Pennsylvania Department. of Envi~on~enta~ Protection 

Rachel Carson State Office Building 

P.O. Box 2063 

Harrisburg, PA 17105-2063 

November 10, 2009 

Secretary 

William C. Early 

Acting Regional Administrator 

U.S. Environmental Protection Agency, Region III 

1650 Arch Street (Mail Code: 3RAOO) 

Philadelphia, PA 19103-2029 

Dear Mr. Early: 

717-787-2814 

In accordance with Section 172 of the Clean Air Act, 42 U.S.C. § 7502, I am pleased to 

submit the attainment demonstration and base year inventory for the Pittsburgh-Beaver Valley 

fine particulate (PM2.5) nonattainment area (Pittsburgh-Beaver Valley Area) for approval as a 

revision to Permsylvania's State Implementation Plan (SIP). The Pittsburgh-Beaver Valley Area 

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

Armstrong, Greene and Lawrence counties. This SIP revision, which is based, in part, on 

photochemical grid modeling, air quality trends, and emission trends, demonstrates how the 

Commonwealth will attain the health-based PM2.5 National Ambient Air Quality Standard 

(NAAQS) by April 2010. The public participation process for this SIP revision included a public 

hearing in Pittsburgh on October 6, 2009, and a 30-day written comment period, which closed on 

October 9, 2009. 

I have enclosed two hard copies and one compact disk of the SIP revision for the 

Pittsburgh-Beaver Valley Area PM2.5 nonattainment area. This submittal includes the following: 

(l) attainment demonstration and base year inventory (including the mobile emissions budget for 

purposes of transportation conformity); (2) certification of public participation activities; (3) 

technical appendices (appendices consisting of data files are provided in electronic form only); 

and (4) comment and response document. In addition, the SIP submittal includes an analysis of 

reasonable further progress, the base year 2002 emissions inventory, analysis of reasonably 

available control measures, a description of contingency measures that will be implemented to 

bring the area back into attainment should violations ofthe NAAQS occur after the standard is 

attained, and mobile source emission budgets for purposes of transportation conformity. 

Thank you in advance for the expeditious review and processing of this SIP submittal. 

Please contact Joyce E. Epps, Director, Bureau of Air Quality, bye-mail atjeepps@state.pa.us or 

by telephone at 717-787-9702, if you have questions or need additional information. 

Enclosures 

An Equal Opportunity Employer 

Since~f\. ~~e.-

John Hanger 

Secretary 

www.dep.state.pa.us Printed on Recycled paper@ 
Commonwealth of Pennsylvania

STATE IMPLEMENTATION PLAN REVISION: 

ATTAINMENT DEMONSTRATION AND BASE 

YEAR INVENTORY 

PITTSBURGH-BEAVER VALLEY

FINE PARTICULATE NONATTAINMENT AREA

NOVEMBER 2009

Bureau of Air Quality

Pennsylvania Department of Environmental Protection

P.O. Box 8468

Harrisburg, PA 17105-8468

717-787-9495

www.depweb.state.pa.us

John Hanger

Secretary

Edward G. Rendell

Governor
blank for two-sided copying 
Table of Contents

Executive Summary............................................................................................................. i

I. INTRODUCTION AND OVERVIEW.......................................................................... 1

A. Health and Environmental Effects of Fine Particulate Matter (PM2.5).............. 1

B. Sources of PM2.5 and Implications for Reduction................................................. 1

C. Purpose and Structure of this Document............................................................... 4

D. Public Participation ................................................................................................. 5

II. NATURE OF THE PROBLEM IN THE PITTSBURGH-BEAVER VALLEY AREA

............................................................................................................................................. 7

A. Background.............................................................................................................. 7

B. Air Quality Monitoring Trends Analysis.............................................................. 8

1. Design Value Trend ............................................................................................... 8

2. NO2 Monitoring Trend......................................................................................... 10

3. SO2 Monitoring Trend ......................................................................................... 11

C. Seasonal Variability .............................................................................................. 11

1. FRM Monitoring Trends...................................................................................... 11

2. Speciation Monitoring Trends ............................................................................. 11

III. EMISSION INVENTORIES ..................................................................................... 13

A. Summary of 2002 Emissions ................................................................................ 14

B. Summary of Inventory Methodologies................................................................ 15

C. Projected Inventories............................................................................................ 18

1. Summary of 2009 Estimated Emissions.............................................................. 18

2. Growth Projection Methodologies....................................................................... 18

D. Reasonable Further Progress (RFP) Requirements .......................................... 21

E. Motor Vehicle Emission Budgets for Transportation Conformity................... 22

IV. CONTROL STRATEGIES ....................................................................................... 25

A. Permanent and Enforceable Control Measures................................................. 25

1. Stationary Point Sources...................................................................................... 25

2. Highway Vehicle Sources.................................................................................... 27

3. Nonroad Sources.................................................................................................. 30

B. Reasonably Available Control Measures/Reasonably Available Control 

Technology Analysis................................................................................................... 31

C. Other Measures - VOC Control Measures......................................................... 33

V. ATTAINMENT DEMONSTRATION AND WEIGHT OF EVIDENCE (WOE)..... 34

A. Attainment Demonstration Background and Objectives.................................. 34

B. Pittsburgh-Beaver Valley Area Conceptual Model Description....................... 35

C. Modeling Domain and Photochemical Modeling System.................................. 37

D. Model Performance Evaluation........................................................................... 39

1. Daily PM2.5 Mass ................................................................................................. 39

2. PM2.5 Speciation................................................................................................... 41

E. Projected 2009 Design Values for the Pittsburgh –Beaver Valley 

Nonattainment Area ................................................................................................... 43

1. Overview............................................................................................................... 43

2. Modeled Attainment Test .................................................................................... 43

3. Determine Baseline Design Values ..................................................................... 44

4. Relative Response Factor Calculations................................................................ 46

5. Annual SMAT Results......................................................................................... 47

6. 24-Hour SMAT Results....................................................................................... 49
F. Unmonitored Area Analysis............................................................................... 50

G. Local Area Analysis.............................................................................................. 51

H. Weight of Evidence and Other Documentation Supporting Attainment ........ 53

I. Conclusions............................................................................................................. 58

VI. CONTINGENCY MEASURES FOR THE ATTAINMENT DEMONSTRATION 59

A. Contingency Measure Requirement.................................................................... 59

B. Identified Contingency Measures........................................................................ 60

ACRONYMS AND ABBREVIATIONS......................................................................... 65

Table of Tables

Table E-1: Summary of Pittsburgh-Beaver Valley Area Direct PM2.5 and Precursor 

Emissions ..................................................................................................................iii

Table II-1: Pittsburgh-Beaver Valley Area Annual PM2.5 Average and Design Value 

Trend (ug/m3)............................................................................................................ 8

Table III-1: 2002 Annual Emissions (Tons per Year) ................................................ 15

Table III-2: 2009 Projected Emissions (Tons per Year)............................................. 18

Table III-3: Regional Nonattainment Area VMT and Emissions............................ 21

Table III-4 Comparison of 2009 On-Road Mobile Precursor Emissions to the Total 

Projected 2009 Inventory ....................................................................................... 23

Table III-5: Motor Vehicle Emission Budgets............................................................. 23

Table IV-1: Summary of Emission Reductions 2002-2009 from Control Measures 25

Table V-1: Annual PM2.5 Quarterly RRF Values ........................................................ 48

Table V-2: Annual SMAT Results for the Pittsburgh-Beaver Valley Area 2009 OnThe-Books-On-The-Way Control Measures ........................................................ 48

Table V-3: 24-hour PM2.5 Quarterly RRF Values....................................................... 49

Table V-4: 24-hour SMAT Results for the Pittsburgh-Beaver Valley Area 2009 OnThe-Books-On-The-Way Control Measures ........................................................ 50

Table V-5: Summary of Large PM2.5 Sources near the North Braddock Monitor... 52

Table V-6: Summary of PM2.5 Weight of Evidence Guidelines (EPA Guidance)..... 54

Table VI-1: Changes in Design Value and Emissions Expected by 2009.................. 59

Table VI-2: Calculation of Required and Excess Emissions Reductions ................. 60

Table VI-3: Calculation of Required Contingency Plan Reductions........................ 60

Table of Figures

Figure E-1: Map of Southwestern Pennsylvania PM2.5 Nonattainment Areas.......... ii

Figure 1: Pittsburgh-Beaver Valley Area Monitor Trend ........................................... 9

Figure 2: NO2 Monitoring Trend ................................................................................. 10

Figure 3: SO2 Monitoring Trend.................................................................................. 11

Figure 4: Pennsylvania’s PM2.5 Nonattainment Areas ............................................... 35

Figure 5: Pittsburgh-Beaver Valley Area Percentage of Total Mass........................ 37

Figure 6. OTC Modeling Study Domain...................................................................... 38

Figure 7: Mean Fractional Error ................................................................................. 40

Figure 8: Mean Fractional Bias.................................................................................... 41

Figure 9: Time Series of SO4 Mass............................................................................... 42

Figure 10. Wind Rose: North Braddock Monitoring Location (1998-2000) ............ 53

Figure 11: Pittsburgh-Beaver Valley Area PM2.5 Trends.......................................... 57
APPENDICES

APPENDIX A: AIR QUALITY MONITORING INFORMATION 

A-1 United States Environmental Protection Agency Air Quality System Quick Look: 

Pennsylvania (1999-2008)

A-2 United States Environmental Protection Agency Air Quality System: Quarterly PM2.5

Data (1999-2008)

APPENDIX B: STATIONARY POINT SOURCES 

B-1 Methodology – Preparation of Pennsylvania Point Source Inventories and Instructions 

for Completing the Annual Emissions Reporting Forms

B-2 Facility Annual Emissions 

B-3 Banked Emissions Reduction Credits

APPENDIX C: STATIONARY AREA SOURCES 

C-1 Pennsylvania 2002 Area Source Criteria Air Pollutant Emission Estimation Methods

(EH Pechan, Feb. 2004)

C-2 Area Source Annual Emissions 

APPENDIX D: EMISSIONS PROJECTIONS 

D-1 Development of Emission Projections for 2009, 2012, and 2018 for NonEGU Point, 

Area, and Nonroad Sources in the MANE-VU Region (MACTEC, Feb. 2007)

D-2 Documentation of 2018 Emissions from Electric Generating Units in the Eastern 

United States for MANE-VU’s Regional Haze Modeling (Alpine Geophysics, April 

2008)

D-3 Future Year Electricity Generating Sector Emission Inventory Development Using the 

Integrated Planning Model (IPM®) in Support of Fine Particulate Mass and Visibility 

Modeling in the VISTAS and Midwest RPO Regions (ICF, April 2005)

APPENDIX E: HIGHWAY VEHICLE SOURCES INVENTORY INFORMATION

E-1 Mobile Source Highway Emissions Inventory – An Explanation of Methodology

E-2 Highway Emissions Estimates

E-3 MOBILE6.2 Input Parameter Summary

E-4 MOBILE6.2 Sample Input File (available electronically)

E-5 Traffic Growth Forecasting System Report

APPENDIX F: NONROAD SOURCES 

F-1 Emissions Estimation Methodology

F-2 Nonroad Source Emissions

APPENDIX G: REASONABLY AVAILABLE CONTROL MEASURES

G-1 Identification and Evaluation of Candidate Control Measures, Final Technical 

Support Document (MACTEC, Feb. 2007)

G-2 OTC Initial List of Measures (Appendix B of Candidate Control Measures TSD)

G-3 Assessment of Reasonable Progress for Regional Haze in MANE-VU Class I Areas

(MACTEC, July 2007)

APPENDIX H: MODELING DEMONSTRATION

H-1 CMAQ Model Performance and Assessment for Base Year 2002 PM2.5 Mass and 

Speciation (NY DEC, Dec. 2007)

H-2 Meteorological Modeling of 2002 Using Penn State/NCAR 5th Generation Mesoscale 

Model (MM5) (NY DEC, Mar. 2006)

H-3 Processing of 2002 Anthropogenic Emissions: OTC Regional and Urban 12km Base 

Year Simulation (NY DEC, Mar. 2007)

H-4 PM2.5 Modeling Using the SMOKE/CMAQ System Over the Ozone Transport Region

(OTR) (NY DEC, Feb. 2006)

H-5 Processing of 2002 Biogenic Emissions for OTC / MANE-VU Regional and Urban 

Modeling (NY DEC, Sep. 2006)

H-6 Final Air-Quality Modeling Protocol for the Annual PM2.5 NAAQS: Pittsburgh-Beaver 

Valley Annual PM2.5 Nonattainment Area (PA DEP, Oct. 2007)

H-7 Sample Calculation of Projected 2009 PM2.5 Annual and 24-hour Concentrations
blank for two-sided copying 
- i -

Executive Summary

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

that include: acids (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 

micrometers (μm) in diameter, approximately 1/30th the diameter of a human hair.

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

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

lung diseases and have been linked to effects such as cardiovascular symptoms, cardiac 

arrhythmias, heart attacks, respiratory symptoms, asthma attacks, and bronchitis. These 

effects can result in increased hospital admissions, emergency room visits, absences from 

school or work, and restricted activity days. Individuals that may be particularly sensitive 

to fine particle exposure include people with heart or lung disease, older adults, and 

children.

The United States Environmental Protection Agency (EPA) issued fine particle (PM2.5) 

national ambient air quality standards (NAAQS) in 1997 after evaluating hundreds of 

health studies and conducting an extensive peer review process. The EPA established an 

annual primary (health-based) and secondary (welfare-based) standard of 15.0 

micrograms per cubic meter (μg/m3), based on the 3-year average of annual mean PM2.5

concentrations. The EPA also established a primary and secondary 24-hour standard of 

65 μg/m3determined by the 3-year average of the 98th percentile of 24-hour 

concentrations. 

On December 17, 2004, the EPA issued air quality designations for the PM2.5 standard

based on air quality monitoring data from 2001-2003. The final designations were 

published in the Federal Register on January 5, 2005 (70 FR 944). The designations 

became effective on April 5, 2005. On April 5, 2005, the EPA issued a supplemental 

notice changing the designation of certain areas from nonattainment to attainment based 

on newly available air quality data (70 FR 19844; published in the Federal Register on

April 14, 2005). The EPA designated eight areas in Pennsylvania as PM2.5 nonattainment 

areas, comprising all or parts of 21 Pennsylvania counties.

The Pittsburgh-Beaver Valley PM2.5 Nonattainment Area (Pittsburgh-Beaver Valley

Area) is located in southwestern Pennsylvania and consists of Beaver, Butler, 

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

and Lawrence counties. The Pittsburgh-Beaver Valley Area is required to attain the 

PM2.5 NAAQS no later than five years from the effective date of designation, or April 5, 

2010. 

As shown in Figure E-1, five municipalities near the Clairton Coke Works in Allegheny 

County are designated as a separate nonattainment area, the Liberty-Clairton PM2.5

Nonattainment Area. The Liberty-Clairton PM2.5 Nonattainment Area was designated as 
- ii -

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

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

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

Area. The Liberty-Clairton PM2.5 Nonattainment Area was also previously designated as 

a PM10 nonattainment area. 

Figure E-1: Map of Southwestern Pennsylvania PM2.5

Nonattainment Areas

This State Implementation Plan (SIP) revision contains information on PM2.5 trends and 

emissions and demonstrates that the Pittsburgh-Beaver Valley Area meets all 

requirements necessary for an approvable SIP revision. This SIP revision also establishes 

motor vehicle budgets for purposes of transportation conformity. Once the EPA 

approves the budgets for purposes of conformity, the Pittsburgh-Beaver Valley Area’s 

designated Metropolitan Planning Organization (MPO), the Southwestern Pennsylvania

Commission, must use these budgets in its air quality analyses for transportation planning 

purposes.

PM2.5 can be emitted directly or formed secondarily in the atmosphere by chemical 

reactions of gases in the atmosphere. Potential precursors of secondary PM2.5 include 

sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOC), and 

ammonia (NH3).

 
- iii -

While emissions of direct PM2.5 are projected to increase from 2002 to 2009 in the 

Pittsburgh-Beaver Valley Area, emissions of the PM2.5 precursors SO2 and NOx are 

projected to decrease over the same time period. The emissions inventory shows this 

apparent increase in PM2.5 emissions from stationary sources from 2002 to 2009 because 

the 2002 inventory was based on emissions reported to the Pennsylvania Department of 

Environmental Protection (DEP or Department) by facilities and did not include 

condensable PM for many facilities. The projected 2009 PM2.5 emissions for electric 

generating units (EGUs) include condensable PM emissions which were calculated based 

on factors derived from defaults contained in AP 42 Fifth Edition, Compilation of Air 

Pollutant Emission Factors.

. The emission projections take into account both growth in economic activity that 

increases emissions and control measures implemented to reduce emissions. Based on 

speciated data from the Lawrenceville monitor, sulfates and nitrates account for 46% of 

the PM2.5 mass in the Pittsburgh-Beaver Valley Area. Because sulfates and nitrates are

formed from atmospheric reactions of SO2 and NOx, the reduction of emissions of SO2

and NOx is expected to result in attainment of the PM2.5 air quality standard in the 

Pittsburgh-Beaver Valley Area.

Table E-1: Summary of Pittsburgh-Beaver Valley Area Direct PM2.5 and Precursor 

Emissions

Pollutant 2002 2009

PM2.5 14904 27969

PM10 54879 69613

SO2 476871 129074

NOx 198483 111897

VOC 80898 63230

NH3 5303 6440

The permanent and enforceable control measures that enable the Pittsburgh-Beaver 

Valley Area to demonstrate attainment of the PM2.5 NAAQS include:

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

pollution transport;

State regulation of smaller sources of nitrogen oxides, cement kilns and large 

stationary internal combustion engines;

The Pennsylvania and federal new motor vehicle emission control programs for 

passenger and light-duty trucks; 

The Pennsylvania and federal heavy-duty diesel emission control programs;

Federal fuel programs for highway vehicles and nonroad mobile equipment; and

Federal regulation of offroad diesel and gasoline-powered vehicles and 

equipment.
- iv -

In addition, Pennsylvania’s Diesel-Powered Motor Vehicle Idling Act of 2008 will assist 

the Pittsburgh-Beaver Valley Area in attaining and maintaining air quality.

Pennsylvania and other member states of the Ozone Transport Commission (OTC) and 

Mid-Atlantic/Northeast Visibility Union (MANE-VU) worked together to analyze 

potential control measures. The Pennsylvania Department of Environmental Protection 

(Department), based on this process that included stakeholders and the other

OTC/MANE-VU states, concluded that there are no additional reasonable cost-effective 

measures that would advance the ability of the area to attain the standard by one year or 

more. 

The OTC’s modeling platform, the Community Multi-scale Air Quality (CMAQ) 

photochemical grid model (version 4.5), was used to estimate projected 2009 PM2.5

concentrations within the Pittsburgh-Beaver Valley Area. CMAQ is an Eulerian grid 

model capable of simulating air pollutant concentrations in the atmosphere using 

mathematical equations to characterize chemical and physical properties.

A review of the base case (2002) run indicated the CMAQ model did a reasonable job 

reproducing actual concentrations. Based on this analysis, it is reasonable to assume the 

model can estimate the projected PM2.5 concentrations within the Pittsburgh-Beaver 

Valley Area for 2009. The year 2009 will be the last complete year of annual emissions 

and ambient monitoring data that the EPA will use to determine whether the PittsburghBeaver Valley Area achieves attainment in April 2010.

Projected PM2.5 concentrations from CMAQ indicate the Pittsburgh-Beaver Valley Area

will attain the annual and 24-hour PM2.5 standards in 2009. Additional evidence 

supporting this conclusion includes recent lower concentrations at monitors within the 

Pittsburgh-Beaver Valley Area, significant SO2 controls installed on large sources within

and near the Pittsburgh-Beaver Valley Area and possible model under-predictions of the 

air quality benefits of emission reductions.

A number of potential emission control measures were developed during the OTC/

MANE-VU/Mid-Atlantic Regional Air Management Association (MARAMA)

collaborative strategy development process. These measures are outlined in the technical 

support document titled: Development of Emission Projections for 2009, 2012, and 2018 

for NonEGU Point, Area, and Nonroad Sources in the MANE-VU Region, developed by 

MARAMA. This document, which can be found in Appendix D-1, provides details on 

the specific factors, control assumptions, and implementation schedules used in the 

emission projection calculations for each source category.

This SIP revision contains a contingency plan that provides assurance that should the 

Pittsburgh-Beaver Valley Area fail to meet a milestone, fail to attain the NAAQS by the 

attainment date or violate the standard during the maintenance period, the area can be 

brought back into attainment as expeditiously as practicable. 
1

I. INTRODUCTION AND OVERVIEW

A. Health and Environmental Effects of Fine Particulate Matter (PM2.5)

Particulate matter (PM) includes both solid and liquid particles suspended in the air. PM is 

chemically and physically diverse and originates from a variety of human and natural 

activities. PM is composed of particles in a wide range of sizes. Particles less than 10 

micrometers in diameter (PM10) pose a health concern because they can be inhaled into and 

accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter 

(PM2.5) are referred to as fine particles and generally pose the largest health risks. Because 

of their small size, fine particles can penetrate deeply into the lungs.

Many scientific studies have linked exposure to elevated levels of PM2.5 to premature 

death, aggravated respiratory disease, including asthma and chronic bronchitis, 

cardiovascular disease, changes in lung function and increased respiratory problems, such 

as coughing and painful breathing, as well as increased susceptibility to respiratory 

infections. Individuals particularly sensitive to PM2.5 exposure include older adults, people 

with heart and lung disease and children.

The recent article, “Fine-Particulate Air Pollution and Life Expectancy in the United 

States” by C. Arden Pope, III, et al., was published in the New England Journal of 

Medicine on January 22, 2009. The authors of the article were able to demonstrate that 

decreased PM2.5 concentrations contributed to a significant improvement in life 

expectancy. The study used statistical analyses to evaluate the role the PM2.5 reductions 

that occurred in the 1980s and 1990s had on the increased life expectancy observed over 

that period. The study found that a reduction of 10 micrograms per cubic meter (μg/m3) of 

PM2.5 was associated with an average increase in life expectancy of 7.3 months. 

PM2.5 has significant environmental impacts, including acid rain and stream 

eutrophication. PM2.5 also affects visibility (regional haze) through the scattering and 

absorption of light. Fine particles, similar in size to the wavelength of light, are most 

efficient, per unit of mass, at reducing visibility. Soiling and materials damage can also be 

caused by PM2.5 in the air. 

B. Sources of PM2.5 and Implications for Reduction

Fine particle pollution can be emitted directly or formed secondarily in the atmosphere. 

PM2.5 emitted directly into the air in a stable solid or liquid chemical form (including PM2.5

that is formed near its source by condensation) is referred to as “primary” PM2.5. PM2.5 

formed by chemical reactions of gases in the atmosphere is considered to be “secondary” 

PM2.5. The chemical composition of PM2.5 in an area depends on the mix of emissions, 

location, time of year, and weather. The chemical composition of PM2.5 can include 

sulfate, nitrate, ammonium, particle-bound water, black (elemental) carbon, a great variety 

of organic compounds, and miscellaneous inorganic material, such as dust and metals.
2

Primary PM2.5 includes soot from diesel engines, condensed organic material from 

incomplete combustion and compounds from condensation during combustion or smelting. 

The atmospheric chemistry of PM2.5 formation is complex. Formation of secondary PM2.5

depends on numerous factors, including the relative concentration of precursors, 

atmospheric conditions and the interactions of precursors with each other and with other 

particles, clouds or fog. The contribution of different precursors will vary by location. 

The principal forms of secondary PM2.5 include:

Sulfates, formed from emissions of sulfur dioxide from power plants and 

industrial facilities;

Nitrates, formed from emissions of nitrogen oxides from power plants, 

vehicles, and other combustion sources;

Ammonium, formed primarily from emissions of ammonia from animal 

operations; and

Secondary organic aerosol, formed from emissions of volatile organic 

compounds (VOCs) from incomplete combustion and evaporation from a 

wide diversity of sources. 

To protect public health and the environment, the United States Environmental Protection 

Agency (EPA) is required by the Clean Air Act (CAA) to set and periodically revise 

National Ambient Air Quality Standards (NAAQS) for six criteria pollutants. Particulate 

matter is one of the criteria pollutants. The EPA sets NAAQS based on its review of 

existing scientific knowledge about the adverse health and welfare effects of the pollutant. 

After the EPA sets or revises a NAAQS, states have the responsibility for devising 

strategies to attain and maintain the standard. Previous particulate matter standards were 

set for PM and PM10. In 1997, after evaluating hundreds of health studies and conducting 

an extensive peer review process, the EPA promulgated NAAQS based on the level of 

particles smaller than 2.5 micrometers (PM2.5). In setting the 1997 standards for PM2.5, the 

EPA recognized that the smaller particles were most directly associated with adverse 

health effects. 

The EPA set the annual health-based standard for PM2.5 at 15.0 μg/m3. This is determined 

by the 3-year average of annual mean PM2.5 concentrations. The EPA set the 24-hour 

standard at a level of 65 (μg/m3), as determined by the 3-year average of the 98th 

percentile of 24-hour concentrations. The EPA set levels to protect the environment at the 

same level as it set the health-based standards. While the EPA revised the 24-hour standard

in 2006 to be more protective, designation of specific nonattainment areas for the 2006 

revision to the standards were not yet effective at the time this plan was developed. 

Therefore, this document addresses attainment of the 1997 PM2.5 NAAQS. Measures 

included in this document will continue to be in place to assist with attaining the more 

protective standard in the future.

The Pittsburgh-Beaver Valley PM2.5 Nonattainment Area (Pittsburgh-Beaver Valley Area), 

located in southwestern Pennsylvania, consists of Beaver, Butler, Washington, and 
3

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

counties. Five municipalities near the Clairton Coke Works in Allegheny County are 

designated as a separate nonattainment area, the Liberty-Clairton PM2.5 Nonattainment 

Area. 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 coke plant in a narrow river valley creates a local air quality problem 

uniquely different from the remainder of the Pittsburgh-Beaver Valley Area. The LibertyClairton PM2.5 Nonattainment Area was also previously designated as a PM10

nonattainment area. 

The Pittsburgh-Beaver Valley Area was designated as nonattainment because it violated 

the 1997 annual standard of 15.0 μg/m3based on 2001-03 monitoring data. The 

Pittsburgh-Beaver Valley Area did not violate the 1997 24-hour standard of 65 μg/m3.

Because of the complexity and variability of the process of particulate matter formation,

the EPA recognizes that effective control measures for PM2.5 will vary among

nonattainment areas. In the EPA’s Clean Air Fine Particle Implementation Rule (72 FR 

20586, April 25, 2007) (the implementation rule), the EPA established general 

presumptive policies for assessing which PM2.5 precursors should be evaluated for possible 

controls. The EPA requires states to evaluate control measures for sulfur dioxide (SO2)

and primary PM2.5 in all locations. The EPA requires states to evaluate control measures 

for nitrogen oxides (NOx) unless a technical demonstration is made to show NOx does not 

significantly contribute to PM2.5. The EPA requires states to evaluate measures for VOC 

and ammonia (NH3) only if a technical demonstration is made to show they significantly

contribute to PM2.5 in that area. While this State Implementation Plan (SIP) revision 

provides emissions information for all pollutants (PM10, PM2.5, SO2, NOx, VOC and NH3),

as required, it does not provide technical demonstrations pertaining to the level of 

contribution by NOx, VOC, or NH3 to PM2.5 concentrations. Therefore, the 

Commonwealth will consider SO2 and NOx as PM2.5 precursors for purposes of this

attainment plan and reasonable further progress.1 The EPA has indicated that virtually all 

nonattainment problems appear to result from a combination of local emissions and 

transported emissions from upwind areas.2

The CAA requires that an area’s attainment date be the date by which attainment can be 

achieved as expeditiously as practicable, but no later than five years from the effective date 

of designation, or no later than April 5, 2010. If appropriate, the EPA could extend the 

attainment date up to but no later than 10 years after the date of designation. States are 

required to propose and justify an attainment date in their attainment plan. This SIP

revision sets an April 2010 attainment date for the Pittsburgh-Beaver Valley Area. The 

analysis is based on modeling of projected emissions for 2009 because 2009 will be the 

last complete year of annual emissions and ambient monitoring data that the EPA will use 

to determine if the Pittsburgh-Beaver Valley Area attains the standard by April 2010.

 

1 The EPA’s definition of PM2.5 attainment plan precursor can be found in 40 CFR Part 51, Subpart Z, 

section 51.1000.

2 Clean Air Fine Particle Implementation Rule, 72 FR 20587.
4

The EPA Administrator is authorized under Section 179(a) of the CAA to impose 

sanctions after making a finding or determination relating to a SIP revision, or after 

disapproving a SIP revision, in whole or in part. Mandatory sanctions would be imposed 

for (1) a state’s failure to submit a plan or plan element, or to make a submission that 

satisfies the minimum criteria of section 110(k) of the CAA in relation to any element of 

the plan; (2) the EPA’s disapproval of a plan in whole or in part; (3) the EPA’s 

determination that a state has failed to make a required submission, including a required 

submission satisfying the minimum criteria of section 110(k); or (4) a state’s failure to 

implement any requirement of an approved plan. If the state fails to correct any SIP 

deficiency within 18 months from the Administrator's finding, determination or 

disapproval, mandatory sanctions would be imposed. There are two mandatory sanctions 

for noncomplying states: (1) limitations on certain federal highway funding; and (2) 

"offset" limitations on certain developments in affected areas that require each new 

stationary emission source to be paired with a reduction in area emissions amounting to 

double the amount of increased emissions from the new source. 

In addition, failure to submit a plan, failure to implement a plan, or the EPA 

disapproval of a plan can also affect the ability of transportation planning agencies 

to meet transportation conformity requirements, and thus the ability to implement 

transportation projects. The EPA may also impose discretionary sanctions under 

Section 110 of the CAA. 

C. Purpose and Structure of this Document 

In December 2004, after consultation with states and receipt of public input, the EPA 

designated eight areas in Pennsylvania comprised of all or parts of 21 Pennsylvania 

counties as PM2.5 nonattainment areas based on air quality monitoring data from 2001-

2003. Under Section 110 of the CAA, the Commonwealth of Pennsylvania

(Commonwealth or Pennsylvania) is required to develop a revision to the SIP to 

demonstrate how the Pittsburgh-Beaver Valley Area will attain the standard by April 2010, 

meet emission reduction requirements in the CAA and ensure that in the event of a future 

violation or failure to meet emission reduction milestones, the area is brought back to 

attainment as quickly as possible. 

This SIP revision is organized as follows:

Section I provides general information about PM2.5 pollution, including information about 

the health and environmental impacts of PM2.5 and sources of PM2.5 and its precursors. 

Section I also provides an overview of the health-based PM2.5 standard and Pennsylvania’s 

responsibility to develop strategies to attain air quality standards.

Section II provides information characterizing the PM2.5 problem in the Pittsburgh-Beaver 

Valley Area, examines current monitoring information, and analyzes trends.
5

Section III describes emission inventories for PM2.5 and its precursors, SO2 and NOx. 

Base year and projected emission inventories are also included as required for PM10, VOC 

and NH3. Section III describes how this SIP revision meets the requirement for 

“reasonable further progress” under Section 172 of the CAA3. Section III also contains the 

highway vehicle emission budgets for purposes of transportation conformity. Technical 

information on methodologies and inputs for point, area, highway and nonroad actual and 

projected emission inventories is contained in the Appendices B through F, relating to: (1) 

stationary point sources; (2) stationary area sources; (3) emissions projections; (4) highway 

vehicle sources inventory information; and (5) nonroad sources. 

Section IV describes the control measures implemented in the Pittsburgh-Beaver Valley 

Area that produce emission reductions between 2002 and 2009 in order to attain the 

NAAQS in a timely fashion and how Pennsylvania meets the requirement for identifying 

Reasonably Available Control Measures (RACM) that could advance the attainment of the 

standard by one year or more. Appendix G, relating to Reasonably Available Control 

Measures, includes specific information and recommendations developed by the Ozone 

Transport Commission (OTC) and the Mid-Atlantic/Northeast Visibility Union (MANEVU)states for additional controls to aid in reaching attainment.

Section V discusses the modeling that was done to evaluate attainment by April 2010 and 

the “weight of evidence” analysis. Together, these comprise the attainment demonstration. 

Based on modeling, statistical analyses and other evidence, the attainment demonstration 

indicates the Pittsburgh-Beaver Valley Area will attain the 1997 PM2.5 standards by April 

2010. Appendix H includes detailed technical information on the Community Multi-scale 

Air Quality (CMAQ) model performance, meteorological data, modeling emission 

inventories and modeling analysis used to project 2009 annual and 24-hour PM2.5 design 

values.

Section VI is the contingency plan, meeting the requirement that the Commonwealth be 

able to address unanticipated failures to meet emission or air quality requirements in a 

timely fashion. 

D. Public Participation 

Requirements for a public comment process are set forth in Section 110(a)(2) of the CAA,

40 CFR Section 51.102(d) and 35 P.S. Section 4007.5 On September 5, 2009, the 

Pennsylvania Department of Environmental Protection (DEP or Department) published a 

notice of public hearing and commenced a 30-day written comment period on the proposed 

attainment demonstration and base year inventory for the Pittsburgh-Beaver Valley Area.

39 Pa.B. 5278. The Department held a public hearing in Pittsburgh on the proposed SIP 

revision on October 6, 2009. The public comment period closed on October 9, 2009. The 

Department has prepared a Comment and Response Document addressing comments 

received during the public participation process. Proof of public notice and a copy of the 

Comment and Response Document are included in the SIP submittal. 

 

3 Clean Air Fine Particle Implementation Rule, 72 FR 20633.
6
7

II. NATURE OF THE PROBLEM IN THE PITTSBURGH-BEAVER VALLEY 

AREA

A. Background

The Pittsburgh-Beaver Valley Area, located in southwestern Pennsylvania, consists of

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

Armstrong, Greene and Lawrence counties. Five municipalities near the Clairton Coke 

Works in Allegheny County are designated as a separate, local-source impacted 

nonattainment area, the Liberty-Clairton PM2.5 Nonattainment Area. Other PM2.5

nonattainment areas near the Pittsburgh-Beaver Valley Area include Morgantown, WV to 

the south, Stuebenville-Weirton, OH-WV to the west, Youngstown, OH to the northwest 

and Johnstown, PA to the east. Topographically, the Pittsburgh-Beaver Valley Area is 

bounded on the east by the high terrain of the Laurel and Chestnut Ridge Mountains. 

There are several major rivers that run through the region, including the Ohio, Allegheny, 

Monongahela, and Youghiogheny. These rivers, along with the rising terrain around them, 

create unique wind patterns.

Several types of PM2.5 monitors operate within the Pittsburgh-Beaver Valley Area. These 

include eleven federal reference method (FRM) monitors. Five of these sites are operated 

by the Department, including Beaver Falls, Charleroi, Florence, Greensburg, and 

Washington. The additional six monitors, which include Coraopolis, Harrison, 

Lawrenceville, North Braddock, North Park, and South Fayette, are operated by the 

Allegheny County Health Department (ACHD). In addition to the FRMs, three speciation 

monitors (at Florence, Greensburg, and Lawrenceville) and four continuous monitors (at 

Beaver Falls, Charleroi, Kittanning, and Lawrenceville) are maintained within the region. 

FRM data has been collected since 1999 on a one in three day frequency (1/3). Speciated 

monitoring on a one in six day frequency (1/6) has occurred since April of 2002, while the 

Tempered Element Oscillating Microbalance (TEOM) monitor has operated almost 

continuously since August 2004.
8

B. Air Quality Monitoring Trends Analysis

A short summary of monitoring trends in the Pittsburgh-Beaver Valley Area is provided as 

follows:

1. Design Value Trend

Table II-1: Pittsburgh-Beaver Valley Area Annual PM2.5 Average and Design Value 

Trend (ug/m3)

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Beaver Falls 16.14 17.19 15.26 15.67 15.38 18.30 14.87 15.72 13.69

Charleroi 15.44 15.27 15.90 15.88 14.89 13.99 16.36 14.42 15.51 13.03

Florence 12.98 13.20 14.43 13.21 13.40 13.21 14.23 11.94 13.79 11.30

Greensburg 14.90 15.78 16.11 14.96 15.32 14.92 16.81 14.32 15.26 12.67

Washington 14.58 15.16 15.85 14.49 14.74 14.14 15.88 13.08 14.83 12.27

Coraopolis * 15.63 13.38 15.33 13.63 15.71 13.26 14.67 12.38 13.64

Harrison 17.45 16.09 16.11 16.09 15.50 15.02 15.95 14.03 15.06 13.39

Lawrenceville 16.23 15.63 16.58 15.33 15.20 15.46 15.82 14.40 14.89 12.87

N. Braddock 17.69 16.45 17.09 16.92 16.80 15.79 17.16 15.03 16.38 14.15

N. Park * 11.99 14.49 14.87 13.63 13.96 12.28 14.44 11.50 13.02

S. Fayette 14.98 14.09 14.04 12.31 13.23 13.00 14.22 11.14 13.47 10.77

Max Annual 

Value

17.19 16.92 16.80 15.79 18.30 15.03 16.38 14.15

Source: Data extracted from Appendix A-1 (US EPA Air Quality System AMP 450 

Report)

* The Coraopolis and N. Park monitor were shut down for 2008 due to limited staff at 

ACHD
9

Figure 1: Pittsburgh-Beaver Valley Area Monitor Trend
10

2. NO2 Monitoring Trend

Figure 2: NO2 Monitoring Trend

Figure 2 displays the rural vs. urban annual NO2 concentration trend from 1999 to 2008. 

The rural monitor is adequately represented by the monitored values at Florence. The 

urban monitor is adequately represented by the Pittsburgh (Carnegie) monitor.
11

3. SO2 Monitoring Trend

Figure 3: SO2 Monitoring Trend

The following graph displays the rural vs. urban annual SO2 concentration trend from 1999 

to 2008. The rural monitor is adequately represented by the monitored values at Florence. 

The urban monitor is adequately represented by the Pittsburgh (Carnegie) monitor.

C. Seasonal Variability

1. FRM Monitoring Trends

Summary of seasonal variability in FRM data: There appears to be little variability in 

quarterly FRM values at monitors located in the Pittsburgh-Beaver Valley Area. In the 

more urbanized areas, monitored values during the 1st, 2nd and 3rd quarters tend to run 

higher than 4th quarter values. By contrast, the monitoring sites in rural areas (such as 

Florence and South Fayette) have substantially higher 2nd and 3rd quarter averages than 1st

and 4th quarter averages.

2. Speciation Monitoring Trends

Summary of seasonal variability in speciated data: Raw speciation data for the 

Pittsburgh-Beaver Valley Area indicates some seasonal variability in the primary 

components. Sulfates have the largest variability with 1st quarter concentrations 

approximately half concentrations measured in the 3

rd quarter. Nitrates vary in nearly the 
12

opposite direction with 1st quarter measurements higher than 2nd, 3

rd and 4th quarter 

measurements. Organic carbon, elemental carbon, ammonium and crustal mass do not 

appear to show much seasonal variability. 
13

III. EMISSION INVENTORIES 

Section 51.1008 of 40 CFR Part 51 requires an inventory of pollutants to meet the 

requirements of section 172(c)(3) of the CAA. As specified by the EPA, the pollutants 

inventoried by Pennsylvania include PM10, PM2.5, SO2, NOx, VOC, and NH3. In addition, 

projections of future emissions have been made for the milestone year 2009. Information 

on the manmade sources of direct PM and its potential precursors, SO2, NOx, VOC, and 

NH3 was compiled for:

“Stationary sources” (or “point” sources), which are sources for which the 

Department collects individual emissions-related information. Generally, they 

represent major stationary sources but may be smaller.

“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. Where there is overlap between stationary point sources and 

stationary area sources, the area source values are adjusted to remove any double 

counting.

“Highway vehicles,” which include passenger cars and light-duty trucks, other 

trucks, buses and motorcycles. 

“Nonroad sources,” which 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 inventory for the Pittsburgh-Beaver Valley Area was compiled for the following 

counties and partial counties that comprise the nonattainment area: 

Beaver, Butler, Washington, and Westmoreland counties 

Armstrong County (partial) – Elderton Borough, Plumcreek Township, and 

Washington Township

Greene County (partial) – Monongahela Township

Lawrence county (partial) – Township of Taylor south of New Castle City

Allegheny County (partial) – entire county except Lincoln Borough, 

Clairton City, Glassport Borough, Liberty Borough, and Port Vue Borough

which comprise the Liberty-Clairton PM2.5 Nonattainment Area.

Emissions were estimated for the partial counties in the nonattainment area as follows. 

Point source emissions were included in the inventory if the point source is located in the 

nonattainment area. Area source and nonroad source emission estimates were apportioned 
14

to the nonattainment area based on the percentage of county population in the 

nonattainment municipalities, using U.S. Census Bureau sub-county population data. 

Mobile source VMT and emissions were estimated for the partial counties in the 

nonattainment area using the following methodology. The townships within each partial 

county were identified based on the nonattainment area designation description. Using 

GIS, township boundaries were overlaid on the PennDOT Roadway Management System 

(RMS) state roadway segments and used to identify which road segments fell within the 

nonattainment area. These state roadway segments were used for the analysis of VMT and 

emissions for non-local state-owned roadways.

The PennDOT RMS roadway data contains some local segments (those which are stateowned and function as local roads). Since the RMS database does not contain a 

comprehensive representation of local roads, local VMT is typically reconciled to the 

reported HPMS local VMT for each county in Pennsylvania. For the partial areas the 

following methods were used to estimate local VMT:

Three methods were analyzed for each partial county in the nonattainment area and the 

highest values were chosen to ensure that local VMT was not under-represented in the 

analysis. These values were used to estimate emissions for the partial counties in the 

nonattainment area. The methods are:

 Calculate local VMT based on local road segments in RMS database (as discussed this 

could underestimate local VMT)

 Using GIS, determine the portion of the Topologically Integrated Geographic 

Encoding and Referencing (TIGER)4roadway local mileage in the nonattainment 

municipalities vs. county total and apply this percentage to county HPMS local VMT.

 Determine the percentage of population in nonattainment municipalities versus the 

county population and apply this percentage to county HPMS local VMT.

A. Summary of 2002 Emissions

An emission inventory is an estimate of the emissions from sources in a particular area. 

The Department developed an emission inventory for 2002, which is the base year for 

attainment planning purposes with respect to 8-hour ozone and PM2.5 SIPs, and for 

planning purposes with respect to the regional haze SIPs. The 2002 base year inventory 

includes the pollutants PM10, PM2.5, SO2, NOx, VOC, and NH3. The inventory consists of

sources in four sectors: stationary point sources, stationary area sources, highway vehicle 

sources and nonroad sources. MANE-VU compiled a regional inventory from the 

 

4 The Census Bureau's Geography Division maintains two databases used in this analysis. The MAF, or 

Master Address File, is a complete and current list of all addresses and locations where people live or 

work, covering an estimated 115 million residences, as well as 60 million businesses and other structures 

in the U.S. The TIGER®is a digital database that identifies the type, location and name of streets, rivers, 

railroads and other geographic features, and geospatially defines their relationships to each other, to the 

MAF addresses, and to numerous other entities. See http://www.census.gov/geo/www/tiger 
15

emission inventories of the Northeastern and Mid-Atlantic states. This regional inventory 

was used to perform the regional modeling analysis used in Pennsylvania’s air quality 

management planning efforts to attain the 8-hour ozone NAAQS and the PM2.5 NAAQS,

and to prepare the regional haze plan. 

An emissions inventory for the base year, 2002, was developed in accordance with EPA 

guidance5. Table III-1 summarizes the emissions for 2002. 

Table III-1: 2002 Annual Emissions (Tons per Year)

Pittsburgh-Beaver Valley 

Area 2002 PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 4868 11149 463501 110618 5157 462

Area Sources 7916 41206 9905 8622 36683 2948

Highway Vehicle Sources 824 1164 1770 53268 25638 1884

Non-Road Sources 1297 1359 1694 25975 13421 8

Totals 14904 54879 476871 198483 80898 5303

B. Summary of Inventory Methodologies

Inventory development methodology is summarized below. 

Stationary Point Sources. The Department requires owners and operators of larger 

facilities to submit annual production figures and emission calculations each year. 

Throughput data are multiplied by emission factors from Factor Information Retrieval 

(FIRE) Data System and the EPA’s publication series AP-42 and are based on Source 

Classification Code (SCC). Each process has at least one SCC assigned to it. If the owners 

and operators of facilities provide more accurate emission data based upon other factors, 

these emission estimates supersede those calculated using SCC codes. Appendix B-1

includes information on stationary point source emission methodology, and Appendix B-2 

is the data set for facility 2002 annual emissions. Appendix B-3 is a table documenting the 

banked emissions reduction credits for the Pittsburgh-Beaver Valley Area in the 2009 

emission projection.

The 2002 inventory was based on emissions reported to the Department by facilities. In 

2002, many facilities did not include condensable PM in their estimates of direct PM

emissions. Condensable PM is a vapor or gas at stack temperature that condenses to a 

liquid or solid at stack exit. 

Area Sources. Area source emissions are generally estimated by multiplying an emission 

factor by some known indicator or collective activity for each area source category at the 

 

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

Quality Standards (NAAQS) and Regional Haze Regulations – EPA-454/R-05-001. August, 2005. Updated 

November, 2005.
16

county level. Pennsylvania estimates emissions from area sources using emission factors 

and SCC codes in a method similar to that used for Stationary Point Sources. Emission 

factors may also be derived from research and guidance documents if those documents are 

more accurate than FIRE and AP-42 factors. Throughput estimates are derived from 

county-level activity data, by apportioning national or statewide activity data to counties, 

from census numbers, and from county employee numbers. County employee numbers are 

based upon North American Industry Classification System (NAICS) codes to establish 

that those numbers are specific to the industry covered. More specific information on the 

procedure used for each industry type is contained in Pennsylvania 2002 Area Source 

Criteria Air Pollutant Emission Estimation Methods, (E.H. Pechan & Associates, Inc., 

February 2004) which is contained in Appendix C-1. Appendix C-2 is a table containing

stationary area sources emissions data for the Pittsburgh-Beaver Valley Area.

Highway Vehicle Sources. The Department employs an emissions estimation 

methodology that uses the current EPA-approved highway vehicle emission model, 

MOBILE 6.2, to estimate highway vehicle emissions. In addition, Pennsylvania uses a 

MOBILE pre- and post-processing software package called PPSUITE to process and 

compile Pennsylvania’s robust highway network and detailed highway vehicle data. The 

Pennsylvania Department of Transportation (PennDOT) provided estimates of vehicle 

miles traveled (VMT) by vehicle type and roadway type. The Pennsylvania methodology 

is consistent with the January 2002 guidance published by the EPA’s Office of 

Transportation and Air Quality (OTAQ) entitled, Technical Guidance on the Use of 

MOBILE6 for Emissions Inventory Preparation. 

More information on highway emission methodology is available in Appendix E. 

Appendix E-1 provides the 2002 base year and 2009 projections of mobile (highway) 

VMT and annual PM2.5 direct and precursor emissions. The document summarizes the 

methodology and data inputs used to produce the mobile emissions inventory. Appendix 

E-2 is the table of 2009 Pittsburgh-Beaver Valley Area Annual Highway Emissions listed 

by SCC. Appendix E-3 describes the inputs to MOBILE6.2 used to generate emission 

factors for a specific area. Some examples of the inputs described in Appendix E-3 are the 

type and frequency of vehicle emission testing, the fuel types required in the area, 

temperatures by month, and fleet age. The summary in Appendix E-3 indicates when 

default information contained in the model is used rather than specific area information. 

Finally, Appendix E-4 is an electronic file that provides all of the input coding for a sample 

segment and scenario used in Pennsylvania’s MOBILE6.2 modeling system.

Nonroad Sources. The 2002 emissions for the majority of nonroad emission source 

categories and pollutants were estimated using the EPA NONROAD 2005 model. The 

NONROAD model estimates emissions for diesel, gasoline, liquefied petroleum gasoline, 

and compressed natural gas-fueled nonroad equipment types and includes growth factors. 

The National Mobile Inventory Model (NMIM) was used to estimate emissions of 

ammonia from sources contained in the NONROAD model. The NONROAD model does 

not estimate emissions from aircraft, locomotives or commercial marine vessels. 

Emissions from aircraft, locomotives, and commercial marine vessels were estimated using 

EPA guidance and best available information. If specific local operational data was 
17

available, that data was used to estimate emissions. State and national data was used if 

local data was unavailable.

 

Emissions from commercial aircraft operations for 2002 were estimated using the EPAapproved Emissions and Dispersion Modeling System (EDMS) 4.20, the latest version 

available at the time the inventory was developed. Pittsburgh International Airport (PIT) 

supports the vast majority of the commercial aircraft operations in the Pittsburgh-Beaver 

Valley Area. In addition, a military wing flies cargo aircraft out of PIT. The Department 

estimated emissions using operations data obtained from the United States Department of 

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

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

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

Emissions produced by aircraft at small airports in the Pittsburgh-Beaver Valley Area were 

estimated by using airport operation statistics, which can be found at www.airnav.com and 

the Federal FAA’s Terminal Area Forecast Detailed Report. An emissions factor for a 

typical general aviation single engine, multi-engine, and jet engine aircraft were derived by 

averaging the emissions factors from a basket of emission factors for common aircraft of 

each of the three types of aircraft. Emission factors and operational characteristics 

contained in EDMS were used. The proportion of operations among the three groups of 

aircraft was determined by examining the number of each aircraft type based at each 

airport. For military operations at small airports, the type of aircraft and its emission 

factors are sometimes identifiable. If not, emission factors calculated to represent an 

“average” military aircraft are used. Growth was estimated using estimates of future 

operations at Pittsburgh airports found in the FAA Terminal Area Forecast Detailed 

Report. 

For 2002 locomotive emissions, the Department projected emissions from a 1999 survey 

when the Department obtained fuel use statistics from class II and III railroads. For class I 

railroads, which produce most of the emissions in the Commonwealth, the Department 

conducted a 2002 inventory because the 1999 fuel use data for class I railroads was skewed 

by gridlock caused by the acquisition of Conrail by CSX and Norfolk Southern. Emissions 

were generated using EPA emission factors. Emissions were grown using national railroad 

fuel use trends supplied by the Association of American Railroads. 

All air emissions from commercial marine vessel (CMV) traffic in the seven county area of 

the Port of Pittsburgh were estimated using the methodology outlined in the EPA’s 

publication Commercial Marine Activity for Great Lakes and Inland River Ports in the 

United States, Final Report. A comprehensive understanding of the methodology can be 

achieved by reviewing this document. Additional information was obtained from 

conversations with tug operators in the port. Emission estimates were based on number of 

CMV trips, trip durations, lock data, and the engine size of the tug fleet based in the 

Pittsburgh-Beaver Valley Area. Emissions were distributed to the county level based on 

the number of piers, wharves, and docks in each individual county. Relevant CMV 

operational data was obtained from the U.S. Army Corps of Engineers website.
18

Appendix F-1 is the technical document providing the methodology and description of the 

procedures used to generate 2002 and 2009 county-level pollutant emission estimates for 

nonroad mobile engines included in the EPA’s NONROAD2005 model, locomotive 

engines, and aircraft operations. The table of the specific emissions data used to calculate 

the nonroad emissions sorted by source category is available as Appendix F-2.

C. Projected Inventories

1. Summary of 2009 Estimated Emissions

Table III-2 summarizes the emissions expected in 2009. These emissions take activity and 

emissions growth and/or controls from 2002 into account. Appendix D, relating to 

emissions projections, contains the technical support documents that describe the 

methodologies used to project the 2002 baseline emissions to 2009.

Table III-2: 2009 Projected Emissions (Tons per Year)

Pittsburgh-Beaver Valley 

Area 2009 PM2.5 PM10 SO2 NOx VOC NH3

Stationary Point Sources 18160 24710 114889 51361 4666 782

Area Sources 8127 42749 10452 9101 34042 3528

Highway Vehicle Sources 509 852 230 28739 14098 2121

Non-Road Sources 1142 1200 1385 21246 10055 9

Emission Reduction Credits 

Banked 31 102 2118 1450 368 0

Totals 27969 69613 129074 111897 63230 6440

Sulfur and nitrogen are the major contributors to the Pittsburgh-Beaver Valley Area’s 

PM2.5 nonattainment problem. Therefore, even though the direct PM2.5 emissions are 

predicted to increase in 2009, the reductions of PM2.5 precursors, SO2 and NOx, will ensure 

that the Pittsburgh-Beaver Valley Area attains the PM2.5 NAAQS by 2010. The emissions 

inventory shows this apparent increase in PM2.5 emissions from stationary sources from 

2002 to 2009 because the 2002 inventory was based on emissions reported to the 

Department by facilities and did not include condensable PM for many facilities. The 

projected 2009 PM2.5 emissions for electric generating units (EGUs) include condensable

PM emissions which were calculated based on factors derived from AP-42 defaults.

2. Growth Projection Methodologies

This section describes the data, methods, and assumptions utilized in developing estimates 

of emissions changes between 2002 and the milestone year 2009. Appendix 

D-1 contains the technical support document entitled, Development of Emission 

Projections for 2009, 2012, and 2018 for Non-EGU Point, Area, and Nonroad Sources in 

the MANE-VU Region, developed by Mid-Atlantic Regional Air Management Association 
19

(MARAMA). The document provides details on the specific factors, control assumptions, 

and implementation schedules used in the emission projection calculations for each source 

category. 

Stationary Point Sources. For EGUs, the Department used the EPA’s Integrated 

Planning Model (IPM) modeling as adjusted by the Visibility Improvement State and 

Tribal Association of the Southeast (VISTAS), specifically VISTAS 2.1.9, to predict the 

results of the EPA’s CAIR at affected facilities throughout the CAIR region. The 

emissions for 2009 resulting from application of the CAIR cap and trade program for 

annual NOx emissions, as predicted by IPM, were used. IPM estimates NOx and SO2

emissions only. Operating parameters predicted by IPM for each EGU and emission 

factors were used to predict emissions of VOC, PM10, PM2.5, condensable PM, and NH3. 

The technical support documents that describe the methodologies used to project the 

emissions from EGUs, Documentation of 2018 Emissions from Electric Generating Units 

in the Eastern United States for MANE-VU’s Regional Haze Modeling (Alpine 

Geophysics, April 2008) and Future Year Electricity Generating Sector Emission 

Inventory Development Using the Integrated Planning Model (IPM®) in Support of Fine 

Particulate Mass and Visibility Modeling in the VISTAS and Midwest RPO Regions (ICF, 

April 2005) are included as Appendices D-2 and D-3, respectively.

For non-EGU point sources, the methodology for projecting emissions to 2009 is the same 

as the methodology described below for stationary area sources as documented in 

Appendix D-1, Development of Emission Projections for 2009, 2012, and 2018 for NonEGU Point, Area, and Nonroad Sources in the MANE-VU Region. This report was 

prepared for MARAMA as part of an effort to assist states in developing attainment plans 

for ozone and fine particles, and in developing regional haze plans. It describes the data 

sources, methods, and results for emission forecasts for three years, three emission sectors, 

two emission control scenarios, seven pollutants, and 11 states plus the District of 

Columbia. MARAMA developed projections for 2009, 2012, and 2018. 

The projected 2009 PM2.5 emissions for EGUs include condensable PM. Emissions of 

condensable PM were calculated based on factors derived from AP-42 defaults. Because 

the 2002 inventory was based on emissions reported to the Department by facilities and did 

not include condensables for many facilities, the emissions inventory shows an apparent 

increase in PM2.5 emissions from stationary sources from 2002 to 2009.

Area Sources. Area source emissions were projected from the 2002 inventory. 

The factors used for the temporal allocation of projections to 2009 from the 2002 baseline 

inventory were provided by MARAMA, which is coordinating air quality technical 

projects for the Northeast and Mid-Atlantic states. The factors were in the form of Sparse 

Matrix Operator Kernel Emissions (SMOKE) v2.2 input files6.

 

6 For additional information on the SMOKE file formats, please refer to the SMOKE v2.2 Users Manual, 

available from the Center for Environmental Modeling for Policy Development (CEMPD) at 

http://cf.unc.edu/cep/empd/products/smoke/index.cfm#Documentation.
20

A table of growth factors for 2009 was provided by MARAMA. For each state, county 

and SCC, this table includes state growth factors derived from the Energy Information 

Administration (EIA) Annual Energy Outlook, 2005; and/or factors extracted from the 

Economic Growth Analysis System (EGAS). Where more than one factor was available, 

the first choice was the EIA factor followed by the EGAS factor.

MARAMA also supplied tables of control factors, rule effectiveness factors, and rule 

penetration factors for any control measures applicable to these sources. 

For the area sources, these factors were available by SCC and pollutant. There may be 

more than one generic control factor that applies to a given SCC and pollutant. In cases 

where there was more than one applicable factor, the following formula may have been 

applied recursively to generate reductions that are a composite of those factors.

Emissions Emissions CF RE RP Emissions Controlled

Where

CF is the control factor

RE is the rule effectiveness factor

RP is the rule penetration factor

As described for stationary point sources above, Appendix D includes the MARAMA 

report, Development of Emission Projections for 2009, 2012, and 2018 for NonEGU 

Point, Area, and Nonroad Sources in the MANE-VU Region, which documents the 

methodology for projecting emissions to 2009.

Highway Vehicle Sources. The EPA’s approved highway vehicle emission model, 

MOBILE 6.2, projects highway vehicle average fleet emission factors. State specific 

information was used where available and appropriate. Traffic forecasts were 

compiled using information from PennDOT’s Traffic Information System and 

socioeconomic data. The Pennsylvania methodology for estimating highway vehicle 

emissions is consistent with the January 2002 guidance published by the EPA’s Office 

of Transportation and Air Quality (OTAQ) entitled, Technical Guidance on the Use of 

MOBILE6 for Emissions Inventory Preparation. Appendices E-1 through E-5 include

specific information on the highway emissions inventory methodology, data files of 

emissions estimates, MOBILE6.2 input parameters, a MOBILE6.2 sample input file, 

and the traffic growth forecasting system report.

As shown in Table III-3, VMT for the future analysis year increases 11% from 18.3 billion 

to 20.3 billion VMT within the nonattainment area. Despite the growth in VMT, emissions

of the most significant vehicle-related precursor, NOx, are significantly lower in the future 

analysis year.
21

Table III-3: Regional Nonattainment Area VMT and Emissions

Direct PM

YEAR VMT PM2.5 PM10 VOC NOx SO2 NH3

2002 18,322,527,954 824 1,164 25,638 53,268 1,770 1,884

2009 20,266,112,739 509 852 14,098 28,739 230 2,121

Nonroad Sources. Projected emissions for the majority of nonroad emission source 

categories and pollutants were estimated using the EPA NONROAD 2005 model, which 

contains default assumptions for projected years. The NMIM estimated future ammonia 

emissions from source categories in the NONROAD model. The NONROAD model and 

NMIM estimate emissions for diesel, gasoline, liquefied petroleum gasoline, and 

compressed natural gas-fueled nonroad equipment types and include growth factors. 

Future aircraft emissions from small and large airports were calculated by using future 

airport operation estimates, which can be found in the FAA’s Terminal Area Forecast 

Detailed Report. Emission factors from aircraft and the aircraft mix remained unchanged 

in future years. 

For locomotive emissions, the Department projected emissions from 2002 to 2009, using 

national fuel consumption data obtained from the Association of American Railroads and 

the EPA emission factors developed for the locomotive fleet in future years.

Commercial marine vessel emissions were grown using projected activity, fuel use and 

emission estimates from the EPA document, Final Regulatory Analysis: Control of 

Emissions from Marine Diesel Engines, November 1999.

Additional information about nonroad emission projection methodologies can also be 

found in Appendix F. Appendix F-1 is the technical document providing the methodology 

and description of the procedures used to generate 2002 and 2009 county-level pollutant 

emission estimates for nonroad mobile engines included in the EPA’s NONROAD2005 

model, locomotive engines and aircraft operations. The table of nonroad emissions data

sorted by source category is available as Appendix F-2.

D. Reasonable Further Progress (RFP) Requirements

Section 172(c)(2) of the CAA requires that plans for nonattainment areas provide 

reasonable further progress. In accordance with 40 CFR 51.1009, if a state submits an 

attainment demonstration for an area which demonstrates that the area will attain the PM2.5

NAAQS within five years of designation, the state is not required to submit a separate RFP 

plan. In that case, compliance with the emission reduction measures in the attainment 

demonstration and SIP will meet the requirements for achieving RFP for the area. This 

attainment demonstration and SIP revision demonstrate that the Pittsburgh-Beaver Valley 

Area will attain the PM2.5 NAAQS by the area’s attainment date of April 2010, which is 
22

within five years of designation. Therefore, compliance with the emission reduction 

measures described in this plan meets the requirements for achieving RFP for the area. 

E. Motor Vehicle Emission Budgets for 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-Beaver Valley 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. The information in Table III-5, once the EPA approves it for 

purposes of conformity, will establish transportation conformity budgets for the PittsburghBeaver Valley 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 of SOx, VOC, and NH3 were analyzed to determine if motor 

vehicle budgets should be established for these pollutants. Table III-4 illustrates the onroad mobile source fraction of the total 2009 inventory for each of these pollutants. VOC

and NH3 account for a total of 22.30 % and 32.93 % of the total projected 2009 inventory 

for VOC and NH3, respectively. Motor vehicle emissions of SOx account for 0.18 % of the 

total projected 2009 inventory.
23

Table III-4 Comparison of 2009 On-Road Mobile Precursor Emissions to the Total 

Projected 2009 Inventory

2009 SO2 VOC NH3

On-Road Mobile Source 

Projected Inventory (Tons) 230 14098 2121

Total Projected 2009 Inventory 

(Tons) 129074 63230 6440

Percent of Total Projected 2009 

Inventory (%) 0.18 22.30 32.93

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. As discussed earlier in Section I, the Commonwealth is not considering VOC 

or NH3 as PM2.5 precursors for the purpose of the attainment plan 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. As shown in Table III4, motor vehicle emissions of SO2 are a small percentage of the total inventory. Based on 

these facts and the fact that no applicable finding has been made for these pollutants, this 

SIP revision is only establishing motor vehicle emission budgets for direct PM2.5 and NOx, 

as shown in Table III-5.

Table III-5: Motor Vehicle Emission Budgets

2009 PM2.5 NOx

Tons/year 509 28739

The Department has included direct PM2.5 re-entrained road dust emissions from paved 

and unpaved roads in the area source inventory. However, a number of fugitive dust 

studies have indicated that the PM2.5 / PM10 ratios measured by EPA FRM samplers are 

significantly lower than predicted by AP-42 emission factors. As a result, the PM2.5

emission estimates using AP-42 are biased high by as much as a factor of two, compared to 

FRM samplers. The Department believes that the emissions from paved and unpaved 

roads are significantly over-predicted and, therefore, has not included those emissions in 

the motor vehicle emission budgets at this time. Appendix C-2, relating to area source 

annual emissions, contains estimates of the PM2.5 emissions attributable to paved and 

unpaved roads. 

Transportation construction-related fugitive dust emissions are not a significant contributor 

to the air quality problem. At the Pittsburgh-Beaver Valley Area speciation monitor, the 

crustal component was found to be small compared to other components of PM2.5 (see 
24

Section V, Figure 5). Given that construction-related fugitive dust is one of many source 

categories contributing to the crustal material observed at the monitor, and transportation 

construction is a small subset of all construction, it is safe to conclude that transportation 

construction-related fugitive emissions are insignificant. 
25

IV. CONTROL STRATEGIES

A. Permanent and Enforceable Control Measures

This section describes the federal and state measures that will provide the direct PM2.5, SO2

and NOx emission reductions leading to emission reductions and attainment of the 

standard. 

A summary of the quantity of emission reductions expected from 2002 to 2009 is included 

in Table IV-1. (Positive values indicate emission reductions, negative values indicate an 

increase in emissions.) The emission reduction estimates account for any anticipated 

growth in the activity of sources regulated by the strategy. For some pollutants and 

categories, emissions in 2009 are anticipated to be higher than they were in 2002. In those 

cases, projected growth in emissions is larger than anticipated emission reductions from 

control measures for that pollutant and source category. Each measure is explained in 

greater detail in the following sections.

Table IV-1: Summary of Emission Reductions 2002-2009 from Control Measures

2002-2009 Difference PM2.5 SO2 NOx

Stationary Point Sources -13292 348612 59257

Area Sources -212 -547 -479

Highway Vehicle Sources 315 1540 24529

Nonroad Sources 155 309 4729

1. Stationary Point Sources

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. The Court ordered the EPA to revise the CAIR 

consistent with the July 11, 2008 decision, but did not set a deadline. EPA intends to 

promulgate a replacement rule in 2011. In the meantime, CAIR is being implemented. 

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

market-based CAIR was designed to reduce large electric generation unit (EGU) emissions

of NOx and SO2 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. 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 
26

the EPA on May 23, 2008. EPA subsequently proposed approval of the Commonwealth’s 

CAIR SIP Revision on September 24, 2009 (74 FR 48695).

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). 

New Source Review Programs. The federal New Source Review (NSR) programs are 

preconstruction review and permitting programs applicable to new or modified major 

stationary sources subject to Title I, Parts C and D of the federal CAA. The programs

consist of the Prevention of Significant Deterioration (PSD) requirements, which are 

applicable in areas attaining the NAAQS, and the Nonattainment NSR requirements, which 

are applicable in geographic areas not attaining and maintaining the NAAQS. 

The Department’s PSD regulations, codified in 25 Pa.Code Chapter 127, Subchapter D, 

were approved by the EPA on August 21, 1984 and codified at 40 CFR § 52.2058 (49 FR

33128). The federal PSD regulations codified in 40 CFR Part 52 are incorporated by 

reference in their entirety in 25 Pa. Code § 127.83 (relating to adoption by reference). The 

PSD program requires any new source to implement Best Available Control Technology 

(BACT) and limits a new source's allowable impact on the environment. 

The EPA granted “limited” approval of the Department’s revised NSR regulations codified 

in 25 Pa.Code Chapter 127, Subchapter E, and published a final rule on December 7, 1997 

(62 FR 64722). On October 19, 2001, the EPA converted the limited approval to a “full”

approval for all areas of the Commonwealth except the five-county Philadelphia area 

(Bucks, Chester, Delaware, Montgomery, and Philadelphia counties) (66 FR 53904). 

Nonattainment NSR requirements include compliance with the lowest achievable emission 

rate and emission offsets.

These federally enforceable programs, incorporated in the Commonwealth’s SIP, 

will also reduce emissions to provide continued improvements.

Federal Standards for Hazardous Air Pollutants. Federal standards to control 

hazardous air pollutants (HAPs) require Maximum Achievable Control Technology 

(MACT) at units located at major sources of HAPs. The EPA has issued a series of 

regulations that are applicable to sources in Pennsylvania. These MACT standards are 

adopted and incorporated by reference in Section 6.6 of Pennsylvania’s Air Pollution 

Control Act and implementing regulations and are also included in federally enforceable 

permits issued by the Department for affected sources. Controls with a 2002 compliance 

date and earlier are included in the base year inventory for 2002, while controls with a 
27

compliance date of 2003 and later are included in the projection inventories. A list of the 

categories for which federal MACT standards have been issued is contained in Appendix

D-1.

Source Surveillance. Pursuant to 40 CFR Part 51, Subpart K (relating to source 

surveillance), the SIP revision is required to provide for monitoring of the status of 

compliance with any rules and regulations that set forth any portion of the control strategy. 

These include provisions, as applicable, for:

emissions reports and recordkeeping for stationary sources;

periodic testing and inspection of stationary sources;

enforcement and complaint investigation of visible emission limitations;

enforceable test methods for emission limits; and

continuous emission monitoring for stationary sources.

Subpart K also requires monitoring of the implementation of transportation control 

measures (TCMs). There are no TCMs in this SIP. 

After review, the Department finds that the rules and regulations for stationary sources,

which are part of the control strategy for attaining the PM2.5 standard, as well as the 

Department’s comprehensive permitting program requirements in 25 Pa. Code Chapter 127 

and the Commonwealth’s SIP in 40 CFR 52.2020, meet the requirements of Subpart K. 

2. Highway Vehicle Sources 

Even with increases in VMT that occur from 2002 through 2009, highway vehicle 

emissions will continue to decrease. As more vehicles subject to cleaner new car standards 

replace older vehicles subject to less stringent new vehicle standards, the fleet as a whole 

emits fewer emissions, compensating for the increase in vehicle miles traveled. These 

decreases can be attributed to the programs described below. 

Federal Motor Vehicle Control Programs (FMVCP) and Pennsylvania Clean Vehicle 

Program for passenger vehicles and light-duty trucks and cleaner gasoline. 

Tier 1 tailpipe standards established by the CAA Amendments of 1990 include NOx and 

VOC limits for light-duty gasoline vehicles (LDGVs) and light-duty gasoline trucks 

(LDGTs). These standards began to be phased in 1994. Evaporative VOC emissions were 

reduced in gasoline-powered cars starting with Model Year (MY) 1998.

In 1998, under the authority of section 177 of the CAA, the Department adopted the 

Pennsylvania Clean Vehicles Program (28 Pa. B. 5873, Dec. 5, 1998). The Pennsylvania 

Clean Vehicles Program incorporates by reference certain California Low Emission 

Vehicle (CA LEV) emission standards for passenger cars and light-duty trucks. As 

required under Section 177 of the CAA, these provisions are identical to the low emission 

standards adopted by California. The regulation does not incorporate by reference the 
28

California zero emissions vehicle (ZEV) or emissions control warranty systems statement 

provisions.

In the same rulemaking, the Department adopted the National Low Emission Vehicle 

(NLEV) program as a compliance alternative to the Pennsylvania Clean Vehicles Program. 

The NLEV program became effective in the Ozone Transport Region (OTR) in 1999. 

Pennsylvania’s New Motor Vehicle Emissions Control Program regulations in 25 Pa. 

Code Sections 126.401-126.441 allowed automobile manufacturers to comply with NLEV 

instead of the CA LEV program through MY 2005. These regulations affected vehicles 

6,000 pounds and less and were the regulations in effect for new motor vehicles in the 

baseline year, 2002. 

In 1999, the EPA promulgated regulations more stringent than NLEV (Tier 2), starting 

with MY 2004. In order to participate in NLEV, Pennsylvania had been required to adopt 

language that extended its “commitment” to NLEV until MY 2006. In practical terms, the 

NLEV program was replaced for MY 2004 and later by the more stringent Federal “Tier 2” 

vehicle emissions regulations, 65 FR 6698 (Feb. 10, 2000), and vehicle manufacturers 

operating under the NLEV program became subject to the Tier 2 requirements. 

Pennsylvania amended the former New Motor Vehicle Control Program (which included 

the Pennsylvania Clean Vehicles Program) in 2006. The Clean Vehicles Program 

continues to incorporate the California Low Emission Vehicle Program (CA LEV II) by 

reference. As amended, the program affects MY 2008 and newer passenger cars and lightduty trucks vehicles. 36 Pa. B. 7424 (Dec. 9, 2006). 

Emissions for milestone years were estimated based on compliance with the Pennsylvania 

Clean Vehicles Program according to the methodology described in section 7.4.1 of the 

Technical Guidance on the Use of MOBILE6.2 for Emissions Inventory Preparation

published by the EPA’s OTAQ in January 2002. This methodology is further explained in 

Appendix E. The Department is assuming in its MOBILE modeling that the federal Tier 2 

program applies to subject vehicles sold in Pennsylvania from MY 2004 through MY 2007 

and the Pennsylvania Clean Vehicles Program applies to subject vehicles sold in MY 2008 

and beyond.

Heavy-Duty Diesel Control Programs. The EPA promulgated more stringent national 

regulations for heavy-duty engines and vehicles (over 14,000 pounds) starting with MY

2004. In addition, consent decrees with seven of the largest heavy-duty engine 

manufacturers required, among other terms, that diesel engines made by these companies 

comply with these 2004 standards two model years early, in MY 2002. Pennsylvania 

includes these programs as provided in the MOBILE model. 

In 2002, the Department adopted the Heavy-Duty Diesel Emissions Control Program for 

model years starting after May 2004. The program incorporates California standards by 

reference and requires MY 2005 and subsequent new heavy-duty diesel highway engines 

to be those certified by California. California standards were more stringent than federal 

standards for the two model years between expiration of the consent decrees discussed 
29

above and the implementation of more stringent federal standards affecting MY 2007 and 

beyond. However, EPA’s MOBILE model already assumes that the engines would 

comply with consent decree standards, even without an enforcement mechanism. The 

Department has used MOBILE defaults to calculate emissions from MY 2005 and 2006 

highway engines.

The EPA adopted new emission standards for heavy-duty engines and vehicles for MY

2007 and subsequent. For diesel engines, the standards will be phased in from 2007 to 

2010 for NOx and VOCs. For gasoline engines, the standards will be phased in during 

MY 2008 and 2009. Federal and California standards are virtually identical for MY 2007. 

For MY 2008, California adopted requirements for idling restriction engine programming

and an optional “clean NOx idle” standard. However, there is no EPA-approved 

methodology to estimate emission reductions from this requirement. Therefore, the 

emission estimates use assumptions of the federal rule for MY 2007 through 2010.

Because the new engine standards are adversely affected by sulfur in fuel, the EPA also 

requires most highway diesel fuel to contain no more than 15 parts per million (ppm) of 

sulfur, beginning in the fall of 2006. There is a temporary compliance option allowing 

refiners to continue to produce up to 20 percent of their highway diesel fuel at 500 ppm 

fuel until 2010. The Department uses MOBILE defaults to estimate the effects of the 

phase-in provision.

Vehicle Emission Inspection/Maintenance Program. In early 2004, Pennsylvania 

revised the implementation of its Vehicle Emission Inspection/Maintenance (I/M) Program 

in the four applicable counties (Allegheny, Beaver, Washington, Westmoreland) in the 

Pittsburgh-Beaver Valley Area. The program applies to gasoline-powered vehicles 9,000 

pounds and under, MY 1975 and newer. For vehicles MY 1996 and newer, the program 

consists of an annual on-board diagnostics test and a gas cap pressure test. For subject 

vehicles MY 1995 and older, the program consists of an annual two-speed idle test, visual 

inspection of pollution control devices to ensure they are present, connected and the proper 

type for the vehicle and a gas cap pressure test. For vehicles older than 25 years, the 

program is a visual inspection and gas cap test. These regulations can be found in 67 Pa. 

Code Chapter 177. Pennsylvania submitted the revised emissions program as a SIP 

revision on December 1, 2003. The EPA approved the SIP revision on October 6, 2005.

(70 FR 58313).

Low sulfur gasoline. Simultaneously with the Tier 2 program, the EPA published a 

regulation requiring the reduction of sulfur in gasoline beginning in 2004, with full 

implementation in 2006. Sulfur levels are capped at 80 ppm per gallon and annual refinery 

averages must be no more than 30 ppm. The emission reduction analysis uses the default 

assumptions provided in MOBILE6 to account for the implementation of the federal sulfur 

standard rule. 

Diesel Vehicle Idling Restrictions. On October 9, 2008, Governor Rendell signed the 

Diesel-Powered Commercial Motor Vehicle Idling Act (Act 124 of 2008). Act 124 of 

2008 went into effect on February 6, 2009. This Act restricts subject drivers and owners 
30

statewide from idling a diesel-powered motor vehicle engaged in commerce with a gross 

vehicle weight of 10,001 pounds or more for more than five minutes in any continuous 60-

minute period. Also, no owner or operator of a location where the aforementioned vehicles 

load, unload or park may allow the vehicles to idle for more than 5 minutes in a 60-minute 

continuous period. Act 124 of 2008 specifically excludes some vehicles, such as motor 

homes and farm vehicles used in farm applications. Additional exemptions are allowed for 

certain vehicles being used in specific applications. Truck drivers may idle sleeper-berth 

equipped vehicles for the purposes of long duration travel rest if the temperature is 

extremely hot or cold. In May 2010, this temperature exemption expires. A properly 

labeled “low-NOx idle” engine may idle for an unlimited amount of time. 

Act 124 of 2008 will be enforced by Department personnel, and by state and local law 

enforcement personnel. The law preempts and supersedes local ordinances, although rules 

in Allegheny County and Philadelphia County that are determined by those counties to be 

more stringent than the law may remain in effect. The Department estimates that 50 

percent of all long duration idling for Class 8 trucks will be eliminated in 2010 when the 

temperature exemption for sleeper 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. Emission reductions expected from this strategy are not included in the 

projected emissions inventory for 2009 since a period of compliance assistance and 

education is expected during that year Act 124 of 2008 will be submitted to EPA for 

approval as a revision to the Commonwealth’s SIP by the end of 2009.

3. Nonroad Sources 

The EPA has adopted a series of regulations affecting new diesel-powered (“compression 

ignition”) and gasoline-powered (“spark ignition”) nonroad engines of various sizes 

(horsepower) and applications. Information on these federal rules, including their 

implementation dates, can be found at www.epa.gov/nonroad. The Department used the 

assumptions built into the nonroad model (NONROAD2005) to estimate emissions for all 

milestone years.

No new national or international regulations are expected to be applicable to aircraft by the 

attainment date. While the EPA has published a notice of proposed rulemaking for more 

stringent standards for locomotives and large commercial marine diesel engines, the 

agency has not finalized any new standards.

The EPA will also require diesel fuel used in most nonroad applications to contain less 

sulfur. The sulfur will prevent damage to the more advanced emission control systems 

needed to meet the engine standards; it will also reduce fine particulate emissions from 

diesel engines. In 2007, fuel sulfur levels were limited to 500 ppm for nonroad 

applications other than ocean-going marine vessels. In 2010, fuel sulfur levels will be 

reduced to the same sulfur concentration as in highway fuel, 15 ppm; this requirement 

applies in 2012 to locomotive and marine diesel fuel.
31

B. Reasonably Available Control Measures/Reasonably Available Control 

Technology Analysis

Section 172(c) of the CAA requires states to “provide for implementation of all reasonably 

available control measures (RACM) as expeditiously as practicable.” The regulatory 

requirement for RACM and reasonably available control technology (RACT) for PM2.5 SIP 

revisions is codified in 40 CFR 51.1010: “For each PM2.5 nonattainment area, the state 

shall submit with the attainment demonstration a SIP revision demonstrating that it 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.”

The EPA states in the Clean Air Fine Particle Implementation Rule preamble that it 

encourages states to conduct multi-pollutant analyses for PM2.5 and ozone to cull out 

potential RACM: 

“They can also try to use consistent meteorological fields and emissions inventories so 

that the same control strategies are relatively easy to evaluate for both ozone and PM2.5. 

Modeling the same future year(s) for PM2.5 and ozone can also make it easier to evaluate 

the impacts of controls on both pollutants. It should be noted that there are no specific 

modeling requirements other than the recommendation to try to harmonize the ozone, 

PM2.5, and regional haze analyses whenever possible.”7

The Commonwealth participated in two such collaborative processes with other states in 

the region. First, the OTC states formed a workgroup to identify and evaluate candidate 

control measures. Working from a preliminary list of approximately 1,000 potential 

control measures, the workgroup identified and analyzed 30 candidate control measures. 

Appendix G-1 contains the OTC report entitled, Identification and Evaluation of 

Candidate Control Measures, Final Technical Support Document (MACTEC, Feb. 2007).

The initial list of control measures considered is available as Appendix G-2. Based on the 

OTC Workgroup analysis, the Commissioners recommended that States consider emission 

reductions from the following source categories:

• Consumer Products

• Portable Fuel Containers

• Adhesives and Sealants Application

• Diesel Engine Chip Reflash

• Cutback and Emulsified Asphalt Paving

• Asphalt Production Plants

• Cement Kilns

• Glass Furnaces

• Industrial, Commercial, and Institutional (ICI) Boilers

• Regional Fuels

 

7. 72 FR 20609.
32

• Electric Generating Units (EGUs)

The final report, included as Appendix G-1, contains more detailed information about the 

process and includes tables summarizing the emission reduction potential of each control 

measure by source category and projection year. There are five subsections discussing the 

control measure and emission reductions for the five source category sectors: non-EGU 

point sources, area sources, EGUs, onroad mobile sources, and nonroad mobile sources. 

The Department also participated in an assessment of control measures for pollutants and 

sources affecting visibility through the MANE-VU regional haze planning process. As 

part of this effort, MANE-VU developed a list of possible control measures for 

consideration. The following categories were selected for analysis:

Coal and oil-fired EGUs

Point and area source industrial, commercial and institutional boilers

Cement kilns

Lime kilns

The use of heating oil

Residential wood combustion and open burning

Appendix G-3 contains the final report entitled, Assessment of Reasonable Progress for 

Regional Haze in MANE-VU Class I Areas (MACTEC, July 2007) from the MANE-VU 

control measure assessment project. This report presents the results of an analysis of the 

economic and environmental impacts of the potential control scenarios that could be 

implemented by MANE-VU states to reduce emissions from selected source categories in 

order to make reasonable progress toward meeting visibility improvement goals. 

As required under 40 CFR 51.1010, a SIP revision for a PM2.5 nonattainment area must 

demonstrate that all RACM, including RACT for stationary sources, necessary to 

demonstrate attainment as expeditiously as practicable have been adopted. The cumulative 

impact of implementing available measures must be considered in determining whether a 

particular emission reduction measure or set of measures is required to be adopted as 

RACM. 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. As discussed earlier in this document,

the Pittsburgh-Beaver Valley Area expects to monitor attainment at the end of 2009. 

Therefore, any RACM measures would need to be in effect in 2008.

The Department determined that there were no additional control measures that could be 

adopted by January 1, 2008. In addition, existing measures and those planned for 

implementation by 2009 are expected to enable the Pittsburgh-Beaver Valley Area to attain 

the 1997 PM2.5 NAAQS. Therefore, no further actions on RACM or RACT are warranted.

Although the measures explored by the OTC and MANE-VU workgroups are not required 

as RACM, many are worthwhile measures that Pennsylvania is currently pursuing. Others 

are measures that Pennsylvania may consider for the future.
33

C. Other Measures - VOC Control Measures

Although VOC is not a regulated PM2.5 precursor for the Pittsburgh-Beaver Valley Area, 

several VOC control measures are discussed in this section because they are included in 

the modeling associated with this attainment demonstration. 

Portable Fuel Containers. The Department adopted a portable fuel container regulation, 

25 Pa. Code Chapter 130, Subchapter A, to address VOC loss resulting from permeation 

through portable gasoline containers, evaporative loss through container openings, and 

spillage during the filling of small tanks on machines such as lawn mowers, chain saws

and jet skis. The regulation was submitted to the EPA as a SIP revision on March 26, 2003 

and approved on December 8, 2004 (69 FR 70893).

Consumer Products. This regulation applies statewide to any person who sells, supplies, 

offers for sale, or manufactures certain consumer products on or after January 1, 2005, for 

use in the Commonwealth. The program is contained in 25 Pa. Code Chapter 130, 

Subchapter B. It was submitted to the EPA as a SIP revision on March 26, 2003 and 

approved on December 8, 2004 (69 FR 70895). Additional regulations were adopted on 

October 11, 2008 and submitted to the EPA as a SIP revision on April 14, 2009.

Architectural and Industrial Maintenance (AIM) Coatings. The Pennsylvania AIM 

Coatings regulation applies statewide to any person who supplies, sells, offers for sale, or 

manufactures, blends or repackages an AIM coating for use within the Commonwealth, as 

well as a person who applies or solicits the application of an AIM coating within the 

Commonwealth. The AIM coating program requirements are specified in 25 Pa. Code

Chapter 130, Subchapter C. The regulation was submitted to the EPA as a SIP revision on 

December 3, 2003, with a supplement submitted on October 19, 2004. The EPA approved 

the provisions as an element of the SIP on November 23, 2004 (69 FR 69080).
34

V. ATTAINMENT DEMONSTRATION AND WEIGHT OF EVIDENCE (WOE) 

A. Attainment Demonstration Background and Objectives

The EPA issued fine particle standards in 1997 after evaluating hundreds of health studies 

and conducting an extensive peer review process. The 1997 annual health-based standard 

for PM2.5 is 15.0 μg/m3, based on the 3-year average of annual mean PM2.5 concentrations. 

The EPA also established a 24-hour health-based standard of 65 μg/m3, determined by the 

3-year average of the 98th percentile of 24-hour concentrations. The EPA set levels to 

protect the environment at the same levels as it set the health-based standards. Note that 

while the EPA has subsequently revised the 24-hour standard in 2006 to be more 

protective, EPA designated the Pittsburgh-Beaver Valley Area as nonattainment because it 

violated the 1997 annual standard of 15.0 μg/m3 based on 2001-03 monitoring data. 

Therefore, this SIP revision compares air quality data to the 1997 24-hour standard (65 

μg/m3).

On April 1, 2003, the EPA issued a memorandum, “Designations for the Fine Particle 

National Ambient Air Quality Standards” outlining the schedule for designating areas 

under the PM2.5 standard and related guidance on nine factors to consider in identifying 

nonattainment areas. The CAA provides for states and tribes to submit designation 

recommendations to the EPA, and it requires the EPA to provide time for consultation in 

cases where the Administrator plans to promulgate a designation that modifies the state or 

tribal recommendation. On December 17, 2004, the EPA published its air quality 

designations and classifications for the 1997 PM2.5 NAAQS. These designations became 

effective on April 5, 2005.

Figure 4 graphically depicts all of the PM2.5 nonattainment areas within Pennsylvania. The 

Pittsburgh-Beaver Valley Area currently violates the EPA’s annual PM2.5 standard (15.0 

μg/m3). The maximum 2008 annual design value in the area is 15.5 μg/m3. All monitors 

within the Pittsburgh-Beaver Valley Area are currently in attainment of the 1997 24-hour 

PM2.5 standard (65 μg/m3). The maximum 2008 24-hour design value in the area is 40

μg/m3. The Pittsburgh-Beaver Valley Area is required to attain the PM2.5 standard no later 

than five years from the effective date of designation of April 5, 2005 (April, 2010).

The purpose of the attainment demonstration is to ensure, through grid modeling, that 

projected emissions (with controls) will not cause the nonattainment area to exceed the 

1997 PM2.5 NAAQS. A complex grid model was run and processed over the entire 

Northeast to determine if the Pittsburgh-Beaver Valley Area would attain the PM2.5 

standard by April 5, 2010.

The procedures followed in this modeling analysis are in accordance with 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 (EPA-454/B-07-002, April 2007). A brief 

summary of the modeling analysis used in this demonstration is included in the following 

sections. The Department submitted a modeling protocol to the EPA in October 2007 for 
35

the Pittsburgh-Beaver Valley Area that includes a more thorough description of the 

modeling analysis. 

Figure 4: Pennsylvania’s PM2.5 Nonattainment Areas

B. Pittsburgh-Beaver Valley Area Conceptual Model Description

This section provides a brief description of the conceptual model for the Pittsburgh-Beaver 

Valley Area. The conceptual model was based on information from the Northeast States 

for Coordinated Air-Use Management (NESCAUM) final report entitled The Nature of the 

Fine Particle and Regional Haze Air Quality Problems in the MANE-VU Region: A 

Conceptual Description (2006) and the Department’s modeling protocol documentation 

(October 2007).
36

Fine particulate formation in the eastern United States is a complex process involving local 

and regional meteorology, topography, chemistry and transport. Since a violation of an 

annual standard potentially involves a large range of conditions throughout the year, it is 

difficult to determine a direct cause-and-effect relationship for such a violation. Violations 

of the annual standard ensure a large range of conditions will contribute to nonattainment 

making direct cause-and-effect relationships difficult to determine. In general, the 

following statements can be used to provide a working conceptual model that describes the 

annual PM2.5 nonattainment problem in the Pittsburgh-Beaver Valley Area:

Secondary fine particulate formation is a major contributor to annual PM2.5 

nonattainment in the Pittsburgh-Beaver Valley Area. Sulfates, organic carbon and 

nitrates make up approximately 75% of the annual fine-particulate concentrations

(see Figure 5).

Fine-particulate chemistry favors sulfate formation during the warm summer 

months and nitrate formation during the colder winter months.

In the summer time, large high pressure systems create favorable conditions for the 

oxidation of SO2, which eventually forms sulfates. These sulfates then contribute 

to episodes of high particulate concentrations.

In the winter time, local temperature inversions concentrate emissions near the 

surface leading to periods of elevated fine-particulate concentrations. This is 

especially apparent if significant terrain features are present.

Continuous measurements in the Pittsburgh-Beaver Valley Area correlate well with 

the FRM data. This indicates measurements from the continuous monitor generally 

reflect actual concentrations in the nonattainment area.

Average concentrations from the continuous monitor show a general diurnal pattern 

with higher concentrations in the overnight and early morning hours than during 

the day due to atmospheric conditions and possibly local mobile source emissions

(peaks during rush hour traffic, etc).

In addition to the diurnal signal noted in the continuous monitoring data there is a 

strong weekly pattern in the continuous monitoring data with higher PM2.5

concentrations on weekdays than on weekends.

A range of control measures will be necessary to attain the PM2.5 standard in the 

Pittsburgh-Beaver Valley Area due to the complex interaction between local and regional 

emissions and local meteorological conditions. Sulfates and nitrates are formed primarily 

through atmospheric reactions of precursor emissions of SO2, NOx and NH3. Organic 

carbon is a combination of secondary organic particles formed from emissions of VOC and 

the organic portion of primary PM2.5 that is directly emitted or condenses near its source. 

Currently, our understanding of sulfate and nitrate chemistry and its impacts on PM2.5

concentrations far exceeds our understanding of contributions from anthropogenic VOCs. 

This is important because sulfates, nitrates and organic carbon are major contributors to the 

fine particulate problem in the Pittsburgh-Beaver Valley Area. Therefore, it is reasonable 

to assume that a mixture of regional and local SO2 and NOx controls in addition to VOC 

controls implemented for attainment of the 8-hour ozone standard will assist in attaining

the PM2.5 standard.
37

Figure 5: Pittsburgh-Beaver Valley Area Percentage of Total Mass

Based on Speciated PM2.5 Data Collected at Lawrenceville

Averaged 2005 to 2007 Monitored Values

C. Modeling Domain and Photochemical Modeling System

The modeling demonstration for the Pittsburgh-Beaver Valley Area relies heavily on the 

OTC SIP quality-modeling platform. Ozone modeling was the primary focus of this effort. 

OTC’s interaction with MANE-VU and NESCAUM allowed it, through the regional 

modeling centers, to do additional year-round modeling for PM2.5 and Regional Haze.

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 (EPA-454/B-07-002, April 

2007) does not recommend a particular model or models for use in a SIP attainment 

demonstration. The OTC modeling committee used the CMAQ photochemical grid model 

(version 4.5) as part of its SIP modeling platform (OTC Final Modeling Protocol, 2006). 

CMAQ is an Eulerian grid model capable of simulating air pollutant concentrations in the 

atmosphere using mathematical equations to characterize chemical and physical properties.

Meteorological and emission input files must be prepared regardless of which 

photochemical grid model is used. The regional fine particulate modeling analysis 

encompassed an entire year of simulation for the year 2002. This approach provided a 

good variety of episodes to characterize the Pittsburgh-Beaver Valley Area’s PM2.5 

nonattainment problem.

Figure 6 shows the modeling domain used by the OTC Modeling Workgroup. A nestedgrid approach was used with the lower resolution outer grid providing boundary conditions 
38

for a more refined grid covering the area of interest. The modeling domain was chosen to 

be large enough to properly simulate regional transport. The outer domain boundary is far 

enough from the inner grid’s boundary so that clean-boundary condition assumptions along 

the outer domain’s boundary are realistic and probably do not unduly influence 

concentrations within the inner domain.

Figure 6. OTC Modeling Study Domain

Outer grid at 36-kilometer resolution, inner grid at 12-kilometer resolution

The meteorological files used in CMAQ were produced using the Pennsylvania State 

University/National Center for Atmospheric Research (PSU/NCAR) Mesoscale Model 

version 5 (MM5). MM5 is a limited-area, nonhydrostatic, terrain-following sigmacoordinate model designed to simulate or predict mesoscale atmospheric circulation. The 

model is publicly available and has been used for various air quality modeling studies in 

the past.

The OTC Modeling Committee also examined two emissions processors (EMS2001 and 

SMOKE, both using CB4 chemistry) in its prior work and concluded that there are 

differences between them that could be minimized by forcing the models to use a common 

speciation and surrogate database.

For areas with an attainment date of no later than April 5, 2010 for the PM2.5 NAAQS, the 

emission reductions need to be implemented no later than the beginning of 2009. A 

determination of attainment will be based on air quality monitoring data collected in 2007, 

2008, and 2009. Therefore, the year to project future emissions should be no later than the 

last year of the three-year monitoring period, which in this case is 2009.

The emissions inventory was developed for 2009 using standard emissions projection 

techniques. The 2009 inventories developed by MANE-VU were used in the attainment 
39

demonstration. The most recently available inventories from other regional planning 

organizations (RPOs) in the modeling domain were also used.

Emission inventory guidance documents were followed for developing projection year 

inventories for point, area, mobile, and biogenic emissions. These procedures address 

projections of spatial, temporal, and chemical composition change between the base year 

and projection year.

The control strategies developed for evaluation in the attainment demonstration were

selected by the OTC’s Control Strategy Committee. These were selected from groups of 

strategies developed by the technical subcommittees responsible for identifying and 

developing the regulations and/or other control measures.

Consideration was given to maintaining consistency with control measures likely to be 

implemented by other modeling domains that may be involved in region-wide analysis. 

Also, technology-based emission reduction requirements mandated by the CAA are

included in the future year model runs. 

D. Model Performance Evaluation

A critical component of every air quality modeling study is the model performance 

evaluation where modeled estimates for the current year base case are compared against 

observed values to assess the model’s accuracy and provide an indication of its reliability. 

The results presented here serve as an illustration of some of the model evaluation and 

assessment, as outlined in the EPA modeling guidance document entitled, Guidance on the

Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for 

Ozone, PM2.5, and Regional Haze (EPA-454/B-07-002, April 2007), performed on the 

Base Year 2002 CMAQ simulation.

The New York State Department of Environmental Conservation (DEC), Division of Air 

Resources, conducted a performance evaluation of the 2002 base case CMAQ simulation 

on behalf of the OTC member states. Model performance was evaluated over the entire 

year, except for the July 6-9, 2002 period which was excluded from this analysis since the 

observed PM2.5 and organic mass (OM) data at many sites were greatly affected by 

Canadian forest fires. Appendix H, relating to Modeling Demonstration, provides 

comprehensive operational and diagnostic evaluation results. Highlights of this evaluation 

are provided in the following sections. The analysis examines model performance over a 

wide area, including the entire OTR plus the State of Virginia (OTR+).

1. Daily PM2.5 Mass

Model performance over the entire OTR+ region was examined using several statistics. 

These included overall mean fractionalized bias (MFB) and mean fractional error (MFE). 

Equations for these diagnostics are summarized below and are included in the EPA

modeling guidance document entitled, Guidance on the Use of Models and Other Analyses 
40

for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze

(EPA-454/B-07-002, April 2007).

Mean fractionalized bias (MFB), in %:

MFB

N

P O

P O

i i

i i

2

100%

Mean fractional error (MFE), in %:

MFE

N

P O

P O

i i

i i

2

100%

where P = Predicted (modeled) value, O = Observed value, and N = 

Number of observations

Figures 7 and 8 show MFE and MFB over the entire OTC+ region. The figures indicate 

the model is generally doing a reasonable job reproducing PM2.5 across the entire domain 

with the exception of the New York City area and a few monitors in New England. 

Overall, the mean bias (predicted minus observed) was about 3.8 g m

-3

, ranging from -

17.7 g m-3to +24.0 g m-3. The highest over-prediction tended to occur during the colder 

months, quarters 1 and 4, whereas the days on which the model tended to under-predict 

PM2.5 were more likely to occur during the summer months.

Figure 7: Mean Fractional Error

MFE (%) at each FRM location over the entire year: blue, <30%; green, 30-45%; orange, 

45-60%; red, 60-75%; pink, >75% (From NY DEQ report, 2007).
41

Figure 8: Mean Fractional Bias 

MFB (%) at each FRM location over the entire year: gray, <-45%; blue, -45 to -15%; 

green, -15 to 15%; orange, 15-45%; red, 45-75%; pink, >75% (From NY DEQ report, 

2007).

2. PM2.5 Speciation

PM2.5 is composed of several components. The primary components noted in the 

monitoring data include sulfates, nitrates and organic carbon; other components do not 

significantly contribute to PM2.5 concentrations. For proper performance, CMAQ 

predictions for each individual component of PM2.5 must also be examined. 

Data from the various speciation networks in the OTR+ region were compared to model 

predicted values for the base case (2002). Again, data from the July 6-9, 2002 period was 

excluded from this analysis due to the Canadian forest fires.

Sulfates (SO4

-

) are one of the primary contributors to the Pittsburgh-Beaver Valley Area’s 

PM2.5 nonattainment. Figure 11 depicts modeled and actual sulfate measurements in the 

OTR+ region. The CMAQ model appears to reproduce actual sulfate concentrations quite 

well along with its seasonal variability.

Nitrates (NO3

-

) are another important contributor to the Pittsburgh-Beaver Valley Area’s 

PM2.5 nonattainment. CMAQ does less well reproducing actual concentrations than it does

for sulfates. Modeled concentrations appear to be less accurate during the colder months 

(1st and 4th quarters) than the warmer months.
42

OM is another important contributor to the Pittsburgh-Beaver Valley Area’s PM2.5

nonattainment. CMAQ does not do well reproducing the seasonal variability of OM

though it does appear to do a better job reproducing observed winter values.

Figure 9: Time Series of SO4 Mass 

Time series of SO4 mass based on the composite average of all 21 IMPROVE monitors 

across the OTR+ region. The observed values are denoted with the black diamonds, the 

model predictions are denoted with gray squares (From NY DEQ report, 2007).

NY DEQ’s model performance included an analysis of the meteorological model used to 

drive CMAQ, as well as actual PM2.5 values and PM2.5’s speciated components. Appendix 

H-2 is a technical listing of the model inputs, as well as an assessment of the MM5 

simulation to real-world data. The analysis shows that, in general, the performance of the 

MM5 is reasonable both at the surface and in the vertical, thereby providing confidence in 

the use of these data in the CMAQ simulations.

Both the MM5 and CMAQ runs appear to meet performance criteria over the entire OTR+ 

domain. Therefore, it can be assumed the modeling platform provides meaningful 

information in regard to projected 2009 PM2.5 concentrations that will be used to assess the 

Pittsburgh-Beaver Valley Area’s future attainment of the PM2.5 standard.
43

E. Projected 2009 Design Values for the Pittsburgh –Beaver Valley Nonattainment 

Area

1. Overview

As mentioned previously, the Pittsburgh-Beaver Valley Area has an attainment date of 

April 5, 2010. The PM2.5 NAAQS include an annual standard of 15.0 μg/m3based on the 

3-year average of annual mean PM2.5 concentrations, and a 24-hour standard of 65 μg/m3

based on the 3-year average of the 98th percentile of 24-hour concentrations.

This section summarizes the procedures that are used to demonstrate attainment of the 

PM2.5 NAAQS. As described in 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 (EPA-454/B-07-002, April 2007), an attainment demonstration consists of 

(a) analyses that estimate whether selected emissions reductions will result in ambient 

concentrations that meet the NAAQS, and (b) an identified set of control measures that 

will result in the required emissions reductions. The necessary emission reductions for 

both of these attainment demonstration components may be determined by relying on 

results obtained with air quality models.

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 (EPA-454/B-07-002, April 

2007) recommends applying a modeled attainment test to the air quality modeling results 

to determine if the PM2.5 NAAQS will be met. Additional technical or corroboratory 

analyses may also be used as part of a “supplemental analysis” or a more stringent “weight 

of evidence” determination to supplement the modeled attainment test and to further 

support a demonstration of attainment of the NAAQS.

The modeled attainment test and additional corroborative analyses are described in further 

detail in the remaining portions of this section.

2. Modeled Attainment Test

The purpose of a modeling assessment is to determine if control strategies currently being 

implemented “on the books” (OTB) and proposed control strategies will lead to attainment 

of the NAAQS for PM2.5 by the attainment year of 2009. The modeling is applied in a 

relative sense, similar to the 8-hour ozone attainment test: however, the PM2.5 attainment 

test is more complicated and reflects the fact that PM2.5 is a combination of many different 

species. In the test, ambient PM2.5 is divided into major components. Then, a relative 

response factor (RRF) and future design value (DVF) is calculated for each of the PM2.5 

components. Since the attainment test is calculated on a per species basis, the attainment 

test for PM2.5 is referred to as the Speciated Modeled Attainment Test (SMAT). The 

following sections outline the process to determine that 2009 projections of PM2.5 will 

meet the NAAQS from regional modeling, as suggested in EPA’s modeling guidance.
44

3. Determine Baseline Design Values

The first step in any attainment test process is to determine the baseline design value 

(DVB). The EPA guidance recommends using a DVB that is the average of the three 

design value periods that straddle the baseline inventory year (i.e., the average of the 2000-

2002, 2001-2003, and 2002-2004 design value periods for a 2002 baseline inventory year). 

This results in a 5-year weighted average, with the baseline year having the heaviest 

weight (i.e., {[2000] + 2*[2001] + 3*[2002] + 2*[2003] + [2004]}/9). 

For the SMAT process, a mean PM2.5 DVB is determined, as well as component specific 

DVB, for each quarter. The following section will detail the calculation of baseline design 

values needed for the PM2.5 attainment test.

Mean PM2.5 Baseline Design Values

To begin the SMAT process, a mean PM2.5 DVB is calculated on a quarterly basis for each 

FRM monitor in the PM2.5 nonattainment areas. Concentrations are calculated based on 

calendar quarters (Q1: January - March; Q2: April - June; etc.) as the NAAQS is calculated 

for a calendar year, and the quarters need to fit evenly within a year. Calculating the 

attainment test on a quarterly basis also allows states to examine the differences in PM2.5 

composition that occur during the different seasons.

Speciated Baseline Conditions

The monitored attainment test for PM2.5 utilizes both PM2.5 and individual PM2.5 component 

species. A separate RRF is calculated for each PM2.5 species. In order to perform the 

recommended modeled attainment test, states should divide observed mass concentrations 

of PM2.5 into seven components (plus passive mass):

1. Mass associated with sulfates (SO4)

2. Mass associated with nitrates (NO3)

3. Mass associated with ammonium (NH4)

4. Mass associated with organic carbon (OC)

5. Mass associated with elemental carbon (EC)

6. Mass associated with particle bound water (PBW)

7. Mass associated with “other” primary inorganic particulate matter (Crustal)

8. Passively collected mass or the mass of the blank filter (Passive)

This yields the following formula in order to calculate PM2.5:

PM2.5FRM = [SO4] + [NO3] + [OC] + [EC] + [NH4] + [PBW] + [Crustal] + [Passive]

The second part of the process is to use the quarterly mean PM2.5 DVBs with speciated data 

to calculate the quarterly mean concentrations of these 7 components at the FRM sites. 

This need to speciate the FRM data presents two issues: 
45

1. FRM measurements and speciated PM2.5 measurements do not always measure the 

same mass. 

2. Not all FRM monitoring sites have co-located Speciation Trends Network (STN)

speciation monitors. 

The following sections will explain how these issues are addressed to produce the 

speciated values needed for this attainment demonstration.

SANDWICH

As 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 (EPA-454/B-07-

002, April 2007) notes, recent data analyses have noted that the FRM monitors do not 

measure the same components and do not retain all of the PM2.5 that is measured by STN 

samplers. Therefore, measurements from FRM monitors cannot be directly compared to 

speciation measurements from the STN monitors. By design, the FRM mass measurement 

does not retain all ammonium nitrate and other semi-volatile materials (negative sampling 

artifacts) and includes particle bound water associated with sulfates, nitrates and other 

hygroscopic species (positive sampling artifacts). This results in concentrations (and 

percent contributions to PM2.5 mass) that may be different from the ambient levels of some 

PM2.5 chemical constituents. 

To resolve the differences between FRM and STN total mass, EPA recommends using the 

“sulfate, adjusted nitrate, derived water, inferred carbonaceous” (SANDWICH) material 

balance approach. With the SANDWICH approach, nitrate mass is adjusted to account for 

volatilization based on hourly meteorology parameters. Subsequently, quarterly average 

nitrate, sulfate, elemental carbon, ammonium and crustal mass can be calculated, as well as 

the Degree of Neutralization (DON) of sulfates. Next, the mass of particle bound water 

can be calculated from the previously obtained DON, sulfate, nitrate, and ammonium 

values. (See more details on particle bound water calculations in the Annual SMAT 

Results section, below). Finally, organic carbon is calculated by taking the difference 

between the total PM2.5 mass as measured at the FRM monitor, and the calculated 

component mass (i.e., OC from mass balance ([OCMmb] = PM2.5FRM - {[EC] + [SO4] + 

[NO3] + [NH4] + [PBW] + [Crustal] + [Passive]}), where the Passive (mass) is the FRM 

sampling artifact normally set equal to 0.5). 

EPA Region 3 office provided SANDWICHed data for the Pittsburgh-Beaver Valley Area

monitors. For a description and use of the SANDWICH method, see the Definition of 

SANDWICHed STN Data (EPA, 2006).

Speciated Profiles

While the SANDWICH method reconciles the differences between FRM and STN, a 

lingering issue is that not all FRM monitoring sites have co-located STN monitors to 

provide speciated data. EPA guidance suggests four measures that can be taken to resolve 

the lack of speciated data: 
46

1. Use of concurrent data from a nearby speciated monitor

2. Use of representative data (from a different time period)

3. Use of interpolation techniques to create a spatial field using ambient speciation 

data

4. Use of interpolation techniques to create spatial fields, and gridded modeling 

outputs to adjust the species concentrations

Of the four methodologies, EPA recommends using one of the spatial interpolation 

techniques to estimate species concentrations at FRM sites that do not have speciation data 

(numbers 3 and 4, above). To assist in this task, EPA began developing a software tool 

called “Modeled Attainment Test Software” (or MATS) that would perform the spatial 

analysis of described options number 3 and 4. However, the MATS tool was not available 

at the time this analysis was completed. In trying to pursue the EPA recommended course 

of action, option 1 (use of concurrent data from a nearby speciated monitor) was utilized.

4. Relative Response Factor Calculations

The calculation of RRFs for this study was performed using the EPA recommended 

method for “nearby” grid cells for a 12-kilometer horizontal grid resolution, with a 3x3 

grid cell array for 12-km resolution modeling. The relative response factor used in the 

modeled attainment test is computed by taking the ratio of the mean of the predictions in 

the future to the mean predictions with baseline emissions, over all relevant days.

For the 24-hour and annual PM2.5 NAAQS, the spatially averaged value of the nearby 

predictions (mean value of the grid cell array) was used. Each component-specific RRF 

was used in the modeled attainment test by taking the ratio of the mean of the spatially 

averaged daily predictions in the future to the mean of the spatially averaged daily 

predictions with current emissions.

The basis for this approach is as follows:

1. Consequence of a control strategy may be “migration” of a predicted peak. If a 

state were to confine its attention only to the cell containing a monitor, it might 

underestimate the RRF (i.e., overestimate the effects of a control strategy).

2. Uncertainty in the formulation of the model and the model inputs is consistent with 

recognizing some leeway in the precision of the predicted location of 

concentrations.

3. Standard practice in defining a gridded modeling domain is to start in the southwest 

corner of the domain and determine grid cell location from there. Considering 

several cells “near” a monitor rather than the single cell containing the monitor 

diminishes the likelihood of inappropriate results that may occur from the geometry 

of the superimposed grid system.

4. The area does not exhibit strong spatial concentration gradients of observed 

primary PM2.5.
47

5. Annual SMAT Results

A difficulty presented in estimating the future design values was missing STN data for 

2000 and 2001at the Pittsburgh-Beaver Valley Area monitors. This limitation restricted 

the calculation of SANDWICH data to the period 2002–2004. Therefore, the 2009 

projected design values are based on speciation profiles developed using 2002-2004 STN 

data. Appendix H-7 contains a sample Excel spreadsheet showing the calculations utilized 

to compute the 2009 DVF (displayed in Table V-2).

There are three FRM monitors in the Pittsburgh nonattainment area that are co-located 

with a speciated sampler: Florence, Greensburg, and Lawrenceville. However, since there 

are eleven FRM monitors within the Pittsburgh-Beaver Valley Area, the Department was 

able to determine that the three speciated monitors in the nonattainment area were 

representative of all FRM monitor locations in order to complete the SMAT analysis. 

RRFs were only calculated for the sulfates, nitrates, organic carbon, elemental carbon and 

crustal component of PM2.5. Referencing the PM2.5 FRM formula in section 3 above, the 

only components of PM2.5 that were not included in the RRF calculation were ammonium 

and water. Base and future case ammonium was calculated based on the DON value and 

the following formula presented in 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: 

NH4 = 0.29 * NO3 + DON * SO4.

The particle bound water was then calculated using the particle bound water formula 

estimated from the Aerosol Inorganic Model. Due to the hygroscopic nature of ammonium 

sulfate and ammonium nitrate, retained sulfate, nitrate and ammonium will all contain 

water. Therefore, the final polynomial equation (seen below and referenced (EPA, 2006 

(2))) contains sulfates, nitrates and ammonium within its calculation. The equation utilized 

was that for low acidity.

PBW = [202049.0 – 391494.6 * S – 390912.1 * N + 442.4 * (S^1.5) – 155.3 * (N^1.5)

- 293406.8 * (A^1.5) + 189277.5 * (S^2) + 377992.6 * N * S + 188636.8 * (N^2)

– 447.1 * (S^2.5) – 507.2 * (S^1.5) * N – 12.8 * (S^3) + 146.2 * (N^1.5) * S 

+ 217.2 * (N^2.5) + 30.0 * (N^1.5) * (S^1.5) – 18.6 * (N^3) + 216267.0 * (A^1.5) * S 

+ 215419.9 * (A^1.5) * N – 621.8 * (A^1.5) * (S^1.5) + 239.1 * (A^1.5) * (N^1.5) 

+ 35413.1 * (A^3)] * (SO4 + NO3+ NH4)

where

S = SO4 / (SO4 + NO3 + NH4)

N = NO3 / (SO4 + NO3 + NH4)

A = NH4 / (SO4 + NO3 + NH4)

Table V-1 displays the calculated quarterly RRFs for the design monitor of the PittsburghBeaver Valley Area, North Braddock. Based on the results of the RRF calculations, all 
48

PM2.5 constituents either remain the same or undergo a downward trend, except for the 

crustal portion.

Table V-1: Annual PM2.5 Quarterly RRF Values 

Quarter Sulfates Nitrates OC EC Crustal

1

st 0.9485 0.9806 0.9564 0.8426 1.1254

2

nd 0.7098 0.9081 1.0036 0.8456 1.2194

3

rd 0.6593 0.9179 0.9867 0.8405 1.2318

4

th 0.8942 0.9626 0.9966 0.8496 1.1628

Table V-2 presents the results of the annual SMAT results for all of the monitors in the 

Pittsburgh-Beaver Valley Area. The SMAT results demonstrate that the projected average 

annual arithmetic mean PM2.5 concentration calculated at each FRM monitor attains the 

annual PM2.5 NAAQS. Specifically, all DVF calculations are less than 15.0 μg/m3. Table 

V-2 presents the results of the annual SMAT results for a suite of regional modeling runs 

conducted by OTC, with each modeling run representing “On the Books, On the Way” 

(OTB/OTW) control measures. All runs demonstrate compliance with the annual 

NAAQS.

Table V-2: Annual SMAT Results for the Pittsburgh-Beaver Valley Area 2009 OnThe-Books-On-The-Way Control Measures

AIRS ID

Site 

Name County State

2000-2004 DVB 2009

Q1 Q2 Q3 Q4 DVF

420030008 Lawrenceville Allegheny PA 13.75 15.71 19.53 13.52 13.3

420030067 South Fayette Allegheny PA 10.89 13.27 17.34 11.20 11.3

420030093 N. Park Allegheny PA 11.90 14.74 18.00 11.07 11.8

420030095 Coraopolis Allegheny PA 12.41 15.63 17.83 11.74 12.2

420031008 Harrison Allegheny PA 14.25 16.60 19.51 13.02 13.5

420031301 N. Braddock Allegheny PA 15.07 16.64 20.49 14.81 14.3

420070014 Beaver Falls Beaver PA 14.50 14.93 20.32 13.82 13.6

421250005 Charleroi Washington PA 12.59 16.60 20.32 12.03 13.0

421250200 Washington Washington PA 12.42 15.12 19.90 12.08 12.7

421255001 Florence Washington PA 10.90 14.54 17.82 10.84 11.6

421290008 Greensburg Westmoreland PA 13.53 15.46 20.04 12.50 13.0

Source: 2000-2004 DVB quarterly concentrations calculated from data in Appendix A-2. 
49

6. 24-Hour SMAT Results

As with obtaining the annual SMAT Results, a difficulty presented in estimating the future 

design values was missing STN data for 2000 and 2001 at all of the Pittsburgh monitors. 

This limitation restricted the calculation of SANDWICH data to the period 2002–2004. 

Therefore, the 2009 projected design values are based on speciation profiles developed 

using 2002-2004 STN data. Appendix H-7 contains a sample Excel spreadsheet showing 

the calculations utilized to compute the 2009 DVF (displayed in Table V-4).

The RRF calculations were very similar to those that were computed in the annual SMAT 

analysis, except that all modeled RRFs were compared with each monitoring year’s 24-

hour 98th percentile design value. A quarterly analysis was completed consistent with the 

procedure outlined in 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 

(EPA-454/B-07-002, April 2007). 

The procedure that was completed was as follows. The top 25% of the days of the 

speciation and the modeling data were computed on a quarterly basis. The speciation data 

was compared with the quarterly PM2.5 FRM data to compute a speciated composition of 

the FRM data. Then after the RRFs were calculated (the RRF values for North Braddock, 

are shown below in Table V-3), these RRF values were applied to the speciated 

composition data to compute a 2009 speciated composition data. Once this was 

completed, a future year design value was reconstructed.

Table V-3: 24-hour PM2.5 Quarterly RRF Values 

Quarter Sulfates Nitrates OC EC Crustal

1

st 0.9755 0.9843 0.9408 0.8291 1.0992

2

nd 0.6295 1.0926 0.9893 0.8471 1.2694

3

rd 0.6182 0.9962 0.9902 0.8429 1.2801

4

th 0.9090 0.9839 0.9965 0.8503 1.1666

Table V-4 displays the 24-hour PM2.5 SMAT results for all of the monitors within the 

Pittsburgh-Beaver Valley Area. The SMAT results demonstrate that the projected 24-hour 

98th percentile PM2.5 concentration calculated at the FRM monitor attains the 24-hour 

PM2.5 NAAQS. Specifically, all DVF calculations are less than 65 μg/m3. Table V-4

presents the results of the 24-hour SMAT results for a suite of regional modeling runs 

conducted by OTC each representing OTB/OTW control measures. All runs demonstrate 

compliance with the 24-hour PM2.5 NAAQS.
50

Table V-4: 24-hour SMAT Results for the Pittsburgh-Beaver Valley Area 2009 OnThe-Books-On-The-Way Control Measures

AIRS ID

Site 

Name County State

24-Hour 98th Percentile DVB 2009

2000 2001 2002 2003 2004 DVF

420030008 Lawrenceville Allegheny PA 34.1 41.7 41.4 35.9 38.3 31.5

420030067 South Fayette Allegheny PA 32.0 37.0 47.6 42.1 42.2 31.3

420030093 N. Park Allegheny PA 33.9 37.9 52.5 56.6 47.2 38.1

420030095 Coraopolis Allegheny PA 31.1 38.4 46.2 38.6 46.6 33.1

420031008 Harrison Allegheny PA 41.6 48.1 46.2 41.9 45.4 35.0

420031301 N. Braddock Allegheny PA 39.7 51.7 41.9 50.4 38.3 33.6

420070014 Beaver Falls Beaver PA 43.6 49.3 37.7 33.8 43.0 31.9

421250005 Charleroi Washington PA 36.0 44.4 45.4 35.6 35.4 30.7

421250200 Washington Washington PA 33.3 38.9 37.2 33.4 34.0 28.8

421255001 Florence Washington PA 30.5 37.6 36.7 33.9 36.0 26.4

421290008 Greensburg Westmoreland PA 37.2 44.1 40.0 34.8 39.0 30.6

Source: 24-Hour 98th percentile DVB concentrations calculated from data in Appendix A-1. 

F. Unmonitored Area Analysis

Following 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 (EPA-454/B-07-

002, April 2007), an unmonitored area analysis “...is intended to ensure that a control 

strategy leads to reductions in ozone or PM2.5 at other locations which could have baseline 

(and future) design values exceeding the NAAQS were a monitor deployed.”

Projected annual PM2.5 concentrations surrounding the Pittsburgh-Beaver Valley Area

indicate most areas in the Commonwealth, including the Pennsylvania nonattainment areas 

immediately surrounding the Pittsburgh-Beaver Valley Area, are projected to attain the 

standard by 2009. This indicates there should be no areas where concentrations could 

reasonably be expected to exceed the annual PM2.5 NAAQS within the nonattainment area.

The fact that the Liberty-Clairton PM2.5 nonattainment area is a subsection of the 

Pittsburgh-Beaver Valley PM2.5 nonattainment area was also evaluated. The five (5) 

municipalities that make up the Liberty-Clairton PM2.5 nonattainment area were originally 

designated as nonattainment for PM10. At the time, the five (5) municipalities were tied 

together due to the extent at which the local source was believed to impact (due to local 

topographical and meteorological issues). In the time since the original PM10
51

nonattainment designation, the ACHD has monitored PM2.5 in municipalities surrounding 

the Liberty-Clairton PM2.5 nonattainment area. The monitoring data has confirmed the 

boundaries of the original PM10 nonattainment area, showing that the impacts of the local 

source within the region did not extend further than the five (5) municipality region.

The Air Quality Modeling Group (EPA Research Triangle Park) has developed the MATS, 

described on p. 39, above. MATS is a PC-based software tool that can perform the 

modeled attainment tests for PM2.5 and ozone (O3), and perform the uniform rate of 

progress analysis for regional haze (visibility). When this analysis was conducted, MATS 

was still in development and therefore was not utilized within this analysis. 

G. Local Area Analysis

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) suggests that it may be 

necessary to evaluate the impact of local primary PM sources for contributions to both the 

24-hour and annual NAAQS. Evaluation of local PM sources and their effects on monitor 

concentrations could be evaluated using a near-scale model such as AERMOD or 

CALPUFF.

Since the end of 2008, there are a total of nine (9) FRM monitors within the PittsburghBeaver Valley Area; five (5) FRM monitors run by the Department and four (4) FRM 

monitors run by the ACHD. In addition, there are three (3) speciation monitors and at least 

four (4) continuous PM2.5 monitors located within the Pittsburgh-Beaver Valley Area.

Pennsylvania has noted local source interference at Allegheny County’s North Braddock 

monitor (PA DEP, September 2004). North Braddock has the highest annual PM2.5 design 

value (15.5 μg/m3) and the highest 24-hour design value (40 μg/m3) in the PittsburghBeaver Valley Area in 2008. The 24-hour design value is below the (1997) 24-hour

standard indicating compliance with the NAAQS even with significant local effects. 

A review of the Commonwealth’s and Allegheny County’s 2002 emissions from the NEI

database indicates ten (10) large sources with greater than 50 tons per year (TPY) of direct 

PM2.5 emissions within 50 kilometers of the North Braddock PM2.5 monitor. These sources 

are listed in Table V-5. Each source’s PM2.5 emissions, distance from the North Braddock

monitor, direction from the North Braddock monitor, county and emission to distance ratio 

(Q/d) are included in the table.
52

Table V-5: Summary of Large PM2.5 Sources near the North Braddock Monitor

Source Emissions

(TPY)

Distance

(km) Direction County Q/d

US Steel – Edgar Thompson 472.0 1.2 S Allegheny 380.5

US Steel – Irvin 63.5 8.4 SE Allegheny 7.6

US Steel – Clairton Coke 394.0 11.1 SSE Allegheny 35.6

Glenshaw Glass Co. 58.8 15.2 NW Allegheny 3.9

Reliant – Cheswick 591.0 16.0 NE Allegheny 37.0

Reliant – Elrama 556.0 17.5 SSE Washington 31.8

Shenango Inc. 70.2 21.1 WNW Allegheny 3.3

Allegheny Energy – Mitchell 181.0 22.6 SE Washington 8.0

Alleg. Ludlum – Brackenridge 271.0 25.5 NE Allegheny 10.6

AK Steel – Butler Works 58.8 47.9 NNW Butler 1.2

The ratio of emissions to distance (Q/d) is often used as a screening tool to determine if a 

source could cause a significant model concentration. If a source’s Q/d ratio is larger than 

twenty (20) it usually warrants an analysis using a dispersion model. Table V-5 indicates 

four (4) sources exceed this Q/d ratio and probably warrant an analysis with a dispersion 

model to gauge their effects on the North Braddock monitor. A quick survey of local wind 

patterns utilizing meteorological data collected from 1998 to 2000 at the North Braddock 

monitor indicates the flow around the North Braddock area is influenced by the 

Monongahela River valley the monitor sits in. Therefore, as shown in Figure 10 below, 

the North Braddock area generally experiences a strong west, northwest flow or southeast 

flow. Based on the results from the wind rose analysis, three of the identified sources (US 

Steel – Edgar Thompson, US Steel – Clairton Coke, and Reliant - Elrama) lie upwind of 

the North Braddock monitor, while the other source (Reliant - Cheswick) lies in less 

favorable wind directions to transport direct PM2.5 emissions to the North Braddock

monitor.
53

Figure 10. Wind Rose: North Braddock Monitoring Location (1998-2000)

As noted earlier, the Department has observed enhancement of PM2.5 concentrations at the 

North Braddock monitor by local sources. Using emissions to distance ratios (Q/d) and 

local predominant wind directions; four (4) sources were identified for possible analysis 

with a dispersion model to gauge the effect of local direct PM2.5 emissions on the North 

Braddock monitor. A local area analysis using a dispersion model, however, was not 

conducted since the modeled concentrations for the North Braddock monitor currently 

would attain the PM2.5 NAAQS. This does not preclude the Department from conducting a 

dispersion modeling analysis as part of a local area analysis in the future for the EPA’s 

revised 24-hour PM2.5 standard.

The 2002 inventory was based on emissions reported to the Department by facilities and 

did not include condensables for many facilities. If a local area analysis is needed in the 

future to address the 2006 PM2.5 NAAQS, the analysis would likely be based on inventory 

data from a more recent baseline year. At that point, the Department could evaluate 

whether the baseline inventory includes PM2.5 condensables, as appropriate.

H. Weight of Evidence and Other Documentation Supporting Attainment

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 
54

analyses, collectively referred to as “weight of evidence” (WOE), help bolster the 

assertions that an area will achieve attainment in the allotted time.

Table V-6 outlines the types of supplemental information that EPA suggests will satisfy a 

weight of evidence demonstration. Generally, the analyses become more complicated as 

the projected modeled values increase. The projected 2009 design value for the annual 

standard in the Pittsburgh-Beaver Valley Area, 14.3 μg/m3, is below the lower bounds of 

the range of 14.5 μg/m3to 15.5 μg/m3 for which 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) requires a formal weight of evidence demonstration.

According to 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), areas, such as the Pittsburgh-Beaver Valley Area, that have a projected design 

value lower than 14.5 μg/m3 are recommended to provide basic supplemental analyses to 

support the result of the modeling demonstration. The basic supplemental analyses can 

include additional modeling, analysis of trends in the monitoring data or emissions and/or 

observational models and diagnostic analyses. The Department’s supporting evidence 

includes a brief summary of the modeling demonstration, recent trends in the PittsburghBeaver Valley Area’s monitoring data and a brief analysis of some of the largest SO2

sources within the nonattainment area.

Table V-6: Summary of PM2.5 Weight of Evidence Guidelines (EPA Guidance)

Results of Modeled Attainment Test Supplemental Analyses

Annual PM2.5 24-Hour PM2.5

Future Design Value 

< 14.5 μg/m3, all sites

Future Design Value 

< 62 μg/m3, all sites

Basic supplemental analyses should 

be completed to confirm the 

outcome of the modeled attainment 

test

Future Design Value 

14.5 – 15.5 μg/m3, all 

sites

Future Design Value 

62 – 67 μg/m3, all 

sites

A weight of evidence demonstration 

should be conducted to determine if 

aggregate supplemental analyses 

support the modeled attainment test

Future Design Value 

≥ 15.5 μg/m3, all sites

Future Design Value 

≥ 68 μg/m3, all sites

More qualitative results are less 

likely to support conclusion 

differing from the outcome of the 

modeled attainment test

2009 Projected Modeling Concentration: The Department’s attainment demonstration 

relies on results from the OTB/OTW CMAQ runs completed by the Virginia Department 

of Environmental Quality. Emissions for the base case (2002) and projected (2009) time 
55

frames were developed by MARAMA with input from all states that are part of the OTR 

plus the District of Columbia. Base-case and projected emissions within the PittsburghBeaver Valley Area appear to be reasonable; therefore, the projected design value for 2009 

should reflect what will actually be monitored.

Recent analyses of projected CMAQ ozone design values suggest the model may actually 

underestimate the impact of emission reductions on actual concentrations. This modeled 

underestimation of changes in ozone concentrations may be due to the model’s inability to 

adequately reproduce changes in ozone concentrations due to large emission reductions. If 

CMAQ has the same shortfall with fine particulate concentrations, then it may also 

overestimate the projected 2009 PM2.5 design values for the Pittsburgh-Beaver Valley 

Area. Since the calculated design value is already well below 15.0 μg/m3, any 

overestimation of the projected 2009 annual PM2.5 design value provides a further cushion 

bolstering the argument that the Pittsburgh-Beaver Valley Area will reach attainment.

In addition, the 2002 inventory was based on emissions reported to the Department by 

facilities. In 2002, many facilities did not include condensables in their estimates of direct 

PM2.5. The projected 2009 PM2.5 emissions for EGUs include condensable PM. For 

EGUs, emissions of condensable PM were calculated based on 2009 operating parameters 

predicted by IPM and emission factors derived from AP-42 defaults. Because the 2002 

inventory was based on emissions reported to the Department by facilities and did not 

include condensables for many facilities, the emissions inventory shows an apparent 

increase in PM2.5 emissions from stationary sources from 2002 to 2009.

If the 2002 emissions inventory were corrected to account for the unreported condensable

emissions, the modeled 2009 PM2.5 concentrations would be lower, i.e., the PittsburghBeaver Valley Area would be predicted to attain the standard by a larger margin. If the 

2002 emissions inventory were corrected to account for the unreported condensable

emissions, 2002 would have higher total PM2.5 emissions in the inventory. Within the 

modeling, a concentration was calculated for 2002 and 2009 (based on their respective 

inventories). Then, in order to calculate the anticipated 2009 monitored concentration, 

DEP utilized the speciated pollutants (such as sulfates, nitrates, elemental carbon, organic 

carbon, etc.) constructed from the 2002 and 2009 modeling runs. Then a ratio (known as a 

relative reduction factor (RRF)) was applied, using the results of the 2002 and 2009 

modeling. The RRF is calculated by dividing the 2009 modeled results by the 2002 

modeled results. Therefore, if the 2002 emissions inventory had higher total PM2.5

emissions, the RRF calculated would have been lower (with a larger number being the 

denominator of the RRF calculation). With a lower RRF, the calculated speciated 

component attributable to the direct PM2.5 emissions would have been lower, lowering the 

overall 2009 PM2.5 predicted concentration.

PM2.5 and Emission Trends: Long-term trends were analyzed for all PM2.5 monitors in 

Pennsylvania, using PM2.5 modeling protocols. No statistically significant trends in the 

2001-08 design values were noted for the Pittsburgh-Beaver Valley Area monitors. This 

finding was not unexpected, since it appears that many monitors within the region are 
56

heavily influenced by the mobile-source sector, which has recently had significant controls 

imposed on it.

Figure 11 shows the values for the monitor (North Braddock) displaying the highest annual 

and 24-hour PM2.5 concentration in the Pittsburgh-Beaver Valley Area from 1999 through 

2008. Over the last two years, annual PM2.5 averages appear to have declined slightly. In 

fact, all PM2.5 monitors, excluding North Braddock, in the Pittsburgh-Beaver Valley Area

are now in compliance with the annual PM2.5 standard. This may be due to a combination 

of weather conditions and emission decreases in the mobile source sector. While this is 

probably not a statistically significant trend, it may be indicative of lower future PM2.5

design values more in line with the annual PM2.5 standard.
57

Figure 11: Pittsburgh-Beaver Valley Area PM2.5 Trends 

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58

Controls on the largest SO2 sources in the Pittsburgh-Beaver Valley Area, including 

Allegheny Energy – Hatfield’s Ferry, Reliant – Keystone, and Reliant – Cheswick

facilities, are scheduled to be operational in 2009. The projected SO2 emission rates for 

these three (3) sources should provide a substantial reduction in sulfate levels within the 

Pittsburgh-Beaver Valley Area. As seen in Figure 5 (in this Section V), sulfate is a major 

contributor to the Pittsburgh-Beaver Valley Area’s PM2.5 nonattainment problem. This 

reduction in PM2.5 precursors coupled with somewhat lower recent annual PM2.5 

concentrations bolsters the Commonwealth’s assertion that the Pittsburgh-Beaver Valley 

Area will soon be in compliance with the PM2.5 NAAQS.

I. Conclusions

The Pittsburgh-Beaver Valley Area’s projected 2009 annual PM2.5 concentration was 

estimated using the OTC’s modeling platform. A review of the base case (2002) run

indicated the CMAQ model did a reasonable job reproducing actual concentrations. Based 

on this analysis, it is reasonable to assume the model can estimate the projected PM2.5

concentrations within the Pittsburgh-Beaver Valley Area for 2009. The Department 

understands that the EPA anticipates using 2009 data to determine whether the PittsburghBeaver Valley Area attains the PM2.5 standard by its April 2010 attainment date.

Projected PM2.5 concentrations from CMAQ indicate the Pittsburgh-Beaver Valley Area

will attain the annual standard by 2009. Additional evidence supporting this conclusion 

includes lower concentrations at all of the PM2.5 monitors within the Pittsburgh-Beaver 

Valley Area the last couple of years, significant SO2 controls installed on some of the 

largest sources within the nonattainment area and possible model under-predictions of the 

air quality benefits of emission reductions.
59

VI. CONTINGENCY MEASURES FOR THE ATTAINMENT DEMONSTRATION

A. Contingency Measure Requirement

Pursuant to 40 CFR 51.1012, the attainment plan for the Pittsburgh-Beaver Valley Area

must include a contingency plan that contains measures that qualify as contingency 

measures for the attainment demonstration. This section fulfills the contingency 

measures requirement for the attainment demonstration. The contingency plan must 

provide for one year of reductions needed for attainment. 

By 2009, emissions of SO2 and NOx in the Pittsburgh-Beaver Valley Area are projected 

to decrease by 347,796 tons and 86,586 tons, respectively. Based on modeling of the 

projected 2009 emissions, the Pittsburgh-Beaver Valley Area is predicted to have a 2009 

design value of 14.3 ug/m3. This is lower than the 15 ug/m3required for attainment of 

the PM2.5 standard. Calculations were made to estimate the portion of the emission 

reduction that is necessary to reach the attainment concentration of 15 ug/m3and the 

portion of the emission reduction that reduces the design value below 15 ug/m3and is, 

therefore, excess.

Table VI-1 contains information about the changes in design value and emissions 

expected by 2009 in the Pittsburgh-Beaver Valley Area. Table VI-1 displays the 2002

actual and 2009 modeled design values and the 2002 actual and 2009 projected emissions 

of PM2.5, SO2 and NOx. 

Table VI-1: Changes in Design Value and Emissions Expected by 2009

Pittsburgh-Beaver Valley Area

Design 

Value 

(ug/m3)

PM2.5

(tons/year)

SO2

(tons/year)

NOx 

(tons/year)

2002 16.8 14904 476871 198483

2009 (Modeled/Projected) 14.3 27969 129074 111897

Predicted Change from 2002-2009 2.5 -13066 347796 86586

As shown in Table VI-2, for each pollutant, the change in pollutant emissions was 

divided by the predicted change in design value to yield the design value reduction rate. 

Next, the change in design value necessary to attain the standard (16.8 ug/m3– 15 ug/m3

= 1.8 ug/m3) was multiplied by the design value reduction rate to estimate the target 

emissions reduction. This represents the portion of emissions reduction necessary to 

attain the standard. The rest of the emissions reduction is beyond what is necessary for 

attainment and is, therefore, considered to be “excess” reduction.
60

Table VI-2: Calculation of Required and Excess Emissions Reductions

Pittsburgh-Beaver Valley Area

Design 

Value 

(ug/m3)

PM2.5

(tons/year)

SO2

(tons/year)

NOx 

(tons/year)

Predicted Change from 2002-2009 2.5 -13066 347796 86586

Design Value Reduction Rate 

(tons/ug/m3)

N/A 139119 34634

Target Reductions for Attainment 1.8 N/A 250413 62342

Calculated Excess Reductions 0.7 N/A 97383 24244

The contingency requirement is calculated by dividing the target emissions reduction by 

seven which is the number of years between 2002 and 2009. Table VI-3 shows the 

calculation of the contingency requirement reduction and demonstrates that the 

calculated excess reduction exceeds the amount of reduction necessary for the 

contingency plan.

Table VI-3: Calculation of Required Contingency Plan Reductions

Pittsburgh-Beaver Valley Area PM2.5

(tons/year)

SO2

(tons/year)

NOx 

(tons/year)

Target Reductions for Attainment N/A 250413 62342

Calculated Excess Reductions N/A 97383 24244

Contingency Requirement N/A 35773 8906

Excess Reductions Satisfy 

Contingency Requirement N/A Yes Yes

B. Identified Contingency Measures

In addition to the calculated excess reductions shown in Tables VI-2 and VI-3 above, 

the Department has identified additional control measures. 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 
61

milestone or to attain. The EPA states that any implemented measures (that are not 

needed for the rate-of-progress requirements or for the attainment requirements) would 

need to be “backfilled”, meaning replaced with another measure, only to the extent 

they are used to meet a milestone.8

The reductions from the designated contingency measures are surplus vis-à-vis the 

attainment demonstration contained in this SIP. As a result, the Department will not be 

required to replace any contingency measures that it chooses to implement in advance of 

the contingency plan requirement. 

The following describes specific control measures that are anticipated to be in place in 

order to bring the area back into attainment should a violation occur.

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. The Department 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. The 

Department may also utilize enhanced enforcement to obtain additional emission 

reductions.

Significant additional reductions in NOx, direct PM2.5 and, to a limited extent, SO2

emissions will occur in emissions from highway and nonroad mobile sources after 2009. 

NOx emissions from mobile sources are more than one-third of the emissions in 2009.

In addition, the following regulations are in development and are anticipated to be adopted

in the relatively near future:

NOx controls for cement kilns 

NOx controls for glass furnaces 

PM controls for outdoor wood furnaces 

Regulations to reduce VOC emissions are also 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.

Once the Department’s Bureau of Air Quality has obtained an approved request to initiate 

a rulemaking, the rulemaking may proceed as follows:

 

8 EPA, "Guidance on the Post-1996 Rate-of-Progress Plan and the Attainment Demonstration," 

Corrected Version as of February 18, 1994, p. 50.
62

Within 2 months: Review by Air Quality Technical Advisory Committee 

(AQTAC), Citizens Advisory Council and other advisory committees,

9

as 

appropriate.

Within 5 months: Environmental Quality Board (EQB) meeting/action. 

Within 7 months: Publication in the Pennsylvania Bulletin for comment as 

proposed rulemaking. 

Within 9 months: Public hearing takes place and comment period on proposed rule 

closes. 

Within 10 months: House and Senate Standing Committees and Independent 

Regulatory Review Commission (IRRC) comment on proposed rule. 

Within 12 months: AQTAC, Citizens Advisory Council and other committees, as 

appropriate, review responses to comments and draft final rulemaking. 

Within 15 months: EQB meeting/action.

Within 16 months: IRRC action on final rulemaking.

Within 17 months: Attorney General review/action. 

Within 18 months: Publication in the Pennsylvania Bulletin as final rulemaking and 

submission to the EPA as a SIP revision. The regulation would become effective 

upon publication in the Pennsylvania Bulletin. 

 

9 Other committees could include the Small Business Compliance Advisory Committee and Agriculture 

Advisory Committee. 
63

REFERENCES

SECTION I

Pope III, C. Arden, M. Ezzati and D. Dockery. “Fine-Particulate Air Pollution and Life 

Expectancy in the United States.” New England Journal of Medicine. 360: 376-386 

January 22, 2009. 

EPA, 2007. Clean Air Fine Particle Implementation Rule. Final Rule. 72 FR 20586 

(April 25, 2007).

SECTION III

EPA, 2005. Emissions Inventory Guidance for Implementation of Ozone and Particulate 

Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations. 

EPA-454/R-05-001. August, 2005. Updated November, 2005

Final Technical Support Document, Development of Emission Projections for 2009, 2012, 

and 2018 for NonEGU Point, Area, and Nonroad Sources in the MANE-VU Region. 

Prepared by MACTEC for MARAMA, February 28, 2007.

Final Regulatory Analysis: Control of Emissions from Marine Diesel Engines, EPA, 

November 1999. 

SECTION V

The Nature of the Fine Particle and Regional Haze Air Quality Problems in the MANE-VU 

Region: A Conceptual Description. Prepared by the Northeast States for Coordinated AirUse Management (NESCAUM), November 2006.

Summary of Pennsylvania’s PM2.5 Nonattainment Analysis, Prepared by the Pennsylvania 

Department of Environmental Protection, October 2007.

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

Quality Goals for Ozone, PM2.5, and Regional Haze. EPA, EPA-454/B-07-002, April 

2007.

Final Air-Quality Modeling Protocol for the Annual PM2.5 NAAQS: Pittsburgh-Beaver 

Valley Annual PM2.5 Nonattainment Area, prepared by the Pennsylvania Department of 

Environmental Protection, October 2007.

A Modeling Protocol for the OTC SIP Quality Modeling System For Assessment of the 

Ozone National Ambient Air Quality Standard in the Ozone Transport Region, The 

Modeling Committee of the Ozone Transport Commission, March 2006.
64

CMAQ Model Performance and Assessment for Base Year 2002: PM2.5 Mass and 

Speciation, Prepared by the New York State Department of Environmental Conservation, 

December 2007.

Clegg, S.L., P. Brimblecombe, and A. S. Wexler, (1998), “Aerosol Inorganics Model; A

Thermodynamic Model of the System H+ - NH4+ - SO42- - NO3- - H2O at Tropospheric

Temperatures.”, J. Phys. Chem., 102A, 2137-2154.

(http://www.aim.env.uea.ac.uk/aim/project.htm).

EPA, 2004. Procedures for Estimating Future PM2.5 Values for the CAIR Final Rule by 

Application of the (Revised) Speciated Modeled Attainment Test (SMAT). July 26, 2004. 

Available on EPA’S CAIR PDF web page (www.epa.gov/CAIR/pdfs/Revised-SMAT.pdf).

EPA, 2006. Definition of SANDWICHed STN Data. November 1, 2006. Available on 

EPA’s Air Explorer web page (www.epa.gov/mxplorer/sandwich_description.doc).

EPA, 2006 (2). SANDWICH Material Balance Approach for PM 2.5 Data Analysis 

(Presented at the 2006 National Air Monitoring Conference). November 6-9, 2006. 

Available on EPA’s AMTIC web page 

(www.epa.gov/ttn/amtic/files/ambient/2006conference/frank.pdf).

SECTION VI

U. S. EPA, "State Implementation Plans; General Preamble for the Implementation of 

Title I of the Clean Air Act Amendments of 1990", Proposed Rule, 57 Federal 

Register 13,498 (April 16, 1992).

EPA, "Guidance on the Post-1996 Rate-of-Progress Plan and the Attainment

Demonstration," Corrected Version as of February 18, 1994, p. 50.

OTC 2007. Identification and Evaluation of Candidate Control Measures: Final 

Technical Support Document. Prepared by MACTEC Federal Programs, Inc., Herndon, 

Virginia for the Ozone Transport Commission. February 28, 2007.
65

ACRONYMS AND ABBREVIATIONS

ACHD Allegheny County Health Department

AIM Architectural and Industrial Maintenance Coatings

AQTAC Air Quality Technical Advisory Committee

BACT Best Available Control Technology

CAA Clean Air Act

CAIR Clean Air Interstate Rule

CA LEV California Low Emission Vehicle (program)

CF Control Factor

CFR Code of Federal Regulations

CMAQ Community Multi-scale Air-Quality Model

CMV Commercial Marine Vessel

DON Degree of Neutralization

DVB Baseline Design Value

DVF Future Design Value

EC Elemental Carbon

EDMS Emissions and Dispersion Modeling System

EGAS Economic Growth Analysis System

EGU Electric Generating Unit

EIA Energy Information Administration

EPA The United States Environmental Protection Agency

EQB Environmental Quality Board

FAA Federal Aviation Administration

FIP Federal Implementation Plan

FIRE Factor Information Retrieval 

FMVCP Federal Motor Vehicle Control Program

FR Federal Register

FRM Federal Reference Method

HAP Hazardous Air Pollutant

ICI Industrial, Commercial, Institutional

I/M Inspection and Maintenance

IPM Integrated Planning Model

IRRC Independent Regulatory Review Commission

LDGV Light Duty Gasoline Vehicles

LDGT Light Duty Gasoline Trucks

MACT Maximum Achievable Control Technology

MANE-VU Mid-Atlantic/Northeast Visibility Union

MARAMA Mid-Atlantic Regional Air Management Association

MATS Modeled Attainment Test Software

MM5 Mesoscale Model Version 5

MPO Metropolitan Planning Organization

MY Model Year

NAAQS National Ambient Air Quality Standard

NAICS North American Industry Classification System

NBP NOx Budget Program

NESCAUM Northeast States for Coordinated Air-Use Management
66

NH3 Ammonia

NH4

+ Ammonium

NLEV National Low Emission Vehicle (program)

NMIM National Mobile Inventory Model

NOx Oxides of Nitrogen

NO2 Nitrogen Dioxide

NO3

- Nitrates

NSR New Source Review

OC Organic Carbon

OM Organic Mass

OTAQ Office of Transportation and Air Quality

OTB On the Books

OTC Ozone Transport Commission

OTW On-the-Way

OTR Ozone Transport Region

PBW Particle Bound Water

PennDOT Pennsylvania Department of Transportation

PIT Pittsburgh International Airport

PM Particulate Matter

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

PM10 Particulate Matter less than 10 microns in diameter

ppm parts per million

PSD Prevention of Significant Deterioration

PSU/NCAR Pennsylvania State University National Center for Atmospheric Research

RACM Reasonably Available Control Measure

RACT Reasonably Available Control Technology

RE Rule Effectiveness

RFP Reasonable Further Progress

RP Rule Penetration

RPO Regional Planning Organization 

RRF Relative Response Factor

RVP Reid Vapor Pressure

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

Balance Approach

SCC Source Classification Code

SCR Selective Catalytic Reduction

SIP State Implementation Plan

SMAT Speciated Modeled Attainment Test

SMOKE Sparse Matrix Operator Kernel Emissions 

SO2 Sulfur Dioxide

SO4

-

Sulfates

STN Speciation Trends Network

TCM Transportation Control Measures

TEOM Tampered Element Oscillating Microbalance Monitor

TSD Technical Support Document 

μg/m3 Microgram per cubic meter
67

μm Micrometer 

VISTAS Visibility Improvement State and Tribal Association of the Southeast 

VMT Vehicle Miles Traveled 

VOC Volatile Organic Compound 

WOE Weight of Evidence 

ZEV Zero Emissions Vehicle 
4500445684 10107 

COMMONWEALTH OF PENNSYLVANIA 

STO-52-1 REV. 12~BB 

IHVO!CENo. 

PUBUCATIONS:AUTHORIZATION AND INVOICE 154613 . PUBLICATIONS AUTHORIZATION (To be completed by agency): 

TO: (NAME AND,ADDRESS OF NEWSPAPER) 

Pittsburgh Post 

34 Boulevard of 

Pittsburgh, PA 

Gazette 

the Allies 

15222 

• FEDERAL to. NO,ISOC. SEC. NO. 

94-0692700 F!l..OM, 'NAME ANq,~DDR'W bF AGENCY) 'AG',,",-TeIJ'PHOI"l'."" 9 4 9 5 Ivette l'l. House : 111-/~/-

400 Market Street'···················· 

Bureau of Air Quality 

Harrisburg, PA 17105 

HEREWITH IS ENCL.OSED COPY FOR PUBUCATION OF ADVERT1SE;MENT FOi't PROPOSALS TO 

o EMPLOY 0 PURCHASE 0 CONTRACT 

puaUSH ADVERTISEMENT (NO. OF TIMES) .IMAX'MUM NO. OF UNES 

DATES OF INSERTION 

CI~ber41Z.009, edition #8449655 

TYPE OF AD 

o SELL o CI...ASSIFlED ~ LEGAL NOTICE 

DATE 

August 26, 2009 I ORDER NO. 

S'G~tt2~A:rlL((1p7Lv-. 

You, as vendor, are aulhorized to publish this advertisement in your newspaper, subject to the terms of this order, as 

follows: Advertisement to be published in regular advertising columns, no position specified; caption of two lines and signature 

to be in capitals and subject matter and title of officer. to be set solid in type regularly' used by_y'our newsm![1er for Rublic (!!1gal) 

notice advertising; charge to be made at the rate charged to and paid by commercial advertisers for matter similarly set and 

occupying similar space; advertisement to be run in the editions specified above. Vendor agrees that. in the performance of any 

contract awarded to it hereunder, said vendor will not discriminate against any employe or other persons on account of race, color, 

sex, religious creed, ancestry, age or national origin and that the Commonwealth, upon receipt of satisfactory evidence of such 

discrimination, shall have the rightto cancel said contract. Return this copy at once if you will not acceptthis advertisement underthe terms 

set forth. 

Proof of advertising in the form of a tearsheet must be included on Parts 1 ,2 & 3. Return original and two copies (signed 

by the editor or publisher) to Agency listed above. Part 1 must be notarized. Part 4 is yours. 

Commonwealth to be billed only for actual number of printed lines published. 

ACCOUNT FUND 

CODE ::;'11 f/ 

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1stAd 

2nd Ad 

DEPT APP YEAR 

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3rd Ad B~~~r FY~~~'~~ Nonattainment Area; Public Hearing particulate matter 

(PM) includes both' solid GRAND TOTAL .... 

AMOUNT 

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_____________________ and liquid particles sus-~-------~.--------.L--------~---'--­ pended in the air. Fine r- particle-'pollution'de-

~~~i~~~fi~ri~~iat~a~~~_ SHEET HERE 

equal,to 2,5 micfome-

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Commonwealth of Pennsylvania ~~~~ih:b~~eed ~radn~~~d 

County of Allegheny pose a senous human ~ health threat Health ~ J Bo t Before me the subscriber a Notary Pl stud,es have shown a County personally came __ -=..: • ....:=0= __________ _ , , slgmflcant aSSOCiatIOn ' who being duly sworn, doth depose and say tt between exposure to "t~ ________________________ _ fine particles and prema- I 

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that the advertisement, of which tearsheet is 1~~V!?'j,':,s:,ro~~'e"";'~i ES published in the regular advertlsing'doibmns of said newspaper, 

in the editions of said newspaper, in all ref ~~~~b~~~~e~g5~CX~~~~1;and invoiced above; and that the Commonwealth is not charged 

therefor at a rate higher than is charged any primary (health-baSed),1 advertiser for a similar amount of matter occupying similar space 

d . "1 ···d and secondary (wei an set In a Simi ar manner .. In sal newSpaper-fare-based)'PM2.5 stan 

dard of 15.0 microgram~ 

per cubic meter <ilg/m3), . 

Sworn anct subscribed before me this ~~~~~ ~?,,~~en~1t~eaaV~ 

day of ....... :., /::..:- D ".-." -.. j PM2.5 concentrations. ,- . - The EPA also estab-

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21 countles·as PM2.S ' 
PA Bulletin, Doc. No. 09-1665 Page I of2 

NOTICES 

Proposed Revision to the State Implementation Plan for the Pittsburgh-Beaver 

Valley, Pennsylvania Fine Particulate Nonattainment Area; Public Hearing 

[39 Pa.B. 5278] 

[Saturday, September 5, 2009] 

Particulate matter (PM) includes both solid and liquid particles suspended in the air. Fine particle 

pollution describes PM that is less than or equal to 2.5 micrometers in diameter (PM2.5)· PM2.

5 

concentrations above the Federal health-based standard pose a serious human health threat. Health 

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

from heart or lung disease. In 1997, the United States Environmental Protection Agency (EPA) 

established an annual primary (health-based) and secondary (welfare-based) PM2.5 standard of 15.0 

micrograms per cubic meter (f-lg/m\ based on the 3-year average of annual mean PM2.

5 

concentrations. The EPA also established a primary and secondary 24-hour standard of 65 f-lg/m3 

determined by the 3-year average of the 98th percentile of 24-hour concentrations. Implementation 

of the standard was delayed due to legal challenges. In this Commonwealth, the EPA designated 

eight areas comprised of all or parts of 18 connties as PM2.

5 nonattainment areas for the annual 

standard. For each nonattainment area, the Commonwealth is required to develop a State 

Implementation Plan (SIP) revision that demonstrates how the area will attain the standard by the 

prescribed attainment date, April 5, 2010. 

The Department of Environmental Protection (Department) is seeking public comment on the SIP 

revision for the Pittsburgh-Beaver Valley PMz.5 nonattainment area (Pittsburgh-Beaver Valley 

Area). The proposed SIP revision contains information on PM2.5 trends and emissions to 

demonstrate that the Pittsburgh-Beaver Valley Area meets all requirements necessary for an 

approvable SIP revision. The proposed SIP revision demonstrates how the area will attain the 

PM2.

5 stan4ard by April 5, 20 I 0, by presenting evidence from air quality modeling, emission 

trends, regional pollutant transport impacts and emission reductions through state and Federal 

control measures. In addition, the proposed revision to the SIP contains the base year 2002 

emissions inventory, mobile source emission budgets for purposes of transportation conformity and 

a contingency plan to bring the area back into attainment should future violations of the standard 

occur. After consideration of comments received, the SIP revision will be finalized and submitted 

to the EPA for approval. 

The proposed PM2.

5 SIP revision for the Pittsburgh-Beaver Valley Area is available on the 

Department's web site at www.depweb.state.pa.us (choose "Air Topics") or through the contact 

persons listed. Notice of the proposed SIP revision will also be published in newspapers of general 

circulation in the affected area. 

The Department will hold a public hearing to receive comments on the proposal on October 6, 

2009, at I p.m. at the Department's Southwest Regional Office, 400 Waterfront Drive, Pittsburgh, 

http://www.pabulletin.comlsecure/datalvoI39/39-36/1665.html 10/2312009 
PA Bulletin, Doc. No. 09-1665 Page 2 of2 

P A. Persons wishing to present testimony at the hearing should contact Yvette House, P.O. Box 

8468, Harrisburg, PA 17105, (717) 787-9495 oryhouse@state.pa.ustoreserveatime.Personswho 

do not reserve a time will be able to testify as time allows. Witnesses should keep testimony to 10 

minutes and should provide two written copies of their statement at the hearing. 

Persons with a disability who wish to attend the hearing and require an auxiliary aid, service or 

other accommodation to participate in the proceeding should contact Yvette House at (717) 787-

9495 or yhouse@state.pa.us. TOO users may contact the Pennsylvania AT&T Relay Service at 

(800) 654-5984 to discuss how the Department can best accommodate their needs. 

The Department must receive comments no later than October 9,2009. Written comments should 

be sent to the attention of Arleen Shulman, Division of Air Resource Management, Bureau of Air 

Quality, P. O. Box 8468, Harrisburg, PA 17105-8468, ashulman@state.pa.us. Use "Pittsburgh 

PMz.5 SIP" in the subject line. 

JOHN HANGER, 

Secretary 

IPa.B. Doc. No. 09-1665. Filed for public inspection September 4, 2009, 9:00 a.m.] 

No part of the information on this site may be reproduced for profit or sold for profit. 

This material has been drawn directly from the official Pennsylvania Bulletin full text database. 

Due to the limitations of HTML or differences in display capabilities of different browsers, this 

version may differ slightly from the official printed version. 

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http://www.pabulletin.comlsecure/data/voI39/39-36/1665.html 10/23/2009 
1

Commonwealth of Pennsylvania

Comment and Response Document for the 

Pittsburgh-Beaver Valley Fine Particulate Attainment Demonstration 

October 2009

On September 5, 2009, the Pennsylvania Department of Environmental Protection (DEP 

or Department) published a notice of public hearing and commenced a 30-day written 

comment period on the proposed attainment demonstration and base year inventory for 

the Pittsburgh-Beaver Valley fine particulate (PM2.5) nonattainment area (Beaver, Butler, 

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

and Lawrence counties) 39 Pa.B. 5278. The public hearing was held at the DEP’s 

Southwest Regional Office, 400 Waterfront Drive, Pittsburgh, PA on Tuesday, October 6, 

at 1 p.m. The comment period closed on October 9, 2009.

This document summarizes the testimony received during the public hearing and the 

written comments received prior to the close of the public comment period. The list of 

commentators is set forth below: 

COMMENTATORS:

1. natashasoroka@aol.com (no information other than email was supplied)

2. Rachel Filippini

Executive Director

Group Against Smog and Pollution, Inc.

Wightman School Community Building

5604 Solway St., #204

Pittsburgh, PA 15217

(oral testimony)

3. Joint letter from the following parties:

Joe Osborne, Esq.

Legal Director

Group Against Smog and Pollution, Inc.

5604 Solway St., #204

Pittsburgh, PA 15217

Charles McPhedran, Esq.

Senior Attorney

Citizens for Pennsylvania’s Future

1518 Walnut Street, Suite 1100

Philadelphia, PA 19102-3406
2

Tom Hoffman

Western Pennsylvania Director

Clean Water Action

100 5th Avenue #1108

Pittsburgh, PA 15222

4. James Thompson, Air Director

Allegheny County Health Department

301 39th Street

Pittsburgh, PA 15201-1891

COMMENTS AND RESPONSES

COMMENTS: 

1. COMMENT: While the EPA’s Clean Air Fine Particle Implementation Rule 

gives states and localities discretion to determine if control measures for PM precursors 

such as VOCs should be considered, the rule also states that “[i]f information

brought forward by commenters or the State in the SIP development process shows that 

the presumption in this rule for . . . VOC . . . is not technically justified for a particular

nonattainment area, the State must conduct a technical demonstration to reverse the

presumption.”

The rule lists examples of “the types of analyses that would be appropriate to use in

developing such a demonstration.” Included among these examples are “[s]pecialized

monitoring and laboratory studies [that] assess the relative concentrations of organic

compounds.” In 2009, such a study analyzed air toxics in Allegheny County and found 

that thirteen of thirty six monitored organic air toxics exceeded the national 75th 

percentile at one or more monitoring sites. (The study is referenced as Allen Robinson 

et. al., Air Toxics in Allegheny County: Sources, Airborne Concentrations, and Human 

Exposure, Final Technical Report for Allegheny County Health Dept. at 3 (Mar. 2009), 

available at: 

www.achd.net/air/pubs/pdf/CMU%20Air%20Toxics%20FINAL%20REPORT%20REVIS

ED%20MAR%2009.pdf)

All thirteen of the elevated compounds belong to chemical classes that have been 

recognized for their potential to contribute to PM2.5 concentrations. Most significant, 

seven of these thirteen chemicals are aromatic compounds, which “are considered to be 

the most significant anthropogenic SOA [secondary organic aerosol] precursors and 

have been estimated to be responsible for 50 to 70 percent of total SOA in some 

airsheds.” Based on this data, we believe PADEP must perform a technical 

demonstration to determine if VOCs significantly contribute to PM2.5 concentrations in 

the nonattainment area. (3)
3

RESPONSE: The Department appreciates the commentator’s information regarding the 

contribution of volatile organic compounds (VOCs) to PM2.5 concentrations in the 

Pittsburgh-Beaver Valley area.

As the commentator indicates, the U.S. Environmental Protection Agency’s (EPA’s)

PM2.5 Implementation Rule establishes general presumptive policies for assessing which 

PM2.5 precursors should be evaluated for possible controls. The EPA requires states to 

evaluate measures for VOCs only if the state or EPA makes a technical demonstration to 

show VOCs significantly contribute to PM2.5 in that nonattainment area. EPA discusses 

the reasons for this position in the preamble to the final implementation regulation (Clean 

Air Fine Particle Implementation Rule, 72 Fed. Reg. 20586 (Apr. 25, 2007)). While the 

fact that some VOCs can form secondary organic aerosol (SOA) is not disputed, the 

formation of SOA, and therefore the contribution of VOCs to fine particle concentrations, 

is complex and also highly variable, even on short time scales. EPA recognizes that 

further research and standardized and approved technical tools are needed to better 

characterize emissions inventories for specific VOCs and determine their contribution to 

fine particle formation. 

The Department considered the data in the report on air toxics in Allegheny County 

referenced by the commentator. First, the Department assessed whether emissions of the 

13 air toxics found in the study at elevated concentrations comprise a large percentage of 

VOC emissions in Allegheny County. In 2004, Allegheny County point sources emitted 

a total of 314 tons of the 13 air toxics based on air toxics emissions data published in the 

air toxics report referenced by the commentator. According to the Allegheny County 

Health Department 2004 Point Source Emission Report (available at 

http://www.achd.net/air/pubs/pdf/aqemissionrpt2004.pdf ), Allegheny County point sources 

emitted a total of 2587 tons of VOC in 2004. Based on this information, in 2004, 

emissions of the 13 elevated air toxics account for approximately 12% of Allegheny 

County’s VOC emissions. DEP does not conclude that this represents adequate support 

to technically justify the Department or EPA developing a demonstration that VOCs 

should be addressed in the region’s PM2.5 attainment plan.

DEP also assessed other available data that EPA suggests would be appropriate to 

consider in developing a demonstration to reverse the presumption that VOCs do not 

need to be included in the PM2.5 attainment plan for the Pittsburgh-Beaver Valley area. 

VOC emissions are projected to decrease by 18,036 tons per year (22%) from 80,898 tons 

per year in 2002 to 62,862 tons per year in 2009, primarily due to federal and state 

control measures being adopted for purposes of reducing ground-level ozone. VOCs are 

a known contributor to ozone. Despite the substantial reduction in VOCs, the modeling 

conducted shows a minimal reduction in PM2.5 concentrations. Based on the average of 

all Pittsburgh-Beaver Valley monitors, the calculated quarterly average relative reduction 

factors ranged from 0.96 – 1.03 for the organic carbon fraction of PM2.5 as a result of the 

22% reduction in VOC. This may indicate that VOC reductions are not as vital as 

reductions of other precursors for attainment of the PM2.5 standard in the PittsburghBeaver Valley area. 
4

Overall, the Department concludes that there is too much uncertainty regarding the role 

of VOCs in the formation of fine particulate to reverse the presumption at this time. In 

the future, the Department intends to continue to work with other states and EPA to 

develop tools to assess the role of VOCs in the formation of fine particulate. 

2. COMMENT: DEP must carry out an analysis to determine if VOC controls 

would provide for a more timely, certain, or cost effective PM2.5 control strategy. (1,2)

RESPONSE: The Department disagrees that the rule states that DEP must carry out an 

analysis to determine if VOC controls are necessary under the conditions the 

commentator describes. Section 51.1002(c)(3) states that a state is not required to 

address VOC as a precursor and evaluate sources of VOC emissions for control measures 

unless the state or EPA provides an appropriate technical demonstration.

Furthermore, the requirements for Reasonably Available Control Measure (RACM) 

analysis under Section 51.1010(b) are to consider measures that would advance the 

attainment date by one year. Since the attainment date is in less than one year, there are 

no additional measures that could advance the attainment date in that fashion. The 

criteria for improving certainty and cost-effectiveness do not appear in either section. 

3. COMMENT: If VOCs are a significant contributor, more timely and costeffective PM2.5 reduction methods may be available in the form of VOC controls. (3)

RESPONSE: As indicated in the response to Comment #1, the Department has 

concluded that too much uncertainty remains regarding the role of VOC in particulate 

formation to develop a demonstration that VOC significantly contributes to PM2.5 

concentrations in the Pittsburgh-Beaver Valley area.

That said, the Pittsburgh-Beaver Valley is also a nonattainment area for ground-level 

ozone, for which VOCs are clearly a precursor and well understood. The Commonwealth 

has adopted a series of controls for VOCs to reduce ozone and is developing additional 

measures for adhesives, primers, sealants and solvents as well as coatings for many 

commercial/industrial processes. As tools improve to measure emissions and account for 

the formation of fine particles, the Commonwealth will be able to include the benefits of 

VOC controls in future State Implementation Plan (SIP) revisions to meet the more 

protective standards established in 2006. 

4. COMMENT: Modeling assumptions for projecting 2009 emissions may be 

overestimated. (1,2)

RESPONSE: The assumptions used when inventories were projected and air quality 

modeling done were the best available at the time. 
5

5. COMMENT: Second, modeling assumptions used to project 2009 emissions 

may overestimate real-world air quality improvements. For instance, the automobile 

fleet turnover rates used to determine the age and emissions levels of US automobiles is 

based on annual vehicle sales in 2000. Given the current economic challenges, 2008 and 

2009 auto sales are lower by roughly half than those included in the CMAQ model. (1,2)

RESPONSE: Fleet turnover rates can have significant impacts on the benefits from 

federal and state vehicle control strategies and ultimately on the forecasted emission 

totals. Since this item significantly impacts calculations, Pennsylvania does not use 

MOBILE6.2 defaults in the preparation of the inventory. Instead, county-specific vehicle 

registration data is obtained on a triennial basis and used within the emission calculation 

process. Future SIP and transportation conformity submissions will utilize more recent 

planning assumptions as they are obtained and prepared for emission analyses. 

Variations in vehicle sales volumes and among the various vehicle types may occur 

between the update cycles. Since the complex regional modeling was performed using a 

2005 inventory and not all states update fleet age in the same fashion, the most current 

uniform data available at the time were used. DEP agrees that this may overestimate fleet 

turnover and air quality improvements. However, both the soaring gasoline and diesel 

prices in portions of these years as well as the economic situation also curtailed vehicle 

miles traveled, which would have the opposite effect. 

6. COMMENT: Another example [of modeling assumptions]: projected 2009 

emissions include estimated reductions in SO2 and NOx from the Clean Air Interstate 

Rule or CAIR. However, in the time since these estimations were made, the D.C. Circuit 

declared the rule “fatally flawed” and remanded it to EPA. Industry uncertainty, first 

about whether the rule would continue to exist, and now about the final form of EPA’s 

CAIR replacement has caused electricity generators to cancel or delay SO2 and NOx 

controls originally intended under CAIR. (1,2)

RESPONSE: EPA has advised states that because CAIR remains in effect during the 

remand, assumptions made about its effects in PM2.5 SIPs for very near term attainment 

years such as 2009 remain valid. The Department does not believe that any controls 

installed in anticipation of CAIR have been shut down because of “industry uncertainty.”

7. COMMENT: In 2006, prompted by evidence that the 1997 standard was 

insufficient to protect public health, EPA issued an updated, more protective standard. 

While SIP revisions to comply for the new standard will not be due for several years, we 

believe that given the health threat that additional years of exceeding the 2006 standard 

entail, DEP should make every effort to bring our region into compliance with the 2006 

standard in the current SIP revision. (1,2)

RESPONSE: While the current SIP revision is designed to address the 1997 NAAQS,

the Department is working in many ways to achieve even greater PM2.5 reductions. 

Pennsylvania is supporting collaborative efforts on a regional basis to ensure EPA 

considers the 2006 standard in a rule to replace CAIR, is urging EPA to develop national 
6

standards for controls of SO2 and NOx from industrial, commercial and institutional 

boilers, is developing a rule to regulate outdoor wood burning furnaces, is finalizing its 

rules to limit NOx from cement kilns and glass furnaces. In addition, the Department 

anticipates developing a regulation to reduce sulfur content in residential, commercial 

and industrial fuel oils. Additional measures will be examined once preliminary 

modeling information for the 2006 standard (based on 2007 inventories and assumptions) 

is available on the amount of emission reduction necessary to attain that standard. A SIP 

for the 2006 standard will be submitted in a timely fashion.

 

8. COMMENT: The Proposed SIP Revision shows sharp increases in direct 

emissions of PM 2.5 between 2002 and 2009 (see Table E-1, p. iii). These increases 

appear to come from stationary sources (compare Table III-1, p. 14 and Table III-2, p. 

17). These increases also show up as “negative reductions,” especially striking when 

compared with the actual reductions in sulfur dioxide (SO2) and nitrogen oxides (NOx) 

over the same time period (Table IV-1, p. 23). From conversations with DEP, we 

understand that this reflects a difference in the methodology for counting condensable 

PM between the 2002 actual inventory, in which most sources do not report 

condensables, and the 2009 projected inventory, which is based on a model

that does include condensables. We suggest that DEP clarify this aspect of its approach 

to the emission inventory in the Proposed SIP Revision. (3)

RESPONSE: DEP agrees that the SIP revision could benefit from clarification 

regarding the emission inventory methodology and explanatory language has been added. 

The 2002 inventory was based on emissions reported to the Department by facilities. In 

2002, many facilities did not include condensable PM in their estimates of direct PM 

emissions. For most source categories, the 2009 inventory was developed by projecting 

the 2002 inventory forward to 2009 using growth factors. For electric generating units

(EGUs), the Integrated Planning Model (IPM) was used to predict 2009 operating 

parameters and emissions. The projected 2009 PM2.5 emissions for EGUs include 

condensable PM emissions which were calculated based on operating parameters 

predicted by IPM and emission factors derived from AP-42 defaults. Because the 2002 

inventory did not include condensables for many facilities, the emissions inventory shows 

an apparent increase in PM2.5 emissions from stationary sources from 2002 to 2009.

If the 2002 emissions inventory were corrected to account for the unreported condensable

emissions, the modeled 2009 PM2.5 concentrations would be lower, i.e., the PittsburghBeaver Valley area would be predicted to attain the standard by a larger margin.

If the 2002 emissions inventory were corrected to account for the unreported condensable

emissions, 2002 would essentially have higher total PM2.5 emissions in the inventory.

Within the modeling, a concentration was calculated for 2002 and 2009 (based on their 

respective inventories). Then, in order to calculate the anticipated 2009 monitored 

concentration, DEP utilized the speciated pollutants (such as sulfates, nitrates, elemental 

carbon, organic carbon, etc.) constructed from the 2002 and 2009 modeling runs. Then a 

ratio (known as a relative reduction factor (RRF)) was applied, using the results of the 

2002 and 2009 modeling. The RRF is calculated by dividing the 2009 modeled results by 

the 2002 modeled results. Therefore, if the 2002 emissions inventory had higher total 
7

PM2.5 emissions, the RRF calculated would have been lower (with a larger number being 

the denominator of the RRF calculation). With a lower RRF, the calculated speciated 

component attributable to the direct PM2.5 emissions would have been lower, lowering the 

overall 2009 PM2.5 predicted concentration.

9. COMMENT: On page i of this SIP the full name of the "Pittsburgh -Beaver 

Valley non-attainment area" is given the short name of the "Pittsburgh area." The 

remaining 67 pages then use the term "Pittsburgh area." Over many years the City of 

Pittsburgh has experienced a difficult time in removing its antiquated image as a "smoky 

city." This use of the name Pittsburgh to refer to the eight-county area reinforces this past 

image to those who are not aware of the large region. We request the term "Pittsburgh 

area" be replaced with the "Pittsburgh-Beaver area" to more accurately represent the 

larger community this non-attainment area this represents. (4)

RESPONSE: The SIP has been changed to reflect the full name of the nonattainment 

area (Pittsburgh-Beaver Valley).