Special meteorological and air quality studies were conducted during August 1980 in the Piceance Creek Basin oil shale resource area of Northwestern Colorado as part of the EPA-sponsored Green River Ambient Model Assessment program. The objective of the limited field program was to collect initial data to aid in the development, calibration, and validation of a mesoscale air quality model. The specific goals of the program were to investigate the growth and characteristics of convective boundary layers that form over the area during the daytime, to characterize background pollutant levels, visibility, and atmospheric structure over the area, and to investigate, by means of tracer experiments, the dispersion and dry deposition of pollutants released in nocturnal valley drainage flows. An instrumented DC-3 aircraft was the primary means of collecting background air quality and visibility data. A balloon-borne upper air sounding system was used to monitor temporal changes in convective boundary layer structure. Dual tracer experiments were conducted on four occasions in the shallow Corral Gulch near tract C-a using non-depositing SF6 gas and depositing lithium-traced particles collected on two to five sampling arcs during well-defined drainage flow events.