UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION III 

1650 Arch Street 

Philadelphia, Pennsylvania 19103 

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

Vehicle Emissions for the Redesignation Request and Maintenance Plan for the 

West Virginia Portion of the Parkersburg-Marietta, WV -OH 1997 Fine Particulate 

Matter (PM2.s) Nonattainment Area 

FROM: Gregory Becoat ~ 1/ 31 l~ Environmental Scientist (3AP30) 

TO: Administrative Record for the Insignificance Findings for the Motor Vehicle 

Emissions for the Redesignation Request and Maintenance Plan for West Virginia 

Portion of the Parkersburg-Marietta, WV-OH 1997 PM2.s Nonattainment Area 

THRU: Donna Mastro, Acting Associate Director "~ tli fro.....A~ )![A .<1::::::::- r/~J~~ Office of Air Program Planning (3AP30) Vu IV 1 · ...-- V'\ 

I. Background 

The Clean Air Act (CAA) requires federal actions in nonattainment and maintenance areas to 

"conform to" the goals of State Implementation Plans (SIP). See, e.g., CAA section 176. This 

means that such actions will not cause or contribute to violations of a national ambient air quality 

standard (NAAQS); worsen the severity of an existing violation; or delay timely attainment of 

any NAAQS or any interim milestone. 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, Environmental Protection Agency (EPA), FHW A, and FT A 

to demonstrate that their metropolitan transportation 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 systems are less than or equal 

to the motor vehicle emissions budgets (MVEBs) contained in a SIP. 

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

40 CFR 93 .118( e)( 4 ). In certain instances, the Transportation Conformity Rule allows areas to 

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forgo establishment of a MVEB where it is demonstrated that the regional motor vehicle 

emissions for a particular pollutant or precursor are an insignificant contributor to the air quality 

problem in an area. The general criteria for insignificance determinations can be found in 40 

CFR 93.1 09(f). Insignificance determinations are based on a number of factors, including the 

percentage of motor vehicle emissions in the context of the total SIP inventory; the current state 

of air quality as determined by monitoring data for the relevant NAAQS; the absence of SIP 

motor vehicle control measures; and the historical trends and future projections ofthe growth of 

motor vehicle emissions. EPA's rationale for providing for insignificance determinations is 

described in the July 1, 2004, revision to the Transportation Conformity Rule at 69 FR 40004. 

Specifically, the rationale is explained on page 40061 under the subsection XXIII.B. entitled, 

"Areas With Insignificant Motor Vehicle Emissions." Any insignificance determination under 

review ofEPA is subject to the adequacy and approval process for EPA's action on the SIP. 

II. Administrative Requirements for Making Insignificance Findings 

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

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

procedures listed in the January 2008 Conformity Regulations contained in 40 CFR 9·3.102(b)-

"Geographical applicability" and 40 CFR 93 .118(f) - "Adequacy review process for 

implementation plan submissions." 

On March 8, 2012, the State of West Virginia formally submitted a Redesignation Request and 

Maintenance Plan for West Virginia Portion of the Parkersburg-Marietta, WV-OH 1997 PM2.5 

Nonattainment Area (hereafter the Redesignation Request and Maintenance Plan). The SIP 

included a request for a finding of insignificance by EPA for motor vehicle emissions for 

nitrogen oxides (NOx), direct particulate matter (PM), and sulfur dioxide (S02). 

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

in the Redesignation Request and Maintenance Plan for the West Virginia Portion of the 

Parkersburg-Marietta, WV-OH 1997 PM2.5 Nonattainment Area Submitted By The West 

Virginia Department of Environmental Protection 

In this TSD, EPA is evaluating the West Virginia Department of Environmental Protection's 

request for an insignificance finding for motor vehicle emissions associated with the 

Redesignation Request and Maintenance Plan contained in the submittal. EPA is using the 

evaluation criteria detailed in the Transportation Conformity Rule, 40 CFR 93.102(b)(2)(iv), 

(b)(2)(v), and (b)(3) and 93.118(e)(4) and (e)(5). The evaluation is presented below. 

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Review of the Request for Insignificance Finding of Motor Vehicle Emissions in the 

Redesignation Request and Maintenance Plan for the West Virginia Portion of the 

Parkersbur~-Marietta, WV-OH PM2.s Nonattainment Area 

Transportation Conformity Rule Review Criteria 

40 CPR Part 93, Section 93 .118 

93.102(b)(2)(iv) Has the EPA and the State 

made a finding that NOx is 

an insignificant contributor 

to the direct mobile PM 

emissions or does the 

implementation plan fail to 

establish a NOx budget as 

part of the PM 2.s 

maintenance strategy? 

93.102(b)(2)(v) 

93.102(b)(3) 

Has the EPA or State made a 

finding that the precursors, 

Volatile Organic Compounds 

(VOCs), S02 or Ammonia 

{NH3) are a significant 

contributor to the mobile PM 

emissions or does the 

implementation plan 

submission establish a 

budget for VOCs, SOx or 

NH3 as part of a PM 2.s 

maintenance strategy? 

Has the EPA or the State 

made a finding that direct 

PM is a significant 

contributor to the PM mobile 

emissions or does the 

implementation plan 

establish a budget that 

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Was the Criterion Satisfied? If 

Yes, How was this Criteria 

Satisfied? 

The State has requested that NOx 

be found an insignificant 

contributor to the mobile PM 

emissions. This request is based 

on the State finding that Onroad 

mobile source NOx constitutes 

less than twelve percent of the 

area's total NOx emissions in the 

20 15 and 2022 horizon years due 

to continuing fleet turnover even 

with future vehicle miles traveled 

(VMT) growth included in the 

emission projections. EPA has 

also made a fmding that the 

transportation-related emissions of 

NOx within the nonattainment 

area are not a significant 

contributor to .the direct mobile 

PM·emissions. 

Neither EPA nor the State has 

made any findings that VOCs, 

S02, or NH3 is a significant 

contributor to the PM2.s mobile 

emissions, and therefore, it has 

not been included in the SIP. 

Onroad mobile source S02 

emissions constitute less than 

0.1% of the area's total so2 

emissions ·in the 2015 and 2022 

horizon years. 

The State has requested that direct 

PM be found an insignificant 

contributor to the mobile PM 

emissions. This request is based 

on the State fmding that Onroad 

mobile source PM2.s constitutes 

less than 2.1% of the area's total 
includes direct PM as part of PM2.s emissions in the 20 15 and 

a PM 2.5 maintenance 2022 horizon years due to 

strategy? 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 submitted 

plan endorsed by the Redesignation Request and 

Governor (or his or her Maintenance Plan was endorsed 

designee) and subject to a and submitted as a SIP revision by 

State public hearing? the Governor's designee, the 

Secretary of the West Virginia 

Department of Environmental 

Protection. A public hearing on 

the SIP proposal was held. 

Sec. 93.118(e)(4)(ii) Before the maintenance plan Yes. Consultation has occurred 

was submitted to EPA, did among all required Federal, State, 

consultation between federal, and local agencies. 

State and local agencies 

occur; was full 

implementation plan 

documentation provided to 

EPA, and was EPA's stated 

concerns, if any, addressed? 

Sec. 93.118(e)(4)(iii) Were the MVEBs clearly As there was a request for an 

identified and precisely insignificance finding, no MVEBs 

quantified? were identified in the SIP. 

Sec. 93.118(e)(4)(iv) Are the motor vehicle EPA believes that motor vehicle 

emissions, when considered emissions can be declared 

together with all other insignificant contributors because 

emission reductions, in comparing the motor vehicle 

consistent with applicable emissions to the overall emissions 

' requirements for inventory, the motor vehicle 

maintenance strategies? emissions comprise only a small 

portion of the over PM2.s 

emissions for the nonattainment 

area and are projected to continue 

to significantly decline due to fleet 

turnover. 

Sec. 93.118(e)(4)(v) Are the motor vehicle EPA believes that the motor 

emissions consistent with vehicle emissions have clearly 

and clearly related to the related to the emissions inventory 

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emissions inventory and the and control measures in the SIP 

control measures in the Plan? submittal. 

Sec. 93.118(e)(4)(vi) Revisions to previously There are no revisions to the 

submitted maintenance plan: maintenance plan because this is 

explain and document any the initial redesignation request, 

changes to previously along with the associated 

submitted budgets and maintenance plan for West 

control measures; impacts on Virginia Portion of the 

point and area source Parkersburg-Marietta, WV-OH 

emissions; any changes to Area. 

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 the 

review public comments and SIP related to the proposed 

the State's responses to those insignificance finding request. 

comments with the submitted 

control strategy SIP? 

IV. Findings 

Based upon our review and evaluation of the motor vehicle emissions contained in the West 

Virginia Redesignation Request and Maintenance Plan for the West Virginia Portion of the 

Parkersburg-Marietta, WV-OH 1997 PM2.s Nonattainment Area, EPA finds that the SIP 

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

NOx, PM2.5, and S02 contribution from motor vehicles. Weighing all the factors for an 

insignificance finding, particularly the minor contribution of mobile source PM2.s and S02, EPA 

has determined that the PM2.s and S02 contribution from motor vehicle emissions to the annual 

PM2.5 pollution for the West Virginia portion of the Nonattainment Area are insignificant. With 

respect to transportation conformity, the larger NOx contribution ofless than twelve and a half 

percent of the area's total NOx emissions in the 2015 and 2022 horizon years requires further 

justification to request an insignificant finding. 40 CFR 93.1 09(±) bases insignificance on 

emission percentages, emission trends, and the effectiveness of the pollutant in forming PM. For 

the Parkersburg-Marietta area, there is a significant emission decrease projected for the highway 

sector and total emissions source inventory in years 2008, 2015, and 2022. Given the relatively 

small contribution of the highway mobile emissions to the total SIP inventory, highway mobile 

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emissions are not likely to contribute significantly to local PM2.5• Additionally, NOx reductions 

are significantly less effective in reducing PM concentrations than are reductions in direct PM 

and S02. Consequently, NOx percentage emission contribution may be higher than direct PM 

and S02 without adversely affecting air quality. Based on the analysis of local historical trends 

and growth patterns in order to develop the long range transportation plan and transportation 

improvement program for transportation conformity purposes, EPA has no reason to expect 

highway motor vehicle emissions growth to lead to a violation of the annual PM2.s standard. 

Although vehicle miles traveled increases over time, NOx emissions are projected to decrease 

dramatically from 4505.4 tons/year in 2002 to 665.7 tons/year in 2030. This demonstrates that 

highway emissions will remain insignificant in the future. Upon review of the further 

justification for requesting an insignificant finding for NOx, EPA has determined that NOx 

contribution from motdr vehicle emissions to the annual PM2.

5 pollution for the West Virginia 

portion of the N onattainment Area is insignificant. 

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