Technical Support Document (TSD) for the 

Redesignation Request and Maintenance Plan 

For the Pittsburgh-Beaver Valley, PA 2006 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) 
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 2006 PM2.s 

Nonattainment Area (NAA) by the Pennsylvania Department of Environmental Protection 

(PADEP). The NAA consists of portions 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. 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 nomoad 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 omoad 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 NEI 

onroad emissions were generated using the MOBILE 6 model which was subsequently replaced 

by the MOVES model. 
OAMA staffreviewed the files and the emission results provided by PADEP and found 

them to be acceptable. 

III. Emissions Inventories for Maintenance Plan 

2011 Attainment Year Inventory and Maintenance Plan Base Year Inventory 

Under section 172(c)(3) states are required to submit a comprehensive, accurate, current 

accounting of actual emissions from all sources (point, nonpoint, nonroad, and onroad) in the 

nonattainment area. This inventory contains primary PM2.s emissions (including condensibles), 

S02, NOx, VOC, and NHJ. 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 2011 emissions inventory that was 

used in the Pittsburgh-Beaver Valley Redesignation Request and Maintenance Plan in order to 

fulfill the 172(c)(3) and the attainment year emissions inventory requirements. 

For the 20II base year inventory for the point, nonpoint, and nonroad categories, PADEP 

used EPA's 2011 National Emissions Inventory (NEI) V2. Documentation to support the NEI 

can be found at http://www.epa.gov/ttn/chief/net/20IIinventory.html. 

The 2011 onroad mobile source inventory was developed by PADEP using EPA's 

highway mobile source emissions model MOVES20 10. PADEP used local activity to replace 

default inputs in the model where appropriate. Detailed road segment data was used to 

appropriately apportion emissions in the partial counties. 

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. P ADEP 

used 2017 and 2025 emission projections developed through the MARAMA regional planning 

process for the interim and maintenance plan end year, respectively. Typically projection 

inventories use the attainment year base year as the basis of their projections, however PADEP 

used projections previously developed with a 2007 base year inventory. A comparison of the 

2007 and 2011 year inventories shows that using the 2007 as a base year is a conservative 

approach, since emissions in 2007 were higher than 20 II emissions. Emission projections, 

emission methodologies and growth factors for 2017 and 2025 can be found in the Technical 

Support Document for the Development of the 20131201712020 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 A1mual Energy Outlook 

(AE02011) and applied them to the 2007 inventory. Non-EGU emissions projections were 

based on Version 3.3 ofthe 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 ofthe 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 (FAA2010). 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 PADEP and found them to be 

acceptable.