{"data":{"id":"us/40-cfr-52.121","jurisdiction":"us","citation":"40 CFR 52.121","heading":"Classification of regions.","body":"The Arizona plan is evaluated on the basis of the following classifications:\nAQCR (constituent counties) Classifications\nPM SOX NO2 CO O3\nMaricopa Intrastate (Maricopa) I III III I I\nPima Intrastate (Pima) I III III III III\nNorthern Arizona Intrastate (Apache, Coconino, Navajo, Yavapai) I III III III III\nMohave-Yuma Intrastate (La Paz, Mohave, Yuma) I III III III III\nCentral Arizona Intrastate (Gila, Pinal) I IA III III I\nSoutheast Arizona Intrastate (Cochise, Graham, Greenlee, Santa Cruz) I IA 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 D—Arizona"],"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":"8f223b26e5173d79ef8fe3c1dbccb25c3871b7a36cbf27d376fc1dd36ce5d7d4","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-52.120","next":"us/40-cfr-52.122"},"notice":"GroundRules: Original legal text. Not legal advice."}