Responses to Significant Comments on the State and 

Tribal Designation Recommendations for the 2012 

Annual PM2.5 National Ambient Air Quality Standard 

(NAAQS) 

 

Docket Number the EPA-HQ-OAR-2012-0918 

U.S. Environmental Protection Agency 

December 2014
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 2 of 68

Table of Contents 

List of Acronyms ................................................................................................................ 3 

1.0 Introduction .............................................................................................................. 5 

2.0 Background .............................................................................................................. 5

3.0 Responses to Significant Comments on the State and Tribal Designation 

Recommendations for the 2012 annual PM2.5 National Ambient Air Quality Standard 

(NAAQS) ............................................................................................................................ 6 

3.1 General Issues ...................................................................................................... 6 

3.1.1. Data Considerations ...................................................................................... 6 

3.1.2. Requests to Extend the Public Comment Period .......................................... 9 

3.1.3. Other General Comments ............................................................................. 9 

3.2 Area-Specific Issues ........................................................................................... 10 

3.2.1. EPA Region III ........................................................................................... 10 

3.2.2. EPA Region IV ........................................................................................... 22 

3.2.3. EPA Region V............................................................................................. 27 

3.2.4. EPA Region VI ........................................................................................... 54 

3.2.5. EPA Region IX ........................................................................................... 57 

3.2.6. EPA Region X............................................................................................. 58 

3.2.7. Multi-Region Areas .................................................................................... 63 

3.2.7.1. Louisville, KY-IN......................................................................................... 63 

3.2.7.2. Cincinnati-Hamilton, OH-KY ..................................................................... 65 

3.2.7.3. St. Louis, MO-IL ......................................................................................... 67 
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List of Acronyms 

APCD Air Pollution Control District 

AQS Air Quality System 

CAA Clean Air Act 

CBSA Core Based Statistical Areas 

CFR Code of Federal Regulations 

CSA Combined Statistical Area 

CSPAR Cross-state Air Pollution Rule 

DFW Dallas-Fort Worth, Texas 

EER Exceptional Events Rule 

EGU Electric Generating Unit 

EPA Environmental Protection Agency 

FR Federal Register 

GA EPD Georgia Environmental Protection Division 

HGB Houston-Galveston-Brazoria, Texas 

HYSPLIT Hybrid Single Particle Lagrangian Integrated Trajectory Model 

IEPA Illinois Environmental Protection Agency 

I/M (Vehicle) Inspection and Maintenance 

μg/m3 Micrograms per cubic meter 

MPO Metropolitan Planning Organization 

MSA Metropolitan Statistical Area 

NAA Nonattainment Area 

NAAQS National Ambient Air Quality Standard 

NEI National Emissions Inventory 

NFR Notice of Final Rulemaking 

NLLJ Nocturnal Low Level Jet 

NOAA National Oceanic and Atmospheric Administration 

NOx Oxides of Nitrogen 

NSPS New Source Performance Standards 

NSR New Source Review 

OAQPS EPA Office of Air Quality Planning and Standards 

OMB Office of Management and Budget 

PM2.5 Fine Particulate Matter 

PSD Prevention of Significant Deterioration 

QAPP Quality Assurance Project Plan 

QA/QC Quality Assurance/Quality Control 

RICE Reciprocating Internal Combustion Engine 

SC DEHC South Carolina Department of Health and Environmental Control 

SIP State Implementation Plan 

SLAMS State and Local Air Monitoring Stations 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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TCEQ Texas Commission on Environmental Quality 

TPY Tons per Year 

TSD Technical Support Document 

TVA Tennessee Valley Authority 

VMT Vehicle Miles Traveled 

VOC Volatile Organic Compounds 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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1.0 Introduction 

This document, together with the preamble to the final rule, and the Technical 

Support Documents (TSDs) for the designations, presents the EPA’s responses to the 

significant comments we received on our proposed designations. The responses presented 

in this document are intended to augment the responses to comments that appear in the 

preamble to the final rule and the TSDs or to address comments not discussed in those 

documents. Commenters can find TSDs in the electronic docket for this action 

(www.regulations.gov, docket number the EPA-HQ-OAR-2012-0918) and at the EPA’s 

PM Designations Web Page 

(http://www.epa.gov/pmdesignations/2012standards/index.htm). 

2.0 Background 

On December 14, 2012, the EPA promulgated a revised primary annual PM2.5 NAAQS 

(78 FR 3086, January 15, 2013). In that action, the EPA revised the primary annual PM2.5

standard, strengthening it from 15.0 micrograms per cubic meter (μg/m3

) to 12.0 μg/m3; 

retained the existing 24-hour PM2.5 standard at 35 μg/m3; retained the existing 24-hour 

PM10 (coarse particle) standard at 150 μg/m3; and retained the current suite of secondary 

PM standards. The EPA revised the primary annual PM2.5 standard based on an integrated 

assessment of an extensive body of new scientific evidence, which substantially 

strengthens our body of knowledge regarding PM2.5-related health effects. The revised 

primary annual PM2.5 standard will provide increased protection for children, older adults, 

persons with pre-existing heart and lung disease, and other at-risk populations against an 

array of PM2.5-related adverse health effects, including premature mortality, increased 

hospital admissions and emergency department visits, and development and exacerbation 

of chronic respiratory disease. 

History shows us that better health and cleaner air go hand-in-hand with economic 

growth. Working closely with the states and tribes, the EPA is implementing the standard 

using a commonsense approach that improves air quality and minimizes the burden on 

state, local, and tribal governments. As part of this routine process, the EPA is working 

with the states and tribes to identify areas in the country that meet the standard and those 

that need to take steps to reduce PM2.5 air pollution. Within 1 year of promulgating a new 

or revised air quality standard, the Clean Air Act requires the Governor of each state to 

submit to the EPA a list of all areas in the state, with a designation recommendation for 

each area. As a first step in implementing the 2012 annual PM2.5 standard, Governors 

(and tribal leaders, if they chose) were to submit their designation recommendations, 

including appropriate area boundaries, by December 13, 2013. 

On August 19, 2014, the EPA sent letters (the “120-day letters”) to state and tribal 

representatives responding to their recommendations and identifying those areas 

anticipated to meet the 2012 annual PM2.5 standards and those that do not. States, tribes, 

and the public had the opportunity to comment on the EPA’s proposed decisions before 

the Agency issued final area designations, and to provide new information and analyses 

to the EPA, if appropriate. Following are summaries of significant comments received on 

the 2012 annual PM2.5 designation recommendations and the EPA’s responses to those 

comments. 
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3.0 Responses to Significant Comments on the State and Tribal 

Designation Recommendations for the 2012 annual PM2.5 National 

Ambient Air Quality Standard (NAAQS) 

The following sections address the comments received by the EPA on the state and tribal 

PM2.5 designation recommendations for the 2012 annual PM2.5 NAAQS. Comment 

summaries and responses are presented below. 

3.1 General Issues 

3.1.1. Data Considerations 

Comment: Several states, including Georgia, Indiana, Ohio, and Pennsylvania, believe 

that data for one or more of the areas violating the 2012 annual PM2.5 NAAQS based on 

2011-2013 air quality data may show attainment based on 2012-2014 air quality data. 

Because the EPA is promulgating initial area designations in December 2014, which is 

very close to the end of the 2014 data year, these states asked the EPA to consider 2012-

2014 data in their designation decisions, or to defer the designations process until after 

2014 data are complete and state and federal regulators have an opportunity to consider 

areas that may have come into attainment. One commenter noted that deferring 

designations to allow consideration of 2014 data would constitute a minimal delay in the 

designations process and would eliminate needlessly subjecting these areas to further 

nonattainment requirements and burdening the states and the federal government with 

developing plans, redesignation requests and maintenance plans for areas that allegedly 

do not necessitate these activities. 

EPA Response: The EPA is basing initial area designation decisions for most areas for 

the 2012 annual PM2.5 NAAQS on air quality monitoring data for the 2011-2013 time 

period because these data represent the most recent certified data available in August 

2014 at the time the EPA notified states of any intended revisions to the states’ and 

tribes’ designation recommendations. However, because the EPA is making final 

designation decisions in December 2014, we believe it is appropriate to allow interested 

states and tribes to early certify their 2014 data ahead of the May 1, 2015 deadline 

specified in 40 CFR part 58.15(a)(2). States and tribes wishing to certify and submit their 

2014 data for consideration in final designation decisions, should submit the certified 

2014 data for all monitors in the desired area by February 27, 2015. The EPA established 

this deadline to ensure that we would have adequate time to evaluate the new technical 

information and complete the interactive process between the EPA and the states, as 

contemplated by the Act, as we determine the final area designations. 

Comment: State commenters, including Alabama and Texas, note that through the 

regulatory provisions in 40 CFR Sections 50.13 and 50.18, the EPA establishes the 

requirements for operating state ambient air quality monitoring networks. The EPA then 

verifies through technical systems audits that air agencies are following these 

requirements. The EPA also uses these monitoring data to determine when the primary 
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and secondary PM2.5 NAAQS are met. The commenters believe that unless these criteria 

are not met, areas with monitor values that meet the specified criteria should be 

designated attainment. The commenters believe a designation of “attainment” is further 

supported by the definitions in the Clean Air Act. CAA sections 107(d)(1)(A)(i), (ii) and 

(iii) (42 U.S.C. 7407) which provide definitions for “attainment,” “nonattainment,” and 

“unclassifiable,” but do not include a definition for “unclassifiable/attainment.” 

Commenters note that the EPA uses the category “unclassifiable/attainment” “without 

clear definition, criteria, or statutory basis” to designate those areas that are monitoring 

attainment and for areas that do not have monitors but for which the EPA has reason to 

believe are likely attainment and are not contributing to nearby violations. The state 

commenters recommend that areas monitoring attainment should be designated as 

attainment in December 2014. 

EPA Response: In the April 16, 2013, guidance Initial Area Designations for the 2012 

Revised Primary Annual Fine Particle National Ambient Air Quality Standard, the EPA 

said that states could submit recommendations identifying areas as “attainment,” but that 

the EPA expected to continue to use the “unclassifiable/attainment” category for 

designations for the 2012 annual PM2.5 NAAQS. (See footnote 2 at page 2). As we have 

done with past initial area designation efforts for other NAAQS, for these designations, 

the EPA is using a designation category of "unclassifiable/attainment" for areas that are 

monitoring attainment and for areas that do not have monitors but for which the EPA has 

reason to believe are likely attainment and are not contributing to nearby violations. The 

EPA is using “unclassifiable” for those areas where the EPA was not able to determine 

based on available information whether the area is meeting or not meeting the NAAQS, 

or where the EPA was not able to determine that the area contributes to a nearby 

violation. 

Comment: One commenter expresses concern about the EPA’s proposal to designate 

numerous areas as “unclassifiable” based on data quality and completeness issues. The 

commenter notes that because the EPA has historically treated unclassifiable areas as 

though they meet the standard and are not subject to the stronger protections required for 

nonattainment areas, the EPA is effectively denying millions of people the protection 

they deserve under the standard. The commenter adds that under previous designations 

efforts, the EPA has taken the position that once it has designated an area as 

unclassifiable, the Agency had no obligation to redesignate the area, even if adequate 

data showing nonattainment become available. The commenter adds that following this 

course of action encourages states to “follow sloppy or deficient data collection and 

analyses” because it results in the “reward” of avoiding a nonattainment designation. 

The commenter recommends that the EPA pursue the following: 

 For historically nonattaining areas (i.e., Chicago, St. Louis, Atlanta, and 

Knoxville) with invalid or incomplete 2011-2013 data, use the most recent prior 

years for which adequate, quality-controlled data show violation of the 2012 

annual PM2.5 NAAQS unless the EPA provides evidence showing that air quality 

has improved and no longer violates the standard (treating such areas as anything 

other than nonattainment is arbitrary and unlawful). 
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 Alternatively, extend the time for promulgating final designations by the additional 

year provided under 42 U.S.C. §7407(d)(1)(B)(i) for the portions of the eight 

states/territories for which the EPA is proposing unclassifiable designations based 

on data quality/completeness issues (Puerto Rico; U.S. Virgin Islands; Atlanta, 

Glynn County and Dougherty County, Georgia; Tennessee (except Chattanooga); 

Illinois; St. Louis, Missouri; and areas of Indian Country, CA). Commenter notes 

that the EPA has proposed to provide such an additional year for designations in 

Georgia, and there is no reason to take a different approach as to the other areas 

with data adequacy and quality issues. 

 As was done with the recent 1-hour sulfur dioxide standard, develop a plan to 

designate areas with insufficient monitoring data based on modeling or additional 

monitoring. 

 The EPA must also put in place steps to work with the states and tribes to review 

the available data and to expeditiously update the laboratory systems to restore the 

quality controls needed for the data measurement. 

EPA Response: The EPA appreciates the commenter’s concerns and acknowledges that 

the extent of incomplete/invalid data associated with the initial area designations for the 

2012 annual PM2.5 NAAQS is unprecedented. The EPA also agrees with the commenter 

that it makes sense to extend the time for promulgating designations using the authority 

provided under section 107(d)(1)(B) of the CAA. As such, the EPA is deferring initial 

area designations for ten areas where currently available data, including air quality 

monitoring data, are insufficient to determine whether the areas are meeting or are not 

meeting the NAAQS. For these areas (i.e., Atlanta, GA; Albany, GA; Augusta, GA-SC; 

Brunswick, GA; Columbus, GA-AL; Savannah, GA; Valdosta, GA; Washington Co, GA; 

the entire state of Florida; and the entire state of Tennessee, excluding three counties in 

the Chattanooga area), the EPA believes that additional air quality monitoring data will 

result in complete and valid data sufficient to inform a designation determination. 

In this action, the EPA is finalizing a designation of unclassifiable for those remaining 

areas identified as “unclassifiable” in the 120-day letters (i.e. Puerto Rico; US Virgin 

Islands; and the entire state of Illinois, including two counties in Indiana as part of the 

Chicago area and four counties and one city in Missouri as part of the St. Louis area) 

because these areas have ambient air quality monitoring sites that lack complete data for 

the period 2011-2013. After reviewing the ambient air quality monitoring data for these 

areas for 2012, 2013 and 2014, the EPA believes that near-term data will continue to be 

insufficient to determine valid design values and, therefore, that deferring designations 

would not be helpful. Additionally, a review of data prior to 2013 indicates similar data 

quality and/or completeness issues such that the EPA lacks the confidence in historical 

data needed to support a designation based on recent prior years. The EPA is working 

closely with the appropriate air agencies to ensure that complete, quality-assured data are 

gathered moving forward and will continue to conduct technical systems audits of each 

ambient air monitoring organization every 3 years as required under 40 CFR part 50, 

Appendix A. The EPA will evaluate complete and valid data for “unclassifiable” areas 

when they become available. 

    
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3.1.2. Requests to Extend the Public Comment Period 

Comment: Two commenters requested that the EPA extend the deadline for the public 

comment period beyond September 29, 2014, to allow interested parties additional time 

to review docket materials and provide substantive comments. 

EPA Response: In its August 29 Federal Register notice (79 FR 51517) announcing the 

availability of the EPA’s responses to state and tribal designation recommendations for 

the 2012 annual PM2.5 NAAQS, the EPA invited public comment through September 29, 

2014. In the “120-day” letters, the EPA asked states and tribes to provide any additional 

comments by October 29, 2014. The EPA established these staggered deadlines to allow 

the states and tribes to address any public comments and to allow the EPA to review and 

respond to all significant public, state, and tribal comments in advance of promulgating 

the initial area designations in December 2014 according to our statutory designations 

deadlines. For these reasons we were unable to extend the comment period. 

3.1.3. Other General Comments 

Comment: One commenter noted that the regulatory burden associated with the EPA’s 

process of designating nonattainment areas will negatively affect areas by causing 

economic harm. 

EPA Response: Section 107(d)(1) of the CAA directs the EPA to designate an area 

“nonattainment” if it is violating the NAAQS or if it is contributing to a violation of the 

NAAQS in a nearby area. The first step in designating nonattainment areas is to identify 

air quality monitoring sites with 2011-2013 data that show a violation of the 2012 annual 

PM2.5 NAAQS. To determine whether a nearby area is contributing to a violation, the 

EPA recommended that states conduct a technical analysis based on a number of factors 

listed in the designation guidance for the 2012 annual PM2.5 NAAQS, including air 

quality, emissions and emissions-related data, meteorology, geography/topography, and 

jurisdictional boundaries. In evaluating whether to modify a state’s designation 

recommendation, the EPA also considered those factors as documented in the EPA’s 

technical support document for the identified nonattainment area. In determining whether 

an area should be designated nonattainment under section 107(d), the EPA did not 

consider economic impacts because they are not relevant for determining whether an area 

is violating the NAAQS or is contributing to a nearby violation. 

Control obligations in areas designated nonattainment for the 2012 annual PM2.5 NAAQS 

will be addressed through a separate implementation rulemaking. As the EPA considers 

the required components of implementation plans for the 2012 annual PM2.5 NAAQS, the 

Agency intends to provide states flexibility and opportunities to maximize efficiency to 

the extent such approaches are consistent with the CAA and will not jeopardize 

expeditious attainment of the public health and welfare goals of the CAA. In addition, the 

EPA is exploring ways that it can provide assistance to the states on this issue. Finally, to 

the extent the CAA does not mandate specific control measures, states may consider 

economic concerns in development of their state implementation plans to address air 

quality. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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3.2 Area-Specific Issues 

3.2.1. EPA Region III 

Comment: Pennsylvania Department of Environmental Protection (PADEP) and 

Allegheny County Health Department (ACHD) urged the EPA to reconsider its intended 

boundary from that of Allegheny County to the historical five borough Liberty-Clairton 

boundary that has served as the boundary for this area in the past PM2.5 designations, 

given that the only violating monitor is the same monitor the EPA relied upon for its past 

designations under the annual and 24-hr PM2.5 NAAQS designations. All other monitors 

located in the County are not only currently attaining the standard, but demonstrating a 

historical downward trend that provides confidence in continuing attainment of the 

standard. 

Commenters stated that it is inappropriate for the EPA to expand its nonattainment 

boundary for the Liberty-Clairton area to include the entirety of Allegheny County and 

that the historical boundary for Liberty-Clairton is appropriate given that the only 

violating monitor is located within the historical boundary. 

The commenters noted that the Liberty monitor is located in an area that has historically 

demonstrated a very significant localized industrial impact that requires separate planning 

approach that the EPA has recognized in past designation processes. However, 

commenters claimed that in the initial TSD for Allegheny County, the EPA ignored 

precedent and attempted to link sources in other parts of the County including the 

urbanized area of the City of Pittsburgh to a violating monitor that is subject to a unique 

mix of meteorology topography and localized emissions. The Commenters argued that 

the EPA’s justification for the entire County is confusing, because in several instances the 

EPA cited the “dominant” influence of local emissions on the Liberty monitor. 

EPA Response: Section 107(d)(1) requires the EPA to designate as nonattainment not 

only any area that violates the NAAQS, but also any area that contributes to ambient air 

quality in a nearby area violating the NAAQS. The EPA has therefore always based its 

nonattainment decisions upon a full comprehensive factor-based analysis, taking into 

consideration all aspects that drive violations of the standard both in areas violating the 

NAAQS and also in nearby areas contributing to areas violating the NAAQS. However, 

the EPA must also evaluate contribution from all nearby areas portion of the area of in 

the analysis. 

Our current Allegheny County boundary decision for the 2012 PM2.5 NAAQS is based on 

only a single violating monitor -- the Liberty monitor which also formed the basis for 

past Liberty-Clairton PM nonattainment areas. Though there is only one violating 

monitor in the larger Pittsburgh CBSA, all nearby emissions sources in the area must be a 

evaluated for potential contribution to the violating monitor. Based on the EPA’s five 

factor analysis and additional analysis performed in response to the commenters’ 
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December 17, 2014 

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analysis, sources within Allegheny County outside the local Liberty-Clairton area are 

contributing to the violating Liberty monitor. 

The EPA reviewed the commenters’ supplemental information and analysis, and agrees 

with the commenters, to some degree, with their technical analysis as it relates to 

conditions affecting the violating Liberty monitor, particularly in light of its proximity to 

an industrial source that contributes significantly to the violation, and in light of 

topographical and meteorological conditions present at the monitor site. These conditions 

and the EPA’s additional analysis of the commenters’ information provided and further 

explained in responses throughout this section and in the TSD. 

Although the EPA agrees to some extent with the commenters’ supplemental analysis 

with respect to the significant contributor to the violation, the commenters’ analysis 

focuses on a significant contribution and does not address or disprove potential 

contribution to the violation from nearby sources in the remainder of the county (e.g., 

mobile, area, and point emission sources). The commenter primarily notes that the 

localized Liberty-Clairton area is a “significant contributor” to the violating monitor; 

however, the statute is clear in providing for inclusion in nonattainment areas of areas 

that “contribute” to the violations. The EPA interprets the term “contributes” to mean 

contributes sufficiently to justify inclusion in the nonattainment area, and the EPA’s 

multifactor test with the various analytical tools is intended to assure an objective 

evaluation of the appropriate facts on a case by case basis in each area. The EPA has 

considered multiple factors of analysis, and has applied the same analysis to all counties 

considered in the area of analysis as outlined in the TSD. The EPA’s decision is not 

contingent on only one part of the analysis, but the analysis as a whole especially given 

that PM is a complex pollutant with contribution from multiple source categories as well 

as multiple pollutants. Hence, the EPA’s use of the weight of evidence approach 

evaluating the facts and circumstances in each area on a case by case basis, and was done 

consistently with decision principles to assure comparable treatment in all the 

designations. 

As demonstrated by the five factor analysis in the TSD for the Allegheny County area 

and supplemental analyses performed in light of the commenters’ additional information, 

the EPA has determined that though there is significant contribution from the local 

sources to the violating monitor, there is also contribution from sources within the 

remainder of Allegheny County impacting the violating monitor. 

The commenters’ focus on data from the violating Liberty monitor furthermore does not 

assess what is happening on all days versus high days for the annual PM2.5 NAAQS. To 

further assess this potential for broader contribution, the EPA conducted its own 

additional analysis of monitor concentrations and wind directions for all days in a period 

between 2011 and 2013. This analysis, further explained in the TSD, shows that under 

certain conditions on a large number days that there is some degree of contribution from 

sources in the surrounding Allegheny County area to the violating Liberty monitor. 
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Comment: PADEP and ACHD are concerned that inclusion of the entirety of Allegheny 

County in the nonattainment area would subject all sources therein to Reasonable Further 

Progress (RFP) requirements, increasing the baseline for RFP and resulting in a greater 

emission reduction required to meet RFP. Commenters assert that there are limited 

remaining emission controls available in the remainder of the County, and that ACHD 

has limited control over emissions from transportation sources in the county. 

The commenters state that designation of the entire county as nonattainment for the 2012 

PM2.5 NAAQS would result in three different nonattainment boundary areas in the same 

County (1997/2006 PM2.5, 2012 SO2, and 2012 PM2.5 NAAQS). The commenters allege 

this is not consistent with the EPA’s recent SIP improvement outreach efforts and would 

place a considerable burden on resources for the ACHD. It is also important to note that 

the significant stationary sources in other areas of the County besides the Liberty-Clairton 

area will be subject to any controls that are required to meet the 2012 SO2 NAAQS. 

EPA Response: The EPA notes its willingness and capability to work closely with state 

partners in their development of attainment plans. The EPA also acknowledges the 

commenters’ concern regarding attainment planning, however the statutory basis for area 

designations is not one of whether sources are controlled or controlled adequately at the 

time of designations. The issue is also not whether sources can or should be controlled for 

purposes of implementing the NAAQS. That question is something that is evaluated in 

the context of the attainment plan that the state will develop once an area is designated as 

nonattainment. Whether sources in an area are already adequately controlled for a prior 

PM2.5 NAAQS because of existing attainment plan SIP measures for that NAAQS is also 

not a singular deciding factor in determining designations for a new NAAQS because the 

emissions from sources (controlled or uncontrolled) may still be contributing to a 

violation of the more stringent 2012 PM2.5 NAAQS. With respect to the commenters’ 

contention regarding expanded RFP requirements as a result of a broader nonattainment 

boundary, each NAAQS must be evaluated on the basis of violations of that standard, 

current ambient air quality, and the contribution to the violation from within the 

established nonattainment boundaries., Designations determinations are therefore 

irrespective of RFP consequences which are statutorily addressed in separate, subsequent 

attainment planning. 

With respect to the selection of jurisdictional boundaries for the area, each NAAQS must 

be evaluated independently of the other. The EPA does consider the historical 

jurisdictional boundaries in our intended designations while we attempt to align 

boundaries and overlap jurisdictional control when determining boundaries for a new 

NAAQS. Boundaries however may vary for different NAAQS based on the source 

contribution and location of violations specific to each NAAQS. The EPA has given 

consideration to jurisdiction issues in the Allegheny County designation, but based on its 

analysis of the potential for sources in the area to contribute to the violating monitor, the 

EPA has determined the Allegheny County designation is appropriate though it may 

differ from the historical jurisdictional boundaries for this area. The EPA acknowledges 

and appreciates that PM2.5 planning for this area is under ACHD and PADEP’s 

jurisdiction, and that both agencies have a long history of cooperation for planning in the 

Allegheny County area. 
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Comment: PADEP and ACHD assert that the EPA dismissed the influence of industrial 

(stack) emissions from Washington County including two nearby power plants due to 

complex terrain, but ignored the same complex terrain in an attempt to link ground level, 

urban emissions from the City of Pittsburgh from a greater distance as a contributor to the 

Liberty monitor. Commenters further allege this is also despite the fact that the Liberty 

monitor only violates the standard when the prevailing wind is from the South or 

Southwest and not from the Northwest which is the direction of the City of Pittsburgh. 

Commenters also argue that there is a monitor located only 3.5 miles from the Liberty 

monitor in Clairton that consistently reads 3 to 4 μg/m3

 lower than Liberty (among the 

lowest readings in the County) which does not demonstrate urban influence on the area. 

Commenters argue that the EPA is inconsistent in its reasoning for Pittsburgh’s influence 

on the Liberty monitor while ignoring the gradient between the nearby, upwind Clairton 

monitor, which reinforces the well understood localized emission impact of the local 

source on the Liberty monitor. 

EPA Response: As explained in the TSD, the EPA has analyzed contribution from the 

entire CBSA for this area. The EPA’s decisions for inclusion of Allegheny County and 

not Washington County are set forth in the TSD, and have not changed based on 

supplemental analysis submitted by commenters in response to the intended designations. 

Emissions in Washington County are relatively low, less than a quarter of Allegheny 

County’s emissions. Washington County also has relatively low population, population 

density, and VMT. Furthermore, POM and EC, the largest components of the urban 

increment at the violating monitor, are low in Washington County. As explained in the 

TSD, the two point sources with emissions of greater than 500 tpy in Washington County 

have very low direct PM2.5 and VOC emissions, which indicates that any potential 

contribution to the POM and EC in the urban increment at the Liberty monitor is 

relatively low. 

The surrounding Allegheny County area is the largest source of relevant emissions in the 

area of analysis, and other factors such as meteorology and topography as further 

explained in the TSD justify inclusion of Allegheny County in the nonattainment area. In 

response to PADEP’s and ACHD’s supplemental analysis, the EPA conducted additional 

analysis to evaluate contribution from Allegheny County to the Liberty monitor. This 

additional analysis shows that based on a review of all days, as is appropriate for an 

annual NAAQS, rather than only high concentration days, there is contribution on some 

days and wind conditions from the surrounding Allegheny County area on the violating 

monitor. 

With respect to the commenters’ contention regarding concentration gradients between 

the nearby Clairton and Liberty monitors, the EPA agrees that this shows evidence of 

significant local contribution. However, as explained in detail in a previous response, the 

statute is clear in providing for inclusion in nonattainment areas of areas that “contribute” 

to the violations. A high or low monitored concentration at an attaining monitor does not 

by necessity preclude contribution from the surrounding area of analysis. This 

contribution is measured through a consideration of all available information, through a 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 14 of 68

five-factor analysis. The overwhelming local contribution from Liberty-Clairton sources 

does not preclude possible contribution from surrounding areas, and as further explained 

in the TSD, the five factor analysis indicates contribution from the remainder of 

Allegheny County outside the local Liberty-Clairton area. 

Comment: In response to the EPA’s August 19, 2014 120-day letter, PADEP and ACHD 

submitted information on historic trends for monitored annual means and design values 

for monitors in Allegheny County. The commenters contend that the information shows 

that the Liberty monitor is unique compared to all other monitors in Allegheny County, 

exhibiting both higher PM2.5 quarterly means and design values and poor correlation to all 

other county monitors, indicating local impact on this monitor by the nearby Clairton 

Coke Works. Commenters argue that the Liberty monitor is unique from other Allegheny 

County monitors due to this downwind proximity to the source, as well as 

microclimatological and topographical impacts related to the monitor’s location on a 

bluff over the river valley and the source. 

EPA Response: The EPA acknowledges the commenters assertion that the provided 

annual means and annual design value graphs for the Allegheny County monitors show 

that the Liberty monitor is higher than the other monitors in the county and follows a 

similar downward trend as the other monitor. This supports the EPA’s quarterly means 

analysis and conclusion that the Liberty monitor is influenced by the same seasonal 

patterns as the rest of the area but an additional local component is causing the 

exceedance in PM2.5 concentrations. However, section 107(d) of the CAA directs the 

EPA to designate an area nonattainment if it is violating the NAAQS, or if it is 

contributing to a violation of the NAAQS in a nearby area. Though the EPA agrees with 

the commenters that a local component is causing the exceedance of the NAAQS, the 

commenters do not disprove that emissions from Allegheny County are not contributing 

to the exceedance. As explained throughout the TSD, the EPA’s five factor analysis 

demonstrates contribution from Allegheny County to the violating Liberty monitor. The 

EPA acknowledges the topography and temperature inversions in the Liberty-Clairton 

area also probably cause local emissions to be trapped in this area and drive the violation 

of the NAAQS at this monitor. However, the statue compels the EPA to consider 

contribution to a violation of the NAAQS and not necessarily causation. In an attempt to 

better understand the meteorological impacts at the Liberty monitor, the EPA performed 

additional analysis of conditions at this site (see PA TSD pages 111 – 115). The EPA’s 

analysis also shows that under certain conditions on a large number days there is some 

degree of contribution from sources in the surrounding Allegheny County area to the 

violating Liberty monitor, therefore the topography and inversions do not preclude 

transport of emissions from outside this small area and that emissions from Allegheny 

County are capable of bypassing these features to impact the violating monitor. 

Comment: As part of their supplemental analysis submitted in response to the EPA’s 

August 19, 2014 120-day letter, PADEP and ACHD examined speciation data for select 

tri-state monitoring sites (both inside and outside the area of analysis) for the period 

between 2011-2013, in an attempt to characterize PM2.5 contribution at the violating 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 15 of 68

Liberty monitor. Commenters used a number of area monitors to assign allegedly 

incremental contribution from various parts of the area of analysis as regional 

background, the surrounding Pittsburgh MSA, the Pittsburgh urban area, and local 

sources within the Liberty-Clairton area. 

The commenters assert that the results of that analysis show that the Liberty monitor sees 

higher levels of elemental carbon and chlorine than other area monitors while other 

species, including sulfates and organic carbon, are more normalized in comparison of 

Liberty monitor levels to those seen at other tri-state monitors. Commenters assert that 

the allegedly incremental contribution analysis indicates that the surrounding MSA 

monitors show a large increment of organic carbonaceous material, indicative of a large, 

widespread contribution of area, mobile and point source emissions and that the rural 

background sites show large contributions of sulfate, nitrates and a portion of organic 

carbonaceous material, indicative of widespread regional transport. Commenters also 

assert that the Pittsburgh urban area contributes only an incrementally small portion of 

the total from the tri-state area to the Liberty monitor, and that the excess contribution 

generated nearby to the Liberty monitor contains high levels of carbon, sulfates and 

elemental carbon PM2.5 components, which can be attributed to the nearby industrial 

sources, such as the Clairton Coke Works source. 

EPA Response: The EPA’s approach to designations is to evaluate the entire CBSA and 

not differentiate between the MSA and the urban area within the CBSA. In addition, the 

EPA notes that the entire CBSA is appropriate for evaluating whether sources in this area 

are contributing to a violation within the County or within a nearby area. 

The EPA’s SANDWICH speciation data supports the commenters’ assertions with 

respect to some unique speciation results at the Liberty monitor in comparison to other 

area monitors. The EPA agrees that the commenters’ analysis of component speciation at 

the Liberty monitor compared to other area monitors shows heavy local industrial 

contribution of elemental carbon and chlorine components not seen at other monitors, as 

well as similar presence of components likely representing regional background (e.g., 

ammonium sulfates and ammonium nitrates). However, the analysis done by PADEP and 

ACHD does not account for high organic carbon and sulfate components at Liberty in 

comparison to these other area monitors which likely result from contribution to the 

Liberty monitor from sources outside the Liberty-Clairton local area and within 

Allegheny County. There are other mobile, area and point sources in Allegheny County 

with organic carbon and sulfate emissions that have the potential to contribute to the 

Liberty monitor. 

The commenters’ area contribution analysis appears to show some increment from within 

the Pittsburgh urban area to the violating Liberty monitor, indicating the existence of 

contribution to the violation from within Allegheny County. The commenters describe 

this contribution as an “incrementally small portion of the total,” but the EPA through its 

five factor analysis has determined that there is contribution from the Allegheny County 

area to the Liberty monitor sufficient to justify inclusion of the entire county in the 

nonattainment area, and the commenters have not rebutted this determination. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 16 of 68

After review of the commenters’ supplemental analysis to the EPA’s intended 

designation, while there is clearly contribution from local sources in the Liberty-Clairton 

area, it still appears from the evidence provided that there is some degree of contribution 

to the violation at the Liberty monitor from emission sources in Allegheny County based 

upon speciation data, emissions data, meteorology, and other factors as described in this 

TSD. 

Comment: In response to the EPA’s August 19, 2014 120 day letter, PADEP and ACHD 

provided updated 2013 emissions for sources generating over 500 tons per year in 

Allegheny County. Seven of the nine of these sources have decreased particulate matter 

and PM precursor emissions from 2011 to 2013, while emissions across the entire county 

were reduced emissions by 26.3%. Conversely, the Clairton Coke Works (e.g., the 

nearest major emissions source to the violating Liberty monitor) increased its emissions 

between 2011 and 2013, as a result of ongoing issues with some of its newer emissions 

controls. The nearby U.S. Steel Irvin Plant (2 miles from the Liberty monitor) also 

increased emissions, to a lesser degree, over that same period. Further, five coal-fired 

power plants inside the EPA’s area of analysis, but outside Allegheny County (two in 

Washington County, one in Greene County, and one in Preston County, WV) have 

deactivated since 2011. 

EPA Response: The EPA agrees with PADEP and ACHD that the most recent updated 

emissions data for sources in Allegheny County indicates that major point source facility 

emissions in Allegheny County have decreased, in their totality (except for the Clairton 

Coke Works and U.S. Steel Irvin facilities). However, while their impact on total 

emissions for Allegheny County are less in relation to total county emissions, these major 

facility revised emissions likely have some impact on the violating monitor 

Comment: PADEP and ACHD also provided Modeled Attainment Test Software 

(MATS) unmonitored area PM2.5 impacts from a baseline year of 2007 to a projected 

2014 (performed for the 2006 24-hour PM2.5 NAAQS SIP) to support their position. 

Commenters assert that the modeling results show distinct border for the extent of urban 

impacts in the Pittsburgh area compared to Liberty-Clairton impacts. To further 

demonstrate the allegedly unique emissions and the source of these emissions at the 

Liberty monitor, PADEP and ACHD submitted updated PMF source modeling. The 

commenters assert the Liberty monitor shows a large carbon-rich industrial source which 

is not present at other sites, and that the Liberty monitor also shows little motor vehicle 

emissions and that motor vehicle emissions from the Pittsburgh area are not transporting 

to the Liberty monitor. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 17 of 68

EPA Response: The EPA notes it does not rely on modeling forecasts when making 

decisions regarding NAAQS designations, as designations are based upon recent ambient 

air quality data and not future projections of air quality. The MATS modeling provided 

by PADEP and ACHD for 2007 and 2014 does support the commenters’ contention that 

ambient PM2.5 is concentrated in two separate plumes – one centered over the urban core 

of Pittsburgh and another separate plume over Liberty-Clairton area. However, the 

MATS modeling does not actually prove that there is no contribution from the remainder 

of Allegheny County to the Liberty monitor – instead it shows only that the largest 

sources of contribution at Liberty is from the local source. For reasons explained 

throughout the TSD, the five factor analysis demonstrates there is contribution from the 

remainder of Allegheny County to the violating monitor. 

The EPA acknowledges that a carbon-rich industrial source contributes to the Liberty 

monitor as shown in the PMF common source model analysis. The commenters’ 

provided PMF common source factor modeling analysis also demonstrates that the 

Liberty monitor detects source types similar to other area monitors for PM2.5 components 

typically associated with regional background (e.g., sulfates, nitrates and crustal). 

However, the PMF source factors for the Liberty monitor also show the appearance of 

PM2.5 components from motor vehicle and burning/cooking sources at levels similar to 

other area monitors. Given the lower population and vehicle-related activity in the 

vicinity of the Liberty monitor in comparison to other area monitors, the presence of 

motor vehicle and burning/cooking sources at levels similar to other area monitors does 

not disprove and actually could indicate contribution from outside the Liberty-Clairton 

area from at least those two source types. While the PMF modeling clearly shows a 

contribution from a local industrial sources, it does not rule out contribution from other 

sources in the County, particularly burning and motor vehicle sources. 

Comment: PADEP and ACHD provided additional Allegheny County population 

information in response to the EPA’s 120 day letter, focusing on population spatial 

allocation and population density. The agencies assert population in the metropolitan area 

is further removed from the violating monitor than is indicated by countywide data, and 

that the populations in the Liberty-Clairton area have been in decline by 13.4% for the 

period between 2000 and 2010. Commenters assert that this newly provided population 

data show that the majority of urban population-based area source and mobile source 

emissions created in the urban Pittsburgh portion of Allegheny County do not contribute 

significantly to violation at the Liberty monitor. 

EPA Response: While the commenters updated population data shows a more recent 

decline for the Liberty-Clairton area and that mobile emissions in this area contribute to a 

much lesser degree than local industrial sources, this does not eliminate the potential for 

emissions contribution to the violating Liberty monitor from the much larger source of 

population-based emissions from the more populous and heavily trafficked remainder of 

Allegheny County. Allegheny County has by far the largest population and population 

density, and vehicle miles travelled, relative to all other areas within the area of analysis 

for the violating Liberty monitor. As previously discussed, the statute is clear in 

providing for inclusion in nonattainment areas of areas that “contribute” to the violations. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 18 of 68

The EPA interprets the term “contributes” to mean contributes sufficiently to justify 

inclusion in the nonattainment area. As demonstrated by the five factor analysis in the 

TSD for the Allegheny County area and supplemental analyses performed in light of the 

commenters’ additional information, the EPA has determined that though there is 

significant contribution from the local sources to the violating monitor, there is also 

contribution from sources within the remainder of Allegheny County impacting the 

violating monitor justifying inclusion of the entire county in the nonattainment area. 

Comment: PADEP and ACHD provided additional meteorology data in response to the 

EPA’s 120 day letter. Commenters provided updated wind rose and temperature 

inversion information at the Liberty monitor site as well as several HYSPLIT trajectories 

for the area. Commenters assert that the EPA’s TSD only looked at airport data and did 

not evaluate local meteorological site at the Liberty Borough site. Commenters 

emphasize that the newly provided 2009-2013 wind rose at the Liberty Borough site 

demonstrates a preponderance of winds from the south through west with a dominant 

southwest component, further supporting their contention that the Liberty monitor is 

largely influenced by the Clairton Coke Works facility. PADEP and ACHD argue that the 

EPA did not address stagnation conditions at the Liberty monitor from frequent local 

inversion conditions that trap PM2.5 emissions at the monitor. The commenters provided 

inversion statistics for 2009-2013 to support this position that shows 40% of the days 

when data is available are impacted by inversions. 

EPA Response: The EPA agrees with the commenters that the regional wind direction 

closest to the Liberty monitor is from the south and the west with southwesterly 

components, however, there is still contribution from other sources as winds come from 

other directions. As discussed in the TSD, the wind rose closest to the Liberty monitor 

shows strong southerly and westerly components, with southwesterly and northwesterly 

components. The northwesterly component indicates that the highly urbanized Pittsburgh 

area is upwind of, and therefore contributing to, the Liberty monitor. Further, as 

discussed in previous responses, the EPA’s additional analysis (see PA TSD pages 111 – 

115) also shows that under certain conditions on a large number days there is some 

degree of contribution from sources in the surrounding Allegheny County area to the 

violating Liberty monitor. In addition, meteorological data from the Liberty Borough 

monitor is not regularly uploaded or quality assured by the EPA. Airport meteorological 

data has a higher level of quality assurance and the EPA must rely on highest quality 

available data when determining nonattainment boundaries. 

 As explained in previous responses as well as in the TSD, the EPA acknowledges the 

low level, diurnal inversions in the Liberty-Clairton area also probably cause local 

emissions to be trapped in this area and drive the violation of the NAAQS at this monitor. 

However, the statue compels the EPA to consider contribution to a violation of the 

NAAQS and not necessarily causation. The EPA’s analysis (see PA TSD pages 111 – 

115) also shows that under certain conditions on a large number days there is some 

degree of contribution from sources in the surrounding Allegheny County area to the 

violating Liberty monitor, therefore the topography and inversions do not preclude 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 19 of 68

transport of emissions from outside this small area and that emissions from Allegheny 

County are capable of bypassing these features to impact the violating monitor. 

Comment: A letter from the Allegheny Conference on Community Development to 

Dana Aunkst, Acting Secretary, at PADEP was submitted by PADEP. Allegheny 

Conference states that the EPA has inexplicably reversed its position recognizing the 

unique meteorology, topography and localized emissions in the Liberty monitoring area 

without justification. The commenter asserts that the EPA’s intended designation of all of 

Allegheny County is not supported by evidence. Allegheny Conference believes 

designating the entire county of Allegheny County as nonattainment would place 

unwarranted requirements on areas that do meet the 2012 PM2.5 NAAQS standard and 

urges the EPA to keep the nonattainment area to the current Liberty-Clairton boundaries. 

EPA Response: The EPA disagrees with the commenter’s contention that we have 

inexplicably reversed our historic position regarding the allegedly unique conditions 

affecting the Liberty monitor. Based on the evidence and its analysis regarding 

meteorology, topography, and other factors as explained in the TSD, the EPA has 

determined that sources within all of Allegheny County are contributing to the violating 

Liberty monitor and therefore justify inclusion of the entire county in the nonattainment 

area. Therefore, the requirements that result from this designation are warranted based 

upon the EPA’s determination that sources from within the entire Allegheny County 

contribute to the violating monitor. 

Comment: The Pennsylvania Department of Environmental Protection (PADEP) 

disagrees with the EPA’s intended two-county Allentown nonattainment area 

(Northampton and Lehigh Counties), instead arguing that the boundary should be limited 

to the county with the violating monitor (Northampton County) -- per PADEP’s July 

2014 updated recommendation. PADEP maintains that the violation at the Freemansburg 

monitor in Northampton County (Northampton County violating monitor) was caused by 

a fine particulate problem of an “extreme local nature” that was impacted by construction 

associated with the redevelopment of nearly 1,800 acres of the former Bethlehem Steel 

Corp site located 1.5 miles south of the Freemansburg monitor. PADEP conducted an 

additional analysis of available data and submitted supporting information to support its 

case on October 28, 2014. This includes updated air quality data, including an analysis of 

Allentown area monitors design value and annual means trends dating back to 2001, and 

correlation data comparing design values at the violating monitor with other area 

monitors. Finally, PADEP submitted updated 2013 emissions data for large point sources 

(over 500 tons per year) in the Allentown area and additional aerial photographs showing 

the Bethlehem Steel redevelopment site and its proximity to the violating Freemansburg 

monitor. 

PADEP contends that the spike in annual mean values at the Freemansburg monitor in 

2010 and 2011 is both temporary in nature and anomalous compared with data from other 

Allentown area monitors. PADEP argues that if the violation was the result of emissions 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 20 of 68

contribution from Lehigh County to the nearby Lehigh Valley monitor would show 

similar results to the violating Freemansburg monitor. 

In an attempt to demonstrate a unique set of circumstances at the Freemansburg monitor, 

PADEP also provided design value correlation data comparing that monitor to five other 

monitors in the EPA’s area of analysis. This data shows the strongest correlation between 

Freemansburg and Lehigh Valley monitors, however the relationship is much weaker in 

2011 (during the period of peak earth disturbance and construction activity at the former 

Bethlehem Steel site that lies just south of the Freemansburg monitor) versus in 2013 

after the conclusion of major site construction. 

EPA Response: PADEP has provided only anecdotal evidence that the construction 

activity at the Bethlehem Steel site is causing the spike in 2010 and 2011 design values at 

the nearby Freemansburg monitor, leading to the violation of the 2012 PM2.5 NAAQS for 

the 2011-2013 period. Speciation data and urban increment data set forth in the TSD 

clearly indicate that organic mass and elemental carbon are the main components of 

PM2.5 at the Freemansburg violating monitor. High organic mass and elemental carbon 

suggest that the sources of PM2.5 at the monitor are local in nature, likely due in large part 

to locally generated emissions from mobile, area or industrial sources, and not necessarily 

construction activity as the commenter contends. Given the proximity of the construction 

site to the violating monitor, the EPA would expect to see a higher proportion of crustal 

material as a result of the soil disturbance and construction activity. 

Furthermore, insofar as the commenter seeks to advance an argument that a local source 

was the cause or significant contributor to the violating monitor, section 107(d)(1) 

requires the EPA to designate area that are either violating the NAAQS or contributing to 

a violation of the NAAQS in a nearby area. The statute does not require the EPA to 

designate as nonattainment only those areas with sources that are causing a violation of 

the NAAQS. Also, the EPA has interpreted “contribution” to encompass a concept that is 

broader than just “significant contribution.” The EPA interprets the term “contributes” to 

mean contributes sufficiently to justify inclusion in the nonattainment area, and the 

EPA’s multifactor test with the various analytical tools is intended to assure an objective 

evaluation of the appropriate facts on a case by case basis in each area. The EPA has 

considered multiple factors of analysis, and has applied the same analysis to all counties 

considered in the area of analysis as outlined in the TSD. The EPA’s analysis justifies 

inclusion of the Northampton and Lehigh counties in the nonattainment area, as 

emissions in these counties are contributing sufficiently to the violating monitor. 

Additionally, Pennsylvania argues that its submitted monitor design value trends for three 

area monitors exhibit similar patterns dating back to 2001 (except for the 2010 and 2011 

peak construction period, during which time the violating Freemansburg shows a 3 ug/m3 

peak above the Lehigh Valley monitor). However, the Allentown monitor discontinued 

operation in 2005 and the Lehigh Valley monitor only commenced operation in 2010, 

leaving the period between 2005 and 2010 with no other monitor in the Allentown area 

with which to compare values to Freemansburg. Given the lack of continuously operating 

monitors in the area, it is impossible to draw the types of comparisons that Pennsylvania 

is attempting to draw between design values for the 2010-11 period. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 21 of 68

Pennsylvania states that if emissions from the nearby Lehigh County were contributing to 

the Freemansburg monitor violation, then they would expect the Lehigh Valley monitor 

annual means would also have increased significantly. The EPA contends that the lack of 

more than one violating monitor in an area is not dispositive evidence of whether a 

nearby area or county contributes to the violation of another monitor, as the violation 

may be the result of cumulative or aggregate impacts from the surrounding area. 

Pennsylvania argues that its correlation comparisons between regional monitors in and 

around the Allentown area to the Freemansburg monitor show the strongest correlation 

between the Freemansburg monitor and the 1.5 mile distant Lehigh Valley monitor, 

followed closely by the 35 mile distant Reading monitor. Further, PADEP argues that the 

correlations between Freemansburg and each of these monitors is much stronger in 2013 

than it was in 2011, during the height of the Bethlehem Steel site construction. The EPA 

would expect a high proportion of crustal PM2.5 emissions components at the violating 

monitor if the 2010-2011 spike (based on the state’s provided historic trend analysis) 

were the result of earth disturbance construction-related activity. Speciation data for the 

Freemansburg monitor provided by the EPA in the TSD does not show high levels of 

crustal material and PADEP’s additional speciation analysis show high crustal material 

on only a small number of high monitor value days. 

The Commonwealth’s analysis of correlations between Freemansburg and other area 

monitors establishes a similar correlation relationship between Freemansburg to the 

distant Reading monitor with that of Freemansburg to the nearby Lehigh Valley monitor, 

including a similarly strong relationship in 2013 versus that of the 2011, during the time 

representing heavy construction activity near the Freemansburg monitor. The EPA 

believes such a similarly strong correlation between Reading and Freemansburg 

(compared with that of Freemansburg to Lehigh Valley) should not exist, if the 

Commonwealth’s hypothesis that the cause of the spike in monitor values in 2010-2011 

is the result of only local construction activity. Instead the state argues that the 35-mile 

distant Reading monitor exhibits similar design value relationships to Freemansburg due 

to its topographical similarity to the Freemansburg site. Given the primary nature of 

crustal ejecta (i.e., a lack of secondary PM2.5 component formation) and its tendency 

towards dispersion and dilution over distance, the EPA believes the correlation 

relationships further support our contention that the violating monitor is showing regional 

level contribution of organic and elemental carbon, most likely associated with mobile, 

area, and industrial sources. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 22 of 68

The Commonwealth also provided updated 2013 emissions data for large point sources 

(emitting more than 500 tons per year) in Northampton and Lehigh Counties. However, 

the provided data shows that the preponderance of emissions reductions from major point 

sources in the area come from Northampton County sources, with the exception of one 

source in Lehigh County. The reduction of point source emissions in Northampton 

County does not negate the EPA’s position in the TSD that there is a significant 

contribution of non-point (area and mobile) emissions from both Northampton and 

Lehigh Counties. 

After consideration of the analyses provided by PADEP, the EPA continues to believe the 

nonattainment boundary for the Allentown area should remain the two counties of 

Northampton and Lehigh. 

Comment: Northampton County is expected to attain the PM2.5 standard, based on 2014 

design values, prior to the effective date of the EPA’s final designations. Once the 2014 

data is received, PADEP will request withdrawal of the Allentown area as attaining the 

2012 PM2.5 NAAQS. 

EPA Response: The designation decision is based on available, certified data at the 

current time and reflects air quality at the current time, rather than projections of future 

air quality. The 2012 PM2.5 NAAQS designations utilize the most recent certified design 

value data which is for 2011-2013. See Data Considerations under General Issues above. 

The EPA notes requests from the State to withdraw an area from the nonattainment 

designation will be considered through the appropriate redesignations process. 

3.2.2. EPA Region IV 

Comment: Alabama Department of Environmental Management (ADEM) requested that

the entire State, including Russell County, be designated as attainment, consistent with 

their March 2014 initial designation recommendation. They identified that the EPA will 

be basing designations on the 2011-2013 monitoring period. The design value for the 

Russell County monitor for this period is 11.2 μg/m3

. They note that while they 

understand that the Columbus, Georgia, monitors have insufficient data to make a 

designation determination for the 2011-2013 monitoring period, the data from the Russell 

County monitor for this period has been quality assured and accepted by the EPA as valid 

and in compliance with the 2012 annual PM2.5 NAAQS. For this reason, they continue to 

request that rather than defer designations for Russell County, the EPA designate Russell 

County as attainment, with the understanding that the designation may need to be revised 

if the Columbus, Georgia, monitors fail to comply with the standard for the 2012-2014 

monitoring period. 

EPA Response: The EPA appreciates ADEM’s response to the EPA’s intended 

designations for Alabama areas as identified in the EPA’s August 19, 2014, letter. The 

EPA acknowledges that Alabama has valid monitoring data for the Russell County 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 23 of 68

monitor for 2011-2013 indicating an attaining design value for the 2012 primary annual 

PM2.5 NAAQS at that monitoring location. However, Russell County is located in the 

core-based statistical area (CBSA) for the Columbus-Phenix City Area, and the Georgia 

monitor within this CBSA does not have sufficient data for the 2011-2013 time period for 

the EPA to make a determination that this part of Georgia is in compliance with the 2012 

primary annual PM2.5 NAAQS. Furthermore, based on the EPA’s technical analysis (see 

the memorandum entitled “Georgia Deferred Areas - Air Quality Designations for the 

2012 PM2.5 National Ambient Air Quality Standard (SAN 5706)” in the EPA’s docket for 

this rulemaking) for the Columbus-Phenix City Area and the fact that there is currently 

not enough data for the EPA to make a determination on whether the monitors in the 

Georgia portion of this area would have design values below the 2012 primary annual 

PM2.5 standard, at this time the EPA lacks sufficient information to determine whether 

Russell County is contributing to a potential violation in the Columbus-Phenix City Area. 

For these reasons, and because there are indications that this area will have sufficient data 

in the near future which will allow the agency to make a determination, the EPA is 

deferring the designation for Russell County while we await forthcoming data. 

Comment: Georgia Environmental Protection Division (GEPD) agrees with the EPA’s 

intention stated in the 120-day letter to defer initial area designations under the 2012 

annual PM2.5 NAAQS for Georgia counties in the Augusta, Columbus, Savannah, 

Valdosta, and Washington County areas (with the exception of Dougherty County, which 

is part of the Albany, GA area and was incorrectly included as a “deferred” county in the 

August 19, 2014 letter but not in supporting documentation). GEPD also requests that the 

EPA similarly defer initial area designations for Georgia counties in the Atlanta, 

Brunswick, and Albany areas that were identified in the August 19, 2014, letter as 

intended “unclassifiable” areas. GEPD also respectfully requests that the non-Georgia 

counties associated with the Augusta and Columbus areas be designated attainment. 

EPA Response: The EPA appreciates GEPD’s response to the EPA’s intended 

designations for Georgia areas as identified in the EPA’s August 19, 2014, letter. The 

EPA agrees with GEPD’s response and is now deferring designations for the Georgia 

counties in the Albany, Atlanta and Brunswick Areas as well as the Georgia counties 

identified in the Augusta, Columbus, Savannah, Valdosta, and Washington County 

Areas. Currently, there is not enough data to support a conclusion regarding the 

likelihood that these counties are not violating the 2012 annual PM2.5 NAAQS or not 

contributing to nearby areas that may be violating the NAAQS. However, there are 

indications that these areas will have sufficient data to make a determination in the near 

future. 

 

The deferred designation of the Albany Area includes Dougherty County. Although the 

EPA identified Dougherty County in the deferred Albany Area in the Agency’s August 

19, 2014, letter, the EPA intended to designate Dougherty County as “unclassifiable” in 

that letter. Given the lack of complete data from the Dougherty County monitor, the EPA 

has now decided to defer the designation for this county while the EPA awaits 

forthcoming data that will allow the EPA to determine the extent to which portions of the 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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Albany Area are violating the 2012 primary annual PM2.5 NAAQS, or contributing to any 

nearby areas that may be violating that NAAQS. 

Regarding GEPD’s request for the EPA to designate as “attainment” the non-Georgia 

counties associated with Augusta and Columbus Areas, the EPA lacks sufficient 

information at this time to assess the likelihood that these non-Georgia counties are 

potentially contributing to violations that may exist in either the Augusta or Columbus 

Areas. Accordingly, the EPA is deferring designations for Richmond County, South 

Carolina (in association with the Augusta Area) and Russell County, Alabama (in 

association with the Columbus Area). The EPA is deferring these counties based on the 

EPA’s technical assessment (see the memorandum entitled “Georgia Deferred Area Air 

Quality Designations for the 2012 PM2.5 National Ambient Air Quality Standard (SAN 

5706) in the EPA’s docket for this rulemaking) of the likelihood of contribution to 

potential violations in the Augusta and Columbus Areas, on the fact that there is currently 

not enough data for the EPA to make a determination regarding whether certain areas 

comply with the 2012 primary annual PM2.5 NAAQS, and on indications that these areas 

will have sufficient data in the near future that will allow the Agency to make these 

determinations. South Carolina provided a letter of support for the EPA’s use of its 

deferral authority in this case. 

Comment: The South Carolina Department of Health and Environmental Control 

(DHEC) agrees with the EPA’s intention stated in the 120-day letter to defer initial area 

designations under the 2012 annual PM2.5 NAAQS for Aiken County, South Carolina as 

part of the deferred area of Augusta, GA-SC. DHEC expects that 2014 monitoring data 

will show that the area meets the standard. 

EPA Response: The EPA appreciates the commenters’ support.

Comment: The Tennessee Department of Environment and Conservation recommends 

that the EPA defer initial area designations for all areas in Tennessee, except for 

Hamilton, Marion and Sequatchie Counties in the Chattanooga area that the EPA 

identified in the August 19, 2014 letter as intended “unclassifiable/attainment.” 

EPA Response: The EPA appreciates TDEC’s response to the intended designations for 

Tennessee areas as identified in the EPA’s August 19, 2014, letter. The EPA agrees with 

TDEC’s response and based on its analysis of the information available, the EPA is now 

deferring designations for all counties in Tennessee, except for Hamilton, Marion and 

Sequatchie Counties in the Chattanooga Area. Currently, there is not enough data in these 

areas to make determinations regarding the areas’ compliance with the 2012 primary 

annual PM2.5 NAAQS. However, there are indications that these areas will have sufficient 

data in the near future which will allow the Agency to make these determinations. As 

indicated in the EPA’s August 19, 2014 letter and as recommended by TDEC, the EPA is 

designating the Hamilton, Marion, and Sequatchie Counties in the Chattanooga Area as 

“unclassifiable/attainment” for the 2012 primary annual PM2.5 NAAQS. The EPA is 

making the final designation of “unclassifiable/attainment” for these counties because the 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 25 of 68

EPA has sufficient data for the counties in the CBSA for the Chattanooga Area (i.e., 

Hamilton, Marion, and Sequatchie Counties in Tennessee and Catoosa, Dade, and Walker 

Counties in Georgia) to make this final designation. 

Comment: Sierra Club opposes the EPA’s proposal to designate the Atlanta and 

Columbus Areas in Georgia as unclassifiable and believes that the EPA must designate 

these areas as nonattainment. According to Sierra Club, the EPA cannot designate these 

areas as unclassifiable because doing so would be against available data, the EPA 

regulations, and the EPA guidance and would subject Georgians to considerable health 

risks, including risks of increased mortality rates. In support of its position, Sierra Club 

states that: 

“The Atlanta and Columbus areas have a 2010-2012 design value that is valid and shows 

nonattainment, and no valid design value that contradicts this finding. Further, these areas 

include some of the most densely populated areas of the state. 

“Georgia’s Recommendation concludes that that the entire state be classified 

attainment/unclassifiable. However, that suggestion relies on both an incorrect period to 

determine the design value and inappropriate predictions on the part of the state. Further, 

it misrepresents the data available to the state. On December 13, 2013, the only complete 

three years of data that was available to the Georgia Environmental Protection Division 

was the data from 2010, 2011, and 2012. Under the 2012 Design Value, monitors in the 

Atlanta and Columbus areas violate the NAAQS. Although Georgia tries to hide this fact 

by performing a series of educated guesses as to 2013 monitor readings, the data is clear 

that these areas violated the NAAQS under the 2012 design value. 

“The April 2013 the EPA Memo directs states to use 2010-2012 data for state 

recommendations. That same memo then states that that 2013 monitor data may be used 

by the EPA to determine NAAQS designations only if valid data is available to inform 

the 2013 design value. In Georgia’s case, there is not enough data for the EPA to rely on 

the 2013 design value. As a result, the EPA’s use of the 2013 design value would be 

contrary to its own regulations and guidance. Further, it is the EPA’s directive under the 

Clean Air Act to protect both human health and the environment. As indicated in the 

EPA’s decision to defer designation for other parts of Georgia, it is appropriate to take 

cautionary approach to protect human health. 

“To err on the side of protecting human health and provide for an adequate margin of 

safety, the EPA’s data conventions require less stringency to determine that an area is 

nonattainment when there is incomplete data. Under Appendix N to 40 CFR Part 50, 

“years with at least 11 creditable samples in each quarter shall [] be considered valid if 

the resulting annual mean or resulting annual PM2.5 NAAQS quarter shall [] be 

considered valid if the resulting annual mean or resulting annual PM2.5 NAAQS [design 

value] (rounded according to the conventions of section 4.3 of this appendix) is greater 

than the level of the applicable primary or secondary annual PM2.5 NAAQS.” 40 C.F.R. 

Part 50, Appendix N, at 4.1(b). Put another way, so long as the mean results in a violation 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 26 of 68

of the NAAQS, a year’s data is considered valid if there are at least 11 creditable samples 

in each quarter of that year. 

“It is clear that areas in Georgia violated the NAAQS under the 2012 design value, and 

that the 2013 design value is not valid due to data completeness issues. However, both 

the Georgia Recommendation and the EPA Response contain discussions about trends on 

PM2.5 emissions and PM2.5 precursor emissions. To the extent that either agency relies on 

these general trends to inform NAAQS designations, that reliance is inappropriate and 

misguided. 

“Georgia’s assertion that lower PM2.5 levels are due to real and permanent emission 

reductions for PM2.5 and PM2.5 precursors is completely contrary to recent permitting 

actions taken by the State, which found that such reductions were not permanent. For 

example, when it applied to convert Plant Yates to natural gas in 2013, Georgia Power 

asked the Georgia Environmental Protection Division (“GaEPD”) to adjust its baseline 

emissions rate time period because of decreased use of its coal units. Georgia Power 

claimed the decreased use was due to the Great Recession, which “officially began 

December 2007,” and natural gas prices, which “reached historic lows and [caused] the 

use of many coal-fired plants [to] decline[] drastically.” Id. at 2. Georgia EPD concurred 

with Georgia Power’s assessment. Georgia EPD cannot credibly claim that emissions 

reductions are permanent, or even that general trends can be assumed going forward, 

after finding that the same reductions are due to cyclical changes in the economy and 

natural gas prices. Further, Georgia relies on Georgia Rule 391-3-1-.02(2)(sss) (‘Georgia 

Rule (sss)’). However, Georgia Rule (sss) has not been formally incorporated into the 

State Implementation Plan as approved by the EPA. If Georgia does intend to rely on this 

rule to avoid nonattainment, it must make the rule federally enforceable by incorporating 

it into the SIP.” 

EPA Response: In the information that the Agency released on August 19, 2014, 

providing the intended designations for the Atlanta and Columbus Areas (amongst other 

areas nationwide), the EPA stated its intention to designate the Atlanta Area as 

unclassifiable and to defer the designation of the Columbus Area. The EPA is now 

deferring designations for a number of Georgia counties in the Atlanta Area, as well as 

for the Alabama and Georgia counties in the Columbus-Phenix City Area. The EPA does 

not currently have enough data to make determinations regarding either the areas’ 

compliance with the 2012 primary annual PM2.5 NAAQS, or the relative likelihood that 

portions of these areas are contributing to potential nearby violations. However, because 

the EPA expects that all monitors within these areas will have sufficient data to 

promulgate designations in the near future, the Agency is merely deferring designations 

for these areas. 

For the reasons discussed above, the EPA is deferring initial area designations for both 

the Atlanta and Columbus Areas pursuant to its authority under section 107(d)(1)(B) of 

the Clean Air Act. The EPA expects that complete data for these areas are forthcoming, 

and will promulgate designations for these areas when it has sufficient information to do 

so. Designations for these Areas will be based on actual data reflecting conditions during 

the period relevant to the designation process; they will not be based on projected 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 27 of 68

emission trends. The EPA provided information regarding emissions trends in its August 

19, 2014, letter to the State of Georgia and associated technical support documents to 

better inform the public of the levels of particulate matter pollution in the Atlanta and 

Columbus-Phenix City Areas over time. Any forward-looking reductions relied upon in 

the designation process will have to be based on actual, enforceable, and permanent 

reductions. Finally, the EPA did not rely on Georgia Rule (sss) in making the decision to 

defer these areas. 

3.2.3. EPA Region V 

Comment: Ohio EPA believes that Lake County should be designated as attainment. The 

monitoring ID 39-085-0007 in Lake County is in attainment. Lake County is located east 

of Cuyahoga County where the nonattainment monitors are located. Therefore, an 

easterly wind pattern would be necessary to cause emissions in Lake County to contribute 

to violations in the Cleveland area. However, as indicated by the meteorological wind 

data US EPA reported “there is a pattern across the area of predominantly south to west 

winds, mostly at mid-level speeds of 4 to 10 meters per second, suggesting that potential 

emission sources in the south through-west upwind direction should be considered for 

analysis.” In addition, the eastern monitor in Cuyahoga County is also in attainment 

(located between Lake County and the nonattainment monitor).

The EPA also reported that Lake County emits the greatest amount of direct PM2.5 and 

precursors in the Cleveland area including 44% of the SO2 emissions. The Cleveland 

Electric Illuminating Company Eastlake Plant (Eastlake Power Plant) contributed 

approximately 93% of the total point source emissions evaluated for Lake County and is 

located 18 miles from the nearest nonattainment monitor. For nearly 2 years (2013 and 

2014 emission reporting years) the largest units at the Eastlake Power Plant, units 4 (240 

MW) and 5 (597 MW), have been shutdown (generators have been removed and cannot 

resume operation). The facility has already made significant reductions in PM2.5 and 

PM2.5 precursors to date. A proposed shutdown of the remaining units 1, 2 and 3 (132 

MW each) by April 2015 has been submitted for approval to PJM Interconnection 

Regional Transmission Organization (RTO). The proposed shut down of the remaining 

units is included in the PJM Interconnection RTO Generator Deactivation Summary 

Sheets available at http://www.pjm.com/planning/generationdeactivation/gdsummaries.aspx and will result in further dramatic reductions in direct 

PM2.5 and precursor emissions prior to the impending PM2.5 annual NAAQS attainment 

date. Eastlake Power Plant has also informed Ohio EPA they are in agreement with 

zeroing out their SO2 emissions for the purpose of future attainment demonstration 

modeling for the 2010 SO2 NAAQS SIP document due in spring of 2015. 

Ohio EPA’s recommendation that all of Lake County should be designated as attainment 

is further supported by HYSPLIT KDE (HYbrid Single-Particle Lagrangian Integrated 

Trajectory Kernel Density Estimation) plots presented in the US EPA Cleveland TSD. 

The KDE plots show that for each quarter evaluated (2010-2012) Carmeuse Lime, 

Incorporated - Grand River Operations, which is 28 miles away from the nearest 

nonattainment monitor, is not located within a KDE grid with a frequency of 75% or 
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December 17, 2014 

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higher of observed trajectory endpoints. Painesville Municipal Electric Plant, which is 

also 28 miles from the nearest nonattainment monitor, only had an estimated density in 

the 75% or higher range during the second quarter of years 2010-2012, when the 

quarterly average at all of the Cuyahoga County monitoring sites was below 12.0 μg/m3

. 

If the EPA insists on including Lake County in the Cleveland nonattainment area, Ohio 

EPA strongly urges that only the western portion that encompasses the area including and 

west of the Eastlake Power Plant. Although Ohio EPA disagrees commuter travel 

between Lake County and Cuyahoga County would warrant including Lake County in the 

nonattainment area, designating only the following townships in the western portion of 

Lake County would capture the majority of commuter VMT emission between Lake and 

Cuyahoga Counties: Eastlake, Lakeline, Timberlake, Wickliffe and Willowick. These 

townships also surround the Eastlake Power Plant. However, as presented in Ohio EPA's 

original recommendations, although the number of commuters traveling into Cuyahoga 

from Lake County was among the highest evaluated, only 5.2% of the workers working 

in Cuyahoga County commute in from Lake County. Ohio EPA believes this small 

percentage of vehicle source emissions does not warrant inclusion of any portion of Lake 

County in the Cleveland nonattainment area. 

EPA Response: The EPA agrees with Ohio’s conclusion that Lake County should not be 

designated nonattainment based on contribution to violations of the NAAQS in Cuyahoga 

County. The EPA’s preliminary conclusion to include Lake County as nonattainment was 

primarily because the EPA believed at the time that Lake County emitted the greatest 

amount of direct PM2.5 and precursors in the Cleveland area – over 5,000 tpy more than is 

emitted in Cuyahoga County. This was primarily because the EPA believed at the time 

that Cleveland Electric Illuminating Company Eastlake Power Plant (Eastlake) had the 

highest combined emissions of any source in the Cleveland area, and also because it was 

only 18 miles from the design value monitor in Cleveland. However, for nearly two years 

the two largest units have been shut down and the generators have been removed and 

cannot resume operation. These shutdowns are permanent and enforceable. As a result of 

these shutdowns, NOx emissions have been reduced by 6,204 tons per year and SO2

emissions have been reduced by 43,264 tons per year since 2013. In addition, the 

remaining three smaller units are scheduled to be shut down by April 2015, although this 

likely future reduction did not factor into the EPA’s analysis. This reduction in emissions 

from the already shut down units makes Lake County go from being the county with the 

greatest amount of direct PM2.5 and precursors in the Cleveland area to one of the 

counties with below average emissions in the Cleveland area. 

Lake County is east of and downwind from the violating monitors in Cleveland, based on 

wind roses generated by the EPA for the Cleveland area, which show a pattern of 

predominantly south to west winds – mostly at mid-level speeds of 4 to 10 meters per 

second. HYSPLIT KDE plots for the Cleveland area indicate a greater frequency of 

trajectories passing over grid cells to the west and south. In addition, only 5.2% of 

Cuyahoga workers commute from Lake County. While the EPA previously believed that 

emissions from the Eastlake Power Plant were substantial enough to overcome these 

countervailing factors and warrant Lake County’s inclusion in the Cleveland 

nonattainment area, the updated information from Ohio indicates that this is no longer the 

case. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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In conclusion the EPA agrees with Ohio that Lake County should be designated as 

attainment because of the very large, permanent, and enforceable decrease in point source 

emissions identified by Ohio, because Lake County is downwind of the violating 

monitors in Cleveland, and because there are only a moderate number of Lake County 

workers commuting to Cleveland. 

Comment: Ohio EPA recommends that Lorain County be designated as attainment. 

Lorain County is located west of Cuyahoga County and the Cleveland area nonattainment 

monitors. Monitor 39-093-3002 located centrally along the northern border of Lorain 

County (6 miles from Avon Lake Power Plant) and monitor 39-035-1002 on the west side 

of Cuyahoga County between Lorain and the violating monitors are both in attainment. 

Avon Lake Power Plant is the only major point source in Lorain County. It is located in 

northeast corner of Lorain County approximately 19 miles from the nearest 

nonattainment monitor. Avon Lake Power Plant announced June 30, 2013 that it will be 

converting to natural gas; Ohio EPA granted a Mercury Air Toxics Toxic Standards 

(MATS) extension to April 16, 2016 for the facility. Ohio EPA expects that this 

conversion will result in dramatic PM2.5 and PM2.5 precursor emissions from the Avon 

Lake Power Plant, therefore Ohio EPA believes Lorain County should be designated as 

attainment. 

The VMT in Lorain County (2,787,828,581) were the second highest in the evaluation 

area, but still significantly lower than those of Cuyahoga County (8,534,134,941). 

However, as presented in Ohio EPA's original recommendations, only 5.9% of the 

workforce in Cuyahoga County commutes in from Lorain County. Ohio EPA believes 

this small percentage of vehicle source emissions does not warrant inclusion of any 

portion of Lorain County in the Cleveland nonattainment area. 

EPA Response: The EPA disagrees that Lorain County should be designated as 

attainment. Lorain County is west of and upwind of the violating monitors in Cleveland. 

This is evidenced by the wind roses that the EPA generated for the Cleveland area, which 

show a pattern of predominantly south to west winds - mostly at mid-level speeds of 4 to 

10 meters per second. In addition, HYSPLIT KDE plots for the Cleveland area indicate a 

greater frequency of trajectories passing over grid cells to the west and south. Therefore, 

all of the direct PM2.5 and precursor emissions from point, area and mobile sources can 

impact the Cleveland monitors. 

Although the Avon Lake Power Plant (Avon Lake) will be converting to natural gas this 

will not occur until April, 2016 and there will still be significant NOx emissions after the 

conversion occurs. Unlike the shutdown which has actually occurred in Lake County, this 

scheduled conversion will not take place until well after the designation process and it is 

therefore difficult to establish the impact of this conversion on Cleveland PM2.5 levels. 

Although only 5.9% of the workforce in Cuyahoga County commutes in from Lorain 

County, the VMT in Lorain County, at 2.8 million, is one of the highest in the Cleveland 

area. This is significant because, unlike for Lake County, the vehicular emissions in 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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Lorain County will have an impact on the Cleveland monitors because Lorain is 

commonly upwind of Cuyahoga County and Cleveland. 

In summary, Lorain should be designated as nonattainment for PM2.5 because it has the 

third highest amount of direct PM2.5 and precursors in the Cleveland area, the conversion 

to natural gas at Avon Lake will not take place until April, 2016, it is commonly upwind 

of the violating monitors in Cleveland and has significant VMT. 

Comment: Ohio EPA believes that Summit County should be designated as attainment. 

Both of the monitoring sites (monitor 10391530017, 391530023) located in Summit 

County are in attainment. US EPA considered Summit County in the nonattainment 

analysis for the Cleveland, Ohio area as well as the Canton Massillon, Ohio area. The 

previous Ohio EPA recommendation and analysis submitted on December 13, 2013 still 

holds true for Summit’s impact on violations in the Cleveland nonattainment area. 

While Ohio EPA agrees that Summit County is best suited in the Canton-Massillon 

nonattainment area as opposed to the historically designated Cleveland area, Ohio EPA 

still asserts that Summit County should not be designated nonattainment. The three major 

point sources located in Summit are within 4 miles of the two Summit County attaining 

monitors. Wind data indicates that the majority of the winds near these three major point 

sources are westerly to southerly which would move pollutants away from the 

nonattainment monitor in Stark County. The majority of the northerly winds observed in 

Summit County are low speed ranging from 2-6 mph. Back-trajectories of the first, 

second, third and fourth maximum concentration days over three years (2010-12) at the 

Stark County nonattainment monitor 39-151-0017 were analyzed using NOAA's Model, 

HYSPLIT. The back trajectory simulations also included the trajectories of exceedance 

days of 24-hr PM2.5 standard for years 2010-12 at the same monitor. The purpose of 

trajectory analyses was to determine the cause of violation by simulating the flow of 24-

hour air trajectory patterns in the backward mode. The analysis indicates that none of the 

24 hour backward trajectory patterns originated from areas directly north or northeast of 

the monitor indicating that the trajectories were not influenced by Summit County 

sources. Although Summit County has the highest VMT for the counties evaluated in the 

Canton-Massillon area, as indicated in Ohio EPA's original recommendations, only 5.5% 

of the workers commuting into Stark County travel from Summit County. Ohio EPA 

believes that this small percentage of commuters in combination with the wind trends and 

beck trajectory data support a Summit County attainment designation. 

EPA Response: The fact that the Summit County monitors are attaining the annual 

PM2.5 standard does not prove that there is no contribution from the area to violations in 

Cleveland or Canton. Summit County has both significant emissions and VMT, with the 

second highest total emissions, third highest direct PM2.5 emissions and highest VMT 

among the counties in the area of analysis for Canton, and the third highest total 

emissions and second highest VMT among the counties in the area of analysis for 

Cleveland. 

Further, the HYSPLIT modeling provided by Ohio EPA was limited in that it only 

considered trajectories for the four highest concentration days and the 24-hour 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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exceedance days for the 2010-2012 time period. For the 2012 annual NAAQS, the 

monitoring data for the entire calendar year (including on days that are below the level of 

the NAAQS) are part of the mathematical calculation of whether a monitor is 

nonattainment or not. Therefore, wind directions during periods that do not have high 

ambient levels are also relevant. Nevertheless, it can be informative to evaluate the days 

with monitored concentrations that exceed the value of the standard, 12.0 μg/m3,since 

those are the days that make a larger contribution towards a violation. The EPA analyzed 

all of the days with concentrations exceeding 12.0 μg/m3

 during the 2011-2013 time 

period at the Canton design monitor, using the HYSPLIT model to simulate back 

trajectories. Of the days with concentrations exceeding the value of the annual standard at 

the Canton monitor, 37% of the days have trajectories passing over Summit County. In 

conjunction with the emissions, meteorology, and VMT data for Summit County, this 

data indicate that Summit County contributes to the violations monitored in both Canton 

and Cleveland. Therefore, the EPA continues to conclude that Summit County should be 

designated as nonattainment because it contributes to violations of the NAAQS in nearby 

areas. 

Ohio EPA indicates that Summit County is best suited for the Canton nonattainment area. 

The EPA agrees that Summit County is more appropriately included in the CantonMassillon nonattainment area than the Cleveland area. The major point sources in 

Summit County are in the southern portion of the county, closer to the violating monitor 

in Canton than to the violating monitor in Cleveland. In addition, kernel density plots for 

Canton show a high density of trajectories covering the southern portion of Summit 

County. For these reasons, the EPA is designating Summit County as part of the CantonMassillon area even though Summit County also contributes to the Cleveland area. 

Comment: Ohio EPA believes that the entire Wayne County should be designated as 

attainment. The cumulative VMT in Wayne County (1,192,145,098 miles in 2012) is less 

than 1/3 of the VMT in Stark County (3,838,738,336 miles in 2012), and as shown in 

Table 5 of the Ohio TSD, only 1.3% of the workers commuting into Stark County 

commute in from Wayne County. Ohio EPA believes this small percentage of vehicle 

source emissions does not warrant inclusion of Warren County in the nonattainment area. 

The major point sources in Wayne County are located approximately 18-24 miles westnorthwest of the nonattainment monitor in Stark County. Ohio EPA believes that point 

sources located at this great of a distance are not significantly contributing to violations at 

the Stark County monitors, especially when considering there are two major Stark 

County point sources located within 3 miles of the nonattainment monitor. As reported by 

US EPA, the Department of Public Utilities, City of Orrville (Orville Power Plant) 

contributes 74% of the major point source total direct PM2.5 and precursor emissions 

evaluated in Wayne County. This facility is subject to the Boiler Maximum Achievable 

Control Technology (MACT) rules established in 40 CFR 63 Subpart DDDDD. It is also 

likely that the Orville Power Plant will be evaluated under the SO2 NAAQS. Under these 

regulations, Ohio EPA believes that the Orville Power Plant will experience significant 

reductions in PM2.5 and PM2.5 precursors prior to the impending PM2.5 attainment date. If 

US EPA insists on designating Wayne County as nonattainment, Ohio EPA believes that 

only Orrville Township in Wayne County should be designated as nonattainment similar 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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to the approach used for designating Ashtabula Township as nonattainment for the 2006 

PM2.5 NAAQS. In this approach the emissions in Ashtabula Township (a portion of 

Ashtabula County, Ohio) were found to be primarily attributable to Cleveland Electric 

Illuminating's Ashtabula plant and therefore only Ashtabula Township (rather than all of 

Ashtabula County) was designated as nonattainment. Using this approach, Orrville 

Township would be the only portion designated as nonattainment in Warren County. 

EPA Response: The EPA disagrees that Wayne County should be designated as 

attainment. Wayne County is west of the monitor in Stark County and wind roses, 

pollution roses and HYSPLIT modeling all indicate that sources in Wayne County 

contribute to monitored PM2.5 levels at the Stark County monitor. While VMT may not 

be particularly high in Wayne County, total emissions are higher in Wayne County than 

in Stark County. The majority of the emissions can be attributed to three point sources. 

These sources are located in the north-east quarter of the county comprised of Baughman, 

Chippewa, Green, and Milton townships and the portion of Norton City located within 

Wayne County. 

Comment: We oppose the EPA's proposal to override Indiana Department of 

Environmental Management (IDEM's) recommendation. The EPA cites no issues with 

IDEM's data, which is complete and shows attainment across all monitors in both 

counties. Instead, the EPA proposes to change the designation for Lake and Porter 

counties to “unclassifiable” due to irregularities with Illinois' sampling program.

Specifically, the EPA proposes to designate Lake and Porter counties as “unclassifiable” 

on the premise that it cannot determine whether those counties may be contributing to a 

violation in Illinois, if such a violation exists. All monitors in both Indiana counties 

demonstrate compliance with the 2012 PM2.5 NAAQS. The EPA has not challenged the 

validity of that data. Nor has the EPA identified a single violating monitor where it 

contends Lake and Porter counties are “contributing” to nonattainment. Under these 

circumstances, the CAA mandates an “attainment” designation for both counties.

The EPA lacks authority to designate Lake and Porter counties as “unclassifiable.” The 

CAA provides three NAAQS designation categories: (1) nonattainment, (2) attainment, 

and (3) unclassifiable. By explicitly defining each category, Congress limited the 

discretion of states and the EPA in making designations. The EPA must designate as 

nonattainment “any area that does not meet (or that contributes to ambient air quality in a 

nearby area that does not meet) the [NAAQS] for the pollutant.” The EPA must designate 

as attainment “any area (other than an area identified in clause (i)) that meets the 

[NAAQS] for the pollutant.” Areas may be designated "unclassifiable" only when the 

area “cannot be classified on the basis of available information as meeting or not meeting 

the [NAAQS] for the pollutant.” Lake and Porter counties are meeting the NAAQS and 

have not been linked to any nonattaining monitor, making nonattainment and 

unclassifiable designations improper. Therefore the only designation category the CAA 

allows for Lake and Porter counties is “attainment.”

The EPA correctly concluded that Lake and Porter counties do not meet either criterion 

for a “nonattainment” designation. Without either (1) a nonattaining monitor in Lake 
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December 17, 2014 

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and/or Porter counties or (2) a nonattaining monitor outside Lake and Porter counties to 

which these counties are contributing, Lake and Porter counties do not fit the definition 

of “nonattainment.” Similarly, Lake and Porter counties do not meet the criteria for 

“unclassifiable.” An “unclassifiable” area is defined as one in which a lack of information 

prevents the EPA from determining if the area is “meeting or not meeting the [NAAQS].” 

There is no lack of information on the attainment status of Lake and Porter counties.

Unlike the definition of “nonattainment,” the statute does not allow the EPA to designate 

an area as unclassifiable because of its potential to contribute to an unclassifiable area. 

The plain statutory text tellingly omits any reference to contribution, instead focusing 

only on whether the county itself is meeting the NAAQS. There is no lack of data or 

ambiguity on that point to support an unclassifiable designation. Pursuant to CAA § 

107(d)(l)(A)(ii), the EPA must designate an area as “attainment” if it “meets the 

[NAAQS] for the pollutant” and does not satisfy the criteria for nonattainment. That is 

precisely the situation in Lake and Porter counties. The EPA has undisputed information 

demonstrating that all monitors in Lake and Porter counties are attaining the 2012 PM2.5

NAAQS. The EPA has not identified a single nearby monitor that is demonstrating 

nonattainment, and therefore cannot conclude that Lake and Porter counties are 

contributing to nonattainment elsewhere. 

Only an attainment designation is consistent with the CAA's provisions for adjusting 

designations as new information becomes available. Specifically, CAA § 107(d)(3)-(4) 

allows the redesignation of Lake and Porter counties if valid data from Illinois later 

indicates a NAAQS violation and if the EPA demonstrates that Lake and/or Porter 

counties are contributing to that violation. In the meantime, the EPA must make 

designations based on the information it has. That information permits only one 

designation for Lake and Porter counties: attainment. 

EPA Response: The commenter properly quotes the criteria in Clean Air Act section 107 

for designating areas nonattainment, attainment, or unclassifiable, but the commenter 

misinterprets the criteria for being designated attainment. At issue is two counties that 

themselves attain the air quality standard but that contribute to concentrations nearby that 

may be violating the standard. The commenter argues that a particular portion of the 

Chicago area (Lake and Porter Counties, Indiana) should be designated attainment 

because the two counties a) meet the standard and b) have not been identified as a 

nonattainment area. However, the EPA believes that a more appropriate interpretation of 

the criteria for an attainment designation is whether the entire area (including any portion 

of the area with emissions that contribute to concentrations in the area) is attaining the 

standard. Since the Chicago area cannot be determined to be an area that is meeting the 

standard, the Chicago area (including all portions that contribute to concentrations in the 

Chicago area) does not quality for designation as attainment. 

The EPA designates entire areas as nonattainment, attainment, or unclassifiable; the EPA 

does not promulgate separate designations for separate portions of areas. For example, in 

2005, the EPA designated a Chicago PM2.5 nonattainment area that included Lake and 

Porter Counties in Indiana as well as part or all of eight Illinois counties as a single 

combined area. This designation defined a planning area, triggering the applicability of 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 34 of 68

an assortment of planning requirements under Section 172 and other sections of Part D 

among other things to provide a unified plan by which control measures throughout the 

area would be considered and adopted as appropriate to pursue attainment throughout the 

area. Thus, interpreting the word “area” in Section 107 as meaning the entire area that is 

designated as a unit is more consistent with the manner in which the EPA has historically 

promulgated designations and is more consistent with other elements of the Clean Air 

Act that apply planning requirements to areas as a whole. Addressing areas as a whole 

also provides a more logical outcome to the designation process in cases like this: where, 

as here, the area does not warrant a nonattainment designation because the area cannot be 

classified as violating the standard, and the area does not warrant an attainment 

designation because the area cannot be classified as attaining the standard, the area 

clearly warrants a designation that the area “cannot be classified on the basis of available 

information as meeting or not meeting” the standard. 

Nothing in the Clean Air Act suggests either that the EPA should designate separate 

portions of the Chicago area separately or that the provisions of 107 should be interpreted 

as yielding a large area if the area is violating the standard but a small area if the area is 

attaining the standard or if the area is unclassifiable. To the contrary, once a 

nonattainment area is defined, the planning provisions apply to the nonattainment area as 

a whole, wherein the planning addresses a unified area that includes all the 

interconnected locations within an area that are experiencing violations and contributing 

to those violations. The commenter evidently envisions balkanizing these areas into an 

unlimited number of separate pieces, with each piece designated without regard to the 

interconnections between these pieces, but this approach is inconsistent with the use of 

the word “area” and the planning process provided in the Clean Air Act. Similarly, the 

provisions for redesignating nonattainment areas (“or portions thereof”) to attainment are 

contingent on satisfaction of various prerequisites, where the relevant provisions must 

address air quality across the entire area. For example, the EPA cannot redesignate a 

portion of a nonattainment area if permanent and enforceable measures are yielding 

attainment in only a portion of the area. By the same logic, Section 107(d)(1) must be 

interpreted to provide for an attainment designation only if the entire area is attaining the 

standard and to provide for an unclassifiable designation if the full area cannot be 

determined to be violating or attaining the standard. 

The commenter highlights the absence of reference to contributing area in the criteria for 

an unclassifiable designation. However, this has significance only with the commenter’s 

use of the word “area.” Interpreting “area” to mean just one of several interconnected 

locations, and accepting the commenter’s interpretation that areas contributing to a 

potentially contributing to violations cannot be designated unclassifiable unless air 

quality is uncertain in those particular locations, yields the illogical result that the size of 

unclassifiable areas would generally be much smaller than the size of the area if it were 

designated nonattainment. In contrast, interpreting “area” to mean all of the locations that 

collectively influence whether the collective set of locations meets the air quality 

standard yields a more coherent interpretation of the three designations in Section 

107(d)(1) that is more consistent with the terminology and planning requirements 

elsewhere in the Clean Air Act that result from these designations. With this broader 

interpretation of the word “area,” Section 107(d)(1)(i) clarifies that nonattainment areas 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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must include contributing locations as well as violating locations, Section 107(d)(1)(ii) 

clarifies that locations that are meeting the standard but are part of a broader area that is 

violating the standard cannot be designated attainment, and Section 107(d)(1)(iii) 

specifies that any area (which in context would include all the interconnected source and 

receptor locations) that cannot be determined to be violating or attaining the standard 

would be designated unclassifiable. The EPA believes that Lake and Porter Counties 

contribute to concentrations in Cook County and elsewhere in the Chicago area, and the 

EPA believes more generally that the set of locations with source-receptor relationships 

that warrant being included in the area that could be called the Chicago area would 

include Lake and Porter Counties. Since the EPA is unable to determine whether this area 

meets or does not meet the standard, the EPA believes that Section 107(d)(1) provides for 

the Chicago area, including Lake and Porter Counties, to be designated as unclassifiable.

Comment: The EPA may not invalidate data for one purpose and rely on it for another.

The EPA suggests that “the available air quality data suggest that the spatial distribution 

of exposure to PM2.5 is similar to the distribution the EPA found in 2005, when it 

promulgated the Chicago 1997 PM2.5 nonattainment area.” However, the EPA already 

determined that the “available air quality data” in Illinois is invalid. The EPA may not 

invalidate data for designating Illinois counties and at the same time arbitrarily use that 

invalid data as the basis for designating Indiana's counties. Once the EPA determined that 

the Illinois data was invalid, that data could no longer be considered. It would be 

arbitrary for the EPA to second-guess Indiana's detailed and carefully considered 

recommendation based on data the EPA has already deemed unreliable. 

EPA Response: The commenter is misreading the EPA’s statements regarding the 

available air quality data. The EPA’s technical support document for its intended actions 

for Illinois and associated areas stated, “While the Illinois air quality data are not 

sufficiently complete to provide a reliable indication of the magnitude of concentrations, 

the available air quality data suggest that the spatial distribution of exposure to PM2.5 is 

similar to the distribution the EPA found in 2005.” Thus, as is clear from the technical 

support document, the EPA believes that insufficient air quality data are available to 

determine whether a violation exists at any site in Illinois, but the EPA believes that 

sufficient air quality data are available to assess the spatial distribution of concentrations 

in the Chicago area. (Indeed, the EPA makes these data available for purposes such as 

these under parameter code 88501 in its Air Quality Subsystem (AQS).) Furthermore, 

even if the EPA were to disregard recent air quality data, the similarity of the distribution 

of emissions in 2002 (as examined in 2005) and in 2011 (examined more recently) lend 

further support to the view that the distribution of concentrations recently is similar to the 

distribution in 2002 to 2004. As a result, and given that “a review of the distribution of 

emissions, population, and vehicle travel also shows a similar distribution” in the older 

and newer data sets, the EPA continues to believe that the same locations are contributing 

to high annual average concentrations now that contributed to high concentrations in 

2002 to 2004. While the EPA has insufficient information to determine whether the high 

concentrations are above or below the standard, the EPA has sufficient information to 

identify the range of locations that may be considered either to be experiencing 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 36 of 68

concentrations potentially above the standard or to be contributing to these concentrations 

potentially above the standard. 

Comment: One commenter notes that the EPA's proposed designation of Lake and 

Porter Counties as "unclassifiable" is arbitrary and capricious. The EPA's sole basis for 

designating Lake and Porter counties as “unclassifiable” is theory that “if the Chicago 

area is violating the NAAQS, the area that the EPA finds would likely be contributing to 

that violation would likely be the same area as the EPA found in 2005 to contribute to 

violations of the 1997 PM2.5 NAAQS [which includes Lake and Porter counties].” That 

speculation is unsupported by any facts in the record and ignores the fact (noted in Table 

2 of the Illinois TSD) that the western most Lake County PM2.5 monitor (site number 18-

089-2010), which is less than five-thousand feet from the Illinois and Indiana border, had 

PM2.5 design values of 11.0 and 10.6 μg/m3 during 2010-2012 and 2011-2013, 

respectively. These values are well under the PM2.5 NAAQS of 12 μg/m3

. The EPA has 

failed to demonstrate that current attainment levels in Lake and Porter counties are linked 

to any non-attaining monitor. 

The EPA may not rely on a 2005 NAAQS analysis when updated guidance and data are 

available. The EPA's claim that “a review of the distribution of emissions, population, 

and vehicle travel also shows a similar distribution of these parameters [to 2005]” 

similarly fails to support an unclassifiable designation for Lake and Porter counties. 

Stating conclusively that some characteristics in the region appear similar to those in

2005, without providing any citations or support, falls far short of demonstrating that 

Lake and Porter counties are responsible for unidentified potential air quality problems in 

Illinois. First, the current “distribution of emissions” cannot be determined without valid 

monitoring data in Illinois. Second, having similar population and vehicle travel profiles 

in 2014 and 2005 does not demonstrate that Lake and Porter counties are “likely” 

contributing to a potential NAAQS violation in Illinois. That is particularly true because 

no specific Illinois monitor exists that would allow the EPA to evaluate such links. In 

addition, the EPA's proposed designations fail to address how the factors relied on in 

2005 relate to U.S. EPA's 2013 guidance on Area Designations for the 2012 Revised 

Annual Fine Particle National Ambient Air Quality Standard ("2013 Guidance"). The 

2013 Guidance includes factors such as air quality data, location of sources, growth rate 

and patterns, weather, geography and jurisdictional boundaries, none of which are 

addressed in the Illinois TSD. The EPA has made no mention of whether these other 

factors are comparable to 2005, and indeed has done no analysis whatsoever to determine 

the present-day impacts of Lake and Porter counties on Cook County, Illinois. In fact, the

EPA's assumptions fail to take into account important developments affecting the 

concentration and distribution of PM2.5 in this region, such as the closing of the massive 

coal-fired State Line Generating Plant in 2012 and the continual decrease in PM2.5

ambient concentrations since 2009. The EPA cannot ignore such developments. The EPA 

is required to demonstrate a rational connection between the facts found and the choices 

made when making NAAQS determinations. The EPA has not analyzed the actual 

relationship between emissions in Lake and Porter counties and PM2.5 concentrations in 

Illinois, nor has the EPA even identified a NAAQS violation in Illinois that would 

warrant such an inquiry. Basing designations on unfounded speculation over what 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 37 of 68

impacts Lake and Porter counties might have on a potential NAAQS issue in Illinois 

when those counties specifically show attainment would result in an arbitrary and 

capricious designation.

EPA Response: The EPA’s technical support document for its PM2.5 designations for 

Illinois and associated areas provides the EPA’s rationale for defining the Chicago area 

for purposes of these designations. The commenter is incorrect in claiming that the EPA 

has not analyzed the relationship between emissions in Lake and Porter Counties and 

PM2.5 concentrations in Illinois and in claiming that the EPA’s designation is based on 

“unfounded speculation.” Nevertheless, in alleging the absence of the information that is 

provided in the docket for the proposed rulemaking, the commenter mostly chooses not to 

provide comments on the merits of the analysis the EPA did provide and fails to identify 

objections to the specific elements of the analysis that the EPA did conduct. 

The commenter objects to the approach of defining an unclassifiable area based on 

hypothesizing a violation and reviewing the locations that would contribute to such a 

violation, but the commenter does not suggest any alternative approach for defining the 

contributing portions of an area that might violate the standard or express views on how 

the EPA might better determine the boundaries of an area with the potential to violate the 

standard, including the associated locations that contribute to concentrations where the 

standard may be violated. (Comments interpreting Clean Air Act Section 107 to provide 

for the exclusion of contributing areas from areas designated unclassifiable are addressed 

above.) The EPA continues to believe that we have properly designated as unclassifiable 

both the locations with the potential for violating the standard and the locations that 

contribute to concentrations where violations may be occurring, and the EPA continues to 

believe that the most appropriate means of defining the contributing portions of such 

areas is to examine available information, including information on air quality, emissions, 

meteorology, jurisdictional considerations, and topography, to determine what locations 

might be expected to contribute to the violations if in fact they are occurring. 

The commenter asserts that the EPA’s conclusion ignores the existence of data in Lake 

County, less than a mile from Cook County, showing concentrations somewhat below the 

standard. The commenter does not explain his concept of linking monitoring data, and the 

commenter provides no explanation as to why concentrations at about 90 percent of the 

standard should be treated as evidence that Lake and Porter Counties do not contribute to 

concentrations in Cook County that may exceed the standard. The EPA need not identify 

a specific monitor in Cook County as violating the standard to conclude that if a monitor 

in Cook County is violating the standard, Lake and Porter Counties are contributing to 

the violation. 

The commenter questions whether the analysis that the EPA completed in 2005 addresses 

the criteria that the EPA identified in its 2013 guidance. In fact, though the 2013 

guidance uses a different organization of its recommended factors than the 2003 guidance 

used in preparing the 2005 designations, the underlying information and analytical 

approaches recommended in the 2013 guidance are very similar to those recommended in 

the 2003 guidance. Thus, the analyses completed in 2005 effectively address the factors 

identified in the 2013 guidance. In addition, the EPA reviewed more recent data, 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 38 of 68

concluding that these data (reviewed in accordance with the 2013 guidance) justified the 

same area definition as the EPA promulgated in 2005. 

Although the relevant recent data are available in the docket, for convenience the key 

relevant data are repeated here, organized according to the factors identified in the 2013 

guidance. As will be discussed below, the EPA finds that these data support the same 

boundaries of the Chicago area as the EPA promulgated in 2005. 

Factor 1, Air quality: Although the data are insufficient to provide an adequately reliable 

indication of whether the air quality standards are being violated in the Chicago area, the 

data indicate that the highest concentrations are observed in Cook County. Therefore, the 

greatest potential for violations exists in Cook County, and the EPA may reasonably 

promulgate an unclassifiable area that identifies a planning area that includes Cook 

County and the area around Cook County that contributes to PM2.5 concentrations in 

Cook County, so long as this area also includes the Chicago area locations with the 

potential to violate the standard. 

The EPA agrees as a general matter that air quality has been improving in much of the 

Midwest, but that does not mean that Lake and Porter Counties are not contributing to 

any violation that may be occurring elsewhere in the Chicago area. 

Factor 2, Emissions: For this factor, the EPA reviewed data from the 2011 National 

Emissions Inventory (NEI) version 1 (see 

http://www.epa.gov/ttn/chief/net/2011inventory.html). For each county in the area of 

analysis, the EPA examined the magnitude of county-level emissions reported in the NEI. 

These county-level emissions represent the sum of emissions from the following general 

source categories: point sources, non-point (i.e., area) sources, nonroad mobile, on-road 

mobile, and fires. The EPA also looked at the geographic distribution of major point 

sources of the relevant pollutants.1

 Significant emissions levels from sources in a nearby 

area indicate the potential for the area to contribute to monitored violations. 

To further analyze area emissions data, the EPA also developed a summary of direct 

PM2.5, components of direct PM2.5, and precursor pollutants, which is available at 

http://www.epa.gov/pmdesignations/2012standards/docs/nei2011v1pointnei2008v3count

y.xlsx. 

Evaluating the components of direct PM2.5 and precursor gases can help identify specific 

sources or source types contributing to elevated concentrations at violating monitoring 

sites and thus assist in identifying appropriate area boundaries. In general, directly 

emitted particulate organic carbon (POC) and VOCs2

 contribute to PM2.5 organic mass 

                                                            

1

 For purposes of this designations effort, “major” point sources are those whose sum of PM precursor 

emissions (PM2.5 + NOx + SO2 + VOC + NH3) are greater than 500 tons per year based on NEI 2011v1. 

2

 As previously mentioned, nearby VOCs are presumed to be a less important contributor to PM2.5 OM than 

POC. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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(OM); directly emitted EC contributes to PM2.5 EC; NOX, NH3 and directly emitted 

nitrate contribute to PM2.5 nitrate mass; SO2, NH3 and directly emitted sulfate contribute 

to PM2.5 sulfate mass; and directly emitted crustal material and metal oxides contribute to 

PM2.5 crustal matter. 3,4 The EPA believes that the quantities of those nearby emissions as 

potential contributors to the PM2.5 violating monitors are somewhat proportional to the 

PM2.5 chemical constituents in the estimated urban increment. Thus, directly emitted POC 

is more important per ton than SO2, partially because POC emissions are already PM2.5 

whereas SO2 must convert to PM2.5 and not all of the emitted SO2 undergoes this 

conversion. 

This review of emissions information addresses annual emissions rather than seasonal 

emissions for several reasons. First, emissions of significant pollutants are relatively 

constant throughout the year, so that there are insufficient seasonal emission variations to 

warrant a season-by-season review. Second, as noted above, except for the seasonal 

variations in nitrate concentrations, the composition of the urban increment appears to be 

relatively constant throughout the year. The cold month concentrations of nitrate are 

linked to cold month emissions of NOx, but warm month emissions of NOx are also 

significant due to their contribution to the photochemical reactions that form secondary 

particulate matter. For these reasons, the EPA analyzed annual emissions and concluded 

that analysis of seasonal emissions was unnecessary. 

Table 1 provides a county-level emissions summary (i.e., the sum of emissions from the 

following general source categories: point sources, non-point (i.e., area) sources, nonroad 

mobile, on-road mobile, and fires) of directly emitted PM2.5 and precursor species for the 

county with the violating monitoring site and nearby counties considered for inclusion in 

the Chicago area. Table 2 summarizes the directly emitted components of PM2.5 for the 

same counties in the area of analysis for the Chicago area. 

Table 1. County-Level Emissions of Directly Emitted PM2.5 and Precursors 

(tons/year) 

County NH3 NOX PM2.5 SO2 VOC 

Cook Co, IL 3307 108980 14387 16883 87924 

Lake Co, IN 976 37838 6539 24464 16249 

Will Co, IL 1694 28003 5646 34592 14309 

Du Page Co, IL 751 23194 2731 566 19215 

Lake Co, IL 623 20107 3197 10747 19148 

Porter Co, IN 2852 17222 3737 16745 6283 

                                                            

3 See, Seinfeld J. H. and Pandis S. N. (2006) Atmospheric Chemistry and Physics: From Air Pollution to 

Climate Change, 2nd edition, J. Wiley, New York. See also, Seinfeld J. H. and Pandis S. N. (1998) 

Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 1st edition, J. Wiley, New 

York. 

4

 USEPA Report (2004), The Particle Pollution Report: Current Understanding of Air Quality and 

Emissions through 2003, found at: http://www.epa.gov/airtrends/aqtrnd04/pm.html. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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Kane Co, IL 994 11808 2068 290 9761 

Jasper Co, IN 2955 9960 2041 19513 2872 

La Porte Co, IN 1832 8069 1945 13419 5016 

La Salle Co, IL 1895 7680 2932 713 5024 

Mc Henry Co, IL 1116 6605 1494 130 5845 

Kenosha Co, WI 1228 6493 1197 1029 4249 

Kankakee Co, IL 1315 4325 1777 163 3859 

Grundy Co, IL 688 3780 1158 157 2263 

Kendall Co, IL 745 3065 964 56 3191 

Key: 

NH3 – Ammonia 

NOX – Nitrogen Oxides 

PM2.5 – Directly emitted PM2.5

SO2 – Sulfur Dioxide 

VOC – Volatile Organic Compounds 

Table 2 breaks down the direct PM2.5 emissions value from Table 1 into their 

components. Table 2 summarizes the directly emitted components of PM2.5 for the same 

counties in the area of analysis for the Chicago area. 

Table 2. County-Level Emissions for Components of Directly Emitted PM2.5

(tons/year) 5

County, State POM EC PSO4 PNO3 Crustal Residual Direct 

Cook Co, IL 4538 2695 447 51 2675 3982 14387

Lake Co, IN 1343 763 771 32 1488 2143 6539

Will Co, IL 1033 665 339 14 1548 2047 5646

Du Page Co, IL 1178 658 55 11 326 503 2731

Lake Co, IL 982 498 108 10 669 931 3197

Porter Co, IN 792 610 218 26 954 1137 3737

Kane Co, IL 682 380 32 7 463 504 2068

Jasper Co, IN 284 110 90 2 732 824 2041

La Porte Co, IN 511 207 60 3 553 611 1945

La Salle Co, IL 551 198 112 6 1101 964 2932

Mc Henry Co, IL 456 222 19 4 399 394 1494

                                                            

5

 Data are based on the 2011 and 2018 Emissions Modeling Platform Data Files and Summaries 

(ftp://ftp.epa.gov/EmisInventory/2011v6/v1platform) available at: 

http://www.epa.gov/ttn/chief/emch/index.html#2011 (accessed 02/26/14). 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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Kenosha Co, WI 622 130 26 2 190 226 1196

Kankakee Co, IL 446 141 16 3 660 511 1777

Grundy Co, IL 231 115 27 3 376 406 1158

Kendall Co, IL 219 108 12 3 329 293 964

Key: 

PNO3 – Primary Nitrate 

PSO4 – Primary Sulfate 

EC – Elemental Carbon 

POM – Primary Organic Matter 

Crustal – Crustal Material 

Using the previously described relationship between directly emitted and precursor gases 

and the measured mass to evaluate data presented in Tables 1 and 2, the EPA identified 

the following components warranting additional review: directly emitted organic matter, 

elemental carbon, NOx, and SO2. The EPA then looked at the contribution of these 

constituents of interest from each of the counties included in the area of analysis as 

shown in Tables 3a-d. 

Table 3a. County-Level Particulate Organic Matter Emissions (tons/year) 

State County POM % of Area Cum % 

Illinois Cook, IL 4538 33% 33%

Indiana Lake, IN 1343 10% 42%

Illinois DuPage, IL 1178 8% 51%

Indiana Will, IL 1033 7% 58%

Illinois Lake, IL 982 7% 65%

Illinois Porter, IN 792 6% 71%

Illinois Kane, IL 682 5% 76%

Wisconsin Kenosha Co 622 4% 81%

Illinois LaSalle, IL 551 4% 85%

Indiana La Porte, IN 511 4% 88%

Indiana McHenry, IL 456 3% 91%

Illinois Kankakee, IL 446 3% 95%

Illinois Jasper, IN 284 2% 97%

Illinois Grundy, IL 231 2% 98%

Illinois Kendall, IL 219 2% 100%
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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Table 3b. County-Level Elemental Carbon Emissions (tons/year) 

County EC % of Area Cum % 

Cook, IL 2695 36% 36%

Lake, IN 763 10% 46%

Will, IL 665 9% 55%

DuPage, IL 658 9% 64%

Porter, IN 610 8% 72%

Lake, IL 498 7% 79%

Kane, IL 380 5% 84%

McHenry, IL 222 3% 87%

La Porte, IN 207 3% 89%

LaSalle, IL 198 3% 92%

Kankakee, IL 141 2% 94%

Kenosha, WI 130 2% 96%

Grundy, IL 115 2% 97%

Jasper, IN 110 1% 99%

Kendall, IL 108 1% 100%

Table 3c. County-Level Nitrogen Oxides Emissions (tons/year) 

County NOX % of Area Cum % 

Cook, IL 108980 37% 37%

Lake, IN 37838 13% 49%

Will, IL 28003 9% 59%

DuPage, IL 23194 8% 67%

Lake, IL 20107 7% 73%

Porter, IN 17222 6% 79%

Kane, IL 11808 4% 83%

Jasper, IN 9960 3% 87%

La Porte, IN 8069 3% 89%

LaSalle, IL 7680 3% 92%

McHenry, IL 6605 2% 94%

Kenosha, WI 6493 2% 96%

Kankakee, IL 4325 1% 98%

Grundy, IL 3780 1% 99%

Kendall, IL 3065 1% 100%

Table 3d. County-Level Sulfur Dioxide Emissions (tons/year)

County SO2 % of Area Cum % 

Will, IL 34592 25% 25%

Lake, IN 24464 18% 42%

Jasper, IN 19513 14% 56%

Cook, IL 16883 12% 68%
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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Porter, IN 16745 12% 80%

La Porte, IN 13419 10% 90%

Lake, IL 10747 8% 98%

Kenosha, WI 1029 1% 99%

LaSalle, IL 713 1% 99%

DuPage, IL 566 0% 99%

Kane, IL 290 0% 100%

Kankakee, IL 163 0% 100%

Grundy, IL 157 0% 100%

McHenry, IL 130 0% 100%

Kendall, IL 56 0% 100%

In addition to reviewing county-wide emissions of PM2.5 and PM2.5 precursors in the area 

of analysis, the EPA also reviewed emissions from major point sources located in the 

area of analysis. The magnitude and location of these sources can help inform 

nonattainment boundaries. Table 4 provides facility-level emissions of direct PM2.5, 

components of direct PM2.5, and precursor pollutants (given in tons per year) from major 

point sources located in the area of analysis for the Chicago area. Table 4 also shows the 

distance from the facility to the DV monitor for the area.

Table 4. NEI 2011 v1 Point Source Emissions (tons/year) 

County Facility Name 

Distance 

to 

Monitor 

(mi) NH3 NOx PM 2.5 SO2 VOC Total 

Cook, IL 

Corn Products 

International Inc (031012ABI) 13 1 665 463 1,569 511 3,208 

Cook, IL 

Fisk Electric 

Generating Station (031600AMI) 14 0 1,098 199 4,133 1 5,432 

Cook, IL OHare Airport (ORD) 2 5,261 139 578 961 6,939 

Cook, IL Midway Airport (MDW) 14 1,150 22 133 195 1,499 

Cook, IL Ford Motor Co (031600AAR) 26 1 18 27 0 650 696 

Cook, IL 

Saint-Gobain 

Containers Inc (031069AAI) 26 1 412 78 158 21 670 

Cook, IL 

Crawford Electric 

Generating Station (031600AIN) 12 0 1,893 281 6,545 1 8,721 

Cook, IL Koppers Inc (031300AAJ) 12 1 115 4 857 106 1,083 

Grundy, IL 

Equistar Chemicals LP 

(063800AAC) 45 0 549 178 19 454 1,200 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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County Facility Name 

Distance 

to 

Monitor 

(mi) NH3 NOx PM 2.5 SO2 VOC Total 

Kankakee, 

IL 

Natural Gas Pipeline 

Co of America (091811AAB) 65 0 495 10 0 32 537 

Lake, IL 

Waukegan Electric 

Generating Station (097190AAC) 29 1 2,563 718 9,931 2 13,214 

La Salle, IL 

Pilkington North America 

(099825AAG) 68 0 625 107 303 10 1,045 

La Salle, IL 

Owens-Brockway 

Glass Container Inc (099490AAD) 76 0 308 65 138 22 533 

La Salle, IL Illinois Cement Co (099030AAZ) 76 3 897 32 89 32 1,052 

Will, IL 

Oxbow Midwest 

Calcining LLC (197803AAK) 23 145 130 7,003 0 7,278 

Will, IL 

Exxon Mobil Oil Corp 

(197800AAA) 41 207 1,720 249 1,317 429 3,922 

Will, IL 

Midwest Generation LLC 

(197809AAO) 35 1 6,314 1,391 17,034 5 24,745 

Will, IL 

Will County Electric 

Generating Station (197810AAK) 25 1 2,227 392 8,301 2 10,922 

Will, IL 

CITGO Petroleum Corp 

(197090AAI) 24 232 685 144 513 443 2,017 

Jasper, IN 

NIPSCO - R.M. SCHAHFER 

(00008) 68 1 7,367 747 19,352 161 27,627 

Lake, IN 

STATE LINE ENERGY LLC 

(00210) 26 1 7,005 412 8,044 83 15,544 

Lake, IN Indiana Harbor East (00316) 31 19 4,813 526 2,874 1,123 9,355 

Lake, IN 

MITTAL STEEL (ISG INDIANA 

HARBOR WEST) (00318) 31 14 1,601 711 860 84 3,270 

Lake, IN COKENERGY INC. (00383) 31 85 4,892 4,977 

Lake, IN 

BP PRODUCTS NORTH 

AMERICA, WHITING R (00003) 29 17 2,548 427 697 2,118 5,806 

Lake, IN 

ANR PIPELINE NAT GAS_CO 

ST. JOHN STATION (00069) 42 482 12 0 26 520 

Lake, IN 

INDIANA HARBOR COKE 

(00382) 31 17 859 154 1,898 2 2,930 

Lake, IN 

U S STEEL CO GARY WORKS 

(00121) 38 103 4,313 1,529 4,202 1,168 11,315 

Lake, IN CARMEUSE LIME INC (00112) 33 1,688 31 313 13 2,045 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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County Facility Name 

Distance 

to 

Monitor 

(mi) NH3 NOx PM 2.5 SO2 VOC Total 

La Porte, IN 

NIPSCO - MICHIGAN CITY 

(00021) 53 24 1,433 388 13,353 88 15,287 

Porter, IN ArcelorMittal Burns Harbor (00001) 44 29 8,289 2,065 13,843 497 24,723 

Porter, IN 

NIPSCO - BAILLY STATION 

(00002) 45 20 1,975 187 2,560 67 4,809 

Kenosha, 

WI 

Wisconsin Electric Power 

Pleasant Prairie Power Plant 

(230006260) 40 636 2,498 130 928 124 4,316 

The commenter observes that the State Line plant shut down in 2012. Although the 

commenter has not provided evidence as to whether this shutdown is permanent or 

enforceable, the EPA has reviewed this information. The EPA notes that other facilities 

(such as the ArcelorMittal Burns Harbor facility) in Lake and Porter Counties have 

greater emissions, and the EPA concludes that emissions even with that plant shutdown 

are sufficient to conclude that Lake and Porter Counties are a contributing portion of the 

Chicago area. 

The EPA also evaluated the population and vehicle use characteristics and trends of the 

area as indicators of the probable location and magnitude of non-point source emissions. 

Rapid population growth in a county on the urban perimeter signifies increasing 

integration with the core urban area, and indicates that it may be appropriate to include 

the county associated with area source and mobile source emissions as part of the 

nonattainment area. Table 5 shows the 2000 and 2010 population, population growth 

since 2000, and population density for each county in the area. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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Table 5. Population Growth and Population Density. 

County 

Population 

2000 

Population 

2010 

% 

Change 

from 

2000 

 Land 

Area 

(Sq. 

Miles) 

Population 

Density 

(per Sq. 

Mile) 

% of 

Area 

Cumulative

% 

Cook, IL 

 

5,376,741 5,199,377 -3.3%

 

946 

 

5,498 54% 54%

DuPage, IL 

 

904,161 918,186 1.6%

 

334 

 

2,752 9% 63%

Lake, IL 

 

644,356 704,303 9.3%

 

448 

 

1,574 7% 70%

Will, IL 

 

502,266 678,883 35.2%

 

837 

 

811 7% 77%

Kane, IL 

 

404,119 516,034 27.7%

 

520 

 

992 5% 83%

Lake, IN 

 

484,564 496,112 2.4%

 

497 

 

998 5% 88%

McHenry, IL 

 

260,077 309,223 18.9%

 

604 

 

512 3% 91%

Kenosha, WI 

 

149,577 166,632 11.4%

 

273 

 

611 2% 93%

Porter, IN 

 

146,798 164,565 12.1%

 

418 

 

394 2% 94%

Kendall, IL 

 

54,544 115,257 111.3%

 

321 

 

360 1% 96%

La Salle, IL 

 

111,509 113,816 2.1%

 

1,135 

 

100 1% 97%

Kankakee, IL 

 

103,833 113,502 9.3%

 

677 

 

168 1% 98%

LaPorte, IN 

 

110,106 111,432 1.2%

 

598 

 

186 1% 99%

Grundy, IL 

 

37,535 50,103 33.5%

 

420 

 

119 1% 100%

Jasper, IN 

 

30,043 33,531 11.6%

 

560 

 

60 0% 100%

Source: U.S. Census Bureau population estimates for 2000 and 2010 

Table 6. 2011 VMT for the Chicago Area. 

 2011 VMT % of Area Cum. % 

County Total 

Cook, IL 

 

31,705,270,056 45% 45% 

DuPage, IL 

 

8,059,051,190 11% 57% 

Will, IL 

 

5,518,889,913 8% 64% 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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 2011 VMT % of Area Cum. % 

County Total 

Lake, IL 

 

5,436,289,715 8% 72% 

Lake, IN 

 

4,664,891,193 7% 79% 

Kane, IL 

 

3,547,189,906 5% 84% 

McHenry, IL 

 

2,106,689,997 3% 87% 

Porter, IN 

 

1,836,723,893 3% 89% 

La Porte, IN 

 

1,702,002,112 2% 92% 

La Salle, IL 

 

1,333,020,018 2% 94% 

Kenosha, WI 

 

1,313,367,247 2% 96% 

Kankakee, IL 

 

969,019,995 1% 97% 

Kendall, IL 

 

768,299,498 1% 98% 

Jasper, IN 

 

710,369,578 1% 99% 

Grundy, IL 

 

693,739,990 1% 100% 

 

70,364,814,301 

Factor 3: Meteorology 

The EPA evaluated available meteorological data to determine how meteorological 

conditions, including, but not limited to, weather, transport patterns, and stagnation 

conditions, could affect the fate and transport of directly emitted particulate matter and 

precursor emissions from sources in the area of analysis. The EPA used two primary 

tools for this assessment: wind roses and kernel density estimation (KDE). When 

considered in combination with area PM2.5 composition and county-level and facility 

emissions source location information, wind roses and KDE can help to identify nearby 

areas contributing to violations at violating monitoring sites. 

Wind roses are graphic illustrations of the frequency of wind direction and wind speed. 

Wind direction can indicate the direction from which contributing emissions are 

transported; wind speed can indicate the force of the wind and thus the distance from 

which those emissions are transported. The EPA constructed wind roses from hourly 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 48 of 68

observations of wind direction and wind speed using 2009-2012 data from National 

Weather Service locations archived at the National Climate Data Center.6

 When 

developing these wind roses, the EPA also used wind observations collected at 

meteorological sampling stations collocated at air quality monitoring sites, where these 

data were available. Figure 1 shows wind roses that the EPA generated from data relevant 

in the Chicago area. 

As shown in Figure 1, while winds from the west and south are somewhat more frequent 

than winds from other directions, all directions have sufficient frequency of winds that 

emissions in all directions may be considered to contribute to violations at the violating 

monitor. 

                                                            

6 ftp.ncdc.noaa.gov/pub/data/noaa or 

http://gis.ncdc.noaa.gov/map/viewer/#app=cdo&cfg=cdo&theme=hourly&layers=1&node=gis Quality 

assurance of the National Weather Service data is described here: 

http://www1.ncdc.noaa.gov/pub/data/inventories/ish-qc.pdf 

Figure 1. Wind Roses in the Chicago Area
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 49 of 68

Factor 4: Geography/topography 

To evaluate the geography/topography factor, the EPA assessed physical features of the 

area of analysis that might define the airshed and thus affect the formation and 

distribution of PM2.5 concentrations over the area. The Chicago area does not have any 

geographical or topographical barriers significantly limiting air pollution transport within 

its airshed. Therefore, this factor did not play a significant role in this evaluation. 

Factor 5: Jurisdictional boundaries 

In defining the boundaries of the intended Chicago nonattainment area, the EPA 

considered existing jurisdictional boundaries, which can provide easily identifiable and 

recognized boundaries for purposes of implementing the NAAQS. Existing jurisdictional 

boundaries often signify well recognized boundaries that the state can easily administer 

and for which the state has the necessary legal authority for carrying out air quality 

planning and enforcement functions. Examples of such jurisdictional boundaries include 

existing/prior nonattainment area boundaries for particulate matter, county lines, air 

district boundaries, township boundaries, areas covered by a metropolitan planning 

organization, state lines, and Reservation boundaries, if applicable. Where existing 

jurisdictional boundaries were not adequate or appropriate to describe the nonattainment 

area, the EPA considered other clearly defined and permanent landmarks or geographic 

coordinates for purposes of identifying the boundaries of the intended designated areas. 

The Chicago area was previously designated nonattainment for the 1997 annual PM2.5

NAAQS. The EPA’s intended nonattainment area for the 2012 NAAQS is identical to 

area that was designated nonattainment for the 1997 NAAQS. Furthermore, the Illinois 

portion of the EPA’s intended nonattainment area matches the identical Illinois 

recommendations with respect to both the 2012 NAAQS and the 1997 NAAQS. On the 

other hand, the area within Indiana that the EPA designated nonattainment for the 1997 

standard exceeded Indiana’s recommendation for that standard (by including Porter 

County in addition to Lake County) and differs by two counties from Indiana’s 

recommendation that the nonattainment area for the 2012 NAAQS include no area within 

Indiana. 

Recent Chicago nonattainment areas for PM2.5 and for ozone have included the two 

townships in Grundy County and the one township in Kendall County that are included in 

the EPA’s intended 2012 PM2.5 NAAQS nonattainment area. Townships are well 

established and well recognized jurisdictional boundaries in Illinois, and so the use of 

these county subdivisions as boundaries for the nonattainment should provide for suitable 

ease of administration of nonattainment area requirements. These townships reflect the 

more urbanized portions of these otherwise relatively rural counties, and inclusion of 

these townships is consistent with Illinois’ recommendations and provides for a definition 

of the nonattainment area that is consistent with other nonattainment area boundaries for 

other NAAQS. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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This information demonstrates that a review of the most recent available information on 

the five factors identified in the 2013 guidance in accordance with that guidance supports 

defining the Chicago area as having the same boundaries as the EPA established in 2005. 

Comment: We believe that while the EPA and Illinois the EPA (IEPA) work to 

determine the cause and extent of any invalid PM2.5 data and appropriate remedies, there 

is sufficient technical evidence to support the exclusion of Grundy County townships 

from the Chicago PM2.5 nonattainment area. We ask that as you move forward with IEPA 

to clarify Illinois nonattainment boundaries, you exclude portions of Grundy County 

(specifically the townships of Aux Sable and Goose Lake) from consideration as part of 

the nonattainment area. Inclusion of counties that do not materially contribute to 

nonattainment can have severe negative economic consequences for that county. In 

addition to the potential of costly new regulations that do not improve air quality at the 

violating monitor, employers and manufacturers evaluating areas consider an area's 

attainment/non-attainment classification before making decisions on expansions or new 

facilities. 

In the case of Grundy County, IEPA's recommendation appears to have weighted 

meteorology, specifically prevailing wind direction, over all other factors. IEPA and the 

EPA should now reexamine the data, weight monitored air quality data and emissionsrelated data more appropriately, and remove Grundy County from any further 

nonattainment classification discussion. 

While the EPA has declared much if not all of IEPA's PM2.5 data invalid for technical 

reasons having to do with data collection and processing, this does not necessarily mean 

that the data is wholly inaccurate. IEPA's data tracks regional levels and trends observed 

by the CASTNET monitors in Illinois. For this reason, we believe that our earlier data 

analysis provided to IEPA in November 2013 is still appropriate to consider. 

Due to its small population, limited urban area, and moderate point source emissions 

potential, Grundy County is not required to have a PM2.5 monitor located in the county. 

However, adjacent Will County, which is downwind of Grundy County particularly on 

days when the violating Chicago monitor experienced higher PM2.5 levels, has two 

monitors. The annual average levels experienced by these monitors can be used to 

understand whether high PM2.5 levels are being emitted in Grundy County and making 

their way through transport to the violating monitor. The Joliet monitor in Will County 

downwind of Grundy County shows an annual average concentration of 11 μg/m3

, which 

is below the new 12 μg/m3

 NAAQS level. The Braidwood monitor, located immediately 

adjacent to Grundy County, shows an annual average concentration of 9.9 μg/m3. It 

should be noted that the Joliet monitor in Will County is located in close proximity to a 

large electric generating unit, or EGU, which is much more likely to contribute to the 

annual average concentration at this monitor rather than the much smaller, more distant 

emissions from Grundy County. Both the Joliet and Braidwood monitors have shown 

improved air quality in recent years. In the three-year period ending in 2009, the last 

period that the Joliet monitor exceeded the new NAAQS, its annual average was 12 

μg/m3

. It has continued to show declining PM2.5 concentrations, and as mentioned above, 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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most recently measured 11 μg/m3. The Braidwood monitor last exceeded the NAAQS in 

the 3-year period ending in 2004. PM2.5 concentrations have also decreased at this 

monitor, from 10.4 μg/m3 in the three-year period ending in 2009 to 9.9 μg/m3 in the 

most recent 3-year period. This analysis demonstrates suggests that the air flowing from 

Grundy County towards the Chicago region has some of the lowest PM2.5 concentrations 

in the region. Furthermore, trends in PM2.5 levels at these two closest monitors to Grundy 

County show decreasing amounts of PM2.5 levels, which supports this assertion. 

Additionally, predicted concentrations of PM2.5 for a portion of Grundy County, and 

several adjacent counties, represent some of the predicted lowest PM2.5 concentration in 

the Midwest. 

IEPA staff have over-relied on one factor—wind direction—in the five factor analysis. 

The exceedance concentrations experienced by one monitor in the Chicago region do not 

have a significant contribution from emissions in a county like Grundy that is predicted to 

experience low PM2.5 levels based on regional air quality monitors. Rather, they are much 

more likely to be emitted closer to the source of the sole exceeding monitor. 

From the available air quality data, then, it does not appear that emissions from Grundy 

County, as they may make their way toward the violating monitor, contribute in any 

material way to high PM2.5 levels at their closest monitors. We recognize that a recent 

technical systems audit of IEPA's monitoring program has invalidated much if not all of 

their recent PM2.5 monitoring data. However, Illinois also has Clean Air Status and 

Trends Network (CASTNET) monitors in Bondville (located near Champaign) and in 

Stockton (west of Chicago) which have independent analysis procedures, and which have 

not been invalidated. The Clean Air Status and Trends Network (CASTNET) is a national 

air quality monitoring network designed to provide data to assess trends in air quality, 

atmospheric deposition, and ecological effects due to changes in air pollutant emissions. 

CASTNET provides long-term monitoring of air quality in rural areas to determine trends 

in regional atmospheric nitrogen, sulfur, and ozone concentrations and deposition fluxes 

of sulfur and nitrogen pollutants in order to evaluate the effectiveness of national and 

regional air pollution control programs. A review of national CASTNET data indicates 

that significant reductions in SO2, SO4, HNO3, total NO3, and NH4 have been realized in 

the Eastern US. For example, between 1990-1992 and 2010-2012, SO2 concentrations 

were reduced from 8.9 μg/m3 to 2.1 μg/m3

, a 76% reduction. Therefore, we believe that 

an analysis of CASTNET recent measurements and trends lends independent support to 

the IEPA data showing low predicted PM2.5 emissions and precursors in rural areas such 

as Grundy County. Both Illinois CASTNET monitors demonstrate an observed 

downward trend (air quality improvement) in combined quarterly sulfate and nitrate from 

2001 through 2013. This trend is consistent with average and maximum annual and 24-hr 

PM2.5 concentration trends seen in other monitoring networks. Emissions of PM2.5 and its 

precursors and constituents from Grundy County represents the lowest category of 

emissions of any of the counties being considered for inclusion in the nonattainment area. 

In addition, according to 2011 NEI data, consistent with measured trends in constituent, 

precursor and PM2.5 concentrations, emissions of key constituent and precursors of PM2.5, 

as well as direct emissions of PM2.5 are lower in 2011 than in 2008, in some cases 

dramatically so. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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Emissions from key constituents, precursors and direct PM2.5 have decreased 

significantly. A slight increase in SO2 emissions is insignificant in the context of the total 

overall tons per year decrease demonstrated by the other emissions categories and in 

context of the overall SO2 emissions inventory for the proposed non-attainment area 

(Grundy County's SO2 emissions account for approximately 0.08% of the nine-county 

total SO2 emissions of 63,110.10 tpy). Furthermore, as IEPA notes in its designation 

recommendation, Grundy County contributes only 1.7% to the total emissions in the 

nine-county regions’ PM2.5 total. This updated information further supports our 

conclusion that emissions from Grundy County are an extremely small fraction of the 

total emissions in the proposed nonattainment area. The significant decreases in these 

emissions from 2008 to 2011 further supports this conclusion. 

In light of the decreasing emissions from 2008 to 2011, we contend the IEPA’s analyses 

of emission related factors do not support inclusion of Grundy County townships in a 

Chicago PM2.5 nonattainment area. Emissions-related factors are intended to place 

context around the emissions data, such as whether an emissions category is expected to 

grow in the future. A strong pattern of growth in population, vehicle miles traveled, 

industrial expansion, or nonroad transit might bolster an argument that a county with 

relatively insignificant current emissions should be included in a nonattainment area. In 

the case of Grundy County, analysis of emission-related factors do not make this case. 

IEPA’s analysis first discusses population density. In the case of Grundy County, the 

2010 population density was 119 people per square mile. In Cook County, the county 

with the sole violating monitor, the population density is 5,491 persons per square mile. 

The 50,063 residents of Grundy County make up 0.05% of the region's total population, 

the smallest fraction of any county being considered for inclusion in the nonattainment 

area. By 2012, the Grundy County population density increased by one person per square 

mile. By contrast, Cook County added 39 people per square mile. 

The document then provides population growth projections between 2000 and 2030. 

While Grundy County is predicted to add between 10,000-50,000 persons over that time 

period, four other counties in the region are predicted to add over 200,000 persons each. 

Clearly population growth in the region will not be driven by projected new inhabitants 

of Grundy County. 

The document then turns to VMT per county, and further breaks out the VMT for Aux 

Sable and Goose Lake townships. The combined VMT for those two townships 

represents 0.56% of that of Cook County, the county with the sole violating monitor. This 

comparison does not even include the VMT from the other counties being considered for 

inclusion in the region. Again, Grundy County has the smallest VMT of any county in the 

proposed nonattainment area. Grundy County does have a moderate percentage of its 

residents commuting out of the county for work. However, when one is dealing with the 

commuting habits of a county with 50,063 total inhabitants, the impact of their commute 

is dwarfed by the emissions and VMT of inhabitants of far more populous counties, such 

as Cook County, which has over 5 million residents. Therefore, the relative weight one 

gives to commuting patterns for Grundy County, especially as emissions from motor 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 53 of 68

vehicles continues to decline as a result of federal fuel and engine standards, should be 

extremely small. 

Wind roses and summary back trajectory data presented in the IEPA document show that 

on high PM2.5 days, winds most frequently originate in the South, South/South West, and 

South West sectors, which comprise Cook, Kankakee, Will and Grundy Counties. 

Interestingly, on the two days when the highest PM2.5 concentrations were experienced at 

the violating monitor, daily back trajectories demonstrate that wind directions were not 

from this sector. IEPA makes a case that winds were from a sector that includes Grundy 

County townships during several high PM2.5 days. However, it appears to weight that 

evidence far more strongly than it does the more compelling ambient air quality data and 

emissions and emissions related data. On some high PM2.5days, air parcels travel through 

Grundy County, and then through Will County and Cook County to reach the sole 

violating monitor some 50 miles downwind. But all available evidence suggests that the 

air that is being transported from Grundy County on those days does not contain a 

significant amount of PM2.5, its constituents or precursors. Therefore, meteorology, when 

viewed in the appropriate context with ambient air data and emissions data, should not be 

given the pre-eminent weight that it apparently has been given in this analysis. 

Geography and topography are not expected to be key drivers in the nonattainment 

boundary designation analysis. 

Grundy County is not contained in the Chicago Metropolitan Agency for Planning 

(CMAP). This organization is responsible for regional planning, including transportation 

and environmental planning. It is the designated Metropolitan Planning Organization 

(MPO) for the region, and is responsible for transportation planning to achieve 

transportation conformity with the State Implementation Plan. Grundy County's lack of 

inclusion in the organization charged with transportation, environmental planning, and 

the transportation conformity analysis creates a jurisdictional incompatibility that both 

highlights its lack of contribution of significant motor vehicle emissions to the region's 

total, and its inability to participate in future transportation planning decisions in the 

region. 

EPA Response: The EPA is designating the Chicago area as unclassifiable, not as 

nonattainment. Consequently, this designation will not create the “potential of costly new 

regulations” that the commenter fears, and the EPA presumes that a designation as 

unclassifiable does not significantly alter “decisions on expansions or new facilities” as 

compared to designation as attainment/unclassifiable. In any case, the EPA is presently 

obliged to determine boundaries of the Chicago area, an area that may or may not be 

violating the PM2.5 standard, but if subsequent data show the existence of violations of 

the standard, the EPA will conduct a new review of the area that contributes to the 

violations that will not necessarily be the same as the area the EPA currently believes to 

represent the Chicago area. For that matter, the EPA is designating the entire State of 

Illinois as unclassifiable, so the EPA believes that Grundy County should be designated 

unclassifiable regardless of whether portions of the county are or are not judged to be part 

of the Chicago unclassifiable area. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 54 of 68

The commenter provides substantial useful information for evaluating the potential of 

Grundy County to contribute to violations of the PM2.5 standard in the Chicago area. 

However, the EPA continues to believe that the relevant two townships in the county 

(Aux Sable and Goose Lake Townships) warrant being included in the Chicago 

unclassifiable area. Given the regional nature of PM2.5 concentrations, the air quality in 

Grundy County and neighboring Will and Kankakee Counties is not a good indicator of 

the potential of emissions elsewhere in the Chicago area where violations are more likely 

occurring. The commenter acknowledges that winds are prone to carry emissions from 

Grundy County into Cook County and elsewhere in the Chicago area where the potential 

for violations of the PM2.5 standard are greater, but the commenter argues that emissions 

in Grundy County are too low relative to emissions in other nearby counties to warrant 

including Grundy County as a contributing part of the Chicago area. The EPA 

acknowledges that the contributions of other nearby counties to potential violations in the 

Chicago area are likely to be greater than that of Grundy County, but the EPA believes 

that Grundy County has the potential for a sufficient impact on concentrations elsewhere 

in the area to warrant being designated as a contributing part of the Chicago 

unclassifiable area. The fact that Grundy County is not part of the Chicago Metropolitan 

Agency for Planning does not warrant excluding Grundy County as a contributing portion 

of the Chicago area. Nevertheless, as noted above, if the Chicago area is subsequently 

determined to be violating the PM2.5 standard, the EPA and Illinois will reassess the 

appropriate boundaries of the area, including reassessing whether Grundy County should 

be designated as part of the area. 

Comment: Indiana Department of Environmental Management (IDEM) believes that the 

certified, attaining 2011-2013 data collected by monitoring sites in Indiana’s monitoring 

network within Lake and Porter Counties, IN, should be sufficient to designate Lake and 

Porter Counties as “attainment” versus the intended “unclassifiable” designation 

associated with the Chicago, IL area (including Lake and Porter Counties, IN) as 

indicated in the EPA’s August 19, 2014 letter. 

EPA Response: The EPA believes that areas designated as unclassifiable must include all 

locations that are contributing to concentrations that may be above the standard. The 

Chicago area may be violating the standard, and Lake and Porter Counties have sufficient 

emissions that are transported to relevant portions of the Chicago area with sufficient 

frequency to warrant designating these two counties as contributing to potential 

violations. That is, the EPA is designating a Chicago unclassifiable area that includes 

both those portions of the area that may or may not be violating the standard and those 

portions of the area (including Lake and Porter Counties) that would reasonably be 

expected to be contributing to a violation if in fact a violation is occurring. 

3.2.4. EPA Region VI 

Comment: Sierra Club states that for the reasons outlined in their comment letter, 

including the allegedly capricious nature of the 2011-2013 time period for the design 

value, the problems with the state’s exceptional events requests, and the community 

based monitoring showing nonattainment levels of PM2.5 in certain Houston 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 55 of 68

communities, the commenters respectfully oppose the designation of Houston as 

attainment and recommend a designation of nonattainment. Sierra Club states that the 

levels of PM2.5 in the Houston area during the 2010-2012 three year period, and the dates 

evaluated by the State of Texas for its November 26, 2013 recommendation letter to the 

EPA, indicate that people in Houston are breathing unhealthy air. Despite the State’s 

evaluation of air quality and exceptional events issues during 2010-2012, and Sierra 

Club’s participation in that process and in particular the issue of exceptional events, 

Sierra Club asserts the EPA has inappropriately proposed to change the basis for the 

decision to the 2011-2013 three year period. Sierra Club states the selection of another 

three year period different than the one that the State of Texas evaluated for its 

recommendation follows a recent pattern by the EPA, and that the allegedly capricious 

nature of these kinds of changes is inappropriate and leads to poor policy. Sierra Club 

explains the Clean Air Act describes a particular process for designation decisions and 

the EPA should not deviate from that process in a capricious manner by selecting time 

periods to avoid nonattainment designations, and thus minimize its own workload or the 

workload of the states. Sierra Club states the nonattainment SIP process can bring 

important public health benefits in cities with poor air quality and avoiding workload or 

political pushback are poor reasons for selecting time periods for evaluation. Sierra Club 

contends the EPA should not shift this time period, or in the alternative, should allow 

another period of notice and comment to allow the public and the State to evaluate this 

new time period. 

EPA Response: The EPA disagrees with the Sierra Club statement that using data from 

2011 to 2013 is capricious in nature, is inappropriate and leads to poor policy. As stated 

on page 3 of the EPA’s April 16, 2013 Memorandum from Gina McCarthy to Regional 

Administrators: “We expect that in providing designations recommendations to the EPA 

by December 13, 2013, states and tribes will also review air quality data from 2010 to 

2012. However, prior to EPA making final designations decisions, quality-assured, 

certified air quality monitoring data from 2013 may be available. If so, EPA’s final 

designations decisions will be based on data from 2011 to 2013.” This guidance memo 

was shared with the states and tribal governments and other stakeholders and made 

available to the public. The EPA has followed this policy of relying on the most recently 

available certified data in numerous initial area designations for multiple NAAQS, 

including most recently the area designations for the 2008 ozone NAAQS. The EPA 

believes that it is important to base area designation decisions on the most recently 

available certified monitoring data specifically for pollutants, such as PM2.5, where the 

emissions inventories are trending upward or downward, signaling the potential for 3-

year design values to shift above or below the level of the NAAQS. In the case of the 

Houston area, the emissions of the precursor pollutants oxides of nitrogen and sulfur 

dioxide are declining, and we see these emissions trends reflected in the monitored 

ambient concentrations.

Comment: The commenters provided an extensive set of concerns about the TCEQ’s use 

of exceptional events data exclusion requests. 

 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 56 of 68

EPA Response: The EPA based its intended and final area designation for the Houston 

area on certified and quality-assured monitoring data for the period from 2011 to 2013. 

The 3-year design value on which we based our decision was calculated without 

excluding dates flagged as exceptional events. Therefore, the comment is moot. 

Comment: The commenters questioned whether the monitoring data obtained at the 

Clinton Drive Monitor site is representative for the Galena Park community and 

submitted monitoring data gathered from five monitoring sites operated by Air Alliance 

Houston at various locations within the community (see Figure 2 below). The 

commenters believe the Air Alliance monitoring data demonstrated that the Clinton Drive 

monitor was not representative of area air quality and that the area could be in violation 

of the NAAQS. 

EPA Response: We first note that we must consider all valid data within the relevant 3-

year time frame that is collected in conformance with the Federal Reference Methods and 

siting requirements in our designation decision. As discussed below, the Clinton Drive 

monitoring site meets these requirements and therefore, must be considered. The location 

of the Clinton Drive monitor conforms to all applicable siting criteria, as set forth in 40 

CFR Part 58, Appendix D and E, and has been approved by the EPA as part of TCEQ’s 

most recent Annual Monitoring Network Plan and 5-year Monitoring Network 

Assessment. The Clinton Drive monitor is approximately 1.5 miles from Galena Park, as 

shown in Figure 2. At Clinton Drive, TCEQ operates PM2.5 Federal Reference Method 

(FRM) and non-FRM continuous monitors. 

Figure 2. Clinton Drive and Galena Park Community Monitoring Sites 

Note: Clinton Drive Monitor (Location A), and Galena Park Monitors (Locations B – F). 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 57 of 68

With regard to whether the data collected by Air Alliance Houston indicates a violation, 

Region 6 evaluated the monitoring data submitted by the commenter. Approximately 29 

discrete samples were collected in the Galena Park community over a 16-month period 

from May 2012 through September 2013, thus the data is limited in scope compared to 

the data collected by regulatory monitors over a 3-year period and subject to data 

completion criteria. Additionally, these data were also not monitored and collected 

according to the requirements of the federal reference method for PM2.5 found in 40 CFR 

part 50, Appendix L. Our designations must be based on valid 3-year design values, and 

even if the monitoring data submitted by the commenters fully complied with the siting 

and data quality criteria, there are not sufficient data on which to derive a valid, 3-year 

design value. 

Therefore, these data do not affect our decision to designate the area as Unclassifiable/ 

Attainment. 

3.2.5. EPA Region IX 

Comment: Nevada Bureau of Air Quality Planning has received the EPA’s August 19, 

2014, letter indicating the intended designation of unclassifiable/attainment for the entire 

state of Nevada. Nevada agrees with this intended designation and requests that final 

designations subdivide the state according to hydrographic areas. 

 

EPA Response: The EPA appreciates the commenters’ support and is designating areas 

in Nevada based on hydrographic areas. 

Comment: The California Air Resources Board (CARB) appreciates the time, effort, and 

collaborative approach U.S. EPA staff took to identify the proposed nonattainment areas 

as well as surrounding areas that may contribute to the high measured values. CARB also 

notes that the extensive analysis contained in the preliminary Technical Support 

Document matches CARB’s recommendations for PM2.5 nonattainment areas in the State 

and appropriately captures the areas of high measured PM2.5 and the surrounding areas 

from which emissions can contribute to the high measured levels. CARB looks forward 

to continued collaboration with U.S. EPA in protecting public health for all Californians.

EPA Response: The EPA appreciates the commenters’ support.

Comment: The Pechanga Band of Luiseño Mission Indians submits a revised 

recommendation of “unclassifiable/attainment” based on complete, certified 2011-2013 

monitoring data that indicate that areas of Indian country are attaining the 2012 annual 

PM2.5 standard. The Tribe also requests consultation regarding final designations. 

EPA Response: The EPA appreciates the updated and revised recommendation from the 

Pechanga tribe. The EPA’s preliminary review of monitoring data agrees with the Tribe’s 

conclusions and the EPA agrees with the Tribe’s revised recommendation to designate 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

Page 58 of 68

their portion of Indian country as “unclassifiable/attainment” for the 2012 annual PM2.5

standard.

Comment: The Soboba Band of Luiseño Indians requests consultation to address 

questions related to the technical analyses included in the preliminary California 

Technical Support Document that support inclusion of the Soboba Indian Reservation in 

the Los Angeles-South Coast Air Basin nonattainment area for the 2012 annual PM2.5

standard. 

EPA Response: The EPA welcomes the Soboba tribe’s request for consultation and has 

initiated consultation with the tribe. 

3.2.6. EPA Region X 

Comment: The December 6, 2013, state recommendation letter from Idaho Department 

of Environmental Quality (IDEQ) to the EPA Region 10 showed that according to the 

2012 standards, the Pinehurst monitor had not exceeded the standard. In August 2014, the 

EPA Region Administrator Dennis McLerran sent a letter to Governor Otter stating that 

the EPA is proceeding with intended initial area designations using quality-assured, 

certified air quality monitoring data from 2011-2013. The letter from the EPA further 

stated that after “extensive collaborative discussions with IDEQ, and consideration of 

other relevant technical information, including 2011-2013 air quality data and 2014 

technical analyses, the EPA intends to designate a partial area of Shoshone County 

(limited to areas surrounding the towns of Pinehurst, Smelterville, and Kellogg) as nonattainment.” 

The commenter believes that this letter defied the Governor and IDEQ’s 

recommendations, did not specifically state what was collaborated upon, and used a 2014 

technical analysis which has either not been finalized or is not available to the public. 

EPA Response: The EPA and IDEQ have worked together to review the data and 

develop the technical analyses in the West Silver Valley (WSV) Technical Support 

Document (TSD). The EPA’s final 2012 Annual PM2.5 NAAQS revision provided that, 

pursuant to section 107(d)(1) of the CAA, states were to submit initial designation 

recommendations by December 13, 2013 (78 FR 3086, 3250 Jan. 15, 2013). Such a 

designation recommendation would necessarily be based on air quality data from 2010-

2012 because data for 2013 was not yet be available. The final rule also acknowledged, 

however, that if data from 2013 became available before the EPA finalized the area 

designations, the EPA’s designation decision would be based on air quality data from 

2011-2013, which are the most recent three consecutive years of data (78 FR 3259-51), 

The WSV TSD was available to the public for review in its draft form, and was part of 

the rulemaking docket for the proposed area designations for the 2012 PM2.5 Annual 

NAAQS. The TSD was finalized after consideration of comments received during the 

public process provided for the area designation. The purpose of proposing a draft 
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document as opposed to a final document was to provide an open and transparent process 

that allowed for meaningful input from both the state and the public at large. 

Comment: The commenter states that pages 7, 29, and 31 of the Idaho TSD state include 

the design values based on 2010‐2012 data, and that the figures will be updated in the 

final TSD with 2011‐2013 data. The commenter believes that this will deprive the state 

and public from being able to adequately comment without a final document. 

The commenter states that the technical analysis gives the West Silver Valley a 12.8 

μg/m3 design value after excluding only 4 days of exemptions due to exceptional events, 

and that while additional exceptional event days may exist, exclusion of those days could 

not lower the design value enough to amount to meet the standard. The commenter states 

that the EPA has left out 31 days that were requested by the IDEQ and that this could 

bring the design value down to 12.0 μg/m3. 

The commenter further states that the technical analysis includes data from surrounding 

non-regulatory monitors and areas outside of the Area of Concern, while only one other 

monitor is listed as being in the Area of Concern. The commenter states that charts in the 

TSD are complicated and difficult to read due to font-size and color choice. Finally, the 

commenter states that the analysis omits reference to any established or estimated PM2.5

concentrations on either a mean or seasonal basis, or to short-term peak background 

levels PM2.5, and points to a 2006 study in British Columbia, Canada, which the 

commenter is noteworthy for assessing true PM concentrations. 

EPA Response: The figures referred to on pages 7, 29, and 31 were generated using a 

mapping tool that used the 2010-2012 design value as opposed to the 2011-2013 DV 

data. However, this did not affect the content and purpose of the figures in the TSD as 

they were used to for the purpose of depicting the area of analysis, population, and 

vehicle miles traveled respectively and did not reference or use the design value in the 

figures. The data underlying these figures did not change in the final TSD and several 

disclaimers were for maps generated using the tool that incorporated the 2010-2012 

design value. As noted above, because the inclusion of these figures in the TSD was for 

informational purposes unrelated to the design value, the ability for the public to 

comment on the figures was unaffected by the mapping tool’s reference the 2010-2012 

design value. 

The design value has been correctly calculated and Table 2a on page 10 of the Idaho TSD 

provides this information. The IDEQ submitted to the EPA four exceptional event days at 

the Pinehurst, Idaho monitor for concurrence. The EPA has concurred on all four of these 

submitted days and the resulting final 2011-2013 design value for the Pinehurst, ID 

monitor is 12.8 μg/m3

. The IDEQ has indicated that there are additional days that may 

potentially qualify as exceptional events days. However, both the EPA and IDEQ have 

independently confirmed that even if these additional potential exceptional events days 

were approved and their values were removed for purposes of calculating the design 

value, the monitor’s design value for 2011-2013 would still be above the 12.0 μg/m3

standard. Information supporting this conclusion may be found in the docket. The IDEQ 
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has indicated that it may submit additional exceptional event days for the EPA 

concurrence in the future. 

The use of multiple monitors within the area of analysis, regulatory and non-regulatory, 

allows for a more detailed understanding of potential contributors to the violation 

registered at the Pinehurst monitor for 2011-2013. Detailed graphs and emissions 

inventories are important for understanding emissions sources in the nonattainment area. 

Unfortunately, this can cause difficulty with the color keys and overall complexity even 

though we attempt to make the documentation as readable as possible. In the document 

background emissions are discussed and considered through the urban increment, and 

seasonal and monthly emissions trends are essential to understand when emissions are 

affecting the monitor. The 2006 British Columbia cited by this commenter does not 

provide additional relevant information justifying a departure from the EPA’s method of 

analysis for this annual PM2.5 standard. 

Comment: The commenter notes that the EPA’s technical analysis for Illinois is just 8 

pages, and does not agree with the Illinois Environmental Protection Agency’s 

recommendation. The commenter states that the EPA has used its discretion in the area 

designation process, and that the West Silver Valley has been unfairly treated. 

The commenter states that the EPA has identified that Residential Wood Stoves are the 

reason for non-attainment in the West Silver Valley. The commenter inquires about the 

contribution from fireplaces and identifies that fireplaces are not being considered in the 

upcoming regulations on strengthening the standards on “residential wood heaters”. 

The commenter states that most homes the WSV use fireplaces with inserts, and 

insinuates that the attainment plan is to replace wood heaters with new devices through a 

loan & tax credits. The commenter cites that they will be out of the EPA compliance in 5-

7 years, and that many wood heat manufacturers may not be able to meet the 

requirements. http://www.newsmax.com/Newsfront/epa-woodstoveban/2014/02/23/id/554234/ 

EPA Response: The EPA strives to maintain a nationally consistent process for 

designating areas when there is a new or revised air quality standard. The area 

designations require three consecutive years of certified air quality monitoring data. The 

technical analysis for Illinois was for a designation of “unclassifiable,” due to pervasive 

problems affecting monitoring data in the entire state. These pervasive data problems 

prevented the EPA from being able to determine whether Illinois (and parts of adjacent 

states) met the NAAQS. Further details can be found elsewhere in this Response to 

Comments document. The same deficiencies were not present with respect to Idaho. 

The WSV TSD identifies residential wood combustion as a leading contributor to 

exceedances of the standard. Residential wood heating encompasses a wide variety of 

home heating sources including, but not limited to woodstoves and fireplaces. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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A common misconception is that the designations process addresses control strategies. 

For proposed nonattainment areas, this action only identifies the areas violating the 

NAAQS, or contributing to such nearby violations. Once the nonattainment area 

designation becomes finalized, the state and/or local air quality agency will work with the 

affected community to identify strategies to reduce the emissions in the finalized 

nonattainment areas. This would be part of the attainment plan development. 

The EPA is only considering comments related to the proposed area designations for the 

2012 Annual PM2.5 NAAQS. The EPA accepted and is currently reviewing comments on 

the proposed NSPS for new woodstoves. This comment period is now closed. 

Information on this action can be found at the docket for Revised NSPS for new 

Residential Wood Heaters - EPA-HQ-OAR-2009-0734. 

Comment: The commenter states that the EPA’s views regarding the health impacts of 

wood heaters are based on only a handful of old, peer-reviewed studies. Furthermore, the 

commenter claims that none of these studies consider short-term human health impacts. 

The commenter states that the EPA does not use proper science, peer-reviewed studies, or 

cross-benefit analyses in the designations process. 

EPA Response: Significant research forms the basis for the national ambient air quality 

standards prior to promulgation. The multiyear process includes planning, integrated 

science assessment, risk/exposure assessment, and policy assessment. For the 2012 PM2.5

annual standard revision, the EPA initiated its review in June 2007. Between 2007 and 

2011, the EPA prepared draft and final Integrated Science Assessments, Risk and 

Exposure Assessments, and Policy Assessments. Multiple drafts of all of these 

documents were subject to review by the public and were peer reviewed by the EPA’s 

Clean Air Scientific Advisory Committee (CASAC). 

All NAAQS are set to protect public health and the environment for all populations 

nationwide. The 2012 PM2.5 standard was adopted in response to a court ruling that 

remanded the primary annual PM2.5 standard to the EPA finding the Agency had failed to 

explain adequately why the standard provided the requisite protection from both shortand long-term exposures to fine particles, including protection for at-risk populations 

such as children. The resulting 2012 PM2.5 annual NAAQS provides increased protection 

for children, older adults, persons with pre-existing heart and lung disease, and other atrisk populations against an array of PM2.5 related adverse health effects that include 

premature mortality, increased hospital admissions and emergency department visits, and 

development of chronic respiratory disease. 

All of the information generated from this process for the particulate matter standards is 

publicly available at http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html. 

Comment: The Idaho Department of Lands (IDL) concurs with many statements made by 

the EPA in the proposal, including with respect to topographical influences on PM2.5

concentrations in and around the Pinehurst area. However, IDL believes any increase in 
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December 17, 2014 

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the non-attainment boundary from the existing PM10 boundary should be supported by 

technical data from multiple monitors exceeding the NAAQS. 

The commenter prefers a boundary for the 2012 annual PM2.5 nonattainment area that is 

coterminous with the existing PM10 boundary, and that thus would include a smaller 

portion of Shoshone County. The commenter questions the appropriateness of the 

proposed WSV boundary, specifically to the North of Interstate 90, and believes that the 

proposed boundary lacked sufficient supporting technical information: 

“Pinehurst is in the center of a convergence zone of multiple large mountain drainages. 

The typical diurnal flow of air referenced in the EPA and DEQ studies do exist. One 

issue that Pinehurst has is a small pinch point on the North side of town where Interstate 

90 passes over Pine Creek. This point hence the city of Pinehurst, commonly becomes a 

stagnant air mass because of the larger influential drainage of the South Fork of the 

Coeur d'Alene which is the Interstate 90 corridor to the East. This stagnancy in 

combination with local valley inversions creates a bottle neck for air flow.

“The times of high accumulation of particulates fall within the months of December, 

January and February. These are the months which cause the area to exceed the annual 

PM2.5 standards. Focused community outreach during these periods of air stagnation 

would help to improve community education, support and reduce air quality degradation. 

There is insufficient technical data which supports the influence of PM2.5 contributors 

outside of the Pine Creek drainage. 

“The IDL believes it is reasonable to delay the implementation of the proposed boundary 

and increase monitoring for two years. This data would be able to provide the technical 

reference on making a more reliable decision on boundary placement. The standard 

changed in 2012, not the topography.” 

This commenter included data with their submission, including Wind Ninja modeling 

runs for diurnal flow, and wind roses for Pinehurst. The commenter concluded with a 

suggestion for: 

“...the addition of three temporary smoke particulate monitors, one in the South Fork of 

the Coeur d'Alene River drainage in Smelterville, one in Kingston to the West of 

Pinehurst and one at the confluence of the West/ East Fork of Pine Creek, South of 

Pinehurst. Data from these three additional locations would be able to clearly define what 

the main influences are, where they come from and what the focus should be for 

increasing the health standards for Pinehurst Idaho.” 

EPA Response: 

The EPA believes that the proposed nonattainment area boundary is appropriate based on 

a weight of evidence analysis that included multiple sophisticated modeling tools. The 

Wind Ninja modeling results submitted with this comment complement the suite of 

modeling results in this proposal, but do not contradict those results. It is important to 

point out that the area is in violation of an annual standard, so analyses are needed to 

address potential sources impacting the monitor throughout the full year rather than 
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focusing only on sources during the most impactful months for PM2.5. Regardless of the 

PM10 boundary, modeling results leading to the proposed (now finalized) nonattainment 

boundary showed that prescribed fires and slash fires were potential contributers to PM2.5 

at the violating monitor during the fall and spring seasons. These fires were within the 

current proposed nonattainment boundaries but beyond the more limited boundaries 

suggested in this comment. 

As identified in the WSV TSD, the area has been analyzed using a five factor analysis. 

This includes review of air quality data from the Pinehurst monitor as well as data from 

monitors in surrounding areas. The decision was also supported by emissions inventory 

information along with modeling across a multi-county domain in Northern Idaho. The 

weight of evidence from the various analyses identified that the majority of emissions 

affecting the area were generated within close proximity of the monitor during the 

wintertime. It also identified that during the shoulder seasons, fall and spring, there are 

emissions from prescribed and slash burning affecting the monitor. There is sufficient 

weight of evidence based on current monitoring data to support the nonattainment area at 

issue here, and to ensure that all emissions contributing to the monitor are within the 

nonattainment area. 

3.2.7. Multi-Region Areas 

3.2.7.1. Louisville, KY-IN 

Comment: The Kentucky Energy and Environment Cabinet (KEEC) comments that the 

EPA is inconsistent in applying and evaluating PM2.5 air quality in the Louisville, KY-IN 

Area. KEEC states that the EPA intends to use 2011-2013 data from a monitoring site in 

Indiana with a violating design value as the basis for a nonattainment designation for the 

2012 annual PM2.5 NAAQS, but has not acted on a pending redesignation request for the 

1997 annual PM2.5 NAAQS due to data quality issues with air quality monitors in 

Jefferson County, Kentucky. KEEC believes that if the EPA is willing to use the ambient 

air monitoring data from the Clark County, Indiana, monitor for the PM2.5 nonattainment 

designation for the 2012 standard, then the EPA should also use the data to finalize the 

attainment designation for the 1997 standard, particularly since the Clark County, 

Indiana, monitor has been the design value monitor for the Louisville KY-IN Area since 

2007. 

EPA Response: The EPA must consider the monitoring data from all monitors in an area 

in making a designation decision. While it only takes one monitor in an area to indicate 

that an area is violating a standard, it takes all of the monitors in an area to provide 

assurance that an area is in compliance with that standard. The only complete, qualityassured data from the Louisville, KY-IN Area is from the Clark County, Indiana, monitor 

which shows a violation of the standard based on 2011-2013 data. Because data are not 

available for the monitors in Jefferson County, Kentucky, it is not apparent to the EPA 

that the Clark County, Indiana, monitor is the design value monitor for the Area or what 

the monitors in Jefferson County, Kentucky, would indicate if these monitors had 

complete, quality-assured data. The EPA notes that the highest reading monitor in the 

Area when the EPA finalized the Louisville, KY-IN Area designation for the 1997 PM2.5
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NAAQS in 2005 was in Jefferson County, Kentucky. For all of these reasons, the EPA is 

designating the Area as nonattainment. However, as the EPA has previously indicated, 

areas may opt to early certify monitoring data for the EPA’s consideration. In its response 

letter to the EPA, Indiana stated that the Clark County, Indiana, monitor is expected to 

show attainment at that monitor based on 2012-2014 data and that Indiana intends to 

early certify this data for the EPA’s consideration. The EPA agrees with Indiana. that in 

the event that the Clark County, Indiana, monitor has complete, quality-assured data that 

shows attainment for 2012-2014 at that monitor, it is appropriate for the EPA to designate 

the Louisville, KY-IN Area as unclassifiable because of the incomplete data in Jefferson 

County, Kentucky, for 2011, 2012, and 2013. Additionally, it is not anticipated that the 

monitors in Jefferson County, Kentucky will have complete data for the 2012-2014 time 

period. 

While the EPA’s evaluation of the redesignation request for the Louisville KY-IN Area 

for the 1997 PM2.5 standard is outside of the scope of the designation process for the 2012 

PM2.5 standards, the EPA notes that complete, quality-assured data for the entire area 

(i.e., monitors in Indiana and Kentucky) are required to support the redesignation. 

Comment: The Kentucky Energy and Environment Cabinet (KEEC) notes that the 

preliminary Technical Support Document for the Louisville, KY-IN Area that the EPA 

developed and included in its 120-day letter to Kentucky Governor Steven Beshear on 

August 19, 2014, relied upon emissions data from 2011 and 2012. KEEC notes that 

additional reductions in PM2.5, SO2, and NOx will occur in the Louisville KY-IN Area as 

a result of two emission reduction projects at the Louisville Gas & Electric’s (LG&E) 

Mill Creek and Cane Run facilities that are scheduled for completion by the end of 2016. 

KEEC asks that the EPA designate the Louisville KY-IN Area as 

unclassifiable/attainment based on the anticipated emissions reductions from these 

projects and on Indiana’s expected early certification of 2014 data. 

EPA Response: The EPA appreciates the information regarding the upcoming emissions 

reductions in PM2.5, SO2, and NOx at the LG&E’s Mill Creek and Cane Run facilities 

and is aware of Indiana’s belief that the Clark County, Indiana, monitor will show 

attainment of the PM2.5 NAAQS from 2012-2014 at that monitor once 2014 data is 

certified. For designations, the EPA must base its determination on the air quality data 

and emissions for the area at the time of the final designations. As discussed above, the 

EPA will consider the 2012-2014 data from this monitor if Indiana early certifies 

complete, quality-assured data for 2014. The Agency agrees with Indiana that in the 

event that the Clark County, Indiana, monitor has complete, quality-assured data showing 

attainment for 2012-2014 at that monitor, it is appropriate for the EPA to designate the 

Louisville, KY-IN Area as unclassifiable because of the incomplete data in Jefferson 

County, Kentucky for the time period of designations. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

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3.2.7.2. Cincinnati-Hamilton, OH-KY 

Comment: Ohio EPA (OEPA) commented that the intended boundary for the 

Cincinnati-Hamilton area should not include the intended partial Warren County. OEPA 

notes that the EPA’s analysis included demonstrating the percent of total pollutants that 

Warren county contributes compared to other counties in the intended nonattainment 

area, including VMT, but due to the fact that the wind direction is predominantly from 

the south/southwest, while Warren County is east/northeast of the violating monitors, the 

area is not contributing to the violation, or is a “weak contributor” and therefore should 

be designated attainment, rather than nonattainment based on contribution to the violating 

monitors. 

EPA Response: In fact, the wind roses shown in Figure 8 of the TSD indicate winds 

blowing from the northeast direction during a moderate fraction of the 2010-2012 3-year 

period. Additionally, the EPA’s KDE plots included in the TSD (Figure 9) show a high 

frequency (greater than 50% of the maximum frequency) of trajectories passing over grid 

cells that include the portions of Warren County that were included as the intended 

boundary. The EPA also notes that for the 2012 annual NAAQS, the monitor data for the 

entire calendar year (including on days that are below the level of the NAAQS) are part 

of the mathematical calculation of whether a monitor is nonattainment or not. Thus, 

contribution is still relevant even during a single season, during days that wind directions 

are coming from the east/northeast, or during periods that do not have high ambient 

levels. Accordingly, this was one of the factors used when including Warren County in 

the nonattainment area. 

The EPA also notes that during the multifactor analysis the EPA also considered Warren 

County’s contribution to direct PM from mobile sources moving into Hamilton County 

(the area with the violating monitors), and furthermore assessed contribution from the 

population and urban area of Warren County that is part of the continuous Cincinnatimetro area. The mobile sources in particular move into the area where the violations are 

being monitored, leading to direct contribution regardless of wind direction. While the 

commenter notes that only 5.2% of the area’s commuters are from Warren County, the 

number of VMT for 2011 in Warren County is over 2 billion miles, and it had the third 

highest VMT for the intended nonattainment area, as noted in the TSD sent to the state 

and posted as part of the FR notice. 

The commenter also notes that the area is a “weak contributor” as far as precursors due to 

wind direction and the lack of major point sources in the county; however, the statute is 

clear in providing for inclusion in nonattainment areas of areas that “contribute” to the 

violations. The EPA interprets the term “contributes” to mean contributes sufficiently to 

justify inclusion in the nonattainment area, and the EPA’s multifactor test with the 

various analytical tools is intended to assure an objective evaluation of the appropriate 

facts on a case by case basis in each area. The EPA has considered multiple factors of 

analysis, and has applied the same analysis to all counties considered in the area of 

analysis as outline in the TSD. The EPA’s decision is not contingent on only one part of 

the analysis, but the analysis as a whole especially given that PM is a complex pollutant 
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with contribution from multiple source categories as well as multiple pollutants. Hence, 

the EPA’s use of the weight of evidence approach evaluating the facts and circumstances 

in each area on a case by case basis, and was done consistently with decision principles to 

assure comparable treatment in all the designations. 

Comment: The Kentucky Energy and Environment Cabinet (KEEC) provided comments 

regarding the Kentucky portion of the intended Cincinnati-Hamilton nonattainment area, 

the partial counties of Boone, Kenton, and Campbell. KEEC comments that they believe 

the monitored violations are due to local sources only, and that monitors measuring 

attainment both upwind and downwind of the violating monitor’s shows that the 

violations are from local sources only. The comments point to local rail yards, rail lines, 

and highways as the sources that are causing the violation given their location to the 

violating monitors. The comments also cite the EPA’s TSD enclosed with the 120-day 

letters, noting that the Kentucky counties each account for less than 10% of the emissions 

for each pollutant or precursor within the area of analysis. 

EPA Response: The commenter has not provided emissions associated with these 

sources allegedly causing the violations, nor has the commenter provided any additional 

evidence that emissions from these sources would be the only contributors of PM 

monitored at the violating monitors. Very localized sources may contribute to the 

violation, along with other sources in the nonattainment area. As a general matter, single 

sources cause concentrations that are only a fraction of the standard, even in their 

immediate vicinity, and violations instead reflect the contributions of numerous sources 

throughout an urban area (in addition to significant “background concentrations” from 

more distant sources). To determine the contribution of nearby areas, the EPA provided a 

multiple factor analysis that looked at the various sources of PM in the area, their total 

emissions, as well as wind direction impacting the monitors, and the source of the air 

mass that cover the continuous nonattainment area through back trajectories (noted as 

KDEs in the TSD). The three counties (Boone, Kenton, and Campbell) in Kentucky were 

found to be commonly upwind of the violating monitor based on the wind roses and 

KDEs (see Figures 8 and 9 of the TSD), and to have emissions that the EPA considers 

contributing to the violation due to both magnitude – as measured in tons per year – as 

well as composition, with the VMT and population in the Kentucky areas contributing to 

higher upwind emissions. The EPA’s multifactor test with the various analytical tools is 

intended to assure an objective evaluation of the appropriate facts on a case by case basis 

in each area, and the EPA has determined through the weight-of- evidence presented in 

the TSD that the areas in Kentucky contribute to the violations in Hamilton County. 

Moreover, the fact that there are monitors showing attainment does not prove that there is 

no contribution from the area, since the nature of PM2.5 is that a group of sources that 

may not be causing a violation in one location may in combination with other nearby 

sources be contributing to violations elsewhere nearby. 

The commenter also notes that emissions from sources in each of the Kentucky areas are 

10% or less. The statute does not require the EPA to establish or use a bright line test or 

threshold (in this case an emissions percentage) to define what constitutes contribution. 

Indeed, the EPA has said that to do so would potentially result in arbitrary and capricious 

decisions in areas where such a test would make no sense by including or excluding areas 
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without regard to other more relevant information. Hence, the EPA’s use of the weight of 

evidence approach evaluating the facts and circumstances in each area on a case by case 

basis, but done consistently with decision principles to assure comparable treatment in all 

the designations. In this case the emissions from these counties’ sources, plus the 

meteorology, and the amount of VMT and population were all noted as part of the 

analysis the EPA conducted in the TSDs that resulted in the determination that these 

counties contribute to the violations in Hamilton County and should be included in the 

nonattainment area. 

3.2.7.3. St. Louis, MO-IL 

Comment: The Missouri Department of Natural Resources (MO DNR) reiterates their 

recommendation that the EPA designate all portions of Missouri, including those areas in 

the St. Louis area, as unclassifiable/attainment. MO DNR is concerned that if the EPA 

designates the City of St. Louis and St. Louis, St. Charles, Franklin, and Jefferson 

Counties as “unclassifiable” because of uncertainty with the Illinois monitoring data as 

indicated in the August 19, 2014 letter to Missouri Governor Nixon, then the 

unclassifiable designation may leave the St. Louis area open to a potential future 

nonattainment area designation when Illinois resolves its PM2.5 monitoring issues. MO 

DNR further states that an unclassifiable/attainment designation is appropriate regardless 

of the uncertainty of Illinois data because all monitors in Missouri attain the 2012 annual 

PM2.5 NAAQS and are trending downward. 

EPA Response: The EPA must consider the monitoring data from all monitors in an area 

to inform the appropriate designation decision. While it only takes one monitor in an area 

to indicate that an area is violating a standard, it takes all of the monitors in an area to 

provide assurance that an area is in compliance with that standard. In the case of St. Louis 

MO-IL, the monitoring data on the IL portion of the area is invalid, thus the EPA can’t 

verify if the area would be attaining. The IL monitors have historically been the design 

value monitors for the area so relying on attaining monitors in Missouri is not appropriate 

as these Missouri monitors have not historically had the highest design values in the area. 

The EPA is using “unclassifiable” for those areas where the EPA was not able to 

determine based on available information whether the area is meeting or not meeting the 

NAAQS or where the EPA was not able to determine that the area contributes to a nearby 

violation. In this case the EPA cannot determine if the area meets the NAAQS or 

determine if the MO area contributes to a nearby violation, thus the EPA is designating 

all portions of St. Louis Missouri as unclassifiable. 

Comment: MO DNR notes that it is inappropriate to include areas in Missouri in an ILMO unclassifiable area based on the TSD for the 1997 annual PM2.5 NAAQS because at 

the time that TSD was developed, monitors in Missouri were violating the 1997 standard 

of 15 μg/m3

 and the TSD analysis was based on assessing contribution to a violating 

Missouri monitor. 
Responses to Significant Comments 2012 Annual PM2.5 NAAQS 

December 17, 2014 

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EPA Response: The EPA is including areas in Missouri because of the uncertainty in 

both monitored values and potential contributions to possible violations of the NAAQS. 

Because the area has a history of nonattainment the EPA did review past analysis to help 

inform the unclassifiable boundary determination. The EPA does not believe it is 

inappropriate to consider past analyses to help inform this decision. The EPA also 

believes that the current distribution of emissions and wind patterns are similar to the 

historic distribution of emissions and wind patterns, and other factors (recognizing the 

limitations in the available air quality data) suggest a similar area to be contributing to 

potential violations in Illinois as the EPA found in promulgating designations for the 

1997 NAAQS. We agree with Missouri that future attainment/nonattainment boundaries 

may be different than those found in the TSD for the 1997 NAAQS, and inclusion as 

unclassifiable in this designation does not necessarily indicate this area would contribute 

to a future violation should one be found to exist.