{"data":{"id":"us/40-cfr-52.621","jurisdiction":"us","citation":"40 CFR 52.621","heading":"Classification of regions.","body":"The Hawaii plan was evaluated on the basis of the following classifications:\nAir quality control region Pollutant\nParticulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Photochemical oxidants (hydrocarbons)\nState of Hawaii II 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 M—Hawaii"],"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":"9e3ad6fa0b6d9e1fed8c81118de7bf78d785e25d44bed4c169cee097444a70bf","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-52.620","next":"us/40-cfr-52.622"},"notice":"GroundRules: Original legal text. Not legal advice."}