Zirconium dioxide (ZrO 2 ) NO X analyzer.

(a) Application. You may use a zirconia oxide (ZrO 2 ) analyzer to measure NO X in raw exhaust for field-testing engines. (b) Component requirements. We recommend that you use a ZrO 2 analyzer that meets the specifications in Table 1 of § 1065.205. Note that your ZrO 2 -based system must meet the linearity verification in § 1065.307. (c) Species measured. The ZrO 2 -based system must be able to measure and report NO and NO 2 together as NO X . If the ZrO 2 -based system cannot measure all of the NO 2 , you may develop and apply correction factors based on good engineering judgment to account for this deficiency. (d) Interference. You must account for NH 3 interference with the NO X measurement. [88 FR 4673, Jan. 24, 2023]