The 2002 vehicle age distribution was 

utilized for the 2002 MVEBs, while the 2010 vehicle age distribution was utilized for the 2009 

MVEBs since 2010 registration data revealed that the fleet was significantly older than was 

previously thought. Data for light duty vehicles was utilized for local inputs. MOVES2010a 

default data was utilized for heavy duty vehicles. 

MOVES2010a also includes input parameters for inspection and maintenance (I/M) programs. 

The defaults for an I/M program in MOVES2010a were modified to accurately represent the 

different I/M programs in different counties. The I/M program for the Philadelphia Area covers 

the following counties: Bucks, Chester, Delaware, Philadelphia, and Montgomery Counties. 

Fuel supply data was provided by default data in MOVES2010a which was later updated by 

local volumetric fuel data. MOVES2010a was utilized for the remaining fuel supply data. The 

updated data included utilizing 8.7 Reid Vapor Pressure (RVP) for the summer months, 35% of 

the market share being conventional gasoline and 68% of the market share being composed of 

10% ethanol for the year 2009, as well as the use of conventional gasoline for use throughout 

2002. 

The meteorology data utilized included data retrieved from WeatherBank Inc. MOVES2010a 

requires daily relative humidity and temperature data for entry into the model for annual analysis 

of emissions. The data retrieved from WeatherBank Inc. was converted from minimum and 

maximum daily temperatures to hourly minimum and maximum hourly temperatures by EPA’s 

data converters. 

Vehicle technology programs are also incorporated into MOVES2010a. The current federal 

program incorporated into the model is the National Low Emission Vehicle (NLEV) Program. 

The current state program for Pennsylvania incorporated into MOVES2010a is the Pennsylvania 

Clean Vehicles (PCV) Program. This program is included in the modeling efforts for all years 

after 2008. The PCV Program incorporated by reference the California Low Emission Vehicle 

Program (CA LEVII), therefore EPA provided input files to represent the CAL LEVII Program 

to be input into MOVES2010a.

II. Running MOVES2010a

As stated in Section I, the data utilized to run MOVES2010a is a mixture of local and national 

data. Local data is utilized for all inputs that have significant impact on the emissions rates that 

are calculated by MOVES2010a. The local data utilized as inputs for MOVES2010a is 
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categorized into five categories which include: traffic data, vehicle descriptions, fuel parameters, 

I/M programs, and environmental variables. The inputs for traffic data include vehicle type 

VMT, vehicle population, VMT fractions, road type distributions, and ramp fractions. The 

inputs for vehicle descriptions include vehicle type mix, vehicle age distribution, average speeds 

and hourly distributions of different vehicles. The inputs for fuel parameters include RVP, sulfur 

level, ethanol volume and refueling controls. The inputs for I/M programs include start and 

model years, the frequency of tests, test standards, source types, stringency of tests, the waiver 

rate, and compliance rates. The inputs for environmental variables include hourly temperatures 

and humidity. 

MOVES2010a inputs that were prepared by PPSUITE included vehicle type VMT, vehicle 

population, VMT fractions, average speed distributions, road type distribution and ramp 

fractions. These files were input into the MOVES2010a county data importer. Additional nonPPSUITE inputs included fuel and vehicle ages, as well as temperatures and I/M programs. The 

county data importer was run in batch mode. Running the county data importer converts input 

files into a MYSQL format which is accepted by MOVES2010a. Afterwards, a MOVES run 

specification file (.mrs) was created. This file includes options and different data locations for 

the execution of the model. MOVES2010a can be executed to provide an emissions rate or an 

emissions inventory. In this submittal, MOVES2010a was executed to provide an emissions 

inventory. The emissions estimates of direct PM2.5 and NOx produced for the years 2002 and 

2009 are provided in Table 3: Summary of MVEBs. This table also provides the comparison 

between the 2002 base year inventory and the 2009 MVEBs produced by MOVES2010a and 

MOBILE6.2. After reviewing this submittal, EPA concurs with Pennsylvania that even though 

the emissions results produced by MOVES2010a are greater than those previously calculated 

using MOBILE6.2. EPA’s review of the SIP revision indicates these higher emissions result 

from improvements in the MOVES model rather than from unanticipated growth or changes in 

control measures. The MOVES results are more accurate estimates of the emissions that actually

occurred in 2002 and 2009, rather than an indication that emissions are increasing. More 

importantly, the Philadelphia Area attained the 1997 PM2.5 NAAQS in 2009 and continues to 

attain that NAAQS now with emissions that are being released from all sources. EPA 

determined on May 16, 2012 (77 FR 28782), that the Philadelphia Area attained the 1997 PM2.5 

NAAQS by the applicable attainment date, April 5, 2010, in accordance with section 179(c)(2) 

of the CAA. The design values for the Philadelphia Area for the years 2007-2009, 2008-2010, 

and 2009-2011 are as follows: 13.7 micrograms per meter cubed (μg/m3), 13.8 μg/m3, and 13.7 

μg/m3. All of the design values are under the 1997 PM2.5 NAAQS which is 15 μg/m3. Also 

preliminary 2012 data shows that the Philadelphia Area continues to attain the standard. 

Therefore, EPA finds this update to the MVEBs does not interfere with the Philadelphia Area’s 

ability to continue to attain the1997 PM2.5 NAAQS.

Table 3: Summary of MVEBs

Model MOBILE6.2 MOVES2010a

Year 2002 2009 2002 2009

PM2.5 (tpy) 1032.8 699.1 2,904.60 1,907.5

NOx (tpy) 63,475.9 36,317.7 90,879.00 57,218.3
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C. EPA EVALUATION AND CONCLUSION:

EPA thoroughly evaluated the submittal made by Pennsylvania through Pennsylvania DEP. Our 

detailed review has led us to conclude that the development methodology of the MVEBs is 

consistent with applicable guidance documents intended to guide the development of on-road 

inventories and MVEBs. We have also reviewed the available air quality data from the 

Philadelphia area. The area attained the 1997 PM2.5 NAAQS by the attainment date of April 5, 

2010 and continues to attain the 1997 PM2.5 NAAQS now. We also reviewed the MVEBs using 

the adequacy criteria set forth in 40 CFR 93.118(e)(4)(i)-(vi), and as documented above we 

found that the budgets meet all of the adequacy criteria. Based on the results of our in depth 

review of the SIP revision, the area’s continued attainment of the 1997 PM2.5 NAAQS and the 

results of our review of the MVEBs using the adequacy criteria in the transportation conformity

rule, EPA is proposing to approve the SIP revision.