# Approval and Promulgation of Implementation Plans; State of Missouri
> **Rule** · Direct final rule. · Published 2003-03-18 · Effective 2003-05-19 · 68 FR 12829
## Document
- **Document number:** 03-6311
- **Category:** air-emissions
- **Federal Register citation:** 68 FR 12829
- **CFR reference:** 40 CFR 52
- **Publication date:** 2003-03-18
- **Effective date:** 2003-05-19
- **State:** MO
- **EPA docket:** MO 176-1176a
## Abstract

EPA is announcing it is approving a revision to the Missouri State Implementation Plan (SIP) which pertains to updating the state's Air Quality Index (AQI) rule to make it consistent with the Federal rule. The AQI is used by states for daily air quality reporting to the general public. Approval of this revision will ensure consistency between the state and Federally-approved rules, and ensure Federal enforceability of the revised state rule.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2003/03/18/03-6311/approval-and-promulgation-of-implementation-plans-state-of-missouri)
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