Additional Options Considered for

"Proposed Rule to Implement the 8-Hour Ozone National Ambient Air Quality Standard."

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Research Triangle Park, NC

March 2003

INTRODUCTION

In a separate notice of proposed rulemaking, EPA is proposing two discrete alternative frameworks to implement the 8-hour ozone national ambient air quality standard (NAAQS or standard). The EPA is proposing this rule so that States may know which statutory requirements apply for purposes of developing State implementation plans (SIPs) under the Clean Air Act (CAA or Act) to implement the 8-hour ozone NAAQS. The intended effect of this rule is to provide certainty to States regarding their planning obligations such that States may begin SIP development upon designation and classification for the 8-hour standard.

Following are the principles that guided EPA in the development of these proposed frameworks to implement the 8-hour ozone standard: 1) In order to protect public health, provide incentives for expeditious attainment of the 8-hour ozone standard and avoid incentives for delay; 2) Provide reasonable but expeditious attainment deadlines; 3) Have a basic, straightforward structure that can be communicated easily; 4) Provide flexibility to States and EPA on implementation approaches and control measures while ensuring that the implementation strategy is supported by the CAA; 5) Emphasize national and regional measures to help areas come into attainment and, where possible, reduce the need for those local controls that are more expensive than national and regional measures; and 6) Provide a smooth transition from implementation of the 1-hour ozone NAAQS to 8-hour ozone NAAQS implementation.

As noted in that proposal, EPA originally intended to implement the 8-hour ozone standard in a more flexible approach under subpart 1 of part D, Title I of the CAA. This would have allowed areas more flexibility to determine whether to regulate NOx, VOC or both to address ozone nonattainment.

As also noted in that proposal, however, the Supreme Court determined that an approach that ignored subpart 2 was unreasonable. In structuring a proposed implementation rule, EPA has tried to stay as close as possible to the principles noted above, particularly with regard to seeking flexible ways for States to address their 8-hour ozone problems by avoiding mandatory measures that may be unreasonable for an area. EPA has spent a large amount of time investigating possible legal theories and policy options to find flexibility within the Supreme Court's decision. EPA has also had the benefit of ideas and recommendations from many interested stakeholders, who also have spent much time developing their own theories and ideas. Based on these efforts, EPA believes that it has developed options for an implementation program that is workable under the constraints of the CAA. Nonetheless, EPA recognizes that those constraints will still require a number of areas to adopt certain control measures that may not be as effective as others in achieving the 8-hour ozone standard. In the proposed rule, EPA is soliciting any further ideas for addressing this situation.

To describe EPA's proposed frameworks for implementing the 8-hour ozone standard, it was necessary to examine all the components or elements of the process used to implement the standard. Therefore, the issues and options that EPA is proposing that deal with the aspects of preparing SIPs for the standard are presented individually in the proposed rulemaking. In the proposal, EPA is soliciting comments on the approach for each of the elements and on two distinct frameworks that combine options from each of the implementation elements.

The proposed rulemaking describes only those options or approaches EPA is proposing. The EPA considered a number of other options and approaches for some of the implementation elements, some of which were suggested in oral or written comments at the public meetings EPA held on implementing the 8-hour standard, or in written comment, or other stakeholder meetings or conversations. These other options that EPA considered but that are not being proposed are described in this document, which is being made available in the docket for the rulemaking.

ISSUE: How will EPA reconcile Subparts 1 and 2? How will EPA classify nonattainment areas for the 8-hour standard? What attainment dates would apply?

Other Options EPA considered

At the three public meetings EPA held in March and April of 2002, EPA presented four classification options. As a result of the feedback we received at those meetings and in written comments, and after further deliberation, our proposal above includes two of the four public meeting options, and we have combined the concept of one of the other four into the incentive feature proposed above. Under the one option not being proposed at all, EPA would have used an area's most recent 1-hour ozone design value at the time of designation to establish the area's classification for the 8-hour NAAQS. While this option would have allowed for use of the classification table as set forth in section 181, EPA concluded (and many members of the public agreed) that this approach was not representative of each area's 8-hour ozone problem.

At the public meetings and in written comments, several other options were suggested, which EPA considered in formulating this proposal; these are discussed below.

Classification based on the most recent 1-hour ozone design value. This option would implement subpart 2 classification provision in table 1 as written, using an area's current 1-hour ozone design values rather than their 8-hour design values. Under this option, some areas (i.e., those whose 1-hour design values were .121 ppm or greater) would be classified under subpart 2. However, more than half the hypothetical nonattainment areas would be covered under subpart 1, since their design values fall below .121 ppm, the minimum value in table 1. This option would provide flexibility in implementation for those areas covered under subpart 1. An area's 1-hour design value, however, may not reflect the area's 8-hour O3 problem and would produce some inequities (e.g., aN area covered under subpart 1 may have a higher 8-hr ozone design value than another area that is marginal or even moderate and covered under subpart 2). This option received mostly adverse comment at the public meetings due to the fact that 1-hour design values do not reflect 8-hour ozone problems in many cases.

Implement the 8-hour standard in a sequential manner. Under this option, areas that are currently designated nonattainment under the 1-hour standard would continue to implement their SIP under subpart 2 until they reached a certain trigger. Two potential triggers were suggested–either attainment of the 1-hour standard or implementation by the area of all measures under subpart 2. Only after the appropriate trigger would the area be classified for the 8-hour standard and subject to planning obligations for the 8-hour standard. All areas would be classified under subpart 1 for the 8-hour standard, although the "textually applicable" subpart 2 requirements would continue to apply for the implementation of the 8-hour standard. (A commenter provided an example of "textually applicable" subpart 2 requirements: those requirements that have not been exhausted and can be applied without rewriting them to make them comport with a revised standard, such as the requirements for ozone transport under section 184.) EPA believes that the CAA as interpreted by the Supreme Court, does not permit such an interpretation. Under section 107 of the CAA (and under other statutory amendments and provisions), EPA is given a limited amount of time to designate nonattainment areas under the 8-hour ozone standard. Once an area is designated nonattainment under the 8-hour standard, subpart 1 provides areas with a limited amount of time to develop and submit an implementation plan. The option proposed by the commenter fails to account for this timing. Moreover, the Supreme Court clearly stated that it interprets subpart 2 to provide classifications for areas designated nonattainment for the 8-hour NAAQS. Under this approach, no areas would be classified subpart 2 for the 8-hour NAAQS.

Classify all areas under subpart 2 and place a higher percentage of 8-hour ozone nonattainment areas into higher classifications to reflect the fact that the 8-hour standard is more stringent than the 1-hour standard. The commenter did not suggest a mechanism for determining which areas would fall into each classification. One of the options being proposed (Option 1) would place all 8-hour ozone NAAQS nonattainment areas in subpart 2 based on the percentage an area's design value is above the standard (the same percentages used in the section 181 table for the 1-hour design values in relation to the 1-hour standard). EPA does not believe that it is appropriate to place areas in higher classifications simply to reflect the fact that the 8-hour standard is more stringent. Rather, as Congress did in 1990, EPA believes it is more appropriate to classify areas based on the difficulty of that area to attain the NAAQS and the time it takes to attain, as indicated in a relative sense by the area's design value. Thus, if an area should be able to adopt controls to attain within 6 years after designation, it should not be classified as severe.1

Another commenter suggested an approach that would have a similar result – revise table 1 to reflect the spread of 8-hour design values that exist at the time of designations and classifications. In other words, table 1 reflected the spread of 1-hour ozone design values for nonattainment areas at the time the Amendments were enacted –from just above 0.12 ppm to well above 0.280 ppm. In 2000, the nonattaining 8-hour ozone design values range from above 0.08 ppm to 0.146 ppm. For the reasons provided above, EPA does not believe that this approach reflects the level of control needed for areas to attain the 8-hour NAAQS nor the time it will take the areas to attain the standard. Looking back at the 8-hour design values that existed at the time EPA originally classified areas under the 1990 CAAA, the 8-hour design values ranged to 0.205 ppm for the period 1986-1988 and 0.192 ppm for the period 1987 to1989. (Therefore, for example, there would have been one area classified extreme if the 8-hour standard existed at that time.)

Only Areas Currently Subject to Subpart 2 Would Be Classified Under Subpart 2. Another commenter suggested that only areas that are currently designated nonattainment for the 1-hour ozone NAAQS be subject to subpart 2 and all other "new" areas be subject only to subpart 1. In practice, this approach would produce similar, though not identical, results to EPA's option 2 in which EPA will rely on an area's most recent design value for the 1-hour standard in determining whether it should be subject to subpart 1 or subpart 2. We believe that the Option 2 provides a more balanced method for determining which areas are subject to the planning requirements of subpart 2 because it considers actual air quality data rather than simply looking to see whether an area is currently under the subpart 2 scheme or not.

Distribute Areas in the Subpart 2 Classification Based on Distribution In 1990. One commenter suggested that we use the same distribution of areas in each classification that existed for the designations and classifications that occurred immediately after the 1990 CAA Amendments. Under this option, for example, if 10 percent of the areas designated nonattainment were classified as severe-15 in1990, then 10 percent of the current nonattainment areas would be placed in that classification. We do not believe that this comports with Congressional intent. We find no evidence that Congress intended to include a specific percentage of areas in each of the 5 subpart 2 classifications following the 1990 Amendments. Rather, we believe Congress looked closely at the air quality in the areas, determined which areas would need more controls – and ths more time – to reach attainment, and grouped the areas accordingly. Thus, Congress required areas that needed more time to attain to adopt more stringent controls. Similarly, EPA believes it is appropriate to link the classifications to how far above the standard an area's design value is. As a general rule, EPA believes this is the best indication of the level of control that will be needed to bring an area into attainment and the time it will take such area to attain the standard. Moreover, if a State believes that an area will need more time to attain because the classification does not accurately reflect the area's ozone problem, the State can request EPA to give that area a higher classification.

Other methods for translating section 181's Table 1 from 1-hour to 8-hour ozone design values:

Other translations were considered but in EPA's opinion do not have the same degree of consonance with the intent of Congress when it enacted subpart 2. EPA is therefore not proposing these per se, but in the notice of proposed rulemaking, EPA is soliciting comment on the merits of them. If there is sufficient interest in any of these translations, EPA will consider publishing a supplemental proposal on them.

–Establishing a relationship between the 1-hour and 8-hour monitored values or design values based on measured air quality data:

Any attempt to derive a scientific relationship between 1-hour values and 8-hour values would result in a relationship that does not fit all situations.2

The other problem with trying to establish a relationship between monitored 1-hour and 8-hour ozone levels for purposes of translating the classification table is that what might be a better fit for one area may not be as good a fit for other areas. Also, EPA does not believe that Congress intended different threshold schemes to apply for different areas. However, using a relationship derived from data for the entire country would also likely have more scatter than data derived for individual areas.

In addition, the effect of using a relationship between historical 1-hour and 8-hour ozone data to establish the translation of table 1 would likely result in a larger number of areas in the higher subpart 2 classifications, which would further limit an area's flexibility in crafting control measures appropriate to the area's problems.

EPA therefore believes there is no obvious "correct" technical method for performing the translation. Thus, EPA believes it is best to rely on what appeared to be Congress's intent in developing a proper translation for purposes of applying section 181's Table 1 to the 8-hour ozone standard. EPA solicits comment, however, on other ways of interpreting Congressional intent and on the methods described in this proposal. It should be noted that the translation being proposed (based on the percentages above the standard) does establish a de facto relationship between 1-hour values and the 8-hour values that is not based on measured air quality values.

–Construct a revised classification table (Table 1 of subpart 2) based on the 8-hour ozone values used in EPA's Air Quality Index (AQI). The AQI3 levels are designed to trigger immediate actions that will keep an area from reaching short-term levels that approach the level considered to cause significant harm to the health of persons.4 The levels in the AQI are as follows:

AQI Value	Category	8-hr (or 1-hr) O3 concentration (ppm)
0 to 50	Good	up to 0.064
51 to 100	Moderate	0.065 up to 0.084
101 to 150	Unhealthy for Sensitive Groups	0.085 up to 0.104
151 to 200	Unhealthy	0.105 up to 0.124
201 to 300	Very unhealthy	0.125 up to 0.374
301 to 500	Hazardous	0.0405 up to 0.604 (1-hr)

These levels were not designed to classify areas for purposes of developing longer range plans for achieving the ozone NAAQS. For one thing, the values provide are not design values (i.e., they are not designed to show a direct relationship between the air quality of an area in relation to the standard itself, which is based upon data over a 3-year period), but are short-term exposure values (either single 8-hour or single 1-hour concentrations), intended to provide thresholds on a realtime basis for health advisories to the general public or rapid control action by the air pollution control agency. Therefore EPA does not consider them appropriate for the purpose of classifying areas to establish longer-range emission control programs and establish attainment dates.

ISSUE: How will EPA transition from the 1-hour to the 8-hour standard?

Other Options EPA considered

EPA considered an option in which EPA would revoke the 1-hour ozone standard at the time EPA finds the area's motor vehicle emissions budget under the 8-hour standard to be adequate. EPA's transportation conformity rules allow EPA to find a nonattainment area's emissions budget adequate before actually approving the attainment demonstration and/or reasonable further progress provisions of the SIP on which the budget is based. Of course, EPA can only find a budget adequate if it has a reasonable expectation that the attainment demonstration and/or reasonable further progress provision is adequate. This approach would result in revocation of the 1-hour standard sometime after the timing in the first option described above as the adequacy process occurs only after the area has submitted a SIP as required in response to its designation and classification. Conformity would apply under both standards from 1 year following the effective date of the nonattainment designation for the 8-hour standard and until a conformity budget for the 8-hour ozone attainment demonstration and/or reasonable further progress provision is determined adequate. At the time of the adequacy determination, EPA would revoke the 1-hour standard.

This approach raises a practical concern about implementing both standards simultaneously. For instance, transportation conformity would apply for both standards for some period of time. Until a new budget is established under the 8-hour standard, the area would have to meet not only the current budget for the 1-hour SIP, but also either pass the build/no-build or the no-
greater-than baseline conformity test, which generally may be more difficult for an area to meet. Also, for 8-hour ozone nonattainment areas that are larger than – but encompass – 1-hour ozone nonattainment areas, the transportation conformity requirements would likely have to be met individually for both standards–for the 8-hour standard in the larger area and for the 1-hour standard in the area that comprised the 1-hour ozone nonattainment area; this would add complexity to the process.

Because of this practical concern, EPA is not proposing the above approach. A number of commenters at EPA's public meetings and in written comments favored this approach.

In addition, EPA presented other options at the public meetings and received suggestions for additional options, but did not believe these would ensure a smooth transition from the 1-hour standard to the 8-hour ozone standard, particularly in light of concerns about conformity.

•	An option whereby EPA would revoke the 1-hour standard at the time of 8-hour O3 attainment/nonattainment designation would ensure a quick transition to the 8-hour standard, but there would be a gap in conformity coverage during the 1-year grace period after designation of the 8-hour ozone standard.

•	An option whereby EPA would revoke the 1-hour standard for all purposes at the time EPA determines that the area meets the 1-hour O3 NAAQS (after 8-hour O3 designation). This approach also would create a situation under which conformity would apply to both standards for areas that remain covered by the 1-hour standard after the first year following nonattainment designations under the 8-hour standard. As noted in the proposal, however, EPA is also soliciting comment on this approach, even though we are not proposing it.

•	An option whereby EPA would revoke the 1-hour standard at the time of approval of 8-
hour O3 SIPs (for 8-hour O3 nonattainment areas), which would ensure that attainment plans and control measures would be in place under the 8-hour standard before the 1-hour standard is revoked. EPA believes this option is unreasonable because it would result in conformity and new source review applying simultaneously for both standards for a number of years as SIPs generally would be due around three years following designation and EPA approval could take up to 18 months.

•	An option whereby EPA would revoke the 1-hour ozone standard at the time the State SIP rules are enforceable at the State level with some preliminary assessment by EPA that the SIP is approvable. While, compared with the previous option, this option would reduce the amount of time that conformity and NSR would apply simultaneously for the two standards, EPA believes that it is unreasonable for the same reason.

ISSUE: Should prescribed requirements of Subpart 2 apply in all 8-hour nonattainment areas classified under subpart 2, or is there flexibility to apply equivalent measures, or drop some requirements altogether if in certain narrowly defined circumstances they are determined to be inappropriate?

EPA considered the following options and obtained input on them at the three public meetings.

Option 1. Assume no changes can be made to the statutory requirements of subpart 2.

Option 2. Identify a legal justification to allow areas covered under subpart 2 to substitute measures that will provide equivalent ozone reductions.

Option 3. Identify a legal justification to allow EPA to determine on a case-by-case basis which of the mandatory control measures under subpart 2 can be waived by the State in preparation of its attainment demonstration. The area would still have to provide controls sufficient to attain the standard by the attainment date for its classification.

Option 4. Review each of the individual control requirements in subpart 2 to determine what, if any flexibility may be provided for that specific requirement (e.g., can the 15 percent VOC reduction requirement be deemed to have been met for areas that have already achieved a 15 percent reduction in VOC reductions for the 1-hour standard? For serious and above areas, can EPA determine that onboard vapor recovery is in widespread use and thus, under section 202(a)(6) revise or waive the stage II requirement for those areas?)

In the notice of proposed rulemaking, EPA is proposing that subpart 2 requirements would apply to all areas covered under subpart 2 consistent with the area's classification. In that respect EPA's proposal is similar to the former Option 1 described above. EPA is proposing also to consider allowing case-by-case waivers of specific subpart 2 requirements when sufficient evidence is presented that absurd results that would occur through compliance with the specific subpart 2 requirement. In that respect, EPA's proposal is similar to the former options 2 and 3 above.

With regard to Option 4, EPA has considered whether the 15 percent rate of progress requirement for VOC emission reductions for the first 6 years after a nonattainment designation could be interpreted to require only 3 percent reduction per year of either VOC or NOx or both if the area had already accomplished such reductions for the period 1990 to 1996. EPA is proposing this option in the section on reasonable further progress. The EPA is still evaluating whether the stage II vapor recovery provisions in the Clean Air Act (sections 182(b)(3) (which applies to serious and above nonattainment areas) and 184 (b)(2) (which applies to the Ozone Transport Region) can be waived or revised to account for the increasing use over time of onboard refueling vapor recovery (ORVR) systems.

ISSUE: How will EPA address transport of ground-level ozone and its precursors when implementing the 8-hour ozone standard?

EPA had considered alternative options for several issues related to transport.

Issue: Who should conduct the analysis to evaluate the extent, causes and solution to transport of ground-level ozone and its precursors?

One option that EPA considered is a combination of EPA and State activities. EPA would perform regional scale modeling to evaluate the impacts of regional transport and identify measures (e.g,. state-level emission caps or other requirements) sufficient to eliminate a State's significant contribution to areas in downwind States (as in option 1). As part of this analysis, EPA would make a determination as to whether these steps resolve the transport problem. If not, the EPA would identify areas for which additional analyses, which may include photochemical grid modeling, will be needed as part of the State's attainment demonstration SIP. EPA would issue technical guidance on analytical techniques and analyses still needed to address the remaining portion of the transport problem. These analyses would include assessment of the States' emissions impacts on areas in downwind States and could include identification of additional control measures needed to eliminate the significant contributions to areas in downwind States. EPA guidance will provide a description of the role of transport, how ozone is formed in the atmosphere, chemistry, mixing turbulence and transport, models to review transport, and guidance describing ways to evaluate transport and address downwind influence on downwind areas. This option may require States to work together as described in the sections on attainment demonstrations. In developing an attainment SIP for their local area, states would be allowed to rely on anticipated upwind reductions to be achieved by measures based on the regional scale modeling. Because states are working together, they should agree on both the need for upwind emission reductions and on adopting controls in sufficient time for the downwind areas to meet their attainment dates.

Another option that EPA considered but is not proposing is that States would, either alone or by forming multi-state groups, perform the regional scale modeling to assess each State's contribution to other areas and identify equitable control measures throughout the region that eliminate their significant contribution. In developing an attainment SIP for their local area, states would be allowed to rely on anticipated upwind reductions to be achieved by measures based on the regional scale modeling.

The EPA did not propose either of these options for several reasons. One reason is that the significant amount of time it would take for States to organize and perform the necessary modeling would likely preclude having usable results in the timeframes needed. Another reason is the fact that there would likely be significant differences from region to region in assessment of transport and the manner in which it would be addressed. EPA believes that the approach discussed in the proposed rulemaking would be more effective in addressing transport.

Issue: Can the nonattainment designation process be used to address transport?

EPA has considered, but is not proposing, an option that would rely solely on the air quality designations process in section 107 of the CAA to address regional transport. For example, some commenters suggested at the public meeting that EPA could designate large enough nonattainment areas to include both the violating and contributing areas and coordinate attainment dates within the area such that the upwind contributing and downwind nonattainment areas reflect the same attainment date. This approach could result in very large nonattainment areas. The EPA is not proposing this option for several reasons. First, EPA believes that this approach does not square with the definition of a nonattainment area in section 107(d)(1)(A) which provides for including "nearby" areas that contribute to nonattainment. The EPA does not believe that this provision was intended to address long-range transport. Second, as a policy matter, EPA believes it would not be productive to subject broad areas of the country to nonattainment programs such as new source review and conformity.

For similar reasons, EPA also is not considering establishing new ozone transport regions as provided under section 126(a). While some commenters suggested this approach at the public meeting, other participants strongly opposed the approach.

ISSUE: What requirements for reasonable further progress (RFP) should apply under the 8-hour ozone standard?

The EPA considered, but is not proposing, alternative options for several of the RFP issues as follows:

For subpart 2 areas, should the initial 15 percent RFP requirement be limited to VOC emissions?

Other options that EPA considered

A number of commenters wanted EPA to provide a more flexible approach for RFP. One recommendation was to allow more NOx emission reductions to be substituted for VOC emission reductions for the 15 percent requirement. Another recommendation was to allow areas to reduce emissions of whatever precursor (i.e., VOC and/or NOX) and by whatever amount is necessary to reach attainment by attainment date. In other words, the commenter was suggesting that EPA not apply the ROP provisions in section 182 and not prescribe what RFP means under subpart 1. EPA has not been able to identify a legal rationale to accommodate such recommendations in light of statutory requirements.

What baseline year should be required for the emission inventory for the RFP requirement

Other Options EPA considered

EPA presented other options for the baseline year at the public meetings. One option would be to use 1990–the year specified in the CAA. Those present at the public meetings had a mixed response regarding the use of 1990 as the baseline year of emission inventory. Use of 1990 as the baseline would allow States to take credit for measures they adopt and implement after 1990. However, 1990 would be an older inventory and does not reflect current circumstances. Moreover, there are newer, more refined tools and techniques used to determine inventories. Some commenters have indicated that developing a good 1990 base year inventory would be technically difficult for those areas that were not nonattainment for the 1-hour standard and thus had not developed inventories for that year. Others indicated it would be possible for some areas to develop a good 1990 emissions inventory. Also suggestions were made to consider use of some other year, e.g., 1999 since it is a relatively recent year with an updated quality-assured emission inventory. EPA rejected these other options because the 2002 base year appeared to be the most appropriate year in light of anticipated availability of current information at the time States will be preparing the RFP provisions of their implementation plans.

How should the RFP requirements be implemented for areas designated for the 8-hour ozone standard that entirely or in part encompass an area that was designated nonattainment for the 1-
hour ozone standard?

Other Options EPA considered

The other option EPA considered was to develop a new baseline and new RFP emission reduction targets for the entire area, but in addition retain current RFP for the 1-hour ozone NAAQS.

This option would allow the entire area to make progress toward attainment of the 8-hour ozone NAAQS while preserving the adopted ROP plan for the current 1-hour standard nonattainment area. It would establish two ROP targets-–one for the area that was subject to the 1-hour standard and one for the entire 8-hour ozone nonattainment area. This option was not selected since it appeared unnecessary to ensure progress toward attainment.

Other Issue EPA Considered

Should EPA use the RFP requirement to address an upwind State's responsibility under section 110(a)(2)(D), which requires that the SIP provide for preventing a significant contribution to a downwind jurisdiction's nonattainment situation?

One of the problems identified by commenters is that transport of ozone and its precursors from emission sources in one or more nonattainment areas in an upwind State may prevent an area in a downwind State from attaining the standard by its attainment date unless the upwind area has the same or an earlier attainment date. The EPA's proposed approach for addressing long-range transport of ozone and its precursors is described in the notice of proposed rulemaking.

Under the subpart 2 classification and attainment date structure, a source's emissions from a nonattainment area with a particular classification and attainment date may contribute to nonattainment in a downwind area with a lower classification and therefore an earlier attainment date. The downwind area (for example, a marginal area) may not be able to reach attainment by its mandated attainment date until the upwind area (for example, a moderate or above area) achieves most or all of its emissions reductions, which it would normally not achieve until close to its attainment date. One comment letter from a State air pollution control agency suggested that EPA rely on the RFP requirement to ensure early reductions in areas in upwind States. Based on this idea, EPA considered an approach under which the area in an upwind State with the later attainment date would be required to achieve greater emissions reductions for its RFP plan from sources that contribute to nonattainment in the downwind State's area on a tighter schedule (namely by the nonattainment date of the downwind State's area) than that required for reductions from other sources needed to attain the standard within the upwind area by the attainment date of the upwind State's area. This additional RFP constraint would therefore assist the downwind State's area in attaining the standard by its attainment date even if it were subject to transport from an upwind State's nonattainment area. This approach would apply to nonattainment areas in upwind States that EPA identifies under section 110(a)(2)(D) as contributing significantly to nonattainment or interfering with maintenance in another State. Of course, this proposed RFP constraint would likely not be sufficient to wholly address significant interstate transport; EPA's approach for addressing this is discussed elsewhere in this notice of proposed rulemaking.

This approach could partially addresses the problem of mismatched attainment dates in areas affected by transport and therefore proposes it for comment.

The EPA decided not to propose this option at this time because we could not identify a possible legal rationales supporting this option.

ISSUE: Will EPA be contemplating incentives for areas that want to take early action for reducing ozone under the 8-hour standard?

EPA considered a transitional classification as a means for encouraging States to take early action for implementing the 8-hour ozone NAAQS. EPA does not consider this approach to be feasible.

On July 16, 1997, the President issued a directive to EPA on the implementation of the revised air quality standards for ozone and PM. On November 17, 1998, EPA issued draft guidance for implementing the revised ozone and PM NAAQS and the regional haze program consistent with the Clean Air Act and the President's Directive ("Implementation of Revised Air Quality Standards for Ozone and Particulate Matter," 62 FR 38421, July 18, 1997). Consistent with the Presidential Directive, the draft guidance provided for the creation of a transitional classification for certain areas. This classification was intended to be made available only to areas with air quality meeting the1-hour ozone standard, but not meeting the more stringent 8-
hour ozone standard. At that time, the transitional classification was the primary element of EPA's flexible implementation approach for ozone. This classification encouraged cleaner air sooner, responded to the fact that ozone is a regional as well as a local problem, and eliminated unnecessary planning and regulatory burdens for State and local governments.

Since the November 17, 1998, guidance was issued, however, the legislative authority that EPA proposed to use as the basis for implementing the 8-hour standard was challenged, calling into question the legality of the transitional classification as a means of providing flexible implementation for areas covered under subpart 2, Part D, Title I of the CAA. (The legislative authority for the nonattainment area provisions is found in the Part D, Title I of the CAA. Subpart 1 contains general requirements for SIPs for all nonattainment areas; subpart 2 provides more specific requirements for ozone.) In February 2001, the Supreme Court found EPA's implementation approach unreasonable, concluding that EPA could not ignore subpart 2 when implementing the 8-hour standard. Whitman v. American Trucking Assoc., 121 S.Ct. 903.

The Clear Skies legislation introduced in July 2002 provides for a transitional designation for certain areas that would allow flexibility in implementing the 8-hour ozone NAAQS. This approach is discussed elsewhere in this notice.