Lung deposition in rodents during exposure to attached radon progeny

Abstract Tumour induction has been studied in rodents exposed to radon and its progeny with potential alpha energy concentrations ranging from 600 to 1800 working levels (WL). As part of these studies, the deposition of short-lived radon progeny ( 218 Po, 214 Pb, and 214 Bi) in the lung has been measured in a sample of exposed animals. Exposure conditions were monitored continuously including individual radon progeny concentrations and the ‘unattached’ fractions of 218 Po and PAEC. Following exposures under similar conditions of aerosol size (0.15 μm count median diameter) and low ‘unattached’ fraction (