Technical Support Document (TSD) for the RedesignationRequest and Maintenance Plan Forthe Pittsburgh-BeaverValley, PA 1997 PM2

.sNonattainment Area

Submitted December 2014 by the Pennsylvania Department ofEnvironmental Protection
TSD Prepared April 2015 by Jessica L. Fry Office ofAirMonitoring and Analysis, 3AP40 U.S. Environmental ProtectionAgency, Region 3 1650 Arch Street Philadelphia, Pennsylvania 19103

Reviewed by Alice H. Chow, AssociateDirector Office ofAir Monitoring and Analysis (3AP40)

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### I. Introduction
The purpose ofthis document is to provide atechnical summary ofthe Office ofAir Monitoring and Analysis (OAMA) review ofthe emissions inventories submitted with the Redesignation Request and Maintenance Plan for the Pittsburgh-Beaver Valley, PA 1997 PM2 s Nonattainment Area (NAA) by the Pennsylvania Department ofEnvironmental Protection (PADEP). TheNAA consists ofportions ofAllegheny, Armstrong, Greene, and Lawrence Counties as well as the whole counties ofBeaver, Butler, Washington, and Westmoreland in Pennsylvania. This review does not determine the approvability ofthe redesignation request or maintenance plan. Emissions inventories in a redesignation request are used to show permanent and enforceable emission reductions between the year the area was designated as a nonattainment area and the yearthe area came into attainment. In a maintenance plan, the emissions inventories are used to reflect the emissions during the time the area came into attainment and are thenprojectedto showthat the area will remain in attainment. On November 10, 2009 PADEP submitted a SIP revision to EPA which included a 2002 base year inventory to fulfill the 172(c)(3) Clean Air Act (CAA) requirement. EPA approved the base year inventory as a rule on December 13, 2012 (77 FR47115)

. Any questions pertaining to this technical summary should be directed to Alice H. Chow, Associate Director, Office ofAir Monitoring and Analysis, at 215-814-2144 or viaemail at chow.alice@epa.gov.


### II. Emissions Inventories for Redesignation Request
2005Nonattainment YearInventory
In a redesignation request, emissions inventories are used to support the State's claimthat the area has permanent and enforceable emissions reductions

. In order to do this, the state should estimate the percent reduction (from the year that was used to determine the design value for designation and classification) achieved from federal and state control measures; this is usually termed as the nonattainment or baseline year inventory. Forthe purpose ofthis plan, the year 2005 was used as the nonattainment year inventory. The 2005 nonattainment year inventory contains primary PM2

.semissions (including condensibles), S02,NOx,VOC, and NH3 emissions. This section will discuss the 2005 nonattainment year inventory that was used in the PittsburghBeaver Valley Redesignation Request and Maintenance Plan submitted by PADEP.
The NAA contains emissions from Beaver, Butler, Washington, and Westmoreland and the partial counties ofAllegheny, Armstrong, Greene, and Lawrence. PADEP used emissions from EPA's 2005 NEI for their point, nonpoint, and nonroad nonattainment year inventory. To calculate nonpoint and noruoad values for the partial counties included in the NAA, PADEP used county data apportioned by population for Allegheny, Armstrong, Greene, and Lawrence Counties ofwhich 98.47%, 3.96%, 4.06%, and 1.15% ofthepopulation, respectively is included in the NAA.
Forthe 2005 oruoad inventory PADEP linearly interpolated MOVES 2010 emissions estimates from 2002 and 2007. This was done in order to make a more direct comparison to the 2007 attainment year inventory which also used the MOVES 2010 model. EPA's 2005 NEIonroad emissions were generated using the MOBILE 6 model which was subsequently replaced by the MOVES model.
OAMA staffreviewed the files and the emissionresults providedby PADEP and found them to be acceptable.


### III. Emissions Inventories for Maintenance Plan


### 2007Attainment YearInventory andMaintenancePlan Base YearInventory
In a Maintenance Plan, states are required to submit an inventory used for the year of attainment, which is called the attainment year inventory and can also be referred to as the maintenance plan base year inventory. This inventory is used as the basis for the projected inventories that are used to showthe area will remain in attainment. The base year inventory submitted by PADEP contains primary PM2.s emissions (including condensibles), S02,NOx, VOC, and NH3 emissions. This section will discuss the 2007 emissions inventory that was used in the Pittsburgh-Beaver Valley Redesignation Request and Maintenance Plan in orderto fulfill the attainment year emissions inventory requirements.
Forthe 2007 base year inventory for the point, nonpoint, and nonroad categories, PADEP submitted the 2007 Version 3 Emissions Inventory developed through the Mid-Atlantic Regional AirManagementAssociation (MARAMA) regional planning process. Documentation ofthe development oftheinventory canbe found in Technical SupportDocument for the Development of the 2007Emission Inventoryfor the RegionalAir QualityModeling in the NortheastIMidAtlantic Region Version 3.3. January 23, 2012. To calculate nonpoint and nonroad values for the partial counties included in the NAA, PADEP used county data apportioned by population for Allegheny, Armstrong, Greene, and Lawrence Counties ofwhich 98.47%, 3.96%, 4.06%, and 1.15% ofthepopulation, respectively is included in the NAA.
The 2007 point source inventory contained emissions for EGU and non-EGU sources in the NAA. EPA guidance for emissions inventory development provides that actual emissions should be used for purposes ofthe base year inventory. PADEP developed their 2007 inventory by using emissions directly reported by the facilities. The PM emissions for the 2007 point source inventory were augmented using condensable emission factors developed for MARAMA in 2008. This was done to fill in any missing condensable PM emissions from facilities.
The nonpoint source emissions inventory for 2007 was developed using 2007 specific activity data along with EPA emission factors and the most recently available emission calculation methodologies. PADEP used 2008 NEI datato fill in any missing categories in the 2007 inventory. To calculate values for the partial counties included in the NAA, PADEP used county data apportioned by population.
For 2007 nonroad mobile sources, PADEP generated the emissions using EPA's NMIM2008 model. Since marine, air and rail/locomotive (MAR) emissions are not part ofthe NONROAD model, they were calculated separately outside ofthe NONROAD model. Aircraft emissions were developed using EPA's database to the support the 2008 NEI. PADEP usedrailroad emissions developed by the Eastern Regional Technical Advisory Committee (ERTAC)

. To calculate values for the the partial counties included in the NAA, PADEP used county data apportioned bypopulation.
The 2007 onroad mobile source inventory was developed using EPA's highway mobile source emissions model MOVES2010. PADEP used local activity to replace default inputs in the model where appropriate.
OAMA staffreviewed the files and the emission results provided by PADEP and found them to be acceptable.
2017and2025Projection EmissionInventories Projection inventories are used to showthat the area will remain in attainment. PADEP used 2017 and 2025 emissionprojections developed through the MARAMA regional planning process for the interim and maintenance plan end year, respectively. Emission projections, emission methodologies and growth factors for 2017 and 2025 can be found in the Technical SupportDocument for the Developmentof the 2013/201712020 Emission Inventoriesfor RegionalAir QualityModeling in the Northeast/Mid-Atlantic Region (MARAMA 2017 TSD) and the Technical SupportDocument for the Developmentof the 2025 Emission Inventoryfor PM2.5Nonattainment Counties in the MANE-VURegion, January 2012 (MARAMA 2025 TSD), respectively.
PADEP apportionedthe nonpoint and nonroad partial county emissions in the nonattainment areausing the same methodology as the 2005 and 2007 inventories. Since the 2007 base year, the NAAhas experienced growth in the oil and gas sector due to Marcellus Shale drilling activity. This will be discussed in the nonpoint emissions for 2017 and 2025.
For EGU emissions, PADEP used growth factors based on the Annual Energy Outlook (AE02011) and applied them to the 2007 inventory. Non-EGU emissions projections were based onVersion 3.3 ofthe 2007 MANE-VU+VA inventory. MARAMA growth factors were developed using AEO fuel consumption forecasts, state-level employmentprojections, and other state-specific emission projection data. Nonpoint source emissions for 2017 and 2025 were developed similarly to the non-EGU point sources. Emissionprojections were based onVersion 3.3 ofthe 2007 MANE-VU+VA inventory. MARAMA growth factors were developed using AEO fuel consumption forecasts, state-level employmentprojections, and other state-specific emissionprojection data. PADEP included emissions from the Marcellus Shale drilling activities into the nonpoint source inventory for 2017 and 2025. For compressor engines, PADEP used the 2013 Marcellus Shale Inventory submittedby natural gas producers as the basis for theirprojections. For other sources, where 2013 datawas not available, PADEP used the 2012 Marcellus Shale Inventory as the basis for projections. Unlike other nonpoint sources in the NAA, PADEP apportioned the Marcellus Shale emissions based on land usage as opposed to population. Thejurisdictions in the NAA partial counties ofArmstrong, Greene, Lawrence and Allegheny account for 10 percent, 3percent, 3 percent, and 2percent ofthe land area in the county.Nonroad source emissions for 2017 and 2025 were developed using NMIM model runs whichcontaindefault assumptions for projected years. Aircraft emissions were projected by applying activity growth datareported inthe Federal AviationAdministration's (FAA's) Terminal AreaForecast (TAF) system for 2009-2030 (FAA201 0). Railroad emissions were based onthe MARAMA MANE-VU+Vainventory.
The 2017 and 2025 onroad mobile source inventory was developed using EPA's highway mobile source emissions model MOVES2010. PADEP used local activity to replace default inputs in the model where appropriate
OAMA staffreviewed the methodologies providedby PADEP and found themto be acceptable.