# Approval and Promulgation of Air Quality Plans: State of Missouri
> **Rule** · Direct final rule. · Published 2011-07-21 · Effective 2011-09-19 · 76 FR 43598
## Document
- **Document number:** 2011-18176
- **Category:** air-emissions
- **Federal Register citation:** 76 FR 43598
- **CFR reference:** 40 CFR 52
- **Publication date:** 2011-07-21
- **Effective date:** 2011-09-19
- **State:** MO
- **EPA docket:** EPA-R07-OAR-2011-0451
## Abstract

EPA is approving an April 20, 2011, request from the State of Missouri to exempt sources of Nitrogen Oxides (NO<INF>X</INF>) in the Missouri portion of the St. Louis (MO-IL) metropolitan 8-hour ozone nonattainment area from the Clean Air Act (CAA) requirements for NO<INF>X</INF> Reasonably Available Control Technology (RACT) for purposes of attaining the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS). The Missouri NO<INF>X</INF> RACT waiver request for its portion of the St. Louis metropolitan 8-hour ozone nonattainment area is based on the most recent three years of complete, quality-assured ozone monitoring data, which demonstrate that additional reductions of NO<INF>X</INF> emissions in the Area would not contribute to attainment of the 1997 8-hour ozone NAAQS.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2011/07/21/2011-18176/approval-and-promulgation-of-air-quality-plans-state-of-missouri)
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