---
kind: "section"
citation: "14 C.F.R. § 25.832"
title: "14"
number: "25.832"
heading: "Cabin ozone concentration."
url: "https://uscodex.org/cfr/14/25.832"
---

# §25.832. Cabin ozone concentration.

- (a) The airplane cabin ozone concentration during flight must be shown not to exceed—
  - (1) 0.25 parts per million by volume, sea level equivalent, at any time above flight level 320; and
  - (2) 0.1 parts per million by volume, sea level equivalent, time-weighted average during any 3-hour interval above flight level 270.
- (b) For the purpose of this section, “sea level equivalent” refers to conditions of 25 °C and 760 millimeters of mercury pressure.
- (c) Compliance with this section must be shown by analysis or tests based on airplane operational procedures and performance limitations, that demonstrate that either—
  - (1) The airplane cannot be operated at an altitude which would result in cabin ozone concentrations exceeding the limits prescribed by [paragraph (a)](#a) of this section; or
  - (2) The airplane ventilation system, including any ozone control equipment, will maintain cabin ozone concentrations at or below the limits prescribed by [paragraph (a)](#a) of this section.

## Notes

### Amendments

[Amdt. 25-50, 45 FR 3883, Jan. 1, 1980, as amended by Amdt. 25-56, 47 FR 58489, Dec. 30, 1982; Amdt. 25-94, 63 FR 8848, Feb. 23, 1998]

### Authority

Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702 and 44704; Pub. L. 115-254, 132 Stat 3281 (49 U.S.C. 44903 note).

### Source

Source: Docket No. 5066, 29 FR 18291, Dec. 24, 1964, unless otherwise noted.

### Amendments

[Amdt. 25-50, 45 FR 3883, Jan. 1, 1980, as amended by Amdt. 25-56, 47 FR 58489, Dec. 30, 1982; Amdt. 25-94, 63 FR 8848, Feb. 23, 1998]