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ENVIRONMENTAL PROTECTION AGENCY

Environmental Protection Agency

CFR Citation: 40 CFR Part 52

EPA ID: [EPA-R05-OAR-2006-0563; FRL-8266-5]

NOTICE: PROPOSED RULES

ACTION: Air quality implementation plans; approval and promulgation; various States:

DOCUMENT ACTION: Proposed rule.

SUBJECT CATEGORY: Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes; Michigan; Redesignation of Flint, Muskegon, Benton Harbor, and Cass County 8-hour Ozone Nonattainment Areas to Attainment for Ozone

DATES: Comments must be received on or before February 7, 2007.

DOCUMENT SUMMARY: EPA is proposing to make determinations under the Clean Air Act (CAA) that the nonattainment areas of Flint (Genesee and Lapeer Counties), Muskegon (Muskegon County), Benton Harbor (Berrien County), and Cass County have attained the 8hour ozone National Ambient Air Quality Standard (NAAQS). These determinations are based on three years of complete, qualityassured ambient air quality monitoring data for the 20042006 seasons that demonstrate that the 8hour ozone NAAQS have been attained in the areas.

EPA is proposing to approve requests from the State of Michigan to redesignate the Flint, Muskegon, Benton Harbor, and Cass County areas to attainment of the 8hour ozone NAAQS. These requests were submitted by the Michigan Department of Environmental Quality (MDEQ) on June 13, 2006, and supplemented on August 25, 2006, and November 30, 2006.

In proposing to approve this request, EPA also is proposing to approve the State's plans for maintaining the 8hour ozone NAAQS through 2018 in the areas as revisions to the Michigan State Implementation Plan (SIP). EPA also finds adequate and is proposing to approve the State's 2018 Motor Vehicle Emission Budgets (MVEBs) for the Flint, Muskegon, Benton Harbor, and Cass County areas.

SUMMARY: Michigan,

SUPPLEMENTAL INFORMATION

Throughout this document whenever ``we,'' ``us,'' or ``our'' is used, we mean EPA. This supplementary information section is arranged as follows:
Table of Contents
I. What Should I Consider as I Prepare My Comments for EPA? II. What Actions Is EPA Proposing To Take?
III. What Is the Background for These Actions?
IV. What Are the Criteria for Redesignation?
V. Why Is EPA Proposing To Take These Actions?
VI. What Is the Effect of These Actions?
VII. What Is EPA's Analysis of the Requests?

i. Attainment Determination and Redesignation

ii. Adequacy of Michigan's Motor Vehicle Emission Budgets VIII. What Actions Are EPA Taking Today?
IX. 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 directionsThe 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 that 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.

II. What Actions Is EPA Proposing to Take?

EPA is proposing to take several related actions. EPA is proposing to make determinations that the Flint (Genesee and Lapeer Counties), Muskegon (Muskegon County), Benton Harbor (Berrien County), and Cass County, Michigan nonattainment areas have attained the 8hour ozone standard and that these areas have met the requirements for redesignation under section 107(d)(3)(E) of the CAA. EPA is thus proposing to approve Michigan's request to change the legal designations of the Flint, Muskegon, Benton Harbor, and Cass County areas from nonattainment to attainment for the 8hour ozone NAAQS. EPA is also proposing to approve Michigan's maintenance plan SIP revisions for the Flint, Muskegon, Benton Harbor, and Cass County areas (such approval being one of the CAA criteria for redesignation to attainment status). The maintenance plans are designed to keep the Flint, Muskegon, Benton Harbor, and Cass County areas in attainment of the ozone NAAQS through 2018. Additionally, EPA is announcing its action on the Adequacy Process for the newlyestablished 2018 MVEBs for the Flint, Muskegon, Benton Harbor, and Cass County areas. The adequacy comment period for the 2018 MVEBs began on August 4, 2006, with EPA's posting of the availability of these submittals on EPA's Adequacy Web site (at http://www.epa.gov/otaq/stateresources/transconf/adequacy.htm ). The adequacy comment period for these MVEBs ended on
September 5, 2006. EPA did not receive any requests for these submittals, or adverse comments on these submittals during the adequacy comment period. Please see the Adequacy Section of this rulemaking for further explanation on this process. Therefore, we find adequate, and are proposing to approve, the State's 2018 MVEBs for transportation conformity purposes.

III. What Is the Background for These Actions?

Groundlevel ozone is not emitted directly by sources. Rather, emissions of nitrogen oxides (NOX) and volatile organic compounds (VOCs) react in the presence of sunlight to form groundlevel ozone. NOX and VOCs are referred to as precursors of ozone.

The CAA establishes a process for air quality management through the NAAQS. Before promulgation of the current 8hour standard, the ozone NAAQS was based on a 1hour standard. EPA revoked the 1hour ozone NAAQS on June 15, 2005. At the time EPA revoked the 1hour standard, the Flint, Muskegon, Benton Harbor, and Cass County areas were all designated as attainment under the 1hour ozone NAAQS.

On July 18, 1997, EPA promulgated a new 8hour ozone NAAQS of 0.08 parts per million (ppm). This new standard is more stringent than the previous 1hour standard. On April 30, 2004 (69 FR 23857), EPA published a final rule designating and classifying areas under the 8 hour ozone NAAQS. These designations and classifications became effective June 15, 2004. The CAA required EPA to designate as nonattainment any area that was violating the 8hour ozone NAAQS based on the three most recent years of air quality data, 20012003.

The CAA contains two sets of provisionssubpart 1 and subpart 2 that address planning and control requirements for nonattainment areas. (Both are found in title I, part D, 42 U.S.C. 75017509a and 7511 7511f, respectively.) Subpart 1 (which EPA refers to as ``basic'' nonattainment) contains general, less prescriptive, requirements for nonattainment areas for any pollutant, including ozone, governed by a NAAQS. Subpart 2 (which EPA refers to as ``classified'' nonattainment) provides more specific requirements for ozone nonattainment areas. Some ozone nonattainment areas are subject only to the provisions of subpart 1. Other ozone nonattainment areas are subject to the provisions of both subparts 1 and 2. Under EPA's 8hour ozone implementation rule, signed on April 15, 2004 (69 FR 23951 (April 30, 2004)), an area was classified under subpart 2 based on its 8hour ozone design value (i.e., the 3year average annual fourthhighest daily maximum 8hour average ozone concentration), if it had a 1hour design value at or above 0.121 ppm (the lowest 1hour design value in Table 1 of subpart 2) (69 FR 23954). All other areas were covered under Subpart 1, based upon their 8hour design values (69 FR 23958). The Muskegon and Cass County areas were designated as subpart 2, 8hour ozone moderate nonattainment areas by EPA on April 30, 2004, (69 FR 23857, 23911), based on air quality monitoring data from 20012003. The Flint and Benton
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Harbor areas were designated by EPA as subpart 1, 8hour nonattainment areas (69 FR 2391023911), based on 20012003 monitoring data.

Under section 181(a)(4) of the CAA EPA may adjust the classification of an ozone nonattainment area to the next higher or lower classification if the design value for the area is within five percent of the cut off for that higher or lower classification. On September 22, 2004, EPA adjusted the classification of several nonattainment areas which had been designated and classified under subpart 2 on April 30, 2004. At that time, EPA adjusted the classifications of the Muskegon and Cass County nonattainment areas from moderate to marginal (69 FR 56697, 567085670).

40 CFR 50.10 and 40 CFR part 50, Appendix I provide that the 8hour ozone standard is attained when the 3year average of the annual fourthhighest daily maximum 8hour average ozone concentration is less than or equal to 0.08 ppm when rounded. The data completeness requirement is met when the average percent of days with valid ambient monitoring data is greater than 90%, and no single year has less than 75% data completeness. See 40 CFR part 50, Appendix I, section 2.3(d).

On June 13, 2006, Michigan requested that EPA redesignate the Flint, Muskegon, Benton Harbor, and Cass County areas to attainment for the 8hour ozone standard. This submittal was supplemented on August 25, 2006, and November 30, 2006. Michigan included complete, quality assured air monitoring data for the 2004 through 2006 ozone season, indicating the 8hour NAAQS for ozone had been attained for the Flint, Muskegon, Benton Harbor, and Cass County areas. Under the CAA, a nonattainment area may be redesignated to attainment if sufficient complete, qualityassured air monitoring data are available for the Administrator to determine that the area has attained the standard, and the area meets the other CAA redesignation requirements in section 107(d)(3)(E).

IV. What Are the Criteria for Redesignation?

The CAA provides the requirements for redesignating a nonattainment area to attainment. Specifically, section 107(d)(3)(E) allows for redesignation provided that: (1) The Administrator determines that the area has attained the applicable NAAQS; (2) the Administrator has fully approved the applicable implementation plan for the area under section 110(k); (3) the Administrator determines that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable SIP and applicable federal air pollutant control regulations and other permanent and enforceable reductions; (4) the Administrator has fully approved a maintenance plan for the area as meeting the requirements of section 175A; and, (5) the state containing such area has met all requirements applicable to the area under section 110 and part D.

EPA provided guidance on redesignation in the General Preamble for the Implementation of Title I of the CAA Amendments of 1990, on April 16, 1992 (57 FR 13498), and supplemented this guidance on April 28, 1992 (57 FR 18070). EPA has provided further guidance on processing redesignation requests in the following documents:
``Ozone and Carbon Monoxide Design Value Calculations'', Memorandum from William G. Laxton, Director Technical Support Division, June 18, 1990;
``Maintenance Plans for Redesignation of Ozone and Carbon Monoxide Nonattainment Areas,'' Memorandum from G.T. Helms, Chief, Ozone/Carbon Monoxide Programs Branch, April 30, 1992;
``Contingency Measures for Ozone and Carbon Monoxide (CO) Redesignations,'' Memorandum from G.T. Helms, Chief, Ozone/Carbon Monoxide Programs Branch, June 1, 1992;
``Procedures for Processing Requests to Redesignate Areas to Attainment,'' Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992;
``State Implementation Plan (SIP) Actions Submitted in Response to Clean Air Act (ACT) Deadlines,'' Memorandum from John Calcagni, Director, Air Quality Management Division, October 28, 1992; ``Technical Support Documents (TSD's) for Redesignation of Ozone and Carbon Monoxide (CO) Nonattainment Areas,'' Memorandum from G.T. Helms, Chief, Ozone/Carbon Monoxide Programs Branch, August 17, 1993; ``State Implementation Plan (SIP) Requirements for Areas Submitting Requests for Redesignation to Attainment of the Ozone and Carbon Monoxide (CO) National Ambient Air Quality Standards (NAAQS) On or After November 15, 1992,'' Memorandum from Michael H. Shapiro, Acting Assistant Administrator for Air and Radiation, September 17, 1993; ``Use of Actual Emissions in Maintenance Demonstrations for Ozone and CO Nonattainment Areas,'' Memorandum from D. Kent Berry, Acting Director, Air Quality Management Division, to Air Division Directors, Regions 110, dated November 30, 1993.
``Part D New Source Review (part D NSR) Requirements for Areas Requesting Redesignation to Attainment,'' Memorandum from Mary D. Nichols, Assistant Administrator for Air and Radiation, October 14, 1994; and
``Reasonable Further Progress, Attainment Demonstration, and Related Requirements for Ozone Nonattainment Areas Meeting the Ozone National Ambient Air Quality Standard,'' Memorandum from John S. Seitz, Director, Office of Air Quality Planning and Standards, May 10, 1995. V. Why Is EPA Proposing to Take These Actions?

On June 13, 2006, Michigan requested redesignation of the Flint, Muskegon, Benton Harbor, and Cass County areas to attainment for the 8 hour ozone standard. Michigan supplemented its submittal on August 25, 2006, and November 30, 2006. EPA believes that the areas have attained the standard and have met the requirements for redesignation set forth in section 107(d)(3)(E) of the CAA.

VI. What Is the Effect of These Actions?

Approval of the redesignation request would change the official designation of the areas for the 8hour ozone NAAQS found at 40 CFR part 81. It would also incorporate into the Michigan SIP plans for maintaining the 8hour ozone NAAQS through 2018. The maintenance plans include contingency measures to remedy future violations of the 8hour NAAQS. They also establish MVEBs for the year 2018 of 25.68 tons per day (tpd) VOC and 37.99 tpd NOX for the Flint area, 6.67 tpd VOC and 11.00 tpd NOX for the Muskegon area, 9.16 tpd VOC and 15.19 tpd NOX for the Benton Harbor area, and 2.76 tpd VOC and 3.40 tpd NOX for the Cass County area.
VII. What Is EPA's Analysis of the Requests?

i. Attainment Determination and Redesignation

EPA is proposing to make determinations that the Flint, Muskegon, Benton Harbor, and Cass County nonattainment areas have attained the 8 hour ozone standard and that the areas have met all other applicable section 107(d)(3)(E) redesignation criteria. The basis for EPA's determinations is as follows:
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1. The Areas Have Attained the 8hour Ozone NAAQS. (Section 107(d)(3)(E)(i))

EPA is proposing to make determinations that the Flint, Muskegon, Benton Harbor, and Cass County areas have attained the 8hour ozone NAAQS. For ozone, an area may be considered to be attaining the 8hour ozone NAAQS if there are no violations, as determined in accordance with 40 CFR 50.10 and part 50, Appendix I, based on three complete, consecutive calendar years of qualityassured air quality monitoring data. To attain this standard, the 3year average of the fourthhighest daily maximum 8hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.08 ppm. Based on the rounding convention described in 40 CFR part 50, Appendix I, the standard is attained if the design value is 0.084 ppm or below. The data must be collected and qualityassured in accordance with 40 CFR part 58, and recorded in the Aerometric Information Retrieval System (AIRS). The monitors generally should have remained at the same location for the duration of the monitoring period required for demonstrating attainment.

MDEQ submitted ozone monitoring data for the 2004 to 2006 ozone seasons. The MDEQ quality assured the ambient monitoring data in accordance with 40 CFR 58.10, and recorded it in the AIRS database, thus making the data publicly available. The data meets the completeness criteria in 40 CFR part 50, Appendix I, which requires a minimum completeness of 75 percent annually and 90 percent over each three year period. Monitoring data is presented in Table 1, below. Data completeness information is presented in Table 2, below.
Table 1.Annual 4th High Daily Maximum 8hour Ozone Concentration and 3Year Averages of 4th High Daily Maximum 8Hour Ozone Concentrations Design value 2004 4th 2005 4th 2006 4th 20042006 2006 rounded Area County Monitor high (ppm) high (ppm) high (ppm) avg. (ppm) to 2 decimals (ppm) Flint............................... Genesee............... Flint 260490021...... 0.075 0.079 0.075 0.076 0.08 Lapeer................ Otisville 260490021.. 0.077 0.080 0.075 0.077 0.08 Muskegon............................ Muskegon.............. Muskegon 261210039... 0.070 0.090 0.091 0.083 0.08 Benton Harbor....................... Berrien............... Coloma 260210014..... 0.073 0.090 0.077 0.080 0.08 Cass................................ Cass.................. Cassopolis 260270003. 0.077 0.086 0.073 0.078 0.08 Table 2.Data Completeness in Percent (%) Annual Minimum of 75% Completeness 3Year Period Average Minimum of 90% Area County Monitor Completeness 2004 (%) 2005 (%) 2006 (%) 20042006 average (%) Flint................................... Genesee.................... Flint 260490021.......... 100 75 97 91 Lapeer..................... Otisville 260492001...... 100 87 100 96 Muskegon................................ Muskegon................... Muskegon 261210039....... 99 96 99 98 Benton Harbor........................... Berrien.................... Coloma 260210014......... 98 98 100 99 Cass.................................... Cass....................... Cassopolis................ 92 100 98 97

In addition, as discussed below with respect to the maintenance plans, MDEQ has committed to continue operating an EPA approved monitoring network in accordance with 40 CFR part 58. In summary, EPA believes that the data submitted by Michigan provide an adequate demonstration that the Flint, Muskegon, Benton Harbor, and Cass County areas have attained the 8hour ozone NAAQS.
2. The Areas Have Met All Applicable Requirements Under Section 110 and Part D; and the Areas Have Fully Approved SIPs Under Section 110(k) (Sections 107(d)(3)(E)(v) and 107(d)(3)(E)(ii))

We have determined that Michigan has met all currently applicable SIP requirements for purposes of redesignation for the Flint, Muskegon, Benton Harbor, and Cass County areas under Section 110 of the CAA (general SIP requirements). We have also determined that the Michigan SIP meets all SIP requirements currently applicable for purposes of redesignation under Part D of Title I of the CAA (requirements specific to Subpart 1 and Subpart 2 marginal nonattainment areas), in accordance with section 107(d)(3)(E)(v). In addition, we have determined that the Michigan SIP is fully approved with respect to all applicable requirements for purposes of redesignation, in accordance with section 107(d)(3)(E)(ii). In making these determinations, we have ascertained what SIP requirements are applicable to the areas for purposes of redesignation, and have determined that the portions of the SIP meeting these requirements are fully approved under section 110(k) of the CAA. As discussed more fully below, SIPs must be fully approved only with respect to currently applicable requirements of the CAA.

a. The Flint, Muskegon, Benton Harbor, and Cass County areas have met all applicable requirements under section 110 and part D of the CAA. The September 4, 1992, Calcagni memorandum (see ``Procedures for Processing Requests to Redesignate Areas to Attainment,'' Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992) describes EPA's interpretation of section 107(d)(3)(E) of the CAA. Under this interpretation, a state and the area it wishes to redesignate must meet the relevant CAA
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requirements that are due prior to the state's submittal of a complete redesignation request for the area. See also the September 17, 1993, Michael Shapiro memorandum and 60 FR 12459, 1246566 (March 7, 1995) (redesignation of DetroitAnn Arbor, Michigan to attainment of the 1 hour ozone NAAQS). Applicable requirements of the CAA that come due subsequent to the state's submittal of a complete request remain applicable until a redesignation to attainment is approved, but are not required as a prerequisite to redesignation. See section 175A(c) of the CAA; Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004). See also 68 FR 25424, 25427 (May 12, 2003) (redesignation of the St. Louis/East St. Louis area to attainment of the 1hour ozone NAAQS).

General SIP requirements. Section 110(a) of title I of the CAA contains the general requirements for a SIP. Section 110(a)(2) provides that the implementation plan submitted by a state must have been adopted by the state after reasonable public notice and hearing, and that, among other things, it includes enforceable emission limitations and other control measures, means or techniques necessary to meet the requirements of the CAA; provides for establishment and operation of appropriate devices, methods, systems and procedures necessary to monitor ambient air quality; provides for implementation of a source permit program to regulate the modification and construction of any stationary source within the areas covered by the plan; includes provisions for the implementation of part C, Prevention of Significant Deterioration (PSD) and part D, New Source Review (NSR) permit programs; includes criteria for stationary source emission control measures, monitoring, and reporting; includes provisions for air quality modeling; and provides for public and local agency participation in planning and emission control rule development.

Section 110(a)(2)(D) of the CAA requires that SIPs contain measures to prevent sources in a state from significantly contributing to air quality problems in another state. To implement this provision, EPA has required certain states to establish programs to address transport of air pollutants (NOX SIP Call,\1\ Clean Air Interstate Rule (CAIR)(70 FR 25162)). However, the section 110(a)(2)(D) requirements for a state are not linked with a particular nonattainment area's designation and classification. EPA believes that the requirements linked with a particular nonattainment area's designation and classification are the relevant measures to evaluate in reviewing a redesignation request. When the transport SIP submittal requirements are applicable to a state, they will continue to apply to the state regardless of the designation of any one particular area in the state. Therefore, we believe that these requirements should not be construed to be applicable requirements for purposes of redesignation. Further, we believe that the other section 110 elements described above that are not connected with nonattainment plan submissions and not linked with an area's attainment status are also not applicable requirements for purposes of redesignation. A state remains subject to these requirements after an area is redesignated to attainment. We conclude that only the section 110 and part D requirements which are linked with a particular area's designation and classification are the relevant measures which we may consider in evaluating a redesignation request. This approach is consistent with EPA's existing policy on applicability of conformity and oxygenated fuels requirements for redesignation purposes, as well as with section 184 ozone transport requirements. See Reading, Pennsylvania, proposed and final rulemakings (61 FR 53174 53176, October 10, 1996), (62 FR 24826, May 7, 1997); ClevelandAkron Lorain, Ohio, final rulemaking (61 FR 20458, May 7, 1996); and Tampa, Florida, final rulemaking (60 FR 62748, December 7, 1995). See also the discussion on this issue in the Cincinnati ozone redesignation (65 FR 37890, June 19, 2000), and in the Pittsburgh ozone redesignation (66 FR 50399, October 19, 2001).

As discussed above, we believe that section 110 elements which are not linked to the area's nonattainment status are not applicable for purposes of redesignation. Because there are no section 110 requirements that are linked to the part D requirements for 8hour ozone nonattainment areas that have become due, as explained below, there are no Part D requirements applicable for purposes of redesignation under the 8hour standard.
\1\ On October 27, 1998 (63 FR 57356), EPA issued a
NOX SIP call, requiring the District of Columbia and 22 states, including portions of Michigan, to reduce emissions of NOX in order to reduce the transport of ozone and ozone precursors. In compliance with EPA's NOX SIP call, MDEQ has developed rules governing the control of NOX emissions from electric generating units (EGUs), major nonEGU industrial boilers, and major cement kilns. EPA approved Michigan's rules as fulfilling Phase I of the NOX SIP Call on May 4, 2005 (70 FR 23029).

Part D Requirements. EPA has determined that the Michigan SIP meets applicable SIP requirements under part D of the CAA since no requirements applicable for purposes of redesignation became due for the 8hour ozone standard prior to submission of the redesignation request for the Flint, Muskegon, Benton Harbor, and Cass County areas. Under part D, an area's classification determines the requirements to which it will be subject. Subpart 1 of part D, which includes sections 172176 of the CAA, sets forth the basic nonattainment requirements applicable to all nonattainment areas. Section 182 of the CAA, which is found in subpart 2 of part D, establishes additional specific requirements depending on the area's nonattainment classification. The Flint and Benton Harbor areas are both classified as subpart 1 nonattainment areas and, therefore, subpart 2 requirements do not apply. The Muskegon and Cass County areas are classified as subpart 2 marginal nonattainment areas and, therefore, both subpart 1 and subpart 2 requirements apply.

Part D, Subpart 1 applicable SIP requirements. For purposes of evaluating these redesignation requests, the applicable part D, subpart 1 SIP requirements for Flint, Benton Harbor, Muskegon, and Cass County areas are contained in sections 172(c)(1)(9). A thorough discussion of the requirements contained in section 172 can be found in the General Preamble for Implementation of Title I (General Preamble 57 FR 13498, April 16, 1992).

Part D, Subpart 2 applicable SIP requirements. For purposes of evaluating these redesignation requests, the applicable part D, subpart 2 SIP requirements for the Muskegon and Cass County areas are contained in section 182(a). A thorough discussion of the requirements contained in section 182(a) can be found in the General Preamble (57 FR 13498, 1350213507 (April 16, 1992)).

No requirements applicable for purposes of redesignation under part D became due prior to submission of the redesignation request, and, therefore, none is applicable to the areas for purposes of redesignation. Since the State of Michigan has submitted complete ozone redesignation requests for the Flint, Muskegon, Benton Harbor, and Cass County areas prior to the deadline for any submissions required for purposes of redesignation, we have determined that these requirements do not apply to the Flint, Muskegon,
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Benton Harbor, and Cass County areas for purposes of redesignation.

Furthermore, EPA has determined that, since PSD requirements will apply after redesignation, areas redesignating need not comply with the requirement that a NSR program be approved prior to redesignation, provided that these areas demonstrate maintenance of the NAAQS without part D NSR. A more detailed rationale for this view is described in a memorandum from Mary Nichols, Assistant Administrator for Air and Radiation, dated October 14, 1994, entitled, ``Part D New Source Review Requirements for Areas Requesting Redesignation to Attainment.'' Michigan has demonstrated that the Flint, Muskegon, Benton Harbor, and Cass County areas will be able to maintain the standard without part D NSR in effect; and therefore, EPA concludes that the State need not have a fully approved part D NSR program prior to approval of the redesignation request. The State's PSD program will become effective in the Flint, Muskegon, Benton Harbor, and Cass County areas upon redesignation to attainment. See rulemakings for Detroit, Michigan (60 FR 1246712468, March 7, 1995); ClevelandAkronLorain, Ohio (61 FR 20458, 2046920470, May 7, 1996); Louisville, Kentucky (66 FR 53665, October 23, 2001); and Grand Rapids, Michigan (61 FR 3183431837, June 21, 1996).

Section 176 conformity requirements. Section 176(c) of the CAA requires states to establish criteria and procedures to ensure that federallysupported or funded activities, including highway projects, conform to the air quality planning goals in the applicable SIPs. The requirement to determine conformity applies to transportation plans, programs and projects developed, funded or approved under Title 23 of the U.S. Code and the Federal Transit Act (transportation conformity) as well as to all other federallysupported or funded projects (general conformity). State conformity revisions must be consistent with federal conformity regulations relating to consultation, enforcement and enforceability, which EPA promulgated pursuant CAA requirements.

EPA believes that it is reasonable to interpret the conformity SIP requirements as not applying for purposes of evaluating the redesignation request under section 107(d) for two reasons. First, the requirement to submit SIP revisions to comply with the conformity provisions of the CAA continues to apply to areas after redesignation to attainment since such areas would be subject to a section 175A maintenance plan. Second, EPA's federal conformity rules require the performance of conformity analyses in the absence of federallyapproved state rules. Therefore, because areas are subject to the conformity requirements regardless of whether they are redesignated to attainment and, because they must implement conformity under federal rules if state rules are not yet approved, EPA believes it is reasonable to view these requirements as not applying for purposes of evaluating a redesignation request. See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001), upholding this interpretation. See also 60 FR 62748, 6274962750 (Dec. 7, 1995) (Tampa, Florida).

EPA approved Michigan's general and transportation conformity SIPs on December 18, 1996 (61 FR 66607 and 61 FR 66609, respectively). Michigan has submitted onhighway motor vehicle budgets of 25.68 tons per day (tpd) VOC and 37.99 tpd NOX for the Flint area, 6.67 tpd VOC and 11.00 tpd NOX for the Muskegon area, 9.16 tpd VOC and 15.19 tpd NOX for the Benton Harbor area, and 2.76 tpd VOC and 3.40 tpd for NOX for the Cass County area based on the areas' projected 2018 emission levels. The Flint, Muskegon, Benton Harbor, and Cass County areas must use the motor vehicle emissions budgets from the maintenance plan in any conformity determination that is effective on or after the effective date of the maintenance plan approval. Thus, the areas have satisfied all applicable requirements under section 110 and part D of the CAA.

b. The Flint, Muskegon, Benton Harbor, and Cass County areas have a fully approved applicable SIP under section 110(k) of the CAA. EPA has fully approved the Michigan SIP for the Flint, Muskegon, Benton Harbor, and Cass County areas under section 110(k) of the CAA for all requirements applicable for purposes of redesignation. EPA may rely on prior SIP approvals in approving a redesignation request (see the September 4, 1992 John Calcagni memorandum, page 3, Southwestern Pennsylvania Growth Alliance v. Browner, 144 F.3d 984, 989990 (6th Cir. 1998), Wall v. EPA, 265 F.3d 426 (6th Cir. 2001)) plus any additional measures it may approve in conjunction with a redesignation action. See 68 FR 25413, 25426 (May 12, 2003). Since the passage of the CAA of 1970, Michigan has adopted and submitted, and EPA has fully approved, provisions addressing the various required SIP elements applicable to the Flint, Muskegon, Benton Harbor, and Cass County areas under the 1hour ozone standard. No Flint, Muskegon, Benton Harbor, or Cass County area SIP provisions are currently disapproved, conditionally approved, or partially approved.
3. The Improvement in Air Quality Is Due to Permanent and Enforceable Reductions in Emissions Resulting From Implementation of the SIP and Applicable Federal Air Pollution Control Regulations and Other Permanent and Enforceable Reductions (Section 107(d)(3)(E)(iii))

EPA finds that Michigan has demonstrated that the observed air quality improvement in the Flint, Muskegon, Benton Harbor, and Cass County areas is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP, federal measures, and other stateadopted measures.

In making this demonstration, the State has calculated the change in emissions between 2002 and 2005, one of the years the Flint, Muskegon, Benton Harbor, and Cass County areas monitored attainment. The reduction in emissions and the corresponding improvement in air quality over this time period can be attributed to a number of regulatory control measures that Michigan and upwind areas have implemented in recent years. The Flint, Muskegon, Benton Harbor, and Cass County areas are all impacted, in varying degrees, by the transport of ozone and ozone precursors from upwind areas. Therefore, local controls as well as controls implemented in upwind counties are relevant to the improvement in air quality in the Flint, Muskegon, Benton Harbor, and Cass County areas.

a. Permanent and enforceable controls implemented. The following is a discussion of permanent and enforceable measures that have been implemented in the areas:

NOX rules. In compliance with EPA's NOX SIP call, Michigan developed rules to control NOX emissions from electric generating units (EGUs), major nonEGU industrial boilers, and major cement kilns. These rules required sources to begin reducing NOX emissions in 2004. From 2004 on, NOX emissions from EGUs have been capped at a statewide total well below pre2002 levels. MDEQ expects that NOX emissions will further decline as the State meets the requirements of EPA's Phase II NOX SIP call (69 FR 21604; April 21, 2004).

Federal Emission Control Measures. Reductions in VOC and NOX emissions have occurred statewide as a result of federal emission control measures, with additional emission reductions expected to occur in the future as the State
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implements additional emission controls. Federal emission control measures include: the National Low Emission Vehicle (NLEV) program, Tier 2 emission standards for vehicles, gasoline sulfur limits, low sulfur diesel fuel standards, and heavyduty diesel engine standards. In addition, in 2004, EPA issued the Clean Air Nonroad Diesel Rule (69 FR 38958 (July 29, 2004)). EPA expects this rule will reduce offroad diesel emissions through 2010, with emission reductions starting in 2008.

Control Measures in Upwind Areas. Upwind ozone nonattainment areas in the Lake Michigan region, including Chicago, Illinois; Gary, Indiana; and Milwaukee, Wisconsin have continued to reduce emissions of VOC and NOX to meet their rate of progress obligations under the 1hour ozone standard. Illinois, Indiana and Wisconsin have all developed regulations to control NOX, Illinois and Indiana pursuant to the NOX SIP call and Wisconsin to meet rate of progress requirements. These upwind reductions in emissions have resulted in lower concentrations of transported ozone entering Michigan. The emission reductions resulting from these upwind control programs are permanent and enforceable.

b. Emission reductions. Michigan is using 2002 for the nonattainment inventory and 2005, one of the years used to demonstrate monitored attainment of the NAAQS, for the attainment inventory. For 2002, MDEQ used the Lake Michigan Air Directors Consortium (LADCO) 2002 base K inventory. This typical summer day inventory was developed by processing emissions data from the EPA final 2002 National Emissions Inventory (NEI). Nonroad emissions were estimated using the most current version of EPA's National Mobile Inventory Model (NMIM). For the 2005 inventory, Michigan interpolated between the 2002 LADCO base K inventory and the LADCO 2009 base K inventory to project emissions for the nonEGU point and area sectors. For EGU emissions, Michigan used 2004 actual emissions as a better representation of 2005 than interpolating from 2009. For nonroad emissions, Michigan used the most current version of NMIM. For onroad emissions, Michigan used the Mobile6.2 model.

Based on the inventories described above, Michigan's submittal documents changes in VOC and NOX emissions from 2002 to 2005 for the Flint, Muskegon, Benton Harbor, and Cass County areas. The emissions reductions for both VOC and NOX, by county and by source category are shown below in Tables 3 through 7.
Table 3.Flint Area: Total VOC and NOX Emissions for Nonattainment Year 2002 (tpd) Genesee Lapeer Total
VOC NOX VOC NOX VOC NOX Point............................. 4.93 2.66 1.14 0.32 6.07 2.98 Area.............................. 22.06 1.76 4.60 0.37 26.66 2.13 Nonroad........................... 33.74 8.72 6.81 2.97 40.55 11.69 Onroad............................ 26.68 40.80 4.84 9.82 31.52 50.62

Total......................... 87.41 53.94 17.39 13.48 104.8 67.42 Table 4.Flint Area: Total VOC and NOX Emissions for Attainment Year 2005 (tpd) Genesee Lapeer Total
VOC NOX VOC NOX VOC NOX Point............................. 4.38 2.61 0.95 0.30 5.33 2.91 Area.............................. 21.63 1.80 4.60 0.38 26.23 2.18 Nonroad........................... 11.79 8.07 6.72 2.79 18.51 10.86 Onroad............................ 17.71 29.98 3.39 6.10 21.10 36.08

Total......................... 55.51 42.46 15.66 9.57 71.17 52.03 Table 5.Flint Area: Comparison of 2002 and 2005 VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2002 2005 (20022005) 2002 2005 (20022005) Point....................... 6.07 5.33 0.74 2.98 2.91 0.07 Area........................ 26.66 26.23 0.43 2.13 2.18 0.05 Onroad...................... 40.55 18.51 22.04 11.69 10.86 0.83 Nonroad..................... 31.52 21.10 10.42 50.62 36.08 14.54

Total................... 104.80 71.17 33.63 67.42 52.03 15.39 [[Page 706]]
Table 6.Muskegon Area (Muskegon County): Comparison of 2002 and 2005 VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2002 2005 (20022005) 2002 2005 (20022005) Point....................... 1.77 1.73 0.04 14.35 13.83 0.52 Area........................ 8.20 8.15 0.05 0.81 0.83 0.02 Onroad...................... 7.67 5.08 2.59 11.93 8.91 3.02 Nonroad..................... 10.41 10.26 0.15 6.48 6.27 0.21

Total................... 28.05 25.22 2.83 33.57 29.84 3.73 Table 7.Benton Harbor Area (Berrien County): Comparison of 2002 and 2005 VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2002 2005 (20022005) 2002 2005 (20022005) Point....................... 1.91 1.93 0.02 3.70 3.47 0.23 Area........................ 9.05 8.99 0.06 0.79 0.81 0.02 Onroad...................... 11.11 7.45 3.66 20.45 14.49 5.96 Nonroad..................... 11.67 10.98 0.69 4.80 4.54 0.26

Total................... 33.74 29.35 4.39 29.74 23.31 6.43 Table 8.Cass County Area: Comparison of 2002 and 2005 VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2002 2005 (20022005) 2002 2005 (20022005) Point....................... 0.31 0.34 0.03 0.20 0.20 0.00 Area........................ 2.22 2.22 0.00 0.20 0.20 0.00 Onroad...................... 2.45 1.66 0.79 4.52 2.97 1.55 Nonroad..................... 5.07 5.06 0.01 2.06 1.92 0.14

Total................... 10.05 9.28 0.77 6.98 5.29 1.69

Table 5 shows that the Flint area reduced VOC emissions by 33.53 tpd and NOX emissions by 15.39 tpd between 2002 and 2005.

Table 6 shows that the Muskegon area reduced VOC emissions by 2.83 tpd and NOX emissions by 3.73 tpd between 2002 and 2005. Table 7 shows that the Benton Harbor area reduced VOC emissions by 4.39 tpd and NOX emissions by 6.43 tpd between 2002 and 2005. Table 8 shows that the Cass County area reduced VOC emissions by 0.77 tpd and NOX emissions by 1.69 tpd between 2002 and 2005.

Based on the information summarized above, Michigan has adequately demonstrated that the improvement in air quality is due to permanent and enforceable emissions reductions.
4. The Areas Have a Fully Approved Maintenance Plan Pursuant to Section 175a of the CAA. (Section 107(d)(3)(E)(iv))

In conjunction with its requests to redesignate the Flint, Muskegon, Benton Harbor, and Cass County nonattainment areas to attainment status, Michigan submitted a SIP revision to provide for the maintenance of the 8hour ozone NAAQS in these areas for at least 10 years after redesignation.

a. What is required in a maintenance plan? Section 175A of the CAA sets forth the required elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. Under section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least ten years after the Administrator approves a redesignation to attainment. Eight years after the redesignation, the State must submit a revised maintenance plan which demonstrates that attainment will continue to be maintained for ten years following the initial tenyear maintenance period. To address the possibility of future NAAQS violations, the maintenance plan must contain contingency measures with a schedule for implementation as EPA deems necessary to assure prompt correction of any future 8hour ozone violations.

The September 4, 1992, John Calcagni memorandum provides additional guidance on the content of a maintenance plan. The memorandum clarifies that an ozone maintenance plan should address the following items: The attainment VOC and NOX emissions inventories, a maintenance demonstration showing maintenance for the ten years of the maintenance period, a commitment to maintain the existing monitoring network, factors and procedures to be used for verification of continued attainment of the NAAQS, and a contingency plan to prevent or correct future violations of the NAAQS.

b. Attainment Inventory. As described above, the MDEQ developed attainment inventories for 2005, one of the years used to demonstrate monitored attainment of the 8hour NAAQS. The 2005 attainment level of emissions is summarized, above, in Tables 4 to 8.

c. Demonstration of Maintenance. Michigan submitted with the [[Page 707]]
redesignation request revisions to the 8hour ozone SIP to include 10 year maintenance plans for the Flint, Muskegon, Benton Harbor, and Cass County areas, as required by section 175A of the CAA. These demonstrations show maintenance of the 8hour ozone standard by assuring that current and future emissions of VOC and NOX for the Flint, Muskegon, Benton Harbor, and Cass County areas remain at or below attainment year emission levels. A maintenance demonstration need not be based on modeling. See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001), Sierra Club v. EPA, 375 F. 3d 537 (7th Cir. 2004). See also 66 FR 53094, 5309953100 (October 19, 2001), 68 FR 25413, 2543025432 (May 12, 2003).

Michigan is using projected inventories developed by LADCO for the years 2009 and 2018. The exception to this is the 2018 onroad mobile source emissions estimates, which were prepared by the Michigan Department of Transportation. Using projected inventories prepared by LADCO will ensure that the inventories used for redesignation are consistent with regional attainment modeling performed in the future. These emission estimates are presented in Tables 9 to 12 below. Table 9.Flint Area: Comparison of 20052018 Total VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2005 2009 2018 20052018 2005 2009 2018 20052018 Point nonEGU................................... 5.27 4.35 4.83 0.44 2.77 2.74 2.81 0.04 Point EGU....................................... 0.06 0.00 0.00 0.06 0.14 0.00 0.01 0.13 Point Total..................................... 5.33 4.35 4.83 0.50 2.91 2.74 2.82 0.09 Area............................................ 26.23 25.65 26.01 0.22 2.18 2.25 2.33 0.87 Onroad.......................................... 21.10 18.18 9.76 11.34 36.08 32.89 11.43 24.65 Nonroad......................................... 18.51 16.35 12.88 5.63 10.86 9.20 15.02 4.16

Total....................................... 71.17 64.01 53.48 17.69 52.03 47.08 22.51 29.52 Safety Margin................................... ........... ........... ........... 17.69 ........... ........... ........... 29.52 Table 10.Muskegon Area: Comparison of 20052018 Total VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2005 2009 2018 20052018 2005 2009 2018 20052018 Point NonEGU................................... 1.63 1.59 2.02 0.39 4.75 4.75 5.14 0.39 Point EGU....................................... 0.10 0.10 0.12 0.02 9.08 6.23 7.17 1.91 Point Total..................................... 1.73 1.69 2.14 0.41 13.83 10.98 12.31 1.52 Area............................................ 8.15 8.09 8.36 0.21 0.83 0.85 0.88 0.05 Onroad.......................................... 5.08 4.66 2.27 2.81 8.91 8.19 2.74 6.17 Nonroad......................................... 10.26 9.52 7.56 2.70 6.27 5.84 4.73 1.54

Total....................................... 25.22 23.96 20.33 4.89 29.84 25.86 20.66 9.18 Safety Margin................................... ........... ........... ........... 4.89 ........... ........... ........... 9.18 Table 11.Benton Harbor Area (Berrien County): Comparison of 20052018 Total VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2005 2009 2018 20052018 2005 2009 2018 20052018 Point NonEGU................................... 1.93 1.95 2.40 0.47 3.47 3.17 3.22 0.25 Point EGU....................................... 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Point Total..................................... 1.93 1.95 2.40 0.47 3.47 3.17 3.22 0.25 Area............................................ 8.99 8.92 9.38 0.39 0.81 0.83 0.86 0.05 Onroad.......................................... 7.45 6.54 3.44 4.01 14.49 13.27 4.57 9.92 Nonroad......................................... 10.98 9.86 7.77 3.21 4.54 4.01 2.86 1.68

Total....................................... 29.35 27.27 22.99 6.36 23.31 21.28 11.51 11.80 Safety Margin................................... ........... ........... ........... 6.36 ........... ........... ........... 11.80 [[Page 708]]
Table 12.Cass County Area: Comparison of 20052018 VOC and NOX Emissions (tpd) VOC NOX
Sector Net change Net change 2005 2009 2018 20052018 2005 2009 2018 20052018 Point nonEGU................................... 0.34 0.39 0.49 0.15 0.20 0.20 0.23 0.03 Point EGU....................................... 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Point Total................................. 0.34 0.39 0.49 0.15 0.20 0.20 0.23 0.03 Area............................................ 2.22 2.22 2.31 0.44 0.20 0.21 0.22 0.02 Onroad.......................................... 1.66 1.47 0.74 9.64 2.97 3.03 0.94 2.03 Nonroad......................................... 5.06 4.70 3.50 3.59 1.92 1.67 1.17 0.75

Total....................................... 9.28 8.78 7.04 2.24 5.29 5.11 2.56 2.73 Safety Margin................................... ........... ........... ........... 2.24 ........... ........... ........... 2.73

The emission projections show that MDEQ does not expect emissions in the Flint, Muskegon, Benton Harbor, and Cass County areas to exceed the level of the 2005 attainment year inventory during the maintenance period. In the Flint area, MDEQ projects that VOC and NOX emissions will decrease by 17.69 tpd and 29.52 tpd, respectively. In the Muskegon area, MDEQ projects that VOC and NOX emissions will decrease by 4.89 tpd and 9.18 tpd, respectively. In the Benton Harbor area, MDEQ projects that VOC and NOX emissions will decrease by 6.36 tpd and 11.80 tpd, respectively. In the Cass County area, MDEQ projects that VOC and NOX emissions will decrease by 2.24 tpd and 2.73 tpd, respectively.

As part of its maintenance plan, the State elected to include a ``safety margin'' for the areas. A ``safety margin'' is the difference between the attainment level of emissions (from all sources) and the projected level of emissions (from all sources) in the maintenance plan which continues to demonstrate attainment of the standard. The attainment level of emissions is the level of emissions during one of the years in which the area met the NAAQS. The Flint, Muskegon, Benton Harbor, and Cass County areas attained the 8hour ozone NAAQS during the 20042006 time period. Michigan used 2005 as the attainment level of emissions for the areas. For Flint, the emissions from point, area, nonroad, and mobile sources in 2005 equaled 71.17 tpd of total VOC. MDEQ projected VOC emissions out to the year 2018 to be 53.48 tpd of total VOC. The SIP submission demonstrates that the Flint area will continue to maintain the standard with emissions at this level. The safety margin for VOC is calculated to be the difference between these amounts or, in this case, 17.69 tpd of total VOC for 2018. By this same method, 29.52 tpd (i.e., 52.03 tpd less 22.51 tpd) is the safety margin for NOX for 2018. For the Muskegon area, 4.89 tpd and 9.18 tpd are the safety margins for VOC and NOX, respectively. For the Benton Harbor area, 6.36 tpd and 11.80 tpd are the safety margins for VOC and NOX, respectively. For the Cass County area, 2.24 tpd and 2.73 tpd are the safety margins for VOC and NOX, respectively. The safety margin, or a portion thereof, can be allocated to any of the source categories, as long as the total attainment level of emissions is maintained.

d. Monitoring Network. Michigan currently operates two ozone monitors in the Flint area, and one ozone monitor each in Muskegon, Benton Harbor, and Cass County areas. MDEQ has committed to continue operating and maintaining an approved ozone monitor network in accordance with 40 CFR part 58.

e. Verification of Continued Attainment. Continued attainment of the ozone NAAQS in the Flint, Muskegon, Benton Harbor, and Cass County areas depends, in part, on the State's efforts toward tracking indicators of continued attainment during the maintenance period. The State's plan for verifying continued attainment of the 8hour standard in the Flint, Muskegon, Benton Harbor, and Cass County areas consists of plans to continue ambient ozone monitoring in accordance with the requirements of 40 CFR part 58. In addition, MDEQ will periodically review and revise if necessary the VOC and NOX emissions inventories for the Flint, Muskegon, Benton Harbor, and Cass County areas, as required by the Consolidated Emissions Reporting Rule (40 CFR part 51), to track levels of emissions in the future.

f. Contingency Plan. The contingency plan provisions are designed to promptly correct or prevent a violation of the NAAQS that might occur after redesignation of an area to attainment. Section 175A of the CAA requires that a maintenance plan include such contingency measures as EPA deems necessary to assure that the state will promptly correct a violation of the NAAQS that occurs after redesignation. The maintenance plan should identify the contingency measures to be adopted, a schedule and procedure for adoption and implementation of the contingency measures, and a time limit for action by the state. The state should also identify specific indicators to be used to determine when the contingency measures need to be adopted and implemented. The maintenance plan must include a requirement that the state will implement all measures with respect to control of the pollutant(s) that were contained in the SIP before redesignation of the area to attainment. See section 175A(d) of the CAA.

As required by section 175A of the CAA, Michigan has adopted a contingency plan for the Flint, Muskegon, Benton Harbor, and Cass County areas to address possible future ozone air quality problems. The contingency plan adopted by Michigan has two levels of response, depending on whether a violation of the 8hour ozone standard is only threatened (Action Level Response) or has occurred (Contingency Measure Response).

An Action Level Response will occur when a twoyear average fourth high monitored daily peak 8hour ozone concentration of 85 ppb or higher is monitored within an ozone maintenance area. An Action Level Response will consist of Michigan performing a review of the circumstances leading to the high monitored values. MDEQ will conduct this review within six months following the close of the ozone season. If MDEQ determines that contingency measure implementation is necessary to prevent a future violation of the NAAQS, MDEQ will select and implement a measure that can be implemented promptly.

A Contingency Measure Response will be triggered by a violation of the standard (a 3year average of the annual
[[Page 709]]
fourthhighest daily maximum 8hour average ozone concentration of 85 ppb or greater). When a Contingency Measure Response is triggered, Michigan will select one or more control measures for implementation. The timing for implementation of a contingency measure is dependent on the process needed for legal adoption and source compliance which varies for each measure. MDEQ will expedite the process of adopting and implementing the selected measures, with a goal of having measures in place as expeditiously as practicable within 18 months. EPA is interpreting this commitment to mean that the contingency measure will be adopted and implemented within 18 months.

Contingency measures contained in the maintenance plans are those emission controls or other measures that Michigan may choose to adopt and implement to correct possible air quality problems. These include the following:

i. Lower Reid vapor pressure gasoline requirements;

ii. Reduced VOC content in Architectural, Industrial, and Maintenance (AIM) coatings rule;

iii. Auto body refinisher selfcertification audit program;

iv. Reduced VOC degreasing rule;

v. Transit improvements;

vi. Diesel retrofit program;

vii. Reduced VOC content in commercial and consumer products rule;

viii. Reduce idling program.

g. Provisions for Future Updates of the Ozone Maintenance Plan. As required by section 175A(b) of the CAA, Michigan commits to submit to the EPA an updated ozone maintenance plan eight years after redesignation of the Flint, Muskegon, Benton Harbor, and Cass County areas to cover an additional 10year period beyond the initial 10year maintenance period. Michigan has committed to retain the control measures for VOC and NOX emissions that were contained in the SIP before redesignation of the areas to attainment, as required by section 175(A) of the CAA.

EPA has concluded that the maintenance plan adequately addresses the five basic components of a maintenance plan: attainment inventory, maintenance demonstration, monitoring network, verification of continued attainment, and a contingency plan. The maintenance plan SIP revision submitted by Michigan for the Flint, Muskegon, Benton Harbor, and Cass County areas meets the requirements of section 175A of the CAA.
ii. Adequacy of Michigan's Motor Vehicle Emissions Budgets (MVEBs) 1. How Are MVEBs Developed and What Are the MVEBs for the Flint, Muskegon, Benton Harbor, and Cass Areas?

Under the CAA, states are required to submit, at various times, control strategy SIP revisions and ozone maintenance plans for ozone nonattainment areas and for areas seeking redesignations to attainment of the ozone standard. These emission control strategy SIP revisions (e.g., reasonable further progress SIP and attainment demonstration SIP revisions) and ozone maintenance plans create MVEBs based on onroad mobile source emissions for criteria pollutants and/or their precursors to address pollution from cars and trucks. The MVEBs are the portions of the total allowable emissions that are allocated to highway and transit vehicle use that, together with emissions from other sources in the area, will provide for attainment or maintenance.

Under 40 CFR part 93, a MVEB for an area seeking a redesignation to attainment is established for the last year of the maintenance plan. The MVEB serves as a ceiling on emissions from an area's planned transportation system. The MVEB concept is fur

FOR FURTHER INFORMATION CONTACT Charles Hatten, Environmental Engineer, Criteria Pollutant Section, Air Programs Branch (AR18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 8866031, hatten.charles@epa.gov.