Revision to the

Allegheny County Portion of the 

Pennsylvania State Implementation Plan

Attainment Demonstration for the

Liberty-Clairton

PM2.5 Nonattainment Area

Allegheny County Health Department

Air Quality Program

April 2011
Liberty-Clairton PM2.5 SIP Revision April 2011 Page - 2 -

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Liberty-Clairton PM2.5 SIP Revision April 2011 Page i

Table of Contents

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

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

List of Appendices......................................................................................................................... vi

Acronyms and Abbreviations ....................................................................................................... vii

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

2. Regulation Changes................................................................................................................... 4

3. Problem Statement..................................................................................................................... 5

3.1. Introduction......................................................................................................................... 5

3.2. Monitoring .......................................................................................................................... 9

3.3. Data Analysis.................................................................................................................... 10

3.3.1. Regional, Urban, and Local Concentrations.............................................................. 10

3.3.2. Speciation of PM2.5 Data............................................................................................ 12

4. Control Strategy....................................................................................................................... 13

5. Explanation of Proposed Attainment Date .............................................................................. 17

6. Emissions Inventory................................................................................................................. 18

7. Modeling Procedures............................................................................................................... 21

7.1. Design ............................................................................................................................... 21

7.1.1. Protocol...................................................................................................................... 21

7.1.2. Years Modeled ........................................................................................................... 23

7.2. Methodology..................................................................................................................... 24

7.2.1. Sources Modeled........................................................................................................ 24

7.2.2. Combination of Impacts............................................................................................. 24

7.2.3. Reconstruction of Species.......................................................................................... 25

7.2.4. Modeled Source Groups............................................................................................. 26

7.2.5. Emissions Totals........................................................................................................ 32

7.2.6. Combination of Impacts............................................................................................. 32

7.2.7. Aggregation of Source Groups and Domains............................................................ 33

7.2.8. Combination of Annual Impacts................................................................................ 33

7.2.9. Combination of 24-Hour Impacts.............................................................................. 34

8. Attainment Demonstration....................................................................................................... 35

8.1. Monitored Data Assumptions........................................................................................... 35

8.2. Annual Attainment Test Methodology ............................................................................. 35

8.3. 24-Hour Attainment Test Methodology............................................................................ 37

8.4. Annual Standard Test Results........................................................................................... 38

8.5. 24-Hour Standard (65 μg/m3) Test Results....................................................................... 41

8.6. Lincoln Area Analysis ...................................................................................................... 43

8.7. Model Performance........................................................................................................... 48

9. Reasonably Available Control Technology and Measures...................................................... 58

10. Reasonable Further Progress.................................................................................................. 61

10.1. Reasonable Further Progress Requirements ................................................................... 61

10.2. Reasonable Further Progress Calculations...................................................................... 62
Liberty-Clairton PM2.5 SIP Revision April 2011 Page ii

11. Contingency Measures........................................................................................................... 65

11.1. Indentified Contingency Measures to be Implemented .................................................. 65

11.2. Contingency Measures – SO2 and NOx .......................................................................... 66

11.3. Additional Contingency Measures.................................................................................. 67

12. Transportation Conformity .................................................................................................... 68

13. Weight of Evidence................................................................................................................ 71

13.1. Local and Regional Trends............................................................................................. 71

13.2. Wood Stoves & Wood-Fired Boilers.............................................................................. 74

13.3. National Regulations – CAIR and TR ............................................................................ 74

13.4. Diesel Campaign............................................................................................................. 76

13.5. State and Competitive ARRA Clean Diesel Grants........................................................ 77

13.6. Population Trends........................................................................................................... 78

13.7. Monitored Data During Low Production........................................................................ 80

14. Emergency Episodes.............................................................................................................. 85

15. Legal Documents................................................................................................................... 86

15.1. Notice of Public Hearing and Comment Period ............................................................. 86

15.2. Transmittals of Hearing Notice to PA DEP and EPA..................................................... 87

15.3. Proof of Publication and Certification of Public Hearing............................................... 90

15.4. Summary of Public Comments and Responses .............................................................. 92

15.5. Certifications of Approval and Adoption ..................................................................... 104

References................................................................................................................................... 109
Liberty-Clairton PM2.5 SIP Revision April 2011 Page iii

LIST OF TABLES

Table 3-1: Comparison of 2002 Liberty and Lawrenceville PM2.5 Concentrations on NonInversion Days................................................................................................................9

Table 6-1: Baseline 2002 Emissions (Tons/Year) .............................................................................20

Table 6-2: Future Projected 2014 Emissions (Tons/Year) ................................................................20

Table 7-1: Modeled Emissions Totals ...............................................................................................32

Table 8-1: Baseline Quarterly Compositions – Liberty Annual ........................................................39

Table 8-2: Modeled Relative Response Factors (RRFs) – Liberty Annual.......................................39

Table 8-3: Future Projected Quarterly Compositions – Liberty Annual ...........................................39

Table 8-4: Liberty Annual Design Values.........................................................................................39

Table 8-5: Baseline Quarterly Compositions – Clairton Annual.......................................................40

Table 8-6: Modeled Relative Response Factors (RRFs) – Clairton Annual......................................40

Table 8-7: Future Projected Quarterly Compositions – Clairton Annual..........................................40

Table 8-8: Clairton Annual Design Values........................................................................................40

Table 8-9: Baseline Quarterly High Days – Liberty 24-Hour ...........................................................41

Table 8-10: Baseline Quarterly Compositions – Liberty 24-Hour ....................................................41

Table 8-11: Modeled Relative Response Factors (RRFs) – Liberty 24-Hour ...................................41

Table 8-12: Future Projected Quarterly High Days – Liberty 24-Hour.............................................41

Table 8-13: Liberty 24-Hour Design Values.....................................................................................41

Table 8-14: Baseline Quarterly High Days – Clairton 24-Hour........................................................42

Table 8-15: Baseline Quarterly Compositions – Liberty 24-Hour (by percentage, applied to 

Clairton high days).........................................................................................................42

Table 8-16: Modeled Relative Response Factors (RRFs) – Clairton 24-Hour..................................42

Table 8-17: Future Projected Quarterly High Days – Clairton 24-Hour ...........................................42

Table 8-18: Clairton 24-Hour Design Values....................................................................................42

Table 8-19: Future Case Design Values ............................................................................................43

Table 8-20: Statistics for the Modeled Daily Liberty Averages Compared to the Liberty FRM 

Values, Year-Round and by Season, 2002 .....................................................................53

Table 8-21: Statistics for the Modeled Hourly Liberty Values Compared to the Liberty TEOM 

Values, Year-Round and by Season, 2002 .....................................................................57

Table 10-1: Emissions Inventory Adjusted for Plan Control Strategy (in Tons per Year)................62

Table 10-2: Determining Benchmark Milestones as Tons per Year of Reductions ..........................62

Table 10-3: Comparison of 2009 and 2012 RFP Benchmarks and Projected Levels........................63

Table 10-4: Fraction of Reductions Achieved in Each Milestone Year ............................................63

Table 11-1: Calculation of Required and Excess Emission Reductions............................................65

Table 11-2: Contingency Measures Emission Reductions ................................................................66

Table 12-1: Annual Motor Vehicle Emission Budgets (Tons/Year) .................................................69

Table 12-2: Daily Motor Vehicle Emission Budgets (Tons/Day) .....................................................69

Table 13-1: Future Case CAIR and TR Emissions............................................................................75

Table 13-2: EGU Control Implementation Schedule and Progress...................................................76

Table 13-3: PM2.5 FRM Quarterly Averages, 2005-2008 and 2009..................................................83
Liberty-Clairton PM2.5 SIP Revision April 2011 Page iv

LIST OF FIGURES

Figure 3-1: Map of the Liberty-Clairton Area within the Pittsburgh-Beaver Valley Area ...............6

Figure 3-2: Daily PM2.5 Concentrations During the 2002 Base Year, Comparing Multiple 

Allegheny County Monitors...........................................................................................7

Figure 3-3: 2002 Base Year Days with PM2.5 Concentrations Higher than 50 μg/m3 at the Liberty 

Monitor and Days with Inversions Greater than 3oC .....................................................8

Figure 3-4: PM2.5 Annual Design Values Since 2000 .......................................................................10

Figure 3-5: Regional, Urban, and Local PM2.5 Concentrations.........................................................11

Figure 3-6: Localized Excess at Liberty ............................................................................................12

Figure 7-1: Modeling Domains..........................................................................................................22

Figure 7-2: Modeling Domains by Land Use and Terrain.................................................................23

Figure 7-3: Combination of Modeled Impacts for Total Carbons.....................................................25

Figure 7-4: Map of Modeled Sources Outside Allegheny County (no EGUs)..................................27

Figure 7-5: Map of Modeled EGUs...................................................................................................28

Figure 7-6: Map of Allegheny County Source Groups and 20 km Domain......................................29

Figure 7-7: Map of Modeled 20 km Domain Sources/Groups..........................................................30

Figure 7-8: Map of Near-Field Sources with Building Parameters...................................................31

Figure 8-1: Receptor Grid for the Lincoln Area ................................................................................44

Figure 8-2: Annual Impacts by Percent Reduction in Lincoln Area .................................................45

Figure 8-3: Annual Percent Reductions with Descriptions................................................................46

Figure 8-4: 24-Hour Impacts by Percent Reduction in Lincoln Area................................................47

Figure 8-5: Hourly Average Liberty Modeled and Monitored PM2.5 (TEOM), Baseline 2002, 

Year-Round Basis...........................................................................................................48

Figure 8-6: Hourly Average Liberty Modeled and Monitored PM2.5 (TEOM), Baseline 2002, 

Quarterly Basis...............................................................................................................49

Figure 8-7: Hourly Average Liberty Modeled Baseline and Future Cases, 2002 and 2014, YearRound Basis....................................................................................................................50

Figure 8-8: Hourly Average Liberty Modeled Baseline and Future Cases, 2002 and 2014, 

Quarterly Basis...............................................................................................................51

Figure 8-9: Daily Average Liberty Modeled and Monitored (FRM), Baseline 2002........................52

Figure 8-10: Liberty Daily Model Statistics, Baseline 2002 .............................................................54

Figure 8-11: Liberty Modeled and Monitored Correlation, Daily Averages, Baseline Case 2002, 

Year-Round Basis.........................................................................................................55

Figure 8-12: Liberty Modeled and Monitored Correlation, Daily Averages, Baseline Case 2002, 

Quarterly Basis..............................................................................................................56

Figure 12-1: Conformity Assessment for the Liberty-Clairton Area, Annual PM2.5.........................70

Figure 12-2: Conformity Assessment for the Liberty-Clairton Area, Daily PM2.5............................70

Figure 13-1: PM2.5 FRM Annual Averages in Allegheny County, 2000-2009 .................................71

Figure 13-2: PM2.5 FRM 3-Year Averages in Allegheny County, 2000-2009..................................72

Figure 13-3: Liberty and Clairton Annual Design Values with Trend Lines....................................73

Figure 13-4: Population Trends for Allegheny County, 1990-2000..................................................79

Figure 13-5: Long-Term Hourly PM2.5 TEOM Averages at Liberty and Lawrenceville, 2000-

2008...............................................................................................................................80

Figure 13-6: Hourly 2009 PM2.5 TEOM Averages at Liberty Compared to Long-Term 2000-2008

Averages .......................................................................................................................81
Liberty-Clairton PM2.5 SIP Revision April 2011 Page v

Figure 13-7: Hourly 2009 PM2.5 TEOM Averages at Lawrenceville Compared to Long-Term 

2000-2008 Averages.....................................................................................................82

Figure 13-8: Hourly 2009 PM2.5 TEOM Average Differences Between Liberty and 

Lawrenceville Compared to Long-Term 2000-2008 Data............................................84
Liberty-Clairton PM2.5 SIP Revision April 2011 Page vi

LIST OF APPENDICES

Appendix A: Monitored Data and Inversion Analysis

Appendix B: RACT Analysis by Source

Appendix C: Model Protocol for Liberty-Clairton Modeling

Appendix D: Meteorological Evaluation of Liberty-Clairton Area

Appendix E: ACHD PM2.5 Speciation and PMF Analyses

Appendix F: Liberty-Clairton Emissions Inventories

F-1: Stationary Point Sources

F-2: Area Sources

F-3: Nonroad Sources

F-4: Mobile Sources

Appendix G: MANE-VU Inventory and Projection Documentation

G-1: TSD for 2002 MANE-VU SIP Modeling

G-2: Development of Emission Projections

G-3: Emissions Processing for 2002 OTC

G-4: Future Year Emissions Inventory for OTC

Appendix H: Modeling and Reasonable Further Progress (RFP) Inventories

H-1: Inventory Revisions

H-2: Inventory Listings

Appendix I: Dispersion Model Files and Supporting Documentation

I-1: 20km Modeled Source Groups

I-2: 150km Modeled Source Groups

I-3: CALMET Settings

I-4: CALMET Differences from FLM

I-5: CALPUFF Settings

I-6: Battery Flow Rates and Plume Rise Treatment

Appendix J: Attainment Demonstration

J-1: Annual Standard Attainment Test

J-2: 24-Hour Standard Attainment Test

J-3: Impact Tables

Appendix K: CMAQ Modeling Documentation

K-1: CMAQ Model Performance and Assessment

K-2: Meterological Modeling using MM5

K-3: Processing of 2002 Anthropogenic Emissions

K-4: PM2.5 Modeling using SMOKE/CMAQ
Liberty-Clairton PM2.5 SIP Revision April 2011 Page vii

ACRONYMS AND ABBREVIATIONS

ACHD Allegheny County Health Department

AQS Air Quality System (EPA)

BACT Best Available Control Technology

CAA Clean Air Act

CAIR Clean Air Interstate Rule

CALPUFF California Puff Dispersion Model

CALMET California Meterological Processor (with CALPUFF)

CFR Code of Federal Regulations

CMAQ Community Multiscale Air Quality Model

DON Degree of Neutralization

EC Elemental Carbon

EGU Electric Generating Unit

EPA The United States Environmental Protection Agency

FMVCP Federal Motor Vehicle Control Program

FLM Federal Land Managers

FR Federal Register

FRM Federal Reference Method Monitor

MANE-VU Mid-Atlantic/Northeast Visibility Union

MARAMA Mid-Atlantic Regional Air Management Association

MATS Modeled Attainment Test Software

MM5 Mesoscale Model Version 5

MSA Metropolitan Statistical Area

NAAQS National Ambient Air Quality Standard

NEI EPA National Emission Inventory Database

NLCD National Land Cover Data

NYSDEC New York State Department of Environmental Conservation

NOx Oxides of Nitrogen

OC Organic Carbon

OCMmb Organic Carbonaceous Mass by Mass Balance

OTB/W On-The-Books/On-The-Way Regional Controls

PA DEP Pennsylvania Department of Environmental Protection

PBW Particle Bound Water 

PIT Pittsburgh International Airport

PM Airborne Particulate Matter of any size

PM2.5 Particulate Matter less than 2.5 microns in diameter, or Fine Particulates 

PM10 Particulate Matter less than 10 microns in diameter

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
Liberty-Clairton PM2.5 SIP Revision April 2011 Page viii

SIP State Implementation Plan

SMAT Speciated Modeled Attainment Test

SMOKE Sparse Matrix Operator Kernel Emissions System

SO2 Sulfur Dioxide

STN Speciation Trends Network

TR Transport Rule

TEOM Tapered Element Oscillating Microbalance Monitor

Tons/year Tons per year of pollutant emissions

TSD Technical Support Document

USGS United States Geological Survey

μg/m3 Microgram per cubic meter

μm Micrometer

VMT Vehicle Miles Traveled

VOC Volatile Organic Compound
Liberty-Clairton PM2.5 SIP Revision April 2011 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) in diameter, 

approximately 1/30

th 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.

The United States Environmental Protection Agency (EPA) published air quality designations 

for the PM2.5 standard based on air quality monitoring data from 2001-2003 in the Federal 

Register on January 5, 2005 (70 FR 944), effective on April 5, 2005. Included in the 

designations were the Pittsburgh-Beaver Valley PM2.5 nonattainment area and, within that area, a 

Liberty-Clairton PM2.5 nonattainment area. This SIP is an attainment demonstration of the 

Liberty-Clairton area.

This SIP is a control strategy and attainment demonstration of the 1997 federal ambient 

standards of 15 μg/m3 annual average and 65 μg/m3 24-hour average PM2.5. More recently new 

standards were issued, of 15 μg/m3annual average and 35 μg/m324-hour average PM2.5. If 

necessary, a separate SIP submittal will be made to demonstrate attainment of these newer 

standards at a later date. However, the SIP included here adds these new annual PM2.5 standard

of 15 μg/m3and the hourly standard of 35 μg/m3to the list of standards in ACHD Article XXI 

§2101.10, since these are the standards at the present time.

The Pittsburgh-Beaver Valley nonattainment area is located in southwestern Pennsylvania and 

consists of Beaver, Butler, Washington, and Westmoreland counties and portions of Allegheny, 

Armstrong, Greene and Lawrence counties. Located within the Pittsburgh-Beaver Valley Area is 

a separate nonattainment area entirely in southeastern Allegheny County. This is known as the 

Liberty-Clairton nonattainment area, and comprises the boroughs of Glassport, Liberty, Lincoln, 

Port Vue, and the city of Clairton. The Liberty-Clairton PM2.5 nonattainment area was 

designated as a separate, distinctively local-source impacted, nonattainment area because the 

combination of emissions from the local sources in a narrow river valley creates a local air 

quality problem uniquely different from the remainder of the Pittsburgh-Beaver Valley area.

At the time of designation, the Liberty-Clairton annual design value was 21.2 μg/m3, based on 

2001-2003 data; for 2006-2008 it is 18.3 μg/m3. As this SIP demonstrates, attainment of the 15.0 

μg/m3 standard is expected to be reached by 2015. The Pittsburgh-Beaver Valley nonattainment

area design value was 16.9 μg/m3 for 2001-2003; for 2006-2008 it is 15.2 μg/m3. According to 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 2

the Pennsylvania Department of Protection PM2.5 SIP, the Pittsburgh-Beaver Valley area is 

projected to achieve a design value of 14.3 μg/m3 by 2010. 

Control measures that enable the Liberty-Clairton area to demonstrate attainment of the PM2.5

NAAQS include:

The Clean Air Interstate Rule (CAIR) or its replacement and the NOx “SIP Call” reducing 

interstate pollution transport;

Upgrades and shutdowns to United States Steel Corporation (U. S. Steel) Clairton Plant

batteries and quench towers

Other changes affecting the area not used in the modeled demonstration of attainment include:

Improved performance to RRI Energy Elrama Plant emission control system

Upgrades to U. S. Steel Edgar Thompson Plant

Pennsylvania Diesel Idling Law

Liberty-Clairton voluntary municipal vehicle diesel retrofits

Voluntary retrofit projects to several local diesel fleets including CSX Transportation, 

Port Authority of Allegheny County, Harsco Metals, and various construction vehicles

Allegheny County voluntary school bus retrofit program

Voluntary woodstove changeout program

Through these measures, Liberty-Clairton is anticipated to be in attainment by 2015, due to the 

heavy reliance on U. S. Steel Clairton Plant upgrades which will be completed by 2014.

The emission inventories used for this SIP was based on the regional MANE-VU (MidAtlantic/Northeast Visibility Union) inventories developed for long-range ozone, PM2.5, and haze 

planning. ACHD corrected the total primary PM2.5 (filterable + condensable) inventory for key 

sources in order to accurately address local emissions and incorporate reductions not previously 

included in regional modeling. This corrected inventory was then used to represent carbons in 

Liberty-Clairton, which have been shown to be the majority of excess primary PM2.5. Regional 

inventories for other precursors or components of PM2.5 were not modified for this SIP.

Years included in the inventory and modeling were 2002 for baseline case and 2014 for future 

projected case. For future case, uncorrected source emissions are as given in the 2012 MANEVU inventory, while ACHD corrections were made according to a 2014 timeline. The future 

case inventory may be considered a conservative hybrid of 2012 and 2014 since it does not 

account for possible additional reductions in the 2012-2014 timeframe.

The modeling demonstration utilized a combination of the regional Community Multiscale Air 

Quality (CMAQ) modeling using the MANE-VU inventory and local CALPUFF modeling using 

the local corrected ACHD inventory. Procedures for modeling and attainment tests were 

followed according to EPA Modeling Guidance of April 2007 and the Allegheny County Health 

Department (ACHD) Liberty-Clairton PM2.5 modeling protocol, dated October 15, 2007. 

Changes from the protocol are documented in this SIP. Work on the modeling was shared with 

an advisory modeling workgroup. Modeled impacts from regional and local modeling were 

combined on a conservation-of-mass basis, avoiding double-counting from different model runs. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 3

Attainment test methodology was used to combine final modeled results with actual monitored 

results over the 2000-2004 timeframe. Total mass was reconstructed by PM2.5 species by 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 the Southwest PA domain, including 878 tons of primary 

particulate from the nonattainment area, leading to the following future projected design values 

for Liberty and Clairton:

Projected Annual Design Values (Standard = 15.0 μg/m3)

Liberty 14.3 μg/m3

Clairton 11.8 μg/m3

Projected 24-Hour Design Values (Standard = 65 μg/m3)

Liberty 42 μg/m3

Clairton 27 μg/m3

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

Measures 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. 

A demonstration of Reasonable Further Progress is provided in this SIP. The most significant 

emission changes for primary PM2.5 will be the installation of new coke batteries and quench 

towers at the U. S. Steel Clairton Plant, along with the closure of older units at that facility.

This SIP contains a contingency plan that provides assurance that should the Liberty-Clairton 

area fail to meet a milestone, or fails 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 April 2011 Page 4

2. Regulation Changes

The following regulation changes were made to Allegheny County’s Article XXI in accordance 

with this SIP Revision. These regulation changes were enacted by County Ordinance 11-10-OR 

and became effective on May 24, 2010.

§2101.10 AMBIENT AIR QUALITY STANDARDS

The following ambient air quality standards are hereby adopted as part of this Article. The 

values specified herein represent minimum acceptable air quality, not necessarily desirable or 

satisfactory air quality. The adoption of these ambient air quality standards shall not in any 

manner relieve any person from the duty to fully comply with all requirements of this Article in 

areas where the concentration of air contaminants is less than such standards.

CONTAMINANT CONCENTRATIONS AVERAGED OVER

 1 yr. 3 mos. 30 days 24 hrs. 8 hrs. 3 hrs

PM-10

 National Primary & Secondary 50a 150a

 County 450d

 County Free Silica Portion 100d

PM-2.5

 National Primary & Secondary 15i 35i

. . .

i

as determined pursuant to 40 CFR 50.7 and Appendix N thereto

. . .

§2101.20 DEFINITIONS

. . .

"PM-2.5" means particulate matter with an aerodynamic diameter less than 

or equal to a nominal two and one-half (2.5) micrometers as measured by an 

applicable reference method, or equivalent or alternative method, specified by 

EPA or by method specified in this Article.

. . .

Additions are in large print, bold, and underlined.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 5

3. Problem Statement

3.1. 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. In 2005, the 

United States Environmental Protection Agency (EPA) determined that the Liberty-Clairton 

area, a 12 square kilometer subset of both Allegheny County and totally within the borders of the 

Pittsburgh-Beaver Valley PM2.5 nonattainment area, to be a separate PM2.5 nonattainment area. 

The area was designated separate from the surrounding Pittsburgh-Beaver Valley area because of 

how pollutant concentrations are affected by specific features of Liberty-Clairton.

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 population of the Liberty-Clairton area is about 25,000 

people, about 1% the population of the Pittsburgh Metropolitan Statistical Area (MSA).

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 seen between hilltop and 

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

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

downward flows. 

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

Clairton Plant is the largest coke plant in the country, producing roughly 4.7 million tons of coke 

annually. In addition the Liberty-Clairton area is also home to Koppers Industries, Inc.’s 

Clairton Tar Plant, seven permitted minor sources, as well as numerous minor sources that do not 

require operational permits. Mid-Continent Coal and Coke was previously classified as a major 

source during 2000-2002.

The Pittsburgh-Beaver Valley PM2.5 nonattainment area consists of Allegheny (without the 

Liberty-Clairton area), Beaver, Butler, Washington, and Westmoreland Counties, the 

municipalities of Washington, Elderton, and Plumcreek in Armstrong County, Monongahela 

Township in Greene County, and Taylor Township in Lawrence County.

The Liberty-Clairton PM2.5 nonattainment area was designated a separate nonattainment area 

from the surrounding Pittsburgh-Beaver Valley nonattainment area because, in addition to the 

regional air quality problem, there is a localized air quality issue in the local sources and the 

specific geologic and meteorological features of the area. Large industry located along the river 

sides in the valley. The sharp difference in elevation between the industrial and residential areas 

and the high hillsides surrounding them create a significant river basin, and spikes in localized 

PM2.5 concentrations coincide with temperature inversions.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 6

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

Figure 3-1 below.

Figure 3-1: Map of the Liberty-Clairton Area within the Pittsburgh-Beaver Valley Area
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 7

Figure 3-2 shows average daily PM2.5 concentration at multiple Allegheny County sites. Moon, 

South Fayette, North Park, South Park, and Springdale monitors were omitted due to their low 

sampling rate.

On many days the PM2.5 concentration measured at the Liberty monitor reads very similar to all 

the other monitors in the region. However, when the regional concentrations rise, Liberty 

concentrations clearly rise higher than any other site. This happens frequently enough, and 

extremely high enough (up to 50-60 μg/m3 above the other monitors on a 24-hour basis), that a 

control strategy needed to be considered for this area separate from, but in addition to, the 

control strategy for the rest of the Pittsburgh-Beaver Valley nonattainment area.

Figure 3-2: Daily PM2.5 Concentrations During the 2002 Base Year, Comparing Multiple 

Allegheny County Monitors

A temperature inversion occurs when the air at the bottom of the basin 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 air then becomes trapped at the lower

elevation, filling the basin. As the major and minor sources of the area continue to emit PM2.5

pollution, the lower, cooler air becomes buoyantly stable and unable to move upward to disperse 

into the regional flow. Figure 3.3 shows a comparison between base-year days in which PM2.5

2002 PM2.5 Daily Averages

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

1/1/2002

1/15/20021/29/20022/12/20022/26/20023/12/20023/26/2002

4/9/2002

4/23/2002

5/7/2002

5/21/2002

6/4/2002

6/18/2002

7/2/2002

7/16/20027/30/20028/13/20028/27/20029/10/20029/24/200210/8/2002

10/22/2002

11/5/2002

11/19/2002

12/3/2002

12/17/200212/31/2002

Date

PM2.5 Daily Concentration Average (ug/m3)

Hazelwood

Stowe

Harrison

North Braddock

Lawrenceville

Liberty
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 8

concentrations were above 50 μg/m3 at Liberty and days when temperature inversions greater 

than 3o Celsius occur.

Figure 3-3: 2002 Base Year Days with PM2.5 Concentrations Higher than 50 μg/m3 at the 

Liberty Monitor and Days with Inversions Greater than 3oC

Three days in June and July had PM2.5 concentrations greater than 50 μg/m3 without the presence 

of an inversion. However, as seen in Table 1, on the inversion-free high days the Liberty 

monitor was on average 10.2 μg/m3 higher than the urban Lawrenceville monitor, which is 

located in the city of Pittsburgh.

Additional inversion analysis is given in Appendix A. This analysis includes hourly continuous 

monitor averages with and without Liberty data during inversion days.

Distribution of Days in 2002 with High (>50 μg/m3) PM2.5 Readings

0

1

2

3

4

5

6

7

8

9

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

Month Number of Days

Number of High Days

Number of High Days with an inversion
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 9

Table 3-1: Comparison of 2002 Liberty and Lawrenceville PM2.5 Concentrations on NonInversion Days

Date Liberty 

(μg/m3)

Lawrenceville 

(μg/m3)

Difference 

(μg/m3)

6/11/2002 54.9 41.4 13.5

6/25/2002 62.6 51.7 10.9

7/18/2002 54.5 48.4 6.1

As per normal valley inversion action, the local PM2.5 is released into the upper atmospheric flow 

upon the inversion’s break. After the inversion break, the Liberty monitor returns to a level 

comparable to, and often less than, the concentrations measured at surrounding monitors. 

3.2. Monitoring

PM2.5 monitoring currently takes place at 8 different monitoring locations throughout Allegheny 

County. The Lawrenceville monitor, located roughly 2 miles from downtown Pittsburgh, is 

generally used to define urban concentrations of PM2.5, and can be used to judge regional 

concentrations. Two Federal Reference Method (FRM) PM2.5 monitors are used in the LibertyClairton area. The monitor at Liberty is located atop a school at high elevation near the center of 

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

in the western portion of the area. Both were violating the annual PM2.5 standard of 15 μg/m3 

during the design year of 2002. FRM monitors located to the west and to the south of the area 

(South Park and Forward) have monitored attainment of both standards. Appendices A 

(monitored data) and C (model protocol) contain more details of monitor sites and data.

Liberty and Clairton annual design values are given below in Figure 3-4. The Clairton monitor 

is located in the general upwind direction of the Liberty monitor, causing readings to be nearly 4

μg/m3 lower at Clairton than at Liberty for the 2007-2009 Design Value. Clairton concentrations 

show a distinct decline since the ’00-’02 average, whereas movement at the Liberty monitor is 

smaller. Though located within the Liberty-Clairton nonattainment area, the Clairton monitor 

reflects the decline consistent with the entire Pittsburgh-Beaver Valley area, whereas the Liberty 

monitor remains constant due to the local sources and the meteorological conditions of the area. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 10

Figure 3-4: PM2.5 Annual Design Values Since 2000

3.3. Data Analysis

The average 5 μg/m3 difference between annual PM2.5 concentrations in Liberty and other 

monitors within the Pittsburgh-Beaver Valley nonattainment area can be attributed to the spikes 

in daily averages at Liberty. Primarily caused by inversions, as shown in Section 3.1, the days 

which can range as high as being 30 μg/m3 above Lawrenceville monitor data cause the annual 

average increase. Days which are not affected by inversions show Liberty following surrounding 

daily averages. Analyzing PM2.5 concentrations and inversion days shows a strong correlation 

between the two. 

3.3.1. Regional, Urban, and Local Concentrations

The localized excess in the Liberty-Clairton area has been determined through speciation data

analysis. Up to 75% of ambient PM2.5 concentrations in the Pittsburgh-Beaver Valley 

Metropolitan Statistical Area (MSA) can be attributable to upwind sources in Ohio, West 

Virginia, Indiana, and Michigan. This becomes roughly 11-13 micrograms per cubic meter of all 

the PM2.5 pollution in the Pittsburgh-Beaver Valley nonattainment area. The same is true about 

the Liberty-Clairton nonattainment area, as it is a part of the Pittsburgh-Beaver Valley MSA. On 

non-inversion days, pollutant levels in the Liberty-Clairton area match those of the greater 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 11

region. However, the inversion-caused spikes average out to add roughly 5 μg/m3 to the annual 

average, causing the nonattainment (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 1.1).1)

A comparison of regional, urban, and local concentrations shows differences in the LibertyClairton area to the surrounding areas. The Lawrenceville monitor, located in the city of 

Pittsburgh, serves as a baseline for the regional averages of PM2.5. The average 16.1 μg/m3 

PM2.5 concentration at the Lawrenceville monitor, impacted both by urban excess and the 

average 11-13 μg/m3 from out-of-state sources, increases to 20.7 μg/m3 at the Liberty monitor, 

signaling a localized excess of emissions at Liberty of 4.4 μg/m3. Figure 3-5 shows the 

speciation of both monitors, including the localized excess at Liberty.

Figure 3-5: Regional, Urban, and Local PM2.5 Concentrations

The following Figure 3-6 shows a close-up of the localized excess at Liberty by species (i.e., the 

subtracted species shown in Figure 3-5). The “other” component represents the difference 

between total mass and the sum of the major species. “Other” component can include particle 

bound water, trace elements, or compounds not measured.

 

1 Report can be found online at http://www.achd.net/airqual/pubs/pdf/pmf0106.pdf and in Appendix E.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 12

Figure 3-6: Localized Excess at Liberty

3.3.2. Speciation of PM2.5 Data

Results from the Liberty PM2.5 speciation monitor show that carbons, ammonium, and some 

trace elements are higher in the Liberty-Clairton area than in other monitored areas by 4 to 5 

μg/m3. An in-depth analysis of speciated PM2.5 components in Allegheny County can be found 

in the report PM2.5 Chemical Speciation and Related Comparisons at Lawrenceville and Liberty: 

18-Month Results.2

 

2 Report can be found online at http://www.achd.net/airqual/pubs/pdf/speciation_report.pdf and in Appendix E.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 13

4. Control Strategy

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

Liberty-Clairton nonattainment area.

Clean Air Interstate Rule (CAIR) – EPA’s CAIR (70 FR 25162, May 12, 2005) was remanded 

to EPA for revisions by the United States Court of Appeals for the District of Columbia on 

December 23, 2008. EPA has proposed the Transport Rule (TR) as a replacement rule to CAIR,

to be effective in 2011. The Transport Rule is expected to be as strict as or stricter than the 2005 

CAIR. A comparison of CAIR and proposed TR emissions and controls can be found in the 

weight of evidence section of this document.

Pennsylvania transitioned from the NOx SIP Call to the federal CAIR in 2009. CAIR is to 

provide the incentive for large electric generation units (EGUs) to reduce emissions below 2002 

levels throughout the 28-state CAIR region. Pennsylvania and other nearby states were required 

to adopt a regulation implementing the requirements of the CAIR or an equivalent program. 

EPA approved the Pennsylvania CAIR program on December 10, 2009. On April 28, 2006, the 

EPA promulgated Federal Implementation Plans (FIPs) to reduce the interstate transport of NOx

and SO2 that contribute significantly to nonattainment and interfere with maintenance of the 8-

hour ozone and PM2.5 NAAQS. The EGUs in Pennsylvania will be regulated under the FIP until 

the EPA approves a SIP revision for the implementation of CAIR for the affected EGUs, at 

which point the approved CAIR SIP revision will supersede the FIP requirements in 

Pennsylvania. The Pennsylvania CAIR regulation was published in the Pennsylvania Bulletin on 

April 12, 2008. (38 Pa.B. 1705). The Department submitted the SIP revision to the EPA on May 

23, 2008. 

Interstate Pollution Transport Reduction – In response to the federal NOx SIP call rule, 

Pennsylvania and other covered states adopted NOx control regulations for large industrial 

boilers and internal combustion engines, EGUs, and cement plants. The regulation covering 

industrial boilers and electric generators required emission reductions to commence May 1, 

2003, while the regulation covering large internal combustion engines and cement plants 

required emission reductions to commence May 1, 2005. The EPA approved these regulations, 

found in 25 Pa. Code Chapter 145, on August 21, 2001 (66 FR 43795) and September 29, 2006

(71 FR 57428). 

U. S. Steel Mon Valley Works – 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, requiring a number of actions at the U. S. Steel Mon Valley Works Clairton and Edgar 

Thomson Plants in response to a number of visible emissions and opacity violations. These 

actions at the U. S. Steel Clairton Plant include 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 actions used in the attainment demonstration are as 

follows:
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 14

U. S. Steel Clairton Plant:

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 will replace 25 heating walls on Battery 19 by October 31, 2012. 

The battery will meet its opacity limits by December 31, 2012, including, as necessary, 

implementing an advanced patching plan.

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.

Other actions by U. S. Steel included in the attainment demonstration are as follows:

U. S. Steel Clairton Plant:

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 by June 30, 2010.

Other actions not included in the attainment demonstration but included in the U. S. Steel 

March 2008 consent order and agreement (amended in September 2010) are as follows:

U. S. Steel Clairton Plant:

Battery 15 – U. S. Steel completed three rounds of an enhanced preventive maintenance 

refractory repair plan, and the battery achieved compliance with its opacity limits by 

December 31, 2008.

Battery 20 – 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, as necessary, an advanced 

patching plan and a revitalization plan of the battery heating system.

U. S. Steel Edgar Thomson Plant:

Basic Oxygen Process (BOP) – U. S. Steel implemented an enhanced operating and 

maintenance plan for the mixer baghouse and gas cleaning system, received an installation 

permit, and completed construction of an upgrade to the BOP emission capture system, and 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 15

achieved compliance with the visible emission standards at the BOP roof monitor by June 30, 

2009.

Ladle metallurgical furnace (LMF) – U. S. Steel has implemented an enhanced operating 

and maintenance plan for the LMF, received an installation permit for an upgrade to the LMF 

baghouse, and will complete the installation by August 31, 2010.

Other measures not included attainment plan are as follows: 

RRI Energy Elrama Plant – In 2007, Orion Power Midwest (now RRI Energy) and the PA 

DEP entered into a consent order and agreement to address exhaust stack opacity. The consent 

order and agreement requires Orion Power Midwest to continue efforts to improve scrubber 

performance and to enhance boiler and ESP performance. This consent order and agreement did 

not require PADEP plan approvals, and the impact is difficult to calculate, so the emission 

change was not included, however this should improve air quality in the nonattainment area.

Wood Stove Changeout Campaign – In 2005 through 2007, ACHD participated in EPA’s 

Wood Stove Changeout Campaign, replacing 176 older woodstoves in the Southwestern

Pennsylvania area with newer, cleaner units, resulting in an approximate 9 tons per year of total 

particulate removed.

Harsco Metal – Harsco Metals North America provides trucking for U. S. Steel. With 

American Recovery and Reinvestment (ARRA) funds, Harsco will voluntarily install diesel 

particulate filters on 11 dump trucks operating in and around U. S. Steel's Mon Valley Works. 

Once upgraded, these dump trucks will be 90-percent less polluting than they are today. It is 

estimated that these diesel particulate filters will remove 0.06 tons of particulate matter per year, 

0.20 tons of carbon monoxide per year, and 0.91 tons of hydrocarbons per year.

Voluntary Diesel Retrofits – An ACHD fund has been allocated to provide voluntary diesel 

retrofits to municipal vehicles in the municipalities within the Liberty-Clairton nonattainment

area. It is unknown at this time how many vehicles will be retrofitted, and the amount of 

particulates that will be reduced.

CSX Transportation – With ARRA funds, CSX Transportation will replace one vintage diesel 

switcher locomotive without emission controls with a two-engine GenSet switcher locomotive 

engine, cutting 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 will also save 15,000 gallons of 

diesel fuel annually and provide quieter operation for the nearby residents of McKeesport.

The Port Authority of Allegheny County – The Port Authority of Allegheny County will use 

ARRA funds for replacing two 1996-model transit buses with 2010-model cleaner diesel hybrid 

electric buses and to repower nine 2003-model diesel buses with engines that meet the new, 

higher 2007 emission standards. This will reduce particulate matter pollution by approximately 

0.1 tons per year, carbon monoxide by 2.8 tons per year, and nitrogen oxides by 6.8 tons per 

year.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 16

Constructors Association of Western Pennsylvania – Constructors Association of Western 

Pennsylvania will use ARRA funds for retrofit technologies – engine repowers, upgrades, and 

diesel particulate filters – to upgrade 23 diesel-powered, heavy non-road construction equipment 

in Western Pennsylvania. The various upgrades will reduce particulate matter pollution by 1.8 

tons per year, carbon monoxide by 14.6 tons per year, hydrocarbons by 2.09 tons per year, and 

nitrogen oxides by 9.73 tons per year.

The City of Pittsburgh – The City of Pittsburgh will retrofit approximately 33 diesel engine 

municipal waste haulers with emission-reducing technology.

Diesel Idling Regulations – Both Allegheny County and Pennsylvania recently adopted a statewide ban on unnecessary diesel idling. Drivers of diesel engine vehicles can be reported to 

ACHD and can be fined up to $500 if they are found to idle unnecessarily for more than 5 

minutes in a one-hour period. Outreach and public education for these new regulations are 

currently underway. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 17

5. Explanation of Proposed Attainment Date

Section 172(a)(2) of the CAA states that an area’s attainment date “shall be the date by which 

attainment can be achieved as expeditiously as practicable, but no later than 5 years from the 

date such area was designated nonattainment.” Liberty-Clairton was designated as 

nonattainment for annual PM2.5 as of 2005. Therefore the initial 5-year attainment date for PM2.5

would be 2010. 

An agency may request an extension of that attainment date for up to 5 years, with reason for the 

need of this extension. This SIP proposes an attainment date of 2015. The extended attainment 

date is necessary in this case in order for U. S. Steel to complete construction of new equipment 

as per consent order and agreement.

The consent order and agreement between ACHD and U. S. Steel made in March 2008 outlined

plans to shut down Batteries 7, 8, and 9 and replace them with a new Battery C, based on a 

newer and cleaner design. This project reduces emissions of direct PM2.5 by approximately 208 

tons per year, at a cost of about $500 million.

As part of an amendment to the consent order and agreement (in September 2010), U. S. Steel 

additionally agreed to construct new low emission quench towers for Batteries 13-15 and 

Batteries 19-20. The new Quench Towers 5A and 7A will reduce emissions of direct PM2.5 by 

593 tons per year. The quench tower installations are scheduled for completion by December 31, 

2013.

These upgrades represent an extensive and expensive modernization of this facility. No 

combination of additional source changes or upgrades in the nonattainment area can provide the 

tonnage of emissions decreases or bring the date forward by a year. Therefore, the attainment 

date must be extended from 2010 to 2015.

Modeling in this SIP includes regional modeling done by MANE-VU, which contains CAIR, a 

program now remanded to EPA. EPA has proposed the Transport Rule (TR) as a replacement 

rule to CAIR, to be effective in 2011. This should not change the attainment date, either to move 

it forward or to delay it further. The Transport Rule is expected to be as strict as or stricter than 

CAIR. A comparison of CAIR and proposed TR emissions and controls can be found in the 

weight of evidence section of this document.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 18

6. 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, which includes the PittsburghBeaver Valley PM2.5 nonattainment area, the remainder of southwest 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 one minor source that was formerly classified as a major source (Mid-Continent 

Coal and Coke). Mid-Continent was kept in the inventory for consistency between baseline and 

future cases. Three additional minor sources were included as PM2.5 point sources in the 

modeling inventory but are not included in this section.

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 both the regional 

MANE-VU inventories and projections along with ACHD inventories for stationary point 

sources. Emissions given are “actual” values based on pollutant emission factors and 

throughputs or capacities of each emission source. The emissions values do not necessarily 

represent permitted or “allowable” limits.

The year 2002 was used for baseline emissions inventory and 2014 for the projected inventory 

for the Liberty-Clairton area, based on local direct PM2.5 controls. Regional projections utilized 

on-the-books/on-the-way (OTB/W) controls through the 2012 timeframe. Since no additional 

projections are available at the time of this SIP, and since Liberty-Clairton controls focus on 

direct PM2.5, regional projections for 2012 were used for precursors and non-point PM2.5

emissions in combination with local projections for 2014 for stationary point PM2.5 emissions. 

This is discussed more in the previous section (Section 5) and in the modeling section (Section 7) 

of this SIP.

Regional controls for SO2 and NOx in the MANE-VU inventory were based on CAIR. EPA has 

proposed the Transport Rule (TR) as a replacement rule to CAIR, to be effective in 2011. The 

Transport Rule is expected to be as strict as or stricter than CAIR. A comparison of CAIR and 

proposed TR emissions and controls can be found in the weight of evidence section of this 

document.

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

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

baseline and projected inventories are given in Appendix G.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 19

Stationary point sources are sources for which ACHD collect individual emissionsrelated information. Revisions were made to 2002 point sources data based on newer 

estimates that do not reflect originally submitted data. Additionally, the future case 

includes revisions that were not part of the regional projections.

Area sources, which 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. 

The regional baseline 2002 and projected 2012 emissions were used for area source 

emissions. Area sources were given by county in the regional inventories – emissions 

were apportioned to the Liberty-Clairton area based on population counts.

3

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. The regional baseline 2002 and 

projected 2012 emissions were used for nonroad emissions. Similar to area sources, 

nonroad emissions were apportioned to the Liberty-Clairton area based on population.

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

motorcycles. This data was compiled by PA DEP for Southwestern PA, with separate 

estimates for the Pittsburgh-Beaver Valley and Liberty-Clairton areas. For these 

estimates, 2009 was used as the future projected case and was used in this inventory since 

no additional data is available. Mobile source vehicle miles traveled (VMT) and 

emissions were estimated using GIS and the PennDOT Roadway Management System 

(RMS). Additional mobile source emissions information is given in Appendix F.

Point sources and corresponding revisions used in the ACHD local CALPUFF modeling are 

provided in Appendix H. Additionally, emissions inventories used for Reasonable Further 

Progress (RFP), including area/nonroad/mobile, have been provided in Appendix H. 

Emissions inventory summaries for baseline and future projected cases are shown in Tables 6-1 

and 6-2 on the following page.

 

3 Taken from the U.S. Census, year 2000. Liberty-Clairton represents 1.69% of the total Allegheny County 

population.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 20

Summary of 2002 Emissions Inventory

Table 6-1 below shows emissions totals for the Liberty-Clairton area for the baseline case

(2002). These emissions represent sources only within the 5-municipality Liberty-Clairton area, 

not the larger modeled area.

Table 6-1: Baseline 2002 Emissions (Tons/Year)

Liberty-Clairton Area

(2002) PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 2201.438 2745.678 1358.522 5786.190 432.735 299.714

Area Sources 36.506 151.173 81.962 80.176 336.467 7.416

Nonroad Sources 23.005 29.016 16.170 227.673 119.244 0.078

Mobile Sources 4.918 7.228 12.077 283.422 200.841 13.867

Totals 2265.867 2933.095 1468.731 6377.461 1089.287 321.075

Summary of 2014 Emissions Inventory

Table 6-2 below shows emissions totals for the Liberty-Clairton area for the future projected case 

(2014). Similar to the baseline inventory, these emissions represent sources only within the 5-

municipality Liberty-Clairton area.

Table 6-2: Future Projected 2014 Emissions (Tons/Year)

Liberty-Clairton Area

(2014) PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 1328.785 1881.461 1459.146 5282.002 581.492 255.456

Area Sources 35.464 157.867 86.464 86.239 307.013 8.176

Nonroad Sources 21.500 27.789 3.034 169.006 83.335 0.093

Mobile Sources 2.749 4.919 1.409 134.079 98.997 14.367

Totals 1388.498 2072.036 1550.053 5671.326 1070.837 278.092
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 21

7. Modeling Procedures

7.1. Design

Allegheny County Health Department (ACHD) followed modeling procedures outlined by the 

PM2.5 Model Protocol, Liberty-Clairton Nonattainment Area (given in Appendix C) and by the 

EPA Modeling Guidance4. The modeling utilized a combination of regional CMAQ modeling 

using the MANE-VU inventory and local CALPUFF modeling using a local revised ACHD 

inventory. ACHD used the EPA-preferred Version 5.8 of the CALPUFF/CALMET model.

7.1.1. Protocol

Deviations or clarifications made to the modeling design since the development of the protocol 

are listed below: 

2012 was selected in place of 2009 for the future case MANE-VU inventory and CMAQ 

impacts to incorporate additional regional sulfate/nitrate reductions in the 2009-2012 

timeframe

The MM5 prognostic data was used for upper air data in CALMET (NOOBS=1 mode)

instead of solely using PIT Airport upper air data [airport upper air data is already 

incorporated into MM5 data]

Dimensions for the long-range transport domain were expanded from 140 km to 150 km, 

in order to fully utilize the supplied MM5 data and to include additional EGUs in SW PA 

and Northern WV

Allegheny County Airport surface meteorological data were included along with PIT 

Airport data in the 150 km CALMET meteorological processing

R1, R2, RMAX1, and RMAX2 variables were set to 3.0 m for the 150 km CALMET 

domain (double the 1.5 m for the 20 km domain values) -- this was not specified in the 

model protocol

Spacing for the “CMAQ-equivalent” receptor grid in CALPUFF was set to 500 meters

Instead of shifting the “CMAQ-equivalent” grid receptors slightly to the southwest, an 

additional row of receptors were added within the CMAQ grid area (adding 24 receptors 

to the bottom of the grid, covering the Clairton nearby area)

 

4

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 April 2011 Page 22

For nitrates, sulfates, crustal (other primary PM2.5, or “OPP”), direct RRFs from the 

CMAQ modeling were used; for ammonium and water, indirect (calculated) values were 

used for both baseline and future cases

For the CALPUFF-modeled primary PM2.5, modeled values were combined with CMAQ 

total carbons (elemental and organic); RRFs were then applied on a total carbon basis

Speciation results for 2003-2004 were used for the species reconstruction by composition

CALMET did not support 2001 land use data since the development of the protocol, so 

USGS NLCD 1992 data was used for land use (as proposed in the protocol)

An aerial map of the modeling domains is shown below in Figure 7.1, by MM5 grid, 150 km 

domain, and 20 km domain.

Figure 7-1: Modeling Domains
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 23

A map of the CALMET modeling domains by land use and terrain is shown in Figure 7-2 below

(note: land use codes are those used by CALMET, not USGS). The 20 km x 20 km domain is 

seen by the darker terrain contours near the center within the larger 150 km x 150 km domain. 

Figure 7-2: Modeling Domains by Land Use and Terrain

7.1.2. Years Modeled

Years modeled by ACHD were 2002 for baseline case and 2014 for future projected case. For 

the future case, uncorrected source parameters were as given in the 2012 MANE-VU inventory. 

[Accordingly, CMAQ impacts were as given in the 2012 regional results.] Revisions to local 

sources were made according to a 2014 timeframe, so the resulting future case ACHD inventory 

is a hybrid of 2012 and 2014 emissions.

It is assumed that 2012 emissions for uncorrected sources are representative through year 2014. 

Emissions of SO2 and NOx are steadily declining since 2002 due to regional controls. Only

crustal component (fine soil, road dust, or “other primary particulate”) is projected to increase, 

but by less than 1% per year. Since crustal component represents only a small portion of PM2.5

at Liberty (3% in baseline timeframe), increases to crustal concentrations should be insignificant 

in comparison to concentrations of other major PM2.5 components.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 24

7.2. Methodology

The modeling methodology was based on excess primary PM2.5 leading to the high 

concentrations at the Liberty and Clairton FRM monitors. The EPA Modeling Guidance outlines 

techniques that can be used to model primary PM2.5 – this section describes the steps used to 

model the Liberty-Clairton area. 

7.2.1. Sources Modeled

Since PM2.5 in SW PA is composed of a combination of transported and locally-derived 

components, a large array of stationary point sources were included in the modeling inventories. 

The modeling domain included sources within a 150 km x 150 km area, encompassing SW PA 

along with parts of OH and WV. Emissions used were total “actual” primary PM2.5 (filterable + 

condensible) for baseline and future projected cases.

The MANE-VU base and future inventories were reviewed for accuracy in coordinates, 

emissions, and stack parameters. Sources were reviewed in comparison to EPA’s National 

Emissions Inventory (NEI) for 2002, as well as the ACHD 2002 inventory (Allegheny County 

sources only). Corrections made to the MANE-VU inventory for use in the corrected modeling 

are given in Appendix H, along with full inventories.

Regional controls for SO2 and NOx in the MANE-VU inventory were based on CAIR. EPA has 

proposed the Transport Rule (TR) as a replacement rule to CAIR, to be effective in 2011. The 

Transport Rule is expected to be as strict as or stricter than CAIR. A comparison of CAIR and 

proposed TR emissions and controls can be found in the weight of evidence section of this 

document.

Sources within the 20 km x 20 km domain, centered about the Liberty monitor, were also 

modeled as more representative source types (lines, volumes, etc.), based on previous modeling 

studies performed by ACHD. Many point (stack) sources also included building parameters to 

address possible downwash.

7.2.2. Combination of Impacts

Due to the large number of revisions made to the inventories, ACHD elected to combine 

modeled impacts from all point sources. This technique allows for proper adjustments for both 

near-field and distant sources, while keeping the integrity of the regional CMAQ results.

The modeled impacts for total carbons were combined using a conservation-of-mass technique 

that avoids double-counting. Average impacts from the uncorrected MANE-VU inventory 

across an “equivalent grid” were subtracted from the CMAQ impacts on a concurrent basis. The 

corrected ACHD inventory impacts for Liberty and Clairton were then added to the CMAQ 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 25

results, creating sub-grids of the original CMAQ grid cell. This is shown visually in Figure 7-3 

on the following page.

CMAQ - Equivalent + Liberty, Clairton

 

Figure 7-3: Combination of Modeled Impacts for Total Carbons

7.2.3. Reconstruction of Species

Modeled total primary PM2.5 was used to represent total carbon in the modeling due to the 

analyses shown in the Speciation and PMF reports (Appendix E). The speciation analysis was 

performed using data in the 2003-2005 timeframe, and carbons represented 74% of the measured 

excess at Liberty. The carbon-rich factor from the PMF source apportionment report represents 

24% of the total PM2.5 (equating to approximately 5 μg/m3 in the baseline timeframe).

Ammonium, chlorine, and “other” component are also small portions of the localized excess. 

Although these species are not modeled directly, they are accounted for in the reconstruction of 

species using the SANDWICH method given in the EPA Modeling Guidance. Reasoning is 

listed below: 

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

species

Ammonium and chlorine concentrations have been shown to peak simultaneously with 

carbons, and can likely be attributed to similar sources; controls to carbons would likely 

apply to associated compounds

“Other” component represents unknown mass from the speciation monitor, likely due to 

water associated with hygroscopic organics

Furthermore, the recommended method in the EPA Modeling Guidance for reconstructing 

ammonium and water is by indirect calculation (dependent on other species). A direct 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 26

ammonium method using measured/modeled ammonium is included as an option, but it was not 

used for the following reasons:

There was much uncertainty in the inventories for ammonia and chlorinated compounds

and the particle formation of these compounds within the Liberty-Clairton area

The CALPUFF modeling was performed for primary PM2.5, with no chemical 

transformation; inclusion of ammonia and/or hydrochloric acid would require 

transformation

CMAQ-modeled ammonium reductions are based primarily on reductions in associated 

sulfate and nitrate and would not necessarily apply to excess primary ammonium

Future speciation analyses, reconstruction techniques, and inventories that incorporate more 

species may be developed for future SIPs.

The SANDWICH species reconstructions are shown in detail in the Attainment Demonstration 

section (Section 8).

7.2.4. Modeled Source Groups

Sources in the MANE-VU and ACHD inventories were apportioned to source groups for the 

modeling. A summary of source groups by model input file is provided in Appendix I. Source 

groups were generally assigned as follows: 

Distant sources were grouped by geographic region (distant EGU sources were modeled 

as a specific group)

Near-field sources within or adjacent to the Liberty-Clairton area were grouped by 

facility or source type

A map of sources outside Allegheny County (excluding EGUs) is shown in Figure 7-4 for 

baseline case with corrected coordinates. These sources were grouped by county (or by state for 

OH and WV sources).
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 27

Figure 7-4: Map of Modeled Sources Outside Allegheny County (no EGUs)
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 28

A map of EGUs within the modeled area is shown below in Figure 7-5, for baseline case with 

corrected coordinates and facility names. These sources represent the majority of PM2.5

emissions in the tri-state PA/OH/WV area.

Figure 7-5: Map of Modeled EGUs
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 29

A map of Allegheny County sources (excluding RRI Energy Cheswick) is shown below in 

Figure 7-6 for baseline case with corrected coordinates. Sources outside the 20 km domain were 

grouped by geographical region.

Figure 7-6: Map of Allegheny County Modeled Source Groups and 20 km Domain
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 30

A map of sources within the 20 km domain is shown below in Figure 7-7 for baseline modeled 

case with corrected coordinates. Labels are given for selected source groups or areas.

Figure 7-7: Map of Modeled 20 km Domain Sources/Groups
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 31

Building parameters were also included for all point sources within a 2.5 km radius of the 

Liberty monitor (5 km diameter) and for selected sources within or beyond a 5 km radius (10 km 

diameter). A map of near-field sources within or adjacent to the Liberty-Clairton area is shown 

below in Figure 7-8; sources shown in red included building parameters for stacks that may 

experience downwash. U. S. Steel Edgar Thomson sources (not shown on map) also included 

building parameters. The Liberty monitoring site is indicated by the white diamond in the 

center.

Figure 7-8: Map of Near-Field Sources with Building Parameters
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 32

7.2.5. Emissions Totals

Total modeled primary PM2.5 emissions by area (or group) for the corrected baseline and future 

cases are shown in Table 7-1 below.

Table 7-1: Modeled Emissions Totals

Source Group/Area

Baseline 2002 

Primary PM2.5

(tons)

Future 2014

Primary PM2.5

(tons)

Allegheny Co.* 873 927

Armstrong Co. 54 66

Beaver Co. 250 278

Butler Co. 321 339

EGUs (Distant) 51779 27934

EGUs (Near-Field)** 746 691

Fayette Co. 115 145

Greene Co. 146 157

Lawrence Co. 529 718

Ohio 372 367

Washington Co. 120 146

Westmoreland Co. 241 286

U. S. Steel Clairton 2186 1304

U. S. Steel Edgar Thomson 961 912

West Virginia 7570 6435

TOTAL 66263 40705

* Allegheny Co. without U. S. Steel Edgar Thomson, U. S. Steel Clairton, 

and RRI Energy Cheswick

** Near-field EGUs include RRI Energy Elrama and Allegheny Energy Mitchell plants

7.2.6. Combination of Impacts

For use in the calculation of design values, locally-modeled primary PM2.5 impacts from 

CALPUFF were combined with CMAQ modeled results. For annual results, impacts were 

combined on a quarterly average basis. For the 24-hour results, impacts were combined on an 

hourly basis, and daily averages of the hourly values were used for the high-day analysis 

described later in this section. [Hourly impacts were used for the daily averages to ensure 

alignment of the 24-hour periods with no time differences between Local Standard Time (LST) 

and Greenwich Mean Time (GMT); MM5 prognostic data was formatted in GMT.]

CMAQ modeled values are given as one value per species for any given time period. Grid 

averages from the CALPUFF modeling were based on the average of all receptors within a 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 33

selected grid, i.e., the CALPUFF-modeled “CMAQ-equivalent” value for any time period is the 

average of all 600 receptors. For the nearby receptor grids, the Liberty value is an average of 40 

receptors and the Clairton value is an average of 51 receptors.

7.2.7. Aggregation of Source Groups and Domains

Local CALPUFF modeling was performed on a source group basis in two modeling domains 

(long-range 150 km and near-field 20 km). Impacts needed to be combined accordingly for each 

receptor grid and modeled case (baseline or future) prior to combination with CMAQ values. 

The following steps were taken to combine impacts from model output files:

1) The post-processor CALSUM was used to combine outputs from different source 

groups in each modeled domain

2) The post-processor CALPOST was used to generate receptor impacts from the 

CALSUM files by averaging period (quarterly or hourly) for each domain

3) Receptor impacts from the 150 km and 20 km domains were summed via 

spreadsheet

4) Combined-domain receptor impacts were then averaged by time period (quarterly 

or daily)

5) Steps 1 and 2 were repeated for each grid and modeled case 

For example, to generate baseline receptor impacts from the Liberty nearby grid for use in the 

annual test, CALSUM was used to combine the source group output files for each domain. 

Receptor impacts were then generated by CALPOST for each domain on quarterly average 

bases. The average receptor impacts from the 150 km and 20 km runs were summed via 

spreadsheet for each quarter. The averages of all receptors by quarter were then used as the 

Liberty Nearby quarterly values for baseline case.

[Note: The two nearby grids were actually run as one grid in the model files in order to conserve 

run time. Impacts were separated in the post-processing (Liberty nearby receptors: 1-40, 

Clairton nearby receptors: 41-91).]

Model input/output and post-processing files have been given in Appendix I (or on the 

accompanying DVD).

7.2.8. Combination of Annual Impacts

For the annual basis, quarterly average CALPUFF-modeled “CMAQ-equivalent” values were 

first subtracted from the total carbon (elemental + organic) quarterly averages from the CMAQ 

modeling. Quarterly averages from each of the nearby areas (Liberty and Clairton) were then 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 34

added to the result. This formula was used for both baseline and future projected cases. The 

combined impacts from each area are then used to generate Relative Response Factors (RRFs) 

for total carbons.

7.2.9. Combination of 24-Hour Impacts

Using the same methodology as the annual combination of impacts but on a different time scale, 

hourly CALPUFF-modeled “CMAQ-equivalent” averages were subtracted from each CMAQ 

hourly total carbons value. Hourly averages from the nearby runs were then added to the result, 

and daily averages (midnight-to-midnight 24-hour periods) were created from the hourly 

combinations.

For use in the 24-hour test, the top 25% of high modeled days per quarter were used for RRFs. 

Therefore, high days by sum of all modeled species were ranked by quarter. [Full 24-hour 

combination of impacts is given electronically on the DVD.] The top 23 days in each quarter 

were then used to generate average high-day modeled values for the species used for direct RRFs 

(sulfate, nitrate, OPP, and carbons).
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 35

8. Attainment Demonstration

8.1. Monitored Data Assumptions

The following assumptions were made for the Liberty and Clairton monitored data for use in the 

annual and 24-hour standard attainment tests.

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

monitored areas. The Liberty species compositions are representative of Clairton, but at 

smaller overall concentrations. Liberty species compositions are therefore used with 

Clairton weighted FRM values in the design value calculation.

Liberty speciation data is available from 4th quarter 2003 through 4th quarter 2004. It is 

assumed that these compositions are representative of the entire baseline timeframe of 

2000-2004.

Liberty speciation data recovery for 4th quarter 2003 is 67%, below the recommended 

recovery percentage of 75%. Since compositions are similar to that of 4th quarter 2004, 

and for a more robust speciation data set, it has been included in the species composition 

calculations.

Clairton FRM data is available for 2001-2004. It is assumed that these years are also 

representative of the year 2000, which is excluded from the weighted FRM values.

No 4th-of-July peaks or other valid anomalies are evident in the FRM and speciation data. 

All data has been included in the design value calculations.

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

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

8.2. Annual Attainment Test Methodology

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

EPA Modeling Guidance.5 Species reconstruction is based on the SANDWICH (sulfate, 

adjusted nitrate, derived water, inferred carbonaceous material balance approach) technique. The 

steps for the annual SMAT are listed below:

Calculate 5-year weighted FRM quarterly averages. This is the 3-year average of the 

2000-2002, 2001-2003, and 2002-2004 3-year quarterly averages. This is done for the 

Liberty and Clairton FRM monitored values.

 

5 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 April 2011 Page 36

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, 

other primary PM2.5 (OPP), and elemental carbon, and concurrent FRM values are 

calculated. Quarterly averages for measured organic carbon are also calculated 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:

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

calculated from quarterly sulfate, retained nitrate, and retained 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)

NH4r = DON*SO4 + 0.29*NO3r
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 37

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 

species, then recalculating species concentrations based on weighted FRM values.

Calculate quarterly Relative Response Factors (RRFs) from modeling. For this 

demonstration, direct RRFs are calculated from baseline and future CMAQ modeling for 

sulfate, nitrate, and OPP. The combined ACHD modeling is used to generate total 

carbons RRFs (applied to sum of elemental and OCMmb).

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

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

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

averages.

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 the 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.

8.3. 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 quarterly averages instead of overall 

averages, based on EPA Modeling Guidance.

Indentify observed (monitored) high days in baseline timeframe. This is done by 

selecting the highest day in each quarter (for each FRM monitor) that is less than or equal 

to the 98th-percentile value for the corresponding year (2000-2004). This method focuses 

on high days that represent seasonal highs rather than overall maximums.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 38

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 25% (3 samples) 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 days monitored observed days. The 

end results are quarterly species compositions for each year (2000-2004).

Calculate quarterly Relative Response Factors (RRFs) for high days from modeling. The 

high modeled days are identified after summing all components, included the combined 

carbons from the ACHD modeling. The top 25% (23 days) by quarter are then averaged 

for sulfate, nitrate, OPP, and carbons. RRFs are calculated from the baseline and future 

modeled results.

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 RRFs, and ammonium and PBW concentrations are recalculated from the future sulfate, nitrates.

Calculate future design value. Identify future 98th-percentile days, calculate the 5-year 

weighted average of the projected 98th-percentile days. Similar to the annual weighted 

FRM value, the weighted average is the 3-year average of the 2000-2002, 2001-2003, and 

2002-2004 3-year averages, rounded to the nearest integer for comparison to the 24-hour 

standard.

8.4. Annual Standard Test Results

A summary of the annual design value calculations for Liberty is given in Tables 8-1 to 8-4. 

Spreadsheets showing the expanded design value calculations are given in Appendix J. All 

compositions and design values are given in μg/m3, while RRFs are dimensionless ratios.

Baseline quarterly compositions are calculated by the sum of the major species. RRFs are 

calculated by ratios of the modeled future case to baseline case results. The future case results 

are then calculated by multiplying the baseline results by the corresponding RRF by species.

Note: Attainment tests results using regional modeling data without Liberty-Clairton local 

modeling showed nonattainment for both 2009 and 2012. Therefore, a local modeling analysis 

was necessary in order show compliance for this SIP.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 39

Table 8-1: Baseline Quarterly Compositions – Liberty Annual

QTR Total PM2.5 Blank

Organic 

Mass (by 

Balance)

Elemental

Carbon

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP) Ammonium Water

1Q 18.2778 0.5 4.8986 1.5001 6.3987 5.0112 1.9749 0.6142 2.2179 1.5608

2Q 22.0970 0.5 6.4918 3.0769 9.5687 6.3429 0.0000 0.6637 2.2698 2.7519

3Q 24.4259 0.5 8.6776 3.0518 11.7294 6.8741 0.0000 0.6204 2.1040 2.5980

4Q 19.1917 0.5 7.8132 2.6732 10.4864 3.9615 0.4413 0.5301 1.5890 1.6834

AVG 20.9981

Table 8-2: Modeled Relative Response Factors (RRFs) – Liberty Annual

QTR

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP)

1Q 0.6281 0.8418 0.9662 1.0609

2Q 0.5840 0.5897 0.8604 1.1010

3Q 0.5911 0.5581 0.8319 1.1148

4Q 0.6750 0.8021 0.9216 1.0777

Table 8-3: Future Projected Quarterly Compositions – Liberty Annual

QTR Total PM2.5 Blank

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP) Ammonium Water

1Q 14.5383 0.5 4.0188 4.2186 1.9081 0.6517 1.9384 1.3027

2Q 13.5201 0.5 5.5883 3.7401 0.0000 0.7307 1.3384 1.6227

3Q 14.5860 0.5 6.9336 3.8365 0.0000 0.6916 1.1743 1.4500

4Q 14.3708 0.5 7.0779 3.1774 0.4067 0.5713 1.2898 1.3477

AVG 14.2538

Table 8-4: Liberty Annual Design Values

Case Year Value

Baseline 2002 21.0

Future Projected 2014 14.3
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 40

A summary of the annual design value calculations for Clairton is given in Tables 8-5 to 8-8. 

Spreadsheets showing the expanded design value calculations are given in Appendix J. All 

compositions and design values are given in μg/m3, while RRFs are dimensionless ratios.

Table 8-5: Baseline Quarterly Compositions – Clairton Annual

QTR Total PM2.5 Blank

Organic 

Mass (by 

Balance)

Elemental

Carbon

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP) Ammonium Water

1Q 13.9271 0.5 3.6998 1.1330 4.8328 3.7848 1.4916 0.4639 1.6751 1.1788

2Q 17.3044 0.5 5.0513 2.3941 7.4453 4.9353 0.0000 0.5164 1.7661 2.1413

3Q 20.9413 0.5 7.4138 2.6073 10.0211 5.8730 0.0000 0.5300 1.7976 2.2196

4Q 14.7063 0.5 5.9382 2.0317 7.9700 3.0109 0.3354 0.4029 1.2077 1.2794

AVG 16.7198

Table 8-6: Modeled Relative Response Factors (RRFs) – Clairton Annual

QTR

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP)

1Q 0.8023 0.8418 0.9662 1.0609

2Q 0.6714 0.5897 0.8604 1.1010

3Q 0.6008 0.5581 0.8319 1.1148

4Q 0.7279 0.8021 0.9216 1.0777

Table 8-7: Future Projected Quarterly Compositions – Clairton Annual

QTR Total PM2.5 Blank

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP) Ammonium Water

1Q 11.9447 0.5 3.8773 3.1862 1.4412 0.4922 1.4640 0.9839

2Q 11.2818 0.5 4.9991 2.9101 0.0000 0.5686 1.0414 1.2626

3Q 12.6319 0.5 6.0211 3.2778 0.0000 0.5909 1.0033 1.2388

4Q 11.4645 0.5 5.8017 2.4149 0.3091 0.4342 0.9803 1.0243

AVG 11.8307

Table 8-8: Clairton Annual Design Values

Case Year Value

Baseline 2002 16.7

Future Projected 2014 11.8
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 41

8.5. 24-Hour Standard (65 μg/m3) Test Results

A summary of the 24-hour design value calculations for Liberty is given in Tables 8-9 to 8-13. 

Spreadsheets showing the expanded design value calculations are given in Appendix J. 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.

Table 8-9: Baseline Quarterly High Days – Liberty 24-Hour

QTR 2000 2001 2002 2003 2004

1Q 46.7 61.9 50.8 60.4 64.2

2Q 64.2 63.9 58.2 66.6 59.6

3Q 48.6 56.4 59.9 60.8 64.2

4Q 60.3 57.5 56.8 64.8 68.5

Table 8-10: Baseline Quarterly Compositions – Liberty 24-Hour

QTR Total PM2.5 Blank

Organic 

Mass (by 

Balance)

Elemental

Carbon

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP) Ammonium Water

1Q 23.7667 0.5 7.8059 3.0633 10.8692 5.5200 1.7867 0.7400 2.5881 1.7627

2Q 48.8000 0.5 14.5477 7.4633 22.0110 14.0533 0.0000 1.0367 5.2700 5.9290

3Q 42.6333 0.5 17.5372 6.1533 23.6905 10.1200 0.0000 0.7300 3.3396 4.2532

4Q 43.0833 0.5 21.5537 7.2700 28.8237 6.8633 0.3217 1.0167 2.6670 2.8910

(Note: Total carbon is the total of organic carbon and elemental carbon.)

Table 8-11: Modeled Relative Response Factors (RRFs) – Liberty 24-Hour

QTR

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP)

1Q 0.5451 0.8408 1.1309 1.1286

2Q 0.5046 0.4952 1.6330 1.1917

3Q 0.5233 0.5233 1.1323 1.1282

4Q 0.5597 0.6503 1.1297 1.1675

Table 8-12: Future Projected Quarterly High Days – Liberty 24-Hour

QTR 2000 2001 2002 2003 2004

1Q 34.2 45.3 37.2 44.2 47.0

2Q 33.2 33.1 30.1 34.5 30.9

3Q 25.8 29.9 31.7 32.2 34.0

4Q 36.7 35.0 34.6 39.5 41.7

Table 8-13: Liberty 24-Hour Design Values

Case Value

Baseline 64

Future Projected 42
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 42

A summary of the 24-hour design value calculations for Clairton is given in Tables 8-14 to 8-18. 

Spreadsheets showing the expanded design value calculations are given in Appendix J. All 

compositions and design values are given in μg/m3, while RRFs are dimensionless ratios.

Table 8-14: Baseline Quarterly High Days – Clairton 24-Hour

QTR 2000 2001 2002 2003 2004

1Q --- 22.9 20.2 24.1 16.7

2Q --- 44.5 50.4 58.8 26.3

3Q --- 36.5 39.8 37.0 39.8

4Q --- 31.5 35.0 21.1 26.4

Table 8-15: Baseline Quarterly Compositions – Liberty 24-Hour (by percentage, applied to Clairton 

high days)

QTR Total PM2.5 Blank

Organic 

Mass (by 

Balance)

Elemental

Carbon

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP) Ammonium Water

1Q 23.7667 0.5 7.8059 3.0633 10.8692 5.5200 1.7867 0.7400 2.5881 1.7627

2Q 48.8000 0.5 14.5477 7.4633 22.0110 14.0533 0.0000 1.0367 5.2700 5.9290

3Q 42.6333 0.5 17.5372 6.1533 23.6905 10.1200 0.0000 0.7300 3.3396 4.2532

4Q 43.0833 0.5 21.5537 7.2700 28.8237 6.8633 0.3217 1.0167 2.6670 2.8910

(Note: Total carbon is the total of organic carbon and elemental carbon.)

Table 8-16: Modeled Relative Response Factors (RRFs) – Clairton 24-Hour

QTR

Total 

Carbon Sulfate Nitrate

Crustal 

(OPP)

1Q 0.7555 0.8018 1.0187 1.0702

2Q 0.5555 0.5198 1.0447 1.1634

3Q 0.5147 0.5641 0.9517 1.1445

4Q 0.6292 0.5828 1.0972 1.0999

Table 8-17: Future Projected Quarterly High Days – Clairton 24-Hour

QTR 2000 2001 2002 2003 2004

1Q --- 18.4 16.3 19.4 13.5

2Q --- 24.7 27.9 32.5 14.7

3Q --- 19.8 21.6 20.1 21.6

4Q --- 20.1 22.3 13.5 16.9

Table 8-18: Clairton 24-Hour Design Values

Case Value

Baseline 49

Future Projected 27
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 43

8.6. Lincoln 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.6 The 

Liberty and Clairton Monitors are part of a complete network for Allegheny County – according 

to monitoring network guidance, there are no “unmonitored” areas. However, for a more 

complete analysis, ACHD examined all locations between the Liberty monitor site and the U. S. 

Steel Clairton Plant, referred to as the “Lincoln area”, which comprises portions of Lincoln, 

Liberty, and Glassport.

The Lincoln area corresponds to the area downwind from the Clairton plant, since wind is 

predominantly from the southwest in the area. A large portion of the area is not suitable as a 

neighborhood-scale location for monitoring PM2.5 because it does not represent a highly 

populated area and is source-oriented, i.e., within an “area of influence” of the Clairton plant.

Monitored data since 1999 has shown that Liberty considerably exceeds monitored data in 

surrounding areas (including Clairton, North Braddock, Forward, and South Park) on both 

annual and 24-hour bases. Table 8-19 below shows the projected design values for Liberty, 

Clairton, and North Braddock (the nearest current PM2.5 site outside the Liberty-Clairton area). 

All monitors are below the standards in the future case.

Table 8-19: Future Case Design Values

Site Annual 24-Hour

Liberty 14.3 42

Clairton 11.8 27

North Braddock* 14.3 33

 * North Braddock values are taken from the Pittsburgh-Beaver Valley SIP

Any flat-terrain interpolation from Liberty to other areas would show a decreasing concentration 

gradient. In the case of the Liberty-Clairton area, terrain and meteorology can strongly affect 

concentrations. Supplemental modeling was performed to examine the specific reductions of 

impacts in the Lincoln area. Modeled contour plots of the PM2.5 impact reductions were 

generated as follows:

Create a receptor grid at 250 meter spacing for a dense grid covering all hills and valleys 

in the Lincoln Area

 

6

The Modeled Attainment Test Software (MATS) was developed by EPA to automatically calculate design values 

and interpolate for unmonitored areas. However, MATS does not recognize terrain and meteorology-driven 

scenarios that affect the Liberty-Clairton Area. Furthermore, testing of MATS version 2.2.1 showed inconsistent 

results with methodology given in the EPA Modeling Guidance. Therefore, MATS was not used in this attainment 

demonstration.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 44

Model all sources in the 20 kilometer domain for baseline and future cases

Plot the percent reduction from the baseline case impacts on an aerial map to examine 

annual and 24-hour high percent reductions throughout the Lincoln area

The receptor grid used for the Lincoln area is given below in Figure 8-1. Receptors are shown as 

the yellow dots at 250 m spacing throughout the Lincoln area.

Figure 8-1: Receptor Grid for the Lincoln Area
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 45

A contour plot of annual impact reductions for the Lincoln Area is shown below in Figure 8-2. 

The contour labels indicate the percent reduction, which is calculated as the baseline minus 

future concentration, divided by baseline concentration (in %). The contours are color-coded 

yellow-to-red, with yellow as the lowest reductions and red as the highest.

Figure 8-2: Annual Impacts by Percent Reduction in Lincoln Area

The attainment test shows that the Liberty site is being reduced from a baseline weighted annual 

concentration of 21.0 μg/m3 to 14.3 μg/m3 due to modeled reductions of 45% (baseline to 

future). While actual monitored concentrations are unknown in the Lincoln Area, the contours 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 46

show percent reductions throughout the Lincoln area that are equal to or greater than the 

reductions at the Liberty monitor site.

Further examination of the annual reductions throughout area is shown in Figure 8-3.

Figure 8-3: Annual Percent Reductions with Descriptions

The largest localized reductions occur near the site of Mon Valley Transportation Center, which 

was shut down in the future modeled case. The widespread reductions throughout the downwind 

area are primarily due to the proposed new configuration at the U. S. Steel Clairton Plant. 

Additional reductions throughout the area can be due to regional decreases in emissions from 

sources outside the Liberty-Clairton area.

Liberty Site

Reductions here due 

to shutdown of Mon 

Valley Transportation 

Center

Reductions throughout 

downwind area primarily 

due to proposed future 

configuration at U. S. Steel 

Clairton Plant

Additional reductions can be 

due to decreases in 

emissions from surrounding 

and background sources

Clairton 

Plant
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 47

A contour plot of 24-hour impact reductions for the Lincoln Area is shown below in Figure 8-4.

Figure 8-4: 24-Hour Impacts by Percent Reduction in Lincoln Area

The attainment test shows that the Liberty site is being reduced from a baseline weighted 

concentration of 64 μg/m3 to 42 μg/m3 due to modeled reductions of 50% (baseline to future). 

Similar to the annual percent reduction contours in Figure 8-2, the 24-hour contours show 

percent reductions throughout the Lincoln area that are equal to or greater than the reductions at 

the Liberty monitor site.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 48

8.7. Model Performance

Model performance for regional CMAQ modeling has been performed by the New York State 

Department of Environmental Conservation (NYSDEC) and is included in Appendix K of this 

SIP. The CMAQ model performance examined prediction for major species throughout the 

modeled Mid-Atlantic/Northeastern U.S. For the Liberty-Clairton demonstration, the combined 

CMAQ/CALPUFF local modeling was examined for appropriateness in predicting the local 

excess component.

ACHD analysis has shown that localized excess in Liberty-Clairton is dependent on nighttime 

temperature inversions within complex terrain.7 The modeled concentrations should therefore 

represent a diurnal trend similar to the monitored data. Plots of average hourly combined

CMAQ/CALPUFF modeled concentrations compared to monitored concentrations (measured by 

the Liberty continuous TEOM) for baseline 2002 are given below in Figures 8-5 and 8-6, by

year-round and quarterly average bases, respectively.

Figure 8-5: Hourly Average Liberty Modeled and Monitored PM2.5 (TEOM), Baseline 2002, 

Year-Round Basis

 

7

Inversion data for 2002 is shown in Appendix A.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 49

Figure 8-6: Hourly Average Liberty Modeled and Monitored PM2.5 (TEOM), Baseline 2002, 

Quarterly Basis

The combined CMAQ/CALPUFF model simulation effectively recognized the diurnal trends in 

hourly data in all four quarters, with the best predicted hourly averages occurring in the 2nd and 

3

rd quarters. Differences in overall concentration show that the model overpredicted for all hours

– however, the modeled concentrations are used for relative reductions from the base to future 

case instead of absolute comparison to the NAAQS.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 50

In order to compare base to future case modeled diurnal trends, average hourly combined 

CMAQ/CALPUFF modeled Liberty concentrations for baseline and future cases are shown 

below in Figures 8-7 and 8-8, by year-round and quarterly bases.

Figure 8-7: Hourly Average Liberty Modeled Baseline and Future Cases, 2002 and 2014, YearRound Basis
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 51

Figure 8-8: Hourly Average Liberty Modeled Baseline and Future Cases, 2002 and 2014, 

Quarterly Basis

The before and after model results show that the future case controls lower concentrations 

overall, with the largest reductions occurring during the nighttime inversion periods (indicated 

by the longer dotted high-low lines) in all four quarters. These plots demonstrate that the 

modeled response to the future control measures is effectively reducing the local excess that has 

been observed in hourly monitored data.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 52

Combined CMAQ/CALPUFF modeled results were also compared on a daily basis to the FRM 

results from 2002. Modeled daily averages and FRM values for Liberty in 2002 are shown 

below in Figure 8-9 on a time-scale basis.

Figure 8-9: Daily Average Liberty Modeled and Monitored (FRM), Baseline 2002

Daily comparisons show that the modeled and monitored high days do not show an exact 

correlation, but similar high and low days do occur within each quarter (separated by the dotted 

lines). The long-term design value is based on quarterly reductions from each quarter, and the 

24-hour design value is based on quarterly high day reductions. Therefore, the modeled 

concentrations are adequate for projecting relative reductions of monitored results on a quarterly 

basis.

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 on the following page.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 53

Mean Fractional Bias (%)

Mean Fractional Error (%)

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

monitored data for the 2002 baseline case. “Goal” represents a good statistical relationship, 

while “criteria” represents average results (limits were used in regional model evaluations, given 

in the EPA Modeling Guidance). Comparison was done for total PM2.5, since actual monitored 

results from the speciation monitor were not available for 2002.

Table 8-20: Statistics for the Modeled Daily Liberty Averages Compared to the Liberty 

FRM Values, Year-Round and by Season, 2002

DAILY Results

Mean 

Fractional 

Bias

(MFB)

Mean 

Fractional 

Error

(MFE)

1

st Quarter 35.99% 45.76%

2

nd Quarter 7.59% 39.56%

3

rd Quarter 12.25% 30.52%

4

th Quarter 45.91% 51.13%

Year-Round 25.43% 41.73%

GOAL ≤ ± 30% ≤ 50%

CRITERIA ≤ ± 60% ≤ 75%

Positive bias indicates that the model over-predicted for all seasons, with the 2nd and 3rd quarters 

performing the best (lowest) for bias and error. Year-round, 2nd quarter, and 3rd quarter statistics 

fell within the goal range, indicative of good results. 1st and 4th quarter results fell within the 

criteria range, indicative of average results.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 54

Figure 8-10 shows a “soccer plot” that visually shows the daily statistics as data points within the 

goal and criteria ranges (red and blue boxes, respectively). Year-round, 2nd quarter, and 3rd

quarter points lie within the “goal” of the soccer plot.

Figure 8-10: Liberty Daily Model Statistics, Baseline 2002
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 55

Figures 8-11 and 8-12 show correlation plots with linear regression statistics for year-round and 

seasonal combined CMAQ/CALPUFF Liberty daily modeled and monitored FRM results. The 

dotted red 1:1 lines represent perfect correlation.

Figure 8-11: Liberty Modeled and Monitored Correlation, Daily Averages, Baseline Case 2002, 

Year-Round Basis
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 56

Figure 8-12: Liberty Modeled and Monitored Correlation, Daily Averages, Baseline Case 2002, 

Quarterly Basis
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 57

Similar to bias and error results, 1st and 4th quarter data (along with year-round) showed the best 

correlation between daily modeled and monitored results.

Table 8-21: Statistics for the Modeled Hourly Liberty Values Compared to Liberty TEOM 

Values, Year-Round and by Season, 2002

HOURLY Results

Mean 

Fractional 

Bias

(MFB)

Mean 

Fractional 

Error

(MFE)

1

st Quarter 44.74% 69.56%

2

nd Quarter 4.90% 52.85%

3

rd Quarter 16.66% 48.80%

4

th Quarter 43.35% 83.61%

Year-Round 28.62% 63.69%

GOAL ≤ ± 30% ≤ 50%

CRITERIA ≤ ± 60% ≤ 75%

The hourly statistics show shows that the model was less accurate on an hourly basis than a daily 

basis, but the hourly results do achieve goal for bias and criteria for error on a year-round basis. 

Seasonal results also show similar trends to the daily results, with 2nd and 3rd quarters producing 

the best statistics and 1st and 4th quarters producing the worst statistics.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 58

9. Reasonably Available Control Technology and Measures

The requirements for 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 and to 

meet any RFP requirements. 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. 

Primary PM2.5 is the pollutant of concern in the Liberty-Clairton nonattainment area. As 

presented earlier in this SIP, the area is too small, and conditions are not appropriate for SO2 or 

NOx from sources located within the nonattainment area to be able to convert to PM2.5. So 

RACM, including RACT, was reviewed for primary PM2.5 only. 

Most of the emission reductions to reach attainment are dependent on the construction of new 

low emission quench towers at the U. S. Steel Clairton Plant. The new quench towers will result 

in a decrease of over 700 tons per year of primary PM2.5. The batteries and quench towers have 

already engaged reasonably available control technology, and the entire five-municipal LibertyClairton region, beyond the batteries and quench towers, total less than 200 tons per year of 

primary PM2.5. No combination of further controls in addition to those already imposed on the 

area would advance the attainment date by one year. ACHD has, therefore, adopted RACT and 

RACM as defined for this PM2.5 SIP.

There are two stationary major sources: U. S. Steel Clairton Plant and Koppers Industries. MidContinent Coal and Coke Company was listed as a major source in 2000-2002 and is included 

here but has since been classified as a minor source. All three sources are required to have 

operating permits. There are seven other stationary minor sources required to have operating 

permits in the same area. A unit-by-unit analysis of all the RACT for the Liberty-Clairton area 

PM2.5 is found in Appendix B.

The sole purpose of this RACT/RACM analysis is for determining whether there were additional 

reasonable controls 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. 

A. RACT at U. S. Steel Clairton Plant and Alternatives Considered

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. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 59

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. 

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 

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.

B. RACT at Koppers Industries, Inc. and Alternatives Considered

Koppers Industries, Inc.’s 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. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 60

C. 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 April 2011 Page 61

10. Reasonable Further Progress

This section explains and demonstrates reasonable further progress (RFP) by achieving 

incremental emission reductions required until the area known as the Liberty-Clairton 

nonattainment area in Allegheny County reaches attainment of the federal PM2.5 air quality 

standard. The data in this section is based on information that has been provided in other sections 

and appendices of this plan.

10.1. Reasonable Further Progress Requirements

The Clean Air Act (Act) requires attainment plans to meet RFP by achieving incremental 

emission reductions to ensure attainment of National Ambient Air Quality Standards (NAAQS) 

by the attainment date (Section 171(1)). The Act does not identify specific emission reduction 

benchmarks that must be met for PM attainment plans. 

EPA’s interpretation of the Act’s RFP requirement in the Implementation Rule for the PM2.5

NAAQS identifies the concept of achieving generally linear progress (72 FR 20633). According 

to 40 CFR 51 Subpart Z, Section 51.1000 (Definitions):

The RFP benchmark plan is the RFP plan that shows generally linear progress from the 

baseline emissions year through the milestone inventory years.

The baseline year inventory for RFP is the inventory for the year used as the base year 

for the attainment demonstration (for this plan, the baseline year inventory is 2002).

Milestone year inventories occur in 2009 and 2012.

Full implementation inventory is the level of emissions that demonstrates attainment. In 

the Liberty-Clairton nonattainment area the full implementation inventory is 2014.

Determination of RFP milestones involves several steps:

1. Determining the total reductions that must be achieved to reach attainment. The Plan

satisfies this in Section 7, Modeling Procedures.

2. Determine the attainment year that is as expeditious as practicable. This plan 

identifies 2014 as the most expeditious attainment date practicable in the LibertyClairton nonattainment area.

3. Determining the fraction of reductions that are achieved in each milestone year.

The Implementation Rule recognizes that the attainment demonstration will identify the 

pollutants to be included in the RFP demonstration, the relative reductions needed for each of 

these pollutants, and the attainment year.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 62

10.2. Reasonable Further Progress Calculations

Tables 10-1, 10-2, and 10-3 show benchmark calculations specified in EPA’s Implementation 

Rule.

Table 10-1: Emissions Inventory Adjusted for Plan Control Strategy (in Tons per Year)

Description 2002 2009 2012 2014

Direct PM2.5 Inventory After Plan Control Strategy 2,270.6 1,968.8 1,849.9 1,392.6

NOx Inventory After Plan Control Strategy 229,571.7 120,414.1 108,565.5 108,565.5

SO2 Inventory After Plan Control Strategy 587,201.4 141,772.8 132,598.7 132,598.7

NOTES:

 Direct PM2.5 inventories are based on the Liberty-Clairton area only. They include direct PM2.5 emissions 

from point, area, nonroad, and mobile sources.

 NOx and SO2 precursor inventories include point sources that were modeled within the 150 km PM2.5

modeling domain described in Section 7, but limited to Pennsylvania sources outside the Liberty-Clairton 

area in accordance with guidance provided in 72 FR 20636. Precursor inventories also include area, 

nonroad, and mobile sources within the Pittsburgh-Beaver Valley area only.

 Regional control measures (CM) are already incorporated into the MANE-VU regional inventories.

 2012 emissions for uncorrected sources are assumed to be representative through 2014. See Section 7.

Table 10-2: Determining Benchmark Milestones as Tons per Year of Reductions

(Calculations described in footnotes)

Column 

No.

2 3 4 5 6 7 8 9

Pollutant

2002

Emissions 

Inventory1

Attainment 

Benchmark 

(tons/year)

Number of 

tons to be 

reduced3

Tons to be 

reduced by 

2009 

(relative to 

2002)4

2009 EI 

Benchmark

(tons/year)

5

Tons to be 

reduced by 

2012 

(relative to 

2002)6

2012 EI 

Benchmark, 

(tons/year)

7

2014 EI 

Benchmark

(tons/year)

8

Direct 

PM2.5

2,270.6 1,392.6 878.0 512.2 1,758.4 731.7 1,538.9 1,392.6

NOx 229,571.7 108,565.5 121,006.2 70,586.9 158,984.8 100,838.5 128,733.2 108,565.5

SO2 587,201.4 132,598.7 454,602.7 265,184.9 322,016.5 378,835.9 208,365.5 132,598.7

1 Column 2 shows the baseline inventories from Appendices F and H (Local ACHD and MANEVU Regional inventories)

2 Column 3 comes from Table 10-1, which shows that the 2014 inventory with plan controls that 

will bring the Liberty-Clairton area into attainment.

3 Column 4 = Column 2 – Column 3

4 Column 5 = 7/12 of Column 4;

5 Column 6 = Column 2 – Column 5

6 Column 7 = 10/12 of Column 4;
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 63

7 Column 8 = Column 2 – Column 7

8 Column 9 = Column 3

Table 10-3: Comparison of 2009 and 2012 RFP Benchmarks and Projected Levels

Year

Direct PM2.5 NOx SO2

Benchmark1Projected

Level2

Benchmark1Projected

Level2

Benchmark1Projected

Level2

2009 1,758.4 1,968.8 158,984.8 120,414.1 322,016.5 141,772.8

2012 1,538.9 1,849.9 128,733.2 108,565.5 208,365.5 132,598.7

1

From Table 10-2, Columns 6 and 8

2

From Table 10-1, shaded cells

As discussed earlier, EPA’s Implementation Rule specifies that generally linear progress should 

be achieved and that emissions in the milestone years should be at levels that are roughly 

equivalent to the benchmark emission levels. The 2009 and 2012 projected levels shown in 

Table 10-3 are the milestone year emission levels for RFP. Table 10-4 presents calculations that 

demonstrate that the emission reductions achieved meet the RFP requirements. Cumulative 

emission reductions are the reductions achieved from the 2002 baseline emissions; they include 

the reductions in emissions of all three pollutants from the local control measures in the plan, as 

well as reductions in NOx and SO2 emissions from regional control programs. Note: PM2.5

reductions from the shutdown of Batteries 7-9 began in April 2009. The RFP reductions used for 

2009 PM2.5 values were estimated as 71% of the total eventual reductions achieved by 2012.

Table 10-4: Fraction of Reductions Achieved in Each Milestone Year

Milestone 

Year

Emissions

(tons/year)

Cumulative 

Emission

Reductions 

(tons/year)

Percent of Emission 

Reductions Needed 

for Attainment

Percent

Per Year

PM2.5

2002 2,270.6 - - -

2009 1,968.8 301.8 34 1.9

2012 1,849.9 420.7 48 1.9

2014 1,392.6 878.0 100 3.2

NOx

2002 229,571.7 - - -

2009 120,414.1 109,157.6 90 7

2012 108,565.5 121,006.2 100 5

2014 108,565.5 121,006.2 100 4

SO2

2002 587,201.4 - - -

2009 141,772.8 445,428.6 98 11

2012 132,598.7 454,602.7 100 8

2014 132,598.7 454,602.7 100 6
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 64

As shown in the Table 10-4, the PM2.5 plan meets RFP requirements, with continuous and 

generally steady progress towards attainment by achieving between 1.9% to 3.2% emissions 

reductions per year of direct PM2.5. Emissions from NOx and SO2 in both milestone years are 

below the attainment level. In terms of cumulative progress towards attainment, there is steady 

progress for NOx and SO2 pollutant as shown in Table 10-4, so that 100% of the necessary 

reductions are achieved by the attainment date.

With respect to direct PM2.5, reductions will be achieved in the Liberty-Clairton by the end of 

2009 and 2012, ensuring continuous progress towards attainment in year 2014. Attainment 

requires a sizable magnitude of reductions from the Liberty-Clairton area’s major stationary 

source.

Due to the significant nature of the new measures anticipated to be put into effect by the area’s 

major industrial source and the technical complexities of implementation, the final increment of 

the emission reductions needed for attainment, will not occur until the end of 2013.

In summary:

Reductions in direct PM2.5 and precursor emissions are being achieved as quickly as 

possible; 

There is a downward trend in emissions of direct PM2.5 between 2009 and 2014 at a rate 

of 1.9% to 3.2% per year; 

The Liberty-Clairton area will reach attainment as expeditiously as practicable.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 65

11. Contingency Measures

According to the Federal Register, Vol. 72, No. 79, Pages 20642-3, PM2.5 contingency measures 

are additional control measures to be implemented in the event that an area fails to meet RFP or 

fails to attain the standards by its attainment date. 

The Liberty-Clairton area was designated nonattainment in 2005. This attainment demonstration 

is based on an attainment date of 2015. Contingency measures are recommended to be based on 

approximately one year of additional emissions reduction. The emissions reductions anticipated 

by the contingency measures should be equal to approximately 1 year’s worth of emissions 

reductions necessary to achieve RFP for the area.

Table 11-1: Calculation of Required and Excess Emission Reductions

Liberty-Clairton Area PM2.5 (tons/year)

Baseline (2002) Liberty-Clairton Area 

Emissions 2270.6

Projected (2014) Liberty-Clairton Area 

Emissions 1392.6

Change in Emissions 878.0

Target Reductions for Contingency 

Measures (1/10)

87.8

11.1. Indentified Contingency Measures to be Implemented 

The Federal Register, Vol. 72, No. 79, Pages 20642-3 says 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 reasonable further progress (RFP) not be met by 2009 or 2012, or should attainment not 

be achieved by 2015, the consent order and agreement with U. S. Steel (as amended in 

September 2010) specifies the following: within 30 months after receiving notice from ACHD 

that EPA is requiring implementation of the contingency measures, U. S. Steel’s Clairton Plant 

will cease operation of the current Quench Tower 1 as the primary quench tower for Batteries 1-

3 or implement emission reductions greater than or equal to 90 tons per year (unless a lesser 

amount is needed to demonstrate attainment of the annual PM2.5 NAAQS). The use of a low 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 66

emission quench tower in place of the current Quench Tower 1 would lead to a reduction of 173 

tons per year of primary PM2.5, as given in Table 11-2.

Additionally, the consent order and agreement included coke oven wall rebuilds for Battery 20 to 

be implemented in late 2014. Emissions reduced by the improvements to Battery 20 are

expected to be 9 tons/year. Total emissions reductions from the contingency measures are given 

in Table 11-2.

Table 11-2: Contingency Measures Emission Reductions

Process

PM2.5 2014 

Inventory

Value 

(tons/year)

PM2.5

Contingency

Value 

(tons/year)

PM2.5 Reduction

(Inventory – Contingency) 

Value (tons/year)

New Low Emission Tower

for Batteries 1-3

274.8 102.5 172.3

Battery 20 – Rebuilds, 

Combustion Stack 17.5 9.4 8.1

Battery 20 – Rebuilds,

Door Leaks 2.4 1.3 1.1

Total 294.7 113.2 181.5

The Federal Register states that emissions reductions anticipated by the contingency measures 

should be equal to approximately 1 year’s worth of emissions reductions necessary to achieve 

RFP for the area. The emission reductions given in Table 11-2 satisfy the requirement for 

contingency measures.

Due to the shutdown of Batteries 7-9 at the U. S. Steel Clairton Plant in April 2009, reductions 

required for RFP in 2009 have already been achieved. RFP for 2012 is also projected to be 

achieved due to the shutdown of Batteries 7-9, pending future calculation of 2012 emissions 

inventories.

11.2. Contingency Measures – SO2 and NOx

The Pittsburgh-Beaver PM2.5 nonattainment area is a separate nonattainment area; however, it 

completely encircles the Liberty-Clairton nonattainment area. As discussed in Chapter 3 of this 

SIP, it has been shown that the Liberty-Clairton area PM2.5 due to long-range transport and due 

to SO2 and NOx conversion to nitrates and sulfates are consistent across both regions. The 

control strategy for these pollutants are discussed and presented in the Pittsburgh-Beaver PM2.5

SIP. Contingency measures for these pollutants are similarly presented within that SIP.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 67

The Liberty-Clairton PM2.5 nonattainment area is located entirely within the borders of the 

Pittsburgh-Beaver PM2.5 nonattainment area. The Liberty-Clairton area is so small that sulfur 

dioxide and nitrogen dioxide do not have time to convert to sulfates and nitrates. There is very 

little difference in sulfates and no difference in nitrates measured at Liberty from the monitors in 

the larger nonattainment area. The Pittsburgh-Beaver SIP demonstrates that a modeled excess of 

SO2 and NOx emissions provide for the required contingency measures.

11.3. Additional Contingency Measures

There are a number of control measures or voluntary emission reductions either are already 

implemented or on schedule to be implemented in the near future. EPA guidance encourages 

early implementation of contingency measures to guard against failure either to meet a 

milestone or attain the standard. EPA's guidance on early implementation of control measures 

encourages the early implementation of required control measures and of contingency measures 

as a means of guarding against failures to meet a milestone or to attain.

On October 9, 2008, Governor Rendell signed Senate Bill 295, which became Act 124 of 2008, 

the Diesel-Powered Commercial Motor Vehicle Idling Act (Act 124). Act 124 went into effect 

on February 6, 2009. PA DEP estimates that 50 percent of all long duration idling for Class 8 

trucks will be eliminated in 2010 when the temperature exemption for sleeper truck rest expires. 

Statewide emission reductions are estimated to be 1610 tons, 45 tons, and 30 tons per year for 

NOx, VOC, and PM2.5, respectively. PA DEP and ACHD may also utilize enhanced enforcement 

to obtain additional emission reductions.

State-wide regulations are in development and are anticipated to be adopted in the relatively near 

future for NOx controls for cement kilns, NOx controls for glass furnaces, and PM controls for 

outdoor wood furnaces.

Regulations to reduce VOC emissions are in development, including controls on the manufacture 

and use of adhesives, primers, and sealants and regulations incorporating the Control Techniques 

Guidelines issued by the EPA in 2006, 2007, and 2008.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 68

12. Transportation Conformity

Section 176 of the CAA provides a mechanism by which federally funded or approved highway 

and transit plans, programs, and projects are determined not to produce new air quality 

violations, worsen existing violations, or delay timely attainment of the NAAQS. EPA 

regulations issued to implement transportation conformity provide that motor vehicle emission 

“budgets” establish caps of these emissions that cannot be exceeded by the predicted

transportation system emissions in the future. Transportation agencies in Pennsylvania are 

responsible for making timely transportation conformity determinations. The responsible agency 

in the Pittsburgh Area is the Southwestern Pennsylvania Commission, the designated 

Metropolitan Planning Organization (MPO) under federal transportation planning requirements.

Pennsylvania proposes to establish budgets for highway emissions for direct PM2.5 and NOx in 

order to ensure that transportation emissions do not impede clean air goals in the next decade and 

beyond for the Pittsburgh-Beaver Valley nonattainment area, as well as for the Liberty-Clairton 

nonattainment area. The information in Table III-5, once the EPA approves it for purposes of 

conformity, will establish transportation conformity budgets for the Liberty-Clairton area.

Amendments to the 40 CFR part 93 transportation conformity regulations to address the 1997 

PM2.5 standard were published in the Federal Register on May 6, 2005 (70 FR 24280) to account 

for PM2.5 and its precursors. Section 93.102 requires conformity determinations to be applicable 

to direct emissions of PM2.5 and NOx (unless a determination is made that transportation-related 

emissions are not significant contributors to PM2.5), but to emissions of SOx, VOC, and NH3 only 

if a finding is made that transportation-related emissions of these pollutants are significant 

contributors to PM2.5.

Motor vehicle emissions budget for SOx, VOC, and NH3 are needed only if the state air agency 

director or the EPA Regional Administrator makes a finding that motor vehicle emissions 

budgets must be established in order to attain the NAAQS for PM2.5. Because the reactions that 

form particulate matter from emissions of VOC are complex and highly variable, there is 

considerable uncertainty regarding the contribution of VOC to particulate formation.

Likewise, much uncertainty remains regarding the role of NH3 in particulate formation. The 

Commonwealth of Pennsylvania is not considering VOC or NH3 as PM2.5 precursors for the 

purpose of the attainment plan for the Pittsburgh-Beaver Valley nonattainment area, because of 

the uncertainty surrounding their role in particulate formation. Therefore, this SIP revision is not 

establishing a motor vehicle emission budget for VOC or NH3.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 69

Tables 12-1 and 12-2 below show the annual and daily motor vehicle emission budgets compiled 

by the Southwestern Pennsylvania Commission (SPC) for the Liberty-Clairton area conformity 

determination over the period 2009-2012.8 Budgets for PM2.5 and NOx show decreases over the 

future timeframe on annual and daily bases.

Table 12-1: Annual Motor Vehicle Emission Budgets (Tons/Year)

Year PM2.5 NOx

2009 1.5 72.7

2011 1.4 58.9

2012 1.3 52.4

Table 12-2: Daily Motor Vehicle Emission Budgets (Tons/Day)

Year PM2.5 NOx

2009 0.004 0.180

2011 0.004 0.146

2012 0.004 0.129

Tables 12-1 and 12-2 do not include road dust emissions from paved and unpaved roads, or 

construction-related fugitive dust emissions in the area source inventory, due to the extremely 

small area that Liberty-Clairton encompasses.

 

8 Taken from Air Quality Conformity Determination, Pittsburgh Transportation Management Area, SPC, January 

2009.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 70

Figures 12-1 and 12-2 below show the predicted long-term estimates for annual and daily PM2.5

from the SPC conformity assessment.

Figure 12-1: Conformity Assessment for the Liberty-Clairton Area, Annual PM2.5

Figure 12-2: Conformity Assessment for the Liberty-Clairton Area, Daily PM2.5
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 71

13. Weight of Evidence

The 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.

13.1. Local and Regional Trends

Within the five municipalities that make up the nonattainment area (Clairton, Glassport, Lincoln, 

Port Vue, and Liberty,) there are two PM2.5 monitors, along with six other monitors that gauge 

PM2.5 throughout Allegheny County. Figure 13.1 compares the PM2.5 annual averages of each 

monitor throughout Allegheny County.

Figure 13-1: PM2.5 FRM Annual Averages in Allegheny County, 2000-2009

Since 2005, all sites but Liberty and North Braddock had annual averages below the EPA 

standard. In 2009, all monitors recorded an annual average equal to or below the standard. 

[Note: Moon and North Park sites did not operate in 2008 and were restarted in 2009.] The 
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Design Values (3-year averages) for PM2.5 show a more consistent and level trend toward lower 

concentrations, as seen in Figure 13.2.

Figure 13-2: PM2.5 FRM 3-Year Averages in Allegheny County, 2000-2009

While Liberty remains a clear outlier in comparison to other Allegheny County sites, 

concentrations have been decreasing consistently since the 2005-2007 average.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 73

Figure 13-3: Liberty and Clairton Annual Design Values with Trend Lines

Based on monitored data alone, the linear regression trend lines in Figure 13.3 show declining 

design values of PM2.5 through 2014. These trend lines do not account for any additional 

influences to future emission levels that are discussed in this SIP, such as the shutdown of 

batteries at the U. S. Steel Clairton Plant or diesel particulate-reducing projects in Allegheny 

County. Though not statistically significant

9

, both sites show a marked long-term decline in 

PM2.5 concentrations.

Because of regional transport of particulates, emissions from upwind states also contribute to 

localized exceedances. Reductions in regional emissions like those shown in the Reasonable 

Further Progress section of this SIP will help lower the regional portion of PM2.5 at Liberty and 

Clairton.

 

9 Based on EPA Region III’s R Analysis of Pittsburgh-Beaver Valley and Liberty Clairton PM2.5 Areas, October 

2009
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13.2. Wood Stoves & Wood-Fired Boilers

Wood burning stoves and outdoor hydronic wood boilers are on the rise in Allegheny County, 

which currently does not have any regulations concerning particulate emission controls on stove 

and boilers. Visible emission and odor regulations are in place which can manage wood burning 

stoves and boilers, but there is currently no regulation concerning the efficiency of models. 

EPA-certified wood stoves can reduce particulate emissions 70-80% per unit. EPA-certified 

boilers, which burn cleaner than non-certified boilers, also reduce emissions. Many states, 

regions, and municipalities have begun looking into wood-stove and wood-boiler regulations to 

cut down on particulate pollution. Pennsylvania finalized its wood boiler rule on October 2, 

2010, requiring the use of EPA-certified Phase 2 boilers in the state of Pennsylvania. ACHD has 

participated in EPA’s Wood Stove Changeout Campaign, replacing 176 older woodstoves in 

Southwest Pennsylvania with newer, cleaner units. According to EPA10, changing out 20 wood 

stoves results in a net reduction of 1 ton of particulate pollution. An awareness campaign to 

inform municipalities of pollution from wood stoves and boilers is underway by ACHD. 

Receptor modeling showed that vegetative burning is a contributor of PM2.5 at Liberty. The

source apportionment results using the Positive Matrix Factorization Model (PMF Version 1.1)

can be found in Appendix E.

Further work in this area, including local regulations against wood-burning stoves and boilers, 

will reduce particulate pollution further in the nonattainment zones.

13.3. National Regulations – CAIR and TR

The 2005 Clean Air Interstate Rule (CAIR) was used in the MANE-VU regional modeling and 

projected that each participating state would have a 60% reduction of NOx (based on 2003 

levels) and a 70% reduction of SO2 over the course of 10 years. EPA listed Allegheny County as 

one of the nonattainment regions for particulates that would receive the greatest benefit in 

particulate reduction from CAIR. Surrounding states that contribute to regional trends, such as 

Ohio and West Virginia, were also covered by CAIR, which would help reduce regional 

particulate pollution that may be from a source outside Allegheny County. 

CAIR was remanded to EPA in December, 2008. EPA has proposed the Transport Rule (TR) as 

a replacement rule to CAIR, to be effective in 2011. The Transport Rule is expected to be as 

strict as or stricter than CAIR. For a quantitative analysis, SO2 and NOx emissions from the 

2012 CAIR inventory (used in the regional modeling for this SIP) were compared to emissions

used for the proposed Transport Rule 2014 control case (as of October 2010). Emission totals 

for power plants (EGUs) in the 150 km modeling domain used for this SIP are given in Table 

13.1.

 

10 http://www.epa.gov/burnwise/index.html
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Table 13-1: Future Case CAIR and TR Emissions 

Plant Name

SO2 CAIR 

2012 (tons)

SO2 TR 

2014 (tons)

NOx CAIR 

2012 (tons)

NOx TR 

2014 (tons)

Cardinal 14045 14006 3668 2484

R E Burger 4062 5761 3078 3712

W H Sammis 24541 21550 8466 7750

Beaver Valley 3750 1626 4544 2290

Armstrong 13313 2822 2627 3779

Bruce Mansfield 18000 23101 4396 5455

Cheswick 4876 4527 1170 1246

Elrama 4595 4059 5847 6647

Hatfield's Ferry 23194 14507 6487 15412

Homer City 9925 12182 4032 3936

Keystone 10363 13055 2713 2603

Mitchell (PA) 1527 649 3204 2844

New Castle 15062 8988 3555 2888

Fort Martin 49567 7135 10858 7755

Kammer 28490 5188 14245 1353

Mitchell (WV) 15467 19956 3867 3368

TOTAL 240778 159112 82756 73522

DIFFERENCE

(CAIR minus TR) 81666 9234

Emissions in Table 13.1 show that the 2012 CAIR case included 90900 more tons of SO2 and 

NOx emissions than those in the proposed TR 2014 case. This indicates that modeled emissions 

from the tri-state EGUs were a conservative estimate of future modeled impacts.

For a qualitative analysis, committed SO2 and NOx control schedules used for the Transport Rule 

and progress updates for the tri-state EGUs are shown in Table 13.2.
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Table 13-2: EGU Control Implementation Schedule and Progress

Plant Name

Committed SO2 

TR Controls

Committed NOx 

TR Controls Progress (as of February 2011)

Cardinal FGD by 2010-2012 SCR before 2009 FGD installed on Units 1-2, Unit 3 underway

R E Burger FGD by 2010-2011 SNCR before 2009 Units 4-5 shutdown in Dec. 2010 (no conversion to biomass)

W H Sammis FGD by 2010-2011 SCR by 2012 FGD and SCR completed in Dec. 2010

Beaver Valley --- SNCR before 2009 N/A

Armstrong --- SNCR before 2009 N/A

Bruce Mansfield --- SCR before 2009 N/A

Cheswick FGD by 2010-2011 SCR before 2009 FGD completed in 2009

Elrama --- SNCR before 2009 N/A

Hatfield's Ferry FGD by 2009 SNCR before 2009 FGD completed in Oct. 2009

Homer City FGD by 2012 SCR before 2009 Unknown

Keystone FGD by 2009 SCR before 2009 FGD completed in 2009

Mitchell (PA) --- --- N/A

New Castle --- SNCR before 2009 N/A

Fort Martin FGD by 2012 SNCR before 2009 FGD completed in Feb. 2010

Kammer --- SCR by 2012 Unknown

Mitchell (WV) --- SCR before 2009 N/A

Table 13.2 shows that the committed dates fall before the attainment year of 2014 used in this 

SIP and that most controls have been implemented ahead of schedule. Progress for Homer City 

and Kammer controls are unknown at the time of this SIP. Additionally, R E Burger has agreed 

to shut down its Units 4-5, in place of the proposed conversion to biomass.

13.4. Diesel Campaign

In addition to other strategies, ACHD has also been working to encourage diesel fuel engine 

retrofits on local school buses and municipal vehicles. The approximately 2,000 school buses in 

Allegheny County emit a total of about 12 tons of particulate matter, in addition to 370 tons of 

hydrocarbons. 

Allegheny County offers 100% reimbursement grants for school bus retrofits to districts at which 

at least 40% of the students are eligible for free or reduced-cost lunches (based on income) and 

75% reimbursement for all other districts. The utilization of diesel retrofits will allow the 

participating municipalities to reduce toxic diesel emissions 30-90%, depending on the type of 

retrofit chosen.

Currently a contractor that serves the Pittsburgh Public Schools has requested $450,000 for 37

school bus retrofits. In addition, the school districts within the Liberty-Clairton nonattainment
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 77

area are all eligible for the program, and the five townships that make up the area are currently 

working on a diesel retrofit project along with ACHD and the Allegheny County Partnership to 

Reduce Diesel Pollution.

The project will provide diesel retrofits to municipal vehicles in these townships and is currently 

underway. A Clean Air Fund grant of $200,000 has been allocated for the purpose of the project, 

and ACHD and the Diesel Partnership are working with the local governments to install retrofits 

on municipal vehicles.

Anti-idling regulations for school buses have been in effect since late 2004 in Allegheny County. 

School buses are not allowed to idle for longer than 5 minutes, unless actively picking up or 

discharging students. The regulation also restricts idling near school air intakes. Lowered idling 

times of buses reduces diesel consumption and diesel emissions. 

Anti-idling regulations for trucks and transit buses have been in effect since 2005. Drivers of 

diesel engine vehicles can be reported to ACHD and can be fined up to $500 if they are found to 

idle unnecessarily for more than 5 minutes in a one-hour period.

In addition, Pennsylvania recently adopted a state-wide ban on unnecessary diesel idling. 

Outreach and public education for these new regulations are currently underway.

Emission reductions due to school bus and municipal vehicle retrofits and the anti-idling 

regulations are not factored into the modeled data of this SIP, and represent additional reduction 

strategies that are ongoing within Allegheny County and the Liberty-Clairton nonattainment

area. 

13.5. State and Competitive ARRA Clean Diesel Grants

The Allegheny County Health Department, with input from Group Against Smog and Pollution 

(GASP) and Clean Water Action, 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 will be 

distributed among five partners in a project that is scheduled during the 2009-2010 timeframe. 

The projects will help reduce diesel pollution in Pittsburgh, the Liberty-Clairton nonattainment

area, and throughout Southwestern PA. The money comes from the American Recovery and 

Reinvestment Act (ARRA) and the National Clean Diesel Program. These projects will take 

place over the following year, and will be completed by September 2011.

The Port Authority of Allegheny County will use ARRA funds to assist in replacing two 1996-

model transit buses with 2010-model cleaner diesel hybrid electric buses and to repower nine 

2003-model diesel buses with engines that meet the new, higher 2007 emission standards. This 

will reduce particulate matter pollution by approximately 0.1 tons per year, carbon monoxide by 

2.8 tons per year, and nitrogen oxides by 6.8 tons per year.

Constructors Association of Western Pennsylvania will use ARRA funds for retrofit technologies 

– engine repowers, upgrades and diesel particulate filters – to upgrade 42 diesel-powered, heavy 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 78

non-road construction equipment in Western Pennsylvania. The various upgrades will reduce 

particulate matter pollution by 1.8 tons per year, carbon monoxide by 14.6 tons per year, 

hydrocarbons by 2.09 tons per year, and nitrogen oxides by 9.73 tons per year. 

Harsco Metals North America provides trucking for U. S. Steel. With ARRA funds they will 

install diesel particulate filters on 11 dump trucks operating in and around U. S. Steel's Mon 

Valley Works. Once upgraded, these dump trucks will be 90-percent less polluting than they are 

today. It is estimated that these diesel particulate filters will remove 0.06 tons of particulate 

matter per year, 0.20 tons of carbon monoxide per year, and 0.91 tons of hydrocarbons per year. 

With ARRA funds CSX Transportation will 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 will operate at CSX's 

McKeesport/Demmler rail yard, bringing immediate air quality benefits to the residential 

neighborhood nearby. The project will cut 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 will 

also save 15,000 gallons of diesel fuel annually and provide quieter operation for the nearby 

residents of McKeesport.

The Allegheny County Health Department will also receive $433,100 to equip diesel-powered

municipal waste haulers with diesel particulate filters. The money comes from the ARRA via 

the State Allocation Grant Program. A previous project led by GASP and Clean Water Action 

installed diesel particulate filters on 13 waste haulers in the city, reducing diesel particulate 

pollution from each vehicle. This new funding will help ACHD, GASP, and Clean Water Action 

complete the project by retrofitting 33 of the remaining city vehicles.

Because of the frequent starting and stopping of the vehicles, and the proximity to all 

neighborhoods and families in the city, this project will significantly help local air quality. The 

project will take place from July 2009 through August 2010, by when all vehicles are scheduled 

to be retrofitted.

These projects are additional PM2.5 reduction strategies outside of the modeled data within this 

SIP. 

13.6. 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. According to a University of Pittsburgh study of housing and sociodemographic trends in Allegheny County11, four of the five nonattainment municipalities have 

been in decline for nearly 50 years. In the 1990-2000 period, Clairton has experienced a change 

of -12.1%. Glassport had a decline of -10.6%, Port Vue of -8.9%, and Liberty of -2.7%. Lincoln 

 

11 "Allegheny County Housing and Socio-Demographic Trends," co-author with Christopher Briem and Angela Williams Foster. 

Prepared for the Allgheny Couny Comprehensive Plan, University Center for Social and Urban Research, University of Pittsburgh

and McCormick Taylor, Inc., Pittsburgh, December 2005.
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experienced an increase in population of 1.3%, though this is only from a gain of 15 people 

within the 10 year period. 

Lowering populations signal lower use of cars and a lower need for school buses and other diesel 

engine driven vehicles. Additionally, various consumption activities will decline (power use, 

water use, et cetera,) and lower amounts of waste will be produced. Combining all of this with 

the local regulations such as the school bus idling regulation, and national regulations and trends 

toward more efficient and clean cars and fuels, it is assumed that particulate emissions in the 

nonattainment areas will reach lower levels than the models show.

Figure 13-4: Population Trends for Allegheny County, 1990-2000

{Deitrick, et al., 2005}
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13.7. Monitored Data During Low Production

Economic recession in 2009 led to decreased levels of production at many industrial facilities in 

Southwest PA. 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. Similar to speciation data comparisons, TEOM 

and FRM data from Liberty is compared to that from Lawrenceville 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 13-5 for Liberty and 

Lawrenceville during the period of 2000-2008. Hours are given according to Eastern Standard 

Time (EST).

Figure 13-5: Long-Term Hourly PM2.5 TEOM Averages at Liberty and Lawrenceville, 2000-

2008 

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.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 81

Long-term hourly averages at each site were compared to averages for 2009 data. The Liberty 

long-term averages are shown along with 2009 averages in Figure 13-6 below.

Figure 13-6: 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.

Figure 13-6 is similar to the before-and-after modeled hourly concentrations graph shown in the 

model demonstration discussion (Figure 8-5) in this SIP. This is evidence that controls used in 

the modeling demonstration should show actual results similar to the 2009 low-production 

scenarios.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 82

The Lawrenceville long-term averages are shown along with 2009 averages in Figure 13-7

below.

Figure 13-7: 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.

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.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 83

Table 13-1 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 13-3: 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 2

nd and 3rd quarters in 2009 are significantly smaller than in 

previous years, coinciding with low production levels at local sources.

At the U. S. Clairton Plant, Batteries 13-15 were idled from Mar.-Dec. 2009, along with B 

Battery from Apr.-Jun. 2009, due to recession. Batteries 7-9 were also permanently idled in 

April 2009. At the RRI Energy 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 April 2011 Page 84

To further illustrate the lower localized source influence in 2009 data, a plot of the LibertyLawrenceville TEOM difference is shown in Figure 13-8 for 2009 and previous years. For this 

chart, 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 13-8: 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.
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14. 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.
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15. Legal Documents

15.1. Notice of Public Hearing and Comment Period
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15.2. Transmittals of Hearing Notice to PA DEP and EPA
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15.3. Proof of Publication and Certification of Public Hearing
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Revision 67

SIP Revision for PM2.5 for Liberty-Clairton

Certification of Hearing

Jason Maranche deposes and says that he is an Air Pollution Control Engineer with the Air 

Quality Program of the Allegheny County Health Department and hereby certifies that a Public 

Hearing was held on December 16, 2010 regarding the proposed revision to Allegheny County's 

portion of the State Implementation Plan (SIP) for particulate matter 2.5 microns or less in 

diameter (PM2.5); that the opportunity for written comments was given during the period 

November 15, 2010 through December 16, 2010 in accordance with the requirements of 40 CFR 

51.102; that notice of such hearing was given by publication in a newspaper of general 

circulation on November 12, 2010; and to the best of his knowledge, belief and understanding, 

such proceedings were in full compliance with all applicable state and federal laws, regulations, 

and other requirements.

Jason Maranche

Air Pollution Control Engineer III

Air Quality Program

Allegheny County Health Department

 December 17, 2010

Date
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 92

15.4. Summary of Public Comments and Responses

Comment and Response Document for the Proposed SIP Revision 67

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

Liberty-Clairton PM2.5 Attainment Plan 

December 16, 2010 Public Hearing

Public Comment Period ending December 16, 2010

PROBLEM STATMENT

Comments related to the description of the Liberty-Clairton PM2.5 problem.

1. Comment: The Lawrenceville monitor was used to evaluate and compare regional 

concentrations of PM2.5. ACHD has not adequately explained how it came to this conclusion 

and how this monitor can be used to evaluate regional concentrations of PM2.5. The 

Lawrenceville monitor does not represent background PM2.5 concentrations of Allegheny 

County or the Pittsburgh-Beaver Valley area nor is it representative of conditions in the 

Liberty-Clairton area. 

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: The Lawrenceville site has been used as the urban site for the Pittsburgh-Beaver 

Valley area. Speciation sites within the Pittsburgh-Valley area (excluding Liberty) have been 

shown to measure consistent concentrations for major species. The background site used for 

Pittsburgh-Beaver Valley in EPA’s designation process was Dolly Sods, WV, a rural monitor 

located in a U.S. Wilderness area with lower concentrations than any of the PittsburghBeaver Valley speciation sites. For comparison of regional and localized components of 

PM2.5, the Lawrenceville site was therefore used as the regional site along with Liberty as the 

local site for the Liberty-Clairton area.

2. Comment: ACHD should update its PM2.5 SIP document to include the most recent 

design values. This should also include updating various figures within the SIP document to 

include the most recently available PM2.5 concentrations.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: The SIP has been updated with PM2.5 design values through 2009.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 93

CONTROL STRATEGY

Comments related to the controls used to show projected attainment.

3. Comment: U. S. Steel has concerns over the Department's reliance on emission 

reductions as a result of CAIR as a part of the strategy. If CAIR or other regional reductions 

are not met as outlined in the plan, U. S. Steel would be forced to implement contingency 

measures for which the Department has failed to show how they would enable the area to 

reach attainment.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Reductions projected by the Clean Air Interstate Rule (CAIR) represent the best 

data available for future PM2.5 levels, specifically for sulfates and nitrates. Future 

projections, though not available at this time, are expected to be equal to or better than the 

CAIR reductions. The Pennsylvania CAIR regulation was made final in December 2009, 

and will be in place prior to the SIP attainment date.

4. Comment: EPA's Clean Air Interstate Rule (CAIR) is listed as one of the control 

measures used to demonstrate attainment of the 1997 Fine Particulate Matter (PM2.5) 

National Ambient Air Quality Standards (NAAQS). However, CAIR cannot be used to 

demonstrate attainment of the 1997 PM2.5 NAAQS if an area is requesting an extension of 

the attainment date beyond April 5, 2010.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: The Liberty-Clairton Area cannot reach attainment without precursor emission 

controls at local and distant power plants. The Transport Rule (TR) has been proposed as a 

replacement for CAIR; and controls in the final Transport Rule (to be effective in 2011) will 

be similar to those with CAIR. SO2 and NOx emissions used in the proposed Transport Rule 

(as of October 2010) for power plants in the tri-state area were found to be 90900 tons less 

than emissions modeled. Therefore, the modeled emissions using CAIR controls may be 

considered a conservative projection of future case emissions. A comparison of CAIR and 

TR emissions and controls has been added to the weight of evidence section of the SIP.

EMISSIONS INVENTORY

Comments related to the pollutant inventories used for the baseline and projected 

emissions.

5. Comment: ACHD and MANE-VU completed emissions inventory reviews and revisions 

with little or no input from sources other than U. S. Steel's Clairton Works. Since 2002 

source testing and emissions inventory instructions have changed significantly; other than 

source testing at Clairton, ACHD and MANE-VU did not included source testing data from 

any other sources. U. S. Steel is concerned about a possible unknown “smoking gun" source 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 94

or a combination of other sources that would cause the area to fail to achieve attainment, 

thereby requiring U. S. Steel to solely implement contingency measures.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Most of the regional controls that will provide the majority of improvement in 

PM2.5 are form the sulfur dioxide and nitrogen oxides sources where emission factors and 

emission rates are well known. Local emission inventories were reviewed against ACHD 

inventories for accuracy. Furthermore, the modeling results indicated that most sources 

outside of the immediate vicinity of the area did not show significant concentration gradients 

in comparison to specific U. S. Steel Clairton sources. Control of sources with small 

concentration gradients would show little or no relative reductions from baseline case to 

future projected case.

6. Comment: When Tables 6-1 and 6-2 are compared, it appears that ACHD anticipates 

emission increases for several pollutants for several types of sources, such as increases of 

PM10 from area sources; increases of SO2 from stationary point sources and area sources 

(which is anticipated to result in a total increase of SO2); increases of NOx from area sources; 

increases of VOCs from stationary point sources; and increases of ammonia from area 

sources and mobile sources. 

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Emissions inventories given in Tables 6-1 and 6-2 are for particulate matter and 

precursors from sources within the Liberty-Clairton area only, and do not include the large 

amount of decreases expected from sources outside the area. The emissions inventory 

section has been revised on Page 20 of the SIP to more clearly indicate the represented area. 

SO2 and NOx emissions from the larger modeled area are presented in Table 10-1.

7. Comment: The original and revised SIPs incorrectly use estimated reductions from 

distant power plants to demonstrate attainment. The original and revised SIPs estimate that 

PM2.5 levels in the Liberty-Clairton area will decrease to some extent as a result of reductions 

in emissions from upwind power plants, even though in the SIP such emissions reductions 

are not shown to be from legally-enforceable measures. Reductions may be included in an 

attainment model only when they are as a result of such enforceable measures. Therefore, 

the original and revised SIPs are underestimating the amount of PM2.5 from upwind sources 

that exists in the air in the Liberty-Clairton area. This underestimation may be exacerbated 

by the fact that emissions reductions from upwind power plants were likely to be attributable 

in significant part to implementation of the Clean Air Interstate Rule. Because that rule was 

vacated by a court decision in 2008, many of the measures that power plants were planning 

to implement in order to comply with the rule have been delayed. Accordingly, the original 

and revised SIP may be underestimating the levels of PM2.5 in Liberty-Clairton from upwind 

sources.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 95

Commenter: John K. Baillie, Senior Attorney, Citizens for Pennsylvania’s Future 

(PennFuture).

Response: The Pennsylvania CAIR rule was approved by EPA December 2009. Other 

states have implemented or are implementing their rules. EPA proposed the Transport Rule

to replace CAIR in 2011. The Department fully expects the controls in the original CAIR or 

better to be implemented by the attainment date. PM2.5 SIP modeling is a demonstration of 

predicted future actual impacts of the control strategy and expected actual emission changes 

in the future. Emissions changes from EGUs include expected permit changes, shutdowns 

and constructions, federal limits, or local limits, and best-estimated future actual operating 

levels and emissions. This follows the implementation guidance. The emission reductions 

are quantified in Appendices F-H; emissions information from sources beyond the northeast 

has been added to Appendix G. 

MODELING PROCEDURES

Comments related to the methodology used for the baseline and projected dispersion 

modeling.

8. Comment: In Section 7.1.1, ACHD states that 2012 was selected in place of 2009 for the 

future to take advantage of regional sulfate/nitrate reductions; however, elsewhere in the 

documents, ACHD indicates that it expects emission increases for these pollutants in 2012. 

U. S. Steel would agree with ACHD's assertion that regional sulfate and nitrate reductions 

would be expected, but U. S. Steel questions the estimates provided in the SIP since they do 

not reflect such reductions.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Sulfate and nitrate components of PM2.5 showed decreases from 2009 to 2012 

based on long-range regional modeling of SO2 and NOx precursors. There are no increases 

of sulfate and nitrate expected during this timeframe. An annual increase of 81.32 tons of 

SO2 as a precursor by 2014 is shown in Table 6-2, but for the Liberty-Clairton area only. 

SO2 as a precursor within the Liberty-Clairton area does not represent upwind SO2 that 

contributes to modeled particulate formation in SW PA.

9. Comment: In Table 7-1, ACHD shows an increase in surrounding counties that could 

impact the Clairton-Liberty Borough area. U. S. Steel questions how these increases were 

determined and questions their accuracy. If these estimates are accurate, U.S. Steel is 

concerned that the increases could cause the area to fail to reach attainment thus requiring 

U.S. Steel to implement contingency measures through no fault of U.S. Steel's. 

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Increases in primary PM2.5 emissions from background non-EGU (electric 

generating unit) industrial sources in surrounding counties are based on growth factors 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 96

developed for the MANE-VU regional modeling effort. These sources do not show a 

significant modeled concentration gradient throughout the Liberty-Clairton area. Increases in 

these surrounding counties represent 354 tons, compared to the overall decrease of 25,912 

tons from the most significant sources: those in Allegheny County, the West Virginia 

panhandle, and EGUs within the modeling domain.

10. Comment: Did ACHD account for stack parameter changes at EGUs that have installed 

flue-gas desulfurization projects in its modeling analysis, for example Allegheny Energy's 

Hatfield's Ferry Power Station? Altered stack configurations at these sites may impact the 

Liberty-Clairton PM-2.5 nonattainment area.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: ACHD accounted for stack parameter changes at EGUs within the modeling 

domain. The revisions are described in Appendix H.

ATTAINMENT DEMONSTRATION

Comments related to the assumptions and methodology used for the design value 

calculations.

11. Comment: In Section 8.1, ACHD lists several assumptions that it used in its attainment 

demonstration. U. S. Steel questions how ACHD assumed that the Liberty speciation data is 

representative of both Liberty and Clairton. This is not consistent with other claims made by 

ACHD. In addition, U. S. Steel questions the logic of this assumption if Clairton Works is 

the main source of PM2.5. U. S. Steel asserts that this assumption is not accurately or 

adequately supported by the information provided in the proposed SIP revisions.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Liberty PM2.5 speciation data was used for the relative composition calculations 

for the Clairton site, which is a few miles away. While the long-term annual concentrations 

are lower at Clairton than at Liberty, it is assumed that high days – specifically during 

variable or calm wind periods – exhibit similar PM2.5 compositions throughout the LibertyClairton area. The use of Liberty species compositions is appropriate for Clairton 

compositions. 

12. Comment: The Clean Air Act requires state implementation plans to meet the air quality 

standard everywhere the public has access, not just the spots where pollution monitors are 

located. ACHD cannot show that the air in the Lincoln Area will meet federal air quality 

standards. It seems counterintuitive that PM2.5 levels will be the same in an area directly 

impacted by the stacks at the Clairton Works as they will be at a monitor further downwind. 

EPA recommends additional pollution controls or placing monitors in the area of concern to 

better characterize the problem. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 97

Commenters: Joseph Osborne, Legal Director, The Group Against Smog and Pollution 

(GASP). John K. Baillie, Senior Attorney, Citizens for Pennsylvania’s Future (PennFuture).

Response: The controlling standard of this SIP is the annual standard, which is a 

community-based standard. Analysis of the entire area will continue. ACHD will consider 

whether additional monitors should be placed in this area upon annual network reviews. 

ATTAINMENT DATE

Comments related to the timeframe of the future projected attainment date and 

adequacy of extensions.

13. Comment: The PM2.5 Implementation Rule requires the state to submit a mid-course 

review by April 2011 for each area that cannot demonstrate attainment by 2014 in lieu of any 

other form of tracking reasonable progress. As a reminder EPA is requiring the state to 

submit a mid-course review, which shall include an updated attainment demonstration as 

well as a review of the implementation status of measures included in the SIP submittal, and 

review of recent air quality data.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: ACHD recognizes the requirement for a mid-course review based on the 

attainment dates. 

14. Comment: ACHD has not justified an extension from the April 5, 2010 attainment 

deadline. The Clean Air Act states that an area may be exempted from that requirement for 

up to five years if there is a demonstration that all local control measures that are reasonably 

available and technically feasible for the area are currently being implemented to bring about 

expeditious attainment of the standard by the alternative attainment date for the area. There 

has been no demonstration that local control measures could not be implemented sooner in 

the Liberty-Clairton area.

Commenter: John K. Baillie, Senior Attorney, Citizens for Pennsylvania’s Future 

(PennFuture).

Response: The attainment plan includes the shutdown and replacement of expensive 

equipment at the U. S. Steel Clairton Coke Works. This is a complicated and extensive 

renovation, and as such, requires adequate time for safe and successful construction. The 

schedules had already been set within the construct of a consent order and agreement. 

15. Comment: The Revised SIP cannot model actual attainment in 2015 based on monitor 

data from 2012, 2013, and 2014. In 2015, EPA will use air quality data from ACHD’s 

monitors in 2012, 2013, and 2014 to determine whether the Liberty-Clairton area has attained 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 98

the annual NAAQS for PM2.5. Because attainment in all parts of the Liberty-Clairton area 

depends on implementation of the control measures at Clairton Works required by the 

amended consent order, and because those measures will not be implemented until the end of 

2013, it appears that area will actually attain the standard.

Commenter: John K. Baillie, Senior Attorney, Citizens for Pennsylvania’s Future 

(PennFuture).

Response: The monitored attainment data will be based on one year of data for 2014, with 

subsequent years used for 3-year periods. This is permissible under EPA regulations. 

REASONABLE FURTHER PROGRESS

Comments related to the analysis used to show reasonable further progress toward 

attainment before the future projected attainment date.

16. Comment: The implementation rule requires the attainment plan to demonstrate that 

emissions will decline in a manner that represents generally linear progress from the 2002 

baseline year to the attainment year. Table 10-4 shows the fraction of reductions achieved in 

each milestone year in order to demonstrate attainment of the 1997 PM2.5 NAAQS. 

However, this section does not show the substitution ratio for PM2.5 and the precursor 

pollutants. This section should include the justification for your choice of substitution ratios. 

In doing so we suggest taking into account the relative proportion of the components 

comprising the total PM2.5 mass at air quality monitors and considering the degree to which 

each PM component may contribute to PM2.5 nonattainment.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: No substitution was used in the Reasonable Further Progress section. Decreases 

are demonstrated separately for each pollutant.

CONTINGENCY MEASURES

Comments related to the additional contingency controls used in case the plan fails to 

demonstrate attainment by the attainment date.

17. Comment: U. S. Steel also respectfully disagrees with ACHD's assertion that “the 

Liberty-Clairton area is so small that sulfur dioxide and nitrogen dioxide do not have time to 

convert sulfates and nitrates. There is very little difference in sulfates and no difference in 

nitrates measured at Liberty from the monitors in the larger nonattainment area.” U. S. Steel 

believes that such a statement does not recognize the complexities associated with inversions 

that occur in the Clairton area.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 99

Response: Monitored data and supporting analyses for the baseline timeframe of 2000-2004 

for this SIP indicated consistent trends for sulfates and nitrates throughout SW PA, with no 

outlying concentration variations at Liberty. If there was sufficient time for local conversion 

of SO2 and NOx to sulfates and nitrates, there would have been sizeable differences in these 

levels compared to the Lawrenceville monitor. The Department will continue to investigate 

the formation of sulfates and nitrates in SW PA in future PM2.5 control plans.

18. Comment: U. S. Steel has concerns about the Department's and State's ability to enforce 

the anti-idling regulations to which both rely on in developing the SIP. U. S. Steel believes 

that the regulatory agencies will need to ensure that they appropriately enforce these 

requirements so that the anticipated reductions are realized.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: Due to the uncertainty of emission reductions expected from enforcing the idling 

law, this was not included in the attainment demonstration, but rather discussed as further 

evidence of expected improvements to air quality. 

19. Comment: The Department should have considered anticipated reductions that would be 

expected from anticipated mercury rules. U. S. Steel believes that the Department has not 

adequately addressed the impacts of such forthcoming regulations. In addition, U. S. Steel 

believes that the Department should recognize the anticipated replacement rule as a 

contingency measure.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: The uncertainty in the specifics of the federal replacement rule and the 

Pennsylvania mercury regulations prevented this from being included in this SIP. Particulate 

improvements from this future rule will be considered in future PM2.5 control plans. 

20. Comment: ACHD calculated the contingency measure for PM2.5 to be 87.8 tons/year. 

However, ACHD failed to quantify the emissions reductions associated with the contingency 

measures identified for 2009, and failed to identify any contingency measures for 2012. For 

areas requesting an extension of the attainment date beyond 2015, contingency measures are 

required for 2009, 2012 and 2015. Also, ACHD has noted that they are reserving the option 

to propose an alternative plan for contingency measures to be made final prior to the 

attainment date. Any changes ACHD makes must be submitted to EPA as a SIP revision.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: Emission reductions sufficient for 2009 and 2012 have already been met with the 

permanent shutdown of Batteries 7-9 and Quench Tower 3 by mid-2009. The SIP has been 

revised to reference the conditions of the consent order and agreement.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 100

TRANSPORTATION CONFORMITY

Comments related to the determination that transportation projects will not impact the 

future attainment.

21. Comment: On page 68, ACHD indicates that much uncertainty remains regarding the 

role of NH3 in particulate formation. While U. S. Steel recognizes the challenges presented 

in determining the impacts of NH3 and its role in the formation of PM2.5 in the area, U. S 

Steel believes that additional investigation in this area could be used to determine other 

potential contingency measures. 

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: The Department will continue to investigate the role of NH3 for future PM2.5

control plans.

WEIGHT OF EVIDENCE

Comments related to the supporting evidence used to show that the Liberty-Clairton 

area shows decreasing trends of PM2.5.

22. Comment: The Department should consider a wood stove and wood-fired boiler 

program considered as a contingency measure. There are ample studies available in which 

quantifiable benefits from various programs are presented.

Commenter: Coleen M. Davis, Senior Environmental Engineer, U. S. Steel Corporation.

Response: The 2005 woodstove exchange program did not have a significant impact on 

emission rates within the Liberty-Clairton area. The Department may consider a more 

extensive woodstove exchange program as a possible control strategy or contingency 

measure in a future SIP. Pennsylvania finalized an outdoor wood boiler regulation on 

October 2, 2010.

23. Comment: ACHD should review EPA's proposed Transport Rule to determine if the 

emission controls and schedules included in the rule would enhance the Liberty-Clairton 

PM2.5 nonattainment area's attainment prospects. A qualitative analysis of the proposed 

Transport Rule could be included in the Weight of Evidence section of the ACHD's SIP 

document.

Commenter: Diana Esher, Director, Air Protection Division, U.S. EPA Region III.

Response: A comparison of EGU controls used in the Transport Rule compared to those 

used for the SIP modeling (CAIR controls) has been added to the weight of evidence section. 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 101

Controls used in the proposed Transport Rule were found to be similar to or better than the 

modeled controls.

GENERAL

Comments related to the PM2.5 SIP in general.

24. Comment: The emissions projections for the Clairton Works’ quench towers do not 

account for PM2.5 pollution caused by increasing levels of total dissolved solids in the 

Monongahela River. Solids dissolved in the river water may be emitted from the quench 

towers as PM2.5. The river has experienced increased levels of total dissolved solids in the 

past several years, likely leading to increased PM2.5 emissions from the quench towers, yet 

the original and revised SIPs assume that the water used in the quench towers is not impacted 

by high levels of total dissolved solids. ACHD and U.S. Steel should consider pre-treating 

the river water used by the quench towers to remove excess total dissolved solids and further 

reduce Clairton Work’s PM2.5 emissions.

Commenter: John K. Baillie, Senior Attorney, and Tiffany Hickman, Western PA Outreach 

Coordinator, Citizens for Pennsylvania’s Future (PennFuture).

Response: The emission rates for the quench towers were based on the estimates made 

during the permitting of these units, and the control strategy for 2014 should not be modified 

on the basis of recent poor water quality. Pre-treating the water would not advance 

attainment by a year. ACHD will forward concerns over future water quality issues with the 

PA DEP.

25. Comment: The revised SIP does not model attainment of the 2006 24-hour NAAQS for 

fine particulate matter. Effective December 18, 2006, the 24-hour NAAQS for fine 

particulate matter was reduced from 65 μg/m3 to 35 μg/m3. The revised SIP projects that the 

24-hour of fine particulate matter at the Liberty monitor will be 42 μg/m3, significantly in 

excess of the 35 μg/m3 standard.

Commenter: John K. Baillie, Senior Attorney, and Tiffany Hickman, Western PA Outreach 

Coordinator, Citizens for Pennsylvania’s Future (PennFuture).

Response: The nonattainment areas under the 35 μg/m3 24-hour standard were made final in 

December 2009, which then require attainment plans to be developed by December 2012. 

The 35 μg/m3 implementation guidance has yet to be published, and the years to be used in 

the 35 μg/m3 plan are based around 2007 rather than 2002. Attainment of the 35 μg/m3 

standard will be demonstrated in a future, separate SIP.

26. Comment: The original plan relied in part on an agreement between the County and US 

Steel to shut down Clairton batteries 1-3 on the belief the batteries were in such poor 

condition they could not be brought into compliance. The revised SIP relies on a new 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 102

agreement with US Steel to repair the batteries and keep them operating. If these old 

batteries are to come into compliance through a course of repairs, US Steel must carry out the 

repair plan with maximum care and attention to detail, and County oversight of the repair 

work and battery performance should be just as vigilant.

Commenter: Joseph Osborne, Legal Director, The Group Against Smog and Pollution 

(GASP).

Response: ACHD agrees with this comment.

27. Comment: Additional measures to reduce fine particulate matter pollution above and 

beyond those required by the amended Consent Order and Agreement still need to be 

determined and implemented. Such measures might include the accelerated construction of 

new coke batteries at Clairton Works and the accelerated shutdown or rebuild of old coke 

batteries. ACHD and U.S. Steel must also evaluate and implement additional measures to 

limit PM2.5 emissions from U.S. Steel’s J. Edgar Thomson Works, which is just upwind from 

the Liberty-Clairton area, and adds PM2.5 pollution to the air in the Liberty-Clairton area.

Commenter: John K. Baillie, Senior Attorney, and Tiffany Hickman, Western PA Outreach 

Coordinator, Citizens for Pennsylvania’s Future (PennFuture).

Response: The control strategy as described in the SIP has been demonstrated in the SIP to 

be more than adequate to meet the standards. 

28. Comment: The original and revised SIP fail to evaluate volatile organic compound 

(VOC) contribution to PM2.5 formation. Although the Clean Air Fine Particle 

Implementation Rule presumes that control measures for VOCs need not be considered in a 

SIP for PM2.5, that presumption does not apply if the agency that develops the SIP has 

information that shows that it is not technically justified. In their comments to the original 

SIP, PennFuture and GASP presented ACHD with information that demonstrates that the 

presumption that VOCs do contribute to PM2.5 formation in the Liberty-Clairton area. 

ACHD should evaluate the contribution of VOCs to PM2.5 pollution and include appropriate 

control measures in the revised SIP.

Commenter: John K. Baillie, Senior Attorney, Citizens for Pennsylvania’s Future 

(PennFuture).

Response: The Pennsylvania Department of Environmental Protection (PA DEP) addressed 

this issue for the entire Pittsburgh-Beaver Valley region in its PM2.5 SIP. PA DEP 

considered the data in the CMU report on air toxics in Allegheny County and other available 

data that EPA suggests would be appropriate to consider in developing a demonstration to 

reverse the default presumption that VOCs do not need to be included in the PM2.5 attainment 

plan for the Pittsburgh-Beaver Valley area. PA DEP concluded that there was too much 

uncertainty regarding the role of VOCs in the formation of fine particulate to reverse the 
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 103

presumption at this time. Since the Liberty-Clairton area is small in size, and that VOCs 

require time to react in the atmosphere to create particulates, the Department has come to the 

same conclusion. 

29. Comment: The new plan will lead to improved air quality sooner and below the margin 

of error. ACHD should continue working with industry in the Monongahela Valley and 

incorporate the concerns of the people into plans.

Commenters: A. Michele Tedder, MSN, RN, Community Outreach Director, Pediatric 

Environmental Medicine Center, Children's Hospital of Pittsburgh of UPMC. Patricia Jones, 

resident of the Mon Valley. 

Response: ACHD appreciates all comments and will continue to control PM2.5 in the 

Monongahela Valley.
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 104

15.5. Certifications of Approval and Adoption
Liberty-Clairton PM2.5 SIP Revision April 2011 Page 105

The following certifications apply to the regulation changes to Allegheny County’s Article XXI 

in accordance with the previously submitted SIP revision (June 2010). These regulation changes 

were enacted by County Ordinance 11-10-OR and became effective on May 24, 2010.
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