---
kind: "section"
citation: "40 C.F.R. § 51.1002"
title: "40"
number: "51.1002"
heading: "Classifications and reclassifications."
url: "https://uscodex.org/cfr/40/51.1002"
---

# §51.1002. Classifications and reclassifications.

- (a) **Initial classification as Moderate PM—** 2.5 nonattainment area. Any area designated nonattainment for a PM2.5 NAAQS shall be classified at the time of such designation, by operation of law, as a Moderate PM2.5 nonattainment area.
- (b) **Reclassification as Serious PM—** 2.5 nonattainment area. A Moderate nonattainment area shall be reclassified to Serious under the following circumstances:
  - (1) The EPA shall reclassify as Serious through notice-and-comment rulemaking any Moderate PM2.5 nonattainment area that the EPA determines cannot practicably attain a particular PM2.5 NAAQS by the applicable Moderate area attainment date.
  - (2) A Moderate PM2.5 nonattainment area shall be reclassified by operation of law as a Serious nonattainment area if the EPA finds through notice-and-comment rulemaking that the area failed to attain a particular PM2.5 NAAQS by the applicable Moderate area attainment date.

## Notes

### Source

Source: 81 FR 58151, Aug. 24, 2016, unless otherwise noted.

### Authority

Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.

### Source

Source: 36 FR 22398, Nov. 25, 1971, unless otherwise noted.