Radon risk assessment and mitigation deadlines

Abstract

Background: Radon is a radioactive natural gas that is the leading cause of death from lung cancer in non-smokers. It is responsible for the highest share of the yearly effective doses a person is exposed to, and, in many cases, it is the most important indoor pollutant. National regulations on radon typically use derived reference levels, except for occupationally exposed workers that are monitored using a graded approach (e.g. in Switzerland and EU). However, in some countries, radon concentrations in dwellings or workplaces are high and the effective doses are comparable, and even greater than those measured in occupational workplaces. The times spent in different places and the presence of children or disabled people (that usually spend more time indoor) bring a need for assessing the risks of indoor radon exposure using a graded approach for both dwellings and workplaces. It is essential to highlight that the Covid-19 pandemic made more people work from home, and this new situation may be permanent for some workers.
 Objective and Design: On this basis, the objectives of this work are to demonstrate the importance of adequate monitoring of natural radioactivity, simulate effective doses due to radon with the new effective dose coefficients (EDCs) proposed by International Commission on Radiological Protection (ICRP) (publication 137), show case studies that illustrate the need for effective dose calculation and propose a method to set radon mitigation deadlines for buildings with high radon activity concentrations. Moreover, this work will shed light in the question about the possible need for new radon reference levels after the new EDCs were proposed.
 Conclusions: One important outcome of this work is the application of the dose approach in a case study conducted in a dwelling, the measurements and calculations show high annual effective doses (up to 350 mSv/year).