Submitted to: Air and Waste Management Annual Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/8/1998
Publication Date: N/A
Interpretive Summary: Urban areas on the Columbia Plateau of Eastern Washington, Northern Oregon and the Idaho Panhandle have exceeded the fugitive dust PM10 (fine dust less than 10 microns in diameter) standard numerous times since measurements were started in 1985, with several of these occasions occurring on days of obvious regional agricultural wind erosion. Although the physical processes contributing to wind erosion and its control throug agricultural practices are reasonably well understood, the predictive methods currently in use were not designed to estimate dust emissions. Thus, the Columbia Plateau was chosen as a region to study relationships between PM10 particulate pollution and agricultural field wind erosion. The susceptibility of a particular field to wind erosion and dust emission depends greatly on farming operations, the field soil and its condition, the crop growth and recent weather. A model to predict wind erosion and dust emissions depending on these various conditions has been developed.
Technical Abstract: Many urban areas, particularly in the Western U.S., have experienced concentrations of fugitive dust particulates from up-wind sources, which exceeded federal health standards. In many of these cases, it was evident that a significant amount of this material was generated on agricultural fields during wind erosion, entrained and transported in the regional air mass. Thus both the soil resource and the air quality in downwind urban regions are degraded. The Pacific Northwest Columbia Plateau of eastern Washington, northern Oregon and northern Idaho is a broad, relatively flat loessial plateau of over 136,000 square kilometers which was selected for a regional scale study. This area is characterized by very erosive soils, mostly dryland farming and several urban regions experiencing air quality concerns due to particulates. The loess soils of the study region are highly erodible and contain signficant amounts of free dust particulates less than 10 and less than 2.5 microns diameter, which readily become suspended and travel many kilometers downwind during wind erosion events. Soil, vegetation and climatic variables were combined into empirical wind erosion and fugitive dust emission relationships. The emissions model was combined with a comprehensive transport/dispersion model to predict downwind urban concentrations and evaluate the relative effectiveness of selected farm-level controls.