Effects of residential mobility on individual versus population risk of radon-related lung cancer

Abstract

The U.S. Environmental Protection Agency (EPA) does not consider the effects of normal patterns of residential mobility in estimating individual radon-related lung cancer risks. As a consequence, the EPA's population risk estimates may have little bearing on individual risks, and remediation of high-radon homes may have only small health benefits for the individuals who remediate their homes. Through a simulation analysis, we examine the effects of residential mobility on radon exposure and lung cancer risk. Given normal mobility, only 7% of eventual radon-related mortality among current 30 year olds will occur in the 5% currently living in homes above 4 pCi/l (the EPA's action level for remediation), in contrast with an estimate of 31% of deaths when mobility is ignored. Above 10 pCi/l, the no-mobility assumption implies 10.3% of deaths, compared to only 0.4% when mobility is taken into account. We conclude that knowledge of one's current radon exposure is not necessarily a useful guide to one's risk, especially for residents of the high-radon homes targeted for remediation by the EPA. The risk of such individuals is likely to be substantially lower than that implied in the EPA's risk charts. If people currently living in high-radon homes remediate their houses, the majority of the resulting health benefits will accrue to future occupants of their homes.