Technical Support Document (TSD) For 

Liberty-Clairton PM 2.5 Nonattainment Area:

State Implementation Plan (SIP) Attainment Demonstration

and Base Year Inventory

Submitted April 2011 by the Pennsylvania 

Department of Environmental Protection 

TSD Prepared October 2011 by

Jessica Fry

Office of Air Monitoring and Analysis, 3AP40

U.S. Environmental Protection Agency, Region 3

1650 Arch Street

Philadelphia, Pennsylvania 19103

/s/

____________________________________________

Reviewed by Andrew Hass, Acting Associate Director

Office of Air Monitoring and Analysis (3AP40)

October 5, 2011

_______________

Date Signed

 
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 Liberty-Clairton PM 2.5 Nonattainment Area State Implementation Plan (SIP) 

by the Allegheny County Health Department (ACHD). 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 LibertyClairton area, located in Allegheny County and comprised of the boroughs of Glassport, 

Liberty, Lincoln, Port Vue, and the city of Clairton was designated as nonattainment for 

the PM2.5 NAAQS. Any questions pertaining to this technical summary should be 

directed to Andrew Hass, Acting Associate Director, Office of Air Monitoring and 

Analysis, at 215-814-2049 or via email at hass.andrew@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, nonroad mobile sources, and onroad 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. 

In the Liberty-Clairton area SIP the base year used was 2002. ACHD provided a 

point source inventory developed by the Mid-Atlantic/Northeast Visibility Union 

(MANE-VU) that contained emissions for five facilities in the nonattainment area. These 

stationary point sources included two major sources, two “synthetic minor” sources, and 

one minor source. ACHD made corrections to the point source inventory which involved 

the addition of condensable PM emissions for EGUs based on stack tests and revised 

emission factors.

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

provided an inventory developed by MANE-VU that contained estimations of emissions 

by multiplying an emission factor by some known indicator or activity level for each 

category at the county level. 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 and were apportioned to the Liberty-Clairton 

area based on population counts.

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

NONROAD2005 model. NONROAD estimates fuel consumption and emissions of total 

 

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.
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, aircraft emissions, and commercial 

marine vessels (CMV) emissions separately. The emissions submitted were developed 

by E.H. Pechan and Associates for MANE-VU. All Nonroad mobile source emissions 

were provided by SCC and classification and were apportioned to the Liberty-Clairton 

area based on population.

The Onroad Mobile Source 2002 emissions inventory was developed using EPA’s 

highway mobile source emissions model MOBILE 6.2. The data was compiled by PA 

DEP for Southwestern PA, with a separate estimate done for the Liberty-Clairton area. 

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. The mobile source VMT and 

emissions for the Liberty-Clairton area were estimated using GIS and the PennDOT 

Roadway Management System (RMS).

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

them to be approvable.