Lung cancer risk at low doses of alpha particles

A theoretical estimate of the hazard of lung cancer induction from inhaled radon daughters and from the combined effects of radon and thoron daughters which takes cell killing into account as competitive with malingnant transformation leads to the evaluation of a risk factor which is a quadratic function of the dose of alpha particles at low doses. It is supported by the results of epidemiological surveys in high background regions in China, Austria, and Finland. In China the total number of deaths from lung cancer in the high background area is less than the excess number of deaths estimated from published risk factors, linearly extrapolated to environmental dose levels. The Chinese data further suggest that other factors than inhaled radon daughters contribute to the higher lung cancer incidence in other countries