Air Plan Approval; Illinois; Clean Data Determination for the Illinois Portion of the St.
The Environmental Protection Agency (EPA) is proposing to determine under the Clean Air Act (CAA) that the Illinois portion of the St. Louis, MO-IL nonattainment area (hereafter also referred to, respectively, as the "St. Louis area" or "area") has attained the 2015 ozone National Ambient Air Quality Standards (NAAQS o
| Agency | Environmental Protection Agency |
|---|---|
| Document type | Proposed Rule |
| Published | 2026-02-26 |
| Summary | The Environmental Protection Agency (EPA) is proposing to determine under the Clean Air Act (CAA) that the Illinois portion of the St. Louis, MO-IL nonattainment area (hereafter also referred to, respectively, as the "St. Louis area" or "area") has attained the 2015 ozone National Ambient Air Quality Standards (NAAQS or standard). This determination is based upon complete, quality-assured, and certified ambient air monitoring data for the 2023-2025 design value period showing that the Illinois portion of the area achieved attainment of the 2015 ozone NAAQS. This determination also relies on the EPA concurrence of an exceptional events request submitted by the Illinois Environmental Protectio |
| Document number | 2026-03846 |
| Official record | https://www.federalregister.gov/documents/2026/02/26/2026-03846/air-plan-approval-illinois-clean-data-determination-for-the-illinois-portion-of-the-st-louis-area |