40 CFR § 52.499 - Significant deterioration of air quality.

---
identifier: "/us/cfr/t40/s52.499"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 52.499 - Significant deterioration of air quality."
title_number: 40
title_name: "Protection of Environment"
section_number: "52.499"
section_name: "Significant deterioration of air quality."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "52"
part_name: "APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401"
cfr_part: "52"
---


# 52.499 Significant deterioration of air quality.

(a) The requirements of sections 160 through 165 of the Clean Air Act are not met, since the plan does not include approvable procedures for preventing the significant deterioration of air quality.

(b) Regulations for preventing significant deterioration of air quality. The provisions of § 52.21 except paragraph (a)(1) are hereby incorporated and made a part of the applicable State plan for the District of Columbia.

[43 FR 26410, June 19, 1978, as amended at 45 FR 52741, Aug. 7, 1980; 68 FR 11322, Mar. 10, 2003; 68 FR 74488, Dec. 24, 2003]