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

Allegheny County Health Department

Air Quality Program

May 10, 2013
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page - 2 -

{This page left blank for printing purposes}
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page i

TABLE OF CONTENTS

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

2 Problem Statement................................................................................................................ 4

2.1 Introduction ...................................................................................................................... 4

2.2 Location and Topography ................................................................................................ 4

2.3 Meteorology ..................................................................................................................... 6

2.4 Monitored Data ................................................................................................................ 8

2.5 Speciation Data Analysis ............................................................................................... 10

3 Control Strategy.................................................................................................................. 13

3.1 Interstate Transport Rules for EGUs.............................................................................. 13

3.2 U. S. Steel Mon Valley Works....................................................................................... 15

3.3 Source Shutdowns Adjacent to Liberty-Clairton ........................................................... 16

3.4 Regional Inventory Controls.......................................................................................... 16

4 Emissions Inventory............................................................................................................ 17

5 Modeling .............................................................................................................................. 19

5.1 Design and Modeling Protocol....................................................................................... 19

5.2 Emissions/Modeling Assistance..................................................................................... 19

5.3 Methodology .................................................................................................................. 21

5.3.1 Models Selection..................................................................................................... 21

5.3.2 Local Source Treatment.......................................................................................... 21

5.3.3 Modeling Domains.................................................................................................. 24

5.3.4 Modeled Inventories ............................................................................................... 26

5.3.5 Projected EGU Inventories..................................................................................... 28

5.4 Modeled Impacts............................................................................................................ 33

5.5 Model Performance ........................................................................................................ 38

6 Attainment Tests................................................................................................................. 40

6.1 Monitored Data Assumptions ........................................................................................ 40

6.2 Annual Attainment Test Methodology........................................................................... 41

6.3 24-Hour Attainment Test Methodology......................................................................... 43

6.4 Annual Attainment Test Results .................................................................................... 44

6.5 24-Hour Attainment Test Results................................................................................... 48

6.6 Unmonitored Area Analysis........................................................................................... 52

7 Reasonably Available Control Technology and Measures.............................................. 53
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page ii

8 Contingency Measures........................................................................................................ 60

9 Weight of Evidence ............................................................................................................. 62

9.1 Liberty-Clairton Monitored Data Trends....................................................................... 62

9.2 Local Major Source Modifications ................................................................................ 63

9.3 EGU Deactivations......................................................................................................... 64

9.4 Population Trends .......................................................................................................... 65

9.5 Wood Stoves and Wood-Fired Boilers........................................................................... 66

9.5.1 Wood Stoves........................................................................................................... 66

9.5.2 Outdoor Wood-Fired Boilers.................................................................................. 66

9.6 Diesel Campaign ............................................................................................................ 67

9.6.1 Idling....................................................................................................................... 67

9.6.2 City Legislation & Industry Initiatives................................................................... 68

9.6.3 ACHD/Heinz Endowment Retrofit Project ............................................................ 68

9.6.4 Federally Funded Competitive ARRA Clean Diesel Retrofit Projects................... 69

9.6.5 State Allocation Diesel Retrofit Project.................................................................. 69

9.6.6 ACHD Clean Air Fund Retrofits ............................................................................ 70

9.7 Monitored Data During Low Production Periods.......................................................... 71

10 Emergency Episodes........................................................................................................... 76

11 Legal Documents................................................................................................................. 77

11.1 Notice of Public Hearing and Comment Period ......................................................... 77

11.2 Transmittals of Hearing Notice to PA DEP and EPA ................................................ 78

11.3 Proof of Publication and Certification of Public Hearing .......................................... 80

11.4 Summary of Public Comments and Responses.......................................................... 82

11.5 Certification of Adoption.......................................................................................... 102

References.................................................................................................................................. 103

List of Tables................................................................................................................................ iii

List of Figures............................................................................................................................... iv

List of Appendices..........................................................................................................................v

Acronyms and Abbreviations ..................................................................................................... vi
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page iii

LIST OF TABLES

Table 4-1. Baseline 2007 Emissions (Tons/Year) .................................................................... 18

Table 4-2. Future Projected 2014 Emissions (Tons/Year) ..................................................... 18

Table 5-1. Local Sources for PiG and PSAT Treatment........................................................ 22

Table 5-2. 2007 Baseline Case Inventories by Region ............................................................ 26

Table 5-3. 2014 Future Case Inventories by Region............................................................... 27

Table 5-4. SWPA Modeled Emissions Reductions, Point/Area/Nonroad, 2007 to 2014...... 28

Table 5-5. CAIR 2015, CSAPR 2014, and CAMD 2012 SO2 and NOx Emissions ............... 29

Table 5-6. CAIR 2015, CSAPR 2014, and CAMD 2012 SO2 and NOx Emissions adjusted 

for PA and Surrounding State Expected Reductions 2013 to mid-2015............. 32

Table 5-7. Liberty Quarterly Modeled Averages (μg/m3) ...................................................... 34

Table 5-8. Liberty Quarterly High Day Modeled Averages (μg/m3)..................................... 35

Table 5-9. Clairton Quarterly Modeled Averages (μg/m3)..................................................... 36

Table 5-10. Clairton Quarterly High Day Modeled Averages (μg/m3) ................................. 37

Table 5-11. Statistics for the Modeled Daily Liberty Averages Compared to the Liberty 

FRM Values, Year-Round and by Season, 2007................................................... 38

Table 6-1. Liberty Annual Attainment Test, by Total Species.............................................. 44

Table 6-2. Liberty Annual Attainment Test, by Regional/Local Species.............................. 45

Table 6-3. Clairton Annual Attainment Test, by Total Species............................................. 46

Table 6-4. Clairton Annual Attainment Test, by Regional/Local Species............................ 47

Table 6-5. Liberty 24-Hour Attainment Test, by Total Species ............................................ 48

Table 6-6. Liberty 24-Hour Attainment Test, by Regional/Local Species............................ 49

Table 6-7. Clairton 24-Hour Attainment Test, by Total Species........................................... 50

Table 6-8. Clairton 24-Hour Attainment Test, by Regional/Local Species.......................... 51

Table 7-1. RACT/RACM and Alternatives Considered for the Liberty-Clairton Area ..... 56

Table 8-1. Calculation of Required and Excess Emission Reductions.................................. 60

Table 8-2. Contingency Measures Emission Reductions........................................................ 61

Table 9-1. EGU Deactivations in 2012, PA and Surrounding States .................................... 64

Table 9-2. PM2.5 FRM Quarterly Averages, 2005-2008 and 2009 ......................................... 74
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page iv

LIST OF FIGURES

Figure 2-1. Map of the Liberty-Clairton Area within the Pittsburgh-Beaver Valley Area........... 5

Figure 2-2. Wind Frequency and Speed, PM2.5 Concentration (TEOM Measurements), and 

Temperature Roses for the Liberty Monitoring Site, 2007.......................................... 8

Figure 2-3. PM2.5 FRM/FEM Annual Design Values, Allegheny County, 2000-2011................ 9

Figure 2-4. PM2.5 FRM/FEM 24-Hour Design Values, Allegheny County, 2000-2011 .............. 9

Figure 2-5. 24-Hour PM2.5 Concentrations, 2007 Baseline Year, Liberty and Average of Other 

Allegheny County Sites............................................................................................. 10

Figure 2-6. Tri-State Major PM2.5 Species Concentrations ........................................................ 11

Figure 2-7. Localized Excess at Liberty, by Species Composition ............................................ 12

Figure 3-1. Expected Coal-Fired Power Plants Controls for SO2 and NOx by 2014.................. 14

Figure 3-2. Tri-State Expected Coal-Fired Power Plants Controls for SO2 and NOx by 2014... 14

Figure 5-1. Aerial Map of Local Sources for PiG and PSAT Handling ..................................... 23

Figure 5-2. 36/12/4/0.8 km Modeling Domains ......................................................................... 24

Figure 5-3. 12/4/0.8 km Modeling Domains............................................................................... 25

Figure 5-4. Initial 4/0.8 km Modeling Domains......................................................................... 25

Figure 5-5. Reported CAMD SO2 Emissions (tons), CSAPR States, 2003-2012 ...................... 30

Figure 5-6. Reported CAMD NOx Emissions (tons), CSAPR States, 2003-2012...................... 30

Figure 5-7. Reported CAMD Heat Inputs (MMBtu), CSAPR States, 2003-2012...................... 31

Figure 5-8. Liberty and Clairton Nearby Receptors ................................................................... 33

Figure 5-9. Liberty Daily Soccer Plot, Baseline 2007 ................................................................ 39

Figure 9-1. Liberty and Clairton FRM Annual Design Values, with Trend Lines Extrapolated to 

2014 ........................................................................................................................... 62

Figure 9-2. Liberty and Clairton FRM 24-Hour Design Values, with Trend Lines Extrapolated 

to 2014 ....................................................................................................................... 63

Figure 9-3. Population Trends for Allegheny County, 2000-2010............................................. 65

Figure 9-4. Long-Term Hourly PM2.5 TEOM Averages at Liberty and Lawrenceville, 2000-

2008 ........................................................................................................................... 71

Figure 9-5. Hourly 2009 PM2.5 TEOM Averages at Liberty Compared to Long-Term 2000-2008 

Averages.................................................................................................................... 72

Figure 9-6. Hourly 2009 PM2.5 TEOM Averages at Lawrenceville Compared to Long-Term 

2000-2008 Averages.................................................................................................. 73

Figure 9-7. Hourly 2009 PM2.5 TEOM Average Differences Between Liberty and 

Lawrenceville Compared to Long-Term 2000-2008 Data ........................................ 75
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page v

LIST OF APPENDICES

Appendix A: Meteorological Analyses

A-1: Investigation of Extended, Consecutive High PM2.5 Days

A-2: Sullivan, 2007, Excerpt of Liberty-Clairton Area Meteorological Evaluation

A-3: Sullivan, 1996, Excerpt of Liberty-Clairton Area Meteorological Evaluation

Appendix B: Monitored Data

Appendix C: Speciation and Source Apportionment Analyses 

C-1: PM2.5 Speciation Data Analysis

C-2: Positive Matrix Factorization (PMF) Analysis

Appendix D: Liberty-Clairton Emissions Inventories

D-1: Stationary Point Sources

D-2: Area Sources

D-3: Nonroad Sources

D-4: Mobile Sources

Appendix E: Inventory Documentation

E-1: MANE-VU Emissions Inventory TSD 2007 Baseline Case

E-2: MANE-VU Emissions Inventory TSD 2017/2020 Projections

E-3: LADCO and SEMAP 2007 Summaries

E-4: National Emissions Inventory (NEI) 2008 Version 2 TSD

E-5: Transport Rule (CSAPR) Emissions Inventory TSD

E-6: Comparison of EGU Emissions

Appendix F: Inventory Revisions

F-1: Liberty-Clairton Emission Inventories and Source Assessment Analysis

F-2: Local Inventory Revisions 2007/2014

F-3: Regional 2014 Interpolations/Projections

Appendix G: Modeling Documentation

G-1: Modeling Protocol for Liberty-Clairton Area

G-2: Baseline Case 2007 Model Performance

G-3: ENVIRON Air Quality Modeling TSD

Appendix H: Attainment Tests

H-1: Annual Standard Attainment Tests

H-2: 24-Hour Standard Attainment Tests

Appendix I: RACT/RACM Analysis
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page vi

ACRONYMS AND ABBREVIATIONS

ACHD Allegheny County Health Department

AERMOD American Meteorological Society/Environmental Protection Agency 

Regulatory Model

AQS Air Quality System (EPA)

BACT Best Available Control Technology

CAA Clean Air Act

CAIR Clean Air Interstate Rule

CAMD Clean Air Markets Division

CAMx Comprehensive Air quality Model with extensions

CFR Code of Federal Regulations

CSAPR Cross-State Air Pollution Rule

CSN Chemical Speciation Network

CTG Control Technique Guidelines

CTM Chemical (or Chemistry) Transport Model

DON Degree of Neutralization

EC Elemental Carbon

EGU Electric Generating Unit

EPA The United States Environmental Protection Agency

ERC Emission Reduction Credit

FMVCP Federal Motor Vehicle Control Program

FLM Federal Land Managers

FR Federal Register

FRM Federal Reference Method monitor

FEM Federal Equivalent Method monitor

LADCO Lake Michigan Air Directors Consortium

L-C Liberty-Clairton

LPM Local Primary Material

MACT Maximum Achievable Control Technology

MANE-VU Mid-Atlantic/Northeast Visibility Union

MARAMA Mid-Atlantic Regional Air Management Association

MATS Modeled Attainment Test Software

MFB Mean Fractional Bias

MFE Mean Fractional Error

MOVES Motor Vehicle Emission Simulator model

MPO Metropolitan Planning Organization

MSA Metropolitan Statistical Area

MW Megawatt

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

NH4 Ammonium Ion
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page vii

NO3 Nitrate Ion

NOx Oxides of Nitrogen

OC Organic Carbon

OCMmb Organic Carbonaceous Mass by Mass Balance

OPP Other Primary PM2.5

OTC Ozone Transport Commission

PA DEP Pennsylvania Department of Environmental Protection

PBW Particle Bound Water 

PennDot Pennsylvania Department of Transportation

PiG Plume-in-Grid model

PIT Pittsburgh International Airport

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

PMF Positive Matrix Factorization model

POA Primary Organic Aerosol

PSAT Particulate Source Apportionment Technology

RACM Reasonably Available Control Measure

RACT Reasonably Available Control Technology

RFP Reasonable Further Progress

RPO Regional Planning Organization 

RRF Relative Response Factor

RVP Reid Vapor Pressure

SANDWICH Sulfate, Adjusted Nitrate, Derived Water, Inferred Carbonaceous Material 

Balance Approach

SIP State Implementation Plan

SMAT Speciated Modeled Attainment Test

SMOKE Sparse Matrix Operator Kernel Emissions System

SOA Secondary Organic Aerosol

SO2 Sulfur Dioxide

SO4 Sulfate Ion

SOx Sulfur Oxides

SPC Southwestern Planning Commission

SWPA Southwestern Pennsylvania

TOA Total Organic Aerosol

TR Transport Rule

TEOM Tapered-Element Oscillating Microbalance monitor

TPY Tons Per Year (or Tons/Year) of pollutant emissions

TSD Technical Support Document

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

USGS United States Geological Survey

VMT Vehicle Miles Traveled

VOC Volatile Organic Compound

WRF Weather Research and Forecasting model
{This page left blank for printing purposes}
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 1

1 Executive Summary

Particulate matter is a mixture of microscopic solids and liquid droplets suspended in air that 

include: acid salts (such as nitrates and sulfates), organic chemicals, metals, soil or dust particles, 

and allergens (such as fragments of pollen or mold spores). Fine particle pollution or PM2.5

describes particulate matter that is less than or equal to 2.5 micrometer (μm, or micron) in 

diameter, approximately 1/30th the diameter of a human hair.

Health studies have shown a significant association between exposure to fine particles and 

premature death from heart or lung disease. Fine particles can aggravate heart and lung diseases 

and have been linked to effects such as cardiovascular symptoms, cardiac arrhythmias, heart 

attacks, respiratory symptoms, asthma attacks, and bronchitis. These effects can result in 

increased hospital admissions, emergency room visits, absences from school or work, and 

restricted activity days. Individuals that may be particularly sensitive to fine particle exposure 

include people with heart or lung disease, older adults, and children.

In 1997, the United States Environmental Protection Agency (EPA) promulgated PM2.5 national 

ambient air quality standards (NAAQS) of 15.0 μg/m3 on an annual basis and 65 μg/m3 on a 24-

hour basis. The annual standard is based on a long-term average of concentrations, while the 24-

hour standard is based on 98th-percentile values of maximum daily concentrations.1

On December 18, 2006, a revised 24-hour PM2.5 NAAQS became effective. The United States 

Environmental Protection Agency (EPA) published air quality designations for the PM2.5

standard based on air quality monitoring data from 2006-2008 in the Federal Register on 

November 13, 2009, effective on December 14, 2009.2 On that date, areas were designated as 

being either in or out of attainment of the revised 24-hour PM2.5 NAAQS.

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

nonattainment area called the Pittsburgh-Beaver Valley area, consisting of Beaver, Butler, 

Washington, and Westmoreland counties, along with portions of Allegheny, Armstrong, Greene, 

and Lawrence counties.

One portion of southeastern Allegheny County, the Liberty-Clairton area, was designated as a 

separate nonattainment area within the larger Pittsburgh-Beaver Valley area. The LibertyClairton nonattainment area consists of the boroughs of Glassport, Liberty, Lincoln, Port Vue, 

and the city of Clairton. Liberty-Clairton monitored data and other designation factors indicated

that a more focused strategy for emission control was required for this particular area.

By December 14, 2012, three years after the effective date of nonattainment designations, State 

Implementation Plans (SIPs) for nonattainment areas are due to the U.S. Environmental 

Protection Agency (EPA). These SIPs must demonstrate that, by December 14, 2014, 

nonattainment areas under the state/local agency’s jurisdiction will be in attainment of the new 

 

1 NAAQS are given in CFR Title 40 Part 50: http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&tpl=/index.tpl

2 EPA Region III designations: http://www.epa.gov/pmdesignations/2006standards/final/region3.htm
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 2

standard. This SIP provides a control strategy and attainment demonstration of the 2006 PM2.5

standards for the Liberty-Clairton nonattainment area.

Based on 2006-2008 monitored data, PM2.5 design values for the Liberty-Clairton area were 18.3 

μg/m3 on an annual basis and 53 on a 24-hour basis. Modeling for this SIP shows attainment of 

the 15.0 μg/m3 and 35 μg/m3 standards for future case year 2014.

The primary control measures that enable the Liberty-Clairton area to demonstrate attainment of 

the PM2.5 NAAQS include:

 Interstate transport rules issued by EPA to reduce upwind transport of PM2.5 precursors

from power plants

 Upgrades and shutdowns to United States Steel Corporation’s (U. S. Steel) Mon Valley 

Works – Clairton Plant

All other controls included in the attainment demonstration are as developed for Regional 

Planning Organization (RPO) emission inventories, such as the MANE-VU (MidAtlantic/Northeast Visibility Union) inventory for Mid-Atlantic and Northeastern states. 

Allegheny County Health Department (ACHD) revised the MANE-VU inventory in order to 

more accurately address local emissions impacting the Liberty-Clairton area.

Other local controls affecting the area that have not been used as part of the modeled 

demonstration of attainment have been included as “weight of evidence,” supporting the case 

that the area will achieve emission reductions. These controls include proposed deactivations or 

upgrades to stationary point sources, area/nonroad source emission rules, and mobile source 

emission reduction programs.

The modeling demonstration was performed using the Comprehensive Air quality Model with 

extensions (CAMx) model, with the Plume-in-Grid (PiG) option for selected local sources. Grid 

sizes ranged from 36 km for the continental U.S. to 0.8 km for southern Allegheny County and 

the Liberty-Clairton area. Years included in the inventory and modeling were 2007 for baseline 

case and 2014 for future projected case.

Procedures for modeling and attainment tests were followed according to EPA Modeling 

Guidance and the ACHD Liberty-Clairton PM2.5 Modeling Protocol. Attainment test 

methodology was used to combine final modeled results with actual monitored results over the 

2007-2014 timeframe. Total mass was reconstructed for PM2.5 species using the SANDWICH 

technique (sulfate, adjusted nitrate, derived water, inferred carbonaceous material balance 

approach).

Results from the attainment demonstration showed an overall reduction of sulfates, nitrates, and 

primary PM2.5 emissions throughout southwestern PA, including 291 tons of primary PM2.5 for

the Liberty-Clairton nonattainment area.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 3

Future projected design values for the Liberty and Clairton monitor sites are given below:

Projected Annual Design Value Ranges (Standard = 15.0 μg/m3)

Liberty 11.6-12.1 μg/m3

Clairton 8.9-9.1 μg/m3

Projected 24-Hour Design Value Ranges (Standard = 35 μg/m3)

Liberty 34-35 μg/m3

Clairton 18 μg/m3

A Reasonably Available Control Technology (RACT) and Reasonably Available Control 

Measures (RACM) analysis was made for the nonattainment area. No additional controls, or 

combination of additional controls, would advance the attainment date by one year, so RACT 

and RACM are satisfied for this SIP. 

This SIP also contains a contingency plan that provides assurance that, should the LibertyClairton area fail to attain the NAAQS by the attainment date, the area can be brought back into 

attainment as expeditiously as practicable.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 4

2 Problem Statement

2.1 Introduction

The Clean Air Act requires a State Implementation Plan (SIP) to be written for any area 

designated nonattainment for the annual PM2.5 pollution standard of 15.0 μg/m3 and/or for the 

daily PM2.5 pollution standard of 35 μg/m3. In 2009, the United States Environmental Protection 

Agency (EPA) designated the Liberty-Clairton area as a PM2.5 nonattainment area for the 2006 

standards. Liberty-Clairton is a 12.5 square mile subset of the surrounding Pittsburgh-Beaver 

Valley PM2.5 nonattainment area. The area was designated separately from the surrounding 

Pittsburgh-Beaver Valley area as a result of the complex interaction of a local emission source 

with meteorology and topography and subsequent air quality ranking factors that are not 

consistent with the surrounding area.

3

2.2 Location and Topography

The Liberty-Clairton nonattainment area, consisting of Glassport, Liberty, Lincoln, and Port Vue 

Boroughs and the City of Clairton, is located roughly 10 miles southeast of the City of 

Pittsburgh. The area is made up of complex river valley terrain, approximately 3 miles wide by 

5 miles long. It includes a 4-mile winding portion of the Monongahela River and is bordered by 

the Youghiogheny River to the east. The area includes rural land, densely populated residential 

areas, and industrial facilities. The 2010 population of the Liberty-Clairton area is 18,700, about 

1.5% of the population of the Allegheny County.

4

The river valleys lie at 718 feet in elevation above mean sea level (MSL), while adjacent hilltops 

can be greater than 1250 feet. Large temperature differences can be observed between the hilltop 

and valley floor (e.g. 2° - 7° F) during clear, light-wind, nighttime conditions. Strong nighttime 

drainage flows can cause differences of up to 180° in wind direction with 3-4 mph downward 

flows. Spikes in localized PM2.5 concentrations have coincided with temperature inversions.

The Liberty-Clairton area is home to several industrial sources of PM2.5 pollution. The U. S. 

Steel Mon Valley Works – Clairton Plant is the largest coke plant in the country, producing 

roughly 4.7 million net tons of coke annually. In addition the Liberty-Clairton area is also home 

to Koppers Industries, Inc.’s Clairton Tar Plant, nine permitted minor sources, and numerous 

small sources that do not require operating permits.

The Liberty-Clairton and Pittsburgh-Beaver Valley PM2.5 nonattainment areas are shown in 

Figure 2-1.

 

3 EPA factor analysis for Liberty-Clairton: 

http://www.epa.gov/pmdesignations/2006standards/rec/letters/03_PA_EPAMOD3.pdf

4 U.S. Census Bureau data: http://factfinder2.census.gov/faces/nav/jsf/pages/index.xhtml
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 5

Figure 2-1. Map of the Liberty-Clairton Area within the Pittsburgh-Beaver Valley Area
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 6

2.3 Meteorology

Temperature inversions contribute to elevated levels of PM2.5. (Note that, for the local region,

temperature inversions are measured at least twice daily by balloon-borne radiosondes sent into 

the atmosphere by the National Weather Service (NWS) forecasting office near the Pittsburgh 

International Airport (PIT) and are assumed to represent stability conditions all across the 

county.) A temperature inversion occurs when the air at the surface becomes cooler than the air 

above it, i.e., the rate of cooling of the air is greatest at ground level whereas the rate of cooling 

of the air is less at elevated levels. The cooler, heavier air then becomes trapped at the lower

elevation. As the major and minor sources of the area continue to emit PM2.5 pollution and the 

lower, cooler air becomes buoyantly stable, the PM2.5 is limited in its upward movement to 

disperse into the regional flow.

Typically, upon the inversion’s break, local PM2.5 is released into the upper atmospheric flow. 

Observations have shown that after this break, the Liberty monitor returns to a level comparable 

to or less than the concentrations measured at surrounding monitors. 

Appendix A contains documentation of meteorological conditions affecting Allegheny County in 

general and the Liberty-Clairton area in particular. First, a report titled Analysis of Meteorology 

on Days in 2005-2009 when PM2.5 was At Least 35.5 g/m3with a Focus on Extended, 

Continuous Exceedance Days provides an examination of weather conditions observed at the 

Pittsburgh NWS office on days in 2005 through 2009 when Federal Reference Method (FRM)

values in Allegheny County reached or exceeded a PM2.5 level of 35.5 μg/m3 (the level at which 

an exceedance of the new standard may be registered).

The investigation focused on time periods with extended (i.e., at least four), consecutive days

with PM2.5 of at least 35.5 μg/m3. During 2005 through 2009, nine such periods were identified. 

These extended periods occurred from May through November. The synoptic weather map 

features were rather complicated, but generally indicated the influence of a high pressure system 

in the northeast U.S. with airflow backing from NW to W or SW at the 500 mb level (about 3.4 

miles altitude). Typically, events associated with frontal activity, especially precipitation, 

appeared to dissipate the elevated PM2.5.

The maximum temperature for the month was usually reached during the extended PM2.5

periods. In fact, seven of the nine extended periods contained the monthly maximum 

temperature with the remaining two events reporting temperatures just one degree below the 

monthly high. Temperature departures averaged 7 °F above normal during the extended periods

and even more within two days after PM2.5 concentrations dropped below 35.5 μg/m3.

Resultant wind directions were around SW and speeds were light—typically 3 mph for resultant 

velocity and 4 mph for mean speed—during the high PM2.5 days. Wind directions were 

generally outside the S through W quarter and a bit faster for two days prior to the high days, 

while the directions tended to be within the S through W quadrant but still faster for two days 

after.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 7

Relative humidity averaged at the low 60 percent level. Levels prior to the elevated PM2.5 event 

averaged a little higher, while levels after averaged more than ten percentage points higher, 

which makes sense, since precipitation often occurred to help end the pollution event. Prior to 

the event little to no precipitation was measured; however, the reported substantial amounts 

associated with the end of the event apparently were sufficient to independently dampen the 

PM2.5 levels or at least to assist with the event’s abridgement.

Finally, atmospheric stability conditions, as indicated by the presence of a significant (i.e., at 

least 1 °C in strength) morning ground temperature inversion, were evaluated. During the 

extended PM2.5 events, morning inversions were generally moderate to strong, averaging 4.7 °C

in strength and topping out at a mean of 200 m. The frequency was relatively high at 83% of 

mornings. By comparison, such inversions averaged only 2.8 °C at a height of 150 m and a 

frequency of 61% before the event and 1.5 °C at 140 m and 56% after.

With regard to the 2007 baseline case year, Figure 2-2 displays a wind, pollution, and 

temperature rose derived from Liberty continuous monitoring data. As indicated on the graph, 

the most frequent and fastest winds were generally from the SW through W directions. 

Concentrations of PM2.5 as measured by Tapered-Element Oscillating Microbalance (TEOM) 

monitor equipment were largest from the S through SW directions. These are directions from 

which local and long-range transport carries substantial amounts of fine particulate matter to the 

Liberty monitoring site from large, stationary sources. And, logically, warmest temperatures 

were from the southerly directions. The coolest temperatures were from the W through NW 

directions.

The second document in Appendix A is an excerpt from The Processing of CALMET Files for 

Allegheny County’s PM2.5 SIP Analysis (Sullivan, 2007), which was a study conducted for a 

previous PM2.5 SIP. This report includes pertinent weather data such as an analysis of the 

potential for low-level convergence during stable nocturnal conditions in the Liberty-Clairton 

area.

The third item in Appendix A is an excerpt from a report completed earlier for ACHD titled 

Review of Meteorology at the Clairton Area: Strengthening Dispersion Modeling for State 

Implementation Plans (Sullivan, 1996). The report’s Executive Summary begins with the 

following:

“Air quality management in Allegheny County is complicated by valley influences on 

pollutant transport and dispersion. In particular, valley meteorology has made it more 

difficult to establish the connection between emission control strategies and projected air 

quality benefits. Without sound projections of air quality benefits, costly control 

decisions can miss the mark, requiring repetitive attainment demonstrations that are 

costly to industry and the County. This is an important issue in the County that affects 

PM10 and SO2 and potentially PM2.5 (as an issue of the future) in several key valley 

segments in Allegheny County.”
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 8

Figure 2-2. Wind Frequency and Speed, PM2.5 Concentration (TEOM Measurements), and 

Temperature Roses for the Liberty Monitoring Site, 2007

2.4 Monitored Data

PM2.5 monitors are currently located at 8 different monitoring locations throughout Allegheny 

County. The Lawrenceville monitor, located roughly 2 miles northeast of downtown Pittsburgh, 

is generally used to define urban concentrations of PM2.5 and can sometimes be used to represent 

regional concentrations. Two FRM PM2.5 monitors are located in the Liberty-Clairton area. The 

monitor at Liberty is located atop a school at high elevation near the center of the LibertyClairton area. The FRM monitor at Clairton is located atop a school at low elevation in the 

western portion of the area. Appendix B contains detailed monitored data and EPA Air Quality 

System (AQS) reports.

Allegheny County PM2.5 annual and 24-hour design values (3-year averages of annual and 24-

hour 98th-percentiles, respectively) for the timeframe 2000-2011 are shown in Figures 2-3 and 2-

4. All averages shown are for FRM monitors except Avalon, which was a Federal Equivalent 

Method (FEM) for 2010 and early 2011. The Liberty monitor shows concentrations that are 

higher than the rest of the Allegheny County network. (Note Figures 2-3 and 2-4 include some 

3-year periods with low recovery quarters – i.e., less than 75% valid data per quarter – as noted 

in Appendix B.)
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 9

Figure 2-3. PM2.5 FRM/FEM Annual Design Values, Allegheny County, 2000-2011

Figure 2-4. PM2.5 FRM/FEM 24-Hour Design Values, Allegheny County, 2000-2011
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 10

Figure 2-5 shows 24-hour PM2.5 concentrations at Liberty compared to the average of other 

Allegheny County sites on a 1-in-3 sampling schedule for year 2007 (the baseline case year for 

the modeling demonstration). Although the Liberty monitor shows concentrations similar to 

other sites at times, it also shows recurring peak days that are higher than the rest of Allegheny 

County. These high days lead to an excess of monitored PM2.5 at Liberty on both long-term and 

short-term bases.

Figure 2-5. 24-Hour PM2.5 Concentrations, 2007 Baseline Year, Liberty and Average of Other 

Allegheny County Sites

2.5 Speciation Data Analysis

Speciation data from the Chemical Speciation Network (CSN) and other networks are utilized to 

examine PM2.5 at the component level. The localized excess in the Liberty-Clairton area has 

been determined through speciation data analysis.

A significant portion of the ambient PM2.5 concentrations in the Pittsburgh Metropolitan 

Statistical Area (MSA) can be attributable to upwind sources in Ohio, West Virginia, and other 

states. Urban activity additionally contributes to concentrations within the Pittsburgh MSA, 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 11

compounded by localized activity in the Liberty-Clairton area. Liberty-Clairton is therefore 

impacted by a diverse combination of regional and local PM2.5 sources. Source apportionment 

results based on speciated data can be found in the report Allegheny County PM2.5 Source 

Apportionment Results using the Positive Matrix Factorization Model (PMF Version 3.0) and 

Conditional Probability Function (CPF) in Appendix C.

A comparison of regional, urban, and local concentrations shows species differences in the 

Liberty-Clairton area with respect to the surrounding area. Quaker City, OH and Dolly Sods, 

WV were examined as part of the rural/transport portion of PM2.5, while Lawrenceville, 

Florence, and Greensburg are part of the urban excess portion of PM2.5. Figure 2-6 shows longterm speciation averages, going west to east through the tri-state region, by major species over 

the weighted-data timeframe for this SIP.

Figure 2-6. Tri-State Major PM2.5 Species Concentrations

Concentrations at monitor sites roughly show increasing averages from west to east through the 

Pittsburgh MSA, followed by deceasing averages beyond the MSA. Liberty shows peaks for 

specific species, indicative of air composition that is not common throughout the greater tri-state 

region. (Note: “Other” component is the difference between total mass and the sum of the major 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 12

species. “Other” can represent particle-bound water, trace elements, unmeasured/unknown 

species, or differences due to analytical testing methods.)

Figure 2-7 below shows a pie chart of the long-term localized species excess at Liberty 

compared to the urban excess (i.e., Liberty minus the average of Lawrenceville, Florence, and 

Greensburg). These species are the focus of the modeling effort, since they are leading to the 

Liberty-specific concentrations compared to the surrounding area. (Note: EPA’s SANDWICH 

method modifies the species, including nitrates, organic carbon, and “other” component; see 

Section 6, Attainment Tests.) 

Figure 2-7. Localized Excess at Liberty, by Species Composition

An in-depth analysis of speciated PM2.5 components in Allegheny County can be found in the 

report PM2.5 Chemical Speciation Analysis for the Liberty-Clairton Area, 2005-2009 in 

Appendix C-1.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 13

3 Control Strategy

This section describes the control strategy implemented in order to reduce levels of PM2.5 in the 

Liberty-Clairton nonattainment area. These controls have been incorporated in the future case 

modeling for this SIP.

3.1 Interstate Transport Rules for EGUs

EPA issued the Clean Air Interstate Rule (CAIR)5in March 2005 to reduce the emissions of SO2

and NOx from applicable electric generating units (EGUs) located in a participating state (in the 

Eastern U.S.) that were determined to contribute significantly to ozone and PM2.5 nonattainment 

areas in a neighboring downwind state (per the CAA §110(a)(2)(D)). CAIR is a regional capand-trade program that established SO2 and NOx emission budgets for each participating state.

EPA issued the Cross-State Air Pollution Rule (CSAPR)6, originally known as the Transport 

Rule (TR), in July 2011 as a replacement interstate rule after CAIR was remanded without 

vacatur in Dec. 2008. CSAPR was subsequently vacated in Aug. 2012, with CAIR remaining in 

place for EGU emissions.

While ACHD continues to rely on CAIR as a federal interstate control program for EGUs, the 

CAIR inventory is an outdated inventory that may not adequately represent future conditions. 

There are inaccuracies in the CAIR projections as developed in 2005 regarding EGU controls and 

shutdowns. The CSAPR future case 2014 inventory was therefore used in the modeling 

demonstration as the more recent and realistic dataset for expected EGU emissions. Section 5.3.5 

provides more details of CAIR/CSAPR, recently reported, and expected emissions for EGUs.

The CSAPR 2014 inventory included in the modeling for this SIP was based on the inventory 

developed in July 2011. Supplemental revisions and adjustments made to CSAPR from Dec. 2011 

through June 2012 (not affecting PA allocations) were not included in the modeling inventories.

Figure 3-1 shows expected controls for coal-fired power plants in the Eastern U.S. by 2014.7 

Many of the controls involved power plants in the tri-state region of Pennsylvania, Ohio, and 

West Virginia (see Figure 3-2 for focus on this group of power plants, provided by EPA). 

Controls resulting from interstate EGU rules represent the majority of the regional reductions of 

PM2.5 precursors (SO2, NOx) needed to achieve attainment in the Liberty-Clairton area.

 

5 CAIR information is available at: http://www.epa.gov/cair/. CAIR SO2 budgets were promulgated upon 

issuance of the rule (see FR 70 (91) May 12, 2005, Table V-1), whereas the CAIR NOx budgets are 

promulgated in 40 CFR 96.140 (annual NOx) and 40 CFR 96.340 (ozone season NOx). CAIR Phase I 

became effective on 1/1/2009 for NOx and 1/1/2010 for SO2. CAIR Phase II, with corresponding 

reductions in the state budgets, becomes effective on 1/1/2015. For SO2, states have no discretion in their 

allowance allocation approach because CAIR uses the CAA Title IV SO2 allowances, which have already 

been allocated in perpetuity to individual units per Title IV of the CAA. In PA, NOx annual and ozone 

season allowances are allocated in accordance with 25 Pa. Code §§145.212 and 145.222, respectively.

6 CSAPR information is available at: http://www.epa.gov/airtransport/

7

Taken from EPA Clean Air Markets: http://epa.gov/airmarkets/quarterlytracking.html
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 14

Figure 3-1. Expected Coal-Fired Power Plants Controls for SO2 and NOx by 2014

Figure 3-2. Tri-State Expected Coal-Fired Power Plants Controls for SO2 and NOx by 2014
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 15

3.2 U. S. Steel Mon Valley Works

United States Steel Corporation’s (U. S. Steel) Mon Valley Works – Clairton Plant is the largest 

known individual source of PM2.5 in the Liberty-Clairton area. The Clairton Plant is located in 

the City of Clairton on the west bank of the Monongahela River, directly upwind of the Liberty 

monitor site. Controls at the Clairton Plant represent the majority of the PM2.5 reductions within 

the Liberty-Clairton area for future case year 2014.

A consent order and agreement between ACHD and United States Steel Corporation (U. S. Steel) 

was signed in March 2008, and amended in September 2010 and July 2011, requiring a number 

of actions at the U. S. Steel Mon Valley Works – Clairton Plant (and Edgar Thomson Plant) to 

resolve specific violations. Actions to be taken at the Clairton Plant included a number of 

installations and shutdowns, rebuilding of coke ovens, and other miscellaneous actions. The 

consent order and agreement is incorporated in the installation permit for the proposed Quench 

Towers 5A and 7A, constituting a federally enforceable agreement. The consent order as of July 

2011 has been included in Appendix F-2 as supplemental information. The actions used in the 

modeling demonstration are as follows:

 Batteries 7, 8, and 9: Batteries 7-9 were permanently shut down on April 16, 2009. The 

original date for shut down was December 31, 2012 in the consent order and agreement. 

It is expected that the proposed new C Battery will replace the production of Batteries 7-9 

at significantly lower emissions.

 Battery 19: U. S. Steel replaced 25 heating walls on Battery 19 by 2012. If necessary, an 

advanced patching plan will be implemented to reduce emissions.

 Quench Towers 5A and 7A: In September 2010, ACHD and U. S. Steel amended the 

March 2008 consent order and agreement to include the construction of new low 

emission quench towers for Batteries 13-15 and Batteries 19-20 by December 31, 2013. 

The new Quench Towers 5A and 7A will be used as the primary quench towers for 

Batteries 13-15 and Batteries 19-20, respectively. The current Quench Towers 5 and 7 

will serve as auxiliary quench towers.

Additional Clairton Plant repairs included in the modeling demonstration were due to a previous 

consent agreement in 2007:

 B Battery: In June 2007, ACHD and U. S. Steel entered into a consent order and 

agreement to rebuild the B Battery heating walls, completed in 2010.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 16

3.3 Source Shutdowns Adjacent to Liberty-Clairton

The following facilities immediately adjacent to the Liberty-Clairton area have been permanently 

retired, with no request for Emissions Reduction Credits (ERCs). Any future operation at these 

locations would require a new permit and new source review. These sources were therefore 

removed in the future case 2014 modeling inventory.

 General Motors (GM) Pittsburgh Facility: The GM stamping plant located in West 

Mifflin, west of Liberty-Clairton, was retired in April 2011.

 Ryan Metal Company, Inc.: The Ryan Metal scrap processing facility in McKeesport, 

east of Liberty-Clairton, was retired in 2009.

 Precoat Metals, a Division of Sequa Corporation: The Precoat metal surface coating 

facility in McKeesport, east of Liberty-Clairton, was retired in March 2009.

Tables of emissions by facility for Allegheny and Washington County sources, baseline and 

future cases, are given in Appendix F-2.

3.4 Regional Inventory Controls

Future case 2014 regional emissions inventories used for this attainment demonstration are as 

developed for Regional Planning Organizations (RPOs) such as the Mid-Atlantic/Northeast 

Visibility Union (MANE-VU) and the Lake Michigan Air Directors Consortium (LADCO). 

Control factors used to project regional emissions for these inventories incorporated federally 

enforceable rules and programs, including the following:

 Federal rules affecting specific sources/categories

 Federal MACT rules

 State-specific rules

Tables of the inventories used for the modeling demonstration by source category are given in 

Section 5. Technical Support Documents (TSDs) for the regional inventories and details of the 

specific controls are given in Appendices E and F. Projected emissions included the regional 

inventories that are not federally enforceable were used for modeling purposes only.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 17

4 Emissions Inventory

Section 51.1008 of 40 CFR Part 51 requires an emissions inventory, based on the requirements 

of section 172(c)(3) of the CAA, for any PM2.5 nonattainment area. As specified by the EPA, 

pollutants inventoried for the Liberty-Clairton PM2.5 nonattainment area include PM10 and PM2.5

along with precursors SO2, NOx, VOC, and NH3. Much of the particulate emissions within the 

nonattainment area are transported from the surrounding area, including Southwestern

Pennsylvania and states to the west and south of Pennsylvania.

The emissions inventory for Liberty-Clairton 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/nonroad 

sources, and mobile sources. The stationary point sources include two major sources (U. S. Steel 

Clairton and Koppers), two “synthetic minor” sources (Pennsylvania Electric Coil and 

Durabond), and seven minor sources.

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

Northeast Visibility Union (MANE-VU) for the Northeastern U.S. for use in regional analyses 

and SIPs. The Liberty-Clairton emissions inventory was developed from the regional MANEVU inventories with revisions by TranSystems|E.H. Pechan (TS|Pechan) for area, nonroad, and 

mobile sources and by ACHD for stationary point sources. (More information on the TS|Pechan 

contract can be found in Section 5.) 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.

The year 2007 was used for baseline emissions inventory, and year 2014 was used for the 

projected inventory. Local controls were focused on direct PM2.5 emissions from stationary 

point emissions, while regional controls for SO2 and NOx were based on CSAPR allocations.

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

inventory listings are included in Appendix D, and information on the development of the 

baseline and projected emissions and modeling inventories are given in Appendices E and F.

 Stationary point sources are sources for which ACHD collects individual emissionsrelated information. Revisions were made by ACHD to 2007 point source emissions 

based on newer emissions estimates that do not reflect originally submitted data. 

Additionally, the future case includes revisions by TS|Pechan that were not part of the 

MANE-VU projections.

 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. 

Area emissions for the Liberty-Clairton area were estimated by TS|Pechan.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 18

 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. Nonroad emissions for the LibertyClairton area were estimated by TS|Pechan.

 Mobile sources include passenger cars and light-duty trucks, other 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 estimated 

by TS|Pechan.

Emissions inventory summaries for baseline and future projected cases are shown in Tables 4-1

and 4-2 below. These emissions represent sources only within the 5-municipality LibertyClairton area and not the surrounding area.

Table 4-1. Baseline 2007 Emissions (Tons/Year)

Liberty-Clairton Area 

(2007) PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 946.6 1136.9 1741.3 4841.9 590.5 18.4

Area Sources 26.3 50.5 50.1 38.8 255.9 4.2

Nonroad Sources 15.0 15.9 17.2 437.9 86.6 0.2

Mobile Sources 9.9 10.4 2.1 274.3 172.5 4.7

Totals 997.8 1213.8 1810.9 5592.9 1105.6 27.5

Table 4-2. Future Projected 2014 Emissions (Tons/Year)

Liberty-Clairton Area 

(2014) PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 662.7 853.7 1720.5 4349.3 460.1 17.6

Area Sources 25.6 49.5 49.6 38.5 252.0 4.2

Nonroad Sources 12.4 12.7 6.0 387.1 58.5 0.2

Mobile Sources 6.2 6.6 0.9 151.0 95.1 3.4

Totals 706.8 922.4 1777.1 4925.9 865.6 25.3
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 19

5 Modeling

5.1 Design and Modeling Protocol

Modeling for the Liberty-Clairton area was focused on the simulation of regional impacts due to 

PM2.5 precursors and the localized impacts from direct PM2.5 sources. A photochemical model 

with plume-tracking options was utilized at fine grid resolution to adequately model both longrange transport and near-field impacts.

ACHD followed modeling procedures outlined by the PM2.5 Modeling Protocol, 2006 PM2.5

Standards, Liberty-Clairton Nonattainment Area (given in Appendix G-1) and by the EPA 

Modeling Guidance8. Modeling was performed using the CAMx model with the Plume-in-Grid 

(PiG) and Particle Source Apportionment Technology (PSAT) modules for local source tracking.

5.2 Emissions/Modeling Assistance

To better understand air-quality impacts from PM2.5 emissions in Allegheny County, especially 

in the Liberty-Clairton area, and to continue with effective programs to attain and maintain the

NAAQS, ACHD contracted three highly qualified consulting firms. The following three 

contractors assisted the ACHD with three different but interrelated PM2.5 SIP projects. 

 TranSystems|E.H. Pechan & Associates (TS|Pechan) of Springfield, VA conducted an indepth investigation of transportation and area-wide sources of PM2.5 in southern 

Allegheny County (ACHD contract title Consultant Technical Support for Air Pollutant 

Area and Mobile Sources Analyses)

 Alpine Geophysics of Arvada, CO operated a state-of-the-science meteorological model 

(ACHD contract title Meteorological Data Preparation)

 ENVIRON International Corporation (ENVIRON) of Novato, CA provided advanced 

computer modeling that incorporated the work of the other two contractors into a morerealistic representation of PM2.5 impacts in Allegheny County (ACHD contract title 

Reactive Pollutant Modeling)

Each company had been tasked with a critical component of the “air-pollution system.” This 

system consists of sources, dispersion, and receptors of pollutants. Furthermore, air-pollutant 

modeling, which was a critical part of the contracting work, ties the system components together 

to produce an expected impact of known pollution sources on surrounding communities.

Modeling is a mainstay of today’s environmental field; it is a tool used to simulate real-world 

conditions. For air-quality studies, “air-dispersion modeling,” as described by the EPA, “uses 

mathematical formulations to characterize the atmospheric processes that disperse a pollutant 

 

8 Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals 

for Ozone, PM2.5, and Regional Haze, U.S. EPA, April 2007.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 20

emitted by a source. Based on emissions and meteorological inputs, a dispersion model can be 

used to predict concentrations at selected downwind receptor locations.”

Following are brief descriptions of the contract work that helped to produce the demonstration of 

Allegheny County’s (including Liberty-Clairton area) attainment and continued maintenance of 

the new 24-hour PM2.5 standard.

Consultant Technical Support for Air Pollutant Area and Mobile Sources Analyses contract. A 

more reliable representation of observed (and forecasted) air-quality concentrations can be 

achieved by collecting more and better information. Such collection is part of the ACHD’s 

continued monitoring efforts throughout the county. However, additional investigation of PM2.5

sources had been assigned to contractor TS|Pechan. Specifically, TS|Pechan reviewed existing 

PM2.5 inventories and related documents for local area and mobile sources. The review included 

field work, records and data searches, and calculations necessary to evaluate and modify the 

existing 2007 SIP emissions inventories. Furthermore, TS|Pechan performed a reasonably 

available control measures (RACM) analysis, which included examining reasonably available 

control technology (RACT), on all area and mobile sources listed in the revised 2007 SIP 

emissions inventory. This work addressed the “source” component of the air-pollution system 

described above.

Meteorological Data Preparation contract. The “dispersion” aspect of the air-pollution system 

was assumed by the ACHD’s analysis of ongoing county and federal meteorological station data 

along with the addition of Alpine Geophysics work. Under this contract, Alpine Geophysics 

expedited weather data processing for use with air-quality models such as, but not limited to 

AERMOD (American Meteorological Society/Environmental Protection Agency Regulatory 

Model), CALPUFF (originally sponsored by California Air Resources Board), and CAMx 

(“Comprehensive Air quality Model with extensions”). The data processing was performed 

using the WRF model (a model originally developed with assistance from the National Center 

for Atmospheric Research, the National Oceanic and Atmospheric Administration, and other 

government and university organizations). Large- and fine- mesh grids at numerous vertical 

levels were employed to simulate atmospheric conditions across Allegheny County, with a focus 

on the Liberty-Clairton area. In addition, the Plume-in-Grid (PiG) model was used to simulate 

fine particulate matter impacts within the Liberty-Clairton area. (Note that ENVIRON was a 

subcontractor to Alpine Geophysics on the data preparation work.)

Reactive Pollutant Modeling contract. Finally, to address the “receptors” of the air-pollution 

system, ENVIRON was contracted to assist the ACHD with determining present and future 

PM2.5 concentrations in the county. ENVIRON’s work involved application of CAMx - a model 

developed by ENVIRON. Using county tabulated emissions, and mobile and area emission 

values calculated from the Sparse Matrix Operator Kernel Emissions System (SMOKE) model, 

along with WRF model results as input to CAMx, ENVIRON conducted air modeling using 

large and fine grids (see below). Then, after validating the model, ENVIRON ran CAMx for 

present conditions and control strategies to demonstrate compliance with the PM2.5 NAAQS. 

(Note that Alpine Geophysics was a subcontractor to ENVIRON on the modeling project.)
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 21

5.3 Methodology

The modeling methodology focused on the transformation of PM2.5 precursors along with the 

near-field impact of primary PM2.5. The EPA Modeling Guidance outlines techniques that can 

be used to model primary PM2.5. This section describes the steps used to model the LibertyClairton area. More information on the model methodology can be found in Appendix G

(Modeling Documentation).

5.3.1 Models Selection

The Comprehensive Air Quality Model with extensions (CAMx Version 5.4, released in October 

2011) was used by ENVIRON for the modeling of the Liberty-Clairton area. The model was 

designed to include both regional and localized PM2.5 impacts formed by both primary and 

secondary mechanisms. CAMx includes several features that were deemed important for PM2.5

modeling of the Liberty-Clairton area:

 Two-way grid nesting to allow regional- and local-scale impacts within the same simulation

 Subgrid-scale PiG module to sample the puffs for the contributions of local sources

 CB6 chemical mechanism that represents the latest understanding of photochemistry

 PSAT, important for obtaining the separate contributions from local sources

Since the Liberty-Clairton excess is composed of both primary and secondary components of 

PM2.5, emission inputs for CAMx included all PM2.5 precursor pollutants (SO2, NOx, VOCs, 

NH3) along with primary filterable and condensable PM2.5.

Meteorological inputs for CAMx were generated by Alpine Geophysics using the WRF model. 

The WRF grids followed the same grid resolutions as the CAMx, creating several layers of 

meteorological data for each modeled grid cell.

5.3.2 Local Source Treatment

To account for significant individual emission sources in an area of interest, the Plume-in-Grid 

(PiG) option incorporates a puff/plume model within the larger-scale grid model CAMx. 

According to Karamchandani, et al., 2011, “[t]he embedded model tracks the sub-grid scale 

process (e.g., elevated point source emissions) until the fine scale variability becomes 

unimportant (referred to as the ‘puff dumping’ or ‘hand-over’ point), at which point the grid 

model takes over the calculations for that process while the embedded model continues tracking 

sub-grid scale processes.” The authors go on to say that a plume “is represented by a myriad of 

three-dimensional puffs that are advected and dispersed according to the local 

micrometeorological characteristics.... Also, the effects of buoyancy on plume rise and initial 

dispersion are simulated by solving the conservation equations for mass, heat, and momentum.” 

Furthermore, “[c]hemical species concentrations in the puffs are treated as perturbations from the 

background concentrations.”
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 22

Additionally, the Particle Source Apportionment Technology (PSAT) option was used to track 

contributions from a selected group of local sources. This technique enabled the results of both 

regional and local impacts to be used in the attainment tests (see Section 6).

The local point sources selected for PiG and PSAT handling were based on location within or in 

close proximity to the Liberty-Clairton area, amount of baseline year 2007 pollutant emissions, 

and source factor “fingerprint” based on the PMF source apportionment. That is, these sources 

are the sources that are most likely leading to concentrations that are measured at the Liberty 

monitor site. Sources selected for local source treatment are given in Table 5-1 below, along 

with their associated precursor and PM2.5 emissions in tons/year.

Table 5-1. Local Sources for PiG and PSAT Treatment

Facility

Precursors 

(tpy of SO2,

NOx,VOC,NH3)

PM2.5

(tpy)

Dist. From

Liberty (km) Comments

AKJ Industries 0.03 0.03 2.0 Liberty-Clairton area

Braddock Recovery 6.62 1.70 7.7 Located at US Steel ET Plant

Clairton Slag 12.87 2.75 6.6 Upwind

Consol Coal 0.87 0.66 6.3 Upwind

CP Industries 2.09 0.94 1.7 Proximity to area

Dura-Bond Industries 14.13 3.60 1.8 Liberty-Clairton area

Eastman Chemical Resins 25.50 17.57 7.0 Upwind, major source

ELG Metals 0.48 1.93 1.5 Liberty-Clairton area

Gardner Denver Nash 4.09 0.19 5.1 Upwind

GM Metal Stamping 9.24 1.28 3.6 Proximity to area

Guardian Industries 782.94 19.97 8.5 Upwind, major source

Kelly Run Sanitation 19.15 4.98 8.5 Upwind

Kinder-Morgan 4.64 0.20 3.5 Proximity to area

Koppers Tar Plant 29.13 5.96 2.3 Liberty-Clairton area

Liberty Pultrusions 11.74 0.05 3.1 Proximity to area

Marathon Ashland 6.94 0.37 8.4 Upwind

Mid-Continent C & C 6.55 1.79 2.8 Liberty-Clairton area

Mon Valley Transport 0.00 3.76 1.7 Liberty-Clairton area

Pennsylvania Electric Coil 2.38 0.03 2.3 Liberty-Clairton area

Precoat Metals 27.78 0.76 2.3 Proximity to area

Ryan Metals 0.42 7.10 2.3 Proximity to area

Sanyo 8.60 1.73 7.0 Upwind, located at Eastman

Tube City IMS Braddock 0.00 3.07 7.7 Located at US Steel ET Plant

Tube City IMS Clairton 0.00 0.31 2.8 Liberty-Clairton area

TYK Refractories 12.60 0.48 5.9 Upwind

US Steel – Clairton Plant 7136.30 929.18 2.1 Liberty-Clairton area

US Steel – ET Plant 2255.84 803.29 7.8 Major source

US Steel – Irvin Plant 1223.10 51.12 2.9 Major source

Allegheny Energy Mitchell 2145.24 79.85 14.3 EGU

GenOn Energy Elrama 10324.22 512.82 8.9 EGU
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 23

The local sources are additionally shown on an aerial map in Figure 5-1 below.

Figure 5-1. Aerial Map of Local Sources for PiG and PSAT Handling
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 24

5.3.3 Modeling Domains

WRF and CAMx were run for a 36/12/4/0.8 km domain structure, defined as follows:

 36 km continental U.S. (CONUS) domain to be the standard RPO domain, run as a standalone simulation, results post-processed to define Boundary Conditions (BCs) for the 12 

km North East U.S. (NEUS) domain

 12 km NEUS domain that includes states in the Midwestern and Northeastern U.S. that 

the Cross State Air Pollution Rule (CSAPR) identified as contributing significantly to 

PM2.5 at Liberty

 A 4 km domain that covers southwestern Pennsylvania (SWPA) and adjacent areas in 

West Virginia and Ohio

 A nested grid of 0.8 km (800 m) for the area within and surrounding the Liberty-Clairton 

area

Figures 5-2 through 5-4 show maps of the modeled domains.

Figure 5-2. 36/12/4/0.8 km Modeling Domains

-2520 -2160 -1800 -1440 -1080 -720 -360 0 360 720 1080 1440 1800 2160 2520

-1800

-1440

-1080

-720

-360

0

360

720

1080

1440

1800

ACHD Proposed CAMx Domain

36 km 148 x 112 (-2736, -2088) to (2592, 1944)

12 km 174 x 117 ( 72, -540) to (2160, 864)

04 km 54 x 60 ( 1296, 48) to (1512, 288)

0.8 km 75 x 60 ( 1392, 144) to (1452, 192)

12 km

04 km

0.8 km

36 km
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 25

Figure 5-3. 12/4/0.8 km Modeling Domains

Figure 5-4. Initial 4/0.8 km Modeling Domains

(Note: The final 0.8 km domain was reduced in size.)

120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 1680 1800 1920 2040 2160

-480

-360

-240

-120

0

120

240

360

480

600

720

840

ACHD Proposed CAMx Domain

36 km 148 x 112 (-2736, -2088) to (2592, 1944)

12 km 174 x 117 ( 72, -540) to (2160, 864)

04 km 54 x 60 ( 1296, 48) to (1512, 288)

0.8 km 75 x 60 ( 1392, 144) to (1452, 192)

12 km

04 km

0.8 km

1320 1360 1400 1440 1480

80

120

160

200

240

280

ACHD Proposed CAMx Domain

36 km 148 x 112 (-2736, -2088) to (2592, 1944)

12 km 174 x 117 ( 72, -540) to (2160, 864)

04 km 54 x 60 ( 1296, 48) to (1512, 288)

0.8 km 75 x 60 ( 1392, 144) to (1452, 192)

04 km

0.8 km
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 26

5.3.4 Modeled Inventories

Emissions inventories for the baseline year modeling were based on MANE-VU/MARAMA9

LADCO10, and the Southeastern Modeling, Analysis, and Planning (SEMAP11) Project 2007 

inventories. In cases where the 2007 data was unavailable, U.S. EPA’s 2008 National Emissions 

Inventory (NEI12) was back-casted to 2007. Revisions were made by ACHD and TS|Pechan to 

Allegheny County sources, based on updated stack test data, corrections to emissions or stack 

parameters, or revised emission calculation methodologies. Details of the inventory 

development are given in Appendices E and F. Table 5-2 below shows the 2007 modeled 

inventories by U.S. region.

Table 5-2. 2007 Baseline Case Inventories by Region

Source 

Category

LibertyClairton 

Area 

Allegheny 

County/SWPA 

MANE-VU

States

SEMAP/

SESARM 

States

LADCO

States

Other 

States

Area TS|Pechan 

2007

MANE-VU 

2007v3 Final 

(corrected)

MANE-VU 

2007v3 Final

EPA 2008 

NEIv1.5

EPA 2008 

NEIv1.5

EPA 2008 

NEIv1.5

NonRoad TS|Pechan 

2007 

MANE-VU 

2007v3 Final 

(corrected) 

MANE-VU 

2007v3 Final

SEMAP 2007 

Draft

EPA 2008 

NEIv1.5

EPA 2008 

NEIv1.5

OnRoad 

Mobile

LADCO 

2007BaseCv8

LADCO 

2007BaseCv8

LADCO 

2007BaseCv8

LADCO 

2007BaseCv8

LADCO 

2007BaseCv

8

LADCO 

2007BaseCv

8

NonEGU 

Point

ACHD 2007 

(corrected)

ACHD 2007 

(corrected)/ 

MANE-VU 

2007v3 Final 

MANE-VU 

2007v3 Final

SEMAP 2007 

Draft

EPA 2008 

NEIv1.5

EPA 2008 

NEIv1.5

EGU 

Point ---

MANE-VU 

2007v3 Final

MANE-VU 

2007v3 Final

SEMAP 2007 

Draft

2007 dayspecific 

hourly CEM 

2007 dayspecific 

hourly CEM 

Fires

2007 

BlueSky Fire 

Emissions 

EPA, 2010 

2007 BlueSky 

Fire Emissions 

EPA, 2010 

2007 

BlueSky Fire 

Emissions 

EPA, 2010 

SEMAP 2007 

Draft

2007 

BlueSky Fire 

Emissions 

EPA, 2010 

2007 

BlueSky Fire 

Emissions 

EPA, 2010 

Biogenics 

Day Specific 

SMOKEBEIS

Day Specific 

SMOKE-BEIS

Day Specific 

SMOKEBEIS

Day Specific 

SMOKE-BEIS

Day Specific 

SMOKEBEIS

Day Specific 

SMOKEBEIS

 

9

http://www.marama.org/

10 http://www.ladco.org/

11 http://www.metro4-sesarm.org/SEMAPAbout.asp

12 http://www.epa.gov/ttn/chief/net/2008inventory.html
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 27

Emissions inventories for the future year modeling were based on MANE-VU inventories

interpolated to 2014, LADCO 2014 projections applied to NEI 2008 data, and CSAPR 2014 

inventories.13 Similar to the baseline case, revisions were made by ACHD and TS|Pechan to 

Allegheny County sources for 2014. Table 5-3 below shows the 2014 modeled inventories by 

U.S. region.

Table 5-3. 2014 Future Case Inventories by Region

Source 

Category

LibertyClairton 

Area 

Allegheny 

County/SWPA 

MANE-VU

States

SEMAP/

SESARM 

States 

LADCO

States

Other 

States

Area TS|Pechan 

2014

MANE-VU

2017v3 Final 

(corrected, 

interpolated to 

2014)

MANE-VU 

2017v3 Final 

(interpolated to 

2014)

CSAPR 2014 

cs_05b 

CSAPR 

2014 cs_05b 

CSAPR 

2014 cs_05b 

NonRoad TS|Pechan 

2014 

MANE-VU 

2017v3 Final 

(corrected, 

interpolated to 

2014) 

MANE-VU 

2017v3 Final 

(interpolated to 

2014)

CSAPR 2014 

cs_05b 

CSAPR 

2014 cs_05b 

CSAPR 

2014 cs_05b 

OnRoad 

Mobile

CSAPR 

2014 

cs_05b

CSAPR 2014 

cs_05b 

CSAPR 2014 

cs_05b

CSAPR 2014 

cs_05b 

CSAPR 

2014 cs_05b 

CSAPR 

2014 cs_05b 

NonEGU 

Point

ACHD 

2014 

(corrected)

ACHD 2014 

(corrected)/ 

MANE-VU 

2017v3 Final 

(interpolated to 

2014) 

MANE-VU 

2017v3 Final 

(interpolated to 

2014)

CSAPR 2014 

cs_05b

EPA 2008 

NEIv1.5, 

w/LADCO 

2014 factors

CSAPR 

2014 cs_05b

EGU 

Point ---

CSAPR 2014 

TR1_remedy

CSAPR 2014 

TR1_remedy 

CSAPR 2014 

TR1_remedy

CSAPR 

2014 

TR1_remedy

CSAPR 

2014 

TR1_remedy

Fires

2007 

BlueSky 

Fire 

Emissions 

EPA, 2010 

2007 BlueSky 

Fire Emissions 

EPA, 2010 

2007 BlueSky 

Fire Emissions 

EPA, 2010 

SEMAP 

2007 Draft

2007 

BlueSky 

Fire 

Emissions 

EPA, 2010 

2007 

BlueSky 

Fire 

Emissions 

EPA, 2010 

Biogenics 

Day 

Specific 

SMOKEBEIS

Day Specific 

SMOKE-BEIS

Day Specific 

SMOKE-BEIS

Day Specific 

SMOKEBEIS

Day Specific 

SMOKEBEIS

Day Specific 

SMOKEBEIS

 

13 http://www.epa.gov/ttn/chief/emch/index.html#final
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 28

Baseline-to-future case modeled emissions reductions for point, area, and nonroad source 

categories (including Marcellus Shale area source emission estimates for Fayette, Greene, 

Washington, and Westmoreland counties, see Appendix F-2 for details) in Southwestern PA

(SWPA) are shown below in Table 5-4. Reductions are shown by county or source group –

counties do not include electric generating units (EGUs), which are listed as a separate source 

group for SWPA. Note: Allegheny County excludes Liberty-Clairton area emissions.

Table 5-4. SWPA Modeled Emissions Reductions, Point/Area/Nonroad, 2007 to 2014

County/Group SO2 NOx VOC NH3 PM10 PM2.5

Allegheny -551 -2612 -2319 3 -250 -309

Liberty-Clairton Area -33 -544 -163 -1 -287 -287

Armstrong -44 -110 -295 3 -14 -20

Beaver -134 -837 -451 36 -63 -57

Butler -169 -658 -400 8 -37 -45

Fayette -104 985 1146 3 -46 -6

Greene -28 3013 4610 3 -16 58

Indiana -75 -182 -264 5 -9 -22

Lawrence -68 -1735 -268 7 -47 -37

Washington -166 3479 7420 8 -19 65

Westmoreland -446 822 784 5 -82 -41

EGUs -499871 -46592 580 380 -200 1972

EGUs showed the largest reductions for SO2 and NOx, while Allegheny County and the LibertyClairton area showed the largest reductions for PM2.5. Increases in NOx and VOC emissions for 

Fayette, Greene, Washington, and Westmoreland Counties are due to projected increases in shale 

gas exploration and production.

5.3.5 Projected EGU Inventories

As mentioned in Section 3.1, CSAPR was used for the modeling of projected EGU emissions for 

2014. The CAIR inventory was developed in 2005 on a 2001-based air quality modeling 

platform, while CSAPR was developed in 2011 using a 2005-based platform. The CSAPR 

future case inventory was used in the modeling as the more recent and realistic dataset for 

expected EGU emissions.

The CAIR and CSAPR future case remedy inventories (2015 and 2014, respectively) focused on 

the control of PM2.5 precursor emissions of SO2 and NOx for the Eastern U.S. but also included 

emissions for the rest of the country. For a look at the validity of the CAIR and CSAPR 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 29

inventories in relation to recent reported data, future case emissions for CAIR14 and CSAPR15

were compared to 2012 reported values from EPA’s Clean Air Markets Division (CAMD).

16

Emissions shown in Table 5-5 below represent totals from CAIR and CSAPR future cases along 

with CAMD 2012 reported emissions for the following source categories: cogeneration, electric 

utility, and small power producer. Projected and reported SO2 and NOx emissions totals are 

shown by region: contiguous U.S. (excluding AK, HI, and DC), CSAPR-controlled states (28 

eastern states), and PA and surrounding states (PA, OH, WV, and MD).

Table 5-5. CAIR 2015, CSAPR 2014, and CAMD 2012 SO2 and NOx Emissions

Region SO2 CAIR 2015 

(tons)

SO2 CSAPR 2014 

(tons)

SO2 CAMD 2012 

(tons)

Contiguous U.S. 5,223,044 3,356,577 3,316,811

CSAPR-Controlled 

States 4,618,909 2,919,042 3,036,681

PA and Surrounding 

States 531,325 419,233 687,176

Region NOx CAIR 2015 

(tons)

NOx CSAPR 2014 

(tons)

NOx CAMD 2012 

(tons)

Contiguous U.S. 2,199,729 1,890,578 1,706,442

CSAPR-Controlled 

States 1,561,493 1,428,480 1,354,453

PA and Surrounding 

States 222,766 279,901 278,436

CAMD data shows that reported emissions of SO2 and NOx have decreased significantly in the 

U.S. in recent years. Reported 2012 emissions for the contiguous U.S. and CSAPR states are 

already well below CAIR 2015 levels and are near or below CSAPR 2014 emissions. Only PA 

and surrounding states are significantly higher than projected CAIR or CSAPR values.

Long-term (10-year) trends for reported CAMD emissions and heat inputs were examined for the 

Eastern U.S. to determine if emissions are steadily decreasing without a loss in electricity 

demand. Figures 5-5 through 5-7 show trends for SO2, NOx, and heat inputs for CSAPRcontrolled states over the timeframe 2003-2012.

 

14 2015 Final CAIR Modeling: http://www.epa.gov/airmarkets/progsregs/epa-ipm/cair/index.html

15 2014 CSAPR TR1 Remedy: ftp://ftp.epa.gov/EmisInventory/2005v4_2/2014emis

16 CAMD database: http://ampd.epa.gov/ampd/ (accessed 2/13/2013)
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 30

Figure 5-5. Reported CAMD SO2 Emissions (tons), CSAPR States, 2003-2012

Figure 5-6. Reported CAMD NOx Emissions (tons), CSAPR States, 2003-2012
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 31

Figure 5-7. Reported CAMD Heat Inputs (MMBtu), CSAPR States, 2003-2012

The trends in Figures 5-5 through 5-7 indicate that SO2 and NOx are steadily decreasing in the 

Eastern U.S. over the 10-year timeframe with little change in heat input levels; therefore, 

decreases are not due solely to low electricity generation. It may be reasonable to assume that 

the emission reductions will continue to occur in the 2013-2014 timeframe.

Furthermore, deactivations of many EGUs occurred in 2012 or have been proposed for 2013 

through mid-2015 due to compliance with the Mercury Air Toxics Standards and/or other 

factors. To examine the potential reductions due to the announced deactivations for PA and 

surrounding states, CAMD 2012 emission levels were revised to reflect the deactivations for 

2012 through mid-2015, as tracked by PJM Interconnection.

17

 (Deactivations occurring in 2012 

were included to remove partial-year 2012 CAMD emissions).

Also, SO2 emissions from the Homer City plant in Indiana County, PA were revised to reflect the 

planned installation of control equipment by Oct. 2014.18

 

17 PJM Interconnection: http://www.pjm.com/~/media/planning/gen-retire/pending-deactivationrequests.ashx (pending as of Mar. 11, 2013)

18 Homer City Plan Approval: 

http://files.dep.state.pa.us/RegionalResources/SWRO/SWROPortalFiles/AQ_HomerCity/Issued%20Plan

%20Approval%20PA-32-00055H%204-2-12.pdf
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 32

Table 5-6 shows projected and reported SO2 and NOx emissions totals for U.S. regions, similar to 

the Table 5-5, but with CAMD 2012 emissions revised to include expected reductions due to 

proposed deactivations and planned controls.

Table 5-6. CAIR 2015, CSAPR 2014, and CAMD 2012 SO2 and NOx Emissions adjusted 

for PA and Surrounding State Expected Reductions 2013 to mid-2015

Region SO2 CAIR 2015 

(tons)

SO2 CSAPR 

2014 (tons)

SO2 CAMD 2012

with PA/Surrounding 

Expected Reductions by

mid-2015 (tons)

Contiguous U.S. 5,223,044 3,356,577 2,901,220

CSAPR-Controlled 

States 4,618,909 2,919,042 2,621,090

PA and Surrounding 

States 531,325 419,233 322,020

Region NOx CAIR 

2015 (tons)

NOx CSAPR 

2014 (tons)

NOx CAMD 2012

with PA/Surrounding 

Expected Reductions by

mid-2015 (tons)

Contiguous U.S. 2,199,729 1,890,578 1,656,886

CSAPR-Controlled 

States 1,561,493 1,428,480 1,304,897

PA and Surrounding 

States 222,766 279,901 241,772

The revised CAMD emissions with known expected reductions for PA and surrounding states 

would lower the current reported levels of SO2 and NOx to below CSAPR levels for all regions. 

Note that CAIR NOx is lower than both CSAPR and reported levels for PA and surrounding 

states, suggesting that the CAIR NOx projections may have been inaccurate.

Additionally, many EGUs that were projected to install emission controls are switching to 

natural gas. These fuel switches have not been accounted for in the CSAPR inventory as 

developed in 2011, resulting in a potentially conservative modeling approach for the future case.

Considering the comparisons to both CAIR and reported data, the CSAPR 2014 remedy case is 

an adequate inventory of expected EGU emissions for modeling purposes. Emissions totals are 

given by state (and by facility for PA and surrounding state CAMD data) in Appendix E-6.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 33

5.4 Modeled Impacts

CAMx modeled impacts for the 0.8 km grid in and around the Liberty-Clairton area were 

combined on an hourly basis with locally-tracked 100 m “nearby” receptor concentrations at the 

Liberty and Clairton sites. These 100 m receptors were defined as receptors surrounding the 

FRM site at similar elevation that would measure similar concentrations to the actual monitor 

FRM location.

Figure 5-8 shows the “nearby” receptors that were used for Liberty (40 receptors) and Clairton 

(51 receptors).

Figure 5-8. Liberty and Clairton Nearby Receptors

Additional details on the nearby receptors are given in the Modeling Protocol in Appendix G-1.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 34

Modeled CAMx quarterly average and high day (top 10%) average impacts for the Liberty 

receptors, by regional and local impacts, are given in Tables 5-7 and 5-8. The local and regional 

impacts were tracked separately by the CAMx model using the Particulate Source 

Apportionment Technology tool. The modeled impacts from point sources identified for local 

treatment are summed as the local portion of the CAMx impacts.

All values in Tables 5-7 and 5-8 are in μg/m3, with the species defined as follows:

SO4 = sulfate ion POA = primary organic aerosol

NO3 = nitrate ion SOA = secondary organic aerosol

NH4 = ammonium ion EC = elemental carbon

OTHER = unspeciated PM2.5

Table 5-7. Liberty Quarterly Modeled Averages (μg/m3)

Local Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 0.310 0.016 0.090 0.169 0.000 0.202 1.557 2.344

2Q 0.407 0.008 0.118 0.221 0.000 0.274 2.018 3.046

3Q 0.612 0.002 0.184 0.282 0.000 0.373 3.134 4.587

4Q 0.439 0.013 0.154 0.203 0.000 0.280 2.386 3.475

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 0.254 0.020 0.079 0.159 0.000 0.190 1.215 1.917

2Q 0.347 0.014 0.091 0.209 0.000 0.264 1.632 2.557

3Q 0.491 0.004 0.141 0.261 0.000 0.358 2.464 3.719

4Q 0.352 0.019 0.124 0.186 0.000 0.264 1.845 2.790

Regional Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 2.475 2.040 1.348 3.478 0.053 1.386 4.190 14.970

2Q 4.791 0.402 1.244 1.008 0.022 0.823 1.714 10.004

3Q 7.259 0.051 1.369 0.997 0.029 1.026 2.293 13.024

4Q 3.542 1.632 1.421 3.664 0.039 1.531 4.560 16.389

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 1.668 1.818 1.062 2.773 0.044 0.606 3.677 11.648

2Q 2.251 0.378 0.880 0.707 0.017 0.318 1.454 6.005

3Q 3.047 0.065 0.986 0.659 0.023 0.405 1.966 7.151

4Q 2.057 1.242 1.008 2.968 0.034 0.665 3.921 11.895
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 35

Table 5-8. Liberty Quarterly High Day Modeled Averages (μg/m3)

Local Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 0.788 0.058 0.211 0.424 0.000 0.507 3.748 5.736

2Q 1.036 0.024 0.383 0.383 0.000 0.589 5.679 8.094

3Q 1.145 0.001 0.429 0.366 0.000 0.587 6.005 8.533

4Q 0.880 0.076 0.206 0.395 0.000 0.433 4.222 6.212

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 0.615 0.082 0.189 0.387 0.000 0.464 2.664 4.401

2Q 0.835 0.054 0.301 0.357 0.000 0.577 4.456 6.580

3Q 1.001 0.009 0.378 0.384 0.000 0.671 5.597 8.040

4Q 0.690 0.093 0.165 0.358 0.000 0.391 3.043 4.740

Regional Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 5.520 3.924 2.649 7.158 0.097 2.892 8.052 30.292

2Q 11.162 0.114 1.987 1.140 0.026 1.218 2.425 18.072

3Q 15.827 0.030 2.199 1.223 0.038 1.406 3.334 24.057

4Q 6.915 5.755 3.513 11.620 0.089 3.995 11.931 43.818

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 3.873 3.752 2.242 5.642 0.080 1.185 6.959 23.733

2Q 4.071 0.541 1.406 0.896 0.024 0.531 2.085 9.554

3Q 4.675 0.072 1.503 0.878 0.031 0.681 2.993 10.833

4Q 4.062 4.377 2.498 9.488 0.084 1.678 10.372 32.559
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 36

Modeled CAMx quarterly average and high day (top 10%) average impacts for the Clairton 

receptors, by regional and local impacts, are given in Tables 5-9 and 5-10. Like with the Liberty 

impacts, the local and regional impacts were tracked separately by the CAMx model using the 

Particulate Source Apportionment Technology tool. The modeled impacts from point sources 

identified for local treatment are summed as the local portion of the CAMx impacts.

All values in Tables 5-9 and 5-10 are in μg/m3, with the species defined as follows:

SO4 = sulfate ion POA = primary organic aerosol

NO3 = nitrate ion SOA = secondary organic aerosol

NH4 = ammonium ion EC = elemental carbon

OTHER = unspeciated PM2.5

Table 5-9. Clairton Quarterly Modeled Averages (μg/m3)

Local Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 0.338 0.021 0.096 0.171 0.000 0.247 1.952 2.825

2Q 0.560 0.008 0.148 0.274 0.000 0.403 3.141 4.534

3Q 0.732 0.002 0.203 0.319 0.000 0.534 4.029 5.819

4Q 0.333 0.014 0.128 0.175 0.000 0.291 1.819 2.760

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 0.245 0.023 0.084 0.153 0.000 0.233 1.365 2.103

2Q 0.421 0.015 0.117 0.247 0.000 0.382 2.254 3.436

3Q 0.512 0.004 0.153 0.281 0.000 0.507 2.799 4.256

4Q 0.247 0.017 0.108 0.160 0.000 0.281 1.325 2.138

Regional Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 2.498 2.034 1.342 2.875 0.051 1.404 3.766 13.970

2Q 4.880 0.419 1.256 1.007 0.022 1.006 1.759 10.349

3Q 7.306 0.047 1.371 1.018 0.029 1.224 2.365 13.360

4Q 3.559 1.616 1.389 3.088 0.037 1.665 4.155 15.509

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 1.685 1.821 1.055 2.206 0.043 0.603 3.295 10.708

2Q 2.294 0.385 0.882 0.688 0.017 0.432 1.486 6.184

3Q 3.066 0.062 0.986 0.660 0.023 0.530 2.016 7.343

4Q 2.066 1.222 0.973 2.403 0.033 0.721 3.542 10.960
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 37

Table 5-10. Clairton Quarterly High Day Modeled Averages (μg/m3)

Local Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 1.590 0.114 0.438 0.752 0.000 1.028 9.296 13.218

2Q 1.443 0.016 0.336 0.671 0.000 0.851 8.368 11.685

3Q 1.578 0.005 0.515 0.605 0.000 1.080 9.552 13.335

4Q 1.007 0.071 0.527 0.538 0.000 0.998 5.510 8.651

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 1.071 0.134 0.374 0.615 0.000 0.837 5.741 8.772

2Q 1.244 0.031 0.342 0.744 0.000 0.973 7.188 10.522

3Q 1.345 0.007 0.477 0.734 0.000 1.343 8.194 12.100

4Q 0.692 0.092 0.419 0.454 0.000 0.836 3.491 5.984

Regional Impacts

2007 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 5.017 2.865 2.365 6.313 0.080 3.189 6.856 26.685

2Q 6.637 0.172 1.264 1.499 0.027 1.522 2.218 13.339

3Q 12.759 0.113 1.963 1.292 0.035 1.599 2.909 20.670

4Q 6.385 5.583 3.271 10.178 0.086 4.374 10.816 40.693

2014 SO4 NO3 NH4 POA SOA EC OTHER TOTAL

1Q 3.635 3.211 2.071 5.048 0.071 1.351 6.352 21.739

2Q 1.946 0.428 0.875 0.991 0.023 0.611 1.783 6.657

3Q 3.678 0.117 1.080 0.693 0.026 0.583 1.945 8.122

4Q 3.752 4.429 2.266 8.394 0.083 1.915 9.615 30.454

Model input/output and post-processing files can be obtained by request.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 38

5.5 Model Performance

Model performance review provides a method to examine modeled data in comparison to actual 

monitored data for the same timeframe. For the baseline 2007 case, model performance for 

Liberty was examined by ACHD and ENVIRON.

The EPA Modeling Guidance recommends performance statistics for use in operational 

evaluation of the modeled results. Equations for the Mean Fractional Bias (MFB) and Mean 

Fractional Error (MFE) metrics are given below:

Mean Fractional Bias (%)

Mean Fractional Error (%)

These equations were used to test the accuracy of the modeled results compared to the monitored 

data. “Goal” represents a good statistical relationship, while “criteria” represents average results 

(limits were used in regional model evaluations, given in the EPA Modeling Guidance). 

Statistics shown below in Table 5-11 were generated for total daily PM2.5 (all species).

Table 5-11. Statistics for the Modeled Daily Liberty Averages Compared to the Liberty 

FRM Values, Year-Round and by Season, 2007

Daily Results

Mean Fractional 

Bias

(MFB)

Mean Fractional 

Error

(MFE)

1

st Quarter 26.65% 42.53%

2

nd Quarter -24.21% 34.71%

3

rd Quarter -28.94% 38.93%

4

th Quarter 16.95% 40.05%

Year-Round -2.62% 39.03%

GOAL Within ± 30% ≤ 50%

CRITERIA Within ± 60% ≤ 75%
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 39

Positive MFB bias (MFE is always positive) indicates that the model overestimated in 1st and 4th

quarters, with the 2nd and 3rd quarters showing negative bias (underestimation). All quarters and 

year-round statistics fell within the goal range, indicative of good results.

Figure 5-9 shows a “soccer plot” that visually displays the daily statistics as data points within 

the goal and criteria ranges (red and blue boxes, respectively). All points lie within the “goal” of 

the soccer plot.

Figure 5-9. Liberty Daily Soccer Plot, Baseline 2007

A detailed report of model performance, including performance by individual species, is given in 

Appendix G-2.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 40

6 Attainment Tests

This section describes the calculations used for the attainment tests for Liberty and Clairton. 

Since the CAMx modeling provided modeled data on both total and regional/local bases, both 

options were tested for future attainment. Weighted values for 2005-2009 were used for this 

demonstration.

6.1 Monitored Data Assumptions

Speciation and PMF analyses (Appendix C) show that a diverse mix of PM2.5 components makes 

up the localized excess in the Liberty-Clairton area. The majority of the excess was measured as 

carbons, but other components such as ammonium sulfate and crustal component were also part 

of the excess.

The SANDWICH (sulfate, adjusted nitrate, derived water, inferred carbonaceous material 

balance approach) method outlined by EPA Modeling Guidance reconstructs PM2.5 species to 

better represent FRM monitored data. The SANDWICH species reconstructions are shown in 

detail in Appendix H (Attainment Tests). Using this technique, species are adjusted as follows:

 Nitrate is based on retained estimations

 Indirect ammonium is dependent on sulfate, nitrate, and degree of neutralization (DON) 

values

 Organic carbon is calculated by mass balance from all other species

 Water is calculated from sulfate, nitrate, and ammonium values

Assumptions are made with the monitored data handling to ensure that all species are accounted 

for and that the speciation data are correctly used for each FRM site. Assumptions for the CSN 

speciation and FRM data for Liberty and Clairton are listed below:

 Organic carbon mass by mass balance accounts for all differences between the FRM and 

other species and can include trace elements or other species that may be associated with 

organic carbon.

 Indirect ammonium best accounts for the ammonium and the calculated particle-bound 

water species. Any measured excess of ammonium may or may not be retained on the 

FRM filter and is accounted for in the organic carbon mass by mass balance. 

Furthermore, the ammonium generated by the CAMx model is based on associated 

sulfate and nitrate.

 “Other” component represents unknown mass from the speciation monitor. The 

SANDWICH technique recalculates most of the “other” component as particle-bound 

water associated with hygroscopic compounds.

 Liberty speciation data is assumed to be representative of both the Liberty and Clairton 

monitored areas. I.e., the Liberty species compositions are representative of Clairton but 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 41

at smaller overall concentrations. Liberty species compositions are therefore used with 

Clairton weighted FRM values in the design value calculation.

 No exceptional events or anomalies are evident in the FRM or speciation data. However, 

species mass balance problems led to the exclusion of two quarters of Liberty speciation 

data in the attainment test calculations.

 Degrees of Neutralization (DON) of sulfate are held constant for baseline to future case. 

DON has been supplied with the pre-calculated EPA speciation SMAT/MATS data set.

6.2 Annual Attainment Test Methodology

Speciated Modeled Attainment Test (SMAT) methodology for the annual standard is given in the 

EPA Modeling Guidance.19 Species reconstruction is based on the SANDWICH technique. The 

steps for the annual SMAT are listed below:

 Calculate 5-year weighted FRM quarterly averages. This is the average of the 2005-

2007, 2006-2008, and 2007-2009 3-year quarterly averages. This is done for the Liberty 

and Clairton FRM monitored values.

 Calculate retained nitrate (NO3r) by speciation sample. This has been provided as part 

of the SMAT/MATS data set, pre-calculated by EPA. The formula used for retained 

nitrate is shown below, as given in the EPA Modeling Guidance:

 Calculate quarterly averages of non-dependent species. Averages for nitrate, sulfate,

carbons, other primary PM2.5 (OPP), and concurrent FRM values are calculated. 

Quarterly averages for measured organic carbon are used for comparison to an organic 

carbon minimum (or OCfloor). Quarterly averages for DON are also calculated for use in 

the retained ammonium calculation.

 Calculate quarterly averages of retained ammonium (NH4r). Averages for retained 

ammonium are calculated from quarterly sulfate, nitrate, and DON averages. The 

formula is given below, as given in the EPA Modeling Guidance:

 

19 Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals 

for Ozone, PM2.5, and Regional Haze, EPA, April 2007.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 42

 Calculate quarterly averages of particle bound water (PBW). Averages for PBW are 

calculated from quarterly sulfate, retained nitrate, and indirect ammonium averages. The 

formula is given below for low acidity (DON >= 0.225), as given in the MATS User’s 

Guide:

S = SO4 / (SO4 + NO3r + NH4r)

N = NO3r / (SO4 + NO3r + NH4r)

A = NH4r / (SO4 + NO3r + NH4r)

 PBW = {202048.975 - 391494.647 *S - 390912.147 *N + 442.435 *(S**1.5) 

- 155.335 *(N**1.5) - 293406.827 *(A**1.5) + 189277.519 *(S**2) 

+ 377992.610 *N*S + 188636.790 *(N**2) - 447.123 *(S**2.5) 

- 507.157 *(S**1.5)*N - 12.794 *(S**3) + 146.221 *(N**1.5)*S 

+ 217.197 *(N**2.5) + 29.981 *(N**1.5)*(S**1.5) - 18.649 *(N**3) 

+ 216266.951 *(A**1.5)*S + 215419.876 *(A**1.5)*N 

- 621.843 *(A**1.5)*(S**1.5) + 239.132 *(A**1.5)*(N**1.5) 

 + 95413.122 *(A**3)} * (SO4+NO3r+NH4r)

 Calculate quarterly averages of organic carbon mass by mass balance (OCMmb). 

Averages for OCMmb are calculated from the concurrent FRM quarterly averages minus 

the sum of the other species. This accounts for material associated with organics and/or 

uncertainties in the measured species. The calculated organic mass is compared to the 

OCfloor to ensure that the mass balance method does not lead to lower concentrations than 

measured.

 Calculate quarterly species compositions; apply to weighted quarterly FRM averages. 

This is done by calculating fractions of the total (minus 0.5 passive blank mass) by 

individual species. For this step, the data is calculated twice to examine results by both 

total and by regional and local species. The species fractions are then applied to the 

weighted FRM values.

 Calculate quarterly Relative Response Factors (RRFs) from modeling. Direct RRFs are 

calculated from baseline and future CAMx modeled impacts for sulfate, nitrate, total 

organic aerosol (TOA), elemental carbon, and unspeciated PM2.5. For the total and 

regional/local options, this step is done twice.

NH4r = DON*SO4 + 0.29*NO3r
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 43

 Calculate future quarterly species averages from RRFs, re-calculate ammonium and 

PBW. The RRFs reduce the sulfate, nitrate, carbons, and OPP from the weighted baseline 

case values. Future case ammonium and PBW is calculated from the new quarterly 

averages. This step is performed twice to examine by both total and by regional and local 

species.

 Calculate the future design value. This is done by adding the future case species by 

quarter (plus 0.5 blank) and averaging the quarterly future FRM values, rounded to the 

nearest tenth for comparison to the annual standard. For an area with strong 

concentration gradients such as Liberty-Clairton, ACHD followed EPA Modeling 

Guidance by using a one-cell (single-site) analysis in place of a spatially-averaged array 

for the design values at Liberty and Clairton.

6.3 24-Hour Attainment Test Methodology

The Speciated Modeled Attainment Test (SMAT) for the 24-hour standard uses the same 

methodology as the annual standard for reconstruction of species and RRFs. But, modeled and 

observed concentrations are based on specific high day averages instead of quarterly averages.

 Indentify observed (monitored) high days in baseline timeframe. This is done by 

selecting the 8 highest days in each quarter over the 2005-2009 timeframe. (For Clairton, 

due to the 1-in-6 sampling schedule, only the 3 highest days per quarter were used.) This 

method focuses on high days that represent seasonal highs rather than overall maximums.

 Calculate quarterly species compositions for speciation high days. This is done using the 

same technique as the annual species compositions, but the quarterly averages are based 

on the highest 10% (3 samples were used per quarter) of speciation samples by overall 

concentration.

 Calculate weighted species compositions for baseline high days. This is done by using 

the quarterly species fractions for each of the high observed days. The end results are 

high day compositions per quarter for each year (2005-2009). Similar to the annual test, 

this step is done twice to examine the results by total and regional/local options.

 Calculate quarterly Relative Response Factors (RRFs) for high days from modeling. The 

high modeled days are identified after summing all components. Regional OPP is 

excluded from the total in this ranking method, due to overestimation of the modeled 

OPP.20 The top 10% (10 days) by quarter are then averaged for sulfate, nitrate, carbons, 

and OPP. RRFs are calculated from the baseline and future modeled results. For the 

total and regional/local options, this step is done twice.

 Calculate future high days from RRFs; re-calculate ammonium and PBW for each future 

high day. Using the same methodology as the annual test, high day species are reduced 

for the future case by the quarterly RRFs, and ammonium and PBW concentrations are 

 

20 This method was used in the Transport Rule (CSAPR) modeling (see References).
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 44

re-calculated from the future sulfate, nitrates. This step is performed twice to examine by 

both total and by regional and local species.

 Calculate future design value. The future projected high days are re-ranked by year, and 

the 98th-percentile value is identified for each year. The weighted 98th-percentile average 

is the average of the 2005-2007, 2006-2008, and 2007-2009 3-year averages, rounded to 

the nearest integer for comparison to the 24-hour standard.

6.4 Annual Attainment Test Results

A summary of the annual design value calculations for Liberty, by total species and by 

regional/local species, is given in Tables 6-1 and 6-2. Spreadsheets showing the expanded design 

value calculations are given in Appendix H. All compositions and design values are given in 

μg/m3, while RRFs are dimensionless ratios.

For the regional/local split option, local modeled carbons and unspeciated PM2.5 (OTHER) were 

summed as local primary material (LPM) and re-apportioned based on monitored compositions. 

This method better accounts for local primary modeled PM2.5 that may be overestimated as 

crustal component.

Table 6-1. Liberty Annual Attainment Test, by Total Species

Baseline 2007 Quarterly Compositions

QTR FRMw Blank Non-Blank OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 14.637 0.500 14.137 3.814 1.508 3.793 1.352 0.679 1.765 1.227

2Q 18.051 0.500 17.551 4.888 2.014 5.336 0.065 0.990 1.962 2.295

3Q 22.600 0.500 22.100 4.689 2.262 8.018 0.000 0.966 2.721 3.444

4Q 18.186 0.500 17.686 5.647 2.631 4.426 0.545 0.789 1.753 1.894

AVG 18.4

RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.804 0.501 0.690 0.893 0.851

2Q 0.746 0.531 0.500 0.956 0.827

3Q 0.721 0.545 0.450 1.304 0.816

4Q 0.817 0.513 0.605 0.766 0.830

Future 2014 Quarterly Compositions

QTR FRMf Blank Non-Blank OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 10.850 0.500 10.350 3.067 0.756 2.618 1.208 0.578 1.298 0.825

2Q 10.900 0.500 10.400 3.647 1.069 2.667 0.062 0.819 0.989 1.146

3Q 12.280 0.500 11.780 3.382 1.233 3.604 0.000 0.789 1.223 1.548

4Q 12.440 0.500 11.940 4.611 1.350 2.679 0.417 0.655 1.086 1.141

AVG 11.6
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 45

Table 6-2. Liberty Annual Attainment Test, by Regional/Local Species

Baseline 2007 Quarterly Compositions, Local

QTR OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 0.821 0.904 0.881 0.124 0.284 0.445 0.329

2Q 1.273 1.370 0.480 0.014 0.297 0.329 0.299

3Q 0.000 1.548 0.960 0.000 0.372 0.554 0.803

4Q 2.756 1.993 1.698 0.000 0.413 0.625 0.765

Local RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.811 0.811 0.821 1.209 0.811

2Q 0.837 0.837 0.851 1.815 0.837

3Q 0.827 0.814 0.802 2.396 0.814

4Q 0.800 0.800 0.802 1.379 0.800

Baseline 2007 Quarterly Compositions, Regional

QTR OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 2.993 0.604 2.912 1.228 0.395 1.319 0.898

2Q 3.615 0.644 4.857 0.051 0.693 1.633 1.996

3Q 4.689 0.714 7.058 0.000 0.594 2.168 2.641

4Q 2.892 0.638 2.728 0.545 0.376 1.128 1.129

Regional RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.798 0.437 0.674 0.891 0.878

2Q 0.704 0.386 0.470 0.939 0.849

3Q 0.665 0.394 0.420 1.264 0.858

4Q 0.811 0.434 0.581 0.761 0.860

Future 2014 Quarterly Compositions, Combined Regional and Local

QTR FRMf Blank Non-Blank OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 11.236 0.500 10.736 3.054 0.997 2.686 1.244 0.577 1.333 0.846

2Q 11.265 0.500 10.765 3.610 1.397 2.690 0.074 0.837 1.001 1.156

3Q 12.576 0.500 12.076 3.119 1.541 3.733 0.000 0.812 1.267 1.603

4Q 13.377 0.500 12.877 4.550 1.872 2.946 0.415 0.654 1.182 1.258

AVG 12.1

The Liberty annual attainment tests project a design value range of 11.6-12.1 μg/m3, below the 

standard of 15.0 μg/m3.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 46

A summary of the annual design value calculations for Clairton is given in Tables 6-3 and 6-4. 

Spreadsheets showing the expanded design value calculations are given in Appendix H. All 

compositions and design values are given in μg/m3, while RRFs are dimensionless ratios.

Table 6-3. Clairton Annual Attainment Test, by Total Species

Baseline 2007 Quarterly Compositions

QTR FRMw Blank Non-Blank OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 12.489 0.500 11.989 3.234 1.279 3.216 1.146 0.576 1.496 1.040

2Q 12.797 0.500 12.297 3.425 1.411 3.739 0.046 0.694 1.375 1.608

3Q 19.594 0.500 19.094 4.051 1.954 6.927 0.000 0.835 2.351 2.976

4Q 12.261 0.500 11.761 3.755 1.750 2.943 0.362 0.525 1.166 1.260

AVG 14.3

RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.776 0.507 0.681 0.897 0.815

2Q 0.730 0.578 0.499 0.934 0.763

3Q 0.706 0.590 0.445 1.340 0.753

4Q 0.787 0.512 0.594 0.760 0.815

Future 2014 Quarterly Compositions

QTR FRMf Blank Non-Blank OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 9.123 0.500 8.623 2.509 0.648 2.189 1.029 0.469 1.091 0.689

2Q 7.747 0.500 7.247 2.500 0.815 1.866 0.043 0.530 0.692 0.802

3Q 10.596 0.500 10.096 2.860 1.153 3.084 0.000 0.629 1.047 1.325

4Q 8.258 0.500 7.758 2.954 0.896 1.749 0.276 0.428 0.710 0.745

AVG 8.9
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 47

Table 6-4. Clairton Annual Attainment Test, by Regional/Local Species

Baseline 2007 Quarterly Compositions, Local

QTR OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 0.696 0.767 0.747 0.105 0.241 0.378 0.279

2Q 0.892 0.960 0.336 0.010 0.208 0.230 0.209

3Q 0.000 1.337 0.829 0.000 0.321 0.478 0.693

4Q 1.832 1.326 1.129 0.000 0.275 0.416 0.509

Local RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.739 0.739 0.725 1.109 0.739

2Q 0.755 0.755 0.752 1.804 0.755

3Q 0.746 0.735 0.700 2.123 0.735

4Q 0.773 0.773 0.743 1.235 0.773

Baseline 2007 Quarterly Compositions, Regional

QTR OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 2.538 0.512 2.469 1.041 0.335 1.119 0.761

2Q 2.533 0.451 3.403 0.036 0.486 1.144 1.398

3Q 4.051 0.617 6.098 0.000 0.513 1.873 2.282

4Q 1.923 0.424 1.814 0.362 0.250 0.750 0.751

Regional RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.769 0.430 0.675 0.895 0.875

2Q 0.685 0.429 0.470 0.918 0.845

3Q 0.653 0.433 0.420 1.309 0.853

4Q 0.779 0.433 0.580 0.756 0.852

Future 2014 Quarterly Compositions, Combined Regional and Local

QTR FRMf Blank Non-Blank OCMmb EC SO4 NO3r OPP NH4r PBWcalc

1Q 9.276 0.500 8.776 2.465 0.787 2.207 1.049 0.471 1.103 0.694

2Q 7.782 0.500 7.282 2.408 0.919 1.852 0.051 0.567 0.689 0.796

3Q 10.621 0.500 10.121 2.644 1.250 3.139 0.000 0.674 1.066 1.349

4Q 8.783 0.500 8.283 2.915 1.208 1.892 0.274 0.425 0.761 0.807

AVG 9.1

The Clairton annual attainment tests project a design value range of 8.9-9.1 μg/m3, below the 

standard of 15.0 μg/m3.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 48

6.5 24-Hour Attainment Test Results

A summary of the 24-hour design value calculations for Liberty is given in Tables 6-5 and 6-6. 

Spreadsheets showing the expanded design value calculations are given in Appendix H. All 

compositions and design values are given in μg/m3, while RRFs are dimensionless ratios.

Quarterly species compositions are calculated in a similar manner used in the annual test, but the 

results are applied to high days for each quarter instead of averages. RRFs are calculated by 

ratios of the modeled future case to baseline case results for high days. The future case results 

are then calculated by multiplying the baseline results by the corresponding RRF by species.

For the regional/local split option, similar to the annual results, local modeled carbons and OPP 

were summed as local primary material (LPM) and re-apportioned based on monitored 

compositions.

Table 6-5. Liberty 24-Hour Attainment Test, by Total Species

Baseline High Days

Baseline FRM High Days Year 2005 2006 2007 2008 2009

98th-Percentile 69.6 55.7 54.7 50.0 45.3

3-Year Design Values 3-Year Period Avg

2005-2007 60.0

2006-2008 53.5

2007-2009 50.0

5-Year Weighted Average 5-Year Period Avg

2005-2009 54

RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.796 0.485 0.712 0.963 0.815

2Q 0.824 0.614 0.402 4.326 0.807

3Q 0.795 0.678 0.334 2.600 0.920

4Q 0.820 0.467 0.610 0.767 0.830

Future High Days

Future Projected FRM High Days Year Year 1 Year 2 Year 3 Year 4 Year 5

98th-Percentile 41.5 35.6 32.0 31.7 31.1

3-Year Design Values 3-Year Period Avg

Years 1-3 36.4

Years 2-4 33.1

Years 3-5 31.6

5-Year Weighted Average 5-Year Period Avg

Years 1-5 34
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 49

Table 6-6. Liberty 24-Hour Attainment Test, by Regional/Local Species

Baseline High Days

Baseline FRM High Days Year 2005 2006 2007 2008 2009

98th-Percentile 69.6 55.7 54.7 50.0 45.3

3-Year Design Values 3-Year Period Avg

2005-2007 60.0

2006-2008 53.5

2007-2009 50.0

5-Year Weighted Average 5-Year Period Avg

2005-2009 54

Local RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.751 0.751 0.781 1.419 0.751

2Q 0.811 0.811 0.806 2.278 0.811

3Q 0.956 0.956 0.874 7.379 0.956

4Q 0.751 0.751 0.784 1.226 0.751

Regional RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.789 0.410 0.702 0.956 0.864

2Q 0.788 0.436 0.365 4.749 0.860

3Q 0.721 0.484 0.295 2.401 0.898

4Q 0.818 0.420 0.587 0.761 0.869

Future High Days, Combined Regional and Local

Future Projected FRM High Days Year Year 1 Year 2 Year 3 Year 4 Year 5

98th-Percentile 42.9 36.8 34.0 32.8 32.9

3-Year Design Values 3-Year Period Avg

Years 1-3 37.9

Years 2-4 34.5

Years 3-5 33.2

5-Year Weighted Average 5-Year Period Avg

Years 1-5 35

The Liberty 24-hour attainment tests project a design value range of 34-35 μg/m3, within the 

standard of 35 μg/m3.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 50

A summary of the 24-hour design value calculations for Clairton is given in Tables 6-7 to 6-8. 

Spreadsheets showing the expanded design value calculations are given in Appendix H. All 

compositions and design values are given in μg/m3, while RRFs are dimensionless ratios.

Table 6-7. Clairton 24-Hour Attainment Test, by Total Species

Baseline High Days

Baseline FRM High Days Year 2005 2006 2007 2008 2009

98th-Percentile 30.9 35.8 35.0 34.6 25.9

3-Year Design Values 3-Year Period Avg

2005-2007 33.9

2006-2008 35.1

2007-2009 31.8

5-Year Weighted Average 5-Year Period Avg

2005-2009 34

RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.803 0.519 0.712 1.123 0.749

2Q 0.800 0.668 0.395 2.445 0.848

3Q 0.752 0.719 0.350 1.052 0.814

4Q 0.827 0.512 0.601 0.799 0.803

Future High Days

Future Projected FRM High Days Year Year 1 Year 2 Year 3 Year 4 Year 5

98th-Percentile 17.6 19.2 17.4 20.2 14.8

3-Year Design Values 3-Year Period Avg

Years 1-3 18.1

Years 2-4 18.9

Years 3-5 17.5

5-Year Weighted Average 5-Year Period Avg

Years 1-5 18
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 51

Table 6-8. Clairton 24-Hour Attainment Test, by Regional/Local Species

Baseline High Days

Baseline FRM High Days Year 2005 2006 2007 2008 2009

98th-Percentile 30.9 35.8 35.0 34.6 25.9

3-Year Design Values 3-Year Period Avg

2005-2007 33.9

2006-2008 35.1

2007-2009 31.8

5-Year Weighted Average 5-Year Period Avg

2005-2009 34

Local RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.650 0.650 0.674 1.175 0.650

2Q 0.900 0.900 0.862 1.979 0.900

3Q 0.914 0.914 0.852 1.494 0.914

4Q 0.679 0.679 0.687 1.291 0.679

Regional RRFs

QTR TOA EC SO4 NO3 OTHER

1Q 0.801 0.424 0.725 1.121 0.927

2Q 0.664 0.401 0.293 2.487 0.804

3Q 0.541 0.365 0.288 1.035 0.669

4Q 0.826 0.438 0.588 0.793 0.889

Future High Days, Combined Regional and Local

Future Projected FRM High Days Year Year 1 Year 2 Year 3 Year 4 Year 5

98th-Percentile 17.3 19.1 17.7 20.5 14.5

3-Year Design Values 3-Year Period Avg

Years 1-3 18.0

Years 2-4 19.1

Years 3-5 17.5

5-Year Weighted Average 5-Year Period Avg

Years 1-5 18

The Clairton 24-hour attainment tests project a design value of 18 μg/m3, below the standard of 

35 μg/m3.

Weight of evidence, as given in Section 9, provides additional assertions that the LibertyClairton area will demonstrate attainment of the NAAQS.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 52

6.6 Unmonitored Area Analysis

The EPA Modeling Guidance recommends examination of “unmonitored” areas for possible 

future exceedances of the NAAQS standards by employing a combination of interpolated 

monitored and modeled relative response ratios within spatial fields across the area.

The Liberty and Clairton Monitors are part of a complete network for Allegheny County –

according to monitoring network guidance21, there are no “unmonitored” areas. However, for a 

more complete analysis, ENVIRON generated grid concentrations using EPA’s MATS program

for 0.8 km grid cells surrounding and in between the Liberty and Clairton sites. ENVIRON 

applied MATS using its unmonitored area analysis feature to “spatially interpolate current year 

annual PM2.5 design value concentrations and project 2014 annual PM2.5 future design value 

concentrations throughout the 0.8 km and 4 km modeling domains using the CAMx 0.8 and 4 km 

modeling results, respectively.”

The analysis showed that no 0.8 km grid cell in the Liberty-Clairton area contained projected 

design values above the NAAQS. Details of the unmonitored analysis are given in Appendix G3.

 

21 EPA PM2.5 monitoring policy and guidance: http://www.epa.gov/ttnamti1/pmpolgud.html
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 53

7 Reasonably Available Control Technology and Measures

Reasonably Available Control Technology (RACT) and Reasonably Available Control Measures 

(RACM) for each PM2.5 nonattainment area require a demonstration that the agency has adopted 

all reasonably available control measures, including RACT for stationary sources, necessary to 

demonstrate attainment as expeditiously as practicable.

In determining whether a particular emission reduction measure or set of measures must be 

adopted as RACM, the agency must consider the cumulative impact of implementing the 

available measures. Potential measures that are reasonably available considering technical and 

economic feasibility must be adopted as RACM if, considered collectively, they would advance 

the attainment date by one year or more. 

The sole purpose of this RACT/RACM analysis is to determine if additional reasonable controls 

are available that could advance the attainment date by one year. These reviews should not and 

cannot be used by any source to satisfy any RACT analysis required by that source in a present 

or future permitting project.

Primary PM2.5 is the pollutant of concern in the Liberty-Clairton nonattainment area and was the

focus of the RACT/RACM analysis. Precursors SO2 and NOx were also reviewed for specific 

RACM options. Key RACT/RACM findings are included in this section, with further details of 

this analysis found in Appendix I.

RACT at U. S. Steel Mon Valley Works – Clairton Plant and Alternatives Considered

The U. S. Steel Clairton Plant is the largest source of PM2.5 located within the Liberty-Clairton 

area. Both U. S. Steel and ACHD separately reviewed the PM2.5 emissions units for the facility 

and found them to be satisfactory for this RACM demonstration.

As part of the Clairton Plant installation permit application for C Battery, U. S. Steel performed a 

Best Available Control Technology (BACT) analysis for all the affected emission units. The 

Clairton Plant batteries are of the conventional by-product coke oven type. The new installation 

of Battery C with the PROven system was determined to be BACT at the time. An alternative 

option of non-by-product recovery coke ovens using the Sun Coke Co. process and electric 

power generation was not considered technically feasible for integration into the other portions 

of the by-product coke oven plant. 

The coke oven batteries 7, 8, and 9 were shut down in 2009. Coke oven batteries 1-3, 13-15, 19-

20, and B have some of the nation’s strictest standards, either as ACHD Article XXI regulations 

or as permit conditions, so there were few alternatives to operational controls to be considered. 

Appendix I contains a detailed list of the controls by process.

For the new Quench Towers C, 5A, and 7A, double baffles are RACT versus alternative shorter 

quench towers with single baffles. Coke dry quenching (CDQ) was considered but found 

unacceptable for this project due to available space and cost. This was the same conclusion on 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 54

the other remaining quench towers. Other options were reviewed but would required extensive 

construction and installation costs. Included in this review were a “wet Low Emission Quench 

(LEQ),” a “ThyssenKrupp EnCoke World Steel, Bochum Coke Stabilization Quenching (CSQ) 

process,” a “Kress Indirect Cooling (KIDC) system,” and others. 

Alternatives to such pushing emissions control are the use of a coke side shed enclosure vented 

to a control device or a mobile capture and control unit. However, the shed system is too costly 

and the mobile capture is not technically feasible for this SIP. For battery process upsets, the 

atmospheric venting of raw coke oven gas through by-pass/bleeder stacks is first passed through 

a flare system. The alternatives to this are to use either regenerative thermal oxidation or 

catalytic thermal oxidation; however, these alternatives are too costly to be feasible for this SIP. 

Similarly, the impacts from the emissions of Boiler #1, Boiler #2, R1 Boiler, R2 Boiler, T1 

Boiler, T2 Boiler, and the Desulfurization Plant Afterburner do not warrant additional control.

RACT at Koppers Industries, Inc. and Alternatives Considered

Koppers Industries, Inc. Clairton Plant is a chemical processing plant where crude coal tar is 

debenzolized and distilled into pitch and various other products such as creosote, carbon black 

oil, and refined chemical oil. 

For the tar refining process, gases from the fume vents, pressure reliefs, ejectors, chiller, and 

condensate separator are manifolded together and burned in the eight process heaters. As 

alternative controls, the fumes could be flared or catalytically oxidized – but neither of the two 

alternatives would result in added emission reductions. Flaring would be less efficient and 

catalytic oxidation is more costly, so they are unacceptable alternatives. 

When manufacturing the rod pitch, the process utilizes a pitch cooler and dryer. A low 

temperature pulse-jet baghouse is used to control particulate emissions from the two units. As an 

alternative, a wet scrubber could be utilized, but there would be an undesirable wastewater 

disposal problem without gaining any emission reduction advantage. 

RACT at Mid Continent Coal and Coke Co. and Alternatives Considered

Mid-Continent Coal and Coke Company is a metallurgical coke breeze screening unit, serving 

the U. S. Steel Clairton Plant. Total PM2.5 emissions from this plant are less than 1 to 5 tons per 

year from all sources, including roads. No combination of sources that include this plant would 

advance attainment by a year.

The only emissions of interest from this plant are unpaved roadways. As alternatives, the 

roadway areas could have dust suppressant or watering; however, the emission reduction benefit 

from these alternatives is minimal because the amounts are small from the onset and the grounds 

tend to retain significant moisture. 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 55

RACT at Dura-Bond Coating Company and Alternative Considered

Dura-Bond Coating Company is a specialty coater of steel pipe. The pipe is intended for 

underground installation and is designed to withstand many years of use. The coating protects 

the steel pipe from moisture, thermal expansion, and other stresses. Total PM2.5 emissions from 

this plant are 1 to 5 tons per year from all sources.

RACT for this facility is: baghouses for powder coating line P001 shot blast pipe cleaners, 

powder reclaimer for powder coating operation PE1, baghouse for extruded polyethylene coating 

(X-Tec) line P003, gasoline storage tank conservation vent, watering roadways to limit road dust 

emissions, and catalytic retrofit and spark adjustment for forklifts. Since these RACT options 

are being implemented, no combination of sources that include this plant would advance 

attainment by a year. No additional RACT were considered for this facility.

RACT at Pennsylvania Electric Coil and Alternative Considered

Pennsylvania Electric Coil manufactures high voltage stator coils, up to 15Kv, as well as rotor, 

armature, field coils, and brake, magnet and specialty coils. The facility also repairs, rewinds, 

and remanufactures AC/DC motors, generators, and other types of apparatus, in shop or on site. 

Total PM2.5 emissions from this plant are less than one ton per year from all sources.

RACT for this facility is: integral afterburners for the burn-off ovens, cover for Safety-Kleen 

parts cleaner, cyclone used for the abrasive blasting operation, paint booth filters, baghouse for 

the tinning process, conservation vents for storage areas/tanks, and opacity monitoring for 

various processes. Since these RACT options are being implemented, no combination of sources 

that include this plant would advance attainment by a year. No additional RACT were 

considered for this facility.

RACT at Mon Valley Transportation Center, Inc. and Alternatives Considered

The Mon Valley Transportation Center, Inc. facility in Glassport, PA operates as a coal, coke 

and aggregate transshipment and storage facility. Total PM2.5 emissions from this plant are less 

than one ton per year from all sources.

RACT for this facility is: barge loader #2 water sprayer, railcar unloader water sprayer, covered 

conveyors, drop sleeves, catalytic retrofits and spark adjustments for diesel-fuel vehicles, 

watering storage piles, and watering and/or using dust suppressants on unpaved roadways. Since 

these RACT options are being implemented, no combination of sources that include this plant 

would advance attainment by a year. No additional RACT were considered for this facility.

RACT at AKJ Clairton LLC and Alternatives Considered

The AKJ Clairton plant is a sludge mixing operation facility that uses coal tar decanter sludge 

from the U. S. Steel Clairton Plant and different liquid diluents and a dispersant in a batch 

operation to produce liquefied coal waste sludge for re-use. PM2.5 emissions from this facility

are negligible (less than 0.1 ton per year).
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 56

RACT at Tech Met, Inc. and Alternatives Considered

Tech Met provides chemical milling services to a variety of aerospace, medical, and industrial 

customers. Total PM2.5 emissions from this plant are less than 1 to 5 tons per year from all 

sources, including roads. No combination of sources that include this plant would advance 

attainment by a year.

RACM at Nonpoint Sources

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

RACT/RACM several RACM options for area, nonroad, and mobile sources in the Liberty 

Clairton area. RACT/RACM and alternatives for point and nonpoint sources are summarized in 

Table 7-1 below. Additional details of the RACT/RACM analysis can be found in Appendix I.

Table 7-1. RACT/RACM and Alternatives Considered for the Liberty-Clairton Area

Source Reasonably 

Available Control 

Measure

Alternative(s) 

Considered

Remarks

U.S. Steel New Batteries and 

Quench Towers

No

Koppers Industries, 

Inc.

1) For tar refining, 

fumes are burned for 

process heat. 2) For 

making rod pitch, a 

cooler/dryer and 

baghouse used.

Flaring or catalytic 

oxidation, and wet 

scrubber, respectively.

Flaring less efficient, 

catalytic oxidation 

more costly, and 

scrubber creates 

wastewater problem.

Mid Continental 

Coal and Coke 

Company

Negligible PM 

emissions overall.

Roadway watering Grounds inherently 

retain water.

Dura-Bond Coating 

Company

Negligible PM 

emissions. RACT is 

baghouse, powder 

reclaimer, storage 

tank conservation 

vent, road watering.

No

Pennsylvania 

Electric Coil

Negligible PM 

emissions. RACT is 

afterburners, cover for 

cleaner, cyclone, paint 

booth filters, 

baghouse storage 

tanks conservation 

vents, and opacity 

monitoring.

No
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 57

Source Reasonably 

Available Control 

Measure

Alternative(s) 

Considered

Remarks

Mon Valley 

Transportation 

Center, Inc.

Negligible PM 

emissions. RACT is 

water sprayers for 

loaders/unloader, 

covered conveyors, 

diesel vehicle 

retrofits, water dust 

suppressant.

No

AKJ Clairton, LLC Negligible PM 

emissions.

No

Tech Met, Inc. Negligible PM 

emissions.

No

Restaurants –

commercial 

charbroiling

Currently no RACM. Rules to require 

charbroiler exhaust 

stack catalytic 

oxidizer s for chain 

driven broilers, and 

HEPA filters for 

under-fired broilers.

Full implementation 

could take five (5) 

years.

Residential Wood 

Burning –stoves and 

fireplaces

Currently no RACM. Woodstove exchange 

program, education & 

outreach on burning 

clean, curtailment of 

burning with expected 

high ambient levels of 

PM, and replacement 

of old stoves when 

homes are sold.

Options 1 and 3 have 

quantifiable 

emissions reductions, 

but time to 

implement is longer 

than needed. Option 

2 is difficult to 

quantify and Option 

4 does not generate 

significant 

reductions.

Residential Wood 

Burning – Wood 

fired boilers.

Currently no RACM. Compliance with state 

OWB regulation and 

curtailment of burning 

with expected high 

ambient levels of PM.

Option 1 does not 

produce significant 

emissions reductions, 

and time to 

implement Option 2 

is longer than 

needed.

Residential Coal 

Furnaces

Currently no RACM. Replace coal furnaces 

with natural gas or 

electric systems.

Coal furnace 

emissions are 

negligible.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 58

Source Reasonably 

Available Control 

Measure

Alternative(s) 

Considered

Remarks

Four Stroke Gasoline 

Lawnmowers

Currently no RACM. Gas for Electric 

mower trade program, 

Upgrade mower 

engine to higher Tier 

standards, native 

landscaping, and 

reduced commercial 

mowing.

Extremely small 

reductions for 

trading programs and 

commercial mowing 

reductions, and 

unquantifiable 

reductions from 

native landscaping.

Commercial 

Gasoline Leaf 

Blowers

Currently no RACM. Gas for Electric trade 

program.

Extremely small 

emissions reductions.

Commercial and 

Residential Gasoline 

Snowblowers.

Currently no RACM. Gas for Electric trade 

program.

Extremely small

emissions reductions.

On-road mobile 

sources

Currently no RACM. Diesel engine 

retrofits, expanded 

use of clean fuel, 

replacement of public 

or private fleets ahead 

of normal schedule.

Diesel Powered 

Construction 

Equipment

Idling restrictions in 

effect.

Diesel engine retrofits 

and engine 

replacement with 

higher Tier engine.

Cost of emission 

reductions can be 

expensive and 

relatively small total 

reductions.

Non-road Gasoline 

and Diesel 

equipment and 

vehicles

Currently no RACM. Expand the use of 

clean burning B20 

and E10.

Relatively small 

reductions.

Off-road Diesel 

Equipment

Currently no RACM. Emissions testing & 

repair/maintenance 

program, and roadside 

anti-smoke 

inspections.

There is not 

sufficient time to 

implement programs.

Recreational Marine 

Boats

Currently no RACM. Reduce emissions or 

accelerate retirement 

of high emitting boats.

Recreational boats 

are insignificant 

source in L-C area.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 59

Source Reasonably 

Available Control 

Measure

Alternative(s) 

Considered

Remarks

Diesel Powered 

Short-haul and Longhaul Trucks

Currently no RACM. Diesel retrofits or 

engine replacement, 

compliance with 

idling law, and 

emission/opacity 

testing.

Diesel Switcher 

Locomotives

Currently no RACM. Locomotive retrofit 

with Idle Reduction 

Technologies –

APU’s.

Replacement with 

new switchers.

Relatively low 

emission reduction 

for APUs. Cost is an 

issue for 

replacements.

Diesel Line-Haul 

Locomotives

Currently no RACM. Replacement of preTier 0 and Tier 0 

engines with Tier 2. 

Accelerated 

replacement with Tier 

4 locomotives.

First option – high 

cost. Second option 

has low impact 

because engines 

operate outside 

NAA.

Commercial Marine 

Vessels

Currently no RACM. Repowering from Tier 

0 to Tier 2 engines. 

Retrofit tugboats with 

diesel particulate 

filters. Control idling.

Idling restrictions are 

not workable since 

tugs are constantly 

deployed.

In summary, emission reductions needed to reach attainment in Liberty-Clairton are dependent 

primarily on shutdowns and modifications at the U. S. Steel Mon Valley Works – Clairton Plant. 

The proposed new configuration at the Clairton Plant will lead to a reduction of 284 tons per 

year, and the new equipment has already engaged reasonably or best available control 

technology. The projected Liberty-Clairton area beyond the Clairton Plant will total less than 62 

tons per year of primary PM2.5.

The finding of this analysis is that the identified RACMs (or combination thereof) for the 

Liberty-Clairton PM2.5 nonattainment area are not likely to advance the attainment date by one 

year or more. ACHD has, therefore, adopted RACT and RACM as defined for this PM2.5 SIP.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 60

8 Contingency Measures

As outlined in the PM2.5 Implementation Guidance,

22 PM2.5 contingency measures are additional 

control measures to be implemented in the event that an area fails to meet Reasonable Further 

Progress (RFP) or fails to attain the standards by its attainment date. RFP documentation is not 

required for this SIP since an extension of attainment date is not necessitated.

This attainment demonstration is based on a baseline year of 2007, with an attainment year of 

2014. Thus, the time period for the projected reductions is 7 years. Contingency measures are 

recommended to be based on approximately one year of additional emissions reduction.

The majority of reductions that are pertinent within the Liberty-Clairton area involve direct 

PM2.5 emissions. The reduction in PM2.5 for all source categories is 290.9 tons, as shown below 

in Table 8-1. While reductions of PM2.5 precursors are also projected, the size of the LibertyClairton area and nature of the localized excess necessitates reduction of the direct PM2.5 more so 

than the precursors.

Table 8-1. Calculation of Required and Excess Emission Reductions

Liberty-Clairton Area PM2.5 (tons/year)

Baseline (2007) Liberty-Clairton Area 

Emissions 997.8

Projected (2014) Liberty-Clairton Area 

Emissions 706.8

Change in Emissions -290.9

Target Reductions for Contingency 

Measures (1/7)

41.6

EPA Implementation Guidance states that contingency measures should consist of other control 

measures for the area that are not included in the control strategy for the SIP. This could include 

federal measures and local measures already scheduled for implementation, along with measures 

to be implemented if attainment is not achieved.

Should attainment not be achieved by December 2014, the consent order and agreement with 

U.S. Steel (as amended in September 2010 and July 2011) specifies the following: coke oven 

wall rebuilds for Battery 20 to be implemented in late 2014. U. S. Steel will replace 88 heating 

walls by October 31, 2014, and the battery will meet its opacity limits by December 31, 2014, 

including an advanced patching plan and a revitalization plan of the battery heating system, as 

 

22 Federal Register, Vol. 72, No. 79, Pages 20642-3, and EPA March 2, 2012 Memo from S. D. Page.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 61

necessary. Emissions reduced by the improvements to Battery 20 are expected to be 10.8 

tons/year.

Therefore, a minimum of an additional 30.8 tons/year reduction is required. To attain this 

reduction, the consent order and agreement with U. S. Steel (to be amended by Dec. 31, 2013) 

specifies the following: within 18 months after receiving notice from ACHD that EPA is 

requiring implementation of the contingency measures, U. S. Steel’s Clairton Plant will reduce 

emissions from the current Quench Tower 1 by 30.8 tons from emissions in the 2014 attainment 

demonstration inventory as modeled in this SIP; or implement emission reductions greater than 

or equal to 30.8 tons per year (unless a lesser amount is needed to demonstrate attainment of the 

2006 24-hour PM2.5 NAAQS).

Total emissions reductions from the contingency measures are given in Table 8-2.

Table 8-2. Contingency Measures Emission Reductions

Process

PM2.5 2014

Modeled 

Emissions Value 

(tons/year)

PM2.5

Contingency 

Value (tons/year)

PM2.5 Reduction 

(Inventory –

Contingency) Value 

(tons/year)

Battery 20 – Rebuilds, 

Combustion Stack 21.1 11.3 9.8

Battery 20 – Rebuilds,

Door Leaks 2.1 1.1 1.0

Quench Tower 1 65.5 34.7 30.8

Totals 88.7 47.1 41.6

The emissions reductions due to the contingency measures would be equal to 1 year’s worth of 

emissions reductions required by the attainment demonstration; therefore, the identified 

reductions satisfy the requirement for contingency measures.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 62

9 Weight of Evidence

EPA’s Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air 

Quality Goals for Ozone, PM2.5, and Regional Haze (2007) encourages the use of corroboratory 

analyses to support the modeled attainment demonstration. These analyses, collectively referred 

to as “weight of evidence” (WOE), help bolster the assertions that an area will achieve 

attainment in the allotted time.

9.1 Liberty-Clairton Monitored Data Trends

Allegheny County sites have shown decreasing trends for PM2.5 since 2000 (see Figures 2-3 and 

2-4). Figures 9-1 and 9-2 show annual and 24-hour design values for the Liberty and Clairton 

monitors over a 10-year timeframe, with linear regression trend lines extrapolating data to 2014 

(i.e., design values for 2012-2014).

Figure 9-1. Liberty and Clairton FRM Annual Design Values, with Trend Lines Extrapolated to 

2014
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 63

Figure 9-2. Liberty and Clairton FRM 24-Hour Design Values, with Trend Lines Extrapolated 

to 2014

Based on monitored data alone, Figures 9-1 and 9-2 show projected PM2.5 design values for 

Liberty and Clairton that are below the standards. Both sites show a long-term decline in PM2.5

concentrations that are statistically significant23. These trend lines do not account for any 

additional influences to future emission levels that are discussed in this SIP, such as the 

modifications at the U. S. Steel Mon Valley Works – Clairton Plant. 

9.2 Local Major Source Modifications

Major source modifications that were not included in the modeling demonstration will lead to 

additional reductions of background and/or direct emissions that affect the Liberty-Clairton area. 

These modifications include the following:

 U. S. Steel Mon Valley Works – Edgar Thomson Plant: U. S. Steel implemented 

enhanced operating and maintenance plans and installed upgrades to the Basic Oxygen 

Process (BOP) operations in 2009-2010. Reductions of pollutants due to these controls 

were not estimated for the modeling demonstration.

 

23 Based on EPA Region III’s R Analysis of the Liberty Clairton PM2.5 Area, 2012.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 64

 Bellefield Boiler: The Bellefield plant refueled its coal-fired boilers to natural gas in 

2009. Emissions reductions due to the fuel switch have been “banked” as emission 

reduction credits (ERCs) and were not included in the modeling demonstration.

 Eastman Chemical Resins, Inc.: In December 2011, Eastman entered into a consent 

decree and agreement with the U.S. Dept. of Justice, EPA, and ACHD to install VOC 

control equipment at its Jefferson Plant. Estimates of pollutant reductions due to these 

controls were not available for the modeling demonstration.

9.3 EGU Deactivations

Effective October 1, 2012, GenOn (now NRG) Energy deactivated the four coal-fired electric 

generating units (EGUs) located at the Elrama Power Plant, upwind of the Liberty-Clairton area. 

(At the time of this SIP submittal, the units were deactivated but not permanently retired.) 

Elrama emissions used in the future case modeling were based on CSAPR allocations.

Several additional coal-fired units in PA and surrounding states (OH, WV, and MD) were 

deactivated in 201224 but were included in the modeling demonstration at CSAPR emissions 

levels. Table 9-1 below provides details of the deactivated units.

Table 9-1. EGU Deactivations in 2012, PA and Surrounding States

Plant Owner/Operator State Unit(s) Capacity 

(MW)

Elrama GenOn Energy PA 1-4 460

Armstrong First Energy PA 1,2 243

Walter C Beckjord Duke Energy OH 1 94

Niles GenOn Energy OH 1,2 217

Bay Shore First Energy OH 2,3,4 495

Eastlake First Energy OH 4,5 837

Conesville AEP OH 3 165

Albright Mon Power WV 1,2,3 283

Willow Island Mon Power WV 1,2 189

R Paul Smith First Energy MD 3,4 115

Additional deactivations are expected in future years due to EPA’s Mercury Air Toxics 

Standards, increased natural gas production, and/or other factors. (See Section 5.3.5 for EGU 

emission projections through mid-2015.)

 

24 PJM Interconnection: http://www.pjm.com/~/media/planning/gen-retire/generator-deactivations.ashx

(as of Jan. 10, 2013)
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 65

9.4 Population Trends

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 9-3 below.)

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 of from the 1990-2000 period, 

which saw an average decrease in the nonattainment area of -6.6%. 

Decreasing populations signal less use of cars and a lesser need for school buses and other 

diesel-engine vehicles. Additionally, various consumption activities will decline (power use, 

water use, etc.), and lower amounts of waste will be produced. Combining all of this with the 

local and national regulations and trends toward more efficient and cleaner cars and fuels, it is 

expected that PM2.5 in the nonattainment area will reach levels lower than the models show.

Figure 9-3. Population Trends for Allegheny County, 2000-2010
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 66

9.5 Wood Stoves and Wood-Fired Boilers

Receptor modeling and source apportionment showed that vegetative burning is a contributor of 

PM2.5 at Liberty. (Source apportionment results can be found in Appendix C-2.) Fine particulate 

pollution producing wood burning stoves and outdoor wood-fired boilers are used throughout 

Allegheny County. Further work in this area, including federal and local regulations addressing 

wood-burning stoves and boilers, respectively, will reduce particulate pollution further in the 

nonattainment zone.

9.5.1 Wood Stoves

At the federal level, EPA has promulgated regulations establishing emissions limits for newly 

manufactured woodstoves. “EPA-certified” wood stoves can reduce particulate emissions 70-

80% per unit compared to an older, non-certified woodstove. Taking advantage of that, from 

2005-2007, ACHD participated in EPA’s Great American Wood Stove Changeout Campaign, 

replacing 176 older non-EPA certified woodstoves in Southwest Pennsylvania with new, cleaner 

burning “EPA-certified” units. According to EPA, changing out 20 wood stoves results in a net 

reduction of 1 ton of particulate matter pollution. While newly manufactured wood stoves have 

emission controls, older non-certified stoves continue to pollute the air and could be part of a 

future wood stove changeout campaign. 

Additionally, as of May, 2011, EPA drafted proposed revised New Source Performance 

Standards (NSPS) for residential wood heaters that will continue to reduce particulate pollution 

from wood stoves, leading to fewer emissions from future installations. 

ACHD conducted educational campaigns, covering the health effects and environmental impact 

of wood smoke, are ongoing. These include campaigns to inform municipalities about pollution 

from wood stoves, and their ability to curtail it, the availability of cleaner units, and encouraging 

clean burning practices among those who already own and operate wood stoves.

9.5.2 Outdoor Wood-Fired Boilers

Outdoor Wood-Fired Boilers (OWBs), also known as hydronic heaters, are another source of 

particulate pollution for the Allegheny County and Liberty-Clairton areas. Over the past five 

years, a voluntary federal program, a state regulation, and some local ordinances have been 

established in order to help control OWB generated pollution. 

EPA’ Voluntary Hydronic Heater Program, launched in 2007, provides a process for 

manufacturers to demonstrate that their “Qualified” models are 90 percent cleaner than older 

unqualified units. At the state level, 25 Pa. Code, Chapter 123.14, “Outdoor wood-fired 

boilers”, became effective on October 2, 2010, and regulates the use of OWBs in the 

Commonwealth. The rule prohibits the sale, purchase, and installation of an OWB unless it is a 

Phase II qualified OWB. The rule also requires that any new OWB be installed a minimum of 

50 feet from the nearest property line, and have a stack that extends at least 10 feet above the 

ground. There are also requirements that appropriate fuels be used, such as clean, dry wood or 

wood pellets.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 67

In 2012, ACHD added similar OWB regulations to Article XXI, along with a limited number of 

health enhancing revisions, including an increased setback requirement of 150 feet, additional 

stack height criteria, use restrictions on Air Quality Action Days, and the addition of simple 

reporting requirements at purchase time. An outreach campaign targeted at OWB manufacturers 

and distributors is planned to help educate potential buyers of the ACHD regulations they must 

be in compliance with. ACHD expects this to help prevent improper burning and excess 

pollution production.

In addition to the new regulation, Article XXI §2104.01, Visible Emissions, and §2104.04, Odor 

Emissions, are in place which are useful enforcement tools for managing wood burning stoves 

and boilers. The clean-burning educational campaigns ongoing at ACHD encourage all 

Allegheny County residents to consider how and what they burn and how it impacts their health 

and environment.

The implementation of the OWB regulation by ACHD, and additional work including potential 

municipal ordinances regulating the use of wood-burning stoves and OWBs, will reduce 

particulate pollution further in the nonattainment zones.

9.6 Diesel Campaign

ACHD has a robust diesel reduction program that since 2004 has included the implementation of 

diesel idling regulations affecting school buses, trucks and transit buses, and off-road

construction-type vehicles and equipment. The program also has made available nearly $6.6 

million in funding for projects involving retrofitting or repowering of school buses, transit buses, 

and locomotive and construction equipment, as well as scientific studies of the extent and 

location of diesel particulate emissions.

In addition, the efforts of local environmental groups have been significant in developing new 

city and county laws and regulations, as well as non-governmental funding of several retrofit 

programs.

9.6.1 Idling

Idling regulations are currently in place at the state and county levels. On October 9, 2008, Act 

124, The Pennsylvania Diesel-Powered Motor Vehicle Idling Act, was signed by Governor 

Rendell. It became effective on February 6th, 2009, prohibiting the owners and drivers of any 

commercial diesel-powered on-road motor vehicle with a gross weight of greater than 10,001 

pounds from idling for more than five minutes in any 60-minute period. Exemptions are in place 

for the operator’s safety and the comfort of passengers in high or low temperatures. Extensive 

signage requirements in the law have been integral in spreading the news of this new regulation 

across the state. All truck docks and other places where diesel trucks may park or idle are 

required to post signs regarding the regulation. 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 68

In addition to the coverage of the State Act 124, Allegheny County has passed and has on the 

books, effective May 1, 2010, §2105.93 of Article XXI, “In-Use Off-Road Diesel Powered 

Mobile Equipment Engine Idling,” which prohibits idling of off-road vehicles for more than five 

consecutive minutes, unless exempt. Operators of such vehicles can be reported to ACHD and 

can be fined up to $500 if they are found in non-compliance. The County regulation primarily 

affects construction vehicles, which can operate as a nuisance point source at construction sites 

in highly populated areas. An extensive outreach campaign was conducted by Allegheny County 

to help owners and managers inform their employees of the regulation to avoid fines and to avoid 

producing excess pollution.

9.6.2 City Legislation & Industry Initiatives

In 2011, The City of Pittsburgh passed the Clean Air Act of 2011, which required certain 

publicly subsidized construction projects in Pittsburgh to utilize clean diesel equipment. This 

legislation will help to reduce diesel particulate pollution from construction projects in the city, 

both by the direct requirement for retrofitted equipment, and the incentives construction 

companies now have to retrofit their equipment in advance of securing a contract for a publicly 

subsidized project, so as to remain competitive. Local nonprofits have begun to work to pass 

similar legislation covering Allegheny County.

Other similar efforts to address diesel particulate pollution from construction sources have been 

taken up by local businesses and other organizations. In 2011, The University of Pittsburgh 

Medical Center (UPMC) established language for all future contracts that requires all 

construction equipment used at any UPMC construction site to meet Tier 4 standards. This 

requirement went into effect in the spring of 2011, three years before EPA will require Tier 4 

standards on all newly manufactured equipment. UPMC currently has several hospitals and other 

health facilities throughout Allegheny County and is the second largest employer in the 

Commonwealth.

9.6.3 ACHD/Heinz Endowment Retrofit Project

In 2011, ACHD initiated a project to provide funding to federally-registered small construction 

companies to help offset the costs of procuring certified and/or verified diesel retrofit 

technology. An amount of $925,000 was made available for the construction companies to 

purchase equipment, and ACHD selected the Mid-Atlantic Regional Air Management 

Association (MARAMA) to manage the project. A local philanthropic organization, the Heinz 

Endowments, matched ACHD’s funds and doubled the amount of money for MARAMA to 

distribute to construction companies in Allegheny County. ACHD’s portion of the funding is to 

be spent retrofitting equipment in Allegheny County. The Heinz Endowment’s portion will go 

toward helping construction companies comply with the above-mentioned City of Pittsburgh’s 

Clean Air Act of 2011.

Applicants will receive between $10,000 and $100,000 each, if selected. The costs of diesel 

particulate filters (DPFs) will be covered 100% and companies will receive up to 75% of the cost 

of engine repowers and rebuilds. ACHD and MARAMA expect somewhere between 15 and 20 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 69

individual companies to receive funding for various pieces of diesel-engine construction 

equipment.

9.6.4 Federally Funded Competitive ARRA Clean Diesel Retrofit Projects

The Allegheny County Health Department, with input from the Group Against Smog and 

Pollution (GASP) and Clean Water Action (CWA), applied for and was awarded federal funds 

for projects to reduce diesel particulate pollution in the spring of 2009. A total of $3,498,106 

was awarded by the U.S. EPA to the Department and funded four projects to help reduce diesel 

pollution in Pittsburgh, the Liberty-Clairton nonattainment area, and throughout Southwestern 

PA. The money came from the American Recovery and Reinvestment Act (ARRA) via the 

National Clean Diesel Program. The four projects, outlined below, were completed by 

September 2011.

 The Port Authority of Allegheny County used ARRA funds to assist in replacing two 

1996 model year transit buses with cleaner 2010 model-year diesel hybrid electric buses 

and to repower nine 2003 model year diesel buses with engines that met tighter 2007 

emission standards. This project reduces particulate matter pollution by approximately 

0.1 tons per year, carbon monoxide by 1.5 tons per year, and nitrogen oxides by 4.8 tons 

per year.

 The Constructors Association of Western Pennsylvania used ARRA funds to retrofit or 

repower 39 pieces of heavy-duty diesel-powered, non-road construction equipment in 

Western Pennsylvania. The various upgrades reduce particulate matter pollution by 9.4 

tons per year, carbon monoxide by 72 tons per year, hydrocarbons by 11.3 tons per year, 

and nitrogen oxides by 69 tons per year.

 Harsco Metals of Americas provides trucking for U. S. Steel. With ARRA funds they 

installed diesel particulate filters on eight dump trucks operating in and around U. S. 

Steel's Mon Valley Works. These trucks are now 90-percent less polluting than before 

the project. It is estimated that these diesel particulate filters will remove 0.02 tons of 

particulate matter per year, 0.20 tons of carbon monoxide per year, and 0.03 tons of 

hydrocarbons per year.

 CSX Transportation used ARRA funds to replace one vintage diesel switcher locomotive 

without emission controls with a two-engine configuration that has the latest in emission 

control technology. The GenSet switcher locomotive engine operates at CSX's 

McKeesport/Demmler rail yard, bringing immediate air quality benefits to the residential 

neighborhood nearby. The project cuts diesel particulate matter by approximately 0.5 

tons per year, carbon dioxide by 172 tons per year, and nitrogen oxides by 16.6 tons per 

year. It also saves 15,000 gallons of diesel fuel annually.

9.6.5 State Allocation Diesel Retrofit Project

ACHD also received $433,100 in funding from the Pennsylvania DEP to equip 33 of the City of 

Pittsburgh’s diesel-powered refuse haulers with diesel particulate filters. The money came from 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 70

the ARRA via the State Allocation Grant Program. Because of the frequent starting and stopping 

of the vehicles, and the proximity to all neighborhoods and families in the city, this project 

significantly helps local air quality. It is estimated that these diesel particulate filters will remove 

0.09 tons of particulate matter per year, 0.4 tons of carbon monoxide per year, and 0.1 tons of 

hydrocarbons per year. The project was completed in June 2010. A previous project led by 

GASP and Clean Water Action installed diesel particulate filters on 13 other City waste haulers, 

bringing the total number of diesel particulate filters installed to 46.

9.6.6 ACHD Clean Air Fund Retrofits

Through its Clean Air Fund, ACHD has completed the retrofit of 85 school buses and 11 pieces 

of municipal equipment, the latter were all at the City of Clairton. It is estimated that these 

diesel oxidation catalysts will remove 0.08 tons of particulate matter per year, 1.15 tons of 

carbon monoxide per year, and 0.42 tons of hydrocarbons per year. 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 71

9.7 Monitored Data During Low Production Periods

Economic recession in 2009 led to decreased levels of production at many industrial facilities in 

Southwest PA.25 To examine the effect of low production levels on PM2.5 concentrations, 2009 

continuous PM2.5 (TEOM) and Federal Reference Method (FRM) data were compared to 

previously monitored data for previous years. Liberty data was compared to Lawrenceville data 

to reveal differences between the regional and localized components. (Note: TEOM monitors 

are not considered “official” PM2.5 monitors by EPA but can be used for short-term trends and 

for real-time reporting of data. Data shown here has not been corrected to make FRM-like.)

Long-term hourly averages for the continuous TEOMs are shown in Figure 9-4 for Liberty and 

Lawrenceville during the period of 2000-2008. Hours are given according to Eastern Standard 

Time (EST).

Figure 9-4. Long-Term Hourly PM2.5 TEOM Averages at Liberty and Lawrenceville, 2000-

2008

 

25 Also note that, in general, much of the Midwest was a bit cooler and wetter than normal in 2009. 

However, NWS records for Pittsburgh International Airport indicate that closer to the Liberty-Clairton area, 

the average annual temperature was near normal and total annual precipitation was near or substantially 

below normal in 2009.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 72

Long-terms trends show that Liberty TEOM concentrations are much higher than Lawrenceville 

during nighttime hours but are nearly similar during daytime hours (specifically during afternoon 

to early evening hours). This diurnal trend is due to the strong influence of inversions that lead 

to the nighttime accumulation of particles in the Liberty-Clairton area. Smaller peaks can be 

seen at Lawrenceville due during peak traffic periods, also possibly influenced by inversions.

Long-term hourly averages (2000-2008) at each site were compared to averages for 2009 data. 

The Liberty long-term averages are shown along with 2009 averages in Figure 9-5 below.

Figure 9-5. Hourly 2009 PM2.5 TEOM Averages at Liberty Compared to Long-Term 2000-2008 

Averages

Liberty TEOM data show the same diurnal trend in 2009 as in previous years but at lower 

concentrations. Additionally, the dotted high-low lines visually indicate a higher nighttime 

difference between long-term and 2009 data. This is evidence that the 2009 low-production 

conditions led to lower concentrations during typical peak periods, supporting the control 

strategy addressed in this SIP.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 73

The Lawrenceville long-term averages are shown along with 2009 averages in Figure 9-6 below.

Figure 9-6. Hourly 2009 PM2.5 TEOM Averages at Lawrenceville Compared to Long-Term 

2000-2008 Averages

Lawrenceville TEOM data show an overall decrease in concentrations in 2009, with the high-low 

lines showing a slightly higher difference between long-term and 2009 daytime concentrations.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 74

Decreases in overall concentrations at both sites can be due to regionally lower production 

levels, while lower nighttime levels at Liberty may be evident of lower local source production 

levels. To examine this, differences in concentrations between the two sites were calculated.

Table 9-2 below shows quarterly average FRM data over a 5-year timeframe for years 2005-

2008 and for 2009. Averages are given for Liberty, Lawrenceville, and the difference between 

the two sites (Liberty minus Lawrenceville).

Table 9-2. PM2.5 FRM Quarterly Averages, 2005-2008 and 2009

Liberty 1Q 2Q 3Q 4Q

2005-2008 Average 14.9 19.1 23.6 18.9

2009 15.0 13.7 15.1 16.4

Lawrenceville 1Q 2Q 3Q 4Q

2005-2008 Average 12.5 13.8 19.4 12.3

2009 12.7 11.2 12.9 9.7

Difference (Lib.-Law.) 1Q 2Q 3Q 4Q

2005-2008 Average 2.4 5.2 4.2 6.6

2009 2.3 2.5 2.2 6.7

The difference parameters for 2nd and 3rd quarters in 2009 are significantly smaller than in 

previous years, coinciding with low production levels at local sources.

At the U. S. Steel Mon Valley Works – Clairton Plant, Batteries 13-15 were idled from Mar.-

Dec. 2009, along with B Battery from Apr.-Jun. 2009, due to economic recession. Batteries 7-9 

were also permanently idled in April 2009. At the NRG Elrama power plant, all boiler units 

operated at an average capacity of 8.1% from March to October 2009.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 75

To further illustrate the lower localized source influence in 2009 data, a plot of the LibertyLawrenceville TEOM difference is shown in Figure 9-7 for 2009 and previous years. For this 

chart, long-term hourly averages for 2000-2008 are compared to hourly averages for 2009. The 

hours have been shifted by 12 hours to show the nighttime period in the center of the chart.

Figure 9-7. Hourly 2009 PM2.5 TEOM Average Differences Between Liberty and 

Lawrenceville Compared to Long-Term 2000-2008 Data

The nighttime peak in the Liberty-Lawrenceville difference has been lowered in the 2009 data, 

reflecting the influence of reduced production in 2009 compared to that of normal production in 

2000-2008. Decreases in concentration differences are greatest in the late evening/early morning 

period.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 76

10 Emergency Episodes

Subpart H of 40 CFR part 51 specifies requirements for SIPs to address emergency air pollution 

episodes in order to prevent air pollutant levels from reaching levels determined to cause 

significant harm to the health of persons. No levels are currently recommended by EPA for PM2.5

emergency episodes, however ACHD Rules and Regulations Article XXI §2106.03, which 

defines the procedures for emergency air pollution episodes as well as the values for air 

pollutants, includes PM10 levels. ACHD will use the levels set for PM10 as PM2.5 levels. 

ACHD assumes one μg/m3of PM2.5 to be equal to at least one μg/m3of PM10, therefore if any 

PM2.5 monitor exceeds any of the levels listed for PM10, it will be assumed that the PM10 levels 

have been exceeded, and appropriate action will be taken according to the predetermined 

Episode Actions of Article XXI §2106.04.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 77

11 Legal Documents

11.1 Notice of Public Hearing and Comment Period
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 78

11.2 Transmittals of Hearing Notice to PA DEP and EPA
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 79
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 80

11.3 Proof of Publication and Certification of Public Hearing
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 81
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 82

11.4 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

Liberty-Clairton PM2.5 Attainment Plan, 2006 NAAQS

February 19, 2013 Public Hearing

Public Comment Period ending March 5, 2013

GENERAL

Comments related to the PM2.5 SIP in general.

1. Comment: Coal coke smell is evident throughout Liberty Borough. Liberty and surrounding 

communities deserve the strongest level of protection possible.

Commenter: Reverend Don Polito, Pastor, Liberty Presbyterian Church.

Response: ACHD appreciates the comment and will continue to work on air quality plans in 

order to protect the community.

2. Comment: Evidence suggests that daily peaks of pollution in the Mon Valley are triggering 

asthma attacks, other lung diseases, and heart attacks. If residents are asked to reduce emissions on 

bad air quality days, industry should be asked to curtail emissions on those days as well.

Commenter: Clean Water Action.

Response: A SIP is a plan developed to meet attainment of NAAQS to protect public health. 

On Air Quality Action Days, both the public and industry are requested to minimize 

emissions. ACHD will continue to work on air quality plans in order to protect the 

community.

3. Comment: The SIP shows future design values that are close to the NAAQS. ACHD should 

closely monitor emissions and take aggressive action should attainment not be met. U. S. Steel 

should be applauded for their actions to date but also asked to continue the installation of newer 

technologies such as low-emission quench towers.

Commenter: Clean Water Action.

Response: ACHD will continue to monitor the air in Allegheny County and work with 

industry and other pollutant sectors in order to control emissions.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 83

4. Comment: Although the SIP shows a decrease in particulate matter, the SIP does not address the 

exposure to volatile carcinogenic gases from the coke plant. Daily exposures to these emissions 

should be made publically available, especially for peak periods.

Commenter: Constance Jennings, MD.

Response: This plan is only for the control of fine particulates. However, up-to-date 

information on monitored data is available at the ACHD web site: 

http://www.achd.net/air/index.php.

5. Comment: The Mon Valley has a high rate of heart attacks and cancer due to airborne 

particulates. Laws for the control of particulates from vehicles and off-road equipment are not 

being enforced. Also, ACHD should develop a prevention and testing program for toxics such as 

mercury and arsenic, similar to lead testing for children.

Commenter: William Donofrio, Your Environment.

Response: ACHD appreciates the recommendation and will continue to work on air quality 

plans and prevention programs in order to protect the community. The comment related to 

enforcement of particulate matter from vehicles and off-road equipment may relate to the City 

of Pittsburgh’s “Clean Air Act of 2010,” which is not applicable to the Mon Valley.

6. Comment: Clean air should be a priority for SWPA, plans for air quality should be continued, and 

current regulations should not be weakened. 

Commenter: Joan Smith; and Christopher D. Conte.

Response: ACHD follows all national air quality rules and regulations and will continue to 

implement local regulations and programs for better air quality. No regulation has been 

weakened in this plan.

7. Comment: On Jan. 4, 2013, the U.S. Court of Appeals for the District of Columbia Circuit (D.C. 

Circuit) remanded to EPA the Final Clean Air Fine Particle Implementation Rule. The D.C. 

Circuit found that EPA erred in the implementation of the 1997 PM2.5 NAAQS according to 

Subpart 1 of Part D of Title I of the Clean Air Act, rather than Subpart 4. EPA is still interpreting 

this court decision and its potential implications for attainment demonstrations.

Commenter: U.S. EPA Region III.

Response: ACHD acknowledges the court ruling and will work with EPA in response to 

potential implications to the attainment demonstration. ACHD believes the requirements of 

both Subpart 1 and Subpart 4 have been satisfied (see responses to comments 8 and 27). 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 84

8. Comment: Based on the Jan. 4, 2013 D.C. Circuit ruling, the Liberty-Clairton SIP should comply 

with Title I, Part D, Subpart 4 of the Clean Air Act. The SIP must be revised to reflect the 

requirements applicable to moderate areas under Subpart 4. This includes a due date of June 14, 

2011, an attainment deadline of Dec. 31, 2015 without contingency measures, compliance with 

RACM by Dec. 14, 2013, and presumptive regulation of VOCs and NH3.

Commenter: Clean Air Council, PennFuture, GASP, Clean Water Action, Sustainable 

Pittsburgh, Sierra Club, REACH Mon Valley, and Center for Coalfield Justice.

Response: With addition of discussion of VOCs and NH3, ACHD believes the requirements 

of both Subpart 1 and Subpart 4 have been satisfied. (See also response to previous comment

and comment 27.)

9. Comment: The Liberty-Clairton area is at high risk of being reclassified as a “serious” 

nonattainment area under Title I, Part D, Subpart 4 of the Clean Air Act if attainment is not met. 

The attainment demonstration shows no practical support for its conclusion that will attain the 24-

hour standard by Dec. 14, 2014. The lack of federally enforceable commitments and reductions 

beyond 2011 will likely lead to nonattainment and reclassification to “serious” by EPA.

Commenter: Clean Air Council et al.

Response: ACHD is confident that attainment will be reached with this SIP.

10. Comment: The executive summary should include the revised PM2.5 NAAQS, especially since 

the projected design values are near or below the new 12 μg/m3 annual standard. 

Commenter: U. S. Steel Corporation.

Response: This SIP is specific to the 2006 NAAQS and provides an attainment 

demonstration to those standards only. The 2012 NAAQS will be addressed in future 

demonstrations.

PROBLEM STATEMENT

Comments related to the description of the Liberty-Clairton PM2.5 problem.

11. Comment: Lawrenceville data is used in the analysis of regional PM2.5 concentrations. 

Lawrenceville does not represent background conditions for Allegheny County or the LibertyClairton Area. Averaging Lawrenceville speciation data with Florence and Greensburg data may 

be skewing the calculated excess at Liberty. Additionally, Liberty data should not be considered 

uncommon to SWPA since its species composition is similar to other sites.

Commenter: U. S. Steel Corporation.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 85

Response: The Speciation Report in Appendix C-1 helps explain the regional and local 

analysis. The purpose of the analysis is to separate Liberty-dominant species from the more 

widespread species. Lawrenceville is typically representative of urban excess emissions but 

is also part of the regional component. Averaging Lawrenceville with Florence and 

Greensburg for the regional component minimizes site influences at each monitor, and the 

average of the 3 sites is the best representation of SWPA air surrounding the Liberty-Clairton 

area.

For the calculations used in the attainment tests, speciation data is combined with FRM data 

using the SANDWICH technique, which adjusts the species compositions. Figures 4-1 and 

4-5 in Appendix C-1 show that the SANDWICH technique produces nearly identical species 

concentrations for the Lawrenceville, Florence, and Greensburg sites on both long-term and 

high-day bases.

Although the species are the same, the Liberty data is considered to be uncommon to SWPA 

because it shows species concentrations that are specific to a smaller area. It is not a highestconcentration monitor that is consistent with air throughout the SWPA air shed; rather, it 

represents a portion of long-range transport and urban PM2.5 along with a localized 

component. This concept is part of the basis for designating Liberty-Clairton as a separate 

area within Allegheny County.

12. Comment: Figures 2-3 and 2-4 should indicate if there are any monitors that collected insufficient 

data to calculate a valid design value, in accordance with 40 CFR Part 50 Appendix N.

Commenter: U.S. EPA Region III.

Response: Figures 2-3 and 2-4 have been noted accordingly. Appendix B has been revised 

to include details of the incomplete data and attainment status of each monitor, as taken from 

the EPA design values web site (http://www.epa.gov/airtrends/values.html). The Liberty 

monitor satisfied all data requirements.

METEOROLOGY

Comments related to the meteorological analysis included in the SIP.

13. Comment: Figure 2-2 should note that hourly Tapered-Element Oscillating Microbalance 

(TEOM) monitor data and not Federal Reference Method (FRM) monitor data were used for the 

data shown in the figure.

Commenter: U.S. EPA Region III.

Response: Figure 2-2 has been noted accordingly.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 86

14. Comment: Section 2.3 mentions that meteorological data from Pittsburgh airport data is assumed 

representative of stability conditions throughout the county; but, the report referenced later in the 

section states that valley meteorology complicates the connection between emissions controls and 

air quality benefits.

Commenter: U. S. Steel Corporation.

Response: ACHD used the best available meteorological information deemed representative 

for the modeling demonstration. The closest, twice daily, National Weather Service (NWS) 

upper air data is collected near the Pittsburgh International Airport in Moon Township, PA, 

about 24 miles northwest of the U. S. Steel Clairton Plant. (Note that the NWS operates only 

about 70 upper air stations throughout the conterminous U.S.) For modeling purposes, this 

data is representative of the stability across Allegheny County. The meteorological 

evaluation given in Appendix A-1 took valley conditions into consideration by examining 

morning ground inversions beginning at 1oC in strength and assuming that valley areas on 

days when such PIT NWS inversions were present would also be experiencing significant 

inversions.

15. Comment: The SIP states that precipitation helps end a pollutant event. This should be revised to 

reflect that precipitation can help end an inversion, regardless of PM2.5 levels.

Commenter: U. S. Steel Corporation.

Response: Precipitation helps to end a pollutant event, regardless of whether an inversion is 

present or not. So, the statements in the SIP related to the effects of precipitation are 

appropriate.

16. Comment: ACHD historically and erroneously points to meteorology as a cause of 

nonattainment. While inversions may inhibit dispersion, nonattainment levels of PM2.5 are caused 

by emissions. If there were no emissions present, there would be no peak levels. Meteorology 

cannot be controlled; the direct relationship between source emissions and impacts must be the 

focus of SIP efforts.

Commenter: Clean Air Council et al.

Response: Inversions can lead to increased levels of pollutants anywhere in Allegheny 

County. In the case of the Liberty-Clairton area, nonattainment can be attributed to a 

combination of emissions, complex terrain, and meteorology acting together to trap 

pollutants in the area.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 87

CONTROL STRATEGY

Comments related to the controls used to show projected attainment.

17. Comment: The attainment plan includes emissions reductions of SO2 and NOx from the Cross 

State Air Pollution Rule (CSAPR) as a control measure. On August 21, 2012, The D.C. Circuit 

issued a decision to vacate CSAPR and to continue administering the Clean Air Interstate Rule 

(CAIR) for controls, pending the promulgation of a valid replacement. EPA is evaluating the 

ramifications of that decision and its potential implications for attainment plans. At this time, it is 

reasonable for the Liberty-Clairton attainment plan to rely on CAIR for the control of interstate 

emissions.

Commenter: U.S. EPA Region III; Clean Air Council et al.

Response: ACHD will rely on CAIR, state, and permit controls until a replacement for 

CSAPR is promulgated. However, at this time, ACHD believes that the inventory used in the 

federal CAIR modeling demonstration is an outdated inventory that may not adequately 

represent future emissions from the electric generating unit (EGU) sector; 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. See Section 3.1, Section 

5.3.5, and Appendix E-6 of the SIP for more details on the CAIR/CSAPR inventories.

18. Comment: ACHD cannot rely on expected emissions reductions from CSAPR that are not SIPapproved. Even if CSAPR was not vacated, ACHD would still be obligated to delineate the 

specific controls and limitations from each source.

Commenter: Clean Air Council et al.

Response: See response to previous comment.

19. Comment: Control measures contained in the consent order with U. S. Steel should be clearly 

identified in the SIP. The consent order should be attached to the plan as supporting information.

Commenter: U.S. EPA Region III.

Response: Control measures are listed in Section 3.2 of the SIP and, as stated, are included 

in a consent agreement that, in turn, is federally enforceable through the installation permit 

and Title V permit. The consent order agreement as of 2011 is provided as supplemental 

information in Appendix F-2.

20. Comment: ACHD must list each specific emissions reduction measure at the U. S. Steel Coke 

Plant and ensure that those provisions are federally enforceable.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 88

Commenter: Clean Air Council et al.

Response: See response to previous comment.

21. Comment: The consent order amendment date of July 2011 should be added to the SIP. 

Additionally, the consent order identifies that the consent order was entered into in response to 

visible emissions and opacity violations; U. S. Steel disagrees with this statement. 

Commenter: U. S. Steel Corporation.

Response: The consent order amendment date of July 2011 has been added to the SIP. 

Regarding the reason for the consent order, this order resolves several violations at the Mon Valley 

Works. Section 3.2 of the SIP has been revised for clarification.

22. Comment: The regional inventory controls must be federally enforceable. These controls are not 

listed in the SIP.

Commenter: Clean Air Council et al.

Response: The compliance modeling includes an expected actual emissions inventory, based 

on both federally enforceable local and regional controls, and, in the case of more distant 

sources, expected future activity. Appendix E-2 specifies in detail the controls used in the 

regional inventories. Section 3.4 of the SIP has been revised for further clarification.

23. Comment: Emissions reductions included shutdowns from local sources adjacent to the LibertyClairton area, including GM, Ryan Metals, and Precoat. These shutdowns must be permanent, 

enforceable and quantifiable. The SIP should include information to support the permanent 

shutdowns of these facilities, as well as quantification of the emissions reductions.

Commenter: U.S. EPA Region III; Clean Air Council et al.

Response: These facilities have been permanently shut down, without emissions credits or 

current operating permits. Any future operation at these locations would require a new 

permit and new source review. Additional language has been added to Section 3.3 of the SIP 

for clarification. Also, quantifiable emissions for Allegheny and Washington County 

facilities, base and future cases, have been added to Appendix F-2.

24. Comment: The SIP identifies the U. S. Steel Clairton Plant as the largest pollutant source. The 

SIP should be revised to state that the Clairton Plant is the largest known individual source in the 

Liberty-Clairton area, as the largest sources of pollutants are background and regional sources.

Commenter: U. S. Steel Corporation.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 89

Response: The SIP has been revised accordingly.

25. Comment: The Battery 19 discussion should be updated to state that 25 heating walls were 

replaced by 2012, and if necessary, an advanced heating plan will be implemented to reduce 

emissions.

Commenter: U. S. Steel Corporation.

Response: The SIP has been revised accordingly.

26. Comment: Based on emissions inventory, U. S. Steel’s Clairton Plant is the primary influence on 

ambient air in the Liberty-Clairton area. Controls must be in place in a timely fashion, as there are 

no further reductions planned beyond 2013.

Commenter: Clean Air Council et al.

Response: The attainment demonstration is based on controls from both the local and 

regional sources of PM2.5. The primary influence on the ambient air in SWPA is regional 

(incoming) air pollution. The largest controls locally in Liberty-Clairton are for the Clairton 

Plant. The projected year of attainment is 2014, so reductions beyond that have not been 

considered for this SIP.

EMISSIONS INVENTORY

Comments related to the pollutant inventories used for the baseline and projected 

emissions.

27. Comment: Emissions inventories for the base and projected years show decreases of PM2.5 and its 

precursors. Address or elaborate on why control measures were needed for PM2.5, SO2, and NOx

and not for VOC and NH3.

Commenter: U.S. EPA Region III.

Response: Direct PM2.5 represents the largest amount of localized excess at Liberty monitor, 

while regional sulfates and nitrates are the largest portions of the regional component of 

PM2.5 in SWPA. Controls for these pollutants lead to the largest reductions in SWPA and the 

Liberty-Clairton area. While not the focus of the control strategies, Tables 4-1 and 4-2 also 

show reductions for VOC and NH3 for the Liberty-Clairton area.

Additionally, VOC emissions showed negligible transformation to secondary organic 

aerosols (SOA) in the CAMx model, both regionally and locally. NH3 emissions also 

showed little transformation to NH4 not associated with sulfates and nitrates (see Section 5.4 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 90

of the SIP). Therefore, additional control of these precursors is unlikely to show reductions 

in the modeled impacts. 

28. Comment: The PM2.5 emissions provided in Table 5-1 for the Mitchell and Elrama power plants 

do not match those reported in PA DEP’s eFACTS system. Elaborate on this discrepancy.

Commenter: U.S. EPA Region III.

Response: Some reported PM2.5 2007 facility emissions in the eFACTS system do not 

include or are erroneous for the condensable portion of PM2.5. Condensable PM2.5 emissions 

were included in the 2007 MANE-VU inventory used in the modeling, as calculated 

according to the TSD in Appendix E-1, similar to other inventories such as the National 

Emissions Inventory (NEI).

29. Comment: More recent emissions data should be used for power plants on “long term cold 

storage” for future modeled projections.

Commenter: Clean Air Council et al.

Response: Unless permanently retired with PJM Interconnection, power plants proposed for 

deactivation were kept in the future case inventory. The future case modeling simulation 

may therefore be considered conservative for power plant impacts. Discussion of the 

proposed deactivations in 2012 was included as weight of evidence.

MODELING

Comments related to the methodology used for modeling and the resulting modeled 

impacts.

30. Comment: The explanation of the selection of the nearby receptors used in the modeling is 

unclear. It is also unclear if the receptor selection is similar to the process described in Section 3.2 

of the EPA Modeling Guidance.

Commenter: U.S. EPA Region III.

Response: The selection of the nearby receptors for Liberty and Clairton is described in 

more detail in the Modeling Protocol (Appendix G-1). The selection of the receptors varies 

somewhat from the method described in Section 3.2 of the EPA Modeling Guidance, as the 

Liberty-Clairton attainment tests were more of a local area analysis than a grid cell analysis. 

The selection of receptors for the FRM locations were based on the extent of concentrations 

contours seen in previous modeling efforts.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 91

31. Comment: Additional language would be helpful in Section 5 to explain the construction of the 

local and regional modeled impacts shown in Tables 5-7 through 5-10.

Commenter: U.S. EPA Region III.

Response: The local and regional impacts were tracked separately by the CAMx model 

using the Particulate Source Apportionment Technology tool. The modeled impacts from 

point sources identified for local treatment are summed as the local portion of the CAMx 

impacts. Additional language has been added Section 5 to further explain the treatment of 

the local and regional impacts.

32. Comment: It is unclear if the Relative Response Factors (RRFs) used for the unmonitored area 

analysis were calculated from a single grid cell or from a combination of grid cells around the 

Liberty and Clairton monitors.

Commenter: U.S. EPA Region III.

Response: The unmonitored area analysis is described in more detail in Appendix G-3. The 

unmonitored analysis was performed using the EPA Modeled Attainment Test Software 

(MATS) using the default options. The RRFs were based on modeled results for each single 

grid cell, with the design values spatially interpolated based on the modeled gradients.

33. Comment: Meteorological conditions in 2007 are not representative of maximum PM2.5

concentrations. The maximum concentrations given in Table 2 of Appendix A are higher in 2005, 

2006, and 2009 than the maximum concentration in 2007.

Commenter: Clean Air Council et al.

Response: The baseline year 2007 was chosen because it was a recent year in which a 

complete and verified national emissions data set was available from Regional Planning 

Organizations (RPOs) and represented typical meteorology, developed specifically for PM2.5

and ozone demonstrations. The inventories were reviewed for SIP-quality and were 

considered the best available at the time of the modeling for this SIP.

Monitored data shows that 2007 is typical of high PM2.5 days for the 5-year weighted 

timeframe of 2005-2009. The attainment tests outlined in EPA Modeling Guidance are based 

on a 5-year weighted methodology, and the baseline year is used to represent a 5-year 

timeframe. Year 2007 contains the second highest amount of days with concentrations 

greater than or equal to 35.5 μg/m3 (the level at which an exceedance of the new standard 

may be registered) and the most consecutive days greater than or equal to 35.5 μg/m3. 

Additionally, the 24-hour attainment test is based on averages of the 98th-percentile values, 

not maximum values. The 98th-percentile concentration for 2007 was 54.7 μg/m3, which is 

close to a midpoint between 2005 and 2009 (98th-percentile values of 69.6 μg/m3and 45.3 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 92

μg/m3, respectively). Thus, year 2007 is an appropriately representative year over the 5-year 

timeframe for PM2.5 concentrations.

34. Comment: ACHD has partially double-counted emissions reductions from controls and 

shutdowns occurring in 2009.

Commenter: Clean Air Council et al.

Response: The attainment demonstration uses a baseline modeled year of 2007 applied to a 

weighted timeframe of 2005-2009 according to the methodology outlined in the EPA 

Modeling Guidance. There is inherently some under- and over-counting in the combination 

of modeled impacts (based on 1 year of emissions) with monitored impacts (based on 5 years 

of monitored data), and the local source shutdowns occurred for only a portion of 2009. 

Since the modeled/monitored results are combined in a relative sense (see also responses to 

comments 35 and 37), these discrepancies would not adversely impact the modeling 

demonstration.

35. Comment: The WRF meteorological model failed the performance benchmarks by 

overestimating winds. Overestimation of winds can lead to underestimation of PM2.5 impacts.

Commenter: Clean Air Council et al.

Response: The WRF model is a state-of-the-science meteorological model appropriate for 

air quality modeling use. The benchmarks presented on the soccer plots in Appendix G-2 are 

not intended to be used as an absolute pass/fail for model performance. They are intended to 

be a general guide for interpreting such performance. These guidelines were developed from 

examining historical meteorological applications which were used for photochemical air 

quality studies. The majority of the model applications used 4 km horizontal grid spacing 

and fairly short time periods during which high ozone occurred in stagnant conditions.

It is also important to understand that the reported statistics are monthly average values and 

that at any hour the model may be over or underestimating the wind speeds. Furthermore, no 

model is able to capture the subtle features of the atmosphere. State-of-science 

meteorological modeling was conducted for the Liberty-Clairton PM2.5 SIP, and the 

evaluation of that state-of-science modeling was suggestive of where caution should be taken 

in interpreting the air quality modeling results.

Additionally, the modeling results are being used in a “relative” way. EPA recognizes 

limitations in modeling; thus, procedures developed by EPA to reduce limitations include the 

use of Relative Response Factors (RRFs) for attainment tests. So, in conformance with EPA’s 

recommended model attainment test, model results for the projected year (2014) were 

compared to results for the baseline year (2007). Therefore, model performance is 

acceptable for estimating future attainment. 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 93

36. Comment: The selection of the CAMx model over CMAQ is not justified. It should be noted that 

CMAQ is the EPA-developed model. It was used for PA SIPs for the 1997 NAAQS, including 

Liberty-Clairton, Pittsburgh-Beaver Valley, and Philadelphia-Wilmington. In non-attainment 

areas where both models have been used (e.g., Los Angeles and the South Coast Air Basin), 

CMAQ is the principal model while CAMx has been restricted to a supporting role, 

providing corroborating evidence to the CMAQ model predictions.

Commenter: Clean Air Council et al.

Response: There is no specific EPA-preferred model for photochemical modeling. CAMx 

was selected as the model for reasons specified in the Modeling Protocol (Appendix G-1), 

including local source treatment and two-way grid nesting features that are not available in 

the current version of CMAQ. CAMx has been used as the principal model for recent EPA 

modeling simulations such as CSAPR and for SIPs such as the South Coast Air Basin/Los 

Angeles 2007 Air Quality Management Plan.

37. Comment: The CAMx model is inaccurate due to severe underestimation of PM2.5 species and 

understates emissions controls. The tendency of underestimation invalidates the CAMx predictions 

and the attainment demonstration. Also, due to the underestimation of CAMx, CMAQ should be 

used as corroborative evidence or supplemental runs for the SIP.

Commenter: Clean Air Council et al.

Response: Both the CMAQ and CAMx models are sufficiently accurate for this type of 

demonstration. EPA recognizes limitations in the models; the purpose of procedures 

developed by EPA to use Relative Response Factors (RRFs) for the attainment tests is to 

minimize these limitations. (See also response to comment 35.)

Furthermore, as noted in EPA’s 2007 Modeling Guidance, “[b]y definition, models are 

simplistic approximations of complex phenomena” (EPA, 2007, pg. 98). This is especially 

true for PM where different measurement technologies can produce large differences in 

concentrations (e.g., different carbon measurement technologies can vary by 30%). For the 

Liberty-Clairton CAMx application, the model is achieving the PM Performance Criteria for 

all species but nitrate (as noted in the Table 7-8 of Appendix G-2). The CAMx nitrate 

underprediction occurs in the summer and warm months when observed and modeled nitrate 

concentrations are near zero because nitrate is a volatile chemical whose formation is favored 

under cooler temperatures. During the winter when nitrate concentrations are higher, CAMx 

performs much better and achieves the PM Performance Criteria (see Figure 7-19 in 

Appendix G-2). As noted in Figure 2-3 of Appendix G-2, ammonium nitrate is a small 

component of annual PM2.5 at Liberty (8%) and primarily occurs in the winter when CAMx 

achieves the PM Performance Criteria.

For projecting 2014 PM2.5 concentrations using the CAMx 2007 and 2014 modeling results, 

EPA’s Modeling Guidance was followed using the Speciated Modeled Attainment Test 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 94

(SMAT), which utilizes the modeling results in a relative sense to scale the observed current 

year PM2.5 species concentrations to project 2014 future year PM2.5 concentrations. EPA 

recommends using the relative changes in the modeling results between 2007 and 2014 

because it roots the PM projections in the observations and reduces uncertainties; for 

example, if the model is underestimating the 2007 PM2.5 species, it is also likely 

underestimating the 2014 PM2.5 species concentrations. So, by taking their ratio to scale the 

observed PM2.5 species concentration, the underestimation cancels out in the 2014 projection 

procedure. Thus, a CAMx underestimation or overestimation bias does not mean that it 

underestimates or overestimates the effects of the changes in emissions between 2007 and 

2014 on PM concentrations since the modeling results are used in a relative fashion as 

recommended by EPA.

38. Comment: Nearby receptors for primary PM2.5 modeling are too coarse to capture maximum 

concentrations from local sources. To capture maximum concentrations, receptors should be 

spaced at 25 m or less, without averaging the receptors.

Commenter: Clean Air Council et al.

Response: The nearby receptors were chosen to represent the FRM sites within a perimeter 

of similar terrain, and there are no sources that were not accounted for within the 100 m 

spacing. This receptor methodology uses a much finer scale than that prescribed by the EPA 

Modeling Guidance, which recommends averaging the concentrations across a 7 x 7 array of 

grid cells centered on the monitor.

39. Comment: The CAMx model is invalid for predicting primary PM2.5 concentrations from large 

point sources within a fine grid at 0.8 km spacing. The submodel PiG in CAMx has not been 

approved by EPA; AERMOD should have been used for the modeling of local primary PM2.5. 

Additionally, Liberty meteorology was not used for the AERMOD comparison given in Appendix 

G-3.

Commenter: Clean Air Council et al.

Response: The choice of CAMx was reviewed with EPA Region III during the development 

of the Modeling Protocol. CAMx was one of several models recommended by the EPA to 

predict fine particulate matter concentrations in nonattainment areas. Section 13.1 in EPA’s 

2007 Modeling Guidance document notes that “a State may use a regional photochemical 

grid model to address both primary and secondary components of particulate matter ....” 

The plume-in-grid modeling option incorporates a puff/plume model within a larger-scale 

grid model such as CAMx, to account for significant individual emission sources in an area 

of interest. According to Karamchandani, P., Vijayaraghavan, K., and Yarwood, G. (2011) 

in an article titled “Sub-grid scale plume modeling” in the journal Atmosphere (vol. 2, pages 

389-406), “[t]he embedded model tracks the sub-grid scale process (e.g., elevated point 

source emissions) until the fine scale variability becomes unimportant (referred to as the 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 95

‘puff dumping’ or ‘hand-over’ point), at which point the grid model takes over the 

calculations for that process while the embedded model continues tracking sub-grid scale 

processes” (pg. 394). Karamchandani, et al., 2011, go on to say that a plume “is represented 

by a myriad of three-dimensional puffs that are advected and dispersed according to the local 

micrometeorological characteristics.... Also, the effects of buoyancy on plume rise and 

initial dispersion are simulated by solving the conservation equations for mass, heat, and 

momentum.” Furthermore, “[c]hemical species concentrations in the puffs are treated as 

perturbations from the background concentrations” (pg. 395).

Lastly, the comparison to AERMOD in Appendix G-3 used Liberty meteorological data for 

the AERMOD simulation, with PIT airport data used only for substitution during missing 

periods. CAMx with PiG estimated concentrations as well as or better than CAMx with 

AERMOD.

40. Comment: The CAMx model is invalid for predicting secondary PM2.5 concentrations from large 

point sources within a fine grid at 0.8 km spacing. The CAMx model uses eddy diffusion 

coefficients for treating turbulent diffusion in the atmosphere. This K-theory approximation is 

known to be invalid near large point sources.

Commenter: Clean Air Council et al.

Response: The use of the K-theory approximation was appropriate for this modeling situation. The 

commenter’s K-theory statement is likely based on pages 885 through 889 in Seinfeld, J.H., and 

Pandis, S.N. (1998), Atmospheric Chemistry and Physics: From Air Pollution to Climate Change

(New York: John Wiley & Sons). In particular, page 889 states that a key equation that describes 

statistical properties of concentrations “is a valid description of turbulent diffusion and chemical 

reaction as long as [specified basic restrictions] hold, namely, that the reaction processes are slow 

compared with turbulent transport and the characteristic lengthscale and timescale for changes in the 

mean concentration field are large compared with the corresponding scales for turbulent transport. 

Because the eddy timescale...and the lengthscale...are often quite large in the atmosphere, the above 

conditions are violated near strong isolated sources.”

However, the discussion on page 889 continues with “...to satisfy the condition that the characteristic 

lengthscale of the concentration field be much greater than that of the turbulence, the spatial scale for 

variations in [concentration]... must be of the order of 100 to 1000 m. In addition, under these 

conditions the timescale of the fastest reactions must be no smaller than on the order of about 10 min. 

The conclusion we draw at this point is that [the key equation] is a valid model provided it is applied 

to situations in which chemical reactions are ‘slow’ and the distribution of sources is ‘smooth’” 

(emphasis in original). The source-receptor situation in the nonattainment area and the way the 

situation was modeled satisfy these two criteria.

41. Comment: The SIP states on Page 21 (also in the Modeling Protocol, Appendix G-1) that CB6 

chemical mechanism represents the latest understating of photochemistry. This must be a 

typographical error, which should read “understanding” of photochemistry.

Commenter: Clean Air Council et al.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 96

Response: The SIP and Appendix G-1 have been corrected accordingly.

42. Comment: CAMx predictions may be misleading since its 25 vertical layers are collapsed from 

the 37 WRF layers. The CMAQ Operational Guidance Document states that layer collapsing is 

“not recommended, as dynamical inconsistencies can develop and lead to misleading results.”

Commenter: Clean Air Council et al.

Response: Most CAMx applications use layer collapsing to reduce the number of vertical 

layers in CAMx for computational efficiency. For the Liberty-Clairton SIP modeling, a no 

layer collapsing sensitivity test was performed and found essentially identical modeling 

results whether layer collapsing was used or not (see Appendix G-3). Note that the Denver 

ozone SIP also used a similar layer collapsing scheme to reduce the 37 vertical layers in 

WRF to 25 in CAMx and also conducted a no layer collapsing sensitivity test and found 

essentially identical results. Thus, there do not appear to be any inconsistencies whether 

layer collapsing is used or not. EPA’s recommendations for running CMAQ are not relevant 

to CAMx.

43. Comment: CAMx uses boundary conditions derived from the predictions of the global MOZART 

model without justification. In the CSAPR modeling, EPA used boundary conditions derived from 

the GEOS-Chem model. The selection of MOZART over GEOS-Chem should be documented.

Commenter: Clean Air Council et al.

Response: At the time that the CAMx model inputs were developed, 2007 global chemistry 

model output was readily available for only the MOZART global chemistry model. 

Furthermore, MOZART model produces comparable results to other global chemical 

transport models. MOZART provides sufficient horizontal resolution to simulate chemical 

transport on synoptic weather scales and sufficient vertical resolution to simulate mass 

exchange between the upper- and surface-layer atmospheres.

44. Comment: CAMx sensitivity to key modeling inputs such as initial conditions, boundary 

conditions, and emissions has not been analyzed. 

Commenter: Clean Air Council et al.

Response: The sensitivity of the model to local emissions sources was extensively analyzed 

using the Plume-in-Grid module and PM Source Apportionment Technology (PSAT) probing 

tool. The modeled local source contribution to annual PM2.5 concentrations at Liberty was 

compared to an estimate based on analysis of observations. Overall model performance was 

evaluated and found satisfactory.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 97

45. Comment: The ACHD staff is to be commended for conducting some of the most 

sophisticated localized modeling ever performed. The modeling projects that the area will be 

in attainment with both the 2006 daily and 2012 annual PM2.5 standards.

Commenter: Greater Pittsburgh Chamber of Commerce.

Response: ACHD staff appreciates the comment.

ATTAINMENT TESTS

Comments related to the assumptions and methodology used for the design value 

calculations.

46. Comment: ACHD should consider the use of significant figures in the calculations shown in 

Sections 6.4 and 6.5. 

Commenter: U.S. EPA Region III.

Response: The data shown for the attainment test calculations were rounded to a precision 

of three decimal places for all intermediate calculations. For better comparison to the 

NAAQS, the final design values will be revised in the tables to show the values according to 

rounding conventions given in 40 CFR Part 50 Appendix N, with the annual design values 

rounded to the nearest tenth and the 24-hour rounded to the nearest whole number.

47. Comment: Liberty speciation data was used to represent both Liberty and Clairton in the 

attainment tests. This assumption is not accurately or adequately supported by the information 

given in the SIP.

Commenter: U. S. Steel Corporation.

Response: With no other speciation data available, the Liberty speciation data is used to 

represent species composition throughout the area. This follows the EPA Modeling 

Guidance methodology to use the nearest speciation site when no other data is available. The 

SANDWICH technique used for the attainment tests adjusts the species fractions to the FRM 

data measured at the Clairton site. 

48. Comment: Tables 6-5 through 6-8 show projected data for the weighted timeframe of 2005-2009, 

which does not coincide with the monitored data.

Commenter: Clean Air Council et al.

Response: ACHD apologizes for the confusion in these tables. The years shown are based 

on the recalculation of the 2005-2009 24-hour design values using the modeled reductions, 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 98

according to the EPA attainment test methodology. The tables have been revised to show 

“Year 1, Year 2,” and so on.

RACT/RACM

Comments related to the RACT/RACM analysis in the SIP.

49. Comment: The SIP states that the Clairton Plant coke batteries have some of the nation’s strictest 

standards. As part of the RACT/RACM analysis, a more specific explanation should be provided 

of which standards apply to these units in order for EPA to determine if they meet RACT/RACM 

requirements.

Commenter: U.S. EPA Region III.

Response: A detailed list of controls by process for the U. S. Steel Clairton Plant has been 

provided in Appendix I. The RACT/RACM section of the SIP has been revised for 

clarification.

CONTINGENCY MEASURES

Comments related to the additional contingency controls used in case the plan fails to 

demonstrate attainment by the attainment date.

50. Comment: It is inappropriate that U. S. Steel’s Clairton Plant is the only source required to reduce 

emissions should attainment not be met. Such an approach is inequitable and unreasonable 

considering that significant sources of PM2.5 and precursors upwind of the Liberty-Clairton area 

would not be obligated to reduce emissions. If CSAPR is not enforceable due to the vacatur, U. S. 

Steel may be forced to implement contingency measures based on poor background or regional air 

quality. The language in Section 8 should be revised to allow for the cause of nonattainment to be 

evaluated prior to the contingency measures taking effect.

Commenter: U. S. Steel Corporation.

Response: ACHD recognizes that both local and regional sources impact the LibertyClairton area and will continue to analyze air quality contributions in the future. For the 

purposes of this SIP, the contingency measures are appropriate considering the control 

strategy and supporting analyses. Continuous monitored data shows that exceedances of the 

24-hour PM2.5 standard are driven by short-term peak levels occurring during inversion 

periods. These peak levels can occur in all seasons and can be independent of regional air 

quality. The most significant local source factors from the PMF analysis (Appendix C-2) are 

industrial carbons, influenced strongly by inversions, with the highest contributions from the 

southwest of the Liberty monitor. While other source factors are evident and can lead to both 

long-term and short-term impacts, exceedance levels can be most attributed to local industrial 

carbons sources.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 99

51. Comment: The SIP represents a step forward in the continued improvement of our region’s 

air quality. However, continued attention is needed to ensure future environmental 

regulations do not disproportionately impact economic development and that the burden of 

emissions reductions is not unfairly shouldered by select industries or organizations. The 

contingency plan’s only course of action should the area fail to come into attainment is to 

wrest further reductions from the U. S. Steel Clairton facility. But, many emission sources, 

including alternative home heating sources, out-of-region transport, and vehicle traffic 

contribute to the area’s pollutants.

Commenter: Greater Pittsburgh Chamber of Commerce.

Response: See response to previous comment. A contingency measure is not necessarily a 

remedy to a nonattainment situation but rather a starting point that allows for reductions to 

take place while a new overall plan is developed.

WEIGHT OF EVIDENCE

Comments related to the supporting evidence used to show that the Liberty-Clairton 

area shows decreasing trends of PM2.5.

52. Comment: ACHD should address if a switch to natural gas for diesel-burning equipment is 

foreseeable, and if this shift would affect local/regional PM2.5.

Commenter: U.S. EPA Region III.

Response: Any switches to natural gas from diesel would lower the carbon contributions 

from stationary or mobile sources. Possible increases in NOx from increased natural gas 

usage would not likely affect PM2.5 concentrations in the Liberty-Clairton area, as nitrates 

make up only a small portion of the localized excess at Liberty. Additionally, regional 

increases of upwind NOx due to shale gas production in the future modeled case showed little 

apparent effect on the future case PM2.5 impacts in Liberty-Clairton.

53. Comment: The SIP should mention the potential benefits associated with the EPA Boiler MACT 

rules promulgated on January 13, 2013.

Commenter: U. S. Steel Corporation.

Response: The Boiler MACT and other federal MACT rules were included as on-the-book 

controls in the MANE-VU inventories. The weight of evidence section focused on rules or 

other supporting factors that were not included in the modeling inventories.

54. Comment: The SIP mentions wood stoves and wood-fired boilers regulations that provide 

particulate reductions, but U. S. Steel is concerned with the difficulty in locating these sources and 
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 100

proper enforcement of the regulations. U. S. Steel is also concerned about the ability to enforce 

anti-idling regulations.

Commenter: U. S. Steel Corporation.

Response: ACHD maintains an enforcement staff that includes full-time field inspectors that 

investigate potential air quality violations in response to complaints or based on personal 

observations. Local law enforcement and PA DEP enforce idling regulations in the state of 

PA.

Furthermore, the wood stove and outdoor wood-fired boilers programs result in the 

manufacturing and sales of cleaner-burning units, independent of the location of units. To 

address wood-burning units not covered by these programs, ACHD has implemented an 

emission mitigating “clean-burning” educational campaign to proactively reduce wood 

smoke emissions.

55. Comment: Emissions reduction measures listed in the weight of evidence section may be relied 

upon only if they are federally enforceable.

Commenter: Clean Air Council et al.

Response: The weight of evidence section is based on qualitative evidence that the LibertyClairton area will incur reductions that were not incorporated in the modeling demonstration. 

This can include population trends, local programs, and other factors that lead to reductions 

that were not included in the control strategy or quantified in the modeled inventories. These 

factors need not be federally enforceable.

56. Comment: Section 9.7 regarding the monitored data during low productions periods should be 

examined by individual year, correlating changes in emission rates with monitored data. 

Additionally, subtracting Lawrenceville averages from Liberty may not be a valid technique for 

examining local vs. regional trends.

Commenter: Clean Air Council et al.

Response: The monitored data during low production was provided as weight of evidence to 

show that low production levels yielded real-world changes in monitored data, similar to the 

expected modeling reductions. Individual years were not examined as year 2009 experienced 

much lower levels of production than in previous years. However, air quality has continued 

to improve after 2009. Additionally, the Lawrenceville site was used to represent regional 

PM2.5 concentrations since it is the only other continuous PM2.5 site in Allegheny County.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 101

Notes on commenters:

 U.S. EPA Region III comments were submitted by Diana Esher, Director, Air Protection 

Division, U.S. EPA Region III.

 Greater Pittsburgh Chamber of Commerce comments were submitted by Barbara 

McNees, President, Greater Pittsburgh Chamber of Commerce.

 U. S. Steel Corporation comments were submitted by Coleen M. Davis, Senior 

Environmental Engineer, U. S. Steel.

 Clean Water Action comments were submitted by Tom Hoffman, Western Pennsylvania 

Director, Clean Water Action.

 Clean Air Council et al. comments were collaborative comments from Clean Air Council 

(Council), Citizens for Pennsylvania’s Future (PennFuture), Group Against Smog and 

Pollution (GASP), Clean Water Action, Sustainable Pittsburgh, Sierra Club, Residents for 

a Clean and Healthy (REACH) Mon Valley, and Center for Coalfield Justice, 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

o Joe Osborne, Esq., Legal Director, Group Against Smog and Pollution

o Court Gould, Executive Director, Sustainable Pittsburgh

o Randy Francisco, Pennsylvania Organizing Representative, Sierra Club

o REACH Mon Valley

o Joanne Kilgour, Esq., Legal Director, Center for Coalfield Justice

Contributors to these comments also included the following:

o Khanh Tran, Principal, AMI Environmental, on behalf of Clean Air Council 

o William Charlton, on behalf of Citizens for Pennsylvania’s Future
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 102

11.5 Certification of Adoption
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 103

References

Abt Associates Inc. (2012). Modeled Attainment Test Software User’s Manual. Prepared for 

U.S. EPA, Office of Air Quality Planning and Standards. Available at: 

http://www.epa.gov/ttn/scram/guidance/guide/MATS-2-5-1_manual.pdf

Allegheny County Health Department (ACHD) (2012). PM2.5 Modeling Protocol, 2006 PM2.5

Standards, Liberty-Clairton Nonattainment Area. Air Quality Program.

Allegheny County Health Department (ACHD) (2008). Installation Permit 0052-I011 for U. 

S. Steel C Battery.

Allegheny County Health Department (ACHD) (2011). Installation Permit 0052-I014 for U. 

S. Steel Quench Towers 5A and 7A.

ASTM International (2010). Standard D6589-05, “Standard Guide for Statistical Evaluation of 

Atmospheric Dispersion Model Performance,” Annual Book of ASTM Standards, Section 11, “Water 

and Environmental Technology,” Volume 11.07, “Atmospheric Analysis.”

Desert Research Institute (2005). Source Apportionment Analysis of Air Quality Monitoring 

Data: Phase II. Prepared for the Mid-Atlantic/Northeast Visibility Union and Midwest Regional 

Planning Organization. Available at: 

http://www.ladco.org/reports/rpo/data_analysis/source_apportionment_study_of_improve_data_p

hase_ii_draft_final_report_dri.pdf

ENSR Corporation (2008). Installation Permit Application for the Proposed C Battery 

Project. Prepared for United States Steel Corporation.

ENVIRON International Corporation (2011). User’s Guide, Comprehensive Air quality Model 

with extensions, Version 5.40. CAMx model. Available at: 

http://www.camx.com/files/camxusersguide_v5-40.aspx

Fox, T. (2011). “Update to the 24-Hour PM2.5 NAAQS Modeled Attainment Test.” 

Memorandum. U.S. EPA, Office of Air Quality Planning and Standards. June 28. Available at: 

http://www.epa.gov/scram001/guidance/guide/Update_to_the_24-

hour_PM25_Modeled_Attainment_Test.pdf

Karamchandani, P., Vijayaraghavan, K., & Yarwood, G. Sub-grid scale plume modeling. 

Atmosphere. 2, 389-406. 2011. Available at: http://www.mdpi.com/2073-4433/2/3/389

McNally, D. & Loomis, C. (2012). Application and Evaluation of WRF for Calendar Year 2007. 

Prepared for Allegheny County Health Department by Alpine Geophysics, LLC.

Northeast States for Coordinated Air-Use Management (NESCAUM) (2006). The Nature of the 

Fine Particle and Regional Haze Air Quality Problems in the MANE-VU Region: A Conceptual 

Description. Available at: http://www.nescaum.org/topics/regional-haze/regional-hazedocuments
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 104

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

Robinson, A. L., Khlystov, A., Wittig, B., Davidson, C. I., & Pandis, S. N. (2003).

Characteristics and Sources of PM2.5 in the Pittsburgh Region., Carnegie Mellon University. 

Available at: http://www.netl.doe.gov/publications/proceedings/02/air_q3/CMU.pdf

Sullivan Environmental Consulting, Inc. (2007). The Processing of CALMET Files for 

Allegheny County’s PM2.5 SIP Analysis. Prepared for Allegheny County Health Dept.

Sullivan Environmental Consulting, Inc. (1996). Review of Meteorology at the Clairton Area: 

Strengthening Dispersion Modeling for State Implementation Plans. Prepared for Allegheny 

County Health Dept.

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 (2011). Air Quality Modeling: Final Rule Technical Support Document [for the 

Transport Rule (CSAPR)]. Available at: http://www.epa.gov/airtransport/pdfs/AQModeling.pdf

U.S. EPA (2011). Update to the 24 Hour PM2.5 NAAQS Modeled Attainment Test. Available at: 

http://www.epa.gov/scram001/guidance/guide/Update_to_the_24-

hour_PM25_Modeled_Attainment_Test.pdf

U.S. EPA (2007). Guidance on the Use of Models and Other Analyses for Demonstrating 

Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze. EPA-454/B-07-002. 

Available at: http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf

U.S. EPA (2006). Definition of SANDWICHed STN Data. Available on EPA’s Air Explorer 

web page: www.epa.gov/mxplorer/sandwich_description.doc

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 (2012). Updated R Analysis for the Liberty-Clairton PM-2.5 

Nonattainment Area. Air Quality Analysis Branch.
Liberty-Clairton PM2.5 SIP Revision, 2006 Stds. May 10, 2013 Page 105

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