Observational study of the scavenging of radon daughters by precipitation from the atmosphere

Abstract Radon daughter concentrations in precipitation and in surface air have been observed since 1977 in Maizuru, Japan, in order to study the relationship between the two concentrations and the influence of precipitation patterns on the concentration in precipitation. Results obtained from analysis of the observed data suggest that radon daughters in precipitation originate mainly from scavenging within the cloud (rainout) and not from that below the cloud (washout).