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United States Department of Agriculture

Agricultural Research Service

Title: Influence of Area Source Shape and Orientation on the Spatial Variation of Emissions

item Stout, John

Submitted to: Proc First Inter Conf on Air Pollution from Agricultural Operations
Publication Type: Proceedings
Publication Acceptance Date: February 7, 1996
Publication Date: N/A

Interpretive Summary: As the wind sweeps across the surface of the earth it often encounters well-defined regions that provide an area source of gases or particulate matter. Emissions are transported by the wind across the source and develop into an increasingly concentrated low level plume that can adversely affect the local community. Plumes originating from area sources such as landfills, waste containment ponds, or cattle feedlots often contain noxious fumes. Wind-swept agricultural lands, construction sites, or dry lake beds may spawn plumes of fine dust particles. This paper represents an attempt to better describe the emissions upwind of a point within the boundaries of an area source by considering the influence of source shape and source orientation with respect to the wind. We further calculate the advection of emissions across the source. This effort represents a first step toward an improved area dispersion model.

Technical Abstract: An area source is assumed to emit gases or fine aerosols into the air above at a steady and uniform rate and the emissions are then advected downstream by the ambient wind. Analytical solutions are obtained for the variation of horizontal mass flow across rectangular and elliptical area sources. The rate at which the total mass flow increases with horizontal distance across sthe source is found to be a direct function of the source shape, the wind angle, and the aspect ratio of the source.

Last Modified: 4/18/2015
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