PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES
- SUBPART A—Meaning of Terms (§81.1 to §81.1)
- SUBPART B—Designation of Air Quality Control Regions (§81.11 to §81.275)
- SUBPART C—Section 107 Attainment Status Designations (§81.300 to §81.356)
- SUBPART D—Identification of Mandatory Class I Federal Areas Where Visibility Is an Important Value (§81.400 to §81.437)