1.1 These test methods cover procedures for the continuous determination of total nitrogen dioxide (NO₂) and nitric oxide (NO) as NO_x, or nitric oxide (NO) alone or nitrogen dioxide (NO₂) alone, in the ranges shown in the following table:

Note 1 - Approximate range: 25°C and 101.3 kPa (1 atm).

1.2 The test methods are based on the chemiluminescent reaction between nitric oxide and ozone.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 9.