Recent epidemiological studies of the association between
lung cancer and exposure to
radon and its decay products are reviewed. Particular emphasis is given to pooled case-control studies of residential exposures, and to cohorts of underground miners exposed to relatively low levels of
radon. The residential and miner epidemiological studies provide consistent estimates of the risk of
lung cancer, with significant associations observed at average annual concentrations of approximately 200 Bq/m³ and cumulative occupational levels of approximately 50 working level months (WLM), respectively. Based on recent results from combined analyses of epidemiological studies of miners, a lifetime excess absolute risk of 5 × 10⁻⁴ per WLM [14 × 10⁻⁵ per (mJh/m³)] should now be used as the nominal probability coefficient for
radon- and
radon-progeny-induced
lung cancer, replacing the previous Publication 65 (ICRP, 1993) value of 2.8 × 10⁻⁴ per WLM [8 × 10⁻⁵ per (mJh/m³)]. Current knowledge of
radon-associated risks for organs other than the lungs does not justify the selection of a detriment coefficient different from the fatality coefficient for
radon-induced
lung cancer. Publication 65 (ICRP, 2003) recommended that doses from
radon and its progeny should be calculated using a dose conversion convention based on epidemiological data. It is now concluded that
radon and its progeny should be treated in the same way as other
radionuclides within the ICRP system of protection; that is, doses from
radon and its progeny should be calculated using ICRP biokinetic and dosimetric models. ICRP will provide dose coefficients per unit exposure to
radon and its progeny for different reference conditions of domestic and occupational exposure, with specified equilibrium factors and
aerosol characteristics.