---
kind: "section"
citation: "40 C.F.R. § 201.21"
title: "40"
number: "201.21"
heading: "Quantities measured."
url: "https://uscodex.org/cfr/40/201.21"
---

# §201.21. Quantities measured.


The quantities to be measured under the test conditions described below, are the A-weighted sound levels for “fast” or “slow” meter response as defined in the American National Standard S1.4-1971.


## Notes

### Authority

Authority: Noise Control Act of 1972, sec. 17(a), 86 Stat. 1234 (42 U.S.C. 4916(a)).

### Source

Source: 45 FR 1263, Jan. 4, 1980, unless otherwise noted.