What does the new UNSCEAR evaluation tell us about public exposure to radon and thoron worldwide?
The speaker is Wolfgang Ringer (AGES, Austria), former ERA President and member of the Expert Group on Radon and Thoron for the UNSCEAR public exposure evaluation.
Abstract
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) publishes scientific evaluations concerning the exposure of the population to ionizing radiation from natural and artificial sources. Following its 2008 report, UNSCEAR launched an update to incorporate new data and methodological advances for revised global estimates of public exposure. For the new report, the expert group on radon and thoron reviewed and assessed about 2,000 publications as well as data submitted by 61 member states, based on defined quality criteria.
The focus was on the results of national (and regional) surveys of radon and thoron concentrations in buildings and outdoors and radon concentrations in drinking water. Additionally, aspects such as temporal and spatial variability of radon concentrations in buildings, time spent indoors, equilibrium factor for radon, and temporal trends are described in the report.
Based on data from 57 countries (covering 63 % of the world population), the global population-weighted average indoor radon concentration is 50 Bq/m3 , outdoor concentrations averaged 10 Bq/m3, and radon in water showed a median of 10 Bq/L with large variability. The global average annual effective dose from natural sources was estimated at 3.0 mSv. About 60 % (1.8 mSv) results from inhalation of radon, thoron, and their decay products.
This updated UNSCEAR assessment represents a comprehensive global evaluation of public exposure to radon and thoron, highlighting the need for harmonized surveys and standardized measurement protocols to address remaining data gaps. The presentation focusses on the key findings related to radon and thoron.