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SIP Status and Information

Clean Data & Redesignation Policies

EPA has issued policy memoranda and implementation rules outlining EPA interpretations of the provisions of the Clean Air Act as they apply to areas that have attained the NAAQS. In designated nonattainment areas where monitored data demonstrate that the NAAQS have been achieved, EPA interprets certain requirements of the Clean Air Act as no longer applying for so long as air quality continues to meet the standard. Therefore, the Agency does not require these areas to submit to EPA certain SIP elements, including reasonable further progress (RFP) requirements, attainment demonstrations, reasonable available control measures (RACM), and contingency measures. This interpretation of the Clean Air Act is known as the Clean Data Policy.

The Clean Data Policy and Regulations

Under EPA's Clean Data Policy and the regulations that embody it, 40 CFR 51.918 (1997 8-hour ozone) and 51.1004(c) (PM25), an EPA rulemaking determination that an area is attaining the relevant standard suspends the area's obligations to submit an attainment demonstration, reasonable available control measures (RACM), reasonable further progress, contingency measures and other planning requirements related to attainment for as long as the area continues to attain. EPA's statutory interpretation of the Clean Data Policy is described in the "Final Rule to Implement the 8-hour Ozone National Ambient Air Quality Standard—Phase 2" (Phase 2 Final Rule). 70 FR 71612, 71644-46 (Nov. 29, 2005) (ozone); See also 72 FR 20586, 20665 (Apr. 25, 2007) (PM25). EPA believes that the legal basis set forth in detail in our Phase 2 Final rule, our May 10, 1995 memorandum (8 pp, 2,895k) from John S. Seitz, entitled "Reasonable Further Progress, Attainment Demonstration, and Related Requirements for Ozone Nonattainment Areas Meeting the Ozone National Ambient Air Quality Standard," and our December 14, 2004 memorandum (6 pp, 293k) from Stephen D. Page entitled "Clean Data Policy for the Fine Particle National Ambient Air Quality Standards" are equally pertinent to all NAAQS. EPA has codified the Clean Data Policy for 1997 8-hour ozone and PM25, and has also applied it in individual rulemakings for 1-hour ozone and PM10.

Under the Clean Data Policy, EPA may issue a determination of attainment (known informally as a Clean Data Determination) after notice and comment rulemaking determining that a specific area is attaining the relevant standard. For such areas the requirement to submit to EPA those SIP elements related to attaining the NAAQS is suspended for so long as the area continues to attain the standard. These planning elements include reasonable further progress (RFP) requirements, attainment demonstrations, RACM, contingency measures, and other state planning requirements related to attainment of the NAAQS. The determination of attainment is not equivalent to a redesignation, and the state must still meet the statutory requirements for redesignation in order to be redesignated to attainment. A determination of attainment for purposes of the Clean Data Policy/regulations is also not linked to any particular attainment deadline, and is not necessarily equivalent to a determination that an area has attained the standard by its applicable attainment deadline, e.g., under section 181(b).

Redesignation Guidance

One principal source of EPA guidance with respect to redesignations to attainment can be found in a memorandum entitled "Procedures for Processing Requests to Redesignate Areas to Attainment" (PDF) (13 pp, 812k) from John Calcagni, Director, Air Quality Management Division, September 4, 1992. It notes, for example, that, for the purposes of redesignation, a state must meet the applicable requirements of section 110 and Part D that become due prior to the state's submittal of a complete redesignation request to EPA. For the purposes of evaluating a redesignation request, the EPA will not need to consider the required SIP elements that became due after submittal of the redesignation request. However, such requirements remain due until EPA completes final action approving a redesignation request.

See the EPA Green Book website for comprehensive nonattainment area information for criteria pollutants. This website includes current area, state and county nonattainment and classification status, clean data determinations, redesignations, links to associated Federal Register Notices, GIS maps, and downloadable shapefiles and data exports.


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