House Characteristics Associated with Gamma Radiation and Radon Daughter Working Levels in Eastern Pennsylvania

Working levels (WL) of radon daughters and ..gamma.. measurements in basements are described for approx.1200 houses near the Reading Prong. House variables studied included condition and construction materials of basement floors and walls, basement heights and areas, heating systems, air conditioning, water supply, and presence of drains and sump pumps. WL's were poorly predicted by house characteristics or ..gamma.. measurements, while ..gamma.. levels were well predicted by house characteristics and WL. Except for windowless basements, associated with both high ..gamma.. andl high WL measurements, factors predicting high ..gamma.. levels tended to be associated with low WL's and vice versa. Dirt basement floors and fieldstone basement walls were strongly associated with high ..gamma.. levels, as were poor wall conditions in multivariate analyses. Gamma levels were low in electrically heated homes. High WL's were strongly associated with electric heat, low WL's with basement walls of fieldstone and/or in poor condition. Large house volumes and well water supply were also associated with higher WL's. 4 refs., 1 fig., 4 tabs.