Comparisons of indoor radon to other radiation hazards

The significance of radon as a cause of cancer can be put into perspective by a comparison with other causes of cancer. Lung cancer is fatal in about 90% of the cases and therefore in assessing radon exposures it is pertinent to make a comparison in terms of mortality figures. There is a broad range of estimates for the U.S. lung cancer mortality from indoor radon, extending from well below 5,000 to above 20,000 per year. For simplicity in making comparisons, the authors use an intermediate estimate of 10,000 per year, although one needs to bear in mind this number is uncertain. Given approximately 480,000 fatal cancers in the United States per year and 136,000 fatal lung cancers, this estimate corresponds to indoor radon being responsible for 2% of all cancer mortality and 7% of lung cancer mortality. It is estimated that 83% of lung cancers are due to smoking, corresponding to about 113,000 deaths per year. Overall, therefore, smoking is far more important than indoor radon as a cause of lung cancer. Despite the authors' concentration on it, radon is a relatively small contributor in the perspective of cancer as a whole or even of lung cancer alone. It is a more dominant contributor in considering average exposures to ionizing radiation