# 40 C.F.R. § 52.04 (2026): Classification of regions

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_04

## Section

- **Citation:** 40 C.F.R. § 52.04 (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 A / § 52.04: § 52.04   Classification of regions.

## Text

Each subpart sets forth the priority classification, by pollutant, for each region in the State. Each plan for each region was evaluated according to the requirements of part 51 of this chapter applicable to regions of that priority.

## Nearby sections

- [40 C.F.R. § 52.01 (2026) § 52.01   Definitions.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_01.md)
- [40 C.F.R. § 52.02 (2026) § 52.02   Introduction.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_02.md)
- [40 C.F.R. § 52.04 (2026) § 52.04   Classification of regions.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_04.md)
- [40 C.F.R. § 52.05 (2026) § 52.05   Public availability of emission data.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_05.md)
- [40 C.F.R. § 52.06 (2026) § 52.06   Legal authority.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_06.md)
- [40 C.F.R. § 52.07 (2026) § 52.07   Control strategies.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_07.md)
- [40 C.F.R. § 52.08 (2026) § 52.08   Rules and regulations.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_08.md)
- [40 C.F.R. § 52.09 (2026) § 52.09   Compliance schedules.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_09.md)
- [40 C.F.R. § 52.10 (2026) § 52.10   Review of new sources and modifications.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_10.md)
- [40 C.F.R. § 52.11 (2026) § 52.11   Prevention of air pollution emergency episodes.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_11.md)
- [40 C.F.R. § 52.12 (2026) § 52.12   Source surveillance.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_12.md)
- [40 C.F.R. § 52.13 (2026) § 52.13   Air quality surveillance; resources; intergovernmental cooperation.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_13.md)
- [40 C.F.R. § 52.14 (2026) § 52.14   State ambient air quality standards.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_14.md)
- [40 C.F.R. § 52.15 (2026) § 52.15   Public availability of plans.](https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_15.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T40_P52_S52_04. Check the current official text before relying on it. Not legal advice.