Technical Support Document (TSD) for the 

Redesignation Request and Maintenance Plan 

For the Pittsburgh-Beaver Valley, P A 1997 PM2.s Nonattainment Area 

Submitted December 2014 by the 

Pennsylvania Department of Environmental Protection 

TSD Prepared April 2015 by 

Jessica L. Fry 

Office of Air Monitoring and Analysis, 3AP40 

U.S. Environmental Protection Agency, Region 3 

1650 Arch Street 

Philadelphia, Pennsylvania 19103 

Reviewed by Alice H. Chow, Associate Director 

Office of Air Monitoring and Analysis (3AP40) 

Oil~>- ~ I) 

ate Stgned 
I. Introduction 

The purpose of this document is to provide a technical summary of the Office of Air 

Monitoring and Analysis (OAMA) review of the 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 of Environmental Protection 

(PADEP). The NAA consists ofportions of Allegheny, Armstrong, Greene, and Lawrence 

Counties as well as the whole counties of Beaver, Butler, Washington, and Westmoreland in 

Pennsylvania. This review does not determine the approvability of the 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 year the 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 then projected to show that 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 FR 47115). Any questions pertaining to this technical 

summary should be directed to Alice H. Chow, Associate Director, Office of Air Monitoring and 

Analysis, at 215-814-2144 or via email at chow.alice@epa.gov. 

II. Emissions Inventories for Redesignation Request 

2005 Nonattainment Year Inventory 

In a redesignation request, emissions inventories are used to support the State's claim that 

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. For the purpose of this plan, the 

year 2005 was used as the nonattainment year inventory. The 2005 nonattainment year inventory 

contains primary PM2.s emissions (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 of Allegheny, 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% ofthe population, respectively is included 

in the NAA. 

For the 2005 oruoad inventory P ADEP 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 NEI 
onroad emissions were generated using the MOBILE 6 model which was subsequently replaced 

by the MOVES model. 

OAMA staff reviewed the files and the emission results provided by PADEP and found 

them to be acceptable. 

III. Emissions Inventories for Maintenance Plan 

2007 Attainment Year Inventory and Maintenance Plan Base Year Inventory 

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 show the 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 order to fulfill 

the attainment year emissions inventory requirements. 

For the 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 

Air Management Association (MARAMA) regional planning process. Documentation of the 

development ofthe inventory can be found in Technical Support Document for the Development 

of the 2007 Emission Inventory for the Regional Air Quality Modeling in the Northeast I MidAtlantic 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 of which 98.47%, 3.96%, 4.06%, and 

1.15% ofthe population, 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. P ADEP used 2008 NEI data to 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 of the 

NONROAD model, they were calculated separately outside of the NONROAD model. Aircraft 

emissions were developed using EPA's database to the support the 2008 NEI. PADEP used 
railroad emissions developed by the Eastern Regional Technical Advisory Committee (ERTAC). 

To calculate values for the the partial counties included in the NAA, P ADEP used county data 

apportioned by population. 

The 2007 onroad mobile source inventory was developed using EPA's highway mobile 

source emissions model MOVES20 10. P ADEP used local activity to replace default inputs in 

the model where appropriate. 

OAMA staff reviewed the files and the emission results provided by P ADEP and found 

them to be acceptable. 

2017 and 2025 Projection Emission Inventories 

Projection inventories are used to show that the area will remain in attainment. PADEP 

used 2017 and 2025 emission projections 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 

Support Document for the Development of the 2013/201712020 Emission Inventories for 

Regional Air Quality Modeling in the Northeast/Mid-Atlantic Region (MARAMA 2017 TSD) 

and the Technical Support Document for the Development of the 2025 Emission Inventory for 

PM2.5 Nonattainment Counties in the MANE-VU Region, January 2012 (MARAMA 2025 TSD), 

respectively. 

P ADEP apportioned the nonpoint and nonroad partial county emissions in the 

nonattainment area using the same methodology as the 2005 and 2007 inventories. Since the 

2007 base year, the NAA has 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 on Version 3.3 of the 2007 MANE-VU+VA inventory. MARAMA growth factors were 

developed using AEO fuel consumption forecasts, state-level employment projections, and other 

state-specific emission projection data. 

Nonpoint source emissions for 2017 and 2025 were developed similarly to the non-EGU 

point sources. Emission projections were based on Version 3.3 of the 2007 MANE-VU+VA 

inventory. MARAMA growth factors were developed using AEO fuel consumption forecasts, 

state-level employment projections, and other state-specific emission projection 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 submitted by natural gas producers as the basis for their projections. For other 

sources, where 2013 data was 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. The jurisdictions in 

the NAA partial counties of Armstrong, Greene, Lawrence and Allegheny account for 10 

percent, 3 percent, 3 percent, and 2 percent of the land area in the county. 
Nonroad source emissions for 2017 and 2025 were developed using NMIM model runs 

which contain default assumptions for projected years. Aircraft emissions were projected by 

applying activity growth data reported in the Federal Aviation Administration's (FAA's) 

Terminal Area Forecast (TAF) system for 2009-2030 (F AA20 1 0). Railroad emissions were 

based on the MARAMA MANE-VU+Va inventory. 

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 staff reviewed the methodologies provided by P ADEP and found them to be 

acceptable.