Revision to the

Allegheny County Portion of the 

Pennsylvania State Implementation Plan

Supplement to the 

Attainment Demonstration for the

Liberty-Clairton

PM2.5 Nonattainment Area

2006 Standards

Allegheny County Health Department

Air Quality Program

May 13, 2014
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds, Supp. May 2014 Page - 2 -

{This page left blank for printing purposes}
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds, Supp. May 2014 Page i

TABLE OF CONTENTS

1 Executive Summary.............................................................................................................. 1

2 Transportation Conformity Analysis.................................................................................. 3

2.1 Problem Statement ........................................................................................................... 3

2.2 Insignificance Statement .................................................................................................. 3

2.3 Onroad Mobile Source Inventory Development .............................................................. 4

2.3.1 Model ........................................................................................................................ 4

2.3.2 Emissions/Modeling Assistance ............................................................................... 6

2.3.3 Interagency Consultation .......................................................................................... 6

2.3.4 Methodology............................................................................................................. 7

2.4 Insignificance Finding Factor 1: Motor Vehicle Emissions Constitute a Low 

Percentage of Total SIP Inventory............................................................................................ 19

2.5 Insignificance Finding Factor 2: Current State of Air Quality as Determined by 

Monitoring Data for PM2.5 in the Liberty-Clairton Area .......................................................... 22

2.6 Insignificance Finding Factor 3: Absence of SIP Motor Vehicle Control Measures.... 26

2.6.1 Transportation Control Measures ........................................................................... 26

2.6.2 Current Control Requirements................................................................................ 26

2.6.3 Review of RACM ................................................................................................... 26

2.7 Insignificance Finding Factor 4: Historical Trends and Future Projections of the 

Growth of Motor Vehicle Emissions........................................................................................ 28

2.8 Motor Vehicle Emissions Insignificance Findings Conclusions ................................... 30

3 Projected Electric Generating Unit Emissions................................................................. 31

4 Legal Documents................................................................................................................. 39

4.1 Notice of Public Hearing and Comment Period............................................................. 39

4.2 Transmittals of Hearing Notice to PA DEP and EPA.................................................... 40

4.3 Proof of Publication and Certification of Public Hearing.............................................. 42

4.4 Summary of Public Comments and Responses.............................................................. 44

4.5 Certification of Adoption ............................................................................................... 49

References.................................................................................................................................... 50
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds, Supp. May 2014 Page ii

List of Tables................................................................................................................................. ii

List of Figures............................................................................................................................... iii

List of Appendices........................................................................................................................ iii

Acronyms and Abbreviations ..................................................................................................... iv

LIST OF TABLES

Table 2-1. Summary of Analysis Tools ...................................................................................... 8

Table 2-2. Summary of Mobile Source Data Parameters for Liberty-Clairton..................... 9

Table 2-3. Base and Forecasted Vehicle Miles of Travel (Millions)...................................... 15

Table 2-4. Vehicle Population Estimated Classified by MOVES Source Type.................... 16

Table 2-5. Liberty-Clairton PM2.5 NAA Onroad Emissions Summary by Road Type 

(Tons/Year)............................................................................................................... 17

Table 2-6. Liberty-Clairton PM2.5 NAA Onroad Emissions Summary by Fuel Type* 

(Tons/Year)............................................................................................................... 17

Table 2-7. Baseline 2007 Emissions (Tons/Year) .................................................................... 20

Table 2-8. Future Projected 2014 Emissions (Tons/Year) ..................................................... 20

Table 2-9. Onroad Highway Mobile Sources RACM Analysis Summary............................ 26

Table 3-1. PJM Unit Deactivations by Plant Capacity, 2012-2015........................................ 33

Table 3-2. CAMD Reported 2012 SO2 and NOx Emissions (with Expected Reductions in 

PJM Territory for 2013-2015) and Interstate Transport Rules Projected 

Emissions, CSAPR States........................................................................................ 34

Table 3-3. Federal Consent Decrees for Units in PJM states................................................. 36
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds, Supp. May 2014 Page iii

LIST OF FIGURES

Figure 1-1. Map of the Liberty-Clairton Area within the Pittsburgh-Beaver Valley Area .. 1

Figure 2-1. PM2.5 FRM Annual Design Values, Allegheny County, 2000-2012 ................... 23

Figure 2-2. PM2.5 FRM 24-Hour Design Values, Allegheny County, 2000-2012.................. 23

Figure 2-3. Liberty and Clairton FRM Annual Design Values with Projected to 2014...... 24

Figure 2-4. Liberty and Clairton FRM 24-Hour Design Values with Projected to 2014 .... 24

Figure 2-5. Population Trends for Allegheny County, 2000-2010......................................... 28

Figure 3-1. CSAPR States ......................................................................................................... 32

Figure 3-2. PJM Interconnection Territory ............................................................................ 32

Figure 3-3. Long-Term Reported and Expected/Projected SO2 (tons), CSAPR States ...... 35

Figure 3-4. Long-Term Reported and Expected/Projected NOx (tons), CSAPR States...... 35

LIST OF APPENDICES

Appendix A. Detailed EGU Data by State/Unit

Appendix B. Supporting EGU Documentation

B-1. Homer City Plan Approval

B-2. PJM Deactivations

B-3. Consent Decrees

Appendix C. Back-Trajectory Analysis
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds, Supp. May 2014 Page iv

ACRONYMS AND ABBREVIATIONS

ACHD Allegheny County Health Department

BHSTE Bureau of Highway Safety and Traffic Engineering

BPR Bureau of Public Roads

CAIR Clean Air Interstate Rule

CA LEV II California Low Emission Vehicle II Program

CAMD Clean Air Markets Division

CFR Code of Federal Regulations

CSAPR Cross-State Air Pollution Rule

DSI Dry Sorbent Injection

ECO Electro-Catalytic Oxidation

EGU Electric Generating Unit

EPA The United States Environmental Protection Agency

FHWA Federal Highway Administration

FR Federal Register

FEM Federal Equivalent Method monitor

FGD Flue Gas Desulfurization

FRM Federal Reference Method monitor

GHG Greenhouse Gas

GVWR Gross Vehicle Weight Rating

HPMS Highway Performance Monitoring System

I/M Inspection and Maintenance Program

MANE-VU Mid-Atlantic/Northeast Visibility Union

MOVES Motor Vehicle Emission Simulator model

MPO Metropolitan Planning Organization

MSA Metropolitan Statistical Area

MVEB Motor Vehicle Emissions Budget

μg/m3 Microgram per cubic meter

μm Micrometer, or micron

NAAQS National Ambient Air Quality Standard

NAA Nonattainment Area

NEI National Emission Inventory (EPA database)

NH3 Ammonia

NLEV National Low Emission Vehicle Program

NOx Oxides of Nitrogen

NTD National Transit Database

OBD II On-Board Diagnostics

PA DEP Pennsylvania Department of Environmental Protection

PCV Pennsylvania Clean Vehicles Program

PennDOT Pennsylvania Department of Transportation

PM Particulate Matter (airborne) of any size

PM2.5 Particulate Matter less than or equal to a nominal 2.5 microns in aerodynamic 

diameter, also referred to as fine particulates

PM10 Particulate Matter less than or equal to a nominal 10 microns in aerodynamic 

diameter
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds, Supp. May 2014 Page v

RACM Reasonably Available Control Measure

RACT Reasonably Available Control Technology

RMS Roadway Management System

RPO Regional Planning Organization 

RTO Regional Transmission Organization

RVP Reid Vapor Pressure

SIP State Implementation Plan

SO2 Sulfur Dioxide

SOx Sulfur Oxides

SPC Southwestern Pennsylvania Commission

SWPA Southwestern Pennsylvania

TCM Transportation Control Measure

TIGER Topologically Integrated Geographic Encoding and Referencing

TR Transport Rule

TS|Pechan TranSystems|E.H. Pechan & Associates

VMT Vehicle Miles Traveled

VOC Volatile Organic Compound
{This page left blank for printing purposes}
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 1

1 Executive Summary

On June 21, 2013, the Pennsylvania Department of Environmental Protection (PA DEP) 

submitted to the United States Environmental Protection Agency (EPA) Region III a revision to 

the State Implementation Plan (SIP) pertaining to the attainment demonstration for the 2006 

PM2.5 National Ambient Air Quality Standards (NAAQS) for the Liberty-Clairton nonattainment 

area. This SIP revision is a supplement to that submittal and the Allegheny County Health 

Department (ACHD) SIP document dated May 10, 2013.

PM2.5 describes particulate matter that is less than or equal to 2.5 micrometers (μm, or micron). 

In 1997, EPA promulgated the PM2.5 NAAQS of 15.0 μg/m3 on an annual basis and 65 μg/m3 on 

a 24-hour basis. In 2006, the 24-hour PM2.5 standard was lowered to 35 μg/m3.

1

Most of the Pittsburgh Metropolitan Statistical Area (MSA) was designated as an 8-county 

nonattainment area for the 1997 and 2006 PM2.5 NAAQS, called the Pittsburgh-Beaver Valley 

area. A portion of southeastern Allegheny County, the Liberty-Clairton area, was designated as 

a separate nonattainment area within the larger Pittsburgh-Beaver Valley area (areas shown in 

Figure 1-1 below).

Figure 1-1. Map of the Liberty-Clairton Area within the Pittsburgh-Beaver Valley Area

 

1 EPA NAAQS: http://www.epa.gov/air/criteria.html
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 2

The June 21, 2013 SIP submittal provided a control strategy and attainment demonstration for 

the 2006 PM2.5 NAAQS for the Liberty-Clairton nonattainment area. Using emissions 

inventories and modeling already included as part of the June 21, 2013 SIP submittal, this 

supplemental SIP revision demonstrates that motor vehicle emissions for direct PM2.5 and NOx

are insignificant contributors to the air quality problem in the Liberty Clairton nonattainment 

area for both the 1997 and 2006 PM2.5 NAAQS. As a result, in accordance with the rules 

established in 40 CFR 93.109(f) and under EPA approval of the insignificance findings, the area 

would not be required to submit motor vehicle emissions budgets (MVEBs) for direct PM2.5 and

NOx or satisfy the emissions analysis for 40 CFR 93.118 or 40 CFR 93.119 for either the 1997 or 

2006 PM2.5 NAAQS.

Additionally, pursuant to 40 CFR 93.102(b)(2)(v), the area is not required to satisfy the 

emissions analysis requirements of either 40 CFR 93.118 or 93.119 for SO2, VOC, or NH3

because the submitted SIP did not establish motor vehicle emissions budgets for any of these 

precursors as part of an attainment strategy.

The modeling demonstration for mobile sources was performed using the Motor Vehicle 

Emissions Simulator (MOVES) model. Years included in the inventory and modeling were 2007 

for the baseline case, and 2014 for the future projected case.

This supplemental SIP revision also updates and revises the projected electric generating unit 

(EGU) emissions analysis included in the June 21, 2013 SIP submittal. Although the Clean Air 

Interstate Rule (CAIR) remains in place for EGU emissions allocations, the future case 2014 

Cross-State Air Pollution Rule (CSAPR) inventory was used for the modeling demonstration

since it reflected a more representative inventory. This supplemental SIP revision provides an 

updated and more detailed analysis of current and expected EGU emissions to support the use of 

CSAPR in the modeling demonstration.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 3

2 Transportation Conformity Analysis

2.1 Problem Statement

Section 176 of the Clean Air Act (CAA) provides a mechanism by which federally funded or 

approved highway and transit plans, programs, and projects are determined not to produce new 

air quality violations, worsen existing violations, or delay timely attainment of the NAAQS or 

delay any interim milestones. EPA regulations in 40 CFR Part 93 pertaining to transportation 

conformity provide that motor vehicle emission “budgets” establish caps of these emissions that 

cannot be exceeded by the predicted transportation system emissions in the future.

Transportation agencies in Pennsylvania are responsible for making timely transportation 

conformity determinations. The responsible agency in the Pittsburgh area is the Southwestern 

Pennsylvania Commission (SPC), the designated Metropolitan Planning Organization (MPO) 

under federal transportation planning requirements.

40 CFR 93.102 requires conformity determinations to be applicable to direct emissions of PM2.5 

and NOx (unless a determination is made that transportation-related emissions are not significant 

contributors to PM2.5), and to emissions of SO2, VOC, and NH3 only if the applicable SIP or SIP 

submittal establishes an approved or adequate motor vehicle emissions budget as part of a 

reasonable further progress, attainment, or maintenance strategy.

The June 21, 2013 SIP submittal showed that controls for VOC and NH3 contributed minimally 

to modeled reductions and that SO2 emissions from mobile sources are very small in comparison 

to those from stationary sources. Therefore, MVEBs were not established for these precursors.

2.2 Insignificance Statement

Federal transportation conformity requirements in 40 CFR Part 93.109 allow for 

pollutants/precursors to be exempt from conformity analysis under certain circumstances.

40 CFR 93.109(f) Areas with insignificant motor vehicle emissions. 

Notwithstanding the other paragraphs in this section, an area is not required to satisfy a 

regional emissions analysis for §93.118 and/or §93.119 for a given pollutant/precursor 

and NAAQS, if EPA finds through the adequacy or approval process that a SIP 

demonstrates that regional motor vehicle emissions are an insignificant contributor to the 

air quality problem for that pollutant/precursor and NAAQS. The SIP would have to 

demonstrate that it would be unreasonable to expect that such an area would experience 

enough motor vehicle emissions growth in that pollutant/precursor for a NAAQS 

violation to occur. Such a finding would be based on a number of factors, including the 

percentage of motor vehicle emissions in the context of the total SIP inventory, the 

current state of air quality as determined by monitoring data for that NAAQS, the 

absence of SIP motor vehicle control measures, and historical trends and future 

projections of the growth of motor vehicle emissions. . . {emphasis added}
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 4

For the reasons outlined in Sections 2.4 through 2.7 of this document, ACHD has determined 

that highway emissions of direct PM2.5 and NOx are insignificant contributors to the 

nonattainment of the 1997 and 2006 PM2.5 NAAQS for the Liberty-Clairton area and that no 

motor vehicle emissions budgets are required for this nonattainment area and that the area should 

not be required by EPA to satisfy a regional emissions analysis for §93.118 or §93.119 for direct 

PM2.5 and NOx.

2.3 Onroad Mobile Source Inventory Development

This section describes the approach used to develop the onroad mobile source inventory for the 

Liberty-Clairton area, including a discussion of the data sources, parameters, and overall analysis 

approach. The highway inventory utilizes EPA’s new emission model, the Motor Vehicle 

Emissions Simulator (MOVES). The analysis approach and data assumptions were consistent 

with EPA technical guidance and other statewide inventories conducted by PA DEP. This 

included the use of roadway and traffic count data from the Pennsylvania Department of 

Transportation (PennDOT), accepted post processing software to estimate hourly speeds, and 

traffic and vehicle population growth rates utilizing available PennDOT and regional data 

sources. Other traffic, environmental, vehicle fleet, fuel, and control strategy inputs have been 

prepared using the latest local-specific planning assumptions. 

2.3.1 Model

MOVES2010a was used as the most recent version of the MOVES software. MOVES2010a

represents a significant departure from the previous MOBILE6.2 model, including new vehicle 

emission rates reflecting the latest regulations pertaining to fuel efficiency and vehicle emission 

standards.

MOVES2010a results can depend upon the unique circumstances of each nonattainment or 

maintenance area. The emission comparisons to MOBILE6.2 depend very heavily on the

pollutants of concern, the dates of concern, and on existing local control measures, traffic 

patterns, fleet age, and the mix of cars and trucks. In some cases, a change from MOBILE6.2 to 

MOVES2010/MOVES2010a may result in increased emissions estimates, while in other cases it 

may result in decreased emissions estimates for various time periods.2

Over the last ten years, EPA’s in-use data about technologies such as Tier 2, second-generation 

onboard diagnostics (OBD II), and enhanced evaporative emission control systems have 

dramatically improved. For MOVES2010, EPA has been able to carefully study these newer 

technologies, examining millions of results for light-duty vehicles. A detailed analysis of 70,000 

vehicles in Arizona’s Inspection and Maintenance (I/M) program provided information on how 

vehicles from the late-1990’s and early 2000’s age. Other I/M and remote sensing data and 

special purpose studies helped EPA to better understand trends in VOC, CO, and NOx emissions 

for light-duty cars and trucks. In reviewing these data, EPA found little change in CO from the 

 

2 EPA MOVES web site: http://moves.supportportal.com/link/portal/23002/23024/Article/32004/Howare-the-changes-in-emission-rates-in-MOVES2010-or-MOVES2010a-expected-to-affect-attainmentdemonstrations
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 5

original MOBILE6.2 projections, lower VOC emissions, and a noticeable increase in NOx

emissions. 

Also in support of MOVES2010 development, EPA conducted a landmark study of PM 

emissions, testing nearly 500 gasoline-fueled light-duty cars and trucks in Kansas City, MO. 

Due to the technical difficulties associated with measuring PM emissions, the Kansas City study 

– a collaborative effort including EPA, DOT, the Department of Energy (DOE), and the 

automotive and petroleum industries – was the largest such study ever conducted. The Kansas 

City study confirmed that PM emissions from light-duty gasoline-fueled vehicles are higher than 

earlier predicted, and clearly showed that cold ambient temperatures can dramatically increase 

PM start emissions. The MOVES2010 model includes these increases in PM start emissions at 

low temperatures. 

EPA’s understanding of emissions from heavy-duty vehicles has continued to improve since 

MOBILE6.2 was issued. Most earlier heavy-duty emission rates were based on certification 

tests of then-new, mid-1990’s engines. For MOVES2010, EPA has been able to analyze data on 

more than 400 in-use trucks, some in the laboratory and some with on-road measurement 

equipment. This allowed EPA to understand how real trucks pollute at a range of speeds and 

driving conditions. EPA also has been able to better incorporate emissions from heavy-duty 

diesel crankcase ventilation and from extended idling (also known as “hotelling”) – two emission 

processes that were relatively unstudied at the time MOBILE6.2 was developed. The 

incorporation of this additional data accounts for the increases in heavy-duty NOx and PM 

emissions reflected in MOVES2010. Emission differences in MOVES2010 are especially large 

for heavy-duty PM emissions because they reflect updated data on the effects of both speed and 

vehicle deterioration not previously available.3

In MOBILE6.2, PM emission rates had little or no variation due to vehicle speed, deterioration 

or aging effects, or ambient temperature. The development of MOVES included the 

incorporation of the results of significant amounts of vehicle testing that was not included in 

MOBILE6.2. Thus, within MOVES, the PM emission rates now vary depending on the 

temperature, speed, and age of vehicles. The relative effect of each of these factors will also 

differ from year to year, as different emission standards are phased into the fleet, since the 

percentage change from the base MOBILE6.2 PM emissions rates to the MOVES base emission 

rates varies by model year.

 

3 Taken from “EPA Releases MOVES2010 Mobile Source Emissions Model: Questions and Answers,” 

EPA-420-F-09-073, U.S. EPA, Office of Transportation and Air Quality, December 2009: 

http://www.epa.gov/otaq/models/moves/420f09073.pdf
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 6

2.3.2 Emissions/Modeling Assistance

As described in the SIP submittal of June 21, 2013, ACHD contracted TranSystems|E.H. Pechan 

& Associates (TS|Pechan) to conduct an in-depth investigation of transportation sources of PM2.5

in southern Allegheny County.

4

Specifically, TS|Pechan reviewed existing PM2.5 inventories and related documents for local 

mobile sources. The review included field work, records and data searches, and calculations 

necessary to develop 2007 and projected 2014 mobile source inventories. Furthermore, 

TS|Pechan performed a reasonably available control measures (RACM) analysis, which included 

examining reasonably available control technology (RACT), on all mobile sources listed in the 

revised 2007 SIP emissions inventory. 

2.3.3 Interagency Consultation

The analysis methodologies and data sources have undergone review from multiple agencies. 

The Pennsylvania Transportation Air Quality Working Group, a state-wide interagency 

consultation group including federal (EPA, Federal Highway Administration (FHWA)), state 

(PennDOT, PA DEP), and regional (MPOs) agencies, has played a key role in reviewing the 

MOVES emission calculation process, local data sources, and methods in determining future 

growth for vehicle miles of travel (VMT) and vehicle population.

 

4 ACHD contract title Consultant Technical Support for Air Pollutant Area and Mobile Sources Analyses.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 7

2.3.4 Methodology

Guidance documents from EPA were used to develop the base and future year emissions 

inventories for the Liberty-Clairton 2006 PM2.5 NAAQS nonattainment area (NAA) and include:

 Policy Guidance on the Use of MOVES2010 for SIP Development, Transportation 

Conformity, and Other Purposes, EPA Office of Air and Radiation, EPA-420-B-09-046, 

December 2009 (EPA, 2009)

 Technical Guidance on the Use of MOVES2010 for Emission Inventory Preparation in 

State Implementation Plans and Transportation Conformity, EPA Office of Air and 

Radiation, and Office of Transportation and Air Quality, EPA-420-B-10-023, April 2010

(EPA, 2010a)

 Motor Vehicle Emission Simulator, User Guide for MOVES2010a, EPA-420-B-10-036, 

August 2010 (EPA, 2010b)

The highway mobile source emission inventory was developed using available travel data and 

EPA’s MOVES2010a emission model. The methodologies used in the development of this 

inventory conform to the recommendations provided in EPA’s Technical Guidance, cited above. 

A mix of local data and national data (internal to MOVES2010a) has been used for this 

submission. Local data was used for the more significant inputs into the process and include:

 Vehicle miles traveled by vehicle type (VMT)

 Average speed distribution

 Vehicle type mixes

 Source type population (for light-duty vehicles)

 Vehicle age distribution

 Hourly distributions

 Meteorology data

 Inspection/Maintenance (I/M) program

 Fuel supply

The data used reflects the latest planning assumptions and is primarily based on data assembled 

from PennDOT’s Bureau of Motor Vehicles, the local MPO (SPC) and other local/national 

sources. Where available, 2007 data was used, however, 2008 data (projected back to 2007) that 

had already been vetted by stakeholders was also used as appropriate.

The analysis methodology is consistent with past statewide inventory efforts, including the 2008 

National Emissions Inventory (NEI) submission. This includes the use of custom post 

processing software to calculate hourly speeds and prepare key traffic input files to the 

MOVES2010a emission model.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 8

Analysis Tools

The mobile vehicle emissions inventory analysis utilizes several key software/programs for 

producing the county emissions totals. These tools are outlined in Table 2-1.

Table 2-1. Summary of Analysis Tools

Tool Purpose

MOVES2010a Produces emission rates for each PM2.5 precursor

PPSUITE

Processes the highway data; calculates hourly congested speeds for each state 

roadway segment; prepares MOVES2010a input files; processes MOVES2010a 

output files into a summary report.

CENTRAL Provides a batch menu driven process to execute PPSUITE, MOVES2010a, and 

other MYSQL steps.

The Liberty-Clairton PM2.5 onroad inventory was developed using EPA’s MOVES2010a 

emission model. EPA’s MOVES model was officially released on March 2, 2010 and was 

followed with a revised version (MOVES2010a) in August 2010. The MOVES2010a model 

provides a more robust estimate of emissions as compared to its predecessor MOBILE6.2. 

MOVES2010a has been integrated with local traffic, vehicle fleet, environmental, fuel, and 

control strategy data to estimate emissions.

PPSUITE is an enhanced version of the Post Processor for Air Quality software system that has 

been used for previous inventory and conformity submissions in Pennsylvania. The software has 

undergone significant revisions to ensure consistency with the MOVES2010a. PPSUITE was 

used to calculate hourly congested speeds for each roadway link, apply vehicle type fractions, 

aggregate VMT, prepare MOVES2010a traffic-related input files, and process MOVES2010a 

outputs. The PPSUITE software and process methodologies are consistent with that used for 

state inventories and transportation conformity analyses throughout Pennsylvania. 

CENTRAL is a menu-driven software platform that executes the PPSUITE and MOVES2010a 

processes in batch mode. The software allows users to execute runs with a variety of input 

options and integrates custom MYSQL steps into the process. CENTRAL provides important 

quality control and assurance steps including file naming and storage automation.

Data Sources

The latest planning assumptions were used in preparing inputs to the MOVES emission model. 

The data includes Allegheny County specific parameters regarding temperatures, fuel, and fleet 

age. Specific traffic conditions and vehicle population have been prepared for the LibertyClairton nonattainment area. Much of the data has been prepared as part of inventory efforts in 

support of statewide analyses for the PA DEP, and has undergone review and acceptance by the 

Pennsylvania Transportation Air Quality Working Group, the interagency consultation group 

that consists of EPA, FHWA, PennDOT, PA DEP, and MPOs (SPC in this case).
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 9

Table 2-2 outlines all of the major data sources and processes proposed for this effort. The 

subsequent sections expand on these in greater detail.

Table 2-2. Summary of Mobile Source Data Parameters for Liberty-Clairton

Parameter Source

Analysis Years 2007, 2014

Season Annual – 12 Month Approach – 1 representative day per month

MOVES Domain / Calculation 

type

County / Inventory Mode

Pollutants PM2.5, NOx, SO2, NH3, VOC

Emission Calculation Method Inventory Mode

Area Liberty Clairton

Traffic Inputs

VMT Data Source 2008 PennDOT Roadway Management System (RMS) “Snapshot”

Integrated with PennDOT BHSTE GIS Signal Locations 

VMT Adjustments For 2008-2007: Highway Performance Monitoring System (HPMS) County by 

Functional Class VMT

For 2008-2014: Functional Class VMT & Growth Rates based on SPC 

Regional Travel Demand Model

Local VMT Adjustments Using GIS, the portion of TIGER local roadway mileage in the nonattainmentmaintenance area vs. county total – Apply ratio to the total HPMS local VMT 

reported for the county

Seasonal Adjustments Traffic Data Report PennDOT Bureau of Public Roads (BPR) (2008 Data)

Hourly Patterns Traffic Data Report PennDOT BPR (2008 Data)

Annual VMT Calculated by PPSUITE

Hourly Speeds Calculated by PPSUITE (Minimum Speed = 2.5 miles per hour) 

Road Type Distribution Calculated by PPSUITE; User assigned Road Type to RMS links 

MOVES Inputs

Vehicle Age Distribution 2010 registration data for light-duty vehicles from PennDOT’s Bureau of 

Motor Vehicles Registration Database; MOVES Defaults for Heavy-Duty 

Vehicles

Fuel Parameters

(Gasoline/Diesel)

MOVES2010a default data (except for gasohol market penetration and Reid 

vapor pressure (RVP) values, which were updated)

I/M Parameters PA OBD II & Idle

(Changes made to default I/M Program Parameters)

Temperatures 10-year monthly average hourly airport temperatures - humidity from 

WeatherBank, Inc. (www.weatherbank.com)

Month VMT Fractions Calculated based on seasonal adjustment factors

Day VMT Fractions Calculated based on seasonal adjustment factors 

Hour VMT Fractions Calculated by PPSUITE

Ramp Fraction MOVES Defaults (8% of vehicle hours traveled) 

Source Type Population 2007 - Based on 2008 registration data and MOVES default VMT and 

population. 2014 - Based on projected household growth from Woods and 

Poole Inc. (Methodology approved by PA Transportation Air Quality Working

Group, consisting of EPA, FHWA, DEP, Penn DOT.)

Early NLEV/PCV/CA LEV II EPA provided MOVES override database files 

Stage II MOVES Default Process 

Alternative Vehicle Technology MOVES Default (no input file provided)
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 10

Base Traffic Data/Fleet Data Inputs

a. Baseline Traffic Volumes

The 2008 PennDOT RMS database serves as the primary source for the county and 

functional class VMT estimates and roadway volumes for the baseline traffic data. The 

RMS has been updated to provide a “snapshot” of the regional roadway system and 

traffic volumes in 2008 and also includes traffic signal locations. As 2007 RMS data was 

not readily available, HPMS data was used to factor the 2008 volumes back to 2007 

levels, with individual adjustment factors calculated for each of the functional classes as 

they exist in the RMS database and are represented in the NAA. This procedure applies 

to all VMT, gasoline and diesel. Note that there are no limited access freeways or 

expressways within the Liberty-Clairton NAA and, as a result, growth factors were not 

developed for these roadway classifications.

The RMS database only includes roadways maintained by PennDOT. As a result, a 

significant number of local roadways are not fully represented in the database. PennDOT 

has procedures to estimate county local VMT as part of the HPMS reporting system. For 

the Liberty-Clairton inventory, local VMT was estimated as a percentage of the 

Allegheny County total. Using GIS, the portion of Topologically Integrated Geographic 

Encoding and Referencing (TIGER) local roadway mileage in the nonattainment area 

was calculated and compared to the total county mileage to estimate the relative portion.

The local VMT estimation for the nonattainment area was first derived using 3 different 

methods: 1) The PennDOT maintained Road Management System (RMS) was queried. 

GIS software was used to determine all local roadways within the nonattainment area, 

with VMT calculated directly from the data in that dataset. 2) The Census TIGER GIS 

file was used to determine the total roadway centerline mileage both within the 

nonattainment area and within the county as a whole. The ratio of the mileage within the 

nonattainment area to the total county mileage was use to allocate the total local roadway 

VMT as reported in the Federal HPMS for Allegheny County. 3) The percent of 

population (residents) within both the nonattainment area and the county as a whole was 

determined using census data. The ratio of these values was then applied to the local 

roadway VMT reported in the Federal HPMS database to obtain an estimate.

The method reporting the greatest local roadway VMT, used to be conservative, was the 

second method using roadway centerline mileage. The ratio was 1.76% of the total 

Allegheny County local VMT falling within the nonattainment area boundaries.

b. Seasonal Adjustments

The PPSUITE framework developed for this analysis calculates annual emissions by 

running MOVES for a single representative day for each month of the year (12 runs). Per 

the MOVES Technical Guidance option, monthly analyses were conducted only for the 

weekday option and factored to represent monthly/annual totals. The daily and monthly 

seasonal adjustment factors were developed from data contained in the document: 2008 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 11

Pennsylvania Traffic Data Report, prepared by PennDOT’s Bureau of Public Records 

(BPR, PennDOT, 2008). The seasonal and daily factors are based on statistical analyses 

of 2008 traffic counts taken at permanent and in-pavement automatic traffic recorders.

c. Congested Speeds

PPSUITE calculates congested speeds by hour of the day for each roadway segment and 

provides the information as input to the MOVES2010a software. The speed calculations 

found in PPSUITE are a variation of the BPR speed-flow formula and are fully consistent 

with the guidance provided by EPA and FHWA. To disaggregate the daily RMS 

volumes to hourly values, auto and truck hourly pattern data from PennDOT’s 2008 

Pennsylvania Traffic Data Report were used to develop distributions of traffic by hour, 

which in turn were used to create an input file used by PPSUITE in its internal 

calculations.

d. Vehicle Population

Vehicle population is a key component in the calculation of start and evaporative 

emissions. MOVES2010a requires vehicle population by 13 source types in order to 

determine evaporative emissions. Data from PennDOT registrations were first used to 

estimate county-specific values. Allegheny County 2008 vehicle registration data was

used to estimate vehicle population for light-duty vehicles and school buses. For transit 

buses, data from PennDOT and the National Transit Database (NTD) were used to 

estimate transit bus populations for the county. Next, the county information was 

factored to represent the Liberty-Clairton portion of the region. These adjustment factors 

were based on the proportion of population in the nonattainment area as compared to the 

county total. For all other heavy-duty vehicles, MOVES2010a national default vehicle 

mileage accumulation rates were applied to regional heavy-duty VMT to estimate heavyduty vehicle population. This methodology is consistent with the approach used in other 

areas in PA with nonattainment areas that do not constitute an entire county. The 

approach is also consistent with EPA recommended practice. No other sufficiently vetted 

data source was identified that would allow for additional refinement and meet the 

minimum requirements for data robustness.

Vehicle mileage accumulation by age is accounted for internally in the MOVES model. 

The MOVES table SourceTypeAge lists for each source type by age the relative annual 

mileage accumulation rate, the annual per vehicle mileage accumulation for a given 

MOVES SourceUseType and age, relative to the highest annual mileage accumulation 

rate within the HPMS Vtype. This is a national default MOVES table, not typically 

modified by MOVES users. The relative mileage accumulation rates are used to weight 

the age distribution data, essentially yielding a VMT-based age distribution. As an 

example, a 5-year old single unit short-haul truck has a relative mileage accumulation 

rate of 0.306 while a 10-year old single unit short-haul truck has a relative mileage 

accumulation rate of 0.187. Thus, the MOVES model assumes that each 5-year old 

single-unit short haul truck is being driven about 64% more than a comparable 10-year 

old truck per year. These mileage accumulation rates are used in combination with the 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 12

age distribution data to determine the by-model-year weight of the by-model-year 

emission rates.

Only a single relative mileage accumulation rate is used for each model year and source 

use type combination. Therefore, data on the mileage accumulation rates of all 5-yearold trucks (of a given source use type) would be considered to determine the weighted 

average accumulation rate of 5-year-old trucks.

e. VMT by Source Type

For input to the MOVES model, total VMT must be disaggregated into the six HPMS 

vehicle groups (passenger cars, other 2-axle light trucks, buses, single-unit trucks, 

combination trucks, motorcycles). This input is done internally by PPSUITE based on 

the vehicle mix patterns provided as input to the software. For this inventory, the vehicle 

mix patterns were calculated utilizing a combination of the following sources:

 2008 RMS truck percentages

 PennDOT and 2008 NTD transit data

 2008 school bus registration data

 EPA’s MOVES2010a default distribution for all other source types

The functional class groupings used in PPSUITE are necessary for HPMS reporting, 

however, they are not compatible with MOVES2010a. As a final step, PPSUITE reaggregates the VMT into MOVES2010a’s roadway classifications. This step is 

somewhat redundant as all roadways in the Liberty-Clairton PM2.5 NAA are classified in 

MOVES2010a as urban, non-restricted.

f. Vehicle Age Distribution

Vehicle age distributions for each of the 13 source types are a required input into 

MOVES2010a and PPSUITE. The distributions reflect the percentage of vehicles in the 

fleet up to 31 years old and must total 100 percent. Recent 2010 registration data from 

PennDOT’s motor vehicles registration database has indicated a substantially older fleet 

than recorded in the 2002-2008 period. As such, the 2010 vehicle age distributions have 

been used for this inventory. Due to insufficient data, only data for light-duty vehicles 

are used; heavy-duty vehicle age distributions are based on the MOVES2010a defaults 

for Allegheny County. As the registration data downloaded was based on MOBILE6.2 

vehicle categories, the data was converted to source types using the EPA convertor 

spreadsheets provided with the MOVES2010a emission model.

The MOVES 2010a registration data defaults for Allegheny County are national defaults 

for heavy-duty vehicles, relative to the calendar year being modeled. This is appropriate 

for heavy-duty vehicles, per the EPA guidance, as heavy-duty vehicles frequently operate 

in areas outside of the area in which they are registered.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 13

I/M and Fuel Parameters

a. I/M Program

The I/M program inputs to the MOVES2010a model are based on past and current 

programs at the county level (all Pennsylvania I/M programs are based on county 

boundaries). The MOVES2010a model has simplified the I/M program input parameters 

compared to MOBILE6.2. The default I/M program parameters included in 

MOVES2010a were examined and changes made to the defaults to match the actual local 

program.

The Pennsylvania I/M program was upgraded and expanded throughout the state with a 

phase-in period starting in September 2003 and was fully implemented by June 2004. 

The program requirements vary by region and include on-board diagnostics (OBD) 

technology. The program, named PA OBD II, has been implemented in the Pittsburgh 

Region, including Allegheny County. The program consists of the OBD II program, 

along with tailpipe tests (idle in this region) and gas cap tests.

b. Fuel Assumptions

The MOVES2010a default fuel formulation and fuel supply data was reviewed and 

updated based on available local volumetric fuel property information provided by PA 

DEP. The gasohol market penetration and RVP values was also updated, with 

MOVES2010a default data used for the remaining parameters. Updated assumptions 

included:

 0.00 percent ethanol (for summer RVP months)

 6.78 percent ethanol (for winter months)

 7.8 RVP during summer months

Meteorology Data

Updated weather information was obtained from WeatherBank, Inc. (www.weatherbank.com) 

using the 10-year average minimum and maximum monthly temperature and relative humidity 

values obtained at the Pittsburgh International Airport (PIT). The MOVES2010a model requires 

temperature and relative humidity data for each hour of the day. EPA’s data converters were 

used to convert minimum and maximum daily temperatures to an hourly temperature profile that 

could be input to MOVES2010a. These assumptions are consistent with recent inventory efforts. 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 14

Vehicle Technology/Programs

a. Federal Programs

Current federal vehicle emissions control and fuel programs are incorporated into the 

MOVES2010a software. These include the National Program standards covering model 

year vehicles through 2016. Modifications of default emission rates were required to 

reflect the early implementation of the National Low Emission Vehicle Program (NLEV) 

program in Pennsylvania. To reflect these impacts, EPA has released instructions and 

input files that can be used to model these impacts (EPA, 2010c). This inventory utilized 

the August 2010 version of the files (http://www.epa.gov/oms/models/moves/tools.htm).

b. State Programs

The Pennsylvania Clean Vehicles (PCV) Program, adopted in 1998, incorporated the 

California Low Emission Vehicle (CA LEV II) Program by reference, although it 

allowed automakers to comply with the NLEV program as an alternative to this 

Pennsylvania program until model year 2008. Beginning with model year 2008, “new” 

passenger cars and light-duty trucks with a gross vehicle weight rating (GVWR) of 8,500 

pounds or less, that are sold or leased and titled in Pennsylvania, must be certified by the 

California Air Resources Board or be certified for sale in all 50 states. For this program, 

a “new” vehicle is a qualified vehicle with an odometer reading less than 7,500 miles. 

PA DEP and PennDOT worked with the automobile manufacturers, dealers and other 

interested business partners and finalized procedures for complying with these new 

requirements.

The impacts of this program were modeled for all analysis years beyond 2008 using the 

same EPA guidance and tools as downloaded for the early NLEV analysis. EPA has also 

provided input files that reflect the CAL LEV II program. Modifications were made to 

these files to reflect the 2008 start date in Pennsylvania.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 15

Traffic Growth Assumptions

Traffic growth forecasting plays a pivotal role in estimating future year emissions for the region. 

There are many uncertainties affecting projections of traffic growth, including the current 

economic conditions, future growth in population and employment, etc. Growth rates for this 

emissions inventory were based on an assessment of available data sources.

All SIP mobile source highway inventories include the review and assessment of county-specific 

growth rates from a PennDOT study originally completed in 2005 and documented in the report, 

Statistical Evaluation of Projected Traffic Growth, Traffic Growth Forecasting System: Final 

Report, March 14, 2005 (Baker, 2005). As part of that study, a statewide traffic growth 

forecasting system was developed that incorporates traffic data from PennDOT’s Traffic 

Information System and socioeconomic forecasts. That forecasting system is maintained by the 

PennDOT BPR and is updated on a periodic basis. This system was last updated in December of 

2009 to develop new statistical relationships between historic VMT growth and population 

(through 2008). The forecast population was estimated from the Woods and Poole data “2010 

State Profile.” The results of the study have been shared between PennDOT, PA DEP, and other 

Pennsylvania Transportation Air Quality Working Group members.

The growth rates from the PennDOT BPR forecasting system were evaluated against other 

available data including the SPC travel model. For the development of motor vehicle emissions 

budgets (MVEBs), upper estimates of the VMT growth range are used for the forecast analyses. 

From an air quality perspective, the use of the upper boundary is conservative, and provides for 

factors outside the agency’s control (e.g., potential socio-economic growth above current 

forecasts, fleet age distributions, vehicle type distribution) that influence motor vehicle 

emissions.

For the Liberty-Clairton PM2.5 NAA, the PennDOT BPR Growth Rate forecasting system was 

used to convert 2008 volumes to 2007, while growth rates from 2007-2014 are based on the SPC 

regional travel demand model. Of the multiple sources reviewed, these yielded the highest 

estimates of traffic volumes and, in turn, the highest estimate of the onroad emissions. Base and 

forecasted VMT estimates are shown in Table 2-3.

Table 2-3. Base and Forecasted Vehicle Miles of Travel (Millions)

VMT (Millions)* % 

2007 2014 Change

94.701 107.171 13.2%

* All VMT is classified as 

Urban, Unrestricted in MOVES 

for Liberty-Clairton.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 16

Vehicle Population Growth Assumption

Vehicle population growth forecasting plays a key role in determining emissions for future years 

for the region. For this inventory, the vehicle population was forecasted by considering countyspecific household and population growth. Liberty-Clairton area vehicle population estimates by 

MOVES source types are shown in Table 2-4.

The household and population data was obtained from the PennDOT study documented in the 

reports discussed above, as well as the Statistical Evaluation of Projected Traffic Growth, Traffic 

Growth Forecasting System: Final Report, March 14, 2005. The forecast household and 

population were estimated from the Woods and Poole data “2010 State Profile.” The highest 

growth for household and population data was obtained for the county. The household growth 

rate yielded the higher value and did not exceed VMT growth. This value was ultimately used to 

project the 2007 vehicle population to 2014.

Table 2-4. Vehicle Population Estimated Classified by MOVES Source Type

MOVES 

Source Type 

ID

Vehicle 

Population

2007 2014

11 443 488

21 6,572 6,626

31 4,625 4,749

32 1,545 1,586

41 2 3

42 14 14

43 20 21

51 1 2

52 94 105

53 11 13

54 21 24

61 23 25

62 26 29

Total 13,397 13,685
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 17

Final Results

Table 2-5 summarizes the 2007 and 2014 onroad vehicle estimates for the Liberty-Clairton NAA 

by MOVES road type.

Table 2-5. Liberty-Clairton PM2.5 NAA Onroad Emissions Summary by Road Type 

(Tons/Year)

Table 2-6 provides an onroad emissions summary by fuel type for the Liberty-Clairton NAA, as 

well as the expected change in VMT and emissions between 2007 and 2014.

Table 2-6. Liberty-Clairton PM2.5 NAA Onroad Emissions Summary by Fuel Type*

(Tons/Year)

2007

Fuel Type

Annual VMT

(millions)

Speed

(miles/hour) PM2.5 VOC NOx SO2 NH3

Gasoline 88.717 29.1 4.17 164.42 175.63 1.80 4.51

Diesel Fuel 5.985 29.1 5.74 8.10 98.66 0.35 0.15

Area Total 94.701 29.1 9.91 172.52 274.29 2.15 4.66

2014

Fuel Type

Annual VMT

(millions)

Speed

(miles/hour) PM2.5 VOC NOx SO2 NH3

Gasoline 100.203 29.1 3.34 89.91 93.23 0.81 3.18

Diesel Fuel 6.968 29.1 2.84 5.15 57.80 0.09 0.18

Area Total 107.171 29.1 6.18 95.06 151.03 0.90 3.36

Change in VMT and Total Emissions: 2007-2014

Fuel Type

Annual VMT

(millions)

Speed

(miles/hour) PM2.5 VOC NOx SO2 NH3

Gasoline 11.486 - -0.83 -74.51 -82.39 -0.99 -1.33

Diesel Fuel 0.983 - -2.89 -2.95 -40.86 -0.26 0.02

Area Total 12.469 - -3.73 -77.46 -123.26 -1.24 -1.31

2007

Road Type

Annual VMT 

(millions)

Speed

(miles/hour) PM2.5 VOC NOx SO2 NH3

Off-Road - - 1.82 121.60 75.43 0.16 0.00

Urban Unrestricted 94.701 29.1 8.09 50.92 198.86 1.99 4.66

Area Total 94.701 - 9.91 172.52 274.29 2.15 4.66

2014

Road Type

Annual VMT 

(millions)

Speed

(miles/hour) PM2.5 VOC NOx SO2 NH3

Off-Road - - 1.16 72.74 51.72 0.07 0.00

Urban Unrestricted 107.171 29.1 5.02 22.32 99.31 0.84 3.36

Area Total 107.171 - 6.18 95.06 151.03 0.90 3.36
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 18

The speed given in Tables 2-5 and 2-6 is calculated by the internal processes within the 

PPSUITE software. PPSUITE uses a combination of “Best Practices Methods (BPM) speed 

curves” similar to those typically found in regional travel demand models, along with 

adjustments as found in the TRB Highway Capacity Manual to account for roadway geometry. 

This approach is based on common industry practice and is consistent with the approach used in 

other regional air quality planning analyses.

All input data was at a minimum coded to the first decimal place. PPSUITE internally uses 

floating point calculations which retain accuracy to 16 decimal places. While the table reports 

average vehicle speed to the first decimal place, that model-estimated value is more precise than 

the model’s ability to estimate such speeds.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 19

2.4 Insignificance Finding Factor 1: Motor Vehicle Emissions Constitute a Low 

Percentage of Total SIP Inventory

As specified by EPA guidance, pollutants inventoried as part of the June 21, 2013 SIP submittal 

for the Liberty-Clairton PM2.5 nonattainment area included PM10 and PM2.5 along with 

precursors SO2, NOx, VOC, and NH3. The emissions inventory included in the plan was

compiled for sources within the nonattainment area (City of Clairton, Glassport Borough, Liberty 

Borough, Lincoln Borough, Port Vue Borough). Sources in the emissions inventory include 

stationary point sources, area sources, nonroad sources, and onroad sources. 

In the June 21, 2013 SIP submittal, year 2007 was used for baseline emissions inventory and 

year 2014 was used for the projected inventory. The 2007 inventory provided actual emissions 

of a year when the Liberty-Clairton area was not attaining either the 1997 or the 2006 PM2.5

standards, and the SIP submittal showed projected attainment of the 2006 PM2.5 NAAQS by 

2014. The Liberty-Clairton area attained the 1997 PM2.5 NAAQS in 2011 and is currently 

attaining these standards. The SIP submittal included additional controls that will be 

implemented by 2014 to attain the 24-hour 2006 PM2.5 NAAQS and will also result in further 

reductions of annual PM2.5 concentrations. Therefore, these inventories are consistent with 

attainment of both the 1997 and 2006 PM2.5 NAAQS.

Emissions inventories for all source classifications were developed for the Mid-Atlantic / 

Northeast Visibility Union (MANE-VU) for use in regional analyses and SIPs by states in the 

Northeastern region of the United States. As described in the June 21, 2013 SIP submittal, the 

Liberty-Clairton emissions inventory was developed from the regional MANE-VU inventories 

with revisions by TranSystems|E.H. Pechan (TS|Pechan) for area, nonroad, and mobile sources 

and by ACHD for stationary point sources. Emissions given are “actual” values based on 

pollutant emission factors and throughputs or capacities of each emission source. Emissions do 

not represent permitted or “allowable” limits.

Source categories used for the emissions inventory are described below. The inventory listings 

are included in Appendix D of the June 21, 2013 SIP submittal, and information on the 

development of the baseline and projected emissions and modeling inventories are given in 

Appendices E and F of that same submittal.

 Stationary point sources are sources for which ACHD collects individual emissionsrelated information.

 Area sources are industrial, commercial, and residential sources too small or too 

numerous to be handled individually. These include but are not limited to commercial 

and residential open burning, architectural and industrial maintenance coatings 

application and clean-up, consumer product use, and vehicle refueling at service stations.

 Nonroad sources encompass a diverse collection of engines, including but not limited to 

outdoor power equipment, recreational vehicles, farm and construction machinery, lawn 

and garden equipment, industrial equipment, recreational marine vessels, commercial 

marine vessels, locomotives, ships, and aircraft.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 20

 Onroad sources include passenger cars and light-duty trucks, medium and heavy duty

trucks, buses and motorcycles. The Motor Vehicle Emissions Simulator (MOVES) 

model was utilized to generate emissions based on traffic counts, vehicle speeds, vehicle 

population growth, and other factors. Mobile source emissions for the Liberty-Clairton 

area were developed by TS|Pechan.

Emissions inventory summaries of PM2.5 and NOx for baseline and future projected cases are 

shown in Tables 2-7 and 2-8 below.

5

 These emissions represent those from sources only within 

the 5-municipality Liberty-Clairton area and not the surrounding area.

Table 2-7. Baseline 2007 Emissions (Tons/Year)

Liberty-Clairton Area (2007) PM2.5 NOx

Stationary Point Sources 946.6 4841.9

Area Sources 26.3 38.8

Nonroad Sources 15.0 437.9

Onroad Sources 9.9 274.3

Totals 997.8 5592.9

Onroad Percentages 0.99% 4.90%

Table 2-8. Future Projected 2014 Emissions (Tons/Year)

Liberty-Clairton Area (2014) PM2.5 NOx

Stationary Point Sources 662.7 4349.3

Area Sources 25.6 38.5

Nonroad Sources 12.4 387.1

Onroad Sources 6.2 151.0

Totals 706.8 4925.9

Onroad Percentages 0.88% 3.07%

 

5 Emissions of SO2, VOC, and NH3.are not shown since onroad budgets for these precursors are only 

required if it is determined that budgets are necessary in order for the SIP to achieve its purpose of 

achieving reasonable further progress, attainment, or provide for maintenance of the given NAAQS. The 

June 21, 2013 SIP submittal does not rely on reductions of VOC or NH3 from any sources in the area in 

order to demonstrate attainment. The SIP submittal does rely on SO2 emissions reductions from point 

sources; however, it does not rely on reductions from onroad SO2 sources, which represented less than 

0.2% of the total SO2 inventory for the area.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 21

Based on the emissions inventories in Tables 2-7 and 2-8, it can be concluded that:

 Onroad mobile source PM2.5 constitutes less than one percent (1%) of the area’s total 

2007 PM2.5 emissions and the area’s total projected 2014 PM2.5 emissions.

 Onroad mobile source NOx constitutes less than five percent (5%) of the area’s total NOx

emissions in 2007 and less than four percent (4%) of the area’s total projected 2014 NOx

emissions.

Therefore, with regard to the first factor to be considered by this SIP submittal for determining 

an insignificance finding, ACHD asserts that the low mobile source contribution of direct PM2.5

and NOx, in concert with their continuing decline, both in absolute emissions and relative to 

other source categories (as documented in Tables 2-7 and 2-8), warrants an insignificance 

finding for both the 1997 annual and 2006 24-hour PM2.5 standards.6

 

6 This conclusion would be consistent with EPA’s past actions on requests to find direct PM2.5 and NOx

emissions to be insignificant for transportation conformity purposes. Generally, EPA has proposed to 

approve insignificance findings if onroad NOx emissions are less than 10% of an area’s inventory and 

onroad direct PM2.5 emissions are less than 3% of an area’s total direct PM2.5 emissions inventory. 

(Percentage guidelines as provided by EPA’s Office of Transportation and Air Quality.)
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 22

2.5 Insignificance Finding Factor 2: Current State of Air Quality as Determined 

by Monitoring Data for PM2.5 in the Liberty-Clairton Area

PM2.5 monitors are currently located at eight different monitoring locations throughout 

Allegheny County. Two Federal Reference Method (FRM) PM2.5 monitors are located in the 

Liberty-Clairton area. The FRM monitor at Liberty is located atop a school at high elevation 

near the center of the Liberty-Clairton area. The FRM monitor at Clairton is located atop a 

school at low elevation in the western portion of the area. Appendix B of the June 21, 2013 SIP 

submittal contains detailed monitored data and EPA Air Quality System (AQS) reports.

Currently, monitoring data shows that the Liberty-Clairton area is attaining the 1997 annual 

PM2.5 standard. EPA has made two determinations of attainment for the 1997 PM2.5 standard for 

the Liberty-Clairton area:

7

1. The area has attained the 1997 NAAQS by its attainment date, based on 2009-2011 

monitoring data.

2. Second, the area has continued to attain the 1997 NAAQS, based on 2010-2012 

monitoring data.

The Liberty-Clairton area is currently not attaining the 24-hour 2006 NAAQS. However, the 

June 21, 2013 attainment demonstration addressed regional and local controls needed to bring 

the area into attainment for the 2006 NAAQS by 2014. Since the nonattainment problem of 

PM2.5 is primarily stationary source-based, the controls for Liberty-Clairton corresponded to 

stationary source controls.

All Allegheny County FRM8PM2.5 annual and 24-hour design values (3-year averages of annual

and 24-hour 98th-percentiles, respectively) for the timeframe 2000-2012 are shown in Figures 2-1

and 2-2.

9

 

7

Final rule published in the FR on October 25, 2013, with an effective date of November 25, 2013.

8

Initial Avalon monitored data for the period Jan. 2010 – May 2011was Federal Equivalent Method 

(FEM) before switching to FRM in June 2011.

9

Figures 2-1 and 2-2 include some 3-year periods with low recovery quarters (i.e., less than 75% valid 

data per quarter) as noted in Appendix B of the June 21, 2013 SIP submittal in regard to design values 

through 2011. Additionally, in 2012, one calendar quarter was below 75% data recovery for North 

Braddock. The technical support document for the determination of attainment for Liberty-Clairton for 

the 1997 PM2.5 NAAQS further addresses data completeness for the Liberty and Clairton monitors for 

2010-2012.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 23

Figure 2-1. PM2.5 FRM Annual Design Values, Allegheny County, 2000-2012

Figure 2-2. PM2.5 FRM 24-Hour Design Values, Allegheny County, 2000-2012

Figures 2-1 and 2-2 show that all Allegheny County sites have shown decreasing design values 

for both annual and 24-hour PM2.5 NAAQS since 2000, with only the Liberty monitor showing a 

24-hour design value above the NAAQS for the 2010-2012 period.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 24

Figures 2-3 and 2-4 show annual and 24-hour design values for the Liberty and Clairton 

monitors over a 10-year timeframe from 2005 to the projected year 2014 (projected design 

values were taken from the attainment tests in the June 21, 2013 SIP submittal).

Figure 2-3. Liberty and Clairton FRM Annual Design Values with Projected to 2014

Figure 2-4. Liberty and Clairton FRM 24-Hour Design Values with Projected to 2014
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 25

The attainment demonstration showed that the Liberty-Clairton area will continue to attain the 

1997 PM2.5 NAAQS based on decreasing annual design values and will attain the 2006 PM2.5

NAAQS by 2014 based on projected 24-hour design values. Figures 2-3 and 2-4 show that the 

decreasing trends in the modeled projections are similar and consistent with the actual monitored 

data, indicating that the projections are adequate to represent expected air quality monitoring 

data after the implementation of control measures. (For the projections, averaging periods 2006-

2008 and 2013-2015 were used to represent the weighted 2007 baseline and 2014 future 

projected design values, respectively.)

Therefore, with regard to the second factor to be considered by this SIP submittal for 

determining the acceptability of an insignificance finding, ACHD asserts that attainment of the 

1997 annual PM2.5 NAAQS beginning in 2011 and the continuing monitored and modeled 

downward trends in concentrations support an insignificance finding for that NAAQS. With 

regard to the 2006 24-hour PM2.5 NAAQS, the continuing downward trends in monitored 

concentrations and the projected attainment of the NAAQS in 2014 based on control measures in 

the June 21, 2013 SIP submittal support an insignificance finding for the 2006 24-hour PM2.5

NAAQS.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 26

2.6 Insignificance Finding Factor 3: Absence of SIP Motor Vehicle Control 

Measures

2.6.1 Transportation Control Measures

Historically, there have been no Allegheny County SIP requirements for Transportation Control 

Measures (TCMs). TCMs are strategies that reduce transportation-related air pollution, 

greenhouse gas (GHG) emissions, and fuel use by reducing vehicle miles traveled and improving 

roadway operations.

Vehicle use can be reduced through less-polluting transportation alternatives, such as public 

transit, and strategies that decrease the need for vehicle trips, such as telecommuting. TCMs 

may also focus on making travel more efficient by carefully managing the transportation system. 

2.6.2 Current Control Requirements

Onroad vehicles are subject to federal emission standards. In addition, a vehicle inspection and 

maintenance program is in place in the area, as well as vehicle idling restrictions, and low vapor 

pressure gasoline requirements during the ozone season. These controls were either required or 

selected for implementation in order to reduce emissions and to bring the larger Pittsburgh MSA

into attainment of the ozone NAAQS.

2.6.3 Review of RACM

TranSystems|E.H. Pechan (TS|Pechan), along with KB Environmental Sciences, Inc., examined 

several RACM options for onroad mobile sources in the Liberty Clairton area, as shown in Table 

2-9 below for highway sources. Additional details of the RACM analysis can be found in 

Appendix I of the June 21, 2013 SIP submittal.

Table 2-9. Onroad Highway Mobile Sources RACM Analysis Summary
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 27

The TS|Pechan RACM analysis for the Liberty-Clairton area included consideration of the 

establishment of an Employer Rideshare Program as a SIP Motor Vehicle Control Measure. It 

would provide incentives or encouragement for employers to offer a carpool/ridesharing program 

to employees. Control efficiencies for a commuter benefit program involve a reduction in the 

total vehicle miles traveled (VMT) by individuals participating in the program. The annualized 

cost-effectiveness of the proposed program is $8,542,879 per ton of PM2.5.

EPA interprets RACM as a collection of measures that, taken as a group, advance the NAAQS

attainment date by at least one year. In this instance, the finding of the analysis performed as 

part of the June 21, 2013 SIP submittal was that the set of RACMs that have been identified for 

the Liberty-Clairton PM2.5 NAA are not likely to advance the attainment date by one year or 

more. Consequently, none, including the TCM, will be implemented.

Therefore, with regard to the third factor to be considered by this SIP submittal for determining 

an insignificance finding, ACHD asserts that the absence of new motor vehicle control measures 

in the June 21, 2013 SIP submittal warrants an insignificance finding for both the 1997 and 2006

PM2.5 NAAQS.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 28

2.7 Insignificance Finding Factor 4: Historical Trends and Future Projections of 

the Growth of Motor Vehicle Emissions

Allegheny County is unique in the fact that the population has been declining since the 1960s. 

Localized regions of population growth are occurring, but the general trend for the county is one 

of negative growth. The 2010 census shows continued decrease in population in the five 

municipalities of the Liberty-Clairton area as well. According to the U.S. Census Bureau, from 

2000 to 2010, the City of Clairton had a decrease in population of about 20%, the largest 

population decrease in the nonattainment area. (See Figure 2-5 below.)

Figure 2-5. Population Trends for Allegheny County, 2000-2010

Population decreases were also seen in the remaining nonattainment area boroughs. Glassport 

saw a population change of -10.2%, Liberty -4.5%, Lincoln -12.0%, and Port Vue -10.2%. In 

total, the five nonattainment area municipalities decreased in population by 2,900 people, or -

13.4% from 2000 to 2010. This continues a trend of decline from the 1990-2000 period, which 

saw an average change in population of -6.6% in the nonattainment area. Decreasing 

populations signal less use of cars and a lesser need for school buses and other diesel-engine 

vehicles.

Section 2.3.4 above corroborates the expected slow growth in vehicle population. Table 2-4

indicates an increase of only 288 vehicles between the years 2007 and 2014. Also, as discussed 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 29

in Section 2.4 above, the attainment demonstration projects that both annual and 24-hour onroad 

emissions of direct PM2.5 and NOx will decrease from the 2007 base year through 2014.

While not a part of the June 21, 2013 SIP submittal, the most recent Southwestern Planning 

Commission (SPC) air quality conformity determination for the Pittsburgh transportation 

management area10 shows similar trends for VMT and onroad emissions. The SPC conformity 

determination projected a slow growth in VMT in the area through 2040 and a downward trend 

in onroad emissions of direct PM2.5 and NOx throughout the assessment period.

Therefore, with regard to the fourth factor to be considered by this SIP submittal for determining 

the acceptability of an insignificance finding, ACHD asserts that available data does not indicate

highway motor vehicle emissions growth that would lead to a violation of the 1997 or 2006 

PM2.5 NAAQS, and thus warrants an insignificance finding for both the 1997 and 2006 PM2.5

NAAQS.

 

10 SPC Air Quality Conformity Determination, July 2012: http://www.spcregion.org/trans_airreport.shtml
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 30

2.8 Motor Vehicle Emissions Insignificance Findings Conclusions

For the reasons set forth in Sections 2.4 through 2.7 of this document, ACHD concludes that 

Liberty Clairton area onroad emissions of PM2.5 and NOx are insignificant contributors to the 

nonattainment of the 1997 and 2006 PM2.5 NAAQS for the Liberty-Clairton area.

Upon a positive adequacy review and approval of the information included in this SIP submittal

for transportation conformity, no highway emissions analysis will be required for direct PM2.5 or 

NOx. PM2.5 hot-spot analyses would continue to apply for required projects under 40 CFR 

93.116 and 93.123(b) of the transportation conformity rule.

The Liberty-Clairton area is also subject to transportation conformity requirements for the 8-hour 

ozone standard, with SIP-approved MVEBs for NOx and VOC. Highway analysis of seasonal 

ozone precursors would continue to be mandatory.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 31

3 Projected Electric Generating Unit Emissions

This section updates and revises the projected electric generating unit (EGU) emissions analysis 

previously given in the June 21, 2013 SIP submittal, specifically the information provided in 

Section 5.3.5 and Appendix E-6.

As specified in the June 21, 2013 SIP submittal, the Cross-State Air Pollution Rule (CSAPR)

11

future case 2014 inventory was used for projected EGU emissions in the modeling 

demonstration. The Clean Air Interstate Rule (CAIR)

12 future case 2015 inventory, developed in 

2005, is an outdated inventory that may not adequately represent expected EGU emissions. The 

CSAPR future case 2014 inventory, developed in 2011, was therefore used as the more recent 

and realistic dataset for expected EGU emissions. (At the time of this supplemental SIP revision, 

CSAPR was under review by the U.S. Supreme Court.)

In addition, EGU projections have changed since development of the CSAPR inventory in 2011. 

Several units have been modified or deactivated (or proposed for deactivation) due to 

compliance issues, increased natural gas production, economic factors, and/or other reasons. 

Reductions from these controls or deactivations were not included in the SIP modeling 

demonstration.

For a look at the appropriateness of the CAIR and CSAPR inventories in relation to more recent 

data, reported 2012 SO2 and NOx emissions from EPA’s Clean Air Markets Division (CAMD)13

were examined for the CSAPR-controlled states. (Note: CAIR states are similar to CSAPR but 

do not include MN, KS, NE, OK and include MA, CT, DE.) Current or expected reductions 

were also used to extrapolate the reported the 2012 data to years 2013-2015. PA and 

surrounding states within the PJM Interconnection Regional Transmission Organization (RTO) 

territory were the focus for expected reductions.

Reductions for PA and the surrounding PJM territory include current and proposed PJM 

deactivations14 and state-permitted modifications. Some of the deactivations include units that 

are subject to federal consent decrees. Details of expected reductions within the PJM territory

are given by state and unit in Appendix A, while supporting permits, deactivation requests, and 

consent decrees are included in Appendix B.

 

11 CSAPR information: http://www.epa.gov/airtransport/CSAPR/index.html

 2014 CSAPR TR1 Remedy files: ftp://ftp.epa.gov/EmisInventory/2005v4_2/2014emis

12 CAIR information: http://www.epa.gov/airmarkets/progsregs/cair/index.html

 2015 Final CAIR Modeling: http://www.epa.gov/airmarkets/progsregs/epa-ipm/cair/index.html

13 CAMD database: http://ampd.epa.gov/ampd/ (accessed 8/21/2013)

14 PJM Interconnection: http://www.pjm.com/planning/generation-deactivation/gd-summaries.aspx

(accessed 9/12/2013). Note that a deactivation is proposed until actual deactivation date and does not 

constitute permanent retirement of a unit without further analysis. The deactivation process is explained 

in more detail in PJM Manual 14D: http://www.pjm.com/~/media/documents/manuals/m14d.ashx
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 32

Maps of CSAPR states and the PJM Interconnection territory are shown in Figures 3-1- and 3-2 

below. Appendix C contains back-trajectory data indicating the possible influence of upwind 

and surrounding states on pollution in SWPA.

Figure 3-1. CSAPR States

Figure 3-2. PJM Interconnection Territory
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 33

Table 3-1 below shows a summary of the actual/expected unit deactivations by plant capacity (in 

MW) for 2012-2015 in the PJM territory. These plants were included in the SIP modeling 

demonstration with CSAPR-allocated emissions levels for 2014. Emissions reductions per year 

from these deactivations are given in Appendix A; deactivation worksheets from the PJM web 

site are given in Appendix B-2.

Table 3-1. PJM Unit Deactivations by Plant Capacity, 2012-2015

Plant Year State Decrease in 

Capacity (MW) Plant Year State Decrease in Capacity (MW)

Albright 2012 WV 283 Riverside 2014 MD 118

Armstrong 2012 PA 343 Yorktown 2014 VA 324

Bay Shore 2012 OH 495 Ashtabula 2015 OH 244

Conesville 2012 OH 165 Bergen 2015 NJ 21

Crawford 2012 IL 532 Burlington 2015 NJ 205

Eastlake (2 units) 2012 OH 837 Clinch River 2015 VA 230

Elrama 2012 PA 460 Eastlake (3 units) 2015 OH 396

Fisk 2012 IL 326 Edison 2015 NJ 504

Kearny (2 units) 2012 NJ 250 Essex 2015 NJ 490

Niles 2012 OH 217 Gilbert 2015 NJ 188

Phil Sporn (1 unit) 2012 WV 440 Glen Lyn 2015 VA 235

Potomac River 2012 VA 482 Kammer 2015 WV 600

R. Paul Smith 2012 MD 115 Kanawha River 2015 WV 400

Rivesville 2012 WV 121 Kearny (1 unit) 2015 NJ 21

State Line 2012 IN 515 Lake Shore 2015 OH 245

W C Beckjord (1 unit) 2012 OH 94 Mercer 2015 NJ 115

Willow Island 2012 WV 189 Missouri Ave 2015 NJ 60

Hatfield's Ferry 2013 PA 1590 Muskingum River 2015 OH 790

Mitchell 2013 PA 359 O H Hutchings (5 units) 2015 OH 277

O H Hutchings (1 unit) 2013 OH 62 Phil Sporn (5 units) 2015 WV 580

Piney Creek 2013 PA 31 Picway 2015 OH 95

Schuylkill 2013 PA 166 Sewaren 2015 NJ 564

Titus 2013 PA 243 Shawville 2015 PA 597

W C Beckjord (2 units) 2013 OH 222 Tanners Creek 2015 IN 488

B L England 2014 NJ 129 W C Beckjord (3 units) 2015 OH 802

Chesapeake 2014 VA 576 Werner 2015 NJ 212

Portland 2014 PA 401
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 34

Table 3-2 below shows CAMD reported 2012 emissions for SO2 and NOx for CSAPR states 

along with extrapolated emissions for 2013-2015 based on expected controls and deactivations in 

the PJM territory. Projected emissions for future case 2014 CSAPR and 2015 CAIR are shown 

for comparison.

Table 3-2. CAMD Reported 2012 SO2 and NOx Emissions (with Expected Reductions in 

PJM Territory for 2013-2015) and Interstate Transport Rules Projected Emissions, 

CSAPR States

CAMD Reported with

Expected Reductions in PJM 

Territory (CSAPR States)

2012 

Reported 

(tons)

2013 

Expected 

(tons)

2014 

Expected 

(tons)

2015 

Expected 

(tons)

Reported (or Expected) SO2 3033582 2965809 2947442 2746660

Reported (or Expected) NOx 1350962 1332804 1311874 1291816

Interstate Transport Rules (CSAPR States) 2014 CSAPR 

(tons)

2015 CAIR 

(tons)

Projected SO2 2919042 4618909

Projected NOx 1428480 1561493

Table 3-2 shows that recent reported emissions for 2012 are already well below 2015 CAIR 

levels for both SO2 and NOx, suggesting that the CAIR projections as developed in 2005 may be 

inaccurate. Additionally, 2012 NOx emissions are already below the 2014 CSAPR projected 

level.

Expected reductions through 2014 from the PJM territory alone (without additional reductions in 

other states) show that SO2 is within 1% of the 2014 CSAPR projection. Expected reductions 

through 2015 continue to decrease to below the 2014 CSAPR projection for SO2.

These reductions are also shown visually on the following page in Figures 3-3 and 3-4, using 

long-term trends for CAMD SO2 and NOx emissions over the timeframe 2007-2015. Year 2007 

was used as the baseline year for the modeling demonstration with 2014 as the future projected 

year. Expected/projected years are shown indicated by dotted lines in the figures.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 35

Figure 3-3. Long-Term Reported and Expected/Projected SO2 (tons), CSAPR States

Figure 3-4. Long-Term Reported and Expected/Projected NOx (tons), CSAPR States
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 36

The long-term trends in Figures 3-3 and 3-4 show that reported CAMD emissions of SO2 and 

NOx have decreased significantly in the U.S. in recent years. Reductions will continue through 

2014 and 2015 using anticipated controls and deactivations for the PJM territory. Controls, fuel 

switches, and deactivations from other states have been excluded from this analysis, resulting in 

a potentially conservative approach for estimating future emissions.

Table 3-3 below shows a summary of the federal consent decrees and corresponding SO2 actions 

and limits that are applicable to units in PJM states.

Table 3-3. Federal Consent Decrees for Units in PJM states

Company State Plant

Date of 

Consent 

Decree

Action Required15 System-Wide SO2 Limits

American 

Electric Power 

(AEP) Corp.

Ohio/ West 

Virginia/ 

Indiana/ 

Kentucky/ 

Virginia

Amos October 

2007

Install FGD by 2011 2014: 340,000 tons/year

2019 (continuing in 

perpetuity): 174,000 

tons/year

Big Sandy Install FGD by 2016 (1 

unit), meet coal sulfur 

content limit (1 unit)

Cardinal Install FGD by 2009 (2 

units) and 2013 (1 unit)

Conesville Install/upgrade FGD by 

2011 (3 units), 

retire/repower/retrofit by 

2013 (3 units)

Gavin Install FGD by 2008

Glen Lyn Meet coal sulfur content 

limit by 2008

Kanawha Meet coal sulfur content 

limit by 2008

Mitchell Install FGD by 2008

Mountaineer Install FGD by 2008

Muskingum Retire/repower/retrofit by 

2016 (4 units), install 

FGD by 2016 (1 unit)

Rockport Install FGD by 2018 (1 

unit) and 2020 (1 unit)

Sporn Retire/repower/retrofit by 

2014 (1 unit)

Tanners Creek Meet coal sulfur content 

limit by 2008

Various (for total 

of 600 MW)

Retire/repower/retrofit by 

2019 (for 600 MW 

reduction from 13 units)

American 

Municipal 

Power

Ohio Gorsuch May 2010 Retire by 2013 n/a

Dominion 

Energy

Illinois/ 

Indiana 

State Line April 

2013

Retire (2 units) by mid2012, retire (2 units) by 

mid-2013

2014: 8,500 tons/year

 

15 FGD is Flue Gas Desulfurization; DSI is Dry Sorbent Injection; ECO is Electro-Catalytic Oxidation
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 37

Company State Plant

Date of 

Consent 

Decree

Action Required15 System-Wide SO2 Limits

Brayton Point Meet emission rates for 

existing FGD by mid2013

Kincaid Install DSI by 2014 

Duke Energy Indiana Gallagher December 

2009

Retire/repower by 2013 

(2 units), install DSI by 

2011 (2 units) 

n/a

Dynegy Illinois/ 

Indiana

Baldwin March 

2005

Install FGD by 2013 2013 (continuing in 

perpetuity): 29,000 

tons/year Havana

Hennepin Reduce SO2 emissions by 

Vermillion 2006

Wood River

East Kentucky 

Power 

Cooperative

Kentucky Cooper July 2007 Retire by 2013, repower 

by 2014, or install FGD 

by mid-2018

2013: 28,000 tons/year

Dale

Spurlock Install FGD by 2009 (1 

unit) and 2011 (1 unit)

Hoosier 

Energy Rural 

Electric 

Cooperative

Indiana Merom July 2010 Upgrade FGD by mid2012 (1 unit) and mid2013 (1 unit)2014: 26,000 tons/year

Ratts Retire/repower by 2017 

or meet emission rates by 

2016

Kentucky 

Utilities

Kentucky Brown February 

2009

Install FGD by 2011 2011: 2,300 tons/year

Northern 

Indiana Public 

Service 

Company 

Indiana Bailly January 

2011 

Upgrade existing FGD by 

2014

2019: 11,600 tons/year (if 

Michigan City unit gets 

FGD) or 10,200 tons/year 

(if Michigan City unit gets 

retired)

Dean Mitchell Retire by 2010

Michigan City Retire or install FGD by 

2019

Schahfer Install FGD (2 units) by 

2014/2016 and upgrade 

FGD (2 units) by 2011

Ohio Edison/ 

FirstEnergy 

Corporation

Ohio Burger March 

2005 and 

August 

2009

Retire by 2011 or repower 

by 2013

2011: 29,900 tons/year 

(only for Sammis Plant)

Sammis Install FGD, Flash Dry 

Absorber, ECO, or Induct 

Scrubber at various units 

by 2011

Mansfield Upgrade FGD by 2008

PSEG Fossil 

Corp.

New Jersey Hudson January 

2006

Install FGD by 2010 2010: 5,270 tons/year

Mercer

Tennessee 

Valley 

Authority

Kentucky Paradise April 

2011

Upgrade FGD (2 units) by 

2013 and Install Wet 

FGD (1 unit) by mid2011

2019: 110,000 tons/year

Shawnee Install FGD, repower to 

renewable biomass, or 

retire by 2018
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 38

Supporting EGU documentation (permits, deactivations, consent decrees) can be found in

Appendix B.

Considering the comparisons to CAIR and reported/extrapolated CAMD data, the 2014 CSAPR 

remedy case is an adequate inventory of expected EGU emissions for modeling purposes.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 39

4 Legal Documents

4.1 Notice of Public Hearing and Comment Period
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 40

4.2 Transmittals of Hearing Notice to PA DEP and EPA
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 41
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 42

4.3 Proof of Publication and Certification of Public Hearing
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 43
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 44

4.4 Summary of Public Comments and Responses

Comment and Response Document for the Proposed SIP Revision 75

Revision to State Implementation Plan for PM2.5 for Allegheny County

Supplement to the Liberty-Clairton PM2.5 Attainment Plan, 2006 NAAQS

December 18, 2013 Public Hearing

Public Comment Period ending December 23, 2013

EGU ANALYSIS

Comments related to the projected emissions for electric generating units (EGUs).

1. Comment: ACHD cannot rely on controls and emission reductions anticipated from the 

implementation of the Cross-State Air Pollution Rule (CSAPR). The Clean Air Act requires 

that an attainment demonstration contain specific, federally-enforceable measures that will 

attain the NAAQS. The CSAPR future case inventory for 2014 assumes emission controls 

and reductions associated with a vacated law that is under review by the U.S. Supreme Court; 

CSAPR is therefore not legally enforceable and not an appropriate inventory for 

representative purposes. Any emission reductions, including those represented in future case 

modeling demonstrations, should instead be derived from the Clean Air Interstate Rule 

(CAIR) pending the final decision regarding CSAPR or promulgation of another replacement 

rule.

Commenter: Clean Air Council, PennFuture, Clean Water Action.

Response: As noted in the May 10, 2013 SIP document, ACHD will rely on CAIR, state, 

and permit controls until a final decision is made regarding CSAPR or until a replacement 

rule is promulgated. However, ACHD believes that the inventory used in the CAIR 

modeling demonstration is an outdated inventory that does not adequately represent future 

emissions from the electric generating unit (EGU) sector for modeling purposes. The 

CSAPR future case inventory was therefore used in the modeling demonstration. ACHD 

maintains that, in lieu of any additional inventory, the CSAPR inventory is an updated 

version of the CAIR inventory that is best representative of expected EGU controls.

The purpose of the additional analysis of projected EGU emissions in the supplemental SIP 

was to further clarify “real-world” emissions reductions and how they compare to CSAPR 

and CAIR inventories. The analysis of recent emissions, including current and expected 

deactivations not included in the modeling, show that reported and expected emissions for 

CSAPR states are comparable to the emissions included in the CSAPR 2014 modeling. EGU 

deactivations/retirements that are federally-enforceable have been noted in Table 3-3 and in 

Appendix A of the Supplemental SIP.

Furthermore, EPA modeling guidance outlined the methodology for the use of actual 

emissions with the intent of predicting realistic transformation of precursor emissions to 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 45

PM2.5 concentrations from all emissions sectors. The CAIR emissions, while representing 

the current enforceable emissions allocations, would not lead to realistic estimations of future 

PM2.5 concentrations.

2. Comment: EGU emissions from CSAPR modeled in the attainment demonstration are 

smaller than those in the CAIR inventory. Table 3-2 of the November 2013 Supplemental 

SIP indicates that total 2014 CSAPR-modeled emissions for the CSAPR states are 2,919,042 

tons of sulfur dioxide (SO2) and 1,428,480 tons of nitrogen oxides (NOx). These CSAPR 

emissions are substantially lower than the 2015 CAIR emissions, namely 4,618,909 tons of 

SO2 and 1,561,493 tons of NOx. Thus, SO2 emissions from CSAPR are 37% lower than the 

CAIR emissions. These CSAPR SO2 emissions are also slightly smaller than the 2014 

emissions (2,947,442 tons) that have been estimated from the CAMD database. NOx

emissions from CSAPR are 9% lower than the CAIR emissions. Thus, large differences in 

CAIR and CSAPR emissions, especially for SO2, raise serious questions about the validity of 

the SIP attainment demonstration.

Commenter: Clean Air Council, PennFuture, Clean Water Action.

Response: Similar to the response to comment 1, the purpose of the EGU analysis in the 

Supplemental SIP was to provide a quantitative comparison of real-world emissions to 

modeling inventory emissions. The large differences in the CAIR and CSAPR emissions 

support the circumvention of the CAIR inventory for the modeling demonstration. The 

CSAPR 2014 SO2 inventory is within 1% of the expected CAMD 2014 SO2 inventory, while 

the CAIR 2015 inventory is 68% higher than the expected CAMD 2015 SO2 inventory. 

Additionally, reported NOx emissions in 2012 were already lower than both 2014 CSAPR 

and 2015 CAIR. The expected emissions analysis also includes deactivations from PJM 

Interconnection states only and does not include unannounced controls, fuel switches,or 

deactivations, leading to a potentially conservative approach to the emissions analysis. The 

CSAPR inventory therefore better represents actual emissions from the power sector than 

CAIR.

3. Comment: CAIR projections (with higher EGU emissions) provide an additional safety 

margin for ambient standard attainment since the CAMx photochemical model is known to 

largely underestimate PM2.5 concentrations and the 2014 CAMx-projected concentrations 

(34-35 μg/m3) are barely below the ambient 24-hour standard of 35 μg/m3.

Commenter: Clean Air Council, PennFuture, Clean Water Action.

Response: The CAMx model was sufficiently accurate for this type of demonstration, 

achieving model performance goals for PM2.5 for the baseline year. Furthermore, EPA 

recognizes limitations in air quality models, and procedures in the EPA modeling guidance 

delineated the use of relative response factors (RRFs) in the attainment tests in order to 

minimize modeled uncertainties. Modeled results are used to scale the observed weighted 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 46

PM2.5 species concentrations to project 2014 future year PM2.5 concentrations. If the model 

underestimates for the baseline year, it also underestimates for the future projected year. 

Thus, modeled underestimation or overestimation bias does directly equate to projected 

concentrations since the modeled results are used in the relative sense.

Additionally, preliminary monitored data for 2013 indicates that attainment of the 24-hour 

standard may be occurring earlier than expected. Unofficial federal reference method (FRM) 

monitor results show that Liberty is below the 24-hour standard for 2013 (98th-percentile 

conc. = 31.1 μg/m3). Thus, monitored data may be showing better results than as projected 

with the modeling, indicative of a conservative modeling effort.

4. Comment: SO2 emissions from Pennsylvania EGUs in the CSAPR are lower than those in 

the CAIR and CAMD inventories. Appendix A of the November 2013 Supplemental SIP

shows that SO2 emissions from EGUs located in Pennsylvania are 125,545 tons for CSAPR

in 2014, 150,093 tons for CAIR in 2015, and 225,612 tons for CAMD with expected 

reductions in 2014. Thus, the CSAPR SO2 emissions that were modeled in the attainment 

demonstration are substantially lower than those from CAIR and CAMD. These EGUs are 

located closest to the Liberty-Clairton area and, hence, are expected to heavily influence the 

PM2.5 concentrations in the area.

Commenter: Clean Air Council, PennFuture, Clean Water Action.

Response: The discrepancy between PA CSAPR and expected CAMD SO2 2014 emissions 

is largely due to Homer City power plant emissions, where the expected emissions are 82,439 

tons higher than modeled. Completion of installation of the pollution control equipment at 

Homer City has been extended to early 2015. While Homer City may contribute to 

background sulfate concentrations in Western PA, the back-trajectory analysis in Appendix C 

shows that the majority of the high sulfate concentrations at Liberty occur on days when 

transport is from the Midwest or the Ohio Valley. Additionally, local PM2.5 impacts are 

highest when winds are from the southwest (upwind of the area). The Homer City plant lies 

36 miles downwind (northeast) of the Liberty-Clairton area and is unlikely to contribute to 

the high concentrations that are causing nonattainment in the Liberty-Clairton area. The 

focus of the EGU analysis was reductions within the PJM territory as a whole, with the 

highest presumed contributions from upwind EGUs to the west and southwest.

5. Comment: High PM2.5 concentrations are influenced by emissions in surrounding states. 

Backward trajectories in Appendix C of the November 2013 Supplemental SIP indicate that 

high PM2.5 concentrations observed in 2012 are heavily influenced by emission sources 

located in upwind/surrounding states. These emission sources are beyond the ACHD 

jurisdiction and are not subjected to ACHD control. This analysis provides additional strong 

evidence that higher emissions in the CAIR should be used in attainment demonstration.

Commenter: Clean Air Council, PennFuture, Clean Water Action.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 47

Response: Similar to the response to comment 4, expected emissions from states within the 

PJM territory were the focus of the emissions analysis. (Note that PJM includes only 

portions of IN, IL, KY, and MI, so not all of the deactivations in these states have been 

accounted for in the analysis, leading to a conservative effort.) The reductions in these states, 

although outside of ACHD’s jurisdiction, were based on announced PJM deactivations and 

federal consent decrees.

6. Comment: The CAMD data are biased by large reduction in electricity demand due to 

economic recession. Figures 3-3 and 3-4 of the November 2013 Supplemental SIP show 

large drops in SO2 and NOx emissions reported in the CAMD database between 2007 and 

2012. These emission reductions are primarily due to the large reduction in power demand 

caused by the current economic recession starting in 2008. Power demand and emissions 

may increase again following the termination of the current recession. Thus, the CAMD 

emissions may not be reliable for making long-term projections.

Commenter: Clean Air Council, PennFuture, Clean Water Action.

Response: As shown in Figure 5-7 of the May 10, 2013 SIP document, heat input data from 

CAMD show rather steady EGU production levels after the height of the low-production 

levels in 2009 due to the recession. Continued decreases in EGU emissions are more likely 

attributable to deactivations due to environmental compliance, increased natural gas 

production, and other factors. The known and expected reductions included in the EGU 

analysis were based on announced deactivations and federal consent decrees, irrespective of 

electricity demands.

7. Comment: It was discovered during the public comment period of the supplemental SIP that 

the ethanol percentages in the model had not been revised to the newer methodology used by 

PA DEP. The fuel assumptions in the MOVES modeling used 0.00% ethanol in summer 

RVP months and 6.78% ethanol in winter months for both baseline and future modeled cases. 

The newer methodology, as recommended by EPA in mid-2012, uses 0.00% ethanol yearround for years up through 2009 and 10% ethanol year-round after 2009. However, 

considering the low mobile source emissions for the Liberty-Clairton area, any revision in the 

baseline or future case ethanol percentages would show negligible changes in the overall 

insignificance finding.

Commenter: Jayme Graham, Allegheny County Health Department.

Response: No response necessary.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 48

Notes on commenters:

 Comments received jointly from Clean Air Council, Citizens for Pennsylvania’s Future 

(PennFuture), and Clean Water Action were signed by the following: 

o Joseph Otis Minott, Esq., Executive Director, Clean Air Council

o Tom Hoffman, Western Pennsylvania Director, Clean Water Action

o Heather Langeland, Esq., Staff Attorney, PennFuture

Contributing to these comments, on behalf of Clean Air Council, included the 

following:

o Khanh Tran, Principal, AMI Environmental

 Additional comment made by Jayme Graham, Acting Manager, Air Quality Program, 

Allegheny County Health Department.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 49

4.5 Certification of Adoption
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds., Supp. May 2014 Page 50

References

Allegheny County Health Department (ACHD) (2013). Proposed Revision to the Allegheny 

County Portion of the Pennsylvania State Implementation Plan: Attainment Demonstration for 

the Liberty-Clairton PM2.5 Nonattainment Area 2006 Standards. ACHD: Pittsburgh, PA, May 

10. http://www.achd.net/air/pubs/SIPs/Liberty-ClairtonPM25SIP2006Stds_FINAL.pdf

Michael Baker Jr., Inc. (2005). “Statistical Evaluation of Projected Traffic Growth, Traffic 

Growth Forecasting System: Final Report,” March 14, 2005.

Page, S. D. (2012). “Implementation Guidance for the 2006 24-Hour Fine Particle (PM2.5) 

National Ambient Air Quality Standards (NAAQS).” Memorandum. U.S. EPA, Office of Air 

Quality Planning and Standards. March 2. Available at: 

http://www.epa.gov/ttn/naaqs/pm/pdfs/20120302_implement_guidance_24-hr_pm2.5_naaqs.pdf

TranSystems|E.H. Pechan & Associates, Thompson G. Pace, and Michael Baker Jr. Inc. (2012). 

2007 and 2014 Liberty-Clairton PM2.5 Nonattainment Area Emission Inventories and Source 

Assessment Analysis. Prepared for Allegheny County Health Department.

U.S. EPA (2006). Area Designations for 2006 24-Hour PM2.5 NAAQS – Technical Information

web page: http://www.epa.gov/ttn/naaqs/pm/pm25_2006_techinfo.html

U.S. EPA (2005). Emissions Inventory Guidance for Implementation of Ozone and Particulate 

Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations. EPA454/R-05-001. August, updated November. Available at: 

http://www.epa.gov/ttnchie1/eidocs/eiguid/index.html

U.S. EPA (1992). “State Implementation Plans; General Preamble for the Implementation of 

Title I of the Clean Air Act Amendments of 1990,” Proposed Rule, 57 Federal Register 

13,498. Information at: http://www.epa.gov/airquality/urbanair/sipstatus/index.html

U.S. EPA, Region III (2008). Designation Response Letter to the Honorable Edward G. Rendell, 

and Addendum 2. Available at: 

http://www.epa.gov/pmdesignations/2006standards/rec/region3R.htm