---
kind: "section"
citation: "40 C.F.R. § 1066.610"
title: "40"
number: "1066.610"
heading: "Dilution air background correction."
url: "https://uscodex.org/cfr/40/1066.610"
---

# §1066.610. Dilution air background correction.

- (a) **Correct the emissions in a gaseous sample for background using the following equation—**
- (c) Determine the dilution factor, DF, over the test interval for partial-flow dilution sample systems using the following equation:
- (d) Determine the time-weighted dilution factor, DFw, over the duty cycle using the following equation:

## Notes

### Amendments

[79 FR 23823, Apr. 28, 2014, as amended at 86 FR 34583, June 29, 2021]

### Authority

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

### Source

Source: 79 FR 23823, Apr. 28, 2014, unless otherwise noted.

### Amendments

[79 FR 23823, Apr. 28, 2014, as amended at 86 FR 34583, June 29, 2021]