Technical Support Document (TSD) For 

Pittsburgh-Beaver Valley PM 2.5 Nonattainment Area:

State Implementation Plan (SIP) Attainment Demonstration

and Base Year Inventory

Submitted November 2009 by the Pennsylvania 

Department of Environmental Protection 

TSD Prepared July 2010 by

Alice H. Chow

Air Quality Analysis Branch, 3AP40

U.S. Environmental Protection Agency, Region 3

1650 Arch Street

Philadelphia, Pennsylvania 19103

_____________________/s/_______________________

Reviewed by Walter Wilkie, Director

Office of Air Monitoring and Analysis (3AP40)

_______August 12, 2010__________

Date Signed

 
I. Introduction

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

Air Monitoring and Analysis (OAMA) review of the emissions inventories submitted 

with the Pittsburgh-Beaver Valley PM 2.5 Nonattainment Area State Implementation 

Plan (SIP) by the Pennsylvania Department of Environmental Protection (PADEP). This 

review determines the approvability of the SIP Base Year Inventory and an evaluation of 

the methods used. A SIP Base Year Inventory is the starting point from which other SIP 

inventories are derived as well as serving as the benchmark for other SIP planning 

activities, such as the establishment of an emissions reduction credit program. On January 

5, 2005 the Pittsburgh-Beaver area, comprised of Beaver, Butler, Washington, and 

Westmoreland counties and portions of Allegheny, Armstrong, Greene and Lawrence 

counties, was designated as nonattainment for the PM2.5 NAAQS. Any questions 

pertaining to this technical summary should be directed to Walter K. Wilkie, Associate 

Director, Office of Air Monitoring and Analysis, at 215-814-2150 or via email at 

wilkie.walter@epa.gov. 

II. 2002 SIP Base Year Inventory

The SIP base year inventory is the primary inventory from which other 

inventories (3-year cycle inventories, reasonable further progress inventories, modeling 

inventories) are derived. The Clean Air Act calls for State, local, and Tribal agencies to 

ensure that the base year inventory is comprehensive, accurate, and current for all actual 

emissions.1 The base year inventory includes emissions estimates from stationary point 

and nonpoint sources, onroad mobile sources, and nonroad mobile sources. For the 

PM2.5 NAAQS, the pollutants to be inventoried are PM 10, PM2.5, VOC, NOx, SO2 and 

NH3. For the NAAQS, emissions should be reported as actual annual emissions.

The Point Source data for 2002 is derived from the Air Information Management 

System /environment, Facility, Application, Compliance Tracking System 

(AIMS/eFACTS). The AIMS/eFACTS database is comprised of sources identified and 

inventoried by PADEP’s regional and central offices through permitting, field 

inspections, and surveys. Surveys are conducted annually as facilities must submit 

emission estimates for various operations, throughputs, work hours, as well as process 

data, such as combustion unit data and fuel characteristics. In 2002, PADEP noted that 

many facilities did not include condensable PM in their estimates of direct PM emissions. 

MANE-VU included both filterable and condensable PM estimates for their regional 

modeling efforts.

For the 2002 Nonpoint Source emissions, also known as “area sources,” PADEP 

provided an inventory that contained estimations of emissions by multiplying an emission 

factor by some known indicator or activity level for each category at the county level. 

 

1

“Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient 

Air Quality Standards (NAAQS) and Regional Haze Regulations” EPA-454/R-05-001, August 2005, 

updated November 2005.
These emissions are typically calculated on an annual basis because the activity data are 

generally only available on an annual basis. Nonpoint source estimates were provided by 

SCC.

The Nonroad Mobile Source 2002 inventory was prepared with EPA’s 

NONROAD2005 model. NONROAD estimates fuel consumption and emissions of total 

hydrocarbons, carbon monoxide, nitrogen oxides, sulfur dioxide, and particulate matter 

for all nonroad mobile source categories except for aircraft, locomotives, and commercial 

marine vessels. The National Mobile Inventory Model (NMIM) was used to estimate 

emissions of ammonia from sources contained in the NONROAD model. PADEP 

provided emission estimates for locomotive engines and aircraft emissions separately. 

For locomotive engine emissions, PADEP projected emissions from a 1999 survey using 

national fuel consumption information and EPA emission and conversion factors. 

Emissions from commercial aircraft and small airport operations for 2002 were estimated 

using the EPA-approved Emissions and Dispersion Modeling System (EDMS) 4.20, the 

latest version available at the time the inventory was developed. PADEP estimated 

emissions using operations data obtained from the United States Department of 

Transportation, Federal Aviation Administration’s (FAA) Terminal Area Forecast for 

commercial aircraft operations and the Airnav.com website for military operations. 

Using this operations data, emissions were modeled directly using the EDMS. 

Commercial marine vessels emissions from the Port of Pittsburgh were estimated using 

EPA’s “Commercial Marine Activity for Great Lakes and Inland River Ports in the 

United States, Final Report,” as well as discussions with tug boat operators. All Nonroad 

mobile source emissions were provided by SCC and classification.

The Onroad Mobile Source 2002 emissions inventory was developed using the 

most current version of EPA’s highway mobile source emissions model MOBILE 6.2. 

PADEP also used PPSUITE, an enhanced version of the Post Processor for Air Quality 

software systems used for previous inventory submissions in Pennsylvania. The 

Pennsylvania Department of Transportation (PennDOT) provided estimates of vehicle 

miles traveled (VMT) by vehicle type and roadway type. PADEP provided sample 

Mobile6.2 input files and estimate results for review. 

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

them to be approvable.