{"data":{"id":"us/40-cfr-51.1002","jurisdiction":"us","citation":"40 CFR 51.1002","heading":"Classifications and reclassifications.","body":"(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.\n(b) Reclassification as Serious PM2.5 nonattainment area. A Moderate nonattainment area shall be reclassified to Serious under the following circumstances:\n(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.\n(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.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER C—AIR PROGRAMS","PART 51—REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS","Subpart Z—Provisions for Implementation of PM2.5 National Ambient Air Quality Standards"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"ce65358fcf4ea32b6ef37a4df7ca4cf797227ccc781cf24f9f6d4fcff9f3ffc0","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-51.1001","next":"us/40-cfr-51.1003"},"notice":"GroundRules: Original legal text. Not legal advice."}