A repository of 44 gaseous compounds including hydrocarbons, halocarbon, and sulfur species has been established under contract with the U.S. Environmental Protection Agency (USEPA). The main objectives of this on-going project are (1) to provide gas mixtures to EPA, state/local agencies, or their contractors, as performance audits to assess the accuracy of source emission measurements in 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, 29 compounds have been used to conduct 130 different audits. The results of these audits and a description of the experimental procedures used for analyses and available stability data are presented in the status report. Seventy percent of the audit results are within 15 percent of the expected values. Compound stabilities have been determined through multiple analyses of the cylinders containing them. Stability data for up to 6 years is available for many compounds and over 3 years for most compounds. Compounds that are unstable and not suitable for use as an audit material are identified.

Caption title. "October 1984." Includes bibliographical references. "EPA-600/4-84-079." Microfiche.