# Air Quality Designations for the 2010 Sulfur Dioxide (SO2) Primary National Ambient Air Quality Standard-Round 3
> **Rule** · Final rule. · Published 2018-01-09 · Effective 2018-04-09 · 83 FR 1098
## Document
- **Document number:** 2017-28423
- **Category:** air-emissions
- **Federal Register citation:** 83 FR 1098
- **CFR reference:** 40 CFR 81
- **Publication date:** 2018-01-09
- **Effective date:** 2018-04-09
- **EPA docket:** EPA-HQ-OAR-2017-0003
## Abstract

This final rule establishes the initial air quality designations for certain areas in the United States (U.S.) for the 2010 sulfur dioxide (SO<INF>2</INF>) primary National Ambient Air Quality Standard (NAAQS). The Environmental Protection Agency (EPA) is designating the areas as either Nonattainment, Attainment/ Unclassifiable, or Unclassifiable. The designations are based on application of the EPA's nationwide analytical approach and technical analysis, including evaluation of monitoring data and air quality modeling, to determine the appropriate designation based on the weight of evidence for each area. The Clean Air Act (CAA or Act) directs areas designated Nonattainment by this rule to undertake certain planning and pollution control activities to attain the SO<INF>2</INF> NAAQS as expeditiously as practicable. This is the third of four expected sets of actions to designate areas of the U.S. for the 2010 SO<INF>2</INF> NAAQS.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2018/01/09/2017-28423/air-quality-designations-for-the-2010-sulfur-dioxide-so2-primary-national-ambient-air-quality)
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