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§ 1065.274 Zirconium dioxide (ZrO<sub>2</sub>) NO<sub>X</sub> analyzer.

40 CFR 1065.274

  1. CFR
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  3. Title 40
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  5. Chapter I
  6. ›
  7. Part 1065
  8. ›
  9. Subpart C
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  11. Subject Group NO<sub>X</sub>, N<sub>2</sub>O, and NH<sub>3</sub> Measurements
  12. ›
  13. 40 CFR 1065.274
Citation40 CFR 1065.274
CorpusDaily eCFR
Displayed edition2026-04-15
Last updated2026-04-15

§ 1065.274 Zirconium dioxide (ZrO2) NOX 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. Note that your ZrO2-based system must meet the linearity verification in § 1065.307.

(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.

[88 FR 4673, Jan. 24, 2023]