---
kind: "section"
citation: "40 C.F.R. § 1065.1123"
title: "40"
number: "1065.1123"
heading: "General provisions for determining exhaust opacity."
url: "https://uscodex.org/cfr/40/1065.1123"
---

# §1065.1123. General provisions for determining exhaust opacity.


The provisions of [§ 1065.1125](/cfr/40/1065.1125.md) describe system specifications for measuring percent opacity of exhaust for all types of engines. The provisions of [§ 1065.1127](/cfr/40/1065.1127.md) describe how to use such a system to determine percent opacity of engine exhaust for applications other than locomotives. See [40 CFR 1033.525](/cfr/40/1033.525.md) for measurement procedures for locomotives.


## Notes

### Source

Source: Sections 1065.1123 through 1065.1127 appear at 88 FR 4693, Jan. 24, 2023, unless otherwise noted.

### Source

Source: 79 FR 23820, Apr. 28, 2014, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401-7671q.

### Source

Source: 70 FR 40516, July 13, 2005, unless otherwise noted.