---
kind: "section"
citation: "40 C.F.R. § 1065.274"
title: "40"
number: "1065.274"
heading: "Zirconium dioxide (ZrO 2 ) NO X analyzer."
url: "https://uscodex.org/cfr/40/1065.274"
---

# §1065.274. Zirconium dioxide (ZrO 2 ) NO X analyzer.

- (a) **Application.** You may use a zirconia oxide (ZrO2) analyzer to measure NOX in raw exhaust for field-testing engines.
- (b) **Component requirements.** We recommend that you use a ZrO2 analyzer that meets the specifications in Table 1 of [§ 1065.205](/cfr/40/1065.205.md). Note that your ZrO2-based system must meet the linearity verification in [§ 1065.307](/cfr/40/1065.307.md).
- (c) **Species measured.** The ZrO2-based system must be able to measure and report NO and NO2 together as NOX. If the ZrO2-based system cannot measure all of the NO2, you may develop and apply correction factors based on good engineering judgment to account for this deficiency.
- (d) **Interference.** You must account for NH3 interference with the NOX measurement.

## Notes

### Amendments

[88 FR 4673, Jan. 24, 2023]

### Authority

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

### Source

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

### Amendments

[88 FR 4673, Jan. 24, 2023]