Grantee Research Project Results
The Resuspension of Dust and Contaminated Particles by AbrasionEPA Grant Number: U915192
Title: The Resuspension of Dust and Contaminated Particles by Abrasion
Investigators: Loosmore, Gwendolen
Institution: University of California - Berkeley
EPA Project Officer: Jones, Brandon
Project Period: January 1, 1997 through January 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Civil/Environmental Engineering
The objective of this research project is to develop and validate a new analytical model to predict the flux of resuspended dust and contaminated particles by abrasion. The movement of dust in the atmosphere provides a transport pathway for hazardous compounds, including asbestos, pathogenic organisms, and radionuclides. The resuspension flux of dust has been difficult to predict; scientists have relied on empirical approaches and parameters that vary widely among sites. A better model is needed for assessing the risk from contaminated locations (e.g., former nuclear test sites) and for incorporation into computer models that couple atmospheric and soil processes.Approach:
An analytical model has been developed to predict the abrasion-induced resuspension flux of contaminated dust from a heterogeneous soil on the small scale. The model incorporates the effect of the surface particle-size distribution on the abrasion collision. This dust-flux model can predict the total dust mass available for resuspension under specified meteorological conditions, as well as the dust flux before surface stabilization. The contaminant model incorporates the time dependence observed in field data. Four key dimensionless numbers have been identified—the ratio of dust to saltation flux, the volume fraction of dust in the bed, a size ratio of dust to saltators in the bed, and the ratio of the friction velocity above threshold to the threshold friction velocity. Traditional analyses using only the flux and friction-velocity ratios show little correlation; analyses of these data with the other parameters demonstrate the importance of the particle-size distribution and the inadequacy of simple parameterizations and friction-velocity models.
Studies are being conducted using literature data to validate the new model. In addition, a wind tunnel will be used to conduct experiments to test the model and the importance of the dimensionless parameters. The wind tunnel is being constructed for use in this research project; the experiments will take several years to complete.Supplemental Keywords:
fellowship, dust, particle-size distribution, abrasion, friction, flux, wind tunnel, particles, analytical model, resuspended dust, contaminant transport, risk assessment.