Air Plan Approval; Missouri; Clean Data Determination for the 2015 8-Hour Ozone Standard for the Missouri Portion of the St. Louis Nonattainment Area
Built by the Tribune's code from the Federal Register. No AI wrote this page. Published in the Federal Register Aug. 13, 2026. Document 2026-16515. Updated Nov. 7, 2026.
- What it does
The Environmental Protection Agency (EPA) is determining under the Clean Air Act (CAA) that the Missouri portion of the St. Louis, MO- IL bi-state nonattainment area has achieved clean data for the 2015 8- hour ozone National Ambient Air Quality Standard (NAAQS or standard). This determination of clean data is based upon complete, quality- assured, and certified ambient air monitoring data for the 2023-2025 design value period showing that the Missouri portion of the area achieved attainment of the 2015 ozone NAAQS. The 2023-2025 design value relies upon EPA concurrence on a portion of the exceptional events request as submitted by the Missouri Department of Natural Resources (MoDNR) on November 3, 2025, and concurred on by the EPA on January 27, 2026. The EPA is also approving Missouri's November 3, 2025, clean data determination request. This final clean data determination suspends the obligations of the State of Missouri to submit certain nonattainment area planning requirements for as long as the Missouri portion of the St. Louis area continues to attain the 2015 ozone NAAQS. In a separate action, the EPA is finalizing a similar determination for the Illinois portion of the St. Louis area.
The Environmental Protection Agency's summary, as published in the Federal Register.
- What changed in the regulation
1 part of Title 40 of the Code of Federal Regulations:
Wording on eCFR: the day before it took effect and from the day it took effect (first part listed).
- Compared with
The Environmental Protection Agency has published 243 final rules in 2026 so far, compared with 263 in all of 2025.
Counted by the Tribune from Federal Register records since Jan. 1, 2025.
- What happens next and when
This final rule is effective on September 14, 2026.
The agency's dates, word for word.
The record as published
| Document number | 2026-16515 |
|---|---|
| Action | Final rule. |
| Agencies | Environmental Protection Agency |
| Published | Aug. 13, 2026 |
| Effective date | Sept. 14, 2026 |
| Docket | EPA-R07-OAR-2026-0463 |
Source: the Federal Register (public domain). The document in the Federal Register