{"data":{"id":"us/40-cfr-52.671","jurisdiction":"us","citation":"40 CFR 52.671","heading":"Classification of regions.","body":"The Idaho plan was evaluated on the basis of the following classifications:\nAir quality control region Pollutants\nParticulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone\nEastern Idaho Intrastate I II III III III.\nEastern Washington Northern Idaho Interstate (Idaho) I II III III III.\nIdaho Intrastate I III III III III.\nMetropolitan Boise Intrastate II III III I 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 N—Idaho"],"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":"bc0253a9e62df1bd374f541b63d9ca6459367041079173be8ec3166637c1e5e5","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-52.670","next":"us/40-cfr-52.672"},"notice":"GroundRules: Original legal text. Not legal advice."}