Large fugitive dust plumes are often visible when wind speeds are high and when vehicles are moving over dusty surfaces. Fugitive dust originates from paved and unpaved roads, construction sites, agriculture tilling, landfills, mine tailings, application of de-icing materials, and general wind erosion, contributing more than 80% of PM10 and PM2.5 criteria contaminant emissions nationwide, with higher amounts in resource extraction regions. A portable wind tunnel was operated on stabilized and undisturbed surfaces that represent many of these sources. This sampling system determined the capacities of dust reservoirs, suspendable size distributions, emission rates as a function of wind speed, and chemical composition. A wide range of size distributions and sensitivity to wind speed was found. Dust suppression techniques, such as frequent watering, application of stabilizing compounds, and minimizing trackout onto paved roads, were effective in reducing dust emissions. N-alkanes and other organic compounds were enriched in surface dust for many unpaved roads, providing fingerprints that are applicable to apportioning ambient PM10 and PM2.5 concentrations to their fugitive dust sources.
Dr. John G. Watson is a Research Professor at the Desert Research Institute of the University of Nevada. His research involves the development and application of sampling and analysis methods for the real-world characterization of source emissions and ambient concentrations for inhalable aerosols. He has authored more than 300 publications on these topics over his past 35 year involvement in the environmental sciences.