An extensive air pollutant monitoring program, including ground level and aerial sampling, was carried out in the Houston area during the month of July 1976. Measurements included ozone, oxides of nitrogen, PAN, methane, carbon monoxide, individual hydrocarbons (C2-C10), halocarbons, condensation nuclei, and visual distance plus numerous meteorological parameters. Specific areas of interest included (1) oxidant formation and transport within the Houston urban plume, (2) relationships between ozone layers aloft and the vertical temperature profile, (3) composition and effects of refinery and petrochemical emissions on the local Houston air mass, and (4) identification and quantitation of individual C2-C10 hydrocarbons in the Houston atmosphere. Results of this field program showed that the city of Houston serves as a strong pollutant source. Ozone concentrations were generally high in downwind areas. During the study period, there were no 'blanket' areas of ozone in southern Texas. Therefore, high oxidant levels observed in Houston are a direct result of the precursors emitted in the Houston area.