Fugitive Dust Generation in the Laboratory

Fugitive dust (dust composed of natural materials, suspended into the air by human activities) is an air quality concern in many agricultural regions of the United States. Fugitive dust is generated almost everywhere by vehicles traveling on unpaved or sediment-covered roads and at construction and waste management sites (Cowherd et al., 1988). In the Southern High Plains of Texas and the Columbia Plateau of Washington State, most fugitive dust is generated by wind erosion. In the San Joaquin Valley of California, agricultural operations on land surfaces are the primary source of fugitive dust. Generation, collection and measurement of dust in a controlled laboratory setting can be an important tool for determining the specific physical and chemical source characteristics of airborne particulate matter, regulated under United States Environmental Protection Agency PM10 (airborne particles smaller than 10 mm) and PM2.5 (particles smaller than 2.5 mm) standards, as well as by individual states and air pollution control agencies. There is extensive literature regarding the production and measurement of dust aerosols in the laboratory, although these publications generally reflect instruments and experiments not designed to investigate ambient fugitive dust. Most work has instead focused on process control or occupational hygiene in manufacturing (Heitbrink et al., 1990), inhalation toxicology (Shiotsuka et al., 1992), and the pharmaceutical industry (Hindle and Byron, 1995). Still, many techniques, equipment, and findings of these types of studies can be applied to research on atmospheric fugitive dust. Cowherd and Grelinger (1992) provided a good description of some laboratory systems used to generate and measure fugitive dust, while Gill et al. (in press) have developed a comprehensive review of the theory and practice of dust aerosol production in laboratory settings.