Document Center is acquired by Nimonik

1.1 This test method2 presents a procedure for sampling and determination of non-methane organic compounds (NMOC) in ambient, indoor, or workplace atmospheres.

1.2 This test method describes the collection of integrated whole air samples in silanized or other passivated stainless steel canisters, and their subsequent laboratory analysis.

1.3 This test method employs a cryogenic trapping procedure for concentration of the NMOC prior to analysis.

1.4 This test method describes the determination of the NMOC by the flame ionization detection (FID), without the use of gas chromatographic columns and other procedures necessary for species separation.

1.5 The range of this test method is from 20 ppb C to 10 000 ppb C (1, 2).3

1.6 This test method has a larger uncertainty for some halogenated or oxygenated hydrocarbons than for simple hydrocarbons or aromatic compounds. This is especially true if there are high concentrations of chlorocarbons or chlorofluorocarbons present.

1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.

1.8 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 Many regulators, industrial processes, and other stakeholders require determination of NMOC in atmospheres.

5.2 Accurate measurements of ambient NMOC concentrations are critical in devising air pollution control strategies and in assessing control effectiveness because NMOCs are primary precursors of atmospheric ozone and other oxidants (7, 8).

5.3 Conventional test methods based upon gas chromatography and qualitative and quantitative species evaluation are relatively time consuming, sometimes difficult and expensive in staff time and resources, and are not needed when only a measurement of NMOC is desired. The test method described requires only a simple, cryogenic pre-concentration procedure followed by direct detection with an FID. This test method provides a sensitive and accurate measurement of ambient total NMOC concentrations where speciated data are not required. Typical uses of this standard test method are as follows.

5.4 An application of the test method is the monitoring of the cleanliness of canisters.

5.5 Another use of the test method is the screening of canister samples prior to analysis.

5.6 Collection of ambient air samples in pressurized canisters provides the following advantages: