The significance of ICRP, BEIR and UNSCEAR to the radon exposure in Belgium

BEIR VI replaced in 1998 the BEIR VI report of 1988 increasing the lung cancer risk estimates with 20 to 75 % depending on the selected risk model. ICRP derived in 1993 (publication 65) a risk of 0.00028 per WLM from the BEIR VI estimate for a "world" population with a somewhat lower cancer mortality, resulting in a dose conversion convention for indoor radon exposure of 2.4 nSv. ICRP published in 1994 a new dosimetric model of the respiratory tract (publication 66). NRPB applied this model to indoor radon and found a wide distribution with a central estimate of 9.4 nSv. Both the epideiological and dosimetric (lung model) approaches result in higher values than the ICRP 65 dose conversion convention. This was the main motive for the UNSCEAR committee to keep the value of the UNSCEAR 1993 report of 9 nSv, or 9 x 0.4 = 3.6 nSv (radon exposure). The average radon exposure in Belgium according to the UNSCEAR 2000 report is therefore 1.2 mSv/year.