A technique to measure fine-dust emission potentials during wind erosion

Suspendable-size soil particles are released during wind erosion and transported downwind, impacting regional air quality. Of particular concern are those particles with a mean aerodynamic diameter of <10 μm (PM₁₀) and the finer subset of those <2.5 μm (PM_2.5). To estimate the air quality impact of wind erosion, the potential release from nondispersed soil of PM₁₀ and PM_2.5 particles must be quantified for both those readily entrained existing particles and those generated by aggregate abrasion. A new laboratory technique was devised to determine the potential emission of these size particles by both processes from nondispersed soil samples. An emission cone in which the soil sample was suspended and rotationally abraded in an air stream was coupled with a standard measuring instrument for either PM₁₀ or PM_2.5. Data of nondispersed soil samples compared with those dispersed showed significantly less emission potentials for the nondispersed. The PM_2.5 portion of the PM₁₀ values ranged from 30 to 55% indicating significant air quality impacts by wind erosion in this region based on either standard. Results from Washington State showed spatial patterns closely related to soil morphology, and a linear relationship between dispersed and self-abrader PM₁₀, but not PM_2.5.