Generation of accurate ambient air VOC pollutant measurement data as a basis for regulatory decisions is critical. Air methods available through the Environmental Protection Agency are contained in the 'Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air.' Some of the methods in this Compendium are developed and validated only in a single laboratory. Some represent a synthesis of the procedures performed in a number of laboratories. The range of applicability of the methods is defined only in general outline, with very little specific data available to assess the performance of the total methodology for a large number of compounds. There are many criteria which must be considered in the selection of methodology for ambient air sampling and analysis. Both canisters and sorbents may be used for Volatile Organic Compounds. There is considerable latitude regarding selection of analytical methodology: mass spectrometry, high performance liquid chromatography, and gas chromatography with a variety of detectors are used at various times for various reasons. Even the exact type of measurement to be taken will vary according to program needs and the ultimate use of the data. The quality of the air measurement data is also a function of the skill, competence, and experience of both the field study collection team and the laboratory which is executing the methodology. The paper presents examples of Radian Corporation's experience with ambient air measurement techniques.

"EPA 600/D-90/113."