Accurate measurements of atmospheric concentration of non-methane organic compounds (NMOC) are necessary in the application of photochemical models that are used by states in developing the control strategies needed to achieve compliance with ambient air quality standards for ozone. NMOC measurements obtained with available continuous NMOC analyzers have often been of inadequate quality. Speciated gas chromotographic measurements, though adequate, are excessively difficult and expensive where speciated data are not needed. A simplified cryogenic preconcentration, direct flame ionization detection (PDFID) method that is sensitive and provides accurate measurements of ambient NMOC concentrations has been developed and standardized sufficiently to be recommended for use by state and local air pollution control agencies in the development of their ozone control plans. Recent refinements to the method are discussed, an automatic remote sampling system is described, and the performance (precision and accuracy) of the method is characterized, based on results from utilization of the method for NMOC analysis of 1375 air samples collected from 22 sites during the summer of 1984. A complete description of the method is also provided in an appendix.

At head of title: Project summary. "October 1985."