(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. (1) Nonattainment areas initially classified as Moderate.

   1. (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.
   2. (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. (2) Nonattainment areas reclassified to Serious.

   1. (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.
   2. (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. (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. (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. (2) [Reserved]