Field and laboratory studies will be conducted to better understand the role of particulate phase organic compounds in atmospheric biogeochemical cycles. One principal objective of the research is the completion of the chemical analysis of aerosol samples that have already been collected as part of a study on rural oxidants and to perform multi-variate statistical analysis of the data. By way of further field studies, another objective is the further elucidation of the different factors that relate to the chemistry of vapor and particle phase organic compounds that have already been measured at an urban location in Boulder, Colorado, and a pristine site at Niwot Ridge, Colorado. A final objective is the characterization of nitrogen- and sulfur- containing organic constituents of tropospheric particulate and of the relationships of such compounds to atmospheric photolytic oxidation cycles. In these studies, hourly variations in the particulate phase organic composition will be determined using a low-volume sampling technique followed by chromatographic separation and sensitive detection. Proposed studies of nitrogen- and sulfur-containting organic constituents of particles will require the development of new analytical methods involving supercritical fluid extractions and selective detection by chemiluminescene techniques and atomic emission.
