# Revisions to the Arizona State Implementation Plan, Maricopa County Air Quality Department
> **Rule** · Direct final rule. · Published 2009-10-14 · Effective 2009-12-14 · 74 FR 52693
## Document
- **Document number:** E9-24549
- **Category:** air-emissions
- **Federal Register citation:** 74 FR 52693
- **CFR reference:** 40 CFR 52
- **Publication date:** 2009-10-14
- **Effective date:** 2009-12-14
- **State:** AZ
- **EPA docket:** EPA-R09-OAR-2009-0339
## Abstract

EPA is taking direct final action to approve revisions to the Maricopa County Air Quality Department (MCAQD) portion of the Arizona State Implementation Plan (SIP). These revisions concern particulate matter (PM) emissions and precursors from steam generating units, cogeneration units, stationary gas turbines, process heaters and internal combustion engines. We are approving local rules that regulate these emission sources under the Clean Air Act as amended in 1990 (CAA or the Act).

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2009/10/14/E9-24549/revisions-to-the-arizona-state-implementation-plan-maricopa-county-air-quality-department)
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