A summary of UNSCEAR 2019 report on lung cancer from exposure to radon and research needs

The annex B of the UNSCEAR 2019 Report presented a comprehensive review of dosimetric and epidemiological assessments published in the period 2006 to 2017 for deriving conversion factors for calculating the dose from a given exposure to radon (²²²Rn). The conversion factor is needed for comparison purposes with other sources of radiation exposure. Even though extensive research has been conducted, uncertainties remain large. Given that the uncertainties from both dosimetric and epidemiological studies give rise to a broad range of risk estimates and the fact that values from the current dosimetry and epidemiological reviews are consistent with those used in previous UNSCEAR reports, the Committee recommends the continued use of the dose conversion factor of 9 nSv⋅ ​(h⋅Bq⋅m⁻³)⁻¹ equilibrium equivalent concentration of ²²²Rn for estimating radon exposure levels to a population. This paper summarizes the findings of UNSCEAR's scientific evaluations and its decision regarding the dose conversion factor for population exposure to radon. Research needs for better assessing doses to the lung and risks of lung cancer from exposure to radon are also discussed.