§ 51.905 How do areas transition from the 1-hour NAAQS to the 1997 8-hour NAAQS and what are the anti-backsliding provisions?

(a) What requirements that applied in an area for the 1-hour NAAQS continue to apply after revocation of the 1-hour NAAQS for that area?—(1) 8-Hour NAAQS Nonattainment/1-Hour NAAQS Nonattainment. The following requirements apply to an area designated nonattainment for the 8-hour NAAQS and designated nonattainment for the 1-hour NAAQS at the time of designation for the 8-hour NAAQS for that area.

(i) The area remains subject to the obligation to adopt and implement the applicable requirements as defined in § 51.900(f), except as provided in paragraph (a)(1)(iii) of this section, and except as provided in paragraph (b) of this section.

(ii) If the area has not met its obligation to have a fully-approved attainment demonstration SIP for the 1-hour NAAQS, the State must comply with one of the following:

(A) Submit a 1-hour attainment demonstration no later than 1 year after designation;

(B) Submit a RFP plan for the 8-hour NAAQS no later than 1-year following designations for the 8-hour NAAQS providing a 5 percent increment of emissions reduction from the area's 2002 emissions baseline, which must be in addition to measures (or enforceable commitments to measures) in the SIP at the time of the effective date of designation and in addition to national or regional measures and must be achieved no later than 2 years after the required date for submission (3 years after designation).

(C) Submit an 8-hour ozone attainment demonstration no later than 1 year following designations that demonstrates attainment of the 8-hour NAAQS by the area's attainment date; provides for 8-hour RFP for the area out to the attainment date; and for the initial period of RFP for the area (between 2003–2008), achieve the emission reductions by December 31, 2007.

(iii) If the area has an outstanding obligation for an approved 1-hour ROP SIP, it must develop and submit to EPA all outstanding 1-hour ROP plans; where a 1-hour obligation overlaps with an 8-hour RFP requirement, the State's 8-hour RFP plan can be used to satisfy the 1-hour ROP obligation if the 8-hour RFP plan has an emission target at least as stringent as the 1-hour ROP emission target in each of the 1-hour ROP target years for which the 1-hour ROP obligation exists.

(2) 8–Hour NAAQS Nonattainment/1–Hour NAAQS Maintenance. An area designated nonattainment for the 8-hour NAAQS that is a maintenance area for the 1-hour NAAQS at the time of designation for the 8-hour NAAQS for that area remains subject to the obligation to implement the applicable requirements as defined in § 51.900 (f) to the extent such obligations are required by the approved SIP, except as provided in paragraph (b) of this section. Applicable measures in the SIP must continue to be implemented; however, if these measures were shifted to contingency measures prior to designation for the 8-hour NAAQS for the area, they may remain as contingency measures, unless the measures are required to be implemented by the CAA by virtue of the area's requirements under the 8-hour NAAQS. The State may not remove such measures from the SIP.