Method for Predicting the Occurrence of Small Radon

Radon prone houses are often associated with uranium-rich geologic formations, but these formations are difficult to predict in the absence of indoor radon measurements. Even with data, it may be difficult to specify a hot spot if the area does not conform with established administrative boundaries or if there is uncertainty to the specific test location due to confidentiality. Radon in soil gas and in indoor air has been shown to follow lognormal distributions. If data from a random selection of homes are presented on lognormal graph paper, they will be represented by a straight line. Systematic deviation from the line at high radon concentrations is a sensitive indicator of the presence of a small geologically localized radon hot spot. The graphical procedure for finding a hot spot requires establishing the background distribution. The larger the sample size the more accurately the distribution is characterized in the high-radon tail. Sparsely populated hot spots remain difficult to fmd and the better strategy involves evaluating each geologic province separately.