Correlations for Predicting Air Permeabilities and 222Rn Diffusion Coefficients of Soils

Abstract

The rate of ²²²Rn gas transport through earthen materials controls ²²²Rn releases to the atmosphere and to indoor environments. The key soil-related parameters characterizing ²²²Rn transport in earthen materials are the ²²²Rn diffusion coefficient and the soil air permeability. Simple correlations have been developed for predicting the ²²²Rn diffusion coefficient and the air permeability of soils based on fraction of water saturation, total porosity, and arithmetic mean particle diameter. Correlations are based on 1,073 diffusion coefficient measurements and 137 soil air permeability measurements. The geometric standard deviations between the correlation predictions and the measurements are 1.98 for the diffusion coefficients and 2.31 for the soil air permeabilities.