Similarities and differences between radon surveys across Europe: results from MetroRADON questionnaire

Background: As a major cause of lung cancer after smoking, indoor radon is a hazard for human health. Key steps of radon surveys are numerous and include metrology, survey design, development of maps, communication of results to stakeholders, etc. The Council Directive 2013/59/EURATOM introduced new challenges for European Union Member States, such as the identification of radon priority areas, which calls for efforts to improve all the key steps involved in radon surveys. Objective: This study aims to compare existing radon measurement procedures between different European countries and to use the results to optimize the consistency of indoor radon data across Europe. Design: A questionnaire was developed and sent to more than 70 European institutions working in this field to collect information on indoor radon surveys carried out in the respective countries, in order to identify the rationale and methodologies used. Results: A total of 56 questionnaire forms on indoor radon surveys were completed and returned by universities, research institutions, and competent authorities on national and regional surveys from 24 European countries. The replies have been analyzed, and the main findings have been reported, although these replies did not allow to answer all the questions about comparability. Conclusions: From the replies given by the respondents, there is evidence that European indoor radon surveys are comparable regarding measurement methods but not comparable regarding the survey design. Comparability regarding data management, statistical treatment, aggregation, and mapping is unclear on the basis of the replies putting in evidence the need of further information