Abstract
In most countries, radon is the largest natural source of exposure to ionizing radiation for the general population. Numerous case-control studies have been conducted using passive radon (Rn-222) detectors. Recently it has become aware that the reading of passive radon detectors that do not employ thoron (Rn-220) discrimination techniques are affected by thoron. Therefore, we conducted a simulation study to evaluate the possible effect of thoron on radon-related lung cancer risk. The results showed that thoron interference in radon measurement resulted in an approximately 90% downward bias in radon-related lung cancer risk. The standard error of the lung cancer risk estimates tended to be smaller when radon was measured
without thoron discrimination than when radon was measured with thoron discrimination, indicating the error in the radon measurement due to thoron interference resulted in an apparent smaller uncertainty in risk estimates.
