# 40 C.F.R. § 52.1171 (2026): Classification of regions

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1171

## Section

- **Citation:** 40 C.F.R. § 52.1171 (2026)
- **Heading:** Classification of regions
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 40 CFR: Protection of Environment / Chapter I / Part 52 / Subpart X / § 52.1171: § 52.1171   Classification of regions.

## Text

The Michigan plan was evaluated on the basis of the following classifications: Air quality control region Pollutant Particulate matter Sulfur oxides Nitrogen dioxide Carbon monoxide Ozone Metropolitan Detroit-Port Huron Intrastate I I III III III Metropolitan Toledo Interstate I I III III I South Central Michigan Intrastate II II III III III South Bend-Elkhart (Indiana)-Benton Harbor (Michigan) Interstate I IA III III III Central Michigan Intrastate II III III III III Upper Michigan Intrastate III III III III III [37 FR 10873, May 31, 1972, as amended at 39 FR 16346, May 8, 1974; 45 FR 29801, May 6, 1980]

## Nearby sections

- [40 C.F.R. § 52.1170 (2026) § 52.1170   Identification of plan.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1170.md)
- [40 C.F.R. § 52.1171 (2026) § 52.1171   Classification of regions.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1171.md)
- [40 C.F.R. § 52.1172 (2026) § 52.1172   Approval status.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1172.md)
- [40 C.F.R. § 52.1173 (2026) § 52.1173   Control strategy: Particulates.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1173.md)
- [40 C.F.R. § 52.1174 (2026) § 52.1174   Control strategy: Ozone.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1174.md)
- [40 C.F.R. § 52.1175 (2026) § 52.1175   Compliance schedules.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1175.md)
- [40 C.F.R. § 52.1179 (2026) § 52.1179   Control strategy: Carbon monoxide.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1179.md)
- [40 C.F.R. § 52.1180 (2026) § 52.1180   Significant deterioration of air quality.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1180.md)
- [40 C.F.R. § 52.1181 (2026) § 52.1181   Interstate pollution.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1181.md)
- [40 C.F.R. § 52.1182 (2026) § 52.1182   State boards.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1182.md)
- [40 C.F.R. § 52.1183 (2026) § 52.1183   Visibility protection.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1183.md)
- [40 C.F.R. § 52.1184 (2026) § 52.1184   Small business stationary source technical and environmental compliance assistance program.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1184.md)
- [40 C.F.R. § 52.1185 (2026) § 52.1185   Control strategy: Carbon monoxide.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1185.md)
- [40 C.F.R. § 52.1186 (2026) § 52.1186   Interstate pollutant transport provisions; What are the FIP requirements for decreases in emissions of nitrogen oxides?](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1186.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_1171. Check the current official text before relying on it. Not legal advice.