Measurements of radon in residential buildings in Maryland and Pennsylvania, U.S.A

Radon concentrations were measured in six all-electric and 31 randomly selected homes in Pennslyvania, and 41 homes in Maryland. The measurements were made in the basements and living areas of each home using integrating passive activated carbon detectors for an exposure period of about 3 days. The average concentration varied substantially among the homes and correlated well with the age of the home, the degree of insulation, and ventilation. On average, concentrations in the living areas were lower than those in the basements. Radon levels in the living areas of a substantial number of homes (39% in Pennslyvania, excluding the six all-electric homes, and 51% in Maryland) were greater than or equal to 3 pCi.1-1, resulting in a substantial annual absorbed dose to the bronchial epithelial cells of the occupants of the homes. (author)