{"data":{"id":"us/40-cfr-52.1021","jurisdiction":"us","citation":"40 CFR 52.1021","heading":"Classification of regions.","body":"The Maine plan was evaluated on the basis of the following classifications:\nAir quality control region Pollutant\nParticulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone\nMetropolitan Portland Intrastate I II III III III\nAndroscoggin Valley Interstate IA IA III III III\nDown East Intrastate IA IA III III III\nAroostook Intrastate III III III III III\nNorthwest Maine Intrastate III III III III III","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER C—AIR PROGRAMS","PART 52—APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS","Subpart U—Maine"],"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":"53b4d04a106f218a3ac50e5abb0887a82610ff7588086b36bc9fda8a70e36a77","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-52.1020","next":"us/40-cfr-52.1022"},"notice":"GroundRules: Original legal text. Not legal advice."}