Code of Federal Regulations > Title 40 > Chapter I > Part 81 - PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES

U.S. Code of Federal Regulations

Regulations most recently checked for updates: Aug 27, 2025

Subpart A [§ 81.1 - § 81.1] - Subpart A—Meaning of Terms

Subpart B [§ 81.11 - § 81.276] - Subpart B—Designation of Air Quality Control Regions

Subpart C [§ 81.300 - § 81.356] - Subpart C—Section 107 Attainment Status Designations

Subpart D [§ 81.400 - § 81.437] - Subpart D—Identification of Mandatory Class I Federal Areas Where Visibility Is an Important Value

Subpart E [§ 81.455 - § 81.457] - Subpart E—Identification of Interstate Transport Regions