AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Influence of Urban Aerosols on the Chemistry of Stormwater Runoff from Building Roofs
ALEXANDER JOHNSON, Cliff Davidson, Syracuse University
Abstract Number: 82 Working Group: Urban Aerosols
Abstract Atmospheric aerosols are continually depositing onto urban surfaces such as streets, sidewalks, lawns, and building roofs. A fraction of these deposited aerosols are mobilized during rainstorms and may contaminate stormwater runoff. However, not much is known about the origins of the chemical constituents. Besides washoff of dry deposited aerosol, other possible sources of contaminants include chemical species in the falling rain (wet deposition), washoff of debris from the surface, erosion of surface coatings, and erosion of the surface material itself. In these experiments, we investigated the chemical composition of stormwater runoff from two adjacent rooftops: a 1.5 acre green roof on the Onondaga County Convention Center and a similarly sized traditional roof on the War Memorial Sports Arena, both located in downtown Syracuse, New York. The primary objective was to compare concentrations of different chemical species in runoff samples collected from both roofs to determine if the green roof acted as a filter to remove species from stormwater runoff or if the growth medium and vegetation on the green roof contributed to contamination. A second objective was to determine the relative contributions of wet deposition and dry deposition as well as debris and surface erosion to runoff contamination from both roofs. Falling rain was collected and analyzed for the same chemical species to determine the contribution of contamination from wet deposition. For dry deposition, fluxes of aerosols onto aerodynamic surfaces during antecedent dry weather were determined as a surrogate for deposition onto the roofs. The flux for each metal was multiplied by the duration of the antecedent dry period and surface area of the roof to obtain the dry deposition mass loading. Ambient airborne concentrations were also measured. All of these data were used to develop a model for contaminants in stormwater runoff from the roofs.