ILLINOIS ENVIRONMENTAL PROTECTION AGENCY

1021 NORTH GRANO AVENUE EAST, P.O. Box 19506, SPRINGFIELD, ILLINOIS 62794··9506 (217) 782-2113

PAT QUINN, COVCRNOR

217/785-4140

217/782-9143 (TDD)

September 16, 2011

Ms. Cheryl A. Newton, Director

Office ofthe Air and Radiation Division

U.S. Environmental Protection Agency, Region V (RI8J)

77 West Jackson Boulevard

Chicago, Illinois 60604-3507

Re: Control Techniques Guidelines SIP Submittal and Redesignation Requests for 8-Hour

Ozone and P 25

Dear Ms. Ne~11;1

The Illinois Environmental Protection Agency (Illinois EPA), on behalfofthe State ofIllinois, is

making three requests regarding State Implementation Plan (SIP) requirements related to the

1997 8-hour ozone and fine particle (PM25) National Ambient Air Quality Standards (NAAQS).

First, the Illinois EPA hereby requests that the Illinois portion ofthe Chicago ozone

nonattainment area be redesignated to attainment ofthe 8-hour ozone standard promulgated in

1997. The Chicago ozone nonattainment area consists ofCook, Lake, DuPage, McHemy, Kane,

Will, and portions of Grundy and Kendall counties in Illinois, as well as Lalce and POlier

counties in northwest Indiana. The Illinois EPA understands that the State ofIndiana has already

submitted a similar redesignation request Ambient air monitoring data collected by the Illinois

EPA in the Chicago nonattainment area, as well as data collected in northwest Indiana and

southeast .Wisconsin, demonstrates that the area is currently meeting the 1997 8-hour ozone

NAAQS, and has been meeting tlle NAAQS since the 2006-2008 period. Note that U.S. EPA

published a Clean Data Determination for the Chicago ozone nonattainrnent area on April 12,

2010.

Second, the Illinois EPA requests that the Illinois portion ofthe S1. Louis ozone nonattainn1ent

area, known as the Metro-East area, be redesignated to attainment ofthe 8-hour ozone standard

promulgated in 1997. The Metro-East portion ofthe ozone nonattainment area consists of

Madison, Momoe, St Clair, and Jersey counties in Illinois. The Illinois EPA understands that

the State ofMissouri is making a similar redesignation request. Ambient air monitoring data

collected by the Illinois EPA in the Metro-East area, as well as data collected in Missouri,

demonstrates that the entire St. Louis nonattainment area is currently meeting the 1997 8-hour

ozone NAAQS, and has been meetingthe NAAQS since the 2007-2009 period. Note that U.S.

EPA published a Clean Data Determination for the St Louis ozone nonattainment area on July

11,2011.

PRINTED ON RECYCLED PAPER
Third, the Illinois EPA hereby requests that the Illinois portion ofthe Chicago PM25

nonattainment area be redesignated to attainment ofthe fme particle standard promulgated in

1997. The Chicago PM25 nonattainrnent area consists of Cook, Lake, DuPage, McHenry, Kane,

Will, and portions of Grundy and Kendall counties in Illinois, as well as Lake and Porter

counties in northwest Indiana. The Illinois EPA understands that the State ofIndiana has already

submitted a similar redesignation request. Ambient air monitoring data collected by the Illinois

EPA in the Chicago nonattainrnent area, as well as data collected in northwest Indiana,

demonstrates that the area is currently meeting the 1997 PM25 NAAQS, and has been meeting

the NAAQS since the 2007-2009 period. Note that U.S. EPA published a Clean Data

Determination for the Chicago PM25 nonattainrnent area on November 27,2009.

In support ofthese redesignation requests, the Illinois EPA submits the follovving amendments to

lllinois' SIP for ozone and PM25 :

• Reasonably Available Control Technology (RACT) for Volatile Organic Material

(VOM) Emissions from Group II and Group IV Consumer and Commercial

Products; Proposed Amendments to 35 lll. Adm. Code 211, 218, and 219;

• Final Maintenance Plan for the Illinois Portion ofthe Chicago Ozone

Nonattainrnent Area for the 1997 8-Hour Ozone National Ambient Air Quality

Standard;

• Final Maintenance Plan for the Metro-East Ozone Nonattainment Area for the

1997 8-Hour Ozone National Ambient Air Quality Standard;

• Final Maintenance Plan for the Chicago Nonattainment Area for the 1997 PM25

National Ambient Air Quality Standards.

The YOM RACT submittal is intended to meet the obligation ofthe State ofIllinois under the

Clean Air Act (CAA) to submit a revision to the SIP to address requirements under Sections 172

and 182 for sources ofVOM emissions in areas designated as nonattainment with respect to the

ozone NAAQS. This submittal addresses deficiencies identified by your staffin Illinois EPA's

previous submittal dated July 29, 2010. We have worked closely with your staffin this regard

and we believe this submittal is fully approvable. As you know, U.S. EPA did not identify

deficiencies in Illinois EPA's July 29, 2010 submittal with regards to the Group III Consumer

and Commercial Product Categories, so these rules have not been amended and are not included

in this submittal.

The Illinois EPA is also submitting Maintenance Plans for the Chicago and Metro-East 8-hour

ozone nonattainrnent areas, and the Chicago PM2.5 nonattainment area pursuant to Sections

107(d)(3)(E), 110(a)(2), and l75A ofthe CAA. InclUded with these plans are revised year 2025

motor vehicle emissions budgets developed using the MOVES model. The Maintenance Plans,

including the motor vehicle emissions budgets, are required as part ofthe Illinois EPA's

redesignation request. The Maintenance Plans provide the supporting information for this

request, consistent vvith the criteria for redesignation set forth in Section 175A ofthe CAA.

2
The Maintenance Plans constitute revisions ofIllinois' SIP for ozone and PM2.5. Accordingly,

the Illinois EPA held a public comment period and offered an opportunity for a public hearing.

The Public Notice was published in local newspapers on July 8, 2011, and also posted on the

Illinois EPA's web site. Due to receiving no requests for a hearing a hearing was not held.

However, the Illinois EPA did receive comments during the 30 day comment period. The

enclosed Responsiveness Summary summarizes the comments received and the Illinois EPA's

revisions to the Final Maintenance Plan to address these comments.

In order to assist with your review ofthese SIP submittals, two paper copies and an electronic

disk of all documents are enclosed. A list ofthe enclosed documents is also attached.

The Illinois EPA believes that these submittals, in conjunction with other submittals made

previoLlsly to the U.S. EPA, will allow the U.S. EPA to expeditiously take the necessary actions

to redesignate both the Chicago and Metro-East areas to attairunent for the 1997 8-hour ozone

standard and to redesignate the Chicago area to attairunent for the 1997 PM25 standards.

Iffurther information is required or should you have any questions, please feel free to contact

Rob Kaleel, Air Quality Planning Section, at (217) 524-4387.

Sincerely,

i<U~~

Laurel L. Kroack

Chief, Bureau ofAir

Attachments

3
Illinois State Implementation Plan

List ofEnclosed Documents

RACT for VOM Emissions from Group II and Group IV Consumer and Commercial

Products; Proposed Amendments to 35 III. Adm. Code 211, 218, and 219

1. Illinois EPA regulatory proposal, March 7, 2011 (certain docnments omitted)

2. Letter from Acting Chairman Girard to Director Ribley ofthe Department ofCommerce

and Economic Opportunity ("DCEO") regarding request for economic impact study,

March 17,2011

3. Order ofthe Board by A.S. Moore, accepting the Illinois EPA's regulatory proposal for

hearing, granting the Illinois EPA's request for waiver of copy requirements, and

ordering the clerk to tile the proposal for first notice publication in the Illinois Register,

March 17,2011 (full text ofrule omitted)

4. Hearing Officer Order, Notice ofHearings, March 17,2011

5. Illinois Register Notice of Proposed Amendments, 35 Ill. Reg. 4887, April 1, 2011 (full

text ofrule omitted)

6. Prefiled Testimony of David Bloomberg and Prefiled Testimony ofYoginder Mahajan of

Illinois EPA, April 14, 2011

7. Comments of Specialty Graphic Imaging Association, April 15, 2011

8. lllinois EPA's Motion to Amend Rulemaldng Proposal, April 25, 2011

9. Record ofHearing, April 27, 2011 (full transcript omitted)

10. Prefiled Testimony ofJames Sell, American Coatings Association, May 6, 2011

11. Post-Hearing Comments ofthe Illinois EPA, May 16,2011

12. Comments ofThe Boeing Company, filed May 17,2011

13. Record ofHearing, May 18, 2011 (full transcript omitted)

14. lllinois EPA's Request to Cancel [Third] Hearing and Motion to Correct Transcript, May

19,2011

15. Hearing Officer Order cancelling third hearing, May 20, 2011

4
16. Post-Hearing Comments ofthe Illinois EPA, June], 2011

17. Order ofthe Board by A.S. Moore, adopting the rule for second notice review by JCAR,

June 16,2011 (full text ofrule omitted)

18. Letter from JCAR to Acting Chairman Girard and Certification ofNo Objection to

Rulemaking Proposal, July 12, 2011

19. Final Order ofthe Board by A. S. Moore, adopting the rule and ordering the clerk to file

final rule for publication in Illinois Register, July 21,2011 (full text ofrule omitted)

20. Illinois Register Notice of Adopted Amendments, 35 Ill. Reg. 13451, August 12,2011

Maintenance Plans for the Chicago and Metro-East Ozone Nonattainment Areas for the

1997 8-Hour Ozone NAAQS, and the Chicago PMz.5 Nonattainment Area for the 1997

PMz.5 NAAQS

1. Final Maintenance Plan for the Illinois Portion of the Chicago Ozone Nonattainrnent

Area for the 1997 8-Hour Ozone National Ambient Air Quality Standard (Revised),

AQPSTR I ]~06, Illinois EPA, September 15,2011.

2. Final Maintenance Plan for the Metro-East Ozone Nonattainment Area for the 1997 8-

Hour Ozone National Ambient Air Quality Standard (Revised), AQPSTR 11-05, Illinois

EPA, August 18, 20 II.

3. Final Maintenance Plan for the Chicago Nonattainrnent Area for the 1997 PM2.5 National

Ambient Air Quality Standards (Revised), AQPSTR 11-07, Illinois EPA, August 17,

20]1.

4. Notice ofPublic Hearing and Comment Period, July 8, 2011.

5. Notice ofCancellation ofPublic Hearing. August 12,2011.

6. Comments ofthe Sierra Club, filed August 8, 2011.

7. Responsiveness Summary, Illinois EPA, September 13, 2011.

5
Maintenance Plan for the

Illinois Portion of the

Chicago Ozone Nonattainment Area

for the 1997 8-Hour Ozone Standard

(Revised)

AQPSTR 11-06

September 15, 2011

Illinois Environmental Protection Agency

1021 North Grand Avenue East

Springfield, Illinois 62794-9276
i

TABLE OF CONTENTS

 Page

LIST OF TABLES . . . . . . . . . iii

LIST OF FIGURES . . . . . . . . . iv

EXECUTIVE SUMMARY . . . . . . . . 5

1.0 INTRODUCTION . . . . . . . . 6

1.1 Regulatory Background . . . . . . 6

1.2 Status of Air Quality . . . . . . . 8

2.0 REDESIGNATION AND MAINTENANCE PLAN REQUIREMENTS 9

3.0 OZONE MONITORING . . . . . . . 11

3.1 Monitored Design Values . . . . . . 11

3.2 Quality Assurance . . . . . . . 12

3.3 Continued Monitoring . . . . . . 13

4.0 EMISSION INVENTORY . . . . . . . 14

4.1 Attainment Year Inventory – 2008 . . . . . 14

4.2 Air Quality Improvements and Emission Controls . . . 15

4.3 Emission Projections . . . . . . . 16

4.4 Demonstration of Maintenance . . . . . 17

4.5 Provisions for Future Updates . . . . . 18

5.0 CONTROL MEASURES AND REGULATIONS . . . 19

5.1 Attainment Demonstration Control Measures . . . 19

5.2 Reasonable Further Progress (RFP) . . . . 20

5.3 Reasonably Available Control Technology (RACT) . . . 20

5.4 Controls to Remain in Effect . . . . . . 22

5.5 Provisions for Permitting New or Modified Emission Sources . 22

5.6 Transportation Conformity . . . . . . 22

6.0 CONTINGENCY MEASURES . . . . . . 24

6.1 Contingency Measures . . . . . . 24

6.2 Commitment to Revise Plan . . . . . . 26

6.3 Public Participation . . . . . . . 26

6.4 Legal Authority to Implement and Enforce . . . . 27

7.0 CONCLUSIONS . . . . . . . . 28
ii

TABLE OF CONTENTS (Continued)

APPENDIX A Summary of Ambient Air Monitoring Data (2006-2008).......................... 29

APPENDIX B Transportation Conformity.............................................................. 32
iii

LIST OF TABLES

Page

Table 4.1 2008 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 14

Table 4.2 2002 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 15

Table 4.3 2015 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 16

Table 4.4 2020 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 17

Table 4.5 2025 Chicago Ozone Nonattainment Area

VOM and NOx Emissions . . . . . . 17

Table 4.6 Comparison of 2008, 2015, 2020, and 2025 Emission Estimates

Chicago Nonattainment Area . . . . . . 18

Table 5.1 Proposed Chicago Maintenance Year Plan 2008 and 2025 Motor 

Vehicle Emissions Budgets for the 1997 8-Hour Ozone NAAQS. . 23

Table 6.1 Contingency Plan for the Chicago 8-Hour Ozone

Nonattainment Area . . . . . . . 25
iv

LIST OF FIGURES

Page

Figure 1.1 Map of the Lake Michigan Ozone Nonattainment Areas . . 7

Figure 3.1 Ozone Monitors in the Lake Michigan Area . . . . 11

Figure 3.2 Comparison of 8-Hour Ozone Design Values for the 

Lake Michigan Region Between 2001-2003 and 2006-2008 . . 12
5

EXECUTIVE SUMMARY

This document describes Illinois’ Maintenance Plan for the Illinois portion of the 

Chicago ozone nonattainment area. A Maintenance Plan is required before the area can 

be redesignated from nonattainment to attainment of the 8-hour ozone National Ambient 

Air Quality Standard (NAAQS) promulgated in 1997. This document also provides 

technical information required to support a redesignation request. Illinois intends to 

submit such a request to the U. S. Environmental Protection Agency (U.S. EPA). This 

revision incorporates motor vehicle emissions estimates developed using the U.S. EPA’s 

MOVES model. The Illinois Environmental Protection Agency (Illinois EPA) has 

prepared this plan in consultation with the Indiana Department of Environmental 

Management (IDEM), the Wisconsin Department of Natural Resources (WDNR), and the

Michigan Department of Environmental Quality (MDEQ), the Lake Michigan Air 

Directors Consortium (LADCO), and the U.S. EPA. The IDEM has submitted a similar 

plan for the Indiana portion of the Chicago nonattainment area.

Ozone air quality has dramatically improved in the Lake Michigan region as a result of 

implementation of State and Federal control measures since the designation of the 

Chicago area as nonattainment in 2004. With the exception of Holland, Michigan, the 

entire Lake Michigan region, including the Chicago nonattainment area, has at least three 

years of complete, quality assured ambient air quality monitoring data for 2006-2008 that 

demonstrates compliance with the 1997 8-hour ozone NAAQS. These air quality 

improvements are due to permanent and enforceable emission control measures.

This Maintenance Plan provides for continued attainment of the 1997 8-hour ozone air 

quality standard for the Chicago nonattainment area for a period of ten years after U.S. 

EPA has formally redesignated the area to attainment. The Plan also provides assurances 

that, even if there is a subsequent violation of the air quality standard, measures listed in 

the Plan will prevent any future occurrences through contingency measures that would be 

triggered upon such an occurrence. Finally, the Plan includes on-road motor vehicle 

emissions budgets for use in transportation conformity determinations to assure that any 

increases in emissions from this sector do not jeopardize continued attainment of the 8-

hour ozone standard during the ten-year maintenance period.
6

1.0 INTRODUCTION

This document describes Illinois’ Maintenance Plan for the Illinois portion of the 

Chicago ozone nonattainment area. A maintenance plan is required before the area can 

be redesignated from nonattainment to attainment of the 8-hour ozone National Ambient 

Air Quality Standard (NAAQS) promulgated by the U. S. Environmental Protection 

Agency (U.S. EPA) in 1997. Illinois intends to submit such a request to the U.S. EPA in 

conjunction with this Maintenance Plan. The Illinois EPA has prepared this plan in 

consultation with the Indiana Department of Environmental Management (IDEM), the 

Wisconsin Department of Natural Resources (WDNR), and the Michigan Department of 

Environmental Quality (MDEQ), the Lake Michigan Air Directors Consortium 

(LADCO), and U.S. EPA. The IDEM has submitted a similar plan for the Indiana 

portion of the Chicago nonattainment area. With the exception of Holland, Michigan, the 

entire Lake Michigan region, including the Chicago area, has at least three years of 

complete, quality assured ambient air quality monitoring data for 2006-2008, 

demonstrating attainment with the 1997 8-hour ozone NAAQS.

This document also provides the technical information needed to support a request to 

redesignate the Chicago area to attainment of the 8-hour ozone NAAQS. Section 107 of 

the Clean Air Act (CAA) establishes specific requirements to be met in order for a 

nonattainment area to be considered for redesignation. Before an area can be reclassified 

to attainment, U.S. EPA must make a determination that the area has attained the 8-hour

ozone NAAQS based on at least three complete years of ambient monitoring data. U.S. 

EPA must have approved a State Implementation Plan (SIP) for the area under Section 

110 and Part D of the CAA. The state must demonstrate that the improvement in air 

quality is due to permanent and enforceable reductions in emissions resulting from 

implementation of the SIP and other federal requirements. Finally, the state must submit, 

and U.S. EPA must approve, a maintenance plan under Section 175(A) of the CAA, 

including provisions for contingency measures that will be implemented if future 

violations of the 8-hour ozone NAAQS are measured.

This Maintenance Plan provides for the continued attainment of the 8-hour ozone 

NAAQS for the Chicago nonattainment area (NAA) for a period of at least ten years after 

U.S. EPA has formally redesignated the area to attainment. The Plan also provides 

assurances that even if a subsequent violation of the ozone NAAQS occurs, provisions in 

the Plan will prevent any future occurrences through contingency measures that would be 

triggered upon such occurrence.

This document addresses the maintenance plan requirements established by the CAA and 

U.S. EPA, and includes additional information to support continued compliance with the 

8-hour ozone NAAQS.

1.1 Regulatory Background

The CAA, as amended in 1990, requires areas that fail to meet the NAAQS for ozone to 

develop SIPs to expeditiously attain and maintain the NAAQS. Historically, exceedances 

of the ozone NAAQS have been monitored in Cook and Lake Counties in Illinois, and in 
7

portions of Wisconsin, Indiana, and Michigan immediately downwind of the Chicago, 

Gary, and Milwaukee metropolitan areas.

The Chicago NAA, which includes Lake and Porter Counties in northwest Indiana, was 

originally designated as nonattainment in 2004 pursuant to the 1997 revisions to the 

ozone NAAQS. Several counties in eastern Wisconsin, and one county in western 

Michigan adjacent to Lake Michigan were also designated as nonattainment of the 8-hour

ozone NAAQS, although these areas are separate from the Chicago NAA. Figure 1.1 

depicts the current NAAs in the Lake Michigan region.

Figure 1.1

Map of the Lake Michigan Ozone Nonattainment Areas

The following is a list of the counties, and portions thereof, contained in the Chicago 8-

hour ozone severe nonattainment area:

Cook County, IL

Lake County, IL

DuPage County, IL

McHenry County, IL
8

Kane County, IL

Will County, IL

Grundy County, IL (Aux Sable and Goose Lake Townships)

Kendall County, IL (Oswego Township)

Lake County, IN

Porter County, IN

As a result of the designation as nonattainment and the accompanying classification as 

moderate, these areas were subject to new requirements, including development of a plan 

demonstrating that the area would meet the federal 8-hour NAAQS for ozone by June 15, 

2010.

Recognizing the need for a regional solution, the States of Illinois, Indiana, Michigan, 

Ohio, and Wisconsin worked cooperatively, under the auspices of the Lake Michigan Air 

Directors Consortium (LADCO), to jointly develop and evaluate an effective regional 

attainment strategy to enable the Lake Michigan region to attain the 8-hour ozone 

NAAQS. The attainment strategy recognizes the importance of both locally generated 

ozone precursor emissions and the need for significant reductions of incoming 

(transported) ozone and ozone precursor emissions (including oxides of nitrogen, or 

NOx) to allow the States to attain the NAAQS. The emission reductions needed to attain 

the 8-hour ozone NAAQS include both State and Federal measures that have reduced 

ozone precursor emissions both locally and regionally. These measures have allowed the 

Chicago nonattainment area to attain the 8-hour ozone standard by the attainment 

deadline established by the U.S. EPA.

1.2 Status of Air Quality

Ozone monitoring data for the most recent three-year period, 2006 through 2008, 

demonstrates that air quality has met the 1997 8-hour ozone NAAQS in the entire Lake 

Michigan region, including the Chicago nonattainment area, with the exception of 

Holland, Michigan. Modeling performed by LADCO shows that Holland, MI will attain 

the 1997 ozone NAAQS by 2012.
9

2.0 REDESIGNATION AND MAINTENANCE PLAN REQUIREMENTS

Sections 107 and 110 of the CAA list a number of requirements that must be met by 

nonattainment areas prior to consideration for redesignation to attainment. One of those 

requirements is the maintenance plan, which describes a state’s plan for maintaining the 

NAAQS for a ten-year period after redesignation to attainment. U.S. EPA has published 

guidance for the preparation of maintenance plans and redesignation requests. This 

guidance is contained in a document entitled ―Procedures for Processing Requests to 

Redesignate Areas to Attainment‖ (September 4, 1992).

Before a redesignation to attainment can be promulgated, U.S. EPA must:

Determine that the NAAQS for ozone, as published in 40 CFR 50.4, has been 

attained. Ozone monitoring data must show that violations of the ambient 

NAAQS are no longer occurring. This showing must rely on three consecutive 

years of data. The ambient air monitoring data must be quality assured in 

accordance with 40 CFR 58.10, recorded in U.S. EPA’s Air Quality System 

(AQS) data base, and is available to the public.

Approve the state’s plan for demonstrating attainment. The attainment plan, 

which is based on air quality modeling, must contain enforceable control 

measures and must be submitted as a revision to the state’s SIP after a public 

hearing.

Determine that the improvement in air quality between the year violations 

occurred and the year that attainment was achieved is based on permanent and 

enforceable emission reductions.

Approve the state’s maintenance plan. The requirements for the maintenance plan 

are discussed below.

Determine that all other requirements applicable to nonattainment areas have been 

met.

A maintenance plan provides for the continued attainment of the 8-hour ozone NAAQS 

for a nonattainment area for a period of ten years after U.S. EPA has formally 

redesignated the area to attainment. The plan also provides assurances that even if a 

subsequent violation of the NAAQS occurs, provisions in the plan will prevent any future 

occurrences through contingency measures that would be triggered upon such 

occurrence. To be approvable, the state is required to have a public comment period and 

provide the opportunity for a public hearing on the Maintenance Plan prior to adoption. 

The maintenance plan must contain the following elements:

A comprehensive emission inventory of the precursors of ozone completed for the 

―attainment year‖;
10

A projection of the emission inventory forward to a year at least ten years after 

redesignation and a demonstration that the projected level of emissions is 

sufficient to maintain the ozone NAAQS;

A commitment that, once redesignated, the state will continue to operate an 

appropriate monitoring network to verify maintenance of the attainment status;

A demonstration of legal authority to implement and enforce all control measures 

contained in the SIP;

Provisions for future updates of the inventory to enable tracking of emission 

levels, including an annual emission statement from major sources;

Motor vehicle emissions budgets for transportation conformity for the ten-year 

maintenance period;

A commitment to submit a revised maintenance plan eight years after 

redesignation;

A commitment to enact and implement additional contingency control measures 

expeditiously in the event that future violations of the NAAQS occur;

A list of potential contingency measures that would be implemented in such an 

event.

Illinois’ Maintenance Plan has been prepared in accordance with the requirements 

specified in U.S. EPA’s guidance document and additional guidance received from U.S. 

EPA staff.

The following sections of this document describe how U.S. EPA’s requirements have 

been met.
11

3.0 OZONE MONITORING

U.S. EPA’s published guidance document, ―Procedures for Processing Requests to 

Redesignate Areas to Attainment‖ (September 4, 1992), details specific requirements 

regarding the collection and use of ambient air monitoring data needed to support a 

redesignation request. Before the Chicago NAA can be redesignated, Illinois must 

demonstrate that the NAAQS for ozone, as published in 40 CFR 50.4, has been attained. 

Ozone monitoring data must show that violations of the NAAQS are no longer occurring 

within the nonattainment area. This showing must rely on three complete, consecutive 

calendar years of quality assured data. Further, the air monitoring data must be quality 

assured in accordance with 40 CFR 58.10, recorded in U.S. EPA’s AQS data base, and 

made available to the public. Finally, Illinois must commit to continue to operate an 

appropriate monitoring network to verify the maintenance of the attainment status, once 

the area has been redesignated.

The following subsections describe how each of these requirements has been addressed.

3.1 Monitored Design Values

Currently there are 55 ozone monitors located in the nonattainment counties in the Lake 

Michigan region; 9 are located in northwestern Indiana, 17 in northeastern Illinois, 13 in 

western Michigan, and 16 in eastern Wisconsin. 

 

Figure 3.1 Ozone Monitors in the Lake Michigan Area

To determine whether the NAAQS is being exceeded, the design value must be 
12

calculated. The current U.S. EPA method for calculating the ozone design value is to

average the 4th highest daily maximum 8-hour value for each year over the 3-year period. 

The calculated 8-hour ozone design values for the monitors in the Lake Michigan region 

for 2006-2008 are included as Appendix A of this report. Figure 3.2 compares the design 

values for the 2001-2003 period for monitoring stations in the Lake Michigan region to 

the corresponding design values from 2006-2008. The data demonstrate that ozone air 

quality has improved dramatically throughout the Lake Michigan region and that the 

NAAQS for ozone has been attained for the 2006-2008 period at all locations except 

Holland, Michigan.

Figure 3.2

Comparison of 8-Hour Ozone Design Values for the Lake Michigan Region

Between 2001-2003 and 2006-2008

 2001-2003 2006-2008 

3.2 Quality Assurance

Illinois EPA has quality assured all data shown in Appendix A for all sites located in 

Illinois in accordance with 40 CFR 58.10 and the Illinois EPA ’s Quality Assurance Plan, 
13

which describes Illinois EPA’s standard operating procedures for operating the ambient 

monitoring network and validating the data. The other states in the Lake Michigan 

region have similar quality assurance plans. Illinois EPA has recorded the data in the 

U.S. EPA’s AQS database, as have the other Lake Michigan states. U.S. EPA’s AQS 

database is available to the public.

3.3 Continued Monitoring

Illinois commits to continue monitoring ozone levels according to a U.S. EPA approved 

monitoring plan, as required to ensure maintenance of the ozone NAAQS. Should 

changes in the location of an ozone monitor become necessary, Illinois EPA will work 

with U.S. EPA to ensure the adequacy of the monitoring network. Illinois EPA will 

continue to quality assure the monitoring data to meet the requirements of 40 CFR 58. 

Illinois EPA will continue to enter all data into AQS on a timely basis in accordance with 

federal guidelines.
14

4.0 EMISSIONS INVENTORY

A redesignation request must contain a demonstration that the improvement in air quality 

between the year that violations occurred and the year that attainment was achieved is 

based on permanent and enforceable emission reductions. As described previously in 

Section 3.0, a three-year monitoring period is used to evaluate whether attainment has 

been achieved. In this Section, the ―attainment year‖ refers to the last year (2008) of the 

three-year period (2006-2008) used to demonstrate attainment. The request should also 

include a projection of the emission inventory to a year at least 10 years following 

redesignation, a demonstration that the projected level of emissions is sufficient to 

maintain the ozone NAAQS, and a commitment to provide future updates of the 

inventory to enable tracking of emission levels during the 10-year maintenance period.

4.1 Attainment Year Inventory, 2008

Illinois EPA has prepared a comprehensive emissions inventory for the Illinois portion of 

the Chicago ozone nonattainment area, including point, area, and on-road and off-road 

mobile sources for precursors of ozone (VOM and NOx) for the attainment year, 2008. 

Point source information was compiled from 2008 annual emission reports submitted to 

the Illinois EPA by emission sources and the U.S. EPA’s Clean Air Markets Division 

database for electric utilities. Area source emissions were ―grown‖ from 2002 activity 

levels appropriate for each source category. Biogenic emissions are not included in these 

summaries. On-road mobile source emissions were calculated using U.S. EPA’s 

MOVES emissions model with vehicle miles traveled (VMT) data provided by the 

Illinois Department of Transportation (IDOT). Off-road mobile source emissions were 

calculated using U.S. EPA’s NONROAD emissions model.

Table 4.1 summarizes the 2008 emissions estimates for the Chicago ozone nonattainment 

area. This summary has been revised to incorporate emissions estimates for on-road 

mobile sources using U.S. EPA’s MOVES model.

Table 4.1

2008 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 53.27 154.50

Area Sources 351.51 38.56

On-Road Mobile Sources 117.23 373.52

Off-Road Mobile Sources 265.44 330.18

Total 787.45 896.76
15

4.2 Air Quality Improvements and Emission Controls

The Chicago area was designated nonattainment in 2004, based on ozone air quality 

monitoring data collected between 2001 and 2003. Since that time, permanent and 

enforceable reductions of ozone precursor emissions have contributed to improvements in 

ozone air quality and to the attainment of the ozone NAAQS. Some of these emission 

reductions were due to the application of tighter federal emission standards on motor

vehicles and fuels, and some due to the requirements of the federal NOx SIP Call. 

Section 5.0 of this report describes these reductions in more detail, along with an 

explanation of their regulatory status. In this subsection, the emission levels from 2008

are compared to emission levels estimated in 2002 when the Chicago area was first 

proposed for a nonattainment designation for the 1997 8-hour ozone standard.

U.S. EPA’s 8-hour ozone Implementation Rule required that states with ozone 

nonattainment areas prepare and submit a 2002 base year anthropogenic inventory of 

sources of ozone precursor emissions. The base year inventory included emissions from 

point, area, on-road mobile and off-road mobile emissions. Illinois EPA prepared and 

submitted this inventory in June 2006. Table 4.2 summarizes 2002 emissions by major 

source category and by pollutant for the Illinois portion of the Chicago nonattainment 

area. This summary has been revised to incorporate emissions estimates for on-road 

mobile sources using U.S. EPA’s MOVES model.

Table 4.2

2002 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 76.62 307.73

Area Sources 520.21 42.93

On-Road Mobile Sources 168.06 540.13

Off-Road Mobile Sources 233.77 326.65

Total 998.66 1,217.44

Comparing the 2002 inventory to that for 2008 indicates that total VOM emissions in the 

Chicago area decreased by about 210 tpd, while NOx emissions in the Chicago NAA 

decreased by about 320 tpd during the same time period. These sizeable emission 

reductions in ozone precursor emissions, plus reductions in upwind areas in Illinois and 

other nearby states, resulted in a substantial improvement in ozone air quality in the 

Chicago area, ultimately resulting in attainment of the 1997 8-hour ozone NAAQS.
16

4.3 Emission Projections

A maintenance plan must contain a demonstration that the level of emissions projected 

for the ten-year period following redesignation are sufficient to maintain the ozone 

NAAQS. Accordingly, Illinois EPA has projected VOM and NOx emissions for the 

Illinois portion of the Chicago nonattainment area for 2025. Illinois EPA has also 

projected emissions to 2015 and 2020, to represent two midpoints during the 

maintenance period. Emissions for these three projection years are compared to emission 

levels in 2008 to determine if emissions are sufficient to maintain the NAAQS during this 

period.

Chicago area point source emissions for 2015, 2020, and 2025 were estimated using the 

2002 base year inventory and growth factors appropriate for each source category. Area 

source emissions were projected by applying category-specific growth factors to 

estimates contained in the 2002 base year inventory. County population projections for 

2015, 2020, and 2025 were used to estimate emissions for categories which rely on a per 

capita emissions factors. Off-road emissions projections were also developed using the 

2002 inventory and growth factors contained in U.S. EPA’s NONROAD model. On-road 

motor vehicle emissions were estimated using U.S. EPA’s MOVES motor vehicle 

emissions model. The figures assume the continued use of reformulated gasoline, the 

continued phase-in of the Tier 2 motor vehicle emissions standards, and operation of an 

enhanced vehicle inspection and maintenance program. Total vehicle miles of travel 

(VMT) for 2015, 2020, and 2025 were assumed to increase at a rate of 1.5 percent per 

year from 2002.

Tables 4.3, 4.4, and 4.5 include the VOM and NOx emissions estimates for the years 

2015, 2020, and 2025, respectively, for the Illinois portion of the Chicago nonattainment 

area.

Table 4.3

2015 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 62.02 150.06

Area Sources 363.86 39.85

On-Road Mobile Sources 50.33 197.14

Off-Road Mobile Sources 90.83 106.36

Total 567.04 493.41
17

Table 4.4

2020 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 67.63 171.13

Area Sources 385.73 40.57

On-Road Mobile Sources 37.98 116.69

Off-Road Mobile Sources 84.16 84.34

Total 575.50 412.73

Table 4.5

2025 Chicago Ozone Nonattainment Area

VOM and NOx Emissions

(Emissions stated in tons per ozone season weekday)

Source Category VOM NOx

Point Sources 72.79 180.13

Area Sources 406.96 41.35

On-Road Mobile Sources 41.85 108.93

Off-Road Mobile Sources 90.25 96.70

Total 611.85 427.11

4.4 Demonstration of Maintenance

Table 4.6 demonstrates that the level of emissions projected for the ten-year period 

following redesignation is sufficient to maintain the ozone NAAQS. As shown in the 

table, both VOM and NOx emissions within the nonattainment area are expected to 

decrease significantly between 2008 and 2025. Projected VOM and NOx emissions for 

the mid-point years, 2015 and 2020, are also less than the emission levels in 2008. Based 

on these emission trends it is expected that air quality will continue to meet the 8-hour

ozone NAAQS throughout the maintenance period.

In addition to the overall emission reductions projected to occur within the nonattainment 

area, significant reductions of statewide NOx emissions resulting from implementation of 

Illinois’ multi-pollutant standards affecting electric utilities by 2012, will also help to 

ensure continued attainment of the 8-hour ozone NAAQS. 
18

TABLE 4.6

Comparison of 2008, 2015, 2020, and 2025 Emission Estimates 

Chicago Nonattainment Area

(Emissions stated in tons per ozone season weekday)

2008 2015

Difference

(2008 –

2015)

2020

Difference

(2008 –

2020)

 

2025

Difference

(2008-

2025)

VOM 787.45 567.04 220.41 575.50 211.95 611.85 175.60

NOx 896.76 493.41 403.35 412.73 484.03 427.11 469.65

4.5 Provisions for Future Updates

As required by Section 175A(b) of the CAA, Illinois commits to submit to U.S. EPA, 

eight years after redesignation, a revised version of this Maintenance Plan. The revision 

will contain Illinois’ plan for maintaining the 8-hour ozone NAAQS for ten years beyond 

the first 10-year period after redesignation.
19

5.0 CONTROL MEASURES AND REGULATIONS

This section provides specific information on the control measures implemented in the 

Chicago nonattainment area, including the measures that were part of Illinois’ Attainment 

Demonstration, Reasonable Further Progress (RFP) demonstration, CAA requirements, 

and other state and federal measures. The control measures required in past ozone SIP 

revisions have been fully implemented, and other, more recent control programs will 

continue to provide emission reductions in future years. Illinois EPA commits to keep 

these measures in effect after redesignation, or to provide equivalent emissions levels 

using alternate measures. Illinois’ SIP contains acceptable provisions to provide for 

preconstruction review of new emission sources. After redesignation to attainment, 

Prevention of Significant Deterioration (PSD) requirements will apply to the construction 

of new major sources and to significant modifications of existing sources. Illinois has 

accepted delegation from U.S. EPA of this program. Illinois further commits to continue 

to require that all future transportation plans in the Chicago area conform with the SIP.

5.1 Attainment Demonstration Control Measures

Illinois’ attainment demonstration for the Chicago nonattainment area identifies control 

measures that have been promulgated at either the state or federal level that are sufficient 

to allow the Lake Michigan region, with the exception of Holland, MI, to meet the 1997 

8-hour ozone NAAQS by the required attainment date. The attainment demonstration, 

which was submitted to U.S. EPA after a public hearing and public comment period, is 

described in the Illinois EPA’s document: ―Attainment Demonstration for the 1997 8-

Hour Ozone National Ambient Air Quality for the Chicago Nonattainment Area‖ (Report 

Number AQPSTR 09-03, March 18, 2009). The primary emission reduction measures 

for demonstrating attainment of the ozone standard are as follows:

NOx SIP Call 

New Source Performance Standards (NSPS) and National Emission Standards for 

Hazardous Air Pollutants (NESHAPS)/Maximum Achievable Control 

Technology (MACT) Standards 

VOM Solvent Categories: Aerosol Coatings, Architectural and Industrial 

Maintenance (AIM) Coatings, Consumer Solvents 

Enhanced Vehicle Inspection & Maintenance Program 

Reformulated Gasoline 

Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control 

Requirements
20

On-Highway Heavy-Duty Engine and Vehicle Standards and Highway Diesel 

Fuel Sulfur Control Requirements 

Federal Control Programs Incorporated into NONROAD Model (e.g., Nonroad 

Diesel Rule), plus Evaporative Large Spark Ignition and Recreational Vehicle 

Standards 

Tier 4 Nonroad Diesel Engine Standards and Diesel Fuel Sulfur Content 

Restrictions 

Marine Compression-Ignition Engine Standards and Locomotive Engine 

Standards 

Consent Decrees---Dynegy Midwest Generation, ConocoPhillips, CITGO, 

Exxon-Mobil, Marathon Ashland, Archer Daniels Midland 

5.2 Reasonable Further Progress (RFP)

Since the Chicago region is classified as a moderate nonattainment area for the 8-hour 

ozone standard, a 15 percent net reduction in VOM emissions from 2002 levels was

required by 2008 in order to meet the RFP requirement. The Illinois EPA did not rely on

NOx substitution to meet its 15 percent RFP reduction, relying solely on VOM emission 

reductions. 

Reductions in VOM emissions are primarily achieved through implementation of the 

control measures listed in Section 5.1.

The RFP demonstration is contained in Illinois EPA’s document: ―Chicago 

Nonattainment Area 8-Hour Ozone Reasonable Further Progress Demonstration‖,

(Report Number AQPSTR 09-05, March 18, 2009). The control measures identified in 

the RFP document, including those listed above, will result in a 15.7 percent reduction in 

VOM emissions from 2002 emissions levels by the year 2008. In addition, continuing 

reductions in 2009 and 2010 are estimated to result in year 2010 VOM emissions at 21.0

percent below 2002 levels. These emission reductions achieve the 15% RFP target for 

the Chicago nonattainment area.

5.3 Reasonably Available Control Technology (RACT)

Pursuant to Sections 172, 182(b) and (f) of the CAA, RACT is required for all existing 

major sources of the applicable criteria pollutant and its precursors (VOM and NOx) 

located in NAAs. U.S. EPA defines RACT as the lowest emission limitation that a 

particular source is capable of meeting by the application of control technology that is 

reasonably available considering technological feasibility and economic reasonableness 

(70 FR 71612; November 29, 2005). The major source threshold for moderate NAAs is 

defined as 100 tpy. A source generally consists of several units that emit pollutants. The 
21

sum of emissions from all units at the source determines if a unit is major and thus 

subject to RACT requirements. 

RACT is not a new requirement under the CAA. Illinois previously addressed RACT 

requirements in the Chicago area in developing attainment plans for the 1-hour ozone 

standard. (See 35 Ill. Adm. Code Part 218) The Illinois EPA has evaluated the 

previously adopted regulations to determine if the RACT requirement is still being met 

for 8-hour ozone. The RACT requirement for NOx was waived for the 1997 8-hour 

ozone standard, based on U.S. EPA’s finding that additional NOx reductions were not 

needed for the area to attain the standard. 

Sections 172, 182(b)(2), and 182(f) of the CAA require implementation of RACT for 

sources that are subject to Control Techniques Guidelines (CTGs) that are promulgated 

by U.S. EPA. The U.S. EPA has issued CTGs defining RACT for those categories of 

sources that emit the greatest amounts of VOM emissions. Illinois EPA has proposed 

regulations to implement the revised CTGs issued by the U.S. EPA in 2006, 2007, and 

2008. The 2006 CTG’s addressed industrial cleaning solvents, offset lithographic 

printing and letterpress printing, flexible package printing, and flat wood paneling 

coatings. The 2007 CTG’s address paper, film, and foil coatings, large appliance 

coatings, and metal furniture coatings. The 2008 CTG’s address miscellaneous metal and 

plastic parts coatings, fiberglass boat manufacturing materials, miscellaneous industrial

adhesives, and automobile and light-duty truck assembly coatings. Other than the above 

mentioned CTGs, Illinois has adopted applicable rules addressing all CTGs published by 

U.S. EPA for which there are existing sources in the Chicago NAA. 

Non-CTG sources are defined as major VOM sources which are not subject to CTGs, but 

for which RACT is required. All major sources of ozone precursors located in the ozone 

NAA that are not subject to individual RACT rules are subject to a generic RACT rule. 

These rules apply to non-CTG sources that have the potential to emit 100 tons or more 

per year of VOM. Thus, Illinois has met the obligation to implement RACT on non-CTG 

VOM sources in the NAA. 

It should be noted that other regulatory requirements also affect VOM emission sources 

within the Chicago ozone NAA. These include Maximum Achievable Control 

Technology (MACT), federal New Source Performance Standards (NSPS), and National 

Emission Standards for Hazardous Air Pollutants (NESHAPS). These programs satisfy

the RACT requirements for specific source categories because these rules are more 

stringent than RACT. It is concluded from this review that Illinois’ existing VOM RACT 

rules fulfill U.S. EPA’s RACT requirements for VOM sources in the NAA.

As mentioned previously, the RACT requirement for NOx was waived under the 1997 8-

hour ozone NAAQS. Although the Illinois EPA has adopted NOx RACT rules, the 

attainment demonstration for the Chicago NAA for the 1997 ozone NAAQS did not rely 

on emission reductions from the Illinois EPA’s NOx RACT rules. The reductions 

resulting from this program, when implemented, will help the area to maintain the 

NAAQS in future years.
22

5.4 Controls to Remain in Effect

Illinois will maintain all of the control measures listed in this Section to ensure 

maintenance of the 8-hour ozone NAAQS. Any revisions to the control measures 

included as part of the Maintenance Plan will be submitted as a SIP revision to U.S. EPA 

for approval, and will be accompanied by a showing that such changes will not interfere 

with maintenance of the NAAQS.

Illinois EPA has the necessary resources to enforce any violations of its rules or permit 

provisions. After redesignation, it intends to continue enforcing all rules that relate to the 

emission of ozone precursors in the Chicago nonattainment area.

5.5 Provisions for Permitting New or Modified Emission Sources

Illinois has longstanding and fully implemented programs for the review of new major 

sources and significant modifications of existing sources. The Prevention of Significant 

Deterioration (PSD) program, which includes requirements for Best Available Control 

Technology (BACT) on major new sources or significant modifications of existing 

sources, will be applicable in the Chicago area once the area has been redesignated to 

attainment. Illinois has been delegated full authority to implement the PSD program by 

U.S. EPA.

5.6 Transportation Conformity

The purpose of this section is to describe and establish the Chicago nonattainment area 

motor vehicle emissions budgets associated with the 8-hour ozone Maintenance Plan SIP. 

Average summer weekday motor vehicle emissions budgets are being proposed for the 

attainment year, 2008, and the final year of the Maintenance Plan, 2025, for the precursor 

pollutants VOM and NOx. Although the Maintenance Plan includes motor vehicle 

emissions estimates for the milestone years 2015 and 2020, these years are not being 

proposed as motor vehicle emissions budgets. The 2008 and 2025 budgets were 

developed consistent with the motor vehicle activity assumptions and emissions control 

strategies incorporated into the 8-hour ozone attainment demonstration analysis. The 

budgets reflect an emissions level determined using motor vehicle VMT and fleet mix 

provided by the Chicago Metropolitan Agency for Planning (CMAP) and are consistent 

with the emission levels used in the attainment demonstration. 

A motor vehicle emissions budget is that portion of the total allowable emissions 

allocated to highway and transit vehicle use that are defined in the SIP for a certain year. 

The rules governing transportation conformity require certain transportation activities to 

be consistent with motor vehicle emissions budgets contained in control strategy 

implementation plans (40 CFR § 93.118). Section 93.101 of the rule defines a ―control 

strategy [State] implementation plan revision‖ as a ―plan which contains specific 

strategies for controlling the emissions and reducing ambient levels of pollutants in order 

to satisfy CAA requirements of reasonable further progress and attainment.‖ In order to 
23

demonstrate conformity to the motor vehicle emissions budget, emissions from the 

implementation of a transportation plan or a transportation improvement program must 

be less than or equal to the budget level (40 CFR § 93.118(a)).

The motor vehicle emissions budgets established and described herein were developed 

consistent with the methodology and control strategy assumptions used in the 8-hour 

ozone attainment demonstration. The effects of motor vehicle control measures are 

incorporated into the emissions factors produced by the U.S. EPA’s MOVES model. 

These control measures include motor vehicle emissions standards, the operation of a 

vehicle inspection and maintenance (I/M) program, and the required use of reformulated 

gasoline and low sulfur gasoline and diesel fuel.

The Maintenance Plan emissions analysis summarized in Table 4.6 estimates that VOM 

and NOx emissions will be 175.60 and 469.65 tons per day, respectively, less in 2025 

than the 2008 attainment year emissions levels. The transportation conformity 

regulations (40 CFR § 93.118(a)) allow the addition of a portion of this ―safety margin‖ 

to the motor vehicle emissions estimates. As year 2025 emissions levels are projected to 

be substantially less than the attainment year 2008 emissions, a 15% safety margin is 

being proposed to be added to the 2025 estimated motor vehicle emissions to make up the 

motor vehicle emissions budget. The 15% increase would equate to an increase of 6.28 

tpd of VOM and 16.34 tpd of NOx.

The motor vehicle emissions budgets, which reflect the VMT, control program 

assumptions and safety margin are listed in Table 5.1.

Table 5.1

Proposed Chicago 8-hour Ozone Maintenance Plan

2008 and 2025

Motor Vehicle Emissions Budgets

(tons per ozone season weekday)

Estimated Emissions Safety Margin Motor Vehicle 

Emissions Budgets

Year VOM NOx VOM NOx VOM NOx

2008 117.23 373.52 - - - - 117.23 373.52

2025 41.85 108.93 6.28 16.34 48.13 125.27

Complete details on the derivation of the motor vehicle emissions budgets, including 

discussion of the MOVES model inputs and assumptions are included in Appendix B of 

this report.
24

6.0 CONTINGENCY MEASURES

6.1 Contingency Measures

Section 175(A) of the CAA specifies the requirements for maintenance plans, including 

provisions for contingency measures that will be implemented if violations of the 8-hour

ozone NAAQS are measured after redesignation to attainment. A list of potential 

contingency measures that would be implemented in such an event should also be 

included in the Maintenance Plan. Finally, the plan should provide a commitment to 

submit a revised maintenance plan eight years after redesignation to ensure continued 

maintenance for the next ten-year maintenance period.

Contingency measures are intended to provide further emission reductions in the event 

that violations of the 8-hour ozone NAAQS occur after redesignation to attainment. 

While these measures do not need to be fully adopted by the IPCB prior to the occurrence 

of NAAQS violations, the contingency plan should ensure that the contingency measures 

are adopted expeditiously once they are triggered. The Maintenance Plan must identify 

the triggers that determine when contingency measures will be adopted, and the measures 

that the state will consider.

Illinois EPA’s contingency plan for the Chicago NAA is described in Table 6.1. 

Consistent with this plan, Illinois agrees to adopt and implement, as expeditiously as is 

practicable, the necessary corrective actions in the event that violations of the 8-hour

ozone NAAQS occur within the Chicago maintenance area after redesignation to 

attainment. Further, Illinois commits to continue to implement the control measures 

identified in the attainment demonstration and RFP demonstration. As described in 

Section 5.0 of this report, Illinois has adopted and is continuing to implement a range of 

control measures that will greatly reduce precursor emissions, both locally and statewide. 

The contingency plan anticipates that these emission reductions will be sufficient to 

mitigate exceedances or violations of the NAAQS that may occur in the coming years 

without further regulatory action. 

The contingency plan provides for different levels of corrective responses should ambient

8-hour ozone levels exceed the NAAQS in any year, if emissions in the NAA increase 

significantly above current attainment levels, or if the NAAQS is violated. A Level I 

response would occur in the event that: 1) the fourth highest 8-hour ozone concentration

at any monitoring site in the Chicago NAA exceeds 84 ppb in any year, or 2) if VOM or 

NOx emissions increase more than 5% above the levels contained in the attainment year 

(2006) emissions inventory. It should be noted that U.S. EPA does not require a state to 

implement contingency measures when occasional exceedances are recorded. Illinois 

EPA’s voluntary commitment to initiate a Level I response is intended to prevent future 

violations of the NAAQS from ever occurring.

Illinois commits to compiling VOM and NOx emissions inventories every three years for 

the duration of the Maintenance Plan to facilitate the emissions trends analysis included 
25

Table 6.1

Contingency Plan for the Chicago 8-Hour Ozone Nonattainment Area 

 

Contingency Measure 

Trigger Action to be Taken List of Potential Contingency Measures

Level I Trigger

Fourth highest 

monitored 8-hour 

average ozone 

concentration 

exceeding 84 ppb in 

any year at any 

monitoring station in 

the Chicago 

maintenance area.

The Chicago 

maintenance area’s 

NOx or VOM 

emissions inventories 

increase more than 

5% above the levels 

included in the 2006 

emissions inventories.

IL will evaluate air quality, or 

determine if adverse emissions trends 

are likely to continue. If so, IL will 

determine what and where controls 

may be required, as well as level of 

emissions reductions needed, to avoid a 

violation of the NAAQS. The study 

shall be completed within 9 months. If 

necessary, control measures shall be 

adopted within 18 months of 

determination and implemented as 

expeditiously as practicable, taking into 

consideration the ease of 

implementation and the technical and

economic feasibility of the selected 

measures. 

Point Source Measures

IL Multi-Pollutant Program for 

electric generating units

NOx RACT 

Clean Air Transport Rule, after 

promulgation by USEPA

Best Available Retrofit 

Technology (BART)

Broader geographic applicability 

of existing measures

Mobile Source Measures

Tier 2 Vehicle Standards and Low 

Sulfur Fuel

Heavy Duty Diesel Standards and 

Low Sulfur Diesel Fuel

High-enhanced I/M (OBDII)

Federal railroad/locomotive 

standards

Federal commercial marine vessel

engine standards

Portable fuel containers

Area Source Measures

Architectural/Industrial 

Maintenance (AIM) Coatings

Commercial and Consumer 

Products

Aerosol coatings

Level II Trigger

A violation of the 

NAAQS at any 

monitoring station in 

the Chicago

maintenance area.

IL will conduct a thorough analysis to 

determine appropriate measures to 

address the cause of the violation. 

Analysis shall be completed within 6 

months. Selected measures shall be 

implemented within 18 months of a 

violation.

in the contingency plan under Level I. Illinois will coordinate with LADCO and other 

Lake Michigan states to evaluate the causes of high ozone levels or the emissions trends 

and to determine appropriate control measures needed to assure continued attainment of 

8-hour ozone NAAQS. Under Level I, measures that could be implemented in a short 

time would be selected so as to be in place quickly after the Illinois EPA is aware that 

corrective measures have been triggered. Control measures selected under Level I will be 

adopted in most cases within 18 months after a determination is made, and implemented, 

generally, within 24 months of adoption by the IPCB. 

A Level II response would be implemented in the event that a violation of the 8-hour 

ozone NAAQS were to be measured at a monitoring site within the Chicago maintenance 

area. In order to select appropriate corrective measures, Illinois will work with LADCO 

and other Lake Michigan States to conduct a comprehensive study to determine the 
26

causes of the violation and the control measures necessary to mitigate the problem. The 

analysis will examine the following factors:

the number, location, and severity of the ambient ozone concentrations;

the weather patterns contributing to ozone levels;

potential, contributing emissions sources;

the geographic applicability of possible contingency measures;

emissions trends, including timeliness of implementation of scheduled control 

measures;

current and recently identified control technologies;

air quality contributions from outside the maintenance area.

Contingency measures will be selected from those listed in Table 6.1 or from any other 

measure deemed appropriate and effective at the time the selection is made. This list of 

contingency measures is comprehensive, and it is expected that only a few of these 

measures would be required. The selection between measures will be based upon costeffectiveness, emission reduction potential, economic and social considerations, ease and 

timing of implementation, or other appropriate factors. Implementation of necessary 

controls in response to a Level II trigger will take place as expeditiously as possible, but 

in no event later than 18 months after Illinois makes a determination, based on qualityassured ambient data, that a violation of the NAAQS has occurred.

Adoption of additional control measures is subject to necessary administrative and legal 

processes. Illinois EPA will solicit input from all interested and affected persons in the 

area prior to selecting appropriate control measures. No contingency measure will be 

implemented without providing the opportunity for full public participation. This process 

will include publication of notices, an opportunity for public hearing, and other measures 

required by Illinois law.

6.2 Commitment to Revise Plan

As noted in Section 4.5 above, Illinois commits to review its Maintenance Plan eight 

years after redesignation, as required by Section 175(A) of the CAA. The Maintenance 

Plan revision is intended to ensure continued attainment of the 8-hour ozone NAAQS for 

an additional ten-year period.

6.3 Public Participation

In accordance with Section 110(a)(2) of the CAA, Illinois is required to have a public 

comment period and provide the opportunity for a public hearing on the Maintenance 

Plan prior to adoption. Public participation in the SIP process is provided for as follows:

Notice of availability of the Maintenance Plan document and the time and date of 

the public hearing was published in the Chicago Sun Times on July 8, 2011.
27

If requested, the public hearing to receive comments on the Chicago Maintenance 

Plan was scheduled for August 18, 2011, at 1:00 p.m. in the Sangamo Room at 

the Illinois EPA’s Headquarters at 1021 N. Grand Ave. East, Springfield, Illinois.

A 30-day public comment period was also available to receive comments on the 

Maintenance Plan. A summary of the comments received and Illinois EPA’s

responses thereto is included as part of the submittal to U.S. EPA.

6.4 Legal Authority to Implement and Enforce

The Maintenance Plan must contain a demonstration that the State of Illinois has the 

necessary legal authority to implement and enforce the measures relied upon to attain and 

maintain the NAAQS. Illinois has the legal authority to implement and enforce the 

requirements of this SIP submittal pursuant to the Illinois Environmental Protection Act.
28

7.0 CONCLUSIONS

The Chicago nonattainment area has attained the 8-hour ozone NAAQS established in 

1997 and has complied with the applicable provisions of the Clean Air Act required of 

moderate ozone nonattainment areas. Illinois has submitted an attainment demonstration 

that was based on air quality modeling and contains enforceable control measures. 

Illinois has performed an analysis that demonstrates that the Chicago NAA has attained 

the 1997 8-hour ozone NAAQS and believes the air quality improvements are due to 

permanent and enforceable control measures. Supporting documentation is contained 

herein.

Illinois has prepared a Maintenance Plan that meets the requirement of the Clean Air Act. 

This Maintenance Plan provides for the continued attainment of the 1997 8-hour ozone 

NAAQS for a period of ten years after U.S. EPA has formally redesignated the area to 

attainment. This Maintenance Plan provides adequate contingency measures for 

potential, additional emission reductions in the event that future violations of the 8-hour

ozone NAAQS are observed in the area. 

Illinois has prepared a comprehensive emission inventory of the precursors of ozone 

completed for the ―attainment‖ year 2008, and has prepared a projection of the emission 

inventory to a year at least 10 years following redesignation. These projections indicate 

that emissions levels in the Chicago nonattainment area will continue to remain much 

lower than emissions from the attainment year 2008 levels, thereby maintaining the 

ozone NAAQS in future years. Illinois commits to continue to operate an appropriate 

monitoring network to verify the maintenance of the attainment status once the area has 

been redesignated. Illinois EPA has the legal authority to implement and enforce all 

control measures.

Finally, the Maintenance Plan includes on-road motor vehicle emissions budgets for use 

in transportation conformity determinations to assure that any increases in emissions 

from this sector do not jeopardize continued attainment of the 8-hour ozone standard 

during the ten-year maintenance period. This Maintenance Plan has been prepared in 

accordance with the requirements specified in U.S. EPA’s guidance document, and 

additional guidance received from U.S. EPA staff.
29

APPENDIX A

Summary of Ambient Air Monitoring Data 

(2006-2008)
30

Table A.1

2006-2008 8-hour Ozone Design Values 

for Monitors in the Lake Michigan Region

State of Illinois

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Cook 170310001 Alsip 76 78 85 66

Cook 170310032 Chicago (SWFP) 74 75 82 67

Cook 170310064 Chicago (U. of Chicago) 70 70 79 63

Cook 170310072 Chicago (Jardine) 67 65 75 63

Cook 170310076 Chicago (ComED) 73 75 80 66

Cook 170311003 Chicago (Taft) 73 77 79 64

Cook 170311601 Lemont 75 70 85 71

Cook 170314002 Cicero 62 60 68 60

Cook 170314007 Des Plaines 66 65 78 57

Cook 170314201 Northbrook 69 68 76 65

Cook 170317002 Evanston 70 72 80 58

DuPage 170436001 Lisle 63 62 72 57

Kane 170890005 Elgin 66 62 75 61

Lake 170971002 Waukegan 71 71 81 63

Lake 170971007 Zion 72 68 80 69

McHenry 171110001 Cary 65 57 74 65

Will 171971011 Braidwood 66 68 71 60

State of Indiana

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Elkhart 180390007 Bristol 72 67 82 68

Lake 180890022 Gary 73 73 85 62

Lake 180890030 Whiting 77 81 88 62

Lake 180892008 Hammond 73 75 77 68

La Porte 180910005 Michigan City 69 75 73 59

La Porte 180910010 La Porte 70 69 78 65

Porter 181270026 Valparaiso 70 71 80 61

St. Joseph 181410010 Potato Creek St Park 69 69 75 63

St. Joseph 181410015 South Bend 61 58 67 58

St. Joseph 181411007 Granger 73 70 82 69

 
31

State of Michigan

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Allegan 260050003 Holland 86 91 94 73

Benzie 260190003 Frankfort/Benzonia 76 80 82 66

Berrien 260210014 Coloma 78 76 86 73

Cass 260270003 Cassopolis 75 73 83 71

Kalamazoo 260770008 Kalamazoo 73 68 81 70

Kent 260810020 Grand Rapids 77 82 84 66

Kent 260810022 Evans/Oakfield 78 81 85 69

Leelanau 260890001 Peshawbestown 71 73 79 62

Manistee 261010922 Manistee 77 83 83 65

Mason 261050007 Scottville 75 76 83 68

Missaukee 261130001 Houghton Lake 71 73 76 66

Muskegon 261210039 Muskegon 82 90 86 72

Ottawa 261390005 Jenison 79 83 88 67

Schoolcraft 261530001 Seney 75 76 85 64

State of Wisconsin

County AQS Code Site Name Design Value 4th High 2006 4th High 2007 4th High 2008

Brown 550090026 Green Bay 70 66 82 63

Door 550290004 Newport Beach 80 79 92 69

Kenosha 550590019 Chiwaukee 78 79 85 72

Kewaunee 550610002 Kewaunee 75 77 85 65

Manitowoc 550710007 Manitowoc (Two Rivers) 75 78 85 64

Milwaukee 550790010 Milwaukee (16th St.) 63 64 67 60

Milwaukee 550790026 DNR SE Region 68 68 75 63

Milwaukee 550790041 Milwaukee (UWM-North) 72 73 78 65

Milwaukee 550790085 Milwaukee (Bayside) 75 73 83 69

Ozaukee 550890008 Grafton 72 71 82 64

Ozaukee 550890009 Harrington Beach 74 72 84 67

Racine 551010017 Racine 71 71 77 65

Sheboygan 551170006 Sheboygan 82 83 88 75

Walworth 551270005 Lake Geneva 70 72 75 64

Washington 551310009 Slinger 65 66 71 60

Waukesha 551330027 Waukesha 66 67 72 60
32

APPENDIX B

Chicago 8-Hour Ozone Maintenance Plan 

Transportation Conformity

Motor Vehicle Emissions Budget Documentation
33

TRANSPORTATION CONFORMITY

This section describes the development of the Chicago nonattainment area motor vehicle 

emissions budgets associated with the revised Maintenance Plan for the 1997 8-hour 

NAAQS. Average summer weekday motor vehicle emissions budgets are being 

proposed for the attainment year, 2008, and for the Maintenance Plan end year 2025 for 

the ozone precursor pollutants volatile organic material (VOM) and oxides of nitrogen 

(NOx). These budgets were developed consistent with the motor vehicle activity 

assumptions and emissions control strategies incorporated into the Chicago 8-hour ozone 

Attainment Demonstration analysis. The enclosed budgets were developed using the 

inventory method of the United States Environmental Protection Agency’s (U.S.EPA)

MOVES2010 (MOVES) model. The MOVES model incorporates local inputs such as 

annual vehicle miles of travel, vehicle fleet characteristics, meteorological conditions and 

vehicle and fuel emission control programs.

Background

Section 176(c)(4) of the Clean Air Act Amendments of 1990 requires that transportation 

plans, programs, and projects which are funded or approved under Title 23 of the United 

States Code (USC) must be determined to conform with State or Federal air 

implementation plans. A motor vehicle emissions budget is that portion of the total 

allowable emissions allocated to highway and transit vehicle use that are defined in the 

implementation plan for a certain year. Section 93.101 of the rule defines a ―control 

strategy [State] implementation plan revision‖ as a ―plan which contains specific 

strategies for controlling the emissions and reducing ambient levels of pollutants in order 

to satisfy Clean Air Act (CAA) requirements of reasonable further progress and 

attainment.‖ In order to demonstrate conformity to the motor vehicle emissions budget, 

emissions from the implementation of a transportation plan or a transportation 

improvement program (TIP) must be less than or equal to the budget level (40 CFR § 

93.118(a)).

Transportation conformity will be determined based on these proposed on-road motor 

vehicle emissions budgets after the U.S. Environmental Protection Agency (U.S. EPA) 

determines that the budgets meet the adequacy criteria of the transportation conformity 

rule under §93.118(e). The motor vehicle emissions budgets in this submittal are 

adequate as each of the six criteria under §93.118(e) is satisfied. These six criteria 

include:

1. The submitted control strategy implementation plan revision or Maintenance Plan 

was endorsed by the Governor (or his or her designee) and was subject to a State 

public hearing.

2. Before the control strategy implementation plan or Maintenance Plan was submitted 

to U.S. EPA, consultation among federal, State, and local agencies occurred; full 

implementation plan documentation was provided to U.S. EPA; and U.S. EPA’s 

stated concerns, if any, were addressed;
34

3. The motor vehicle emissions budgets(s) is clearly identified and precisely quantified;

4. The motor vehicle emissions budget(s), when considered together with all other 

emissions sources, is consistent with all applicable requirements for reasonable 

further progress, attainment, or maintenance (whichever is relevant to the given 

implementation plan submission);

5. The motor vehicle emissions budget(s) is consistent with and clearly related to the 

emissions inventory and the control measures in the submitted control strategy 

implementation plan revision or Maintenance Plan, and

6. Revisions to previously submitted control strategy implementation plans explain and 

document any changes to previously submitted budgets and control measures, 

impacts on point and area source emissions; any changes to established safety 

margins; and reasons for the changes (including the basis for any changes related to 

emissions factors or estimates of vehicle miles traveled).

This State Implementation Plan (SIP) and the associated motor vehicle emissions budgets 

have been developed by the Illinois Environmental Protection Agency (Illinois EPA), the 

designated air quality agency for the State of Illinois. The required public hearing to 

accept public comment on the proposed Maintenance Plan and associated motor vehicle 

emissions inventory was held on December 16, 2008 in Room 9-031 of the James R. 

Thompson Center in downtown Chicago. Notification of this hearing was printed in the

Chicago Sun Times on November 15, 2008. Comments on the proposed attainment 

demonstration and motor vehicle emissions budgets were accepted for 30 days after the 

public hearing. A ―Responsiveness Summary‖ which addresses the written comments 

received was prepared and is included in the final submission. 

Regarding this revision to the Chicago 8-Hour Ozone Maintenance Plan, notice of a 

comment 30-day comment period was posted on the Illinois EPA’s website and printed in 

the Chicago Sun Times on July 8, 2011. A public hearing to discuss the revised 

Maintenance Plan and associated motor vehicle emissions budgets was to be held on 

August 18, 2011, if it was requested. Comments were required to be postmarked by 

August 8, 2011, unless a public hearing was requested. No request for a public hearing 

was received. All comments were addressed in the attached Responsiveness Summary. 

None of the comments affected the proposed motor vehicle emissions budgets.

In compliance with criterion #2 above, a Tier 2 Conformity Consultation Team meeting 

was held on January 30, 2009 to discuss the proposed Maintenance Plan and associated 

motor vehicle emissions budgets. The Consultation Team includes representatives from 

the Federal Highway Administration, Federal Transit Authority, U.S. EPA, Chicago 

Metropolitan Agency for Planning (CMAP), Illinois Department of Transportation 

(IDOT), Regional Transportation Authority, and the Illinois EPA. In addition, the 

development of the Maintenance Plan was discussed at length by the LADCO Project 

Team, which includes a representative from the U.S. EPA Region V office. The draft 
35

Maintenance Plan was also forwarded to the Region V representative for his review and 

comment. A follow-up meeting of the Tier 2 Conformity Consultation Team to discuss 

the revised MOVES-based motor vehicle emissions budgets was held at the CMAP on 

June 28, 2011.

The motor vehicle emissions budgets proposed and described herein were, in compliance 

with adequacy criterion #5, developed consistent with the methodology and control 

strategy assumptions used in the Chicago 1997 8-hour Ozone Attainment Demonstration 

and associated Reasonable Further Progress (RFP) plan. The effects of these controls are 

incorporated into the emissions estimates produced by the MOVES model. In response 

to adequacy criteria #4 and #6, the narrative of the Chicago 8-hour Ozone Maintenance 

Plan discusses the emissions estimates from other sectors and any changes in regulations. 

Following, in response to adequacy criteria #3, is a discussion of the inputs and 

assumptions incorporated into the development of the proposed Maintenance Plan motor 

vehicle emissions budgets.

Vehicle Miles Travelled: The attainment year 2008 motor vehicle emissions estimates 

contained Chicago 8-hour ozone Maintenance Plan incorporate county-and townshiplevel 2008 annual vehicle miles traveled (VMT) levels from the Illinois Department of 

Transportation (IDOT). The 2008 annual VMT total for the 6-county-3-township 

Chicago NAA was approximately 58.8 billion miles. For future year emission estimates, 

VMT was grown to the target year at a compound growth rate of 1.5% per year. 

Applying this growth factor to the 2008 VMT level yields future year annual VMT 

projections of 65.2 billion for 2015, 70.3 billion for 2020, and 75.7 billion for 2025.

Meteorological Data: U.S. EPA guidance for the use of the MOVES model 

requires the use of representative local temperature and absolute humidity data. Average 

2008 maximum and minimum monthly temperatures for the region were obtained from 

the National Weather Service local climatological data (LCD) for O’Hare International 

Airport. Absolute humidities corresponding to the average temperatures were calculated 

from LCD information as well. These 2008 temperatures and absolute humidity values, 

shown below, were used in the year 2025 emissions modeling.

Motor Vehicle Emissions Controls: Beyond the U.S. EPA’s federal motor vehicle 

Month Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec

Min, (oF) 15 16 27 39 45 61 64 64 57 47 32 14

Max, (oF) 32 30 43 60 66 81 84 82 75 62 46 32

Month Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec

AH, grains/lb 17 14 21 34 41 73 83 74 71 39 25 15

2008 Minimum and Maximum Temperatures for Chicago, from O'Hare NWS Data

2008 Absolute Humidity Corresponding to the Temperatures Above
36

control program emissions standards, the primary local motor vehicle emissions control 

programs that were in place in the Chicago NAA in 2008, and are projected to still be 

required in 2025 are a vehicle inspection and maintenance (I/M) program and the 

required use of reformulated gasoline (RFG).

Inspection and Maintenance (I/M): The Illinois I/M program in effect since 

2007 requires biennial On-Board Diagnostics II (OBD) testing on all model year (MY) 

1996 and newer (MY96+) light-duty gasoline vehicles (cars and light-duty trucks), and 

biennial exhaust idle and gas cap testing on MY96+ heavy duty gasoline vehicles 

including gasoline-powered buses, registered in the I/M testable area. Motorcycles and 

diesel vehicles are not subject to I/M. The program includes a 4-year grace period for 

new vehicles. This post-2007 I/M program was established when the Illinois legislature 

amended the Illinois Vehicle Inspection law in 2005 to (a) end dynamometer testing of 

vehicles, (b) require an OBD-based program beginning in February 2007, and (c) remove 

the requirement for testing compliant pre-MY96 vehicles. 

The Chicago I/M program vehicle testing domain includes the urbanized areas in the 

Chicago NAA. An ―I/M Coverage‖ percentage was developed based on the amount of 

VMT from vehicles subject to the inspection program compared to total area VMT. The 

I/M Coverage percentage for the Chicago 8-hour ozone NAA is 91.5%. 

Fuels: The use of federal RFG has been required in the Chicago NAA since 

1995. The 8-hour ozone Attainment Demonstration and original Maintenance Plan 

assumed the use of northern grade RFG in 2008 and beyond. RFG was and is assumed to 

contain 10% ethanol. The MOVES model can account for other fuels, such as E85, 

natural gas, methanol, etc, but for all practical purposes the gallons of such alternative 

fuels and hence the number of vehicles using them is very small compared to the number 

of gasoline and diesel vehicles, therefore, the use of such fuels was not considered.

Gasoline Sulfur: The federal Tier 2 regulations require gasoline sulfur levels to 

average no greater than 30 parts per million (ppm) with a maximum of 80 ppm 

beginning in 2007. There are no Illinois gasoline sulfur requirements, therefore, 

the MOVES default gasoline sulfur levels were used in the emissions modeling. 

Diesel Sulfur: The federal Tier 2 regulations limit the level of sulfur in diesel 

fuel requiring on- highway diesel fuel to 15 ppm beginning in 2006. There are no 

Illinois diesel sulfur requirements, therefore, the MOVES default diesel sulfur 

levels were used in the emissions modeling. 

Fuel Volatility: The volatility of summer RFG, measured as Reid vapor pressure 

(RVP), is not specifically regulated. However, a fuels’ RVP is one of the primary 

characteristics controlled by refiners in order to meet the RFG performance 

standards. The MOVES model contains default RVP levels for different seasons 

of the year based on fuel compliance testing. Therefore, the MOVES default 

RVP levels were used in the emissions modeling. 
37

Vehicle Registration Distribution: A Chicago area-specific vehicle registration 

distribution (RD) profile based upon 2008 information data was developed by Illinois 

EPA’s Division of Mobile Source Programs from vehicle age data for 2008 provided by 

the Illinois Secretary of State’s Department of Motor Vehicles. The RD is the fraction of 

vehicles of a given vehicle type and age in the fleet of vehicles of that type as a whole. 

Different vehicle types have different RDs Chicago-area RDs generally show fewer 

older vehicles than the nationwide average or default, because vehicles in the Chicago 

area tend to wear out faster than they do in the rest of the country due to rust from road 

salt and heavy city driving. 

Source Type Population represents the number of vehicles of each MOVES vehicle type 

in the fleet as a whole within the area under consideration. Accurate local source-type 

populations were not available; therefore the MOVES default fractions modified by 

VMTs by vehicle type were used.

VMT Temporal Fractions are the VMT fractions of annual VMT by month of the year, 

of weekly VMT by day of the week, and daily VMT by hour of the day. The Illinois 

EPA uses temporal fractions derived from data collected from continuous count stations 

and presented by IDOT. Temporal fractions vary by road type.

Speed distributions are the fractions of VMT on a given road type by given vehicle 

types in various speed ranges (bins). Thus, on a typical Urban Arterial, a small fraction 

of the vehicles are traveling at less than 10 mph (plus or minus 5 mph), more at 20 mph, 

more at 30mph, most at 40 mph, less at 50 mph, and so on. These fractions differ by 

hour of the day—in more congested conditions during rush hours, the maximum fraction 

might be in the 30 mph range rather than the 40 mph range. MOVES uses speed 

distributions when aggregating emissions (or emission rates) for vehicles at different 

speeds. The Illinois EPA used the speed distributions derived from the CMAP 

transportation demand model.

Ramp fraction is the fraction of total VMT on limited-access highways such as 

Interstates that is from on- and off-ramps to or from those highways. Driving on limitedaccess highways is more or less at uniform speed, but driving on ramps involves 

considerable acceleration and deceleration; and these speed changes affect emissions. 

The default MOVES Ramp Fractions are 15% on Rural Interstates, 10% on Urban 

Interstates, and 2% on Other Freeways and Expressways. Illinois does not have actual or 

observed Ramp Fraction data; therefore the MOVES default values were used.

Road Type Distribution is the (fraction of) VMT on different road categories within an 

area under consideration. The Illinois EPA uses VMT data by HPMS functional class 

(FC) published by IDOT as the basis of its emission calculations. The Road Type 

Distribution for Rural Interstates in a county is the county’s Rural Interstate VMT 

divided by the county’s total all-road-type VMT. Similar calculations can be made for 

MOVES road types and vehicle types.
38

Safety Margin 

The U.S. EPA’s transportation conformity regulations allow for the use of a safety 

margin in the development of motor vehicle emissions budgets for Maintenance Plans. A 

Safety Margin is defined as ―the amount by which the total projected emissions from all 

sources of a given pollutant are less than the total emissions that would satisfy the 

applicable requirement for reasonable further progress, attainment, or maintenance.‖ 

According to table 4.6, VOM and NOx emissions for the end of the maintenance plan 

year 2025 are 175.60 and 469.65 tons per day, respectively, less than the year 2008 

attainment year levels. As year 2025 emissions levels are projected to be substantially 

less than the attainment year 2008 emissions, a 15% safety margin is being proposed to 

be added to the 2025 estimated motor vehicle emissions to make up the motor vehicle 

emissions budget. The 15% increase would equate to an increase of 6.28 tpd of VOM 

and 16.34 tpd of NOx. 

Motor Vehicle Emissions Budgets

Using the emissions generated by the MOVES model inventory methodology and 

incorporating the additional emissions from the Maintenance Plan safety margin, 

following are the proposed attainment year 2008 and Maintenance Plan end year 2025

Chicago 8-hour ozone motor vehicle emissions budgets for use in determining 

transportation conformity. 

Proposed Chicago 8-hour Ozone Maintenance Plan

2008 and 2025

Motor Vehicle Emissions Budgets

(tons per ozone season weekday)

Estimated Emissions Safety Margin Motor Vehicle 

Emissions Budgets

Year VOM NOx VOM NOx VOM NOx

2008 117.23 373.52 - - - - 117.23 373.52

2025 41.85 108.93 6.28 16.34 48.13 125.27
Law Office of Robert Ukeiley

435R Chestnut Street, Suite 1 0 Berea, Kentucky 40403 0 teI.859-986-5402 0 fax.866-618-1017

Robert Ukeiley

rukeiley@igc.org

Darin Schroeder

darin@airadvocafes.net

VIA NEXT DAY MAIL - RETURN RECEIPT REQUESTED

August 8, 2011

Dean Studer, Hearing Officer

Illinois EPA

1021 North Grand Avenue, East

P,O. Box 19276

Springfield, Illinois 62794-9276

telephone number: 217/558-8280

RE: Comments on State Implementation Plan (SIP) Submittals for the

Chicago and Metro-East Ozone Nonattainment Areas and the

Chicago PM2.5 Nonattainment Area

Dear Hearing Officer Studer:

On behalf of my client, Sierra Club, and their thousands of members who are

adversely impacted from air pollution from the Chicago and Metro-East

Nonattainment areas, I am writing to submit comments on Illinois EPA's draft

Maintenance Plans for the Chicago and Metro-East Nonattainment Areas for the

1997 ozone National Ambient Air Quality Standard (NAAQS) and the Chicago

Nonattainment Area for the 1997 particulate matter less than 2.5 microns (PM2.5)

NAAQS. We appreciate the opportunity to comment on these Plans to make sure

they are as strong as possible as ozone and PM2.5 have a variety of very serious

adverse impacts including triggering asthma attacks and causing premature

mortality.

I. INTRODUCTION

The Illinois Environmental Protection Agency lIEPA) is holding a public

comment period on three maintenance plans: (1) The Metro-East Plan for the 1997

ozone NAAQS, (2) the Chicago Plan for the 1997 ozone NAAQS and; (3) the Chicago
Hearing Officer Studer

August 8, 2011

Page 2

Plan for the 1997 PM2.5 NAAQS. These maintenance plans are a required part of

IEPA's attempt to have these nonattainment areas re-designated to attainment.

42 U.s.c. § 7407(d)(3)(E)(iv).

There are several flaws in these maintenance plans which are described

below. The most serious is that the Chicago and Metro-East SIPs may not be

currently adequate to maintain compliance with the ozone NAAQS.

IEPA should remedy these flaws in order to better protect the public

from the harmful effects of PM2.5 and ozone. PM2.5 is "produced chiefly by

combustion processes and by atmospheric reactions of various gaseous

pollutants," thus "[ s]ources of fine particles include ... motor vehicles,

power generation, combustion sources at industrial facilities, and residential

fuel burning." 71 Fed. Reg. 61,144, 61,146 (Oct. 17,2006). The effects of

PM2.5 on humans are profound. For example, short-term exposure to PM2.5

is associated with "premature mortality, hospital admissions or emergency

department visits for respiratory disease, and effects on lung function and

symptoms." 71 Fed. Reg. 2619,2627 Uan. 17,2006). Furthermore, PM2.5

adversely affects our natural surroundings. Regional haze is caused in part

by particulates in the air scattering sunlight. EPA, Haze- How Air Pollution

Affects the View (available at

http://www.epa.gov/ttn/oarpg/tl/fr notices/haze.pdf).

Ozone, often referred to as smog, has numerous harmful effects on

human respiratory systems which include inducing asthma attacks and

aggravating chronic lung diseases like emphysema and bronchitis. EPA,

Smog-Who Does it Hurt?, 2-3 (available at

http://www.epa.gov/air/ozonepollution/pdfs/smog.pdf). Long-term exposure

may result in the permanent scarring of lung tissue. EPA, Ozone and Your

Health, U.S. Environmental Protection Agency (available at

http://www.epa.gov/air/ozonepollution/pdfs/health.pdf). Ozone can be

particularly harmful to adolescents, as exposure to ozone can also lead to

"chronic, adverse effects on lung development in children from the age of 10

to 18 years...." See Gauderman, W. James, et aI., The Effect ofAirPollution

on Lung Development from 10 to 18 Years ofAge, N. Engl. J. Med. 351:11, at

1057 (Sept. 9, 2004). However, the greatest harm "may occur later in life,

since reduced lung function is a strong risk factor for complications and

death during adulthood." lei. at 1063.

II. ANALYSIS

A. CHICAGO OZONE MAINTENANCE PLAN

The most fundamental flaw with the Chicago ozone maintenance plan

is that it may not be adequate to maintain the NAAQS. According to the US
Hearing Officer Studer

August 8, 2011

Page 3

EPA, for the 2008-2010 period: "One or more sites in this area has violated

the NAAQS prior to 2008-2010 and does not have a valid 2008-2010 design

value." Ex. 1 at ftnt 4. Thus, IEPA cannot prove that its current SIP is

maintaining the 1997 ozone NAAQS in the Chicago nonattainment area.

Therefore, IEPA cannot say that the current SIP will maintain the NAAQS in

the future.

In addition, Clean Air Act Section 110(1) prohibits the US EPA for

approving any SIP revision that may interfere with another NAAQS. 42 U.S.c.

§ 7410(1). However, IEPA has presented no analysis at all to establish that

re-designating Chicago from nonattainment to attainment and the

implementing the maintenance plan will not interfere with the 2008 ozone

NAAQS of 75 ppb or the 2010 I-hour nitrogen dioxide NAAQS. Without this

analysis, US EPA will not be able to approve these proposed SIP changes.

According to IEPA, several monitors in the Chicago nonattainment area

monitored violations in 2006-2008 of the 2008 75 ppb NAAQS. See Chicago

Maintenance Plan at 12. Thus, the Clean Air Act 110(1) analysis is even more

critical.

IEPA claims that the 2006-2008 ozone design value was the result of

permanent and enforceable emission limits. Maintenance Plan for the Illinois

Portion of the Chicago Ozone Nonattainment Area for the 1997 8-Hour Ozone

Standard (Revised) ("Chicago Ozone Maintenance Plan") at 5. This

statement is not correct. Much of the emission reductions that influenced

the 2006-2008 design value were from the NOx SIP Call and later reductions

were from the Clean Air Interstate Rule (CAIR). See Chicago Ozone

Maintenance Plan at 15, 19. Emissions reductions from the NOx SIP Call and

CAIR are not permanent and enforceable because the NOx SIP Call and CAIR

are cap and trade programs which means sources can decrease and increase

their emissions on a yearly basis and because the NOx SIP Call is no longer in

place and CAIR has been vacated by the US Court of Appeals for the U.S.

Court of Appeals for the District of Columbia Circuit. IEPA presents no

analysis of whether emission reductions from the Cross State Air Pollution

Rule will have the same effect on ambient ozone levels as the NOx SIP Call

and CAIR. In addition, the Cross State Air Pollution Rule also allows some

trading so its emission reductions cannot be considered permanent.

Another flaw is that IEPA's future emission projections fails to consider

US EPA's recent announcement that it is repealing the vapor capture

requirements for gas stations. US EPA has been clear that this will increase

emissions because not all cars have on-board capture systems.

IEPA's projection of future emissions are based on an unsupported claim that

on-road NOx will decrease dramatically. This ignores the reality that vehicle

standards allow larger vehicles to emit more NOx in terms of mass emissions.
Hearing Officer Studer

August 8, 2011

Page 4

Thus, IEPA's reliance on vehicle turnover is not supported by evidence which

justifies the claimed reduction in mass NOx emissions. Furthermore, IEPA's

emission calculations from on-road mobile sources fail to consider US EPA's recent

decision to allow 15% ethanol in all gas. See Chicago Ozone Maintenance Plan at

36. This increased use of ethanol at levels for which many cars and light trucks,

and particularly their pollution control devices, were not designed to deal with will

increase NOx and VOC emissions. IEPA does not account for this increase.

IEPA acknowledges that ambient monitoring data must be available to

the pUblic. US EPA no longer makes ambient monitoring data available to

the public on its web page. IEPA claim to the contrary on page 13 is simply

no longer true. See http://www.epa.gov/air/data/monvals.html?st-IL-lilinois

(no data after 2008).

The Chicago Ozone Maintenance Plan also fails to consider climate

change. "A maintenance plan must take into account the sort of things, such

as population growth and changes to the industrial base, that might cause

existing pollution-control measures to become inadequate in the future even

if they served well in the past." Sierra Club v. EPA, 375 F.3d 537 (7'h cir.

2004). Climate change is just the sort of thing that might cause existing

pollution-control measures to become inadequate in the future even if they

served well in the past.

US EPA has admitted that weather influences ozone formation. See 72

Fed. Reg. 44781; 72 Fed. Reg. 44778, 44779. Climate change, which we are

indisputably experiencing, means that weather patterns in the future are

going to be more conducive to ozone formation than weather patterns in the

past. US EPA is well aware of this issue. US EPA has recently stated:

The report, "Assessment of the Impacts of Global Change on Regional

U.s. Air Quality: A Synthesis of Climate Change Impacts on GroundLevel Ozone," concludes that there is a potential for climate change to

make ozone pollution worse in some regions and that future ozone

management decisions may need to account for the possible impacts

of climate change.

EPA News Brief, April 17, 2009, Climate Change Impacts on Regional Air

Quality Report Just Released by EPA. The Report is entitled: U.s. EPA.

Assessment of the Impacts of Global Change on Regional U.S. Air Quality: A

Synthesis of Climate Change Impacts on Ground-Level Ozone (An Interim

Report of the U.S. EPA Global Change Research Program). U.s.

Environmental Protection Agency, Washington, DC,

EPA/600/R-07/094F, 2009. This report is available at

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=203459 and is

incorporated herein by reference.
Hearing Officer Studer

August 8, 2011

Page 5

US EPA's Report further found:

These climate-induced increases, averaged over the summer season,

were in the range of approximately 2-8 parts per billion (ppb) for

Maximum Daily 8-hour Average 03 concentration, a key metric for

regulating U.S. air quality. The climate sensitivity of 03 was greatest

for the peak pollution episodes that tend to occur over a number of

days each summer, resulting in substantially larger increases for these

times than for the overall seasonal average.

Id. at xix.

US EPA went on to find:

A subset of results also suggests that climate change effects on 03

grow continuously over time, with evidence for significant impacts (in

the same direction as described above) emerging as early as the

2020s. For example, the Columbia research group (which simulated

only the eastern half of the United States) found significant

summertime 03 increases across broad swathes of the Midwest and

Mid-Atlantic by the 2020s, with greater increases by the 2050s and

2080s.

Id. at xxiv (emphasis added).

Also, relevant, EPA stated:

Air quality managers may also need to plan to extend the season over

which they monitor 03 concentrations and be prepared to issue air

quality alerts earlier in the spring and later into the fall.

Id. at xxv. The proposed Chicago Ozone Maintenance Plan does not propose

such an extension of the monitoring season.

Furthermore, an EPA-funded study by Knowlton and colleagues1

utilized the Goddard Institute for Space Studies (GISS) Global Climate Model,

in combination with the Penn State/National Center for Atmospheric

Research Mesoscale Model 5, and the Community Multiscale Air Quality

(CMAQ) model to simulate climate-induced changes in ozone levels for the

1 Knowlton K. Rosenthal JE. Hogrefe C. Lynn B. Gaffin S. Goldberg R. Rosenzweig. Civerolo K.

Ku J-Y. Kinney PL. 2004. Assessing ozone-related health impacts under a changing climate.

Environ Health Perspect 112:1557-1563. doi:1O.1289/ehp.7163 available via

http://dx.doLorg/
Hearing Officer Studer

August 8, 20II

Page 6

purposes of conducting a health impact analysis. This study demonstrates

the feasibility of integrating global and regional climate models with

models that are typically used by air quality managers for the purposes of

evaluating compliance with air quality standards. IEPA has not done this.

A study of the New York metropolitan region found a 4.5% increase in

summertime ozone-related premature deaths in 2050 relative to the 1990s.2

A second study projected increased ozone smog concentrations in suburban

counties downwind of New York City, demonstrating the potential of climate

change to spread adverse health effects well beyond the city limits. 3 A third

study detailed climate change effects on future ozone levels in 50 eastern US

cities, projecting a 68% increase in the number of days exceeding the 8-hour

03 standard and increases in mortality and respiratory disease hospital

admissions.' The Jacobson 2008 report also directly links increases in carbon

dioxide to increased mortality, hospitalization, asthma and cancer rates.

These studies are integral to a meaningful assessment of the impacts of

climate change on ozone. Yet with regard to the Chicago Ozone

Maintenance Plan, there has been no consideration of climate changes

impacts on ozone, either as to formation or as to consequences.

Failure to consider this important aspect of the problem would lead to an

arbitrary result. Therefore, we request that IEPA re-evaluate the

Maintenance Plan in light of the increasing danger climate change will cause

from ozone.

IEPA also provides for alternative measures which are not permissible under

the Clean Air Act. The Maintenance Plan states: "Illinois EPA commits to keep

these measures in effect after redesignation, or to provide equivalent emissions

levels using alternate measures." Chicago Ozone Maintenance Plan at 18.

However, the Clean Air Act does not allow for alternative measures.

Finally, IEPA states: "The control measures identified in the RFP document,

including those listed above, will result in a 15.7 percent reduction in VOM

emissions from 2002 emissions levels by the year 2008." Chicago Ozone

Maintenance Plan at 20. Now that year 2008 has passed, IEPA must prove that

these reductions were actually achieved.

2 Knowlton K. et al(2004).

3 Kinney P, Rosenthal j, Rosenzweig C, Hogrefe C, Solecki W, Knowlton K, Small C, Lynn B,

Civerolo K, Ku j, Goldberg R, Oliveri C. 2006. Assessing potentiai public health impacts of

changing climate and land uses: the New York Climate and Health Project. In: Regional

Climate Change and Variability: Impacts and Responses (Ruth M, Donaghy K, Kirshen P,

eds.). Cheltenham(UK):Edward Elgar, 161-189.

, jacobson (2008). jacobson, MZ. 2008. On the casual link between carbon dioxide and air

pollution mortality. Geophysical Research Letters. 3S: L03809.
Hearing Officer Studer

August 8, 2011

Page 7

B. METRO-EAST ST. LOUIS OZONE MAINTENANCE PLAN

Like the Chicago Ozone Maintenance Plan, the most fundamental flaw

with the Metro-East ozone maintenance plan is that it may not be adequate

to maintain the NMQS. According to the US EPA, for the 2008-2010 period,

"[ olne or more sites in this area has violated the NMQS prior to 2008-2010

and does not have a valid 2008-2010 design value." Ex. 1 at ftnt 4. Thus,

IEPA cannot prove that its current SIP is maintaining the 1997 ozone NMQS

in the Metro-East nonattainment area. Therefore, IEPA cannot say that the

current SIP will maintain the NMQS in the future.

In addition, Clean Air Act Section 110(1) prohibits the US EPA for

approving: any SIP revision that may interfere with another NMQS. 42 U.s.c.

§ 7410(1). However, IEPA has presented no analysis at all to establish that

re-designating Metro-East from nonattainment to attainment and the

maintenance plan will not interfere with the 2008 ozone NMQS of 75 ppb or

the 2010 I-hour nitrogen dioxide NMQS. Without this analysis, US EPA will

not be able to approve these proposed SIP changes. According to IEPA,

several monitors in the Metro-East nonattainment area monitored violations

in 2007-2009 of the 2008 75 ppb NMQS. See Metro-East Ozone

Maintenance Plan at 12. Thus, the Clean Air Act 110(1) analysis is even more

critical.

IEPA claims that the 2006-2008 ozone design value was the result of

permanent and enforceable emission limits. Metro-East Ozone Maintenance

Plan at 5. This statement is not correct. Much of the emission reductions

that influenced the 2006-2008 design value were from the NOx SIP Call and

later reductions were from the Clean Air Interstate Rule (CAIR). See MetroEast Ozone Maintenance Plan at 19. Emissions reductions from the NOx SIP

Call and CAIR are not permanent and enforceable because the NOx SIP Call

and CAIR are cap and trade programs which means sources can decrease

and increase their emissions on a yearly basis and because the NOx SIP Call

is no longer in place and CAIR has been vacated by the US Court of Appeals

for the DC Circuit. IEPA presents no analysis of whether emission reductions

from the Cross State Air Pollution Rule will have the same effect. In addition,

this new rule also allows some trading so its emission reductions cannot be

considered permanent.

IEPA's emission projections appear to be inaccurate. There is no

indication that the emission projections considered emissions from Prairie

State Generating Station which should be in operation, and thus pOlluting,

prior to 2015.

The Metro-East Ozone Maintenance Plan suffers from many of the

defects described above in Section II.A regarding the Chicago Ozone
Hearing Officer Studer

August 8, 2011

Page 8

Maintenance Plan. These include: (1) failing to consider increased emissions

from US EPA's repealing the vapor capture requirements for gas stations and

allowing up to 15% ethanol in gasoline; (2) assuming that vehicle turn over

will reduce mass on-road emissions even though purchasing larger new

vehicles can offset this; (3) failing to make ambient monitoring data

available to the public; (4) failing to consider climate change impacts on

future ambient ozone levels; (5) relying on unidentified alternate measures

with no legal authority to do so. We will not repeat the detailed explanation

of these flaws provided above but for the reasons provided above IEPA must

fix these defects.

C. CHICAGO PM2.5 MAINTENANCE PLAN

Similar to the ozone maintenance plans, IEPA claims that the Chicago

2007-2009 PM2.5 design value was the result of permanent and enforceable

emission limits. Maintenance Plan for the Chicago Nonattainment Area for

the 1997 PM2.5 National Ambient Air Quality Standard (Revised) ("Chicago

PM2.5 Maintenance Plan") at 5. This statement is not correct. Much of the

emission reductions that influenced the 2007-2009 design value were from

the NOx SIP Call and later reductions were from the Clean Air Interstate Rule

(CAIR). See Chicago PM2.5 Maintenance Plan at 15. Emissions reductions

from the NOx SIP Call and CAIR are not permanent and enforceable because

the NOx SIP Call and CAIR are cap and trade programs which means sources

can decrease and increase their emissions on a yearly basis and because the

NOx SIP Call is no longer in place and CAIR has been vacated by the US Court

of Appeals for the DC Circuit. IEPA presents no analysis of whether emission

reductions from the Cross State Air Pollution Rule will have the same effect.

In addition, this new rule also allows some trading so its emission reductions

cannot be considered permanent.

The Chicago PM2.5 Maintenance Plan also suffers from many of the

defects described above in Section II.A regarding the Chicago Ozone

Maintenance Plan. These include: (1) failing to consider increased emissions

from US EPA's repealing the vapor capture requirements for gas stations and

allowing up to 15% ethanol in gasoline; (2) assuming that vehicle turn over

will reduce mass on-road emissions even though purchasing larger new

vehicles can offset this; and (3) failing to make ambient monitoring data

available to the public. We will not repeat the detailed explanation of these

flaws provided above but for the reasons provided above IEPA must fix these

defects.

III. CONCLUSION

It is imperative from a public health and welfare point of view that IEPA

correct the above flaws in its maintenance plans. If you have any questions
Hearing Officer Studer

August 8, 2011

Page 9

about these comments, please do not hesitate to contact me. Otherwise, we

look forward to IEPA improving its maintenance plans to ensure the health

and welfare of millions of Illinois inhabitants.

Sincerely,

Robert Ukeiley

Counsel for Sierra Club
, .

EXHIBIT 1
Table1

Table 1. Design Values in Areas Previously Designated Nonattainment for the 1997 8-Hour Ozone NAAQS

AQS Data Query: 6/27/2011 Last Updated: 7/12/2011

2008-2010 8·

Hour Ozone Clean Data

EPA Designation Design Value Determination Redesignation Designated Area Region(s) Status' Classilication' (ppm)'~ MetNAAQS? Date Date Albany.Schenectady-Troy, NY 02 Nonattainment Former Subpart 1 0.072 Ves 3/2512008 Allegan Co, MI OS Maintenance Former Subpart I 0.074 Ves 9/2512010 9/2412010 Allentown-Bethlehem-Easton,

Altoona,

PA 03 Maintenance Fonner Subpart 1 0.076 Ves 3/4/2008 PA 03 Maintenance Former Subpart 1 0.070 Ves 8/1/2007 Amador & Calaveras Cos (Central Mtn), CA 09 Nonattainment Former Subpart 1 0,083 Ves Atlanta, GA 04 Nonattainment Subpart 2IModerate 0.080 see footnote 4 Baltimore. MD 03 Nonanainment Subpart 2/Moderate 0.089 No Baton Rouge, LA 06 Nonattainment Subpart 2/Moderate 0.078 Ves 10112/2010 Beaumont-Port Arthur, TX 06 Maintenance Subpart 2/Moderate 0.074 Ves 10120/2010 Benton Harbor, MI

Benzie

05 Maintenance Former Subpart I 0.071 Ves 511 6/2007 Co, MJ 05 Maintenance Former Subpart I 0.069 Ves 5/1612007 Berkeley & Jefferson Cos. WV 03 ' Attainment Fonner EAC 0.070 Ves Birmingham, AL 04 Maintenance Former Subpart 1 0.075 Ves 5/12/2006 Boston-Lawrence-Worcester (E. Mass), MA 01 Nonattainment Subpart 2/Moderate 0.075 Ves 4/18/2011 Boston-Manchester-Portsmouth (SE), NH 01 Nonattainment Subpart 2/Moderate 0.069 Ves Buffalo-Niagara Falls, NY 02 Nonanainment Former Subpart } 0.071 Ves 1/612010 Canton-Massillon, OH OS Maintenance Fonner Subpart I 0.073 see footnote 4 5/16/2007 CassCo, MI 05 Maintenance Subpart 2/Marginal 0.070 Ves 5/16/2007 Charleston, WV 03 Maintenance Fonner Subpart I 0.069 Ves 7/1112006 Charlone-Gastonia-Rock Hill, NC-SC 04 Nonattainment Subpart 2/Moderate 0.082 Ves Chattanooga, TN-GA 04 Attainment Former EAC 0.075 Ves Chicago-Gary-Lake County, IL-IN 05 Nonattainment Subpart 2/Moderate 0.074 see footnote 4 4/1212010 Chico,CA 09 Nonattainment Former Subpart 1 0.079 Ves Cincinnati-Hamilton, OH·KY-IN 05,04 Maintenance Fonner Subpart I 0.079 Ves 5/11/2010 5/11/2010 Clarkesville-Hopkinsville, TN-KY 04 Maintenance Fonner Subpart 1 0.069 Ves 1125/2006 Clearfield & Indiana Cos, PA 03 Maintenance Former Subpart 1 0.074 Ves 3/1912009 Cleveland-Akron-Lorain, OH OS Maintenance Subpart 2/Moderate 0.077 Ves 9/15/2009 9/1512009 Columbia, SC 04 Attainment FonnerEAC 0.070 Ves Columbus,

Dallas-Fort

OH

Worth,

05 Maintenance Former Subpart I 0.077 Ves 9/1512009 9/1512009 TX 06 Nonattainment Subpart 2/Serious 0.086 No Dayton-Springfield, OH 05 Maintenance Former Subpart 1 0.075 see footnote 4 8/1312007 Denver-Boulder-Greeley-Ft Collins-Loveland, CO 08 Nonattainment Former Subpart 1 0.077 Ves Detroit-Ann Arbor, Ml

Door Co, WI

05 Maintenance Subpart 2iMarginal 0.075 Ves 6/29/2009 6/29/2009

Erie,

OS Maintenance Fonner Subpart I 0.073 Ves 7/1212010 7/1212010 PA 03 Maintenance Former Subpart I 0.072 Ves 10/912007 Essex Co (Whiteface Mtn), NY 02 Nonattainment Former Subpart 1 0.072 see footnote 4 1/612010 Evansville, IN OS Maintenance Fonner Subpart 1 0.070 Ves 12129/2005 Fayetteville, NC 04 Attainment FormerEAC 0.071 Ves

Page 1
Table1

Flint, Ml 05 Maintenance Fonner Subpart

I 0.068 Yes 511612007 Fort Wayne, IN 05 Maintenance Former Subpart I 0.067 Yes 1/1112007 Franklin Co, PA 03 Maintenance Fonner Subpart I 0.067 Yes 712512007 Frederick Co, VA 03 Attainment Former EAC 0.068 Yes Fredericksburg, VA 03 Maintenance Subpart 2IModerate 0.070 Yes 1212312005 Grand Rapids, MI 05 Maintenance Fonner Subpart I 0.069 Yes 5/1612007 Greater Connecticut. CT 01 Nonattainment Subpart 2IModerate 0.078 see footnote 4 913012010

Greene

Greene Co, IN 05 Maintenance Former Subpart

1 0.071 Yes 11/14/2005 Co, PA 03 Maintenance Former Subpart 1 0.072 Yes 311912009 Greensboro-Winston Salem-High Point, NC 04 Attainment Former EAC 0.076 Yes Greenville-Spartanburg-Anderson, SC 04 Attainment Fonner EAC 0.076 Yes Hancock, Knox, Lincoln & Waldo Cos, ME 01 Maintenance Former Subpart J 0.074 Yes 12/1112006 Harrisburg-Lebanon-earlisle, PA 03 Maintenance Former Subpart ) 0.073 Yes 7125/2007 Haywood and Swain Cos (Great Smoky NP), NC 04 Maintenance Former Subpart I 0,072 Yes 121712009 Hickory-Morganton-Lenoir, NC 04 Attainment Former EAC 0.070 Yes Houston-Galveston-Brazoria, TX 06 Nonattainment Subpart 2/Severe 15 0,084 see footnote 4 Huntington-Ashland,

Huron

WV.KY 03,04 Maintenance Former Subpart

I 0.070 Yes 813/2007 Co, MI 05 Maintenance Former Subpart I 0,067 Yes 5116/2007 Imperial Co, CA 09 Nonattainment Subpart 2IModerate 0.078 Yes 1/412010 Indianapolis, IN 05 Maintenance Fonner Subpart I 0.073 Yes 10/1912007 Jackson Co, IN 05 Maintenance Former Subpart I 0,067 Yes 1111412005 Jamestown, NY 02 Nonattainment Fonner Subpart I 0,077 Yes 1/612010 Jefferson Co, NY 02 Nonattainment Subpart 2IModerate 0,072 Yes 3/25/2008 Johnson City-Kingsport-Bristol, TN 04 Attainment Former EAC 0,071 Yes Johnstown, PA 03 Maintenance Former Subpart 1 0.067 Yes 8/112007 Kalamazoo-Battle Creek, Ml 05 Maintenance Former Subpart 1 0,069 Yes 5/16/2007 Kent & Queen Anne's Cos, MO 03 Maintenance Subpart 2/Marginal 0.075 Yes 12122/2006 Kern Co (Eastern Kern), CA 09 Nonattainment Former SubpaJ11 0.083 Yes Kewaunee Co, WI 05 Maintenance Former Subpart I 0,071 Yes 5121/2008 Knoxville, TN 04 Maintenance Former Subpart 1 0,077 see footnote 4 10/1212010 31812011 La Porte, IN 05 Maintenance Subpart 2/Marginal 0,065 Yes 7/19/2007 Lancaster, PA 03 Maintenance Subpart 2/Marginal 0,077 Yes 7/6/2007 Lansing·East Lansing, MI 05 Maintenance Former Subpart I 0.068 Yes 5/1612007 Las Vegas, NV 09 Nonattainment Fonner Subpart I 0,076 Yes 5/3112011 Lima,OH 05 Maintenance Former Subpart I 0,070 Yes 5/16/2007 Los Angeles South Coast Air Basin, CA 09 Nonattainment Subpart 2IExtreme 0,112 No Los Angeles·San Bernardino Cos (W. Mojave), CA 09 Nonattainment Subpart 21Severe 15 0,099 No

Macon,GA

Louisville, KY-IN 04,05 Maintenance FOrmer Subpart

1 0.075 Yes 7/19/2007 04 Maintenance Fonner Subpart 1 0,073 Yes 9/1912007

Manitowoc

Madison& Page Cos (Shenandoah NP), VA 03 Maintenance Former Subpart

I 0,073 Yes 1/312006 Co, WI 05 Maintenance Former Subpart I 0,073 Yes 7/1212010 7/1212010 Mariposa & Tuolumne Cos (Southern Min), CA 09 Nonattainment Former Subpart I 0.083 Yes MasonCo,MJ

Memphis,

05 Maintenance Fonner Subpart

I 0,068 Yes 5/1612007 TN-AR 04,06 Maintenance Subpart 2IModerate 0,076 Yes 3/24/2010 Milwaukee·Racine, WI 05 Nonattainment Subpart 2IModerate 0,074 see footnote 4 3/3112011 Muncie, IN 05 Maintenance Fonner Subpart I 0.065 Yes 11/16/2005 Murray Co (Chattahoochee NFl, GA 04 Maintenance Former Subpart I 0,073 Yes 10/1612007

Page2
Table1

Muskegon, MI 05 Maintenance Subpart 2/Marginal 0.074 Ves 5/16/2007 Nashville, TN 04 Attainment FormerEAC 0.076 Ves Nevada Co (Western part), CA 09 Nonattainment Former Subpart I 0.084 Yes New York-No New Jersey-Long Island, NY-NJ-CT 02,01 Nonattainment Subpart 2/Moderate 0.084 see footnote 4 Norfolk-Virginia Beach-Newport News (HR). VA 03 Maintenance Subpart 2/Marginal 0.072 Yes 611/2007 Parkersburg-Marietta. WV-OH 03,05 Maintenance Fonner Subpart I 0.073 Yes 5/1612007 Philadelphia.Wilmington-Allantic CiIy, PA-NJ-MD-DE 03,02 Nonattainment Subpart 2/Moderate 0.083 see footnote 4 Phoenix-Mesa, AZ 09 Nonattainment Former Subpart I 0.077 Ves PittSburgh-Beaver Valley, PA 03 Nonattainment Former Subpart I 0.081 Ves Portland, ME 01 Maintenance Subpart 2/Marginal 0.072 Ves 12/11/2006 Poughkeepsie, NY 02 Nonattainment Subpart 2/Moderate 0.D75 Yes 116/2010 Providence (all ofRI), Rl 01 Nonattainment Subpart 2/Moderate 0.076 Ves 11122/2010 Raleigh-Durham-Chapel Hill, NC 04 Maintenance Fonner Subpart I 0.074 see footnote 4 12126/2007 Reading, PA 03 Maintenance Former Subpart I 0.079 Ves 8/24/2007 Richmond.Petersburg, VA 03 Maintenance Subpart 2/Marginal 0.076 Ves 6/112007 Riverside Co (Coachella Valley), CA 09 Nonattainment Subpart 2/Severe 15 0.095 No Roanoke, VA 03 Attainment Former EAC 0.069 Ves Rochester, NY 02 Nonattainment Former Subpart I 0.069 Ves 3/2512008 Rocky Mount, NC 04 Maintenance Fonner Subpart 1 0.071 Yes 11I6/2006 Sacramento Metro, CA 09 Nonattainment Subpart 2/Severe 15 0.102 No San Antonio, TX 06 Attainment Former EAC 0.D75 Ves San Diego, CA 09 Nonattainment Former Subpart 1 0.088 No San Francisco Bay Area, CA 09 Nonattainment Subpart 2/Marginal 0.080 Ves San Joaquin Valley, CA 09 Nonattainment Subpart 2/Extreme 0.104 No Scranton-Wilkes-Barre, PA 03 Maintenance Former Subpart 1 0.072 Yes 11/1912007 Sheboygan, WI 05 Nonattainment Subpart 2/Moderate 0.D78 see footnote 4 3/31/2011 South Bend-Elkhart, IN 05 Maintenance Fonner Subpart 1 0.064 Ves 7/19/2007 Springfield (W. Mass), MA 01 Nonattainment Subpart 2/Moderate 0.077 see footnote 4

SI. Louis, MO-IL 07,05 Nonattainment Subpart 2/Moderate 0.077 see footnote

4 7111/2011 State College, PA 03 Maintenance Fonner Subpart 1 0.070 Yes 11/1412007 Steubenville-Weirton,OH-WV 05,03 Maintenance Former Subpart 1 0.073 Yes 5/1612007 Sutter Co (Sutter Buttes), CA 09 Nonattainment Former Subpart 1 0.076 Ves Terre Haute. IN 05 Maintenance Former Subpart I 0.063 Yes 1/5/2006 Tioga Co, PA 03 Maintenance Former Subpart I 0.070 Ves 7/612007 Toledo,OH 05 Maintenance Former Subpart 1 0.072 Ves 8/9/2007 Ventura Co, CA 09 Nonattainment Subpart 2/Serious 0.086 No

Washington Co (Hagerstown), MD 03 Attainment Former EAC 0.072 Ves

Washington, DC·MD·VA 03 Nonattainment Subpart 2/Moderate 0.081 see footnote

4

Wheeling, WV-OH 03,05 Maintenance Former Subpart

I 0.073 Ves 511612007 Vork, PA 03 Maintenance Former Subpart I 0.074 Yes 1/14/2008 Youngstown-Warren-Sharon, PA-QH 05,03 Maintenance Former Subpart I 0.074 Yes 10/19/2007

Notes:

1_ Area classification and designation status as of April 27. 2011

Page3
Table1

2. The level of the 1997 8Rhour ozone NAAQS Is 0.08 parts per million (ppm). The design value is the 3-year average of the annual fourth-highest dally

maximum 8Rhour ozone concentration.

3. The design values shown here are computed for the latest design value period using Federal Reference Method or equivalent data reported by

State, Tribal, and Local monitoring agencies to EPA's Air Quality System (AQS) as of May 9, 2011. Concentrations flagged by State, Tribal, or Local

monitoring agencies as having been affected by an exceptional event (e.g., wildfire, volcanic eruption) and concurred by the associated EPA Regional

Office are not included in these calculations.

4. One or more sites In this area has violated the NAAQS prior to 2008·2010 and does not have a valid 2008·2010 design val ue. Although a 2008·2010

design value Is shown, this design value may not represent the worst 2008-2010 air quality in the area. Consequently, we have not used it to Indicate

''Yes'' or "No" in the "Met NAAQS?" column.

Page 4
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1

ILLINOIS ENVIRONMENTAL PROTECTION AGENCY

BUREAU OF AIR

Responsiveness Summary for

Public Questions and Comments on the 

State Implementation Plan Submittals for the

Chicago 8-Hour Ozone Nonattainment Area,

the Chicago PM2.5 Nonattainment Area, and the 

Metro-East 8-Hour Ozone Nonattainment Area

September 16, 2011
2
3

INTRODUCTION

The Illinois Environmental Protection Agency (Illinois EPA) has prepared Maintenance Plans 

for the Chicago and Metro-East ozone nonattainment areas (NAA). The Maintenance Plans are 

required before the areas can be redesignated from nonattainment to attainment of the 8-hour 

ozone National Ambient Air Quality Standard (NAAQS) promulgated by the U.S. 

Environmental Protection Agency (U.S. EPA) in 1997. Similarly, the Illinois EPA has prepared 

a Maintenance Plan for the Chicago NAA, as required before the areas can be redesignated from 

nonattainment to attainment of the annual NAAQS for fine particulates (PM2.5) promulgated by 

the U.S. EPA in 1997. The Illinois EPA intends to submit requests to the U.S. EPA to 

redesignate the Chicago NAA to attainment for both ozone and PM2.5, and to redesignate the 

Metro-East NAA to attainment for ozone in conjunction with the submittal of these Maintenance 

Plans.

The Maintenance Plans provide for the continued attainment of the 1997 ozone NAAQS for the 

Chicago and Metro-East NAAs, and for the continued attainment of the annual PM2.5 NAAQS 

for the Chicago NAA for a period of at least ten years after U.S. EPA has formally redesignated 

the areas to attainment. The Plans also provide assurances that even if a subsequent violation of 

the NAAQS occurs, provisions in the Plan will prevent any future occurrences through the 

enactment of contingency measures that would be triggered upon such occurrence.

PUBLIC HEARING AND COMMENT PERIOD

On July 8, 2011, the Illinois EPA had the Notice of Public Comment Period for State 

Implementation Plan Submittals for the Chicago and Metro-East ozone NAAs and the Chicago 

PM2.5 NAA published in the Chicago Sun Times and in the Illinois edition of the St. Louis Post 

Dispatch. Provision was also given in the notice for a public hearing to be held on August 18, 

2011, conditioned on the receipt of a timely request for Public Hearing. Since there were no 

requests for a public hearing, the public hearing originally scheduled for August 18, 2011 was 

cancelled. The Illinois EP A posted a notice of Cancellation of the Public Hearing on its website 

on August 12, 2011. As indicated in the Notice of Public Comment, the public comment period 

began on July 8, 2011 and closed on August 8, 2011. 

COMMENTS AND RESPONSES BY THE ILLINOIS EPA

A commenter suggested that the Chicago ozone maintenance plan may not be adequate to 

maintain the NAAQS, noting that U.S. EPA’s Air Quality System (AQS) contains the following 

footnote for the 2008-2010 period for the Chicago NAA: “One or more sites in this area has 

violated the NAAQS prior to 2008-2010 and does not have a valid 2008-2010 design value.” 

The footnote in the cited AQS report occurs when one or more monitors in the NAA do not 

meet the completeness criteria established by U.S. EPA. For the 2008-2010 period, design 

values are not shown in AQS for two monitoring stations in the Chicago area, prompting 

the footnote cited by the commenter. The two sites are located at Wacker and Adams
4

Streets in downtown Chicago (site ID: 17-031-0042) and 750 Dundee Road in Northbrook 

(site ID: 17-031-4201). The monitor at Wacker and Adams is located on the 90th floor of 

the Willis Tower (Sears Tower) and is operated as a special purpose monitor during the 

summer months (typically June, July, and August). As a special purpose monitor, the 

measurements are not used for the purpose of determining the areas attainment status. At 

Northbrook, the Illinois EPA has historically operated two instruments to measure ozone 

at the same location. The data from the two instruments are distinguished in AQS by POC 

(Parameter Occurrence Code) Codes 1 and 2. One of the instruments located at 

Northbrook (POC 2) was an experimental open path analyzer that was difficult and 

expensive to maintain, and routinely reported lower ozone values than the co-located 

instrument. The experimental analyzer was discontinued in 2009. The other instrument 

operated at this location is the Federal Reference Method (FRM) ozone monitor (POC 1). 

It has operated normally during 2008-2010, meeting U.S. EPA’s completeness criteria, and 

for which a valid design value for 2008-2010 has been calculated. U.S. EPA confirmed the 

validity and completeness of ozone measurements, and that all monitoring sites in the 

Chicago nonattainment area have three years of data showing attainment of the 1997 ozone 

NAAQS by publishing the Clean Data Determination on April 12, 2011.

A commenter pointed out that: “Clean Air Act (CAA) Section 110(l) prohibits the U.S. EPA 

from approving any SIP revision that may interfere with another NAAQS. 42 U.S.C. § 7410(I). 

However, Illinois EPA has presented no analysis at all to establish that re-designating Chicago 

from nonattainment to attainment and that implementing the maintenance plan will not interfere 

with the 2008 ozone NAAQS of 75 ppb or the 2010 1-hour nitrogen dioxide NAAQS.” 

The Illinois EPA does not agree that a further analysis of the effects of redesignation on 

another NAAQS is required or that U.S. EPA cannot approve the SIP revision without 

such analysis. The Illinois EPA has prepared the Chicago ozone Maintenance Plan 

consistent with U.S. EPA’s published guidance. The document adequately demonstrates

that the 1997 NAAQS for ozone has been attained in the Chicago NAA based on three 

consecutive years of ambient air monitoring data. The plan contains emission estimates of 

the precursors of ozone for the “attainment year” and multiple “projection years” that 

demonstrate that the projected level of emissions is sufficient to maintain the NAAQS. In 

fact, the emissions projections indicate that ozone precursor emissions will decrease 

substantially in future years, ensuring continued attainment and maintenance of the 

NAAQS. The Maintenance Plan provides commitments to maintain and enforce the 

control measures that are already in place, to continue monitoring air quality in the NAAs, 

to prepare periodic updates of the emissions inventories, and to implement contingency 

measures, if needed, to correct future exceedances of the NAAQS. Based on these 

commitments, there is no basis to conclude that approval of the Maintenance Plan will 

cause backsliding of the air pollution control programs that have allowed the NAAs to 

reach attainment with the ozone NAAQS. As Illinois’ Maintenance Plan has been prepared 

in accordance with the requirements specified in U.S. EPA’s guidance document and 

additional guidance received from U.S. EPA staff, the plan is approvable as a SIP revision. 

Further, U.S. EPA has not implemented the 2008 ozone NAAQS, and has decided not to 

tighten the standard before 2013. Should U.S. EPA decide to implement the 2008 ozone 
5

standard, or to revise it in the future, Illinois is obligated to address the new ozone NAAQS, 

independent of efforts to redesignate existing NAAs to attainment with the old standard. 

With regard to the 2010 NO2 NAAQS, all ambient monitors in Illinois, including the

Chicago area, are meeting the standard and the Illinois EPA has recommended that all 

counties in Illinois be designated as attainment. U.S. EPA has not yet acted on Illinois’ 

recommendation. As shown in the Maintenance Plan, NOx emissions (a combination of 

compounds that includes NO2) are expected to decrease significantly in future years, so 

there is no basis to conclude that re-designating the Chicago NAA from nonattainment to 

attainment for the ozone NAAQS, and implementing the ozone maintenance plan will 

interfere with attainment or maintenance of the 2010 1-hour NO2 NAAQS. 

A commenter questioned whether air quality improvements were the result of permanent and 

enforceable emission reductions since the NOx SIP Call and CAIR are cap and trade programs, 

and because the NOx SIP Call is no longer in place and CAIR has been vacated by the U.S.

Court of Appeals. 

Illinois EPA agrees that regional emission reductions provided by the NOx SIP Call and 

CAIR yielded significant air quality improvements, and that these programs combined 

with other emission reduction measures helped the Chicago area to meet the 8-hour ozone 

NAAQS. The Illinois EPA does not agree, however, that these measures are not permanent 

and enforceable. Illinois submitted, and U.S. EPA approved, SIP revisions addressing the 

requirements of the NOx SIP Call, and, subsequently, the CAIR program. Beginning in 

2009, the CAIR program maintained the same emissions budgets as the NOx SIP Call 

program it replaced. In its decision to vacate the CAIR, the U.S Court of Appeals 

determined that the CAIR emissions budgets should remain in place, until U.S. EPA 

remedied the identified deficiencies. U.S. EPA recently promulgated the Cross-State Air

Pollution Rule (CSAPR) to address the Court’s concerns. Significantly, the CSAPR

requires that states meet emissions budgets that are more stringent than CAIR, and 

provides new requirements that ensure that emission reductions are achieved within each 

affected state.

A commenter noted that Illinois EPA’s future emission projections did not consider U.S. EPA’s 

recent announcement that it is repealing the vapor capture requirements for gas stations. 

Regarding the Stage II program, on July 15, 2011 the U.S. EPA issued a proposed rule 

determining that June 30, 2013 will be the date when the “widespread use” of onboard 

refueling vapor recovery (ORVR)-equipped vehicles will occur. At this point the U.S. EPA

expects “ORVR alone to achieve emissions reductions equal to Stage II alone” so no 

additional emissions would result from the cessation of the Stage II program. The 

widespread use determination would not obligate states to remove any existing Stage II 

vapor recovery requirements and the Chicago 8-hour ozone Maintenance Plan does not 

propose to end the Stage II program. If at a later date, the Illinois EPA should wish to end 

the Stage II program in Chicago, a revision to the State Implementation Plan (SIP) would 
6

have to be adopted and approved by the U.S.EPA demonstrating that no additional 

refueling emissions would result. As Stage II is not required in the Metro-East St. Louis 

area, U.S. EPA’s widespread use determination would have no impact on either regional 

air quality or the Metro-East St. Louis 8-hour ozone Maintenance Plan.

A commenter stated that Illinois EPA’s projection of future emissions decreases from on-road 

motor vehicles is unsupported, and that its emissions calculations from on-road mobile sources 

fail to consider U.S. EPA’s recent decision to allow 15% ethanol in all gas. 

Illinois EPA used the U.S. EPA’s new MOVES2010 model to estimate motor vehicle 

emissions in both the Chicago and Metro-East St. Louis areas. This model incorporates 

emissions factors for all vehicle category types. The model also incorporates local motor 

vehicle registration data and national fleet turnover rate statistics. The reduction in 

estimated NOx emissions results from the introduction of new vehicles complying with the 

Tier 2 motor vehicle emissions standards and the retirement of older vehicles. The Tier 2 

program, phased in beginning in 2004, established more stringent NOx emissions standards

on cars, trucks, and sport utility vehicles. Given the implementation of these significantly 

more stringent emission standards, the estimated reduction in motor vehicle NOx emissions 

is reasonable. 

Regarding the comment regarding the U.S.EPA’s recent decision to allow the blending of 

up to 15% ethanol into conventional gasoline, the use of such fuel is limited to flexiblefueled vehicles and model year (MY) 2001 light-duty cars and trucks, and medium-duty 

passenger vehicles. In its “Notice of Decision Granting a Partial Waiver” (76 FR 4662), the 

U.S.EPA stated that Department of Energy (DOE) testing of MY 2001-2006 light duty 

motor vehicles “strongly supports a determination that E15 will not cause or contribute to 

MY2001-2006 light-duty motor vehicles exceeding their applicable exhaust emission 

standards.” The U.S.EPA further states that “MY 2001-2006 light duty motor vehicles 

should generally be able to meet evaporative emission standards when operated on E15 so 

long as the fuel does not exceed a RVP of 9.0 psi (pounds per square inch)in the 

summertime volatility control season.” The U.S.EPA goes on to state: “...in fact, such 

vehicles should have somewhat lower evaporative emissions when operated on 9.0 psi E15 

than when operated on currently available in-use fuel.”

Regarding MY 2007 and newer vehicles, in its November 4, 2010 “Notice of Partial Waiver 

Decision” (75 FR 68094) the U.S. EPA states that DOE Catalyst Study and other 

information before EPA adequately demonstrates that the impact of E15 on overall 

emissions, including both immediate and durability related emissions, will not cause or 

contribute to violations of the emissions standards for these motor vehicle. Likewise, the 

data and information adequately show that E15 will not lead to violations of the 

evaporative emissions standards, so long as the fuel does not exceed a Reid Vapor Pressure 

(RVP) of 9.0 psi in the summertime control season.” 

The use of reformulated gasoline (RFG) is required in both the Chicago and Metro-East St. 

Louis areas. The summertime volatility of these fuels are in the range of 7.0 psi, well below 

the 9.0 psi level referenced by the U.S.EPA. Based on these statements from the U.S.EPA, 
7

the Illinois EPA believes that the use of E15 gasoline blends will not result in any increase 

in emissions in the ozone control season.

A commenter questioned whether ambient monitoring data is available to the public, since U.S. 

EPA and the Illinois EPA apparently do not have timely data available no their respective web 

pages. 

The Illinois EPA submits all ambient monitoring data it collects to U.S. EPA’s Technology 

Transfer System (TTN) Air Quality System (AQS). The AQS Data Mart is a database 

containing all of the information from the AQS system and is available free of charge to the 

public. The AQS Data Mart is available on the internet at:

http://www.epa.gov/ttn/airs/aqsdatamart

U.S. EPA also maintains the following web sites to disseminate air quality data to the 

public:

AirData @ http://www.epa.gov/air/data/index.html

AirExplorer @ http://www.epa.gov/airexplorer/

AirNow @ http://www.airnow.gov/

A commenter pointed out that Chicago Ozone Maintenance Plan failed to consider climate 

change, noting that climate change might cause existing pollution-control measures to become 

inadequate in the future.

The Illinois EPA understands that there is a clear relationship between meteorological 

conditions and ground level ozone levels, and that climate change may affect the frequency 

and severity of ozone-conducive meteorological conditions in future years. Although 

climate change is not directly addressed in the Maintenance Plan, nor is it required to be

addressed, the Maintenance Plan provides contingency measures that will be triggered in 

the event of future NAAQS violations. The Illinois EPA has committed to maintain an 

adequate monitoring network in the Chicago area and to take corrective actions in the 

event of future NAAQS violations, whether caused by normal year-to-year meteorological 

variability, climate induced adverse conditions, or emissions changes that were not 

anticipated in the development of the Maintenance Plan. The Illinois EPA has also 

committed to revise the plan within the next ten years to ensure maintenance of the 

NAAQS.

A commenter stated that the Clean Air Act does not allow for alternative measures in the event 

that current control measures now in effect must be replaced with equivalent emission reduction 

measures.

Illinois EPA does not agree with the commenter’s statement. Section 110(l) of the CAA 

provides for revisions of the SIP as long as the plan does not interfere with attainment or 

reasonable further progress, or other applicable requirements. To be clear, Illinois’ 
8

Maintenance Plan does not rely on alternate measures. In fact, the plan clearly states 

Illinois’ commitment to keep existing control measures in place after the Chicago NAA has 

been redesignated to attainment. In the event that future revisions of Illinois’ SIP become 

necessary, the Maintenance Plan commits the state to provide equivalent emissions levels 

using alternate control measures. Such revisions are subject to review and approval by 

U.S. EPA. 

A commenter noted that the summary of Illinois’ Reasonable Further Progress demonstration 

contained in the Chicago 8-hour ozone Maintenance Plan states: “The control measures 

identified in the RFP document ... will result in a 15.7 percent reduction in VOM emissions 

from 2002 emissions levels by the year 2008.” The commenter requested that Illinois EPA must 

prove that these reductions were actually achieved. 

The Illinois EPA does not agree that such a demonstration is required for the Maintenance 

Plan, since there is no such requirement in any guidance published to date by U.S. EPA. 

Further, U.S. EPA has published a Clean Data Determination for the 1997 8-hour ozone 

NAAQS for the Chicago NAA (April 12, 2011), which waives CAA planning requirements, 

including RFP, as long as the nonattainment area continues to meet the NAAQS. However, 

based on this comment, the Illinois EPA has revised the 2002 VOM emission estimates 

contained in the Maintenance Plan (Table 4.2 on page 15). The VOM emission estimates in 

the draft Maintenance Plan for 2002 did not properly account for changes in U.S. EPA’s 

emissions estimation guidance that occurred subsequent to preparation of the 2002 

inventory. U.S. EPA’s guidance for computing emissions from certain area source 

categories, most significantly for graphic arts, consumer solvents, architectural coatings, 

and industrial coatings, changed between 2002 and 2008. Illinois EPA’s 2008 emissions 

estimates were performed using the revised methodology, but the 2002 estimates contained 

in the draft document were based on the earlier methodology. The final document has 

been revised to apply a consistent methodology for all years. Comparing VOM emissions 

in the Chicago NAA from 2002 to 2008 indicates that VOM emissions decreased 

significantly during that period, about 210 tons per day. This amount equates to a 

reduction of about 21%, which exceeds the amount needed to demonstrate RFP. 

Metro-East St. Louis Ozone Maintenance Plan

A commenter suggested that the Metro-East ozone maintenance plan may not be adequate to 

maintain the NAAQS, noting that U.S. EPA’s Air Quality System (AQS) contains the following 

footnote for the 2008-2010 period for the St. Louis NAA: “One or more sites in this area has 

violated the NAAQS prior to 2008-2010 and does not have a valid 2008-2010 design value.” 

The footnote in the cited AQS report occurs when one or more monitors in the NAA do not 

meet the completeness criteria established by U.S. EPA. For the 2008-2010 period, design 

values are not shown in AQS for two monitoring stations (three samplers at two locations) 

in the St. Louis area, prompting the footnote cited by the commenter. The two sites are 

located at 4520 Margaretta in St. Louis, MO (site ID: 29-510-0086) and 4580 South 

Lindbergh in Sunset Hills, MO (site ID: 29-189-004). The Missouri Department of Natural 

Resources (MDNR) discontinued these monitoring stations prior to the 2009 ozone season. 
9

These monitors were determined by MDNR and U.S. EPA – Region 7 to be redundant with 

other monitors in the metropolitan area, and did not measure the highest levels of ozone in 

the NAA during the years that they operated at those locations. U.S. EPA requires that 

changes in a state’s monitoring network be identified and approved in advance, and 

contained in the state’s monitoring network plan. MDNR’s 2009 network plan properly 

and timely identified and justified the need to discontinue these sites. By approving the 

changes to MDNR’s monitoring network plan, U.S. EPA determined that the revised 

network was still adequate to characterize ozone air quality in the St. Louis NAA.

A commenter pointed out that: “Clean Air Act (CAA) Section 110(l) prohibits the U.S. EPA 

from approving any SIP revision that may interfere with another NAAQS. 42 U.S.C. § 7410(I). 

However, Illinois EPA has presented no analysis at all to establish that re-designating Metro-East 

from nonattainment to attainment and that implementing the maintenance plan will not interfere 

with the 2008 ozone NAAQS of 75 ppb or the 2010 1-hour nitrogen dioxide NAAQS.” 

The Illinois EPA does not agree that a further analysis of the effects of redesignation on 

another NAAQS is required or that U.S. EPA cannot approve the SIP revision without 

such analysis. The Illinois EPA has prepared the Metro-East ozone Maintenance Plan 

consistent with U.S. EPA’s published guidance. The document adequately demonstrates

that the 1997 NAAQS for ozone has been attained in the St. Louis NAA based on three 

consecutive years of ambient air monitoring data. The plan contains emission estimates of 

the precursors of ozone for the “attainment year” and multiple “projection years” that 

demonstrate that the projected level of emissions is sufficient to maintain the NAAQS. In 

fact, the emissions projections indicate that ozone precursor emissions will decrease 

substantially in future years, ensuring continued attainment and maintenance of the 

NAAQS. The Maintenance Plan provides commitments to maintain and enforce the 

control measures that are already in place, to continue monitoring air quality in the NAAs, 

to prepare periodic updates of the emissions inventories, and to implement contingency 

measures, if needed, to correct future exceedances of the NAAQS. Based on these 

commitments, there is no basis to conclude that approval of the Maintenance Plan will 

cause backsliding of the air pollution control programs that have allowed the NAAs to 

reach attainment with the ozone NAAQS. As Illinois’ Maintenance Plan has been prepared 

in accordance with the requirements specified in U.S. EPA’s guidance document and 

additional guidance received from U.S. EPA staff, the plan is approvable as a SIP revision. 

Further, U.S. EPA has not implemented the 2008 ozone NAAQS, and has decided not to 

tighten the standard before 2013. Should U.S. EPA decide to implement the 2008 ozone 

standard, or to revise it in the future, Illinois is obligated to address the new ozone NAAQS, 

independent of efforts to redesignate existing NAAs to attainment with the old standard. 

With regard to the 2010 NO2 NAAQS, all ambient monitors in Illinois, including the 

Metro-East area, are meeting the standard and the Illinois EPA has recommended that all 

counties in Illinois be designated as attainment. U.S. EPA has not yet acted on Illinois’ 

recommendation. As shown in the Maintenance Plan, NOx emissions (a combination of 

compounds that includes NO2) are expected to decrease significantly in future years, so 

there is no basis to conclude that re-designating the Metro-East NAA from nonattainment 
10

to attainment of the ozone NAAQS, and implementing the maintenance plan will interfere 

with the 2010 1-hour nitrogen dioxide NAAQS. 

A commenter questioned whether air quality improvements in the Metro-East area were the 

result of permanent and enforceable emission reductions since the NOx SIP Call and CAIR are 

cap and trade programs, and because the NOx SIP Call is no longer in place and CAIR has been 

vacated by the U.S. Court of Appeals. 

The Illinois EPA believes that these comments have been addressed in its previous 

responses for the Chicago ozone nonattainment area.

A commenter pointed out that Illinois EPA’s emission projections do not account for emissions 

from the Prairie State Generating Station which should be in operation, and thus polluting, prior 

to 2015.

The Prairie State Generating Station is located in Washington County, Illinois and is 

expected to be in operation by 2012. As required, Illinois EPA’s emissions projections 

include only those emissions occurring or projected to occur within the boundaries of the 

nonattainment area, which includes Madison, Monroe, St. Clair, and Jersey counties in 

Illinois. The Illinois EPA acknowledges that the Prairie State Generating Station is located 

in close proximity to the Metro-East ozone nonattainment area and emissions from it will 

cause air quality impacts within the NAA. Before issuing a PSD permit to Prairie State, the 

Illinois EPA required the company to address its potential impact on the St. Louis ozone 

nonattainment area. Prairie State adequately demonstrated that future emissions from the 

facility will not interfere with the area’s ability to attain and maintain the NAAQS. 

A commenter identified the same “defects” in the Metro-East Ozone Maintenance Plan identified 

previously in comments on the Chicago Ozone Maintenance Plan, including: (1) failing to 

consider increased emissions from U.S. EPA’s repealing the vapor capture requirements for gas 

stations and allowing up to 15% ethanol in gasoline; (2) assuming that vehicle turn over will 

reduce mass on-road emissions even though purchasing larger new vehicles can offset this; (3) 

failing to make ambient monitoring data available to the public; (4) failing to consider climate 

change impacts on future ambient ozone levels; (5) relying on unidentified alternate measures 

with no legal authority to do so. 

The Illinois EPA believes that these comments have been addressed in its previous 

responses for the Chicago ozone nonattainment area.

A commenter questioned whether PM2.5 air quality improvements in Chicago were the result of 

permanent and enforceable emission reductions since the NOx SIP Call and CAIR are cap and 

trade programs, and because the NOx SIP Call is no longer in place and CAIR has been vacated 

by the U.S. Court of Appeals. 
11

The Illinois EPA believes that this comment has been addressed in its previous responses 

for the Chicago ozone nonattainment area.

A commenter identified the same “defects” in the Chicago PM2.5 Maintenance Plan identified 

previously in comments on the Chicago Ozone Maintenance Plan, including: (1) failing to 

consider increased emission from U.S. EPA’s repealing the vapor capture requirements for gas 

stations and allowing up to 15% ethanol in gasoline; (2) assuming that vehicle turn over will 

reduce mass on-road emissions even though purchasing larger new vehicles offset this; and (3) 

failing to make ambient monitoring data available to the public. 

The Illinois EPA believes that these comments have been addressed in its previous 

responses for the Chicago ozone nonattainment area.