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 for the nonattainment area means the projected emissions of direct PM2.5 and all PM2.5 precursors on the projected attainment date for the area. This projected inventory includes sources included in the base year inventory for the nonattainment area revised to account for changes in direct PM2.5 and all PM2.5 precursors through implementation of the plan and 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 for the nonattainment area 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 Moderate PM2.5 nonattainment area to Serious and that generally can achieve greater permanent and enforceable emissions reductions in direct PM2.5 emissions and/or emissions of PM2.5 plan 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 or liquid particles emitted directly from an air emissions source or activity, or reaction products of gases emitted directly from an air emissions source or activity which form particulate matter as they reach 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 organic or inorganic particles that exist or form through reactions as emissions reach ambient temperatures (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 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 plan 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 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 3-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 plan and/or NNSR program.

PM2.5 precursors are Sulfur dioxide (SO2), Oxides of nitrogen (NOX), Volatile organic compounds (VOC), and Ammonia (NH3).

Point source means 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.

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.

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 plan precursor emissions from sources in the area. RACM includes reasonably available control technology (RACT).

RFP projected emissions means the estimated emissions for direct PM2.5 and PM2.5 plan precursors by source category or subcategory 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.

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.

(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.

(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. (A) 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:

(1) Base year emissions inventory requirements set forth at § 51.1008(b)(1);

(2) Serious area attainment plan control strategy requirements set forth at § 51.1010(a)(1) through (4); and,

(3) Nonattainment new source review plan requirements pursuant to § 51.165.

(B) 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 2 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 within 18 months from the effective date of reclassification, or 2 years before the attainment date, whichever is earlier.

(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;

(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 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).

(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 through the implementation of all control measures required under § 51.1009. The attainment date 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 the control measures that qualify as RACM, RACT, and 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.

(2) [Reserved]

(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 98th 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 first 1-year extension year.

(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;

(vi) Contingency measure requirements set forth at § 51.1014; and,

(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:

(1) Evidence that all control measures submitted in the applicable attainment plan have been implemented, and

(2) 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.

(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. If the state chooses to conduct a comprehensive precursor demonstration, the state must conduct the analysis in paragraph (a)(1)(i) of this section and it may conduct the analysis in paragraph (a)(1)(ii) of this section.

(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 approve the demonstration.

(ii) Sensitivity-based contribution analysis. If the concentration-based contribution analysis does not support a finding of insignificant contribution, based on the facts and circumstances of the area, then the state may choose to 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 approve the demonstration.

(iii) If a comprehensive precursor demonstration is approved by the EPA, the state will not be required to control emissions of the relevant precursor from existing sources in the current attainment plan.

(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. If the state chooses to conduct a major stationary source precursor demonstration, the state must conduct the analysis in paragraph (a)(2)(i) of this section and it may conduct the analysis in paragraph (a)(2)(ii) of this section.

(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 approve the demonstration.

(ii) Sensitivity-based contribution analysis. If the concentration-based contribution analysis does not support a finding of insignificant contribution, based on the facts and circumstances of the area, then the state may choose to 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 approve the demonstration.

(iii) If a major stationary source precursor demonstration is approved by the EPA, the state will not be required to control emissions of the relevant precursor from existing major stationary sources in the current attainment plan.

(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, the state may use that information to identify new major stationary sources and major modifications of a precursor that will not be considered to contribute significantly to PM2.5 levels that exceed the standard in the nonattainment area.

(ii) If a NNSR precursor demonstration for a particular PM2.5 nonattainment area is approved, the state may exempt such new major stationary sources or major modifications of the particular precursor from the requirements for PM2.5 in § 51.165.

(b) If an area with one or more precursor demonstrations approved by the EPA is required to submit another PM2.5 attainment plan in accordance with § 51.1003 of this part, the current precursor demonstration(s) will not apply to the new plan. The state must submit the appropriate updated precursor demonstration(s) if it seeks to exempt sources of a particular precursor from control requirements in the new Serious area attainment demonstration or in the NNSR program for the Serious area.

(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, including precursors that are not PM2.5 plan precursors pursuant to a precursor demonstration under § 51.1006.

(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, including precursors that are not PM2.5 plan precursors pursuant to a precursor demonstration under § 51.1006 of this part.

(v) The same sources reported as point sources in the base year inventory for the nonattainment area shall be included 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 for the nonattainment area.

(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 for the nonattainment area (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 paragraphs (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), and(a)(1)(vii) and (viii), and consistent with Table 1 of Appendix A to subpart A of this part 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 paragraphs (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 Appendix A to subpart A of this part 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.

(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 plan 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 plan precursors in the nonattainment area identified under paragraph (a)(1) of this section.

(i) The state is not required to identify and evaluate potential control measures to reduce emissions of a particular PM2.5 precursor from any existing sources if the state has submitted a comprehensive precursor demonstration approved by the EPA pursuant to § 51.1006, except where the EPA requires such information as necessary to evaluate the comprehensive precursor demonstration pursuant to § 51.1006(a)(1)(ii).

(ii) The state is not required to identify and evaluate potential control measures to reduce emissions of a particular PM2.5 precursor from any existing major stationary sources if the state has submitted a major stationary source precursor demonstration approved by the EPA pursuant to § 51.1006, except where the EPA requires such information as necessary to evaluate the major stationary source precursor demonstration pursuant to § 51.1006(a)(1)(ii).

(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 plan 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.

(i) If the state demonstrates through air quality modeling that the area can attain the applicable PM2.5 NAAQS by the end of the sixth calendar year following the effective date of designation of the area, the state shall adopt and implement all technologically and economically feasible control measures identified under paragraph (a)(3) of this section that are necessary to bring the area into attainment by such date. The state shall also adopt and implement all other technologically and economically feasible measures identified under paragraph (a)(3) of this section that, when considered collectively, would advance the attainment date for the area by at least 1 year. If the state demonstrates through this analysis that control measures for reducing emissions of a PM2.5 precursor would not be necessary for attainment as expeditiously as practicable or to advance the attainment date, then the state would not be required to include control measures for the precursor in the Moderate area attainment plan, nor be required to address the precursor in the RFP plan, quantitative milestones and associated reports, and contingency measures.

(A) Any control measure identified for adoption and implementation under this paragraph that can be implemented in whole or in part by 4 years after the effective date of designation of the Moderate PM2.5 nonattainment area shall be considered RACM for the area. Any such control measure that is also a control technology shall be considered RACT for the area.

(B) Any control measure identified for adoption and implementation under this paragraph that can only be implemented in whole or in part during the period beginning 4 years after the effective date of designation of the Moderate PM2.5 nonattainment area and the applicable attainment date for the area shall be considered an additional reasonable measure for the area.

(ii) If the state demonstrates that the area cannot practicably attain the applicable PM2.5 NAAQS by the end of the sixth calendar year following the effective date of designation of the area, the state shall adopt all technologically and economically feasible control measures identified under paragraph (a)(3) of this section. This requirement also applies to areas that demonstrate pursuant to section 179B that the plan would be adequate to attain or maintain the standard but for emissions emanating from outside the United States.

(A) Any control measure identified for adoption and implementation under this paragraph that can be implemented in whole or in part by 4 years after the effective date of designation of the Moderate PM2.5 nonattainment area shall be considered RACM for the area. Any such control measure that is also a control technology shall be considered RACT for the area.

(B) Any control measure identified for adoption and implementation under this paragraph that can only be implemented in whole or in part during the period beginning 4 years after the effective date of designation of the Moderate PM2.5 nonattainment area through the end of the sixth calendar year following the effective date of designation of the area shall be considered an additional reasonable measure for the area.

(b) The state shall adopt control measures, including control technologies, on sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors located within the state but outside the Moderate PM2.5 nonattainment area if adopting such control measures is necessary to provide for attainment of the applicable PM2.5 NAAQS in such area.

(c) For new or revised source emissions limitations on sources of direct PM2.5 emissions, the state shall establish such emission limitations to apply either to the total of the filterable plus condensable fractions of direct PM2.5, or to filterable PM2.5 and condensable PM2.5 separately.

(a) The state shall identify, adopt, and implement best available control measures, including control technologies, on sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors located in any Serious PM2.5 nonattainment area or portion thereof located within the state and 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(b).

(2) The state shall identify all potential control measures to reduce emissions from all sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors in the nonattainment area identified under paragraph (a)(1) of this section.

(i) The state shall survey other NAAQS nonattainment areas in the U.S. and identify any measures for direct PM2.5 and PM2.5 plan precursors not previously identified by the state during the development of the Moderate area attainment plan for the area.

(ii) The state is not required to identify and evaluate potential control measures to reduce emissions of a particular PM2.5 precursor from any existing sources if the state has submitted a comprehensive precursor demonstration approved by the EPA, except where the EPA requires such information as necessary to evaluate the comprehensive precursor demonstration pursuant to § 51.1006(a)(1)(ii).

(iii) The state is not required to identify and evaluate potential control measures to reduce emissions of a particular PM2.5 precursor from any existing major stationary sources if the state has submitted a major stationary source precursor demonstration approved by the EPA, except where the EPA requires such information as necessary to evaluate the major stationary source demonstration pursuant to § 51.1006(a)(1)(ii).

(3) The state may make a demonstration that any measure identified under paragraph (a)(2) of this section is not technologically or economically feasible to implement in whole or in part by the end of the tenth calendar year following the effective date of designation of the area, and 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 capital costs, operating and maintenance costs, and cost effectiveness of the measure.

(iii) The state shall submit to the EPA as part of its Serious area attainment plan submission 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. The state shall provide as part of its written justification an explanation of how its criteria for determining the technological and economic feasibility of potential control measures under paragraphs (a)(3)(i) and (ii) of this section are more stringent than its criteria for determining the technological and economic feasibility of potential control measures under § 51.1009(a)(3)(i) and (ii) for the same sources in the PM2.5 nonattainment area.

(4) Except as provided under paragraph (a)(3) of this section, the state shall adopt and implement all potential control measures identified under paragraph (a)(2) of this section.

(i) Any control measure that can be implemented in whole or in part by the end of the fourth year following the date of reclassification of the area to Serious shall be considered a best available control measure for the area. Any such control measure that is also a control technology for a stationary source in the area shall be considered a best available control technology for the area.

(ii) Any control measure that can be implemented in whole or in part between the end of the fourth year following the date of reclassification of the area to Serious and the applicable attainment date for the area shall be considered an additional feasible measure.

(5) The state shall use air quality modeling that meets the requirements of § 51.1011(b) and that accounts for emissions reductions estimated due to all best available control measures, including best available control technologies, and additional feasible measures identified for sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors in the area to demonstrate that the area can attain the PM2.5 NAAQS as expeditiously as practicable but no later than the end of the tenth calendar year following the effective date of designation of the area, or to demonstrate that the Serious PM2.5 nonattainment area cannot practicably attain the applicable PM2.5 NAAQS by such date.

(b) For a Serious PM2.5 nonattainment area for which air quality modeling demonstrates the area cannot practicably attain the applicable PM2.5 NAAQS by the end of the tenth calendar year following the date of designation of the area, the state shall identify, adopt, and implement the most stringent control measures that are included in the attainment plan for any state or are achieved in practice in any state, and can be feasibly implemented in the area, consistent with the following requirements.

(1) The state shall identify all sources of direct PM2.5 emissions and sources of emissions of PM2.5 precursors in the nonattainment area in accordance with the emissions inventory requirements of § 51.1008(b).

(2) The state shall identify all potential control measures to reduce emissions from all sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors in the nonattainment area identified under paragraph (b)(1) of this section.

(i) For the sources and source categories represented in the emission inventory for the nonattainment area, the state shall identify the most stringent measures for reducing direct PM2.5 and PM2.5 plan precursors adopted into any SIP or used in practice to control emissions in any state.

(ii) The state shall reconsider and reassess any measures previously rejected by the state during the development of any previous Moderate area or Serious area attainment plan control strategy for the area.

(3) The state may make a demonstration that a measure identified under paragraph (b)(2) of this section is not technologically or economically feasible to implement in whole or in part by 5 years after the applicable attainment date for the area, and 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 capital costs, operating and maintenance costs, and cost effectiveness of the measure.

(iii) The state shall submit to the EPA as part of its Serious area attainment plan submission a detailed written justification for eliminating from further consideration any potential control measure identified under paragraph (b)(2) of this section on the basis of technological or economic infeasibility.

(4) Except as provided under paragraph (b)(3) of this section, the state shall adopt and implement all control measures identified under paragraph (b)(2) of this section that collectively shall achieve attainment as expeditiously as practicable but no later than 5 years after the applicable attainment date for the area.

(5) The state shall use air quality modeling that meets the requirements of § 51.1011(b) and that accounts for emissions reductions estimated due to all most stringent measures; best available control measures, including best available control technologies; and additional feasible measures identified for sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors in the area to demonstrate that the area can attain the PM2.5 NAAQS as expeditiously as practicable but no later than the end of the fifteenth calendar year following the effective date of designation of the area.

(c) For a Serious PM2.5 nonattainment area that the EPA has determined has failed to attain by the applicable attainment date, the state shall submit a revised attainment plan with a control strategy 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; and that the area will attain the standard as expeditiously as practicable consistent with § 51.1004(a)(3). The plan shall meet the requirements of § 51.1003(c)-(d), and the following requirements:

(1) The state shall identify all sources of direct PM2.5 emissions and sources of emissions of PM2.5 precursors in the nonattainment area in accordance with the emissions inventory requirements of § 51.1008(b).

(2) The state shall identify all potential control measures to reduce emissions from all sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors in the nonattainment area identified under paragraph (c)(1) of this section.

(i) For the sources and source categories represented in the emission inventory for the nonattainment area, the state shall identify the most stringent measures for reducing direct PM2.5 and PM2.5 plan precursors adopted into any SIP or used in practice to control emissions in any state, as applicable.

(ii) The state shall reconsider and reassess any measures previously rejected by the state during the development of any Moderate area or Serious area attainment plan control strategy for the area.

(3) The state may make a demonstration that a measure identified under paragraph (c)(2) of this section is not technologically or economically feasible to implement in whole or in part within 5 years or such longer period as the EPA may determine is appropriate after the EPA's determination that the area failed to attain by the Serious area attainment date, and 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 capital costs, operating and maintenance costs, and cost effectiveness of the measure.

(iii) The state shall submit to the EPA as part of its Serious area attainment plan submission a detailed written justification for eliminating from further consideration any potential control measure identified under paragraph (c)(2) of this section on the basis of technological or economic infeasibility.

(4) Except as provided under paragraph (c)(3) of this section, the state shall adopt and implement all control measures identified under paragraph (c)(2) of this section that collectively achieve attainment of the standard as expeditiously as practicable pursuant to § 51.1004(a)(3).

(5) The state shall conduct air quality modeling that meets the requirements of § 51.1011(b) and that accounts for emissions reductions due to control measures needed to meet the annual reduction requirement of 5 percent of direct PM2.5 or a PM2.5 plan precursor; most stringent measures; best available control measures, including best available control technologies; and additional feasible measures identified for sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors in the area in order to demonstrate that the area can attain the PM2.5 NAAQS as expeditiously as practicable.

(d) The state shall adopt control measures, including control technologies, on sources of direct PM2.5 emissions and sources of emissions of PM2.5 plan precursors located within the state but outside the Serious PM2.5 nonattainment area if adopting such control measures is necessary to provide for attainment of the applicable PM2.5 NAAQS in such area by the attainment date.

(e) For new or revised source emissions limitations on sources of direct PM2.5 emissions, the state shall establish such emission limitations to apply either to the total of the filterable plus condensable fractions of direct PM2.5, or to filterable PM2.5 and condensable PM2.5 separately.

(a) Nonattainment areas initially classified as Moderate. The attainment demonstration due to the EPA as part of any Moderate area attainment plan required under § 51.1003(a) shall meet all of the following criteria:

(1) The attainment demonstration shall show the projected attainment date for the Moderate nonattainment area that is as expeditious as practicable in accordance with the requirements of § 51.1004(a)(1).

(2) The attainment demonstration shall meet the requirements of Appendix W of this part and shall include inventory data, modeling results, and emission reduction analyses on which the state has based its projected attainment date.

(3) The base year for the emissions inventory required for an attainment demonstration under this paragraph shall be one of the 3 years used for designations or another technically appropriate inventory year if justified by the state in the plan submission.

(4) The control strategies modeled as part of the attainment demonstration shall be consistent with the following as applicable:

(i) For a Moderate area that can demonstrate attainment of the applicable PM2.5 NAAQS no later than the end of the sixth calendar year following the date of designation of the area with the implementation of RACM and RACT and additional reasonable measures, the control strategies modeled as part of the attainment demonstration shall be consistent with control strategy requirements under § 51.1009(a).

(ii) For a Moderate area that cannot practicably attain the applicable PM2.5 NAAQS by the end of the sixth calendar year following the date of designation of the area with the implementation of RACM and RACT and additional reasonable measures, the control strategies modeled as part of the attainment demonstration shall be consistent with control strategy requirements under § 51.1009(b).

(5) Required time frame for obtaining emissions reductions. For each Moderate nonattainment area, the attainment plan must provide for implementation of all control measures needed for attainment as expeditiously as practicable. All control measures in the attainment demonstration must be implemented no later than the beginning of the year containing the applicable attainment date, notwithstanding RACM implementation deadline requirements in § 51.1009.

(b) Nonattainment areas reclassified as Serious. The attainment demonstration due to the EPA as part of a Serious area attainment plan required under § 51.1003(b) or (c) shall meet all of the following criteria:

(1) The attainment demonstration shall show the projected attainment date for the Serious nonattainment area that is as expeditious as practicable.

(2) The attainment demonstration shall meet the requirements of Appendix W of this part and shall include inventory data, modeling results, and emission reduction analyses on which the state has based its projected attainment date.

(3) The base year for the emissions inventories required for attainment demonstrations under this paragraph shall be one of the 3 years used for designations or another technically appropriate inventory year if justified by the state in the plan submission.

(4) The control strategies modeled as part of a Serious area attainment demonstration shall be consistent with the control strategies required pursuant to § 51.1003 and § 51.1010.

(5) Required timeframe for obtaining emissions reductions. For each Serious nonattainment area, the attainment plan must provide for implementation of all control measures needed for attainment as expeditiously as practicable. All control measures must be implemented no later than the beginning of the year containing the applicable attainment date, notwithstanding BACM implementation deadline requirements in § 51.1010.

(a) Each attainment plan for a PM2.5 nonattainment area shall include an RFP plan that demonstrates that sources in the area will achieve such annual incremental reductions in emissions of direct PM2.5 and PM2.5 plan precursors as are necessary to ensure attainment of the applicable PM2.5 NAAQS as expeditiously as practicable. The RFP plan shall include all of the following:

(1) A schedule describing the implementation of control measures during each year of the applicable attainment plan. Control measures for Moderate area attainment plans are required in § 51.1009, and control measures for Serious area attainment plans are required in § 51.1010.

(2) RFP projected emissions for direct PM2.5 and all PM2.5 plan precursors for each applicable milestone year, based on the anticipated implementation schedule for control measures required in paragraph (a)(1) of this section. For purposes of establishing motor vehicle emissions budgets for transportation conformity purposes (as required in 40 CFR part 93) for a PM2.5 nonattainment area, the state shall include in its RFP submission an inventory of on-road mobile source emissions in the nonattainment area for each milestone year.

(3) An analysis that presents the schedule of control measures and estimated emissions changes to be achieved by each milestone year, and that demonstrates that the control strategy will achieve reasonable progress toward attainment between the applicable base year and the attainment year. The analysis shall rely on information from the base year inventory for the nonattainment area required in § 51.1008(a)(1) and the attainment projected inventory for the nonattainment area required in § 51.1008(a)(2), in addition to the RFP projected emissions required in paragraph (a)(2) of this section.

(4) An analysis that demonstrates that by the end of the calendar year for each milestone date for the area determined in accordance with § 51.1013(a), pollutant emissions will be at levels that reflect either generally linear progress or stepwise progress in reducing emissions on an annual basis between the base year and the attainment year. A demonstration of stepwise progress must be accompanied by appropriate justification for the selected implementation schedule.

(5) At the state's election, an analysis that identifies air quality targets associated with the RFP projected emissions identified for the milestone years at the design value monitor locations.

(b) For a multi-state or multi-jurisdictional nonattainment area, the RFP plans for each state represented in the nonattainment area shall demonstrate RFP on the basis of common multi-state inventories. The states or jurisdictions within which the area is located must provide a coordinated RFP plan. Each state in a multi-state nonattainment area must ensure that the sources within its boundaries comply with enforceable emission levels and other requirements that in combination with the reductions planned in other state(s) within the nonattainment area will provide for attainment as expeditiously as practicable and demonstrate RFP consistent with these regulations.

(a) Consistent with CAA section 189(c)(1), the state must submit in each attainment plan for a PM2.5 nonattainment area specific quantitative milestones that demonstrate reasonable further progress toward attainment of the applicable PM2.5 NAAQS in the area and that meet the following requirements:

(1) Nonattainment areas initially classified as Moderate. (i) Except as provided in paragraph (a)(4) of this section, each attainment plan submittal for a Moderate PM2.5 nonattainment area shall contain quantitative milestones to be achieved no later than a milestone date of 4.5 years and 7.5 years from the date of designation of the area.

(ii) The plan shall contain quantitative milestones to be achieved by the milestone dates specified in paragraph (a)(1)(i) of this section, as applicable, and that provide for objective evaluation of reasonable further progress toward timely attainment of the applicable PM2.5 NAAQS in the area. At a minimum, each quantitative milestone plan must include a milestone for tracking progress achieved in implementing the SIP control measures, including RACM and RACT, by each milestone date.

(2) Nonattainment areas reclassified as Serious. (i) Except as provided in paragraph (a)(4) of this section, each attainment plan submission that demonstrates that a Serious PM2.5 nonattainment area can attain a particular PM2.5 NAAQS by the end of the tenth calendar year following the effective date of designation of the area with the implementation of control measures as required under § 51.1010(a) shall contain quantitative milestones to be achieved no later than milestone dates of 7.5 years and 10.5 years, respectively, from the date of designation of the area.

(ii) Except as provided in paragraph (a)(4) of this section, each attainment plan submission that demonstrates that a Serious PM2.5 nonattainment area cannot practicably attain a particular PM2.5 NAAQS by the end of the tenth calendar year following the date of designation of the area with the implementation of control measures required under § 51.1010(a) shall contain quantitative milestones to be achieved no later than milestone dates of 7.5 years, 10.5 years, and 13.5 years from the date of designation of the area. If the attainment date is beyond 13.5 years from the date of designation of the area, such attainment plan shall also contain a quantitative milestones to be achieved no later than milestone dates of 16.5 years, respectively, from the date of designation of the area.

(iii) The plan shall contain quantitative milestones to be achieved by the milestone dates specified in paragraphs (a)(2)(i) and (ii) of this section, as applicable, and that provide for objective evaluation of reasonable further progress toward timely attainment of the applicable PM2.5 NAAQS in the area. At a minimum, each quantitative milestone plan must include a milestone for tracking progress achieved in implementing SIP control measures, including BACM and BACT, by each milestone date.

(3) Serious areas that fail to attain by the applicable Serious area attainment date. (i) Except as provided in paragraph (a)(4) of this section, each attainment plan submission for a Serious area that failed to attain a particular PM2.5 NAAQS by the applicable Serious area attainment date and is therefore subject to the requirements of CAA section 189(d) and § 51.1003(c) shall contain quantitative milestones.

(A) If the attainment plan is due prior to a date 13.5 years from designation of the area, then the plan shall contain milestones to be achieved by no later than a milestone date of 13.5 years from the date of designation of the area, and every 3 years thereafter, until the milestone date that falls within 3 years after the applicable attainment date.

(B) If the attainment plan is due later than a date 13.5 years from designation of the area, then the plan shall contain milestones to be achieved by no later than a milestone date of 16.5 years from the date of designation of the area, and every 3 years thereafter, until the milestone date that falls within 3 years after the applicable attainment date.

(ii) The plan shall contain quantitative milestones to be achieved by the milestone dates for the area, and that provide for objective evaluation of reasonable further progress toward timely attainment of the applicable PM2.5 NAAQS in the area. At a minimum, each quantitative milestone plan must include a milestone for tracking progress achieved in implementing the SIP control measures by each milestone date.

(4) Each attainment plan submission for an area designated nonattainment for the 1997 and/or 2006 PM2.5 NAAQS before January 15, 2015, shall contain quantitative milestones to be achieved no later than 3 years after December 31, 2014, and every 3 years thereafter until the milestone date that falls within 3 years after the applicable attainment date.

(b) Not later than 90 days after the date on which a milestone applicable to a PM2.5 nonattainment area occurs, each state in which all or part of such area is located shall submit to the Administrator a milestone report that contains all of the following:

(1) A certification by the Governor or Governor's designee that the SIP control strategy is being implemented consistent with the RFP plan, as described in the applicable attainment plan;

(2) Technical support, including calculations, sufficient to document completion statistics for appropriate milestones and to demonstrate that the quantitative milestones have been satisfied and how the emissions reductions achieved to date compare to those required or scheduled to meet RFP; and,

(3) A discussion of whether the area will attain the applicable PM2.5 NAAQS by the projected attainment date for the area.

(c) If a state fails to submit a milestone report by the date specified in paragraph (b) of this section, the Administrator shall require the state to submit, within 9 months after such failure, a plan revision that assures that the area will achieve the next milestone or attain the applicable NAAQS by the applicable date, whichever is earlier. If the Administrator determines that an area has not met any applicable milestone by the milestone date, the state shall submit, within 9 months after such determination, a plan revision that assures that the area will achieve the next milestone or attain the applicable NAAQS by the applicable date, whichever is earlier.

(a) The state must include as part of each attainment plan submitted under this subpart for a PM2.5 nonattainment area specific contingency measures that shall take effect with minimal further action by the state or the EPA following a determination by the Administrator that the area has failed:

(1) To meet any RFP requirement in an attainment plan approved in accordance with § 51.1012;

(2) To meet any quantitative milestone in an attainment plan approved in accordance with § 51.1013;

(3) To submit a quantitative milestone report required under § 51.1013(b); or,

(4) To attain the applicable PM2.5 NAAQS by the applicable attainment date.

(b) The contingency measures adopted as part of a PM2.5 attainment plan shall meet all of the following requirements:

(1) The contingency measures shall consist of control measures that are not otherwise included in the control strategy or that achieve emissions reductions not otherwise relied upon in the control strategy for the area; and,

(2) Each contingency measure shall specify the timeframe within which its requirements become effective following a determination by the Administrator under paragraph (a) of this section.

(c) The attainment plan submission shall contain a description of the specific trigger mechanisms for the contingency measures and specify a schedule for implementation.

(a) Nonattainment areas initially classified as Moderate. Upon a determination by the EPA that a Moderate PM2.5 nonattainment area has attained the PM2.5 NAAQS, the requirements for the state to submit an attainment demonstration, provisions demonstrating that reasonably available control measures (including reasonably available control technology for stationary sources) shall be implemented no later than 4 years following the date of designation of the area, reasonable further progress plan, quantitative milestones and quantitative milestone reports, and contingency measures for the area shall be suspended until such time as:

(1) The area is redesignated to attainment, after which such requirements are permanently discharged; or,

(2) The EPA determines that the area has re-violated the PM2.5 NAAQS, at which time the state shall submit such attainment plan elements for the Moderate nonattainment area by a future date to be determined by the EPA and announced through publication in the Federal Register at the time EPA determines the area is violating the PM2.5 NAAQS.

(b) Nonattainment areas reclassified as Serious. Upon a determination by the EPA that a Serious PM2.5 nonattainment area has attained the PM2.5 NAAQS, the requirements for the state to submit an attainment demonstration, reasonable further progress plan, quantitative milestones and quantitative milestone reports, and contingency measures for the area shall be suspended until such time as:

(1) The area is redesignated to attainment, after which such requirements are permanently discharged; or,

(2) The EPA determines that the area has re-violated the PM2.5 NAAQS, at which time the state shall submit such attainment plan elements for the Serious nonattainment area by a future date to be determined by the EPA and announced through publication in the Federal Register at the time the EPA determines the area is violating the PM2.5 NAAQS.

All control requirements associated with a FIP or approved SIP in effect for an area pursuant to obligations arising from CAA section 110(a)(2)(D)(i) and (ii) as of October 24, 2016, such as the CAIR or the CSAPR, shall continue to apply after revocation of the 1997 primary annual PM2.5 NAAQS. Control requirements associated with a FIP or approved into the SIP pursuant to obligations arising from CAA section 110(a)(2)(D)(i) and (ii), including 40 CFR 51.123, 51.124, 52.35, 52.36, 52.38 and 52.39, may be modified by the state only if the requirements of § 51.123, 51.124, 52.35, 52.36, 52.38 and 52.39, including statewide annual SO2 and annual NOX emission budgets, continue to be in effect. Any such modification must meet the requirements of CAA section 110(l).