Effect modification of ambient particle mortality by radon: A time series analysis in 108 U.S. cities
Numerous studies have reported a positive association between ambient fine particles and daily mortality, but little is known about the particle properties or environmental factors that may contribute to these effects. This study assessed potential modification of radon on PM2.5 (particulate matter with an aerodynamic diameter <2.5 ?m)-associated daily mortality in 108 U.S. cities using a two-stag