摘要: Currently available dispersion models used to estimate dispersion in urban areas were developed using data from experiments conducted at source-receptor distances ranging from 50 m to 16 km. The rural dispersion curves are based o... 展开 Currently available dispersion models used to estimate dispersion in urban areas were developed using data from experiments conducted at source-receptor distances ranging from 50 m to 16 km. The rural dispersion curves are based on the Prairie Grass experiment (Barad, 1958) where the source-receptor distances ranged from 50 m to 800 m. The urban dispersion curves are based on the St. Louis Dispersion Study (McElroy and Pooler, 1968) where the nearest receptor was 800 m from the source. Regulatory programs require the assessment of potential health impacts from exposures to air toxics from urban sources, such as gasoline stations, dry cleaners, and automotive repair facilities, where human receptors are typically within fifty meters from the source. Because such sources represent about 30,000 small businesses in California, there is a critical need to validate dispersion tools at this distance. ARB has responded to this need by sponsoring UCR to develop a new dispersion model that can be used to estimate the impact of urban sources at source-receptor distances of tens of meters. The model has been developed using data from the Prairie Grass experiment (Barad, 1958), and an experiment conducted in a model urban area at the Dugway Proving Ground, Utah. Estimates from the model proposed in this project have been compared with tracer concentrations measured under a variety of meteorological conditions in the vicinity of an urban source located at a parking lot on the College of Engineering, Center for Environmental Research and Technology (CE-CERT) at the University of California, Riverside. 收起