Abstract:Human health effects have been linked to airborne concentrations of fine particulate matter. One source of fine particulate matter in the atmosphere is resuspended soil dust from a variety of activities, including agricultural operations. We have established a method to measure the potential of soil to emit fugitive dust in the PM₁₀ or PM_2.5 size range. The method is repeatable, and provides an index of PM₁₀ or PM_2.5 dust that is highly correlated to the soil texture. The ratio of the PM_2.5 Index to the PM₁₀ Index produced by this method is similar to field observations of ambient PM_2.5 and PM₁₀ concentrations downwind of agricultural operations in the San Joaquin Valley of California. The PM_2.5 or PM₁₀ Index will be a more useful parameter to estimate the potential of a soil to emit fugitive dust than the currently used dry silt content of soil. Research is currently underway to relate the PM₁₀ and PM_2.5 Index to measured emission factors, accounting for soil moisture and type of agricultural operation, so that a more reliable predictive equation can be developed for agricultural practices.