Carcinogenic risk coefficients at environmental levels of radon exposures: a microdosimetric approach

We report a microdosimetric-based evaluation of the effects of domestic exposure to radon. The risk coefficients obtained here are based on the microdosimetry of radon progeny alpha particles, on a function q(y) for in vivo radiogenic neoplasia, and on scaling A-bomb results (epidemiology + microdosimetry) to radon exposure. We do not use miner data, nor do we invoke such notions as quality factors, dose equivalent or equivalent dose. With basal cells as targets our estimated risk coefficients are in good agreement with the miner data, and thus a quality factor of about 20 (as suggested by ICRP 60) is not unreasonable. However, if we take as targets the secretory cells our risk coefficients are twice as large as those reported by BEIR-IV. The main uncertainty in these estimates remains the dosimetric model.