The CAA and the TAR provide tribes opportunity and flexibility, but not the obligation to develop a TIP to address the NAAQS. If a tribe elects to develop a TIP, the TAR offers flexibility for the tribe to identify and implement on a case-by-case basis only those CAA programs or reasonably severable program elements needed to address their specific air quality problems. In the TAR, the EPA described this flexible implementation approach as a modular approach. Each tribe may evaluate the particular activities, including potential sources of air pollution within the exterior boundaries of its reservation (or within non-reservation areas for which it has demonstrated jurisdiction), that cause or contribute to its air pollution problem. A tribe may adopt measures for controlling those sources of PM2.5-related emissions, as long as these elements of the TIP are reasonably severable from other CAA requirements. A TIP must include regulations designed to solve specific air quality problems for which the tribe is seeking the EPA's approval, as well as a demonstration that the tribal air agency has the authority from the tribal government to develop and run their program, the capability to enforce their rules, and the resources to implement the program they adopt. In addition, the tribe must receive an eligibility determination from the EPA to be treated in the same manner as a state for the particular matter at issue and to receive authorization from the EPA to run a CAA program.
      The EPA would review and approve, where appropriate, these TIPs as one step of an overall air quality plan to attain the NAAQS. A tribe may step in later to add other elements to the plan, or the EPA may step in to fill gaps in the air quality plan as necessary or appropriate. In approving a TIP, the agency would evaluate whether the plan appropriately coordinates with the overall air quality plan for an area when tribal lands are part of a multi-jurisdictional area.
      Because many PM2.5 nonattainment areas will include multiple jurisdictions, and in some cases both Indian country and state lands, it is particularly important for the tribes and the states to work together to coordinate their planning efforts. States need to incorporate Indian country emissions in their base emissions inventories if Indian country is part of an attainment or nonattainment area. Tribes and states should coordinate their planning activities as appropriate to ensure that neither is adversely affecting attainment of the NAAQS in the area as a whole. Coordinated planning in these areas will help ensure that the planning decisions made by the states and tribes complement each other and that the nonattainment area makes reasonable progress toward attainment and ultimately attains the applicable PM2.5 NAAQS. In reviewing and approving individual TIPs and SIPs, the EPA will determine if together they are consistent with the overall air quality needs of an area.
      To date, very few tribes have submitted for the EPA's approval TIPs covering areas over which they have jurisdiction. In the absence of a TIP, the EPA is authorized under the TAR to implement CAA programs in such areas as necessary or appropriate. For example, an unhealthy air quality situation on an Indian reservation may require the EPA to develop a FIP to reduce emissions from sources on the reservation. Likewise, if the agency determines that sources in an area under tribal jurisdiction could interfere with a larger nonattainment area meeting the NAAQS by its attainment date, it would develop a FIP for those sources in consultation with the tribe as necessary or appropriate.
      States have an obligation to notify other states in advance of any public hearing(s) on their state plans if such plans will significantly impact such other states. 40 CFR 51.102(d)(5). Under section 301(d) of the CAA and the TAR, tribes may become eligible to be treated in a manner similar to states (TAS) for this purpose. Affected tribes with this status must also be informed of the contents of such state plans and given access to the documentation supporting these plans. In addition to this mandated process, the EPA encourages states to extend the same notice to all affected tribes, regardless of their TAS status.
      Executive Orders and the EPA's Indian policies generally call for the EPA to coordinate and consult with tribes on matters that affect tribes. Executive Order 13175, titled, "Consultation and Coordination with Indian Tribal Governments" requires the EPA to develop a process to ensure "meaningful and timely input by tribal officials in the development of regulatory policies that have Tribal implications." In addition, the EPA's policies include the agency's 1984 Indian Policy relating to Indian tribes and implementation of federal environmental programs, the 2014 Office of Air and Radiation's "Handbook for Interacting with Tribal Governments," and the "EPA Policy on Consultation and Coordination with Indian Tribes." Consistent with these policies, the EPA intends to meet with tribes on activities potentially affecting the attainment and maintenance of the current and future PM2.5 NAAQS in Indian country, including agency actions on SIPs. As such, it would be helpful for states to work with tribes with land that is part of the same air quality area during the SIP development process and to coordinate with tribes as they develop their SIPs.

I. Voluntary Programs for Reducing Ambient PM2.5
1. PM Advance Program.
	The EPA believes there are significant advantages for states, tribes and local agencies to take steps to reduce direct PM2.5 emissions and emissions of PM2.5 precursors as early as possible. First and foremost, early reductions help to achieve cleaner air sooner, and help to ensure continued health protection. Second, early steps could help an area avoid a nonattainment designation in the first place, or for an area eventually designated as nonattainment, early reductions could help bring the area back into attainment sooner, which may lead to qualifying for a CDD and subsequent suspension of attainment planning requirements as described in Section IX.C of this preamble. In addition, early action to improve air quality can help an eventual nonattainment area, particularly an area that has never been designated nonattainment before, to establish working relationships between key stakeholders. The EPA's expectation is that early actions to reduce emissions in such areas would be less resource-intensive than actions taken once a nonattainment designation has been made, since at that point the implementation of controls would need to occur in conjunction with actions to comply with other requirements such as nonattainment NSR and transportation conformity.
	In January 2013, the EPA began a new early emissions reduction program for attainment areas called "PM Advance," which is much like the related "Ozone Advance" program that began in April 2012. For additional information and a list of areas that are currently participating in the program, see http://www3.epa.gov/ozonepmadvance.
2. Residential Wood Smoke Programs.
	The EPA recognizes that residential wood smoke is a concern for many nonattainment areas. The EPA estimates that wood stoves, indoor wood furnaces, hydronic heaters and fireplaces emit more than 382,000 tons of PM2.5 into the air throughout the country each year  -  mostly during the winter months. Residential wood smoke can increase fine particle pollution to levels that cause significant health concerns (e.g., asthma attacks, heart attacks, premature death). Wood smoke causes many counties throughout the U.S. to either exceed the national health-based standards for fine particles, or places them on the cusp of exceeding the standards. Because wood stoves, hydronic heaters and other similar appliances can be used around the clock in residential areas, they can cause significant and varying health and quality of life issues.
	To reduce fine particle pollution, many PM2.5 nonattainment areas will need to address residential wood smoke. The EPA has developed the "Strategies for Reducing Residential Wood Smoke" document that provides education and outreach tools, information on regulatory approaches to reduce wood smoke, as well as information about voluntary programs that communities around the country have used. In addition, it includes methods for calculating emissions reductions, funding ideas and the basic components of a wood smoke reduction plan that can be adopted into a SIP as an enforceable control measure. To access the document, go to https://epa.gov/burnwise/burn-wise-strategies-reducing-residential-wood-smoke. For more information on the EPA's wood smoke reduction program, see https://www.epa.gov/burnwise.
J. Improved Stationary Source Emissions Monitoring
1. Summary of Proposal.
	For purposes of demonstrating compliance with the EPA's air quality regulatory requirements, the EPA, states, and sources rely on two basic types of monitoring: ambient air quality monitoring and stationary source emissions monitoring. Ambient air quality monitoring entails collecting and measuring samples of criteria pollutants in ambient air to evaluate air quality as compared to clean air standards and historical information. Stationary source emissions monitoring, on the other hand, entails collecting and using measurement data (or other information) from individual stationary sources to demonstrate compliance with emissions standards, to assess process or control device performance, or to verify work practices. While ambient air quality monitoring is used to assess compliance with the NAAQS, stationary source emissions monitoring is used to assess compliance with source-specific regulations under programs like the New Source Performance Standards (NSPS), the National Emissions Standards for Hazardous Air Pollutants (NESHAP), the compliance assurance monitoring (CAM) program, the title V air operating permits program, and the acid deposition control program, as well as specific SIP control measures.
      Accurate stationary source emissions monitoring is also critical for the purposes of developing accurate emissions inventories and in order to identify appropriate control measures to reduce emissions from stationary sources. In addition, after control measures are in place, stationary source emissions monitoring provides process and control device performance information to the facility operator so that appropriate corrective action can be taken if indicated that emission levels may exceed applicable thresholds. Thus, appropriate stationary source emissions monitoring requirements, like the control measures with which they are associated, are a fundamental element of an approvable SIP.
      Because of the important role that effective stationary source emissions monitoring can play in informing the development of attainment strategies for PM2.5 NAAQS nonattainment areas, the EPA is interested in applied best practices for stationary source emissions monitoring that could be included in guidance for other stationary sources and states. As a result of this interest, the EPA sought to gather information about ways to make the source emissions monitoring data collection process easier and more transparent. In the proposal, the EPA therefore asked for information regarding appropriate examples and supporting data from individual sources and states with experience in this area to inform such future guidance. The EPA sought comment on specific topics and questions regarding source monitoring techniques and asked commenters to submit any examples of improved stationary source emissions monitoring and any other methodologies -- complete with equations and explanations -- for estimating emissions reductions due to improved monitoring.
2. Final Rule.
      The EPA did not propose any specific changes to source monitoring requirements for PM2.5 and is therefore not finalizing any specific requirements, beyond what is required elsewhere in the final rule.
3. Comments and Responses.
      Comment. Several commenters focused on critiquing PM CEMS, PM CPMS and BLDS technology and claim that improved monitoring changes the stringency of existing rules and requires rulemaking. The commenters provided no examples or specific information in response to the request for information.
      Response. We appreciate the information submitted by the commenters, but we are not responding to the comments here because they are not directly pertinent to the rule being finalized. The EPA will continue to explore and implement innovative, cost-effective ideas that offer tangible incentives for improved source monitoring to be adopted as part of the associated emissions limitations that will help achieve additional reductions from stationary sources and bring areas into attainment for the PM2.5 NAAQS in a timely way. See the response to comments document for more detailed information.
K. Stationary Source Test Methods for Emissions of Condensable PM2.5
1. Summary of Proposal.
	As discussed in the proposal, direct PM2.5 is comprised of two components: Filterable PM2.5 and condensable PM2.5 emissions. Accurate test methods for condensable PM2.5 emissions have only been recently developed and approved by the EPA, and in the proposal the EPA explained that use of these test methods, including methods to quantify condensable PM2.5 emissions, were essential for identifying sources of direct PM2.5 emissions which, if better controlled, can help to bring a PM2.5 nonattainment area into attainment. However, the EPA did not propose any changes to those test methods.
	The EPA did propose to require that, where a state needs to adopt new or revised control measures for direct PM2.5 from sources in a nonattainment area, the state must specify PM2.5 emission limits in its SIP that include both filterable and condensable emissions. In addition, compliance testing of those sources must include measurement of condensable emissions (such as through the use of Method 202). The EPA proposed that any new or revised emission limit used as a control measure to bring an area into attainment for any current or future PM2.5 NAAQS must use methods that measure PM2.5 or total PM including both filterable and condensable particulate matter.
      The 2007 PM2.5 Implementation Rule required, beginning on January 1, 2011, that states take into consideration condensable PM2.5 emissions when establishing emission limits for stationary sources as part of any control strategy for PM2.5 NAAQS nonattainment areas.  This date coincided with the effective date of the agency's revisions to test methods for measuring filterable PM10 emissions from stationary sources (Method 201A) and for measuring condensable PM emissions from stationary sources (Method 202).  The revisions to those test methods added procedures to measure PM2.5 filterable and condensable particulate material and increased the precision of Method 202 and improved the consistency in the measurements obtained between source tests performed under different regulatory authorities.
      In the preamble to the 2007 PM2.5 Implementation Rule, the EPA explained that the use of the (then anticipated) revisions to the EPA Method 201A combined with Method 202 to obtain measured source specific emissions of PM2.5 would improve the quality of emissions inventories for stationary sources and would aid in the development of a more reliable attainment strategy, as sources that may have a considerable amount of condensable PM2.5 emissions could be better characterized with the new methods.
2. Final Rule.
      The EPA is finalizing the PM2.5 emissions limit and testing requirement as proposed. For sources that are required to adopt a new or revised direct PM2.5 emissions limit as part of the attainment demonstration (including, but not limited to, for RACT, BACT, or MSM), the state must specify PM2.5 emission limits in its SIP that include both filterable and condensable emissions. In addition, compliance testing requirements for those sources must include both measurement of filterable and condensable emissions. Existing filterable PM emission limitations that are not being revised as part of a Moderate area or Serious area attainment plan can remain expressed in terms of filterable PM and can rely on the existing test method used by the state for compliance determination.
      The EPA continues to believe that using these improved test methods, including methods to quantify condensable PM2.5 emissions, can help identify sources of direct PM2.5 emissions which, if better controlled, can help to bring a PM2.5 nonattainment area into attainment. Likewise, use of these test methods may help a state identify sources whose condensable emissions may have been incorrectly estimated and therefore may not provide meaningful PM2.5 control opportunities.
      Comment. Some commenters stated that the EPA should make clear that as long as testing and monitoring is required for any new filterable and/or condensable PM emission limitation imposed, testing for "total PM2.5" is not required and the EPA should allow states flexibility in determining the best way to demonstrate compliance with any new emission limitations. The new emission limitation could take the form either of a limitation on condensable PM2.5 or a limitation on total direct PM2.5 emissions. The commenter further stated the EPA should make clear that states that specify condensable PM or total PM2.5 emission limitations are not required to adopt Method 202 as the compliance test method.
      Response. In the final rule, the EPA is requiring new or revised PM2.5 emissions limits and associated source testing to account for condensable emissions, but the EPA is not imposing any specific source testing requirements that would require total PM2.5 testing or the use of a specific test method. The EPA acknowledges that states have flexibility to determine the necessary emissions limitations of PM2.5 to meet SIP requirements for the NAAQS attainment. When states assess the contribution of the filterable and condensable PM component to PM2.5 they may require stationary source tests that include both filterable PM2.5 and condensable particulate matter to ensure emission limits are attained by subject facilities. Since we recognize that primary PM2.5 emissions can be measured with the combination of several promulgated test methods depending on the stationary source emission temperature and moisture content, states have the flexibility to require the appropriate filterable and condensable particulate measurement methods based on source conditions.
      Comment: Some commenters agreed with the EPA's proposal not to require consideration of condensable PM in any existing emission limitations that are not otherwise being revised. The commenters stated that no purpose would be served by requiring states to include condensable PM in such standards if no revision is necessary to demonstrate attainment. Other commenters objected to the EPA's proposal to not require states to update all existing PM emission limitations to include limitations on condensable PM. The commenters stated the EPA's proposal is nonsensical and undermines any ability to demonstrate compliance with the Act. The commenters stated that, by the EPA's own admission, inventories that do not reflect measured condensables from direct PM2.5 sources are not an "accurate" inventory of "actual emissions." The commenters further stated that, similarly, areas could not satisfy the criteria for RACM or BACM, or demonstrate expeditious attainment if the existing state emission limitations are not required to be updated to account for condensable emissions from these sources.
      Response. The EPA agrees with the commenters who maintain that existing PM2.5 emissions limits do not need to be revised to include emissions limits for condensable PM for sources from which additional emissions reductions are not needed in order to demonstrate attainment. The EPA does not agree that all existing direct PM2.5 emissions limits in the SIP have to include emissions limits that account for or specifically address condensable PM. However sources with new or revised PM2.5 emissions limits and associated source testing must account for condensable emissions.
      If the state has submitted an attainment demonstration that includes an adequate RACT, BACT, and/or MSM analysis, and has taken into account all known emissions of filterable and condensable PM2.5 in the area, then there is no need to require new condensable PM2.5 emissions limits and testing for sources that were not needed to be additionally controlled for attainment purposes. The state may want to require additional condensable PM2.5 emissions limits and testing to gain a better understanding of the sources in the nonattainment area (especially for sources which may be most likely to emit condensables). This could provide additional information for future SIPs and control programs if nonattainment persists. However, unless specific direct PM2.5 emissions reductions are shown to be needed in order for the area to attain the NAAQS, there does not need to be a SIP requirement to include new condensable emissions limits and testing for all existing sources with PM2.5 emissions limits.
      Additionally, the commenters stated that emissions inventories would not be "accurate" and states could not satisfy their RACM/BACM requirements if condensable emissions were not included in the SIP. Regardless of emissions limits and source testing requirements, quantification and reporting of filterable and condensable PM2.5 emissions is required as part of the emissions inventory and RACT/BACT rule requirements. In some cases, condensable PM2.5 information is available from previous source testing. In other cases, condensable PM2.5 emissions must be estimated through the use of emissions factors that have been developed from source testing of similar sources. States are therefore already required to take into account both filterable and condensable emissions as part of their inventory and control strategy (RACT/BACT) development. See section IV.B. of this preamble for more information on emissions inventory requirements, section IV.D. of this preamble for more information on RACT requirements, and section VI.D. of this preamble for more information on BACT requirements.
X. Revocation of the 1997 Primary Annual PM2.5 NAAQS
A. Summary of the Proposal
      The EPA proposed two options for revoking the 1997 primary annual PM2.5 NAAQS and sought comment on whether to revoke the NAAQS at the current time.
      The two proposed options were:
 Option 1: Revoke the 1997 primary annual PM2.5 NAAQS for all purposes in attainment areas for that NAAQS 1 year after the effective date of the designations for the 2012 primary annual PM2.5 NAAQS; and
 Option 2: Revoke the 1997 primary annual PM2.5 NAAQS for all purposes in all nonattainment and attainment areas for that NAAQS 1 year after the effective date of the designations for the 2012 primary annual PM2.5 NAAQS.
      Under the first proposed option, the EPA would revoke the 1997 primary annual PM2.5 NAAQS for all purposes in areas that are designated as attainment for that NAAQS 1 year after the effective date of designations for the 2012 primary annual PM2.5 NAAQS, as well as in the future as additional areas are redesignated as attainment areas after the initial revocation. The areas addressed by this option are:
 those that were originally designated as attainment areas for the 1997 annual PM2.5 NAAQS; and
 those that were originally designated as nonattainment but have since or will in the future be redesignated to attainment for that NAAQS.
Under this option, the EPA would not revoke the 1997 primary annual PM2.5 NAAQS in any area as long as it is designated nonattainment for that NAAQS. This option is consistent with the approach established for the transition to the current lead and SO2 NAAQS.
      Areas designated nonattainment for the 2012 primary annual PM2.5 NAAQS would be required under Option 1 to comply with applicable CAA requirements as set forth in the CAA. For transportation conformity purposes, these requirements began to apply 1-year after the effective date of designations and include using adequate or approved SIP motor vehicle emissions budgets for the 1997 annual PM2.5 NAAQS or the 2006 24-hour PM2.5 NAAQS where they exist until the area has approved or adequate budgets for the 2012 primary annual PM2.5 NAAQS. Areas that have adequate or approved motor vehicle emissions budgets for both the 1997 annual PM2.5 NAAQS or the 2006 24-hour PM2.5 NAAQS should refer to Question 3.3 in EPA's "Implementing Transportation Conformity Guidance for 2012 PM2.5 Nonattainment Areas" for additional information on which budgets to use in conformity determinations prior to having adequate or approved budgets for the 2012 primary annual PM2.5 NAAQS. The use of such budgets serves as the appropriate anti-backsliding measure for transportation conformity purposes.
      Under the second proposed option, the EPA would revoke the 1997 primary annual PM2.5 NAAQS for all CAA purposes in all nonattainment and attainment areas 1 year after the effective date of designations for the 2012 primary annual PM2.5 NAAQS. The requirements associated with revoking the 1997 primary annual PM2.5 NAAQS in attainment areas for that NAAQS would be the same as those that would apply under Option 1. However, revoking the 1997 primary annual PM2.5 NAAQS in nonattainment areas for that NAAQS would require anti-backsliding measures for areas designated nonattainment for the 1997 annual PM2.5 NAAQS at the time of the revocation. For details on the proposed anti-backsliding measures, refer to the discussion in the proposal for this final rule. (80 FR 15340)
      The EPA also requested comment on not revoking the 1997 primary annual PM2.5 NAAQS at this time. For additional details on all of the proposed options refer to the proposal. (80 FR 15340)
      The EPA did not propose to revoke the 1997 secondary annual PM2.5 NAAQS in this action because that NAAQS has been retained in order to prevent certain welfare effects associated with PM2.5.
      For details on past revocations of the NAAQS including the 1-hour and 1997 ozone NAAQS and prior SO2 and lead NAAQS, refer to the proposal for this final rule. (80 FR 15340)

B. Final Rule
      The EPA is finalizing the revocation of the 1997 primary annual PM2.5 NAAQS for all purposes in attainment areas for that NAAQS as described in Option 1. See 40 CFR 50.13(d). The EPA had proposed that the revocation would be effective 1 year after the effective date of designations for the 2012 primary annual PM2.5 NAAQS. Those designations were effective on April 15, 2015. (80 FR 2206) Therefore, the proposed effective date of the revocation was effectively April 15, 2016. However, this final rule will not be effective before April 15, 2016. Therefore, the EPA is establishing the effective date of this final rule as the effective date of the revocation of the 1997 primary annual PM2.5 NAAQS.
      On the effective date of this final rule, the 1997 primary annual PM2.5 NAAQS will be revoked for all purposes in all attainment areas for that NAAQS, including the areas that were initially designated attainment for the 1997 annual PM2.5 NAAQS. The final rule will have no practical impact on these areas that have always attained the 1997 primary annual PM2.5 NAAQS. These areas have never been required to conduct air quality planning for this NAAQS for any CAA nonattainment purpose, although these areas would continue to implement applicable PSD requirements.
This final rule also revokes the 1997 primary annual PM2.5 NAAQS in areas that have been redesignated to attainment for this NAAQS (i.e., maintenance areas for this NAAQS). These areas will be required to implement their approved maintenance plan for the 1997 primary annual PM2.5 NAAQS and their PSD program. The approved maintenance plan can only be revised if the revision meets the requirements of CAA section 110(l) and, if applicable, CAA section 193,
Similarly, all states will be required to continue to implement applicable control requirements in a FIP or approved SIP designed to address the interstate transport requirements of CAA section 110(a)(2)(D)(i) and (ii) with respect to the 1997 primary annual PM2.5 NAAQS, such as CAIR or CSAPR. These requirements continue to be necessary for downwind nonattainment areas to make progress towards attainment and to assure that the air quality protection achieved in all areas is maintained into the future. These provisions may only be modified if the revision meets the requirements of section 110(l). A similar provision was finalized to preserve interstate transport requirements with respect to the revocation of the 1997 ozone NAAQS. See 40 CFR § 51.1105.
      For areas that remain nonattainment for the 1997 annual PM2.5 NAAQS, the EPA will continue to redesignate areas to attainment as appropriate. For an area that is redesignated to attainment after the effective date of this final rule, the 1997 primary annual PM2.5 NAAQS will be revoked in such an area on the effective date of its redesignation to attainment for that NAAQS. The EPA will not revoke the 1997 primary annual PM2.5 NAAQS in any area as long as it is designated nonattainment for that NAAQS. Until the 1997 primary annual PM2.5 NAAQS is revoked, that NAAQS remains in effect, in parallel with the 2012 primary annual PM2.5 NAAQS, and continues to apply independently and by its own terms.
      After revocation of the 1997 primary annual PM2.5 NAAQS in a given area, the designation for that standard is no longer in effect. The only PM2.5 designations that remain in effect in areas where the 1997 primary annual PM2.5 NAAQS has been revoked are those for the 1997 24-hour PM2.5 NAAQS, the 1997 secondary annual PM2.5 NAAQS, the 2006 24-hour PM2.5 NAAQS and the 2012 primary annual PM2.5 NAAQS. However, the EPA is retaining the listing of the designated areas for the 1997 annual PM2.5 NAAQS in 40 CFR part 81, for the purposes of identifying which areas remain designated as nonattainment for the 1997 annual PM2.5 NAAQS and therefore subject to the requirements of subpart 4 and the areas that have been redesignated to attainment for the 1997 secondary annual PM2.5 NAAQS. Accordingly, such references to historical designations of areas where the 1997 primary annual PM2.5 NAAQS has been revoked should not be viewed as current designations under CAA section 107(d) for the 1997 primary annual PM2.5. As additional areas are redesignated to attainment for the 1997 annual PM2.5 NAAQS, the EPA will indicate in the redesignation rulemaking that the 1997 primary annual NAAQS is revoked on the effective date of the redesignation.
      The EPA notes that areas designated nonattainment for the 1997 annual PM2.5 NAAQS at the time of the final rule's revocation would be required to continue to comply with applicable conformity requirements for that NAAQS. This obligation would continue until the effective date of the redesignation of such an area to attainment for the 1997 annual PM2.5 NAAQS. Transportation and general conformity would apply in all areas that are designated nonattainment for the more health protective 2012 primary annual PM2.5 NAAQS on April 15, 2016, the end of the conformity grace period (CAA section 176 (c)(c)(6) and 40 CFR 93.102(d)). Any areas that are also designated nonattainment or redesignated to attainment for the 1997 24-hour PM2.5 NAAQS or the 2006 24-hour PM2.5 NAAQS are required to continue to make conformity determinations for those NAAQS. See Section IX.B. of this preamble for more information about conformity implementation including information pertaining to conformity requirements for the 1997 secondary annual NAAQS.
      As with other NAAQS revocations, this revocation is framed in the context of the CAA requirements that apply to the NAAQS transitions to ensure that states and nonattainment areas continue to make progress and do not reverse progress, or backslide, from improvements already made in air quality. The CAA contains several provisions indicating Congressional intent not to allow a state to alter or remove provisions from an approved attainment or maintenance plan if the revision would reduce air quality protection. CAA section 193 prohibits modification of a control requirement in effect or required to be adopted as of November 15, 1990 (the date of enactment of the 1990 CAA Amendments), unless such a modification would ensure equivalent or greater emissions reductions. CAA section 172(e), which addresses relaxations of the NAAQS, requires protections for areas that have not attained the NAAQS prior to a relaxation by requiring controls which are at least as stringent as the controls applicable in nonattainment areas prior to any such relaxation. CAA Section 110(l) provides that a SIP revision cannot be approved if it will interfere with attainment or other CAA requirements. Under CAA section 175A(d), an area that is redesignated to attainment may, with an appropriate showing of no interference, cease to implement a measure that is contained in the SIP at the time of redesignation, but only if that measure is retained as a contingency measure in the area's maintenance plan.,
      The EPA has concluded that revoking the 1997 primary annual PM2.5 NAAQS in attainment areas for that NAAQS is consistent with the CAA and precedent in transitioning from a previous NAAQS to a new, more stringent NAAQS. The approach taken in this final rule is consistent with the approach taken in the transition from the past SO2 and lead NAAQS to the current NAAQS for those pollutants. Revoking the 1997 primary annual PM2.5 NAAQS only in attainment areas ensures that any areas that remain designated nonattainment for the 1997 annual PM2.5 NAAQS make progress toward attaining that NAAQS as expeditiously as practicable by implementing the CAA requirements that apply to PM2.5 nonattainment areas as described elsewhere in this final rule.
      Continued attainment of the 1997 primary annual PM2.5 NAAQS in areas that have been redesignated to attainment for that NAAQS will be ensured through the ongoing implementation of the approved maintenance plan that applies in these areas. These areas are required to implement their approved CAA section 175A maintenance plan for the 1997 primary annual PM2.5 NAAQS. They are also required to implement a PSD program for the annual PM2.5 NAAQS, unless they are designated nonattainment for the 2012 primary annual PM2.5 NAAQS where an NNSR program would apply. Revisions to the approved maintenance plan can only be made if the revisions meet the requirements of CAA section 110(l) and, if applicable, CAA section 193.
      Under the selected option for revocation, it is unnecessary to finalize anti-backsliding requirements that would apply to nonattainment areas for the 1997 primary annual PM2.5 NAAQS, because the NAAQS is only being revoked in attainment areas. For former nonattainment areas that have been redesignated to attainment, the EPA has already determined through the redesignation process and approval of maintenance plans that all applicable requirements for the 1997 primary annual PM2.5 NAAQS - including anti-backsliding requirements  -  have been fulfilled. For areas that were initially designated as attainment for both the 1997 annual PM2.5 NAAQS and the 2012 primary annual PM2.5 NAAQS, the approved PSD SIPs satisfy the obligation to submit an approvable maintenance plan for the 2012 primary annual PM2.5 NAAQS under CAA section 110(a)(1).
      The NAAQS is not being revoked in nonattainment areas. Therefore, nonattainment areas will continue to comply with the requirements applicable to their classification for the 1997 annual PM2.5 NAAQS as described in this final rule. For example, areas classified as Serious will be required to implement BACT and BACM level controls and implement an NNSR program that meets the Serious area requirements. Any areas that do not attain by the Serious area deadline would be required to comply with other requirements including most stringent measures and a 5 percent plan. This would ensure that these areas continue to make progress toward attaining the 1997 annual PM2.5 NAAQS and attain that NAAQS as expeditiously as practicable. It would also serve to provide early emissions reductions toward attaining the 2012 primary annual PM2.5 NAAQS. When these areas are eligible for redesignation to attainment, they may submit a redesignation request including a maintenance plan for the 1997 primary annual PM2.5 NAAQS as required by CAA sections 107(d)(3) and 175A. On the effective date of the approval of the redesignation request and maintenance plan, the 1997 primary annual PM2.5 NAAQS would be revoked and the approved maintenance plan along with the implementation of a PSD program for this NAAQS, if they are designated attainment for the 2012 primary annual PM2.5 NAAQS, would ensure continued attainment of the 1997 primary annual PM2.5 NAAQS. Revisions to the approved maintenance plan can only be made if the revisions meet the requirements of CAA section 110(l) and, if applicable, CAA section 193.
      As the EPA proposed, the areas where the NAAQS is being revoked are not required to submit a second 10-year maintenance plan for the 1997 primary annual PM2.5 NAAQS because there is no justification for additional maintenance plan burdens to be imposed on these areas solely because at one time they were designated nonattainment under the revoked 1997 primary annual PM2.5 NAAQS. Not requiring a second 10-year maintenance plan for these areas helps to minimize the burden associated with preparing SIPs for a succession of the NAAQS of increasing stringency. These areas are required to continue to implement their approved maintenance plans for the 1997 primary annual PM2.5 NAAQS. The maintenance plan remains in effect beyond the end of the maintenance period. It may only be revised if the revision complies with the requirements of CAA section 110(l) and, if applicable, CAA section 193. Any areas that are designated nonattainment for the 2012 primary annual PM2.5 NAAQS are required to comply with the applicable CAA requirements as described in this final rule.
      The EPA notes that most of the 39 areas that were initially designated as nonattainment for the 1997 annual PM2.5 NAAQS have already been redesignated to attainment (i.e., they are maintenance areas) and their approved maintenance plans and PSD programs along with the CAA's anti-backsliding provisions in CAA sections 110(l) and 193 ensure continued attainment of the 1997 primary annual PM2.5 NAAQS. If additional areas are redesignated to attainment for the 1997 primary annual PM2.5 NAAQS, their approved maintenance plan and PSD program for the 1997 primary annual PM2.5 NAAQS would prevent backsliding for that NAAQS. As stated previously, applicable conformity requirements would continue to apply for the 1997 annual PM2.5 NAAQS until the effective date of the redesignation of such an area to attainment for the 1997 annual PM2.5 NAAQS.
      In addition, transportation and general conformity will apply in all areas that are designated nonattainment for the more health protective 2012 primary annual PM2.5 NAAQS on April 15, 2016, the end of the conformity grace period (CAA section 176(c)(6) and 40 CFR 93.102(d)). In the DC Circuit Court's December 2006 decision in South Coast v. EPA, as modified following rehearing, the Court held with respect to the anti-backsliding approach for transportation conformity that 1-hour ozone motor vehicle emissions budgets must be used in transportation conformity determinations for the more protective 1997 ozone NAAQS where such SIP motor vehicle emissions budgets have been found adequate or approved, until SIP motor vehicle emissions budgets for the 1997 8-hour ozone NAAQS are available. In addition, the Court affirmed more broadly that in order for transportation conformity determinations to fulfill the requirements of CAA section 176(c)(1), motor vehicle emissions budgets for a prior NAAQS must be used in transportation conformity determinations under a revised NAAQS until emissions budgets for the revised NAAQS are either found adequate or are approved, but that conformity determinations need not be made for a revoked standard. Therefore, areas designated nonattainment for the 2012 primary annual PM2.5 NAAQS that have adequate or approved SIP budgets for the 1997 annual PM2.5 NAAQS must continue to use such budgets in transportation

conformity determinations until budgets for the 2012 primary annual PM2.5 NAAQS are found adequate or are approved.
      With regard to general conformity, the D.C. Circuit Court did not address the need for specific anti-backsliding measures in its initial decision or in the modified decision on the South Coast litigation. However, general conformity determinations will be required in nonattainment areas for the 2012 primary annual NAAQS as required by CAA section 176(c)(5) to ensure that the actions of federal agencies do not cause a violation of that NAAQS, make an existing violation worse or delay timely attainment of the NAAQS or an interim milestone.
      The EPA believes that revoking the 1997 primary annual PM2.5 NAAQS is logical because it results in only one primary annual PM2.5 NAAQS  -  the 2012 primary annual PM2.5 NAAQS  -  applying for purposes of transportation and general conformity in most areas, on the effective date of this rulemaking, which is after the end of the 1-year conformity grace period that applies to newly designated nonattainment areas. (CAA section 176(c)(6)).
      An area that is attaining the more health-protective 2012 primary annual PM2.5 NAAQS would no longer have to expend resources to make conformity determinations or complete other applicable CAA air quality planning requirements for any of the current annual PM2.5 NAAQS after the 1997 primary annual PM2.5 NAAQS is revoked in the area. It should be noted that any areas that are attaining the more health protective 2012 primary annual NAAQS are also necessarily attaining the less stringent 1997 annual PM2.5 NAAQS by a wide margin. See further information for how conformity will be implemented for the 2012 PM2.5 NAAQS in Section IX.B of this preamble.
C. Comments and Responses
1. Comments on Revocation Options 1 and 2 and Not Revoking the 1997 Primary Annual PM2.5 NAAQS.
      Comment: Two commenters supported Option 1 and stated that any areas that are attaining the more protective 2012 PM2.5 NAAQS are also necessarily attaining the less stringent 1997 PM2.5 NAAQS. Some commenters agreed that it is confusing to continue to maintain two NAAQS for the same pollutant. Two commenters stated that revocation of the 1997 NAAQS would relieve the states of the administrative burden of developing and submitting an additional maintenance plan, as well as demonstrating transportation conformity, for areas that are in compliance with the more stringent 2012 PM2.5 NAAQS.
      Response: The EPA is finalizing Option 1, and we agree with the commenter that:
       any area that is attaining the more health protective 2012 primary annual PM2.5 NAAQS of 12.0 μg/m[3] is also attaining the 1997 annual PM2.5 NAAQS of 15.0 μg/m[3];
       revoking the 1997 primary annual NAAQS in areas that have either always been in attainment for that NAAQS or have been redesignated to attainment reduces confusion concerning implementation of the various PM2.5 NAAQS; and
       burden on states is reduced because a second 10-year maintenance plan is not being required for the 1997 primary annual PM2.5 NAAQS.
      If the 1997 primary annual PM2.5 NAAQS were to remain in place after CAA requirements begin to apply for the 2012 primary annual PM2.5 NAAQS, federal agencies, metropolitan planning organizations (MPOs) and other state, local, and federal transportation and air quality agencies in areas that are currently designated nonattainment or maintenance for the 1997 annual PM2.5 NAAQS and are now designated nonattainment for the 2012 primary annual NAAQS would be required to implement CAA requirements for both annual PM2.5 NAAQS concurrently. Additionally, some areas would also be implementing requirements for the 2006 24-hour PM2.5 NAAQS, and two areas remain subject to requirements for the 1997 24-hour PM2.5 NAAQS. This could lead to unnecessary complexity for transportation conformity determinations, especially if an area's boundaries for the various PM2.5 NAAQS differ from one another, as boundaries for several areas do, and the same test of conformity cannot be used for all the PM2.5 NAAQS. Even where an area's boundaries are unchanged, different analysis years under the transportation conformity rule may be required for each PM2.5 NAAQS. It could also lead to general conformity determinations being made in areas that are attainment for the 2012 primary annual PM2.5 NAAQS. Finally, state and local air quality agencies would be required to continue attainment planning activities for the 1997 primary annual PM2.5 NAAQS even if they had air quality data that resulted in their being designated attainment for the 2012 primary annual PM2.5 NAAQS.
      Comment: Some commenters opposed revocation of the 1997 primary annual PM2.5 NAAQS but stated that if the EPA decides to revoke the standard, then Option 1 is preferable since it more fully complies with the health protection functions of the Act. This commenter stated that Option 2 would violate the Act by creating flexibility for regions that have failed to meet the standard. The commenter provides a number of reasons for why Option 2 should not be finalized. The commenter is primarily concerned that revoking the 1997 primary annual NAAQS in areas that are designated nonattainment for that NAAQS at the time of revocation would delay improvements in air quality and allow areas to postpone implementation of controls that apply in PM2.5 areas that are classified as Serious. The commenter also stated that the EPA must identify specific problems to be addressed by revocation and a beneficial purpose for the revocation, and not solely on a claim of the need for flexibility. While the DC Circuit held that the EPA can revoke a NAAQS, the EPA cannot do so to maximize its own discretion.
      Response: The EPA concluded that it is important to have all of the CAA's tools in subpart 4 and, as applicable, subpart 1 available in order to bring areas that are still violating the 1997 annual PM2.5 NAAQS into attainment as expeditiously as practicable. Finalizing Option 1, which revokes the 1997 primary annual PM2.5 NAAQS in attainment areas, including areas redesignated to attainment with an approved CAA section 175A maintenance plan, leaves the CAA's compliance plan for PM areas in place as Congress envisioned it. As described earlier, the EPA is finalizing Option 1 for revoking the 1997 primary annual PM2.5 NAAQS. Under Option 1, the primary annual NAAQS is being revoked in areas that have always been attainment for the 1997 annual PM2.5 NAAQS and in areas that have been redesignated to attainment for that NAAQS. Any area that remains designated nonattainment for the 1997 annual PM2.5 NAAQS on the date of the revocation will have the 1997 primary annual PM2.5 NAAQS revoked after the area attains the 1997 annual PM2.5 NAAQS and is redesignated to attainment consistent with CAA section 107(d)(3)(E) (including the requirement to have an approved CAA section 175A maintenance plan for the primary NAAQS). This means that any area that remains designated nonattainment on the date of the revocation will remain subject to all subpart 4 requirements, including Serious area requirements such as BACT and BACM and more stringent NNSR requirements. If the area does not attain by the Serious area deadline and is not eligible for a 1-year attainment date extension, the area would become subject to the requirement to develop a 5 percent plan. If the area has still not attained, it would be subject to the requirements in CAA section 179(d) for areas that fail to attain.
      The EPA agrees with the commenter's assessment that attaining the 1997 annual PM2.5 NAAQS as expeditiously as practicable has both health and welfare benefits. The final rule ensures that attainment of the 1997 PM2.5 NAAQS is achieved in all areas. Furthermore, the final rule also requires that progress is made toward attainment of the 2012 primary annual PM2.5 NAAQS in nonattainment areas for that NAAQS. In addition, the 1997 annual secondary NAAQS was retained to protect against certain welfare effects. The EPA agrees that if we had revoked the 1997 primary annual PM2.5 NAAQS in areas that are still violating that NAAQS those areas would have started over as Moderate areas for the 2012 NAAQS, rather than being required to move forward with more stringent measures that would have applied to a Serious area for the 1997 annual PM2.5 NAAQS. The revocation of the 1997 primary annual PM2.5 NAAQS as proposed under Option 1 and being finalized is fully consistent with principles of CAA section 172(e). The 1997 primary annual PM2.5 NAAQS is only revoked after an area has attained that NAAQS and been redesignated to attainment with an approved CAA section 175A maintenance plan for that NAAQS. The NAAQS is not being revoked in any area that remains designated nonattainment for the NAAQS and areas that continue to violate the NAAQS continue to be required to implement all of the measures required by subpart 4 (e.g., BACT, BACM and Serious area NNSR) and would be subject to additional subpart 4 requirements (e.g., most stringent measures and a 5 percent plan) if the area cannot or does not attain by the Serious area deadline.
      The EPA is finalizing the revocation of the 1997 primary annual PM2.5 NAAQS only in former nonattainment areas that have been redesignated to attainment. Areas that continue to violate the 1997 annual NAAQS must attain that NAAQS and be redesignated to attainment with an approved CAA section 175A maintenance plan for the 1997 primary annual PM2.5 NAAQS. The nonattainment areas where the NAAQS is not being revoked will be required to comply with all subpart 4 requirements in order to bring them into attainment with the 1997 annual PM2.5 NAAQS as expeditiously as practicable. In sum, the final rule requires CAA subpart 4 to be implemented in all nonattainment areas for the 1997 primary annual PM2.5 NAAQS.
      The EPA also disagrees with the commenter's assertion that the final rule changes CAA subpart 4's requirements. Revocation under Option 1 requires that nonattainment areas attain the 1997 annual PM2.5 NAAQS and be redesignated to attainment before that NAAQS is revoked. Any area that remains nonattainment and continues to violate the 1997 annual NAAQS must first attain that NAAQS by complying with the requirements for subpart 4 and then be redesignated to attainment with an approved maintenance plan for the 1997 primary annual PM2.5 NAAQS as described earlier.
      The EPA has concluded that the final rule fully complies with CAA requirements and is consistent with both past precedents for revoking the original SO2 and lead NAAQS and the tenets of the South Coast decision concerning revocation of the 1-hour ozone NAAQS. (South Coast Air Quality Management Dist. v. EPA, 472 F.3d 882) Areas that continue to violate the 1997 annual NAAQS at the time of the initial revocation are required to attain that NAAQS as expeditiously as practicable through implementation of requirements in subpart 4. This will ensure that these areas continue to make progress toward and eventually attain the 1997 annual NAAQS and make progress toward expeditious attainment of the more health protective 2012 primary annual PM2.5 NAAQS.
      With regard to the comment that the EPA needs a better rationale for the revocation, the EPA is revoking the 1997 primary annual PM2.5 NAAQS in areas that have always been attainment for that NAAQS and in areas that were initially designated nonattainment but have been redesignated to attainment for that NAAQS because this action ensures that only one primary annual PM2.5 NAAQS -- the more protective 2012 primary annual PM2.5 NAAQS--applies in areas that are designated as attainment for the 1997 annual PM2.5 NAAQS. These areas have successfully attained the less stringent 1997 annual PM2.5 NAAQS and have a maintenance plan in place to ensure that they do not slip back into nonattainment for that NAAQS. These areas can only revise their approved maintenance plans if the revision complies with CAA section 110(l) and, if applicable, CAA section 193. Any of these areas that are designated nonattainment for the more health protective 2012 primary annual PM2.5 NAAQS can now focus their efforts on expeditiously attaining the more protective NAAQS as required under subpart 4. Any of these areas that are designated attainment for the more health protective 2012 primary annual PM2.5 NAAQS can focus their resources on other pressing air quality issues.
      The EPA believes that appropriately integrating prior requirements with new goals facilitates coherent, effective and timely planning and controls, and minimizes the separate potentially duplicative submission of requirements left over from previous standards. Expeditious attainment of the 1997 annual PM2.5 NAAQS in nonattainment areas provides both health and welfare benefits that should not be delayed by allowing nonattainment areas to restart the PM2.5 planning process under the Moderate area classification in subpart 4 for areas that are designated nonattainment for the more health protective 2012 primary annual PM2.5 NAAQS. For these reasons and the reasons stated earlier in Section X.a of this preamble, the EPA believes that the revocation of the 1997 primary annual PM2.5 NAAQS in areas that have always been attainment for that NAAQS and in areas that have been redesignated to attainment for that NAAQS provides the appropriate way to move toward attaining the more protective standard in a timely and effective manner. This approach ensures that progress made under previous PM2.5 NAAQS continues in attainment areas and continues in nonattainment areas.
      Comment: Other commenters stated that it causes unnecessary complexity, confusion, and burden to have multiple national standards for the same criteria pollutant. The commenter stated that any concerns about states and nonattainment areas not continuing to make progress or reversing progress can be mitigated through anti-backsliding requirements. On the other hand, two commenters supported the option of not revoking the standard at all. One of these commenters believed that past experience has led to confusion and litigation and has diminished the urgency to attain a new NAAQS.
      Response: As described earlier, the EPA is finalizing revocation Option 1, which leaves the nonattainment designation in place until the area is redesignated to attainment and for those areas to fulfill the requirements of CAA subpart 4 that apply to them. Revoking the 1997 primary annual PM2.5 NAAQS in areas that were designated nonattainment at the time of the revocation could delay attainment of that NAAQS and slow progress on attaining the 2012 primary annual PM2.5 NAAQS because such areas would not be subject to all of the planning requirements in CAA subpart 4 after the date of the revocation. The EPA believes that the final rule simplifies the revocation because the approved maintenance plan and an area's PSD program serve to prevent backsliding. Anti-backsliding measures are not required for nonattainment areas because the NAAQS is not being revoked in nonattainment areas.
      Comment: Several commenters supported Option 2 and stated that it is consistent with implementation rules for the other NAAQS, the 2012 primary annual PM2.5 NAAQS is more stringent and more protective of health than the 1997 primary annual PM2.5 standard, and revocation of the 1997 PM2.5 NAAQS would reduce the burden on states. One of these commenters also stated that, in 1997 PM2.5 NAAQS maintenance areas that have good PM2.5 air quality, revoking the 1997 PM2.5 NAAQS in its entirety will alleviate transportation conformity requirements as well as requirements for the submission of additional maintenance plans.
      Response: As discussed in the proposal, the revocations of the prior lead and SO2 NAAQS were accomplished in a manner consistent with Option 1. (80 FR 15340) The EPA notes that both Options 1 and 2 would reduce burden on the states. Under Option 1, areas that are redesignated to attainment would not be required to submit a second 10-year maintenance plan. However, under Option 1, areas that are designated nonattainment at the time of the revocation would remain subject to the CAA subpart 4 requirements applicable to the area until it attains the NAAQS and is redesignated to attainment through approval of a redesignation request and a CAA section 175A maintenance plan for the primary NAAQS. Under Option 2, areas that remain designated nonattainment at the time of the revocation would be required to implement their approved SIPs for the 1997 annual PM2.5 NAAQS but would not be susceptible to a reclassification from Moderate to Serious, and thus would not be required to adopt additional subpart 4 requirements including requirements for Serious areas that would apply if such an area were reclassified. Not requiring Serious area measures in such an area would delay emissions reductions and improvements in air quality.
      The EPA also notes it retained the 1997 secondary annual NAAQS when the PM2.5 NAAQS was revised in December 2012, thus, full revocation of the 1997 standard would not be appropriate.
      Comment: Two commenters opposed the possible approach of not revoking the 1997 primary annual PM2.5 NAAQS at this time because it would be inconsistent with past actions when a NAAQS has been replaced by the more stringent NAAQS and because it presents an unnecessary burden.
      Response: The EPA is finalizing the proposed revocation of the 1997 primary annual PM2.5 NAAQS for the reasons set forth earlier.
2. Comments on Anti-backsliding Requirements Under Option 1.
      Comment: Some commenters expressed concern that the proposal that an approved CAA section 175A maintenance plan would serve as the anti-backsliding measures may not be consistent with the language of CAA section 172(e).
      Response: The EPA disagrees with the commenter. CAA section 172(e) applies in areas that have not attained the prior NAAQS. In this final rule, the EPA is only revoking the 1997 primary annual PM2.5 NAAQS in areas that have attained that NAAQS and been redesignated to attainment with an approved CAA section 175A maintenance plan. The EPA has determined that implementing the approved maintenance plan along with a PSD program will serve to prevent backsliding in the areas where the NAAQS is being revoked. The approved maintenance plan can only be revised if the revision meets the requirements of CAA section 110(l) and, if applicable, CAA section 193. In order for the 1997 primary annual PM2.5 NAAQS to be revoked in the future in an area that remains designated nonattainment at the time of the initial revocation, such an area would have to attain the NAAQS, submit a redesignation request including a maintenance plan for the primary NAAQS, and the EPA would have to approve that submission. The 1997 primary annual PM2.5 NAAQS would then be revoked in such an area on the effective date of the approval of the redesignation and maintenance plan. That approved maintenance plan would serve to prevent backsliding.
      Comment: Some commenters questioned whether the EPA's conclusion is correct that under Option 1 there is no need for anti-backsliding measures, because the area would have already attained. Commenter stated there may be no need for implementing additional measures, but it seems the state should continue to keep in effect those measures that have brought it to attainment (except NNSR which by statute is replaced by PSD permitting).
      Response: The final rule addresses this comment. Former nonattainment areas where the 1997 primary annual PM2.5 NAAQS is being revoked are required to implement the approved maintenance plan for that NAAQS and to implement a PSD program. The approved maintenance plan remains in effect beyond the end of the maintenance period. The approved maintenance plan can only be revised if the revision complies with CAA section 110(l) and, if applicable, CAA section 193.
XI. Environmental Justice Considerations
      The EPA believes the human health or environmental risk addressed by this action will not have disproportionately high and adverse human health or environmental effects on minority, low-income, or indigenous populations because it would not negatively affect the level of protection provided to human health or the environment under the PM2.5 NAAQS. When promulgated, these regulations will clarify the state implementation plan requirements and the NNSR permitting requirements to be met by states in order to attain the PM2.5 NAAQS as expeditiously as practicable. These requirements are designed to protect all segments of the general population. The EPA included specific discussion in this preamble about actions that could be considered for the protection of minority, low-income or indigenous populations in Section IV.D.6 of this preamble on Moderate area attainment plan control strategies; Section VI.D.7 on Serious area attainment plan control strategies; and Section IX.G of this preamble, measures to ensure appropriate protections for overburdened populations. In addition, as part of the consultation activities conducted in developing this rule, the EPA participated in training and outreach activities with representatives from environmental justice organizations in a March 2014 conference held in Research Triangle Park, NC titled, "Clean Air Act Rulemaking and Permitting Training for EJ Communities." These proposed regulations are designed to protect and enhance the health and safety of these and other populations, and they will not adversely affect the health or safety of minority, low-income or indigenous populations.
XII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review
	This action is a significant regulatory action that was submitted to the Office of Management and Budget (OMB) for review because it raises novel policy issues. Any changes made in response to OMB recommendations have been documented in the docket
B. Paperwork Reduction Act (PRA)
	The information collection activities in this rule have been submitted to the Office of Management and Budget (OMB) under the PRA. The Information Collection Request (ICR) document prepared by the EPA has been assigned the EPA ICR number 2258.03, OMB Control No. 2060-0611. You can find a copy of the ICR in the docket for this rule, and it is briefly summarized here.
	The EPA is finalizing this PM2.5 NAAQS SIP Requirements Rule to describe the CAA requirements that must be met by states with nonattainment areas required to develop attainment plans for attaining and maintaining the NAAQS. The intended effect of the SIP Requirements Rule is to provide certainty to states regarding their planning obligations such that states may begin SIP development. Only states with nonattainment areas are required to submit SIPs under this rule.
	For purposes of analysis of the estimated paperwork burden, the EPA assumed there were 21 existing nonattainment areas for the 1997and 2006 PM2.5 NAAQS., and 14 designated nonattainment areas.  The attainment plan requirements would appear as 40 CFR 51.1000 through 51.1015 which implement CAA subsections 172(c)(1) and (2), and 189(a)(1)(B) and (C), 189(b)(1)(A) and (B) and 189(c). Some states have new nonattainment areas and some states should already have information from emission sources, as facilities should have provided this information to meet 1997 and 2006 PM2.5 NAAQS SIP requirements, operating permits and/or emissions reporting requirements. Such information does not generally reveal the details of production processes. But, to the extent it may, confidential business information for the affected facilities is protected. Specifically, submissions of emissions and control efficiency information that is confidential, proprietary and trade secret and is not emission data are protected from disclosure under the requirements of subsections 503(e) and 114(c) of the CAA.
	The annual state burden for this information collection for the 14 designated 2012 PM2.5 nonattainment areas, averaged over the first 3 years of this ICR, is estimated to be a total of 42,000 labor hours per year at an annual a labor cost of $2.5 million (present value) over the 3 year period, or approximately $420,000 per state for the 6 state respondents. The average annual reporting burden is approximately 2,625 hours per response, with approximately 3 responses per state for 16 state responses. There are no capital or operating and maintenance costs associated with the proposal requirements. Burden is defined at 5 CFR 1320.3(b).
	The annual state burden for this information collection for the 14 existing nonattainment areas for the 1997 and 2006 PM2.5 NAAQS, averaged over the first 3 years of this ICR, is estimated to be a total of 48,600 labor hours per year at an annual labor cost of $$2.9 million (present value) over the 3 year period, or approximately $$417,000 per state for the 7 state respondents. The average annual reporting burden is approximately 3,240 hours per response, with approximately two responses per state for 15 state responses. There are no capital or operating and maintenance costs associated with the proposal requirements. Burden is defined at 5 CFR 1320.3(b).
	An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB control number. The OMB control numbers for the EPA's regulations in 40 CFR are listed in 40 CFR part 9.
C. Regulatory Flexibility Act (RFA)
      I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. In making this determination, the impact of concern is any significant adverse economic impact on small entities. An agency may certify that a rule will not have a significant economic impact on a substantial number of small entities if the rule relieves regulatory burden, has no net burden or otherwise has a positive economic effect on the small entities subject to the rule. This rule will not impose any requirements directly on small entities. Entities potentially affected directly by this final rule include state, local and tribal governments and none of these governments are small governments. Other types of small entities are not directly subject to the requirements of this rule.
D. Unfunded Mandates Reform Act (UMRA)
      This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. This action imposes no enforceable duty on any state, local or tribal governments or the private sector. The CAA imposes the obligation for states to submit attainment plans to implement the PM2.5 NAAQS. In this rule, the EPA is clarifying those requirements. Therefore, this action is not subject to the requirements of sections 202, 203, and 205 of the UMRA.
E. Executive Order 13132: Federalism
      This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government.
F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments
      This final rule does not have tribal implications. It would not have a substantial direct effect on one or more Indian tribes. Furthermore, these regulation revisions do not affect the relationship or distribution of power and responsibilities between the federal government and Indian tribes. The CAA and the TAR establish the relationship of the federal government and tribes in characterizing air quality and developing plans to attain the NAAQS, and these revisions to the regulations do nothing to modify that relationship. Thus, Executive Order 13175 does not apply to this action.
G. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks
      The EPA interprets Executive Order 13045 as applying only to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of "covered regulatory action" in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it implements a previously promulgated health or safety-based federal standard established pursuant to the CAA.
H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use
      This action is not a "significant energy action" as defined in Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not likely to have a significant adverse effect on the supply, distribution, or use of energy.
I. National Technology Transfer and Advancement Act
      This rulemaking does not involve technical standards.
J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations
      The EPA believes the human health or environmental risk addressed by this action will not have disproportionately high and adverse human health or environmental effects on minority, low-income, or indigenous populations. The results of this evaluation are contained in Section XI of this preamble. However, because of the benefits of improved air quality on low SES populations, the EPA conducted outreach to communities on the proposal to encourage comment including a March 2014 environmental justice conference in Research Triangle Park, NC, conference calls and a meeting with the National Environmental Justice Advisory Committee.
K. Congressional Review Act (CRA)
      This action is subject to the CRA, and the EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This action is not a ``major rule'' as defined by 5 U.S.C. 804(2).
L. Determination Under Section 307(d)
	Pursuant to sections 307(d)(1)(E) and 307(d)(1)(V) of the CAA, the Administrator proposes to determine that this action is subject to the provisions of section 307(d). Under section 307(d)(1)(V), the provisions of section 307(d) apply to "such other actions as the Administrator may determine."
M. Judicial Review
      Section 307(b)(1) of the CAA indicates which Federal Courts of Appeal have venue for petitions of review of final agency actions by the EPA under the CAA. This section provides, in part, that petitions for review must be filed in the U.S. Court of Appeals for the District of Columbia Circuit (i) when the agency action consists of ``nationally applicable regulations promulgated, or final actions taken, by the Administrator'' or (ii) when such action is locally or regionally applicable, if ``such action is based on a determination of nationwide scope or effect and if in taking such action the Administrator finds and publishes that such action is based on such a determination.''
      This rule implementing the PM2.5 SIP Requirements is ``nationally applicable'' within the meaning of CAA section 307(b)(1). First, the rulemaking addresses the NAAQS that applies to all states and territories in the U.S. Second, the rulemaking addresses issues relevant to specific existing SIP provisions in states across the U.S. that are located in each of the ten EPA regions, numerous federal circuits and multiple time zones. Third, the rulemaking addresses a common core of knowledge and analysis involved in formulating the decision and a common interpretation of the requirements of the CAA being applied to SIPs in states across the country. Fourth, the rulemaking, by addressing issues relevant to appropriate SIP provisions in one state, may have precedential impacts upon the SIPs of other states nationwide. Courts have found similar rulemaking actions to be of nationwide scope and effect.
      Under section 307(b)(1) of the Act, petitions for judicial review of this action must be filed in the United States Court of Appeals for the District of Columbia Circuit by [INSERT DATE 60 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER]. Any such judicial review is limited to only those objections that are raised with reasonable specificity in timely comments. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality of this rule for the purposes of judicial review nor does it extend the time within which a petition for judicial review may be filed and shall not postpone the effectiveness of such rule or action. Under section 307(b)(2) of the Act, the requirements of this final action may not be challenged later in civil or criminal proceedings brought by us to enforce these requirements.
XIII. Statutory Authority
	The statutory authority for this action is provided by 42 U.S.C. 7403, 7407, 7410, and 7601.
Page 527 of 584 - Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements

List of Subjects
40 CFR part 50
Environmental protection, Air pollution control, Intergovernmental relations, Particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds, ammonia.
40 CFR part 51
Environmental protection, Air pollution control, Intergovernmental relations, Particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds, ammonia.
40 CFR part 93
Environmental protection, Air pollution control, Intergovernmental relations, Particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds, ammonia.

_______________________________________
Dated:

______________________________________
Gina McCarthy,
Administrator.

For the reasons stated in the preamble, Title 40, Chapter I of the Code of Federal Regulations is amended as follows:
PART 50  -  NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS
1. The authority citation for part 50 continues to read as follows:
	Authority: 42 U.S.C. 7401, et. seq.
2. In § 50.13, add paragraph (d) to read as follows:
§ 50.13 National primary and secondary ambient air quality standards for PM2.5.
*   *   *   *   *
(d) Until the effective date of the final Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements rule to be codified at 40 CFR 51.1000 et seq., the 1997 annual PM2.5 NAAQS set forth in this section will continue in effect, notwithstanding the promulgation of the 2012 primary annual PM2.5 NAAQS under § 50.18. The 1997 primary annual PM2.5 NAAQS set forth in this section will no longer apply upon the effective date of the final Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements rule; except that for areas designated nonattainment for the 1997 annual PM2.5 NAAQS set forth in this section as of the effective date of the final Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements rule, the requirements applicable to the 1997 primary annual PM2.5 NAAQS set forth in this section will apply until the effective date of an area's redesignation to attainment for the 1997 annual PM2.5 NAAQS pursuant to the requirements of section 107 of the Clean Air Act. The 1997 secondary annual PM2.5 NAAQS and the 1997 24-hour PM2.5 NAAQS shall remain in effect. The area designations and classifications with respect to the 1997 annual and 24-hour PM2.5 NAAQS remain codified in 40 CFR part 81 in order to provide information on where the 1997 primary annual PM2.5 NAAQS has been revoked and to facilitate the implementation of the 1997 secondary annual PM2.5 NAAQS and the 1997 24-hour PM2.5 NAAQS.
PART 51  -  REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS
3. The authority citation for part 51 continues to read as follows:
	Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.
Subpart I - Review of New Sources and Modifications
4. In §51.165:
a. Revise paragraphs (a)(1)(iv)(A)(1), (a)(1)(x)(A), and (a)(1)(xxxvii)(C)(2);
b. Add paragraph (a)(1)(x)(F);
c. Remove paragraphs (a)(1)(xxxvii)(C)(3), and (4); and
d. Revise paragraphs (a)(2)(i) and (a)(2)(ii)(A).
The revisions and additions read as follows:
§51.165 Permit requirements.
     (a) *   *   *
    (1) *   *   *
    (iv)(A) *   *   *
    (1) Any stationary source of air pollutants that emits, or has the potential to emit, 100 tons per year or more of any regulated NSR pollutant (as defined in paragraph (a)(1)(xxxvii) of this section), except that lower emissions thresholds shall apply in areas subject to subpart 2, subpart 3, or subpart 4 of part D, title I of the Act, according to paragraphs (a)(1)(iv)(A)(1)(i) through (viii) of this section.
    (i) 50 tons per year of volatile organic compounds in any serious ozone nonattainment area.
    (ii) 50 tons per year of volatile organic compounds in an area within an ozone transport region, except for any severe or extreme ozone nonattainment area.
    (iii) 25 tons per year of volatile organic compounds in any severe ozone nonattainment area.
    (iv) 10 tons per year of volatile organic compounds in any extreme ozone nonattainment area.
    (v) 50 tons per year of carbon monoxide in any serious nonattainment area for carbon monoxide, where stationary sources contribute significantly to carbon monoxide levels in the area (as determined under rules issued by the Administrator).
    (vi) 70 tons per year of PM10 in any serious nonattainment area for PM10.
    (vii) 70 tons per year of PM2.5 in any serious nonattainment area for PM2.5.
    (viii) 70 tons per year of any individual precursor for PM2.5 (as defined in paragraph (a)(1)(xxxvii) of this section), in any serious nonattainment area for PM2.5.
*   *   *   *   *
    (x)(A) Significant means, in reference to a net emissions increase or the potential of a source to emit any of the following pollutants, a rate of emissions that would equal or exceed any of the following rates:
                            Pollutant Emission Rate
Carbon monoxide: 100 tons per year (tpy)
Nitrogen oxides: 40 tpy
Sulfur dioxide: 40 tpy
Ozone: 40 tpy of volatile organic compounds or nitrogen oxides
Lead: 0.6 tpy
PM10: 15 tpy
PM2.5: 10 tpy of direct PM2.5 emissions; 40 tpy of sulfur dioxide emissions, 40 tpy of nitrogen oxide emissions, or 40 tpy of VOC emissions, to the extent that any such pollutant is defined as a precursor for PM2.5 in paragraph (a)(1)(xxxvii) of this section.
    *  *  *  *  *
    (F) In any nonattainment area for PM2.5 in which a plan defines ammonia as a regulated NSR pollutant (as a PM2.5 precursor), as defined in paragraph (a)(1)(xxxvii) of this section, the plan shall define "significant" for ammonia for that area, subject to the approval of the Administrator.
    *  *  *  *  *
    (xxxvii) * * *
    (C) * * *
    (2) Sulfur dioxide, nitrogen oxides, volatile organic compounds and ammonia are precursors to PM2.5 in any PM2.5 nonattainment area, unless the State demonstrates to the Administrator's satisfaction or the EPA demonstrates, consistent with section 51.1006(a)(3) of this part, that major stationary sources of a particular precursor do not contribute significantly to PM2.5 levels that exceed the PM2.5 ambient standards in a particular area.
*   *   *   *   *
    (2) Applicability procedures. (i) Each plan shall adopt a preconstruction review program to satisfy the requirements of sections 172(c)(5) and 173 of the Act for any area designated nonattainment for any national ambient air quality standard under subpart C of 40 CFR part 81. Such a program shall apply to any new major stationary source or major modification that is major for the pollutant for which the area is designated nonattainment under section 107(d)(1)(A)(i) of the Act, if the stationary source or modification would locate anywhere in the designated nonattainment area. Different pollutants, including individual precursors, are not summed to determine applicability of a major stationary source or major modification.
    (ii) * * *
    (A) Except as otherwise provided in paragraphs (a)(2)(iii) and (iv) of this section, and consistent with the definition of major modification contained in paragraph (a)(1)(v)(A) of this section, a project is a major modification for a regulated NSR pollutant (as defined in paragraph (a)(1)(xxxvii) of this section), if it causes two types of emissions increases -- a significant emissions increase (as defined in paragraph (a)(1)(xxvii) of this section), and a significant net emissions increase (as defined in paragraphs (a)(1)(vi) and (x) of this section). The project is not a major modification if it does not cause a significant emissions increase. If the project causes a significant emissions increase, then the project is a major modification only if it also results in a significant net emissions increase.
 *   *   *   *   *
5. In Appendix S to part 51:
a. Revise paragraph II.A.4.(i)(a) introductory text;
b. Add paragraphs II.A.4.(i)(a)(7) and (8) and II.A.10.(vi);
c. Revise paragraphs II.A.10.(i) and II.A.31.(ii)(b)(2); and
d. Add paragraphs II.A.31.(ii)(3) and (4).
The revisions and additions read as follows:
Appendix S to Part 51  -  Emission Offset Interpretative Ruling
*   *   *   *   *
    II. * * *
    A. * * *
    4. (i) * * *
    (a) Any stationary source of air pollutants which emits, or has the potential to emit, 100 tons per year or more of a regulated NSR pollutant (as defined in paragraph II.A.31 of this Ruling), except that lower emissions thresholds shall apply in areas subject to subpart 2, subpart 3, or subpart 4 of part D, title I of the Act, according to paragraphs II.A.4(i)(a)(1) through (8) of this ruling.
*   *   *   *   *
    (7) 70 tons per year of PM2.5 in any serious nonattainment area for PM2.5.
    (8) 70 tons per year of any individual PM2.5 precursor (as defined in paragraph II.A.31 of this Ruling) in any Serious nonattainment area for PM2.5.
*   *   *   *   *
    10. (i) Significant means, in reference to a net emissions increase or the potential of a source to emit any of the following pollutants, a rate of emissions that would equal or exceed any of the following rates:
                         Pollutant and Emissions Rate
Carbon monoxide: 100 tons per year (tpy)
Nitrogen oxides: 40 tpy
Sulfur dioxide: 40 tpy
Ozone: 40 tpy of volatile organic compounds or nitrogen oxides
Lead: 0.6 tpy
Particulate matter: 25 tpy of particulate matter emissions
PM10: 15 tpy
PM2.5: 10 tpy of direct PM2.5 emissions; 40 tpy of sulfur dioxide emissions, 40 tpy of nitrogen oxides emissions, or 40 tpy of volatile organic compound emissions, to the extent that any such pollutant is defined as a precursor for PM2.5 in paragraph II.A.31 of this Ruling.
*  *  *  *  *
     (vi) In any nonattainment area for PM2.5 in which a state must regulate ammonia as a regulated NSR pollutant (as a PM2.5 precursor) as defined in paragraph II.A.31 of this Ruling, the state shall define "significant" for ammonia for that area and establish a record to document its supporting basis. All sources with modification projects with increases in ammonia emissions that are not subject to Section IV of this Ruling must maintain records of the non-applicability of Section IV that reference the definition of "significant" for ammonia that is established by the state in the nonattainment area where the source is located.
    31. *   *   *
     (ii) * * *
    (b) * * *
     (2) Sulfur dioxide and nitrogen oxides are regulated as precursors to PM2.5 in all PM2.5 nonattainment areas.
    (3) For any area that was designated nonattainment for PM2.5 on or before April 15, 2015, volatile organic compounds and ammonia shall be regulated as precursors to PM2.5 beginning on April 15, 2017, with respect to any permit issued for PM2.5, unless the following conditions are met: the state submits a SIP for the Administrator's review containing the state's preconstruction review provisions for PM2.5 consistent with section 51.165 of this part and a complete NNSR precursor demonstration consistent with section 51.1006(a)(3) of this part; and such SIP is determined to be complete by the Administrator or deemed to be complete by operation of law in accordance with section 110(k)(1)(B) of the Act by April 15, 2017. If these conditions are met, the precursor(s) addressed by the NNSR precursor demonstration (volatile organic compounds, ammonia, or both) shall not be regulated as a precursor to PM2.5 in such area. If the Administrator subsequently disapproves the state's preconstruction review provisions for PM2.5 and the NNSR precursor demonstration, the precursor(s) addressed by the NNSR precursor demonstration shall be regulated as a precursor to PM2.5 under this Ruling in such area as of April 15 2017, or the effective date of the disapproval, whichever date is later.
    (4) For any area that is designated nonattainment for PM2.5 after April 15, 2015, and was not already designated nonattainment for PM2.5 on or immediately prior to such date, volatile organic compounds and ammonia shall be regulated as precursors to PM2.5 under this Ruling beginning 24 months from the date of designation as nonattainment for PM2.5 with respect to any permit issued for PM2.5, unless the following conditions are met: the state submits a SIP for the Administrator's review which contains the state's preconstruction review provisions for PM2.5 consistent with section 51.165 of this part and a complete NNSR precursor demonstration consistent with section 51.1006(a)(3) of this part; and such SIP is determined to be complete by the Administrator or deemed to be complete by operation of law in accordance with section 110(k)(1)(B) of the Act by the date 24 months from the date of designation. If these conditions are met, the precursor(s) addressed by the NNSR precursor demonstration (volatile organic compounds, ammonia, or both) shall not be regulated as a precursor to PM2.5 in such area. If the Administrator subsequently disapproves the state's preconstruction review provisions for PM2.5 and the NNSR precursor demonstration, the precursor(s) addressed by the NNSR precursor demonstration shall be regulated as a precursor to PM2.5 under this Ruling in such area as of the date 24 months from the date of designation, or the effective date of the disapproval, whichever date is later.
    *   *   *   *   *
6. Revise subpart Z to read as follows:
Subpart Z - Provisions for Implementation of PM2.5 National Ambient Air Quality Standards
Sec.
51.1000	Definitions.
51.1001	Applicability of part 51.
51.1002	Classifications.
51.1003	Attainment plan submissions and due dates.
51.1004	Attainment dates.
51.1005	Attainment date extensions.
51.1006	Requirements for demonstrating insignificant contribution of PM2.5 precursors.
51.1007	[Reserved]
51.1008	Emissions inventory requirements.
51.1009	Moderate area attainment plan control strategy requirements.
51.1010	Serious area attainment plan control strategy requirements.
51.1011	Attainment demonstration and modeling requirements.
51.1012	Reasonable further progress (RFP) requirements.
51.1013	Quantitative milestone requirements.
51.1014	Contingency measures requirements.
51.1015	Clean data requirements.
51.1016	Continued applicability of the FIP and SIP requirements pertaining to interstate transport under CAA section 110(a)(2)(D)(i) and (ii) after revocation of the 1997 primary annual PM2.5 NAAQS.

§ 51.1000	Definitions.
The following definitions apply for purposes of this subpart. Any term not defined herein shall have the meaning as defined in 40 CFR 51.100 or Clean Air Act section 302.
Act means the Clean Air Act as codified at 42 U.S.C. 7401-7671q (2003).
Additional feasible measure is any control measure that otherwise meets the definition of "best available control measure" (BACM) but can only be implemented in whole or in part beginning 4 years after the date of reclassification of an area as Serious and no later than the statutory attainment date for the area.
Additional reasonable measure is any control measure that otherwise meets the definition of "reasonably available control measure" (RACM) but can only be implemented in whole or in part during the period beginning 4 years after the effective date of designation of a nonattainment area and no later than the end of the sixth calendar year following the effective date of designation of the area.
Applicable annual standard is the annual PM2.5 NAAQS established, revised, or retained as a result of a particular PM2.5 NAAQS review.
Applicable attainment date means the latest statutory date by which an area is required to attain a particular PM2.5 NAAQS, unless the EPA has approved an attainment plan for the area to attain such NAAQS, in which case the applicable attainment date is the date approved under such attainment plan. If the EPA grants an extension of an approved attainment date, then the applicable attainment date for the area shall be the extended date.
Applicable 24-hour standard is the 24-hour PM2.5 NAAQS established, revised, or retained as a result of a particular PM2.5 NAAQS review.
Attainment projected inventory means the projected emissions of direct PM2.5 and all PM2.5 precursors from sources included in the base year inventory, and from any additional sources of such emissions expected within the boundaries of the nonattainment area by the projected attainment date for the area.
Average-season-day emissions means the sum of all emissions during the applicable season divided by the number of days in that season.
Base year inventory means the actual emissions of direct PM2.5 and all PM2.5 precursors from all sources within the boundaries of a nonattainment area in one of the 3 years used for purposes of designations or another technically appropriate year.
Best available control measure (BACM) is any technologically and economically feasible control measure that can be implemented in whole or in part within 4 years after the date of reclassification of a PM2.5 nonattainment area and that generally can achieve greater permanent and enforceable emissions reductions in direct PM2.5 emissions and/or emissions of PM2.5 precursors from sources in the area than can be achieved through the implementation of RACM on the same source(s). BACM includes best available control technology (BACT).
Date of designation means the effective date of a PM2.5 area designation as promulgated by the Administrator.
Date of reclassification means the effective date of a PM2.5 area reclassification from Moderate to Serious as promulgated by the Administrator.
Direct PM2.5 emissions means solid particles emitted directly from an air emissions source or activity, or gaseous emissions or liquid droplets from an air emissions source or activity which condense to form particulate matter at ambient temperatures. Direct PM2.5 emissions include filterable and condensable PM2.5 emissions composed of elemental carbon, directly emitted organic carbon, directly emitted sulfate, directly emitted nitrate, and other inorganic particles (including but not limited to crustal material, metals, and sea salt).
Implemented means adopted by the state, fully approved into the SIP by the EPA, and requiring expeditious compliance by affected sources with installation and/or operation of any equipment, control device, process change, or other emission reduction activity.
Major stationary source means any stationary source of air pollutant(s) that emits, or has the potential to emit 100 tons per year or more of direct PM2.5 or any PM2.5 precursor in any Moderate nonattainment area for the PM2.5 NAAQS, or 70 tons per year or more of direct PM2.5 or any PM2.5 precursor in any Serious nonattainment area for the PM2.5 NAAQS.
Mobile source means emissions mobile sources as defined by 40 CFR 51.50.
Most stringent measure (MSM) is any permanent and enforceable control measure that achieves the most stringent emissions reductions in direct PM2.5 emissions and/or emissions of PM2.5 precursors from among those control measures which are either included in the SIP for any other NAAQS, or have been achieved in practice in any state, and that can feasibly be implemented in the relevant PM2.5 NAAQS nonattainment area.
Nonpoint source means emissions nonpoint sources as defined by 40 CFR 51.50.
PM2.5 design value (DV) for a PM2.5 nonattainment area is the highest of the three-year average concentrations calculated for the ambient air quality monitors in the area, in accordance with 40 CFR part 50, appendix N.
PM2.5 NAAQS are the fine particulate matter National Ambient Air Quality Standards codified at 40 CFR part 50.
PM2.5 plan precursors are those PM2.5 precursors required to be regulated in the applicable attainment demonstration or NNSR program.
PM2.5 precursors are sulfur dioxide (SO2), oxides of nitrogen (NOx), volatile organic compounds (VOC), and ammonia (NH3).
Point source means emissions point sources as defined by 40 CFR 51.50.
Precursor demonstration means an optional set of analyses provided by a state that are designed to show that emissions of a particular PM2.5 precursor do not contribute significantly to PM2.5 levels that exceed the relevant PM2.5 standard in a particular nonattainment area. The three types of precursor demonstrations provided in this rule are the comprehensive precursor demonstration, the major stationary source precursor demonstration, and the NNSR precursor demonstration.
Reasonably available control measure (RACM) is any technologically and economically feasible measure that can be implemented in whole or in part within 4 years after the effective date of designation of a PM2.5 nonattainment area and that achieves permanent and enforceable reductions in direct PM2.5 emissions and/or PM2.5 precursor emissions from sources in the area. RACM includes reasonably available control technology (RACT).
Reasonable further progress (RFP) means such annual incremental reductions in emissions of direct PM2.5 and PM2.5 plan precursors as are required for the purpose of ensuring attainment of the applicable PM2.5 NAAQS in a nonattainment area by the applicable attainment date.
RFP projected emissions means the estimated emissions for direct PM2.5 and PM2.5 plan precursors by sector for the years in which quantitative milestones are due for a nonattainment area.
Subpart 1 means subpart 1 of part D of title I of the Act.
Subpart 4 means subpart 4 of part D of title I of the Act.
§ 51.1001	Applicability of part 51.
The provisions in subparts A through X of this part apply to areas for purposes of the PM2.5 NAAQS to the extent they are not inconsistent with the provisions of this subpart.
§ 51.1002	Classifications and Reclassifications.
(a) Initial classification as Moderate PM2.5 nonattainment area. Any area designated nonattainment for a PM2.5 NAAQS shall be classified at the time of such designation, by operation of law, as a Moderate PM2.5 nonattainment area.
(b) Reclassification as Serious PM2.5 nonattainment area. A Moderate nonattainment area shall be reclassified to Serious under the following circumstances:
(1) The EPA shall reclassify as Serious through notice-and-comment rulemaking any Moderate PM2.5 nonattainment area that the EPA determines cannot practicably attain a particular PM2.5 NAAQS by the applicable Moderate area attainment date.
(2) A Moderate PM2.5 nonattainment area shall be reclassified by operation of law as a Serious nonattainment area if the EPA finds through notice-and-comment rulemaking that the area failed to attain a particular PM2.5 NAAQS by the applicable Moderate area attainment date.
§ 51.1003	Attainment plan due dates and submission requirements.
(a) Nonattainment areas initially classified as Moderate.
(1) For any area designated as nonattainment and initially classified as Moderate for a PM2.5 NAAQS, the state(s) shall submit a Moderate area attainment plan that meets all of the following requirements:
(i) Base year emissions inventory requirements set forth at § 51.1008(a)(1);
(ii) Attainment projected emissions inventory requirements set forth at § 51.1008(a)(2);
(iii) Moderate area attainment plan control strategy requirements set forth at § 51.1009;
(iv) Attainment demonstration and modeling requirements set forth at § 51.1011;
(v) Reasonable Further Progress (RFP) requirements set forth at § 51.1012;
(vi) Quantitative milestone requirements set forth at § 51.1013;
(vii) Contingency measure requirements set forth at § 51.1014; and,
(viii) Nonattainment new source review plan requirements pursuant to § 51.165.
(2) The state(s) shall submit its Moderate area attainment plan to the EPA no later than 18 months from the effective date of designation of the area.
(b) Nonattainment areas reclassified to Serious.
(1) For any nonattainment area reclassified to Serious for a PM2.5 NAAQS under § 51.1002(b), in addition to meeting the Moderate area attainment plan submission requirements set forth at § 51.1003(a), the state(s) shall submit a Serious area attainment plan that meets all of the following requirements:
(i) Base year emissions inventory requirements set forth at § 51.1008(b)(1);
(ii) Attainment projected emissions inventory requirements set forth at § 51.1008(b)(2);
(iii) Serious area attainment plan control strategy requirements set forth at § 51.1010;
(iv) Attainment demonstration and modeling requirements set forth at § 51.1011;
(v) Reasonable Further Progress (RFP) requirements set forth at § 51.1012;
(vi) Quantitative milestone requirements set forth at § 51.1013;
(vii) Contingency measure requirements set forth at § 51.1014; and,
(viii) Nonattainment new source review plan requirements pursuant to § 51.165.
(2) The state(s) shall submit its Serious area attainment plan to the EPA according to the following schedule:
(i) Discretionary reclassification. For any nonattainment area reclassified to Serious for a particular PM2.5 NAAQS under § 51.1002(b)(1) because the EPA determined it cannot practicably attain the NAAQS by the applicable Moderate area attainment date, the state(s) shall submit to the EPA no later than 18 months from the effective date of reclassification the portion of the Serious area attainment plan that meets the following requirements:
(A) Base year emissions inventory requirements set forth at § 51.1008(b)(1);
(B) Serious area attainment plan control strategy requirements set forth at § 51.1010(a)(1) thru (4); and
(C) Nonattainment new source review plan requirements pursuant to § 51.165.
The state(s) shall submit to the EPA the portion of the Serious area attainment plan that meets the requirements set forth at paragraphs (b)(1)(ii), and (b)(1)(iv) through (vii) of this section to the EPA by a date that is no later than 4 years after the effective date of reclassification, or two years prior to the attainment date, whichever is earlier.
(ii) Mandatory reclassification. For any nonattainment area reclassified to Serious for a particular PM2.5 NAAQS under § 51.1002(b)(2) because the EPA determined it failed to attain the NAAQS by the applicable Moderate area attainment date, the state(s) shall submit to the EPA a Serious area attainment plan meeting the requirements set forth at paragraphs (b)(1)(i) through (viii) of this section no later than 18 months from the effective date of reclassification.
(iii) If the state(s) submits to the EPA a request for a Serious area attainment date extension simultaneous with the Serious area attainment plan due under paragraph (b)(1) of this section, such a plan shall meet the most stringent measure (MSM) requirements set forth at § 51.1010(b) in addition to the BACM and BACT and additional feasible measure requirements set forth at § 51.1010(a).
(c) Serious nonattainment areas subject to CAA section 189(d) for failing to attain the PM2.5 NAAQS by the applicable Serious area attainment date.
(1) For any Serious nonattainment area that fails to attain the PM2.5 NAAQS by the applicable Serious area attainment date, the state(s) shall submit a revised Serious area attainment plan that demonstrates that each year the area will achieve at least a 5 percent reduction in emissions of direct PM2.5 or a 5 percent reduction in emissions of a PM2.5 plan precursor based on the most recent emissions inventory for the area. The revised attainment plan shall meet the following requirements:
(i) Emissions inventory requirements set forth at § 51.1008(c)(1);
(ii) Emissions inventory requirements set forth at § 51.1008(c)(2);
(iii) Serious area attainment plan control strategy requirements set forth at § 51.1010;
(iv) Attainment demonstration and modeling requirements set forth at § 51.1011;
(v) Reasonable Further Progress (RFP) requirements set forth at § 51.1012;
(vi) Quantitative milestone requirements set forth at § 51.1013; and,
(vii) Contingency measure requirements set forth at § 51.1014.
(2) The state(s) shall submit to the EPA the revised attainment plan meeting the requirements set forth at paragraphs (c)(1)(i) through (vii) of this section no later than 12 months from the applicable Serious area attainment date that was previously missed.
(d) Any attainment plan submitted to the EPA under this section shall establish motor vehicle emissions budgets for the projected attainment year for the area, if applicable. The state shall develop such budgets according to the requirements of the transportation conformity rule as they apply to PM2.5 nonattainment areas (40 CFR part 93).
§ 51.1004	Attainment dates.
(a) The state shall submit a projected attainment date as part of its attainment plan submission under § 51.1003 for any PM2.5 NAAQS nonattainment area located in whole or in part within its boundaries. The state shall justify the projected attainment date for each such nonattainment area (or portion of a nonattainment area) as part of the demonstration of attainment developed and submitted according to the requirements set forth at § 51.1011 and according to the following:
(1) Nonattainment areas initially classified as Moderate.
(i) Except for nonattainment areas that meet the criterion under paragraph (a)(1)(ii) of this section, the projected attainment date for a Moderate PM2.5 nonattainment area shall be as expeditious as practicable with the implementation of all control measures required under § 51.1009 and may be as late as the end of the sixth calendar year after the effective date of designation if the state demonstrates that the implementation of certain control measures that qualify as RACM or RACT or additional reasonable measures, but that are not necessary for demonstrating attainment by the end of the sixth calendar year after the effective date of designation, will not collectively advance the attainment date by at least 1 year.
(ii) The projected attainment date for a Moderate PM2.5 nonattainment area which the state demonstrates cannot practicably attain the applicable PM2.5 NAAQS by the end of the sixth calendar year after the effective date of designation of the area with the implementation of all control measures required under § 51.1009 shall be the end of the sixth calendar year after the effective date of designation unless and until the area is reclassified as Serious according to § 51.1002.
(2) Nonattainment areas reclassified to Serious.
(i) Except for nonattainment areas that meet the criterion under paragraph (a)(2)(ii) of this section, the projected attainment date for a Serious PM2.5 nonattainment area shall be as expeditious as practicable with the implementation of all control measures required under § 51.1010 but no later than the end of the tenth calendar year after the effective date of designation.
 (ii) A state that submits an attainment plan that demonstrates that a Serious PM2.5 nonattainment area cannot practicably attain the PM2.5 NAAQS by the end of the tenth calendar year following the effective date of designation of the area with the implementation of all control measures required under § 51.1010(a) must request an extension of the Serious area attainment date consistent with § 51.1005(b). The request must propose a projected attainment date for the nonattainment area that is as expeditious as practicable, but no later than the end of the fifteenth calendar year following the effective date of designation of the area.
(3) Serious nonattainment areas subject to CAA section 189(d) for failing to attain by the applicable Serious area attainment date. The projected attainment date for a Serious PM2.5 nonattainment area that failed to attain the PM2.5 NAAQS by the applicable Serious area attainment date shall be as expeditious as practicable, but no later than 5 years following the effective date of the EPA's finding that the area failed to attain by the original Serious area attainment date, except that the Administrator may extend the attainment date to the extent the Administrator deems appropriate, for a period no greater than 10 years from the effective date of the EPA's determination that the area failed to attain, considering the severity of nonattainment and the availability and feasibility of pollution control measures.
(b) Except for attainment plans that meet the conditions of paragraphs (a)(1)(ii) or (a)(3) of this section, the Administrator shall approve an attainment date at the same time and in the same manner in which the Administrator approves the attainment plan for the area.
(1) In accordance with paragraph (a)(1)(ii) of this section, if a state demonstrates that a Moderate PM2.5 nonattainment area cannot practicably attain the PM2.5 NAAQS by the end of the sixth calendar year following the effective date of designation of the area, the EPA shall proceed under the provisions of § 51.1002(b)(1) to reclassify the area to Serious through notice-and-comment rulemaking.
§ 51.1005	Attainment date extensions.
(a) Nonattainment areas initially classified as Moderate.
(1) A state with a Moderate PM2.5 nonattainment area may apply for a 1-year attainment date extension for the area if the following conditions are met in the calendar year that includes the applicable attainment date for the area:
(i) The state has complied with all requirements and commitments pertaining to the area in the applicable implementation plan;
(ii) For an area designated nonattainment for a particular 24-hour PM2.5 NAAQS for which the state seeks an attainment date extension, the 98[th] percentile 24-hour concentration at each monitor in the area for the calendar year that includes the applicable attainment date is less than or equal to the level of the applicable 24-hour standard (calculated according to the data analysis requirements in 40 CFR part 50, appendix N);
(iii) For an area designated nonattainment for a particular annual PM2.5 NAAQS for which the state seeks an attainment date extension, the annual average concentration at each monitor in the area for the calendar year that includes the applicable attainment date is less than or equal to the level of the applicable annual standard (calculated according to the data analysis requirements in 40 CFR part 50, appendix N).
(2) The applicable implementation plan for a Moderate PM2.5 nonattainment area for which a state seeks an attainment date extension is the plan submitted to the EPA to meet the requirements of § 51.1003(a).
(3) A Moderate area 1-year attainment date extension runs from January 1 to December 31 of the year following the year that includes the applicable attainment date.
(4) A state with a Moderate area that received an initial 1-year attainment date extension may apply for a second 1-year attainment date extension for the area if the state meets the conditions described in paragraph (a)(1) of this section for the calendar year that includes the applicable attainment date.
(b) Nonattainment areas reclassified as Serious.
(1) A state may apply for one attainment date extension not to exceed 5 years for a Serious nonattainment area if the following conditions are met:
(i) The state demonstrates that attainment of the applicable PM2.5 NAAQS by the approved attainment date for the area would be impracticable or, in the absence of an approved attainment date, attainment of the applicable PM2.5 NAAQS by the applicable statutory attainment date for the area would be impracticable;
(ii) The state has complied with all requirements and commitments pertaining to the area in the applicable implementation plan; and,
(iii) The state demonstrates that the attainment plan for the area includes the most stringent measures (MSM) that are included in the attainment plan of any state or are achieved in practice in any state, and can feasibly be implemented in the area consistent with § 51.1010(b).
(2) At the time of application for an attainment date extension, the state shall submit to the EPA a Serious area attainment plan that meets the following requirements:
(i) Base year and attainment projected emissions inventory requirements set forth at § 51.1008(b);
(ii) Most stringent measures (MSM) requirement described under paragraph (b)(1)(iii) of this section and § 51.1010(b), and best available control measures not previously submitted;
(iii) Attainment demonstration and modeling requirements set forth at § 51.1011 that justify the state's conclusion under paragraph (b)(1)(i) of this section, and that demonstrate attainment as expeditiously as practicable;
(iv) Reasonable Further Progress (RFP) requirements set forth at § 51.1012;
(v) Quantitative milestone requirements set forth at § 51.1013; and,
(vi) Contingency measure requirements set forth at § 51.1014.
(vii) Nonattainment new source review plan requirements pursuant to § 51.165.
(3) The applicable implementation plan for a Serious PM2.5 nonattainment area for which a state seeks an attainment date extension under § 51.1004(a)(2)(ii) is the plan submitted to the EPA to meet the requirements set forth at § 51.1003(a).
(4) The applicable implementation plan for a Serious PM2.5 nonattainment area for which a state seeks an attainment date extension under § 51.1004(a)(2)(i) is the plan submitted to the EPA to meet the requirements set forth at § 51.1003(b)(1).
(5) A state applying for an attainment date extension for a Serious nonattainment area under § 51.1004(a)(2)(ii) shall submit to the EPA a request for an extension at the same time as it submits the Serious area attainment plan due under § 51.1003(b)(1).
(6) A state applying for an attainment date extension for a Serious nonattainment area subsequent to submitting an initial Serious area attainment plan that demonstrated attainment of the NAAQS by the applicable attainment date consistent with § 51.1004(a)(2)(i) at the time of submission may apply for such an extension no later than 60 calendar days prior to the approved attainment date for the area or, in the absence of an approved attainment date, no later than 60 calendar days prior to the applicable statutory attainment date for the area.
(c) Serious nonattainment areas subject to CAA section 189(d) for failing to attain by the applicable Serious area attainment date. If a Serious area fails to attain a particular PM2.5 NAAQS by the applicable Serious area attainment date, the area is then subject to the requirements of section 189(d) of the Act, and, for this reason, the state is prohibited from requesting an extension of the applicable Serious area attainment date for such area.
 (d) For any attainment date extension request submitted pursuant to this section, the requesting state (or states) shall submit a written request and evidence of compliance with these regulations which includes both of the following:
(i) Evidence that all control measures submitted in the applicable attainment plan have been implemented, and
(ii) Evidence that the area has made emission reduction progress that represents reasonable further progress toward timely attainment of the applicable PM2.5 NAAQS.
(e) For a PM2.5 nonattainment area located in two or more states or jurisdictions, all states and/or jurisdictions in which such area is located shall submit separate attainment date extension requests for the area consistent with the requirements set forth at paragraph (d) of this section.
§ 51.1006	Optional PM2.5 precursor demonstrations
(a) A state may elect to submit to the EPA one or more precursor demonstrations for a specific nonattainment area. The analyses conducted in support of any precursor demonstration must be based on precursor emissions attributed to sources and activities in the nonattainment area.
(1) A comprehensive precursor demonstration must show that emissions of a particular precursor from all existing stationary, area, and mobile sources located in the nonattainment area do not contribute significantly to PM2.5 levels that exceed the standard in the area.
(i) Concentration-based contribution analysis. The comprehensive precursor demonstration must evaluate the contribution of a particular precursor to PM2.5 levels in the area. If the contribution of the precursor to PM2.5 levels in the area is not significant, based on the facts and circumstances of the area, then the EPA may deem the demonstration adequate.
(ii) Sensitivity-based contribution analysis. If the contribution of the precursor to PM2.5 levels in the area is significant, based on the facts and circumstances of the area, then the state may submit an analysis evaluating the sensitivity of PM2.5 levels in the area to a decrease in emissions of the precursor in order to determine whether the resulting air quality changes are significant. If the estimated air quality changes determined in the sensitivity analysis are not significant, based on the facts and circumstances of the area, then the EPA may deem the demonstration adequate.
(iii) If a comprehensive precursor demonstration is deemed adequate by the EPA, the state will not be required to evaluate any potential control measures for the relevant precursor for the attainment demonstration.
(2) A major stationary source precursor demonstration must show that emissions of a particular precursor from all existing major stationary sources located in the nonattainment area do not contribute significantly to PM2.5 levels that exceed the standard in the area.
(i) Concentration-based contribution analysis. The major stationary source precursor demonstration must evaluate the contribution of major source emissions of a particular precursor to PM2.5 levels in the area. If the contribution of the precursor to PM2.5 levels in the area is not significant, based on the facts and circumstances of the area, then the EPA may deem the demonstration adequate.
(ii) Sensitivity-based contribution analysis. If the contribution of the precursor to PM2.5 levels in the area is significant, based on the facts and circumstances of the area, then the state may submit an analysis evaluating the sensitivity of PM2.5 levels in the area to a decrease in emissions of the precursor in order to determine whether the resulting air quality changes are significant. If the estimated air quality changes determined in the sensitivity analysis are not significant, based on the facts and circumstances of the area, then the EPA may deem the demonstration adequate.
(iii) If a major stationary source precursor demonstration is deemed adequate by the EPA, the state will not be required to evaluate potential major stationary source control measures for the relevant precursor for the current attainment demonstration.
(3)(i) A NNSR precursor demonstration must evaluate the sensitivity of PM2.5 levels in the nonattainment area to an increase in emissions of a particular precursor in order to determine whether the resulting air quality changes are significant. If the estimated air quality changes determined in the sensitivity analysis are not significant, based on the facts and circumstances of the area, then the EPA may deem the demonstration adequate.
(ii) If a NNSR precursor demonstration for a particular PM2.5 nonattainment area is deemed adequate by the EPA, the state will not be required to control the particular precursor as a regulated NSR pollutant, as defined in section 51.165(a)(1)(xxxvii) of this chapter.
(b) If an area with an adequate precursor demonstration is required to submit another PM2.5 attainment plan because the area was reclassified to Serious, failed to attain by the attainment date, or received a Serious area extension, the previous precursor demonstration does not apply to the new plan. The state must submit an updated precursor demonstration if it seeks to exempt a precursor from control requirements in the new Serious area attainment demonstration or in the NNSR program for the Serious area.
 § 51.1007	[Reserved]
§ 51.1008	Emissions inventory requirements.
(a) For any nonattainment area initially classified as Moderate, the state shall submit to the EPA all of the following:
(1) A base year inventory for the nonattainment area for all emissions sources that meets the following minimum criteria:
(i) The inventory year shall be one of the 3 years for which monitored data were used for designations or another technically appropriate inventory year if justified by the state in the plan submission.
(ii) The inventory shall include actual emissions of all sources within the nonattainment area.
(iii) The emissions values shall be either annual total emissions, average-season-day emissions, or both, as appropriate for the relevant PM2.5 NAAQS. The state shall include as part of the plan a rationale for providing annual or seasonal emissions, and the justification for the period used for any seasonal emissions calculations.
(iv) The inventory shall include direct PM2.5 emissions, separately reported PM2.5 filterable and condensable emissions, and emissions of the scientific PM2.5 precursors.
(v) The state shall report emissions as point sources according to the point source emissions thresholds of the Air Emissions Reporting Requirements (AERR), 40 CFR part 51, subpart A.
(vi) The detail of the emissions inventory shall be consistent with the detail and data elements required by 40 CFR part 51, subpart A.
(2) An attainment projected inventory for the nonattainment area that meets the following minimum criteria:
(i) The year of the projected inventory shall be the most expeditious year for which projected emissions show modeled PM2.5 concentrations below the level of the NAAQS.
(ii) The emissions values shall be projected emissions of the same sources included in the base year inventory for the nonattainment area (i.e., those only within the nonattainment area) and any new sources. The state shall include in this inventory projected emissions growth and contraction from both controls and other causes during the relevant period.
(iii) The temporal period of emissions shall be the same temporal period (annual, average-season-day, or both) as the base year inventory for the nonattainment area.
(iv) Consistent with the base year inventory for the nonattainment area, the inventory shall include direct PM2.5 emissions, separately reported PM2.5 filterable and condensable emissions, and emissions of the scientific PM2.5 precursors.
(v) The same sources reported as point sources in the base year inventory for the nonattainment area shall be provided as point sources in the attainment projected inventory for the nonattainment area. Stationary nonpoint and mobile source projected emissions shall be provided using the same detail (e.g., state, county, and process codes) as the base year inventory.
(vi) The same detail of the emissions included shall be consistent with the level of detail and data elements as in the base year inventory (i.e., as required by 40 CFR part 41, subpart A).
(b) For any nonattainment area reclassified as Serious, the state shall submit to the EPA all of the following:
(1) For purposes of meeting the emissions inventory requirements of CAA section 172(c)(3), a base year inventory for the nonattainment area for all emissions sources that meets the requirements listed under paragraph (a)(1) (ii) through (a)(1)(vi) of this section. In addition, the inventory shall use the Serious area definition of a major source listed under § 51.165(a)(1)(iv)(A)(vii) and (viii) and consistent with Table 1 of 40 CFR Appendix A to subpart A of 40 CFR part 51 in determining sources to include as point sources. Finally, the inventory year shall be one of the 3 years for which monitored data were used for reclassification to Serious, or another technically appropriate inventory year if justified by the state in the plan submission.
(2) An attainment projected inventory for the nonattainment area that meets the criteria listed under paragraph (a)(2) of this section.
(c) Serious nonattainment areas subject to CAA section 189(d) for failing to attain a PM2.5 NAAQS by the applicable Serious area attainment date. No later than 12 months after the EPA finds through notice-and-comment rulemaking that a Serious nonattainment area, or portion thereof contained within a state's borders, fails to attain a PM2.5 NAAQS by the applicable attainment date and thus becomes subject to the requirements under CAA section 189(d), the state shall submit to the EPA all of the following:
(1) For purposes of meeting the emissions inventory requirements of CAA section 172(c)(3), a base year inventory for the nonattainment area for all emissions sources that meets the requirements listed under paragraph (a)(1) (ii) through (a)(1)(vi) of this section. In addition, the inventory shall use the Serious area definition of a major source listed under § 51.165(a)(1)(iv)(A)(vii) and (viii) and consistent with Table 1 of 40 CFR Appendix A to subpart A of 40 CFR part 51 in determining sources to include as point sources. The inventory year shall be one of the 3 years for which monitored data were used to determine that the area failed to attain the PM2.5 NAAQS by the applicable Serious area attainment date, or another technically appropriate inventory year if justified by the state in the plan submission.
(2) An attainment projected inventory for the nonattainment area as defined by § 51.1000(e) and that meets the criteria listed under paragraph (a)(2) of this section.
§ 51.1009	Moderate area attainment plan control strategy requirements.
(a) The state shall identify, adopt, and implement control measures, including control technologies, on sources of direct PM2.5 emissions and sources of emissions of PM2.5 precursors located in any Moderate PM2.5 nonattainment area or portion thereof located within the state consistent with the following:
(1) The state shall identify all sources of direct PM2.5 emissions and all sources of emissions of PM2.5 precursors in the nonattainment area in accordance with the emissions inventory requirements of § 51.1008(a);
(2) The state shall identify all potential control measures to reduce emissions from all sources of direct PM2.5 emissions and all sources of emissions of PM2.5 precursors in the nonattainment area identified under paragraph (a)(1) of this section.
(i) The state may elect not to identify potential control measures to reduce emissions from any sources if it has submitted a comprehensive precursor demonstration deemed adequate by the EPA pursuant to section 51.1006.
(ii) The state may elect not to identify potential control measures to reduce emissions from any major stationary sources of a particular PM2.5 precursor if it has submitted a major stationary source precursor demonstration deemed adequate by the EPA pursuant to section 51.1006.
 (3) For any potential control measure identified under paragraph (a)(2) of this section, the state may make a demonstration that such measure is not technologically or economically feasible to implement in whole or in part by the end of the sixth calendar year following the effective date of designation of the area, and the state may eliminate such whole or partial measure from further consideration under this paragraph.
(i) For purposes of evaluating the technological feasibility of a potential control measure, the state may consider factors including but not limited to a source's processes and operating procedures, raw materials, physical plant layout, and potential environmental impacts such as increased water pollution, waste disposal, and energy requirements.
(ii) For purposes of evaluating the economic feasibility of a potential control measure, the state may consider factors including but not limited to capital costs, operating and maintenance costs, and cost effectiveness of the measure.
(iii) The state must submit to the EPA as part of its Moderate area attainment plan a detailed written justification for eliminating from further consideration any potential control measure identified under paragraph (a)(2) of this section on the basis of technological or economic infeasibility.
(4) The state shall use air quality modeling that meets the requirements of § 51.1011(a) and that accounts for emissions reductions estimated due to all technologically and economically feasible control measures identified for sources of direct PM2.5 emissions and sources of emissions of PM2.5 precursors in the Moderate PM2.5 nonattainment area to demonstrate that the area can attain the applicable PM2.5 NAAQS as expeditiously as practicable but no later than the end of the sixth year following the effective date of designation of the area. The state may use air quality modeling to demonstrate that the Moderate PM2.5 nonattainment area cannot practicably attain the applicable PM2.5 NAAQS by such date.