{"data":{"id":"us/40-cfr-52.2471","jurisdiction":"us","citation":"40 CFR 52.2471","heading":"Classification of regions.","body":"The Washington plan was evaluated on the basis of the following classifications:\nAir quality control region Pollutant\nParticulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone\nEastern Washington-Northern Idaho Interstate I IA III III III\nNorthern Washington Intrastate II III III III III\nOlympic-Northwest Washington Intrastate II II III III III\nPortland Interstate I IA III III III\nPuget Sound Intrastate I IA III III I\nSouth Central Washington Intrastate I 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 WW—Washington"],"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":"1f19028cff9fb9edffffcdf28ea33532dae6ce3fe09b1a8e8bd6f0c2ff7d05d8","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-52.2470","next":"us/40-cfr-52.2472"},"notice":"GroundRules: Original legal text. Not legal advice."}