Data / Federal rules / 2026-16515
Air Plan Approval; Missouri; Clean Data Determination for the 2015 8-Hour Ozone Standard for the Missouri Portion of the St. Louis Nonattainment Area
The Environmental Protection Agency published this final rule in the Federal Register on August 13, 2026. It took effect on September 14, 2026.
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What the agency says
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.
Key facts
- Document number
- 2026-16515
- Type
- Final rule
- Action
- Final rule
- Agency
- Environmental Protection Agency
- Published
- August 13, 2026
- Takes effect
- September 14, 2026
- Dates
- This final rule is effective on September 14, 2026.
- Docket
- EPA-R07-OAR-2026-0463; FRL-13204-02-R7
- Code of Federal Regulations
- 40 CFR 52
- Topics
- Air pollution control; Environmental protection; Incorporation by reference; Intergovernmental relations; Nitrogen dioxide; Ozone; Reporting and recordkeeping requirements; Volatile organic compounds
- Pages
- 4
Other documents from the Environmental Protection Agency
Everything from the Environmental Protection Agency · Rules on air pollution control · Rules on environmental protection · Rules on incorporation by reference · Published in August 2026
Read from the Federal Register API, last updated 2026-10-24. The document on federalregister.gov is the official record; dates and dockets can change through later corrections. Free to reuse with credit to SpecStream under CC BY 4.0.