Aditional Options Considerecl l,x 

“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 obligationssuch that States may begin SIP 

development upon designation and classificationfor 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 

structurethat can be communicated easily; 4) Provide flexibilityto 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 flexibilityto determine whether to regulate NO,, 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 structuringa proposed implementation rule, EPA has 

tried to stay as close as possible to the principles noted above, particularly with regard to seeking 

flexibleways 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 flexibilitywithin the Supreme Court’s decision. 

EPA has also had the benefit of ideas and recommendations fkom 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 constraintsof 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 

2 
preparing SIPSfor 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 Cbtions 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 0, problem and would produce some 

inequities (e.g., aNarea 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. 

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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 obligationsfor the 8-hour standard. All areas would be classified under subpart 1 for 

the 8-hour standard, although the “textuallyapplicable” 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 designatenonattainment areas under the 8-hour ozone standard. Once an area is 

designated nonattainment under the 8-hour standard, subpart 1provides 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 classificationsfor areas designated nonattainment for the 8-hour 

NAAQS. Under this approach, no areas would be classified subpart 2 for the 8-hour NAAQS. 

Classifv all areas under subpart 2 and place a higher percentage of 8-hour ozone nonattainment 

areas into higher classificationsto reflect the fact that the 8-hour standard is more stringent than 

the 1-hour standard. The commenter did not suggest a mechanism for determiningwhich 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-hourstandard). 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 classifl areas 

based on the difficultyof 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.’ 

‘This commenter also recommended that the category names for the classification scheme 

(in subpart 2) should be reflective of the public health significance of the ozone problem. EPA 

does not believe that the classificationscheme should be the primary way of informing the public 

of the quality of the air in a particular area, and that there are other mechanisms for doing that 

such as the air quality index (AQI) program or the general requirement for public notification 

under section 127 of the CAA. As an illustration, even CAA section 107requires designation as 

nonattainment nearby clean air areas that contributeto another area’s nonattainment. In these 

cases, the nonattainment designation for the contributing part of the area would not be an 

accurate characterization of the quality of the air for public information purposes for that part of 

the nonattainment area, so any classification of that area would also not accurately characterize 

4 
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-how 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 10percent 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. 

the health problem for that part of the nonattainment area. 

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Other methods for translating section 181’sTable 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 solicitingcomment on 

the merits of them. If there is sufficient interest in any of these translations, EPA will consider 

publishing a supplementalproposal on them. 

-Establishing a relationshit, 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 situatiom2 

The other problem with trylng to establish a relationship between monitored 1-hour and 8-hour 

ozone levels for purposes of translating the classificationtable 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 

establishthe translation of table 1 would likely result in a larger number of areas in the higher 

subpart 2 classifications, which would Wher limit an area’s flexibilityin crafting control 

measures appropriate to the area’s problems. 

EPA therefore believes there is no obvious “correct” technicalmethod 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’sTable 1to the 8-hour 

ozone standard. EPA solicits comment, however, on other ways of interpretingCongressional 

intent and on the methods described in this proposal. It should be noted that the translation being 

2Forinstance, a best-fit curve could be established between 1-hour and 8-hour ozone 

levels based on historical air quality data through a variety of means. Even a cursory 

examination of the 1-hour and 8-hour design values for each county, or each hypothetical 

nonattainment area shows a rather large scatter (large standard deviation). In other words, areas 

with the same 1-hourdesign values may have a range of 8-hour design values. Rather than using 

the area’s design values, one could try to establish a relationship between daily maximum 1-hour 

values with daily maximum 8-hour values on a county or monitor basis. Even if these values 

were ranked and paired by ranking (i.e., the highest 1-hourvalue with the highest 8-hour value, 

etc.) the degree of scatter would be less, but would still not reflect how the data actually occur in 

reality. 

6 
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 AQ13levels are designed to trigger immediate 

actions that will keep an area fi-omreaching short-term levels that approach the level considered 

to cause significant harm to the health of person^.^ The levels in the AQI are as follows: 

0 to 50 

51 to 100 

101 to 150 

151 to200 

201 to300 

301 to 500 

Category 

Good 

Moderate 

Unhealthy for Sensitive Groups 

Unhealthy 

Very unhealthy 

Hazardous 

8-hr (or 1-hr) 03 

concentration (ppm) 

up to 0.064 

0.065 up to 0.084 

0.085 up to 0.104 

0.105 up to 0.124 

0.125 up to 0.374 

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 

classifjmg 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? 

3Thecurrent rule on the AQI was published August 4,1999 (64 FR 42530). The rule is 

codifed at 40 CFR 58.50. Additional information on the AQI is found at 

http://~~~.epa.g;ov/airnowlaqibroch/aqi.html#5 . 

440CFR 51.15 1 sets forth the significant harm levels for certain criteria pollutants. The 

level for ozone is 1,200micrograms per cubic meter (ps/m3)or 0.06 ppm, 2-hour average. 

7 
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 emissionsbudget under the 8-hour standard to be adequate. 

EPA’s transportation conformityrules 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 expectationthat the attainment demonstration and/or 

reasonable further progress provision is adequate. This approach would result in revocation of 

the 1-hourstandard 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. Conformitywould 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 hrther 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 conformitywould 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-hourSIP, but also either pass the buildno-build or the nogreater-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 conformityrequirements would likely have to be met 

individuallyfor both standards-for the 8-hour standard in the larger area and for the 1-hour 

standard in the area that comprised the 1-hourozone nonattainment area; this would add 

complexity to the process. 

Because of ths 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 0, 

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-yeargrace 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 0, NAAQS (after 8-hour 0, designation). 

This approach also would create a situation under which conformity would apply to both 

standardsfor areas that remain covered by the 1-hour standard after the first year 

. 

8 
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 0, SIPs (for 8-hour 0, 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’thestage IIrequirement 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 NO, 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 11vapor 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. 

10 
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 timefiames needed. Another reason 

is the fact that there would likely be significant differences fkom 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 (WP) 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 reuuirement be limited to VOC emissions? 

Other options that EPA considered 

5 
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 recommendationwas to allow areas 

to reduce emissions of whatever precursor (ie., 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, 1990would 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 1990base 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 appropriateyear in light of anticipated availability of current informationat the time 

States will be preparing the RFP provisions of their implementationplans. 

How should the RFP resuirements be implemented for areas designated for the 8-hour ozone 

standard that entirelyor 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. 

12 
I) 

Other Issue EPA Considered 

Should EPA use the RFP reauirement to address an upwind State’s responsibility under section 

1lO(a)(Z)(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 

ii-om 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 acheve 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 fi-om 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 11O(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 t 

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. 

w ISSUE: Will EPA be contemplating incentives for areas that want to take early action for 

reducing ozone under the 8-hour standard? 

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f ‘ i *i 

’ 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 thel-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 SIPSfor 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. 

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