# Finding of Failure To Attain the 1987 24-Hour PM10 Standard; Reclassification as Serious Nonattainment; Pinal County, Arizona
> **Rule** · Final rule. · Published 2020-06-24 · Effective 2020-07-24 · 85 FR 37756
## Document
- **Document number:** 2020-12827
- **Category:** air-emissions
- **Federal Register citation:** 85 FR 37756
- **CFR reference:** 40 CFR 81
- **Publication date:** 2020-06-24
- **Effective date:** 2020-07-24
- **State:** AZ
- **EPA docket:** EPA-R09-OAR-2020-0151
## Abstract

The Environmental Protection Agency (EPA) is taking final action to determine that the West Pinal County, Arizona nonattainment area did not attain the 1987 24-hour national ambient air quality standards (NAAQS or "standard") for particulate matter with a diameter of ten micrometers or smaller (PM<INF>10</INF>) by December 31, 2018, the statutory attainment date for the nonattainment area. This action is based on the EPA's calculation of the PM<INF>10</INF> design value for the nonattainment area over the 2016-2018 period, using complete, quality-assured, and certified PM<INF>10</INF> monitoring data. With this final determination that West Pinal County has failed to attain the PM<INF>10</INF> NAAQS by its attainment date, the Clean Air Act (CAA) section 188(b)(2) requires that the nonattainment area be reclassified to Serious by operation of law. Within 18 months from the effective date of this reclassification to Serious, the State must submit State Implementation Plan (SIP) revisions that comply with the statutory and regulatory requirements for Serious PM<INF>10</INF> nonattainment areas.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2020/06/24/2020-12827/finding-of-failure-to-attain-the-1987-24-hour-pm10-standard-reclassification-as-serious)
---
*AI Analytics · CC0 1.0*