Climate change exacerbates residential radon exposure and lung cancer risk

Climate change adaptation strategies, such as increased air conditioning use, greater time spent indoors, and seeking cooler lower-floor spaces, may inadvertently increase residential radon exposure and associated lung cancer risk. We conducted a scoping review of literature on climate change and indoor radon, then developed four exposure scenarios reflecting plausible behavioral shifts: current conditions, increased air conditioning use, increased time in basements, and a combined scenario. Using the BEIR VI exposure-age-concentration model, we estimated cumulative excess risk of lung cancer mortality by age 85 for US and pooled French-German-Italian populations. Compared to current conditions, the combined hypothetical scenario yielded an additional 46 lung cancer deaths per 10,000 persons in the US, and 42 in Europe. These findings highlight an unrecognized pathway through which climate change adaptation may amplify population-level cancer risk, if available countermeasures are not taken.