Nationwide Distribution of Indoor Radon

A rapidly growing United States data base consisting of over 90,000 indoor radon concentrations measured with passive integrating Track Etch detectors is described. The data base is subdivided by region and state, and a variety of s t a t i s t i c a l parameters summarizing the contents of the data base are presented for each geographical area. The primary conclusions that can be drawn are that there are some homes with unacceptably high radon levels in nearly every s t a t e , and that there exist regions where a significant fract ion of homes have unacceptably high radon levels. I n i t i a l attempts t o make the data base more representative of the United States a s a whole indicate an arithmetic mean fo r the couutry of between 3 and 4 pCi11.