47. 通过矿井空气中的氡浓度来推算家中的氡浓度为评估住宅受到氡辐射后产生的风险提供了一个间接基础。不过，现在已就住宅氡和癌症开展了 20 多项分析性研究。这些研究一般根据诊断患有肺癌之前 25 至 30 年期间的住宅照射估计数对氡照射产生的相对风险进行评估。近期对住宅案例控制研究进行的汇总分析表明，住宅照射存在较小但可以查出的肺癌风险，这种风险随着照射量的增加而增加。对浓度为 100 Bq m-3 的长期住宅氡照射所产生的超高相对风险的确定具有较高的精确度，据认为，这一风险约为 0.16%（对照射评估中的不确定性加以更正之后），高于或低于这个数值的不确定性系数约为 3 倍。由于氡照射的影响和吸入香烟烟雾的影响之间的协同增效作用，吸烟者占住宅氡照射人口平均风险的近 90%。
47. The extrapolation of radon concentrations in the air in mines to those in homes provides an indirect basis for assessing the risks from residential exposure to radon. However, there have now been over 20 analytical studies of residential radon and lung cancer. These studies typically assess the relative risk from exposure to radon on the basis of estimates of residential exposure over a period of 25 to 30 years prior to diagnosis of lung cancer. Recent pooled analyses of residential case control studies support a small but detectable lung cancer risk from residential exposure and this risk increases with increasing exposure. The excess relative risk from long-term residential exposure to radon at 100 Bq m-3 is established with reasonably good precision and is considered to be about 0.16 per cent (after correction for uncertainties in exposure assessment) with about a three-fold factor of uncertainty higher or lower than that value. Because of the synergistic interaction between the effects of radon exposure and those of inhalation of tobacco smoke, smokers account for nearly 90 per cent of the population-averaged risk from residential exposure to radon.