"September 1987." Includes bibliographical references : page 34. EPA Contract No.: Contract Number: 68-02-4125

The U.S. Environmental Protection AGency has evaluated the suitability of 45 gaseous compounds including hydrocarbons, halocarbons, oxygenated and sulfurous species for use as standards for measuring stationary source emissions. The main objectives of this on-going project are (1) to provide gas mixtures to EPA, state/local agencies, or their contractors, as performance audit standards to assess the accuracy of measuring source emissions from certain organic chemical manufacturing industries, (2) to corroborate the vendor's certified analysis of the gas mixtures by in-house analysis, (3) to determine the stability of the gas mixtures with time by in-house analysis, and (4) to explore the feasibility of new audit materials as requested by EPA. Thus far, 31 mixtures have been used to conduct 214 different audits. The results of these audits, a description of the experimental procedures used for analyses, and available stability data are presented in this status report. Compound stabilities have been determined through multiple analyses of the cylinders containing them. Stability data for up to 8 years is available for many compounds and over 5 years for most compounds. Compounds that are unstable and not suitable for use as an audit material are identified.