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Regulations last checked for updates: May 15, 2025
Title 40 - Protection of Environment last revised: Nov 15, 2025
All Titles
Title 40
Chapter I
Part 81 - PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES
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
authority:
42 U.S.C. 7401
,
source:
36 FR 22421, Nov. 25, 1971, unless otherwise noted.
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