40 CFR § 52.221 - Classification of regions.

---
identifier: "/us/cfr/t40/s52.221"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 52.221 - Classification of regions."
title_number: 40
title_name: "Protection of Environment"
section_number: "52.221"
section_name: "Classification of regions."
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"
---


# 52.221 Classification of regions.

The California plan was evaluated on the basis of the following classifications:

Table 1 to § 52.221

|  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- |
| Great Basin Valley Intrastate | I | III | III | III | III |
| Lake County Intrastate | II | III | III | III | I |
| Lake Tahoe Intrastate | II | III | III | I | III |
| Metropolitan Los Angeles Intrastate | I | III | III | I | I |
| Mountain Counties Intrastate | II | III | III | I | I |
| North Central Coast Intrastate | II | III | III | III | I |
| North Coast Intrastate | II | III | III | III | III |
| Northeast Plateau Intrastate | III | III | III | III | III |
| Sacramento Valley Intrastate | II | III | III | I | I |
| San Diego Intrastate | II | III | III | I | I |
| San Francisco Bay Area Intrastate | II | III | III | I | I |
| San Joaquin Valley Intrastate | II | III | III | I | I |
| South Central Coast Intrastate | III | III | III | III | I |
| Southeast Desert Intrastate | I | III | III | III | I |

[86 FR 16537, Mar. 30, 2021]