UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION III 

1650 Arch Street 

Philadelphia, Pennsylvania 19103 

DATE: August 27,2015 

SUBJECT: Technical Support Document (TSD)- Insignificance Findings for the Motor 

Vehicle Emissions for the Liberty-Clairton, Pennsylvania (P A) 1997 and 2006 Fine 

Particulate Matter (PM2.s) National Ambient Air Quality Standards (NAAQS) 

Nonattainment Area 

FROM: 

TO: 

THRU: 

Administrative Record for the Insignificance Findings for the Motor Vehicle 

Emissions for the Liberty-Clairton, P A 1997 and 2006 PM2.s NAAQS 

Nonattainmen~ Area \') 

/1~-p;_/~ f~.t7 /tS 

Cristina Fernandez, Associate Director 

Office of Air Program Planning (3AP30) 

I. Background 

On June 21, 2013, the Commonwealth of Pennsylvania Department of Environmental Protection 

(PADEP) submitted, on behalf of Allegheny County, a formal revision to its State 

Implementation Plan (SIP). The SIP revision consisted of the 2006 24-hour PM2.s NAAQS 

attainment plan for the Liberty-Clairton Area, which included among other things, an attainment 

demonstration, a 2007 base year emissions inventory, a reasonably available control measures 

(RACM) analysis, and a description of contingency measures. On July 31, 2014, P ADEP 

formally submitted a supplement to the attainment demonstration for the 2006 PM2.s NAAQS for 

the Liberty-Clairton Area in order to include a request for findings of insignificance by 

Environmental Protection Agency (EPA) for motor vehicle emissions for nitrogen oxides (NOx) 

and direct PM2.s. Using emissions inventories and modeling already included as part of the June 

21, 2013 SIP submittal, the supplemental SIP revision demonstrates that motor vehicle emissions 

for direct PM2.s and NOx are insignificant contributors to the air quality problem in the Liberty 

Clairton Area for both the 1997 and 2006 PM2.s NAAQS. 

Transportation conformity is required under section 176(c) ofthe Clean Air Act (CAA) to ensure 

that federally supported highway, transit projects, and other activities are consistent with 
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II. Administrative Requirements for Making Adequacy and Insignificance Findings 

EPA has followed the process for reviewing the submitted SIP and determining if an 

insignificance finding for motor vehicle emissions is warranted in accordance with the 

procedures listed in the January 2008 Conformity Regulations contained in 40 CFR 93.102(b)-

"Geographical applicability," which applies to all nonattainment and maintenance areas for 

transportation-related criteria pollutants for which the area is designated nonattainment or has a 

maintenance plan, and 40 CFR 93.118(f)- "Adequacy review process for implementation plan 

submissions," which describes the procedures for reviewing the adequacy of an implementation 

plan submittal. Along with a direct final rule notice (DFRN), EPA will be issuing a short notice 

of proposed rulemaking (NPR) for a 30-day public comment period soliciting public comment 

for the approvability of the Commonwealth of Pennsylvania's SIP submission. During this time, 

the public will have the opportunity to comment on the adequacy/approvability of the 

insignificance findings in the SIP revision. If EPA receives such comments, it will publish a 

timely withdrawal of the DFRN in the Federal Register and inform the public that the rule will 

not take effect, which includes the adequate and approved insignificance findings for both the 

1997 and 2006 PM2.s NAAQS. 

III. Review of the Submitted Modeling Utilizing the Motor Vehicle Emission Simulator 

(MOVES2010) 

The highway mobile source emission inventory was developed using available travel data and 

EPA's MOVES2010a emission model. To utilize the MOVES2010a model, several different 

models were used to provide the necessary inputs into MOVES20 1 Oa. One of the models, 

PPSUITE, was utilized to provide inputs as well as to post-process the output files from 

MOVES2010a. 

The appropriate traffic related inputs which were processed by PPSUITE were input into 

MOVES2010a. Additional traffic related inputs as well as non-traffic related inputs were 

provided as well. The data was input into MOVES2010a via the county data manager. The 

county data manager is a function of the MOVES2010a model which allows county specific data 

inputs to be converted into a usable form by MOVES2010a. At that point a Run Specification 

(RunSpec ), which is a function of MOVES20 1 Oa that allows the user to input necessary 

parameters into the model, was created and run in batch mode. The outputs were provided as an 

inventory because vehicle miles traveled (VMT) and vehicle population were provided to 

MOVES2010a. 

EPA reviewed the modeling methodology utilized by PADEP and all modeling related 

information to produce the motor vehicle emissions inventory for years 2007 and 2014. EPA 

found that all necessary and required modeling procedures were followed in the production of the 

2007 and 2014 motor vehicle emissions inventory which were produced using MOVES2010a. 

IV. Evaluation of the Request for an Insignificance Finding for Motor Vehicle Emissions 

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(VOCs), sulfur dioxide (S02) PM2.s mobile emissions. The 

or Ammonia (NH3) are a June 21, 2013 SIP submittal 

significant contributor to the does not rely on reductions of 

mobile PM emissions or does VOCs or NH3 from any 

the implementation plan sources in the area. The SIP 

submission establish a submittal does rely on so2 

budget for VOCs, S02 or emissions reductions from 

NH3 as part of the PM2.s point sources; however, it 

attainment demonstration? does not rely on reductions 

from onroad S02 sources, 

which represented less than 

two tenths of one percent 

(<0.2%) ofthe area's total 

S02 emissions in the 2007 

and 2014 projected emissions. 

Therefore, MVEBs were not 

established for these 

precursors. 

93.1 02(b )(3) Has the EPA or the The Commonwealth has 

Commonwealth made a requested that direct PM be 

finding that direct PM is a found an insignificant 

significant contributor to the contributor to the mobile PM 

PM mobile emissions or does emissions. This request is 

the implementation plan based on the Commonwealth's 

establish a budget that finding that onroad mobile 

includes direct PM as part of source PM2.s constitutes less 

the PM2.s attainment than one percent (<1%) ofthe 

demonstration? area's total 2007 PM2.s 

emissions and the area's total 

projected 2014 PM2.s 

emissions due to continuing 

, fleet turnover even with future 

VMT growth included in the 

emission projections. 

Sec. 93.118(e)(4)(i) Was the submitted revised Yes. The SIP was endorsed 

plan endorsed by the and submitted by the 

Governor (or his or her Governor's designee, E. 

designee) and subject to a Christopher Abruzzo, the 

State public hearing? Secretary of the Pennsylvania 

Department of Environmental 

Protection. A public hearing 

on the SIP proposal was held 

on December 18,2013. 

Sec. 93.118(e)(4)(ii) Before the implementation Yes. Consultation has 

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emissions; any changes to 

established safety margins 

(see Sec. 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). 

Sec. 93.118(e)(5) Did they provide and we There were no comments on 

review public comments and the SIP related to the proposed 

the Commonwealth's insignificance finding request. 

responses to those comments 

with the submitted control 

strategy SIP? 

The requirements under 40 CFR 93.109(f) bases insignificance on emission percentages, 

emission trends, and the effectiveness of the pollutant in forming PM. Based upon our review 

and evaluation of the motor vehicle emissions contained in the Attainment Demonstration for the 

Liberty-Clairton, PA 1997 and 2006 PMz.s NAAQS Nonattainment Area, EPA finds that the SIP 

submittal meets the criteria in the transportation conformity rules for an insignificance finding for 

NOx and PMz.s contribution from motor vehicles. Weighing all the factors for an insignificance 

finding, particularly the minor contribution of mobile source PMz.s and NOx, EPA has 

determined that the PMz.s and NOx contribution from motor vehicle emissions to the PMz.s 

pollution for the Liberty-Clairton Nonattainment Area is insignificant. 

The first criteria requires that the motor vehicle emissions constitute a low percentage of the total 

SIP inventory. The submitted SIP satisfies this requirement. In particular, for the 2007 base 

year, the direct PM onroad mobile source constitutes 0.99% of the area's total PMz.s emissions 

and decreases in the later analysis year to 0.88% (2014). For the 2007 base year, the NOx onroad 

mobile source constitutes 4.9% of the area's total NOx emissions and decreases in the later 

analysis year to 3.07% (2014). The SIP submittal does rely on SOz emissions reductions from 

point sources; however, it does not rely on reductions from onroad SOz sources, which 

represented less than 0.2% of the total SOz inventory for the area. 

The second criteria requires that the current state of air quality is showing attainment based on 

monitoring data in the Liberty-Clairton Area. Currently, monitoring data shows that the LibertyClairton Area is attaining both the 1997 and 2006 PMz.s NAAQS. EPA has determined that the 

Liberty-Clairton Area attained the 1997 NAAQS by its attainment date, based on 2009-2011 

monitoring data (October 25,2013, 78 FR 63881). On July 10,2015 (80 FR 39696), EPA 

determined that the Liberty-Clairton Area had attained the 2006 24-hour PMz.s NAAQS, based 

on quality-assured and certified ambient air quality data for the 2012-2014 monitoring period. 

As a result, of EPA's determinations for both the 1997 and 2006 PMz.s NAAQS the second 

criteria has been satisfied by the Liberty-Clairton Area. 

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