2010-30840. Approval and Promulgation of Air Quality Implementation Plans; Illinois

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed Rule.

SUMMARY:

EPA is proposing to approve a July 29, 2010, request from the State of Illinois to exempt sources of Nitrogen Oxides (NO_X) in the Illinois portions of the Chicago-Gary-Lake County, Illinois-Indiana and St. Louis, Missouri-Illinois 8-hour ozone nonattainment areas from Clean Air Act (CAA) requirements for NO_X Reasonably Available Control Technology (RACT) for purposes of attaining the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS). The State's NO_X RACT waiver request is based on the most recent three years of complete, quality-assured ozone monitoring data, which demonstrate that additional reduction of NO_X emissions in the ozone nonattainment areas would not contribute to attainment of the 1997 8-hour ozone NAAQS in the two ozone nonattainment areas. In addition to waiving the NO_X RACT requirement for the State of Illinois, final approval of the NO_X RACT waiver would also suspend a requirement for EPA to promulgate a NO_X RACT Federal Implementation Plan (FIP) for the 8-hour ozone nonattainment areas.

DATES:

Comments must be received on or before January 7, 2011.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R05-OAR-2010-0671, by one of the following methods:

• http://www.regulations.gov: Follow the on-line instructions for submitting comments.
• E-mail: [e-mail].
• Fax: [phone].
• Mail: John M. Mooney, Chief, Attainment Planning and Maintenance Section, Air Programs Branch, (AR-18J), U.S. Environmental Protection Agency, 77 West Jackson Boulevard, Chicago, Illinois 60604.
• Hand Delivery: John M. Mooney, Chief, Attainment Planning and Maintenance Section, Air Programs Branch, (AR-18J), U.S. Environmental Protection Agency, 77 West Jackson Boulevard, 18th Floor, Chicago, Illinois 60604. Such deliveries are only accepted during the Regional Office's normal hours of operation, and special arrangements should be made for deliveries of boxed information. The Regional Office official hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m., excluding Federal holidays.

Instructions: Direct your comments to Docket ID No. EPA-R05-OAR-2010-0671. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at http://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through http://www.regulations.gov, your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects and viruses. For additional instructions on submitting comments, go to section I of the SUPPLEMENTARY INFORMATION section of this document.

Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at the U.S. Environmental Protection Agency, Region 5, Air and Radiation Division, 77 West Jackson Boulevard, Chicago, Illinois 60604. This facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays. We recommend that you telephone Edward Doty at [phone] before visiting the Region 5 office.

FOR FURTHER INFORMATION CONTACT:

Edward Doty, Environmental Scientist, Attainment Planning and Maintenance Section, Air Programs Branch (AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, [phone].

SUPPLEMENTARY INFORMATION:

Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. This SUPPLEMENTARY INFORMATION section is arranged as follows:

I. What should I consider as I prepare my comments for EPA?

II. What is the background for this action?

III. State Petition

IV. EPA Review of the Petition

A. Have the ozone nonattainment areas attained the 1997 8-hour ozone NAAQS?

B. EPA's analysis of Illinois' NO_X RACT Waiver Petition

V. What are the environmental effects of this action?

VI. EPA's Proposed Action

VII. Statutory and Executive Order Reviews

I. What should I consider as I prepare my comments for EPA?

When submitting comments, remember to:

1. Identify the rulemaking by docket number and other identifying information (subject heading, Federal Register date, and page number).

2. Follow directions—EPA may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

3. Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

4. Describe any assumptions and provide any technical information and/or data you used.

5. If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

6. Provide specific examples to illustrate your concerns, and suggest alternatives.

7. Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

8. Make sure to submit your comments by the comment period deadline identified in the proposed rule.

II. What is the background for this action?

EPA has determined that ground-level ozone (O₃) is detrimental to human health. On July 18, 1997 (62 FR 38856), EPA promulgated an 8-hour ozone NAAQS of 0.08 parts per million parts of air (ppm). The standard is violated in an area when any ozone monitor in the area (or in its downwind environs) records 8-hour ozone concentrations with a 3-year average of the annual fourth-highest daily maximum 8-hour ozone concentrations equaling or exceeding 0.085 ppm.

Section 107 of the CAA required EPA to designate as nonattainment any area that violated the 1997 8-hour ozone standard. The 8-hour ozone designations and classifications were promulgated on April 30, 2004 (69 FR 23857). In that EPA rulemaking, the Chicago-Gary-Lake County, Illinois-Indiana (IL-IN) and St. Louis, Missouri-Illinois (MO-IL) areas were designated as nonattainment for the 1997 8-hour ozone NAAQS, and the designations became effective on June 15, 2004.

Ground-level ozone is not generally emitted directly by sources. Rather, emitted NO_X and Volatile Organic Compounds (VOC) react in the presence of sunlight to form ground-level ozone, as a secondary compound, along with other secondary compounds. NO_X and VOC are referred to as “ozone precursors.” Reduction of peak ground-level ozone concentrations is achieved through controlling VOC and NO_X emissions.

The CAA, title 1, part D contains two sets of provisions—subparts 1 and 2—that address planning and emission control requirements for ozone nonattainment areas. Subpart 1 contains general, less prescriptive requirements for all nonattainment areas of any pollutant governed by a NAAQS. Subpart 2 contains more specific requirements for ozone nonattainment areas classified under section 181 of the CAA. The Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL areas are classified as moderate nonattainment areas under the 1997 8-hour ozone NAAQS.^[1]

The subpart 2 ozone plan requirements under the CAA with respect to control of VOC and NO_X emissions depend on the ozone nonattainment classification of an area. The air quality planning and control requirements for the reduction of NO_X emissions are contained in section 182(f) of the CAA. Section 182(f) requires States with areas classified as moderate nonattainment and above to adopt and implement the same level of NO_X emission controls for major stationary sources as are required for major stationary sources of VOC emissions. Section 182(f) also provides that these NO_X emission reduction requirements do not apply to an area outside of an ozone transport region if EPA determines that additional reductions of NO_X emissions would not contribute to attainment of the ozone standard in the area. In areas where the ozone standard is attained, as demonstrated by complete, quality-assured air quality data, without the implementation of the additional section 182(f) NO_X emission controls, it is clear that the additional NO_X emission reductions required by section 182(f) did not contribute to attainment of the ozone standard.

On March 17, 2008, EPA notified Douglas P. Scott, Director of the Illinois EPA, that EPA had determined that the State of Illinois had failed to submit a CAA-required NO_X RACT State Implementation Plan (SIP) revision (the NO_X RACT emission control rules) for the Illinois portions of the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL ozone nonattainment areas. EPA formalized this finding in the Federal Register on March 24, 2008 (73 FR 15416), and that action commenced the sanctions process outlined by section 179 of the CAA and 40 CFR 52.31. See 59 FR 39832, August 4, 1994. Under this process, the new source two-to-one (2:1) emissions offset sanction would take effect in the Illinois ozone nonattainment areas on September 24, 2009. The sanctions clock would run and any imposed sanctions would remain in effect until either a NO_X RACT SIP revision is submitted to EPA by the State of Illinois and is affirmatively determined complete by EPA, or a NO_X control waiver, under section 182(f), is granted by EPA.

On September 1 and 2, 2009, the Illinois EPA submitted adopted NO_X emission control regulations, as a requested SIP revision, to meet the CAA NO_X RACT requirement. On September 16, 2009, EPA determined this SIP revision submittal to be complete, terminating the sanctions clock activated on March 24, 2008.^[2] EPA continues to review this SIP revision, but has not yet completed rulemaking on this requested SIP revision. Therefore, the Illinois SIP does not yet contain the Illinois NO_X emission control rules. In addition, it is noted that Illinois has not yet completed implementation of the NO_X emission control rules.

The criteria established for determining the applicability of section 182(f) NO_X emission controls and the evaluation of section 182(f) NO_X emission control waiver requests are set forth in a January 14, 2005, EPA policy memorandum, “Guidance on Limiting Nitrogen Oxides (NO_X) Requirements Related to 8-Hour Ozone Implementation,” from Stephen D. Page, Director, Office of Air Quality Planning and Standards.

III. State Petition

On July 29, 2010, Illinois EPA submitted a request for a NO_X RACT waiver for the Illinois ozone nonattainment areas.^[3] This NO_X RACT waiver was requested for the 1997 8-hour ozone standard. Illinois EPA requested that EPA consider the NO_X emission control rules submitted on September 1 and 2, 2009, for approval as NO_X RACT in the Illinois SIP under a possible new ozone standard that EPA is currently considering.

Illinois EPA based its NO_X RACT waiver request on ozone air quality data for 2007-2009, which demonstrate that the 1997 8-hour ozone NAAQS has been attained in the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL areas without the implementation of NOX RACT in the Illinois portions of these areas.

IV. EPA Review of the Petition

A. Have the ozone nonattainment areas attained the 1997 8-hour ozone NAAQS?

An area may be considered to be attaining the 1997 8-hour ozone standard if there are no violations of the standard, as determined in accordance with 40 CFR 50.10 and appendix I, based on the most recent three years of complete, quality-assured air quality monitoring data at all ozone monitoring sites in the area and in its nearby downwind environs. To attain this standard, the average of the annual fourth-high daily maximum 8-hour average ozone concentrations measured and recorded at each monitoring site over the most recent 3-year period (the monitoring site's ozone design value) must not exceed the ozone standard. Based on an ozone data rounding convention described in 40 CFR 50, appendix I, the 1997 8-hour ozone standard is attained if the area's ozone design value ^[4] is 0.084 ppm or less. The data must be collected and quality-assured in accordance with 40 CFR 58, and must be recorded in EPA's Air Quality System (AQS). The ozone monitors generally should have remained at the same locations for duration of the monitoring period required to demonstrate attainment of the ozone standard. The data supporting attainment of the standard must be complete in accordance with 40 CFR 50, appendix I.

Table 1 summarizes the annual fourth-high daily maximum 8-hour ozone concentrations and their 3-year (2007-2009) averages for all monitors in the Chicago-Gary-Lake County, IL-IN area and for the Chiwaukee Prairie monitoring site in Wisconsin (considered to be a high ozone monitor in the downwind environs of the Chicago-Gary-Lake County, IL-IN area). These data reflect peak ozone concentrations quality assured and reported by the States of Illinois, Indiana, and Wisconsin.

Table 1—Annual Fourth-High Daily Maximum 8-Hour Ozone Concentrations in Parts per Million (ppm) and 3-Year Averages for the Chicago-Gary-Lake County, IL-IN Area

State/monitoring site	2007	2008	2009	3-Year average
Indiana Monitoring Sites
Gary	0.085	0.062	0.058	0.068
Hammond	0.077	0.068	0.065	0.070
Ogden Dunes	0.084	0.069	0.067	0.073
Valparaiso	0.080	0.061	0.064	0.068
Whiting	0.088	0.062	0.062	0.071
Illinois Monitoring Sites
Alsip	0.085	0.066	0.069	0.073
Chicago-Cheltenham	0.082	0.066	0.065	0.071
Chicago-Adams	0.084	0.058	0.076	0.073
Chicago-Ellis Avenue	0.079	0.063	0.060	0.068
Chicago-Ohio Street	0.075	0.063	0.062	0.067
Chicago-Lawndale	0.080	0.066	0.067	0.071
Chicago-Hurlbut Street	0.079	0.063	0.064	0.069
Lemont	0.085	0.071	0.067	0.074
Cicero	0.068	0.060	0.067	0.065
Northbrook	0.076	0.063	0.069	0.069
Evanston	0.080	0.058	0.064	0.067
Lisle	0.072	0.057	0.059	0.063
Waukegan	0.081	0.061	0.057	0.066
Illinois Beach State Park	0.080	0.067	0.075	0.074
Cary	0.074	0.063	0.066	0.068
Essex Road	0.071	0.057	0.063	0.064
Wisconsin Monitoring Site
Chiwaukee Prairie	0.085	0.069	0.071	0.075

Table 2 summarizes the annual fourth-high daily maximum 8-hour ozone concentrations and their 3-year (2007-2009) averages for all monitors in the St. Louis, MO-IL area. These data reflect peak ozone concentrations quality assured and reported by the States of Illinois and Missouri.

Table 2—Annual Fourth-High Daily Maximum 8-Hour Ozone Concentrations and 3-Year Averages in ppm for the St. Louis, MO-IL Area

State/monitoring site	2007	2008	2009	3-Year average
Illinois Sites
Jerseyville	0.075	0.069	0.068	0.070
Alton	0.081	0.068	0.067	0.072
Maryville	0.087	0.070	0.074	0.077
Wood River	0.086	0.067	0.066	0.073
East St. Louis	0.077	0.064	0.069	0.070
Missouri Sites
Arnold	0.087	0.070	0.070	0.075
Orchard Farm	0.083	0.072	0.072	0.075
West Alton	0.089	0.076	0.071	0.078
Maryland Heights	0.094	0.069	0.067	0.076
Pacific	0.085	0.064	0.064	0.071
Blair Street	0.087	0.073	0.065	0.075

Review of the 2007-2009 ozone concentrations and site-specific ozone design values (3-year averages) in Tables 1 and 2 shows that all of the ozone monitoring sites in the two areas were attaining the 1997 8-hour ozone NAAQS during this period. Therefore, based on the most recent three years of quality-assured ozone monitoring data, the 1997 8-hour ozone standard has been attained in these areas. Preliminary 2010 ozone data show that the 1997 8-hour ozone standard continues to be attained in the two areas.

B. EPA's Analysis of Illinois' NO _X RACT Waiver Petition

EPA's guidance document, “Guidance on Limiting Nitrogen Oxides (NO_X) Requirements Related to 8-Hour Ozone Implementation,” sets forth the criteria for demonstrating that further NO_X emission reductions in an ozone nonattainment area will not contribute to ozone attainment. The guidance provides that three consecutive years of monitoring data documenting ozone levels attaining the ozone NAAQS in areas in which a State has not implemented certain NO_X emission controls is adequate to demonstrate that the additional NO_X emission reductions will not aid in achieving attainment of the ozone NAAQS. As described in the guidance document, approval of the NO_X emission control exemption is granted by the EPA on a contingent basis. The NO_X emission control exemption continues only as long as the State continues to monitor attainment of the ozone NAAQS. If, prior to redesignation of the area to attainment of the ozone NAAQS, the area violates the 1997 8-hour ozone NAAQS, as defined at 40 CFR 50.10 and appendix I, EPA will undertake rulemaking to withdraw the NO_X emission control exemption, the area would once again be subject to the NO_X emission control requirements under section 182(f) of the CAA.

EPA's review of the ozone monitoring data and Illinois' NO_X emission control exemption request shows that Illinois has complied with the requirements for a NO_X RACT exemption in the State's 8-hour ozone nonattainment areas under section 182(f) of the CAA consistent with the guidelines contained in EPA's January 14, 2005, guidance document. Therefore, EPA proposes to determine that the State of Illinois qualifies for exemption from NO_X RACT requirements for the Illinois portions of the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL ozone nonattainment areas for the purposes of attaining the 1997 8-hour ozone NAAQS.

V. What are the environmental effects of this action?

The section 182(f) NO_X RACT exemption is based on a finding that additional reductions of NO_X would not contribute to attainment of the 1997 8-hour ozone NAAQS in the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL ozone nonattainment areas. These areas have three consecutive years of ozone levels attaining the ozone standard even though Illinois has not implemented NO_X RACT rules.

While EPA is proposing to waive the requirements to control NO_X emissions through NO_X RACT in the Illinois ozone nonattaiment areas on the basis that NO_X emission reductions would not contribute to attainment of the ozone NAAQS in the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL areas, EPA recognizes that there are other benefits to controlling NO_X emissions. These benefits include reducing acid deposition, reducing nitrogen deposition in sensitive wetlands, estuaries, and their watersheds, and mitigating ozone transport to downwind ozone nonattainment areas. Illinois will continue to be required to control NO_X emissions from certain NO_X sources under other CAA programs, such as the Acid Rain program in title IV of the CAA, for purposes of achieving these environmental benefits. This proposed NO_X RACT waiver will not affect other existing and pending NO_X emission control requirements for Illinois needed to achieve these environmental benefits.

In addition, EPA notes that an approval of this waiver request is solely for purposes of the CAA requirements to meet the 1997 8-hour ozone NAAQS. The waiver would not apply for purposes of the ozone NAAQS promulgated in 2008 (March 27, 2008, 73 FR 16435) or for purposes of any future ozone NAAQS EPA may promulgate. To the extent section 182(f) applies in this area for purposes of the 2008 or any future ozone NAAQS, the State would need to submit a NO_X RACT SIP or would need to demonstrate that a waiver is appropriate for purposes of that different ozone NAAQS.

VI. EPA's Proposed Action

EPA is proposing approval of Illinois' request to exempt the State's 8-hour ozone nonattainment areas from the section 182(f) NO_X RACT requirement. This proposed approval is based on EPA's review of the evidence that the requirements of section 182(f)(1)(A), as elaborated upon in EPA's guidance for section 182(f) exemptions, have been met for Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL ozone nonattainment areas. In the future, if EPA determines that a violation of the 1997 8-hour ozone NAAQS has occurred in the Chicago-Gary-Lake County, IL-IN area (or at the Chiwaukee Prairie monitoring site in Kenosha County, Wisconsin) or in the St. Louis, MO-IL area while the Illinois portions of these ozone nonattainment areas are designated as nonattainment for the 1997 8-hour ozone NAAQS, EPA will take action to revoke the exemption.

Final approval of Illinois' NO_X RACT exemption request would suspend a requirement for a NO_X RACT FIP stemming from EPA's March 24, 2008, finding of Illinois' failure to submit the NO_X RACT rules. The suspension would remain in place contingent upon continued attainment of the 1997 8-hour ozone NAAQS in the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL areas. If EPA approves a redesignation request for either of these areas for the 1997 8-hour ozone NAAQS, the NO_X RACT FIP clock will permanently stop at that time. If EPA determines that there is a violation of the 1997 8-hour ozone NAAQS while either of these areas remain designated as nonattainment for the 1997 8-hour ozone NAAQS, the NO_X RACT waiver will no longer be applicable as of the effective date of any such determination for the violating area by EPA. At that time, the NO_X RACT FIP requirement will no longer be suspended and the NO_X RACT FIP clock will restart at the point at which it stopped. EPA will provide notice in the Federal Register of any such waiver revocation and of the restarting of the NO_X RACT FIP clock.

VII. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve State choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves State law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
• Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and
• Does not provide EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, this rule does not have Tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because the SIP is not approved to apply in Indian country located in the State, and EPA notes that it will not impose substantial direct costs on Tribal governments or preempt Tribal law.

List of Subjects in 40 CFR Part 52

• Environmental protection
• Air pollution control
• Intergovernmental relations
• Nitrogen dioxide
• Ozone
• Volatile organic compounds

Dated: November 23, 2010.

Susan Hedman,

Regional Administrator, Region 5.

Footnotes

1.  On May 11, 2010 (75 FR 26113), EPA published a final rule to redesignate Lake and Porter Counties, Indiana to attainment of the 1997 8-hour ozone NAAQS. The Illinois portion of the Chicago-Gary-Lake County, IL-IN area remains designated as a nonattainment area for the 1997 8-hour ozone NAAQS.

2.  Termination of the sanctions clock did not suspend or terminate a FIP clock (also started on March 24, 2008) requiring EPA to promulgate a NO_X RACT FIP within two years of the determination that Illinois had failed to submit required NO_X RACT rules. The FIP clock can only be terminated (EPA's obligation to promulgate a FIP is ended) if EPA approves Illinois' NO_X emission control rules as NO_X RACT in the Illinois SIP or suspended if EPA approves a waiver of the NO_X RACT requirement for both of the ozone nonattainment areas. If the FIP clock is suspended through approval of the NO_X RACT waiver, the suspension of the FIP clock continues only as long as the two ozone nonattainment areas continue to attain the 1997 8-hour ozone NAAQS. The FIP clock is terminated if EPA approves the redesignation of both areas (the Illinois portions of the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL 8-hour ozone nonattainment areas) to attainment of the 1997 8-hour ozone NAAQS.

3.  The Illinois portion of the Chicago-Gary-Lake County, IL-IN 8-hour ozone nonattainment area includes Cook, DuPage, Kane, Lake, McHenry, and Will Counties, and portions of Grundy (Aux Sable and Goose Lake Townships) and Kendall (Oswego Township) Counties. The Illinois portion of the St. Louis, MO-IL 8-hour ozone nonattainment area includes Jersey, Madison, Monroe, and St. Clair Counties.

4.  The worst-case monitoring site-specific ozone design value in the area and in its downwind environs.