Indoor radon measurements in the New York Capital District.

Radon-222 concentrations have been measured in 21 "energy-efficient" homes and 14 conventional homes in the New York Capital District. Usual concentrations are averaged over six-month or 12-month periods using solid-state track detectors. Full-year averages are available for 23 of the homes, and the winter-to-summer variations have been observed. In a number of cases, 222Rn emanations from various construction materials and soil samples have been measured and correlations sought with indoor 222Rn. Two major patterns emerge. The living areas of the energy-efficient homes without heat-storage masses have median radon concentrations that are 1.6 times those for conventional homes, and the energy-efficient homes with heat-storage masses have four to five times the 222Rn of conventional homes.