Atmospherically derived organic films on impervious surfaces, detection and characterization

grantor: University of TorontoThe hypothesis that organic films exist on impervious surfaces was investigated by collecting samples from windows in two cities and along an urban-rural gradient. Toronto samples showed 100 mg/m2 of material; n-alkane, PAH, PCB and PCA concentrations of 7500, 6100, 95 and 200 ng/m2, respectively; and aged SOC patterns relative to urban air. Film-air partition coefficients were comparable to KOA, suggesting partitioning of atmospheric compounds. Rural mass, thickness, and SOC concentrations were 2-35% of urban values, indicating that organic films are enhanced in urban and present in rural environments. Toronto SOC patterns were replicated with concentrations up to 3-fold greater in Baltimore films, suggesting these films are widespread. The effects of rain were investigated using simulated rainfall experiments. Approximately 75% of the total PAH and total PCB were non-preferentially removed, suggesting that the film contains surfactants, and film runoff may cause shock loading of SOCs to receiving waters.M.Sc