{"data":{"id":"us/40-cfr-52.2021","jurisdiction":"us","citation":"40 CFR 52.2021","heading":"Classification of regions.","body":"The Pennsylvania plan was evaluated on the basis of the following classifications:\nAir quality control region Pollutant\nParticulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone (hydrocarbons)\nMetropolitan Philadelphia Interstate I I III I I\nNortheast Pennsylvania-Upper Delaware Valley Interstate I II III III III\nSouth Central Pennsylvania Intrastate I II III III III\nCentral Pennsylvania Intrastate I III III III III\nSouthwest Pennsylvania Intrastate I I III I I\nNorthwest Pennsylvania-Youngstown Interstate I II 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 NN—Pennsylvania"],"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":"b6d4a09519de5431439a01d10db0002ab4ff4645179ac53f388c37c34ea9d28e","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-52.2020","next":"us/40-cfr-52.2022"},"notice":"GroundRules: Original legal text. Not legal advice."}