Prediction of Environmental Exposures from Sources near the Ground Based on Hanford Experimental Data

Abstract

Values of peak exposure and standard deviations of exposure distributions downwind from a continuous point source are presented for 46 Hanford ground source diffusion experiments. Exposure data are found to order in terms of atmospheric stability when plotted as a function of the travel time. The crosswind variances of the exposure distributions are expressed in terms of the travel time and the product of the standard deviation of the wind direction distribution and the mean wind speed, σ??, in an equation resulting from G. I. Taylor's work in 1921. Prediction methods developed from these concepts permit extrapolation of the results obtained from short releases to much longer release periods. Good agreement between predicted and observed exposure distributions is obtained from these models, using independent data.