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Enhancements to AERMOD's building downwash algorithms based on wind-tunnel and Embedded-LES modeling
Citation:
Monbureau, E., D. Heist, S. Perry, L. Brouwer, H. Foroutan, AND W. Tang. Enhancements to AERMOD's building downwash algorithms based on wind-tunnel and Embedded-LES modeling. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 179:321-330, (2018).
Impact/Purpose:
EPA recently promulgated new 1-hour nitrogen dioxide (NO2) and sulfur dioxide (SO2) National Ambient Air Quality Standards (NAAQS). These new standards are more stringent than previous NAAQS for NO2 (formerly based on an annual averaging period) and SO2 (formerly based on a 3-hour, 24-hour and annual averaging periods). These standards are expected to have a dramatic effect on New Source Review (NSR) air quality permitting by putting significantly increased demands on dispersion model accuracy, particularly for sources in urban areas with high background levels of these pollutants. The core of this research task is the development of dispersion modeling algorithms that alone or in combination with existing modeling tools will be used to improve the accuracy and efficiency of estimated ambient air pollutant concentration fields for near-field and urban-scale applications.
Description:
Knowing the fate of effluent from an industrial stack is important for assessing its impact on human health. AERMOD is one of several Gaussian plume models containing algorithms to evaluate the effect of buildings on the movement of the effluent from a stack. The goal of this study is to improve AERMOD's ability to accurately model important and complex building downwash scenarios by incorporating knowledge gained from a recently completed series of wind tunnel studies and complementary large eddy simulations of flow and dispersion around simple structures for a variety of building dimensions, stack locations, stack heights, and wind angles. This study presents three modifications to the building downwash algorithm in AERMOD that improve the physical basis and internal consistency of the model, and one modification to AERMOD's building pre-processor to better represent elongated buildings in oblique winds. These modifications are demonstrated to improve the ability of AERMOD to model observed ground-level concentrations in the vicinity of a building for the variety of conditions examined in the wind tunnel and numerical studies.
