---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC/part51/subpartAA"
level: "subpart"
label: "Subpart AA"
heading: "Provisions for Implementation of the 2008 Ozone National Ambient Air Quality Standards"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC-part51-subpartAA"
sections_count: 20
---

# Subpart AA — Provisions for Implementation of the 2008 Ozone National Ambient Air Quality Standards

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter C — Air Programs › Part 51 — Requirements for Preparation, Adoption, and Submittal of Implementation Plans

## Sections

- [§51.1100. Definitions.](/cfr/40/51.1100.md)
- [§51.1101. Applicability of part 51.](/cfr/40/51.1101.md)
- [§51.1102. Classification and nonattainment area planning provisions.](/cfr/40/51.1102.md)
- [§51.1103. Application of classification and attainment date provisions in CAA section 181 to areas subject to § 51.1102.](/cfr/40/51.1103.md)
- [§51.1104. Reserved](/cfr/40/51.1104.md)
- [§51.1105. Transition from the 1997 ozone NAAQS to the 2008 ozone NAAQS and anti-backsliding.](/cfr/40/51.1105.md)
- [§51.1106. Redesignation to nonattainment following initial designations.](/cfr/40/51.1106.md)
- [§51.1107. Determining eligibility for 1-year attainment date extensions for the 2008 ozone NAAQS under CAA section 181(a)(5).](/cfr/40/51.1107.md)
- [§51.1108. Modeling and attainment demonstration requirements.](/cfr/40/51.1108.md)
- [§51.1109. Reserved](/cfr/40/51.1109.md)
- [§51.1110. Requirements for reasonable further progress (RFP).](/cfr/40/51.1110.md)
- [§51.1111. Reserved](/cfr/40/51.1111.md)
- [§51.1112. Requirements for reasonably available control technology (RACT) and reasonably available control measures (RACM).](/cfr/40/51.1112.md)
- [§51.1113. Section 182(f) NO X exemption provisions.](/cfr/40/51.1113.md)
- [§51.1114. New source review requirements.](/cfr/40/51.1114.md)
- [§51.1115. Emissions inventory requirements.](/cfr/40/51.1115.md)
- [§51.1116. Requirements for an Ozone Transport Region.](/cfr/40/51.1116.md)
- [§51.1117. Fee programs for Severe and Extreme nonattainment areas that fail to attain.](/cfr/40/51.1117.md)
- [§51.1118. Suspension of SIP planning requirements in nonattainment areas that have air quality data that meet an ozone NAAQS.](/cfr/40/51.1118.md)
- [§51.1119. Applicability.](/cfr/40/51.1119.md)