Radon risk mapping in Spain: a population and building-inclusive approach

Radon is a major health risk and a leading cause of lung cancer among non-smokers. Traditional radon maps in Spain, such as those from the Consejo de Seguridad Nuclear (CSN), rely primarily on geological data but do not account for building characteristics and population distribution, limiting their accuracy in assessing exposure risks. This study integrates the CSN Radon Potential Map with detailed building data from the Spanish Cadastre to create a more precise radon risk map for Spain. By incorporating factors such as building height, floor levels, and residential distribution, we analyzed over 12 million buildings and 26 million dwellings across 7,978 municipalities. The results revealed significant deviations from the CSN Radon Potential Map, particularly in densely populated areas, where structural characteristics influenced risk assessment. Our approach led to the reclassification of 4,927 municipalities (61.75%), demonstrating the importance of including built environment data in radon risk evaluation. The findings highlight the need for a more comprehensive mapping approach that considers actual population exposure rather than solely geological potential. While this integrated map improves risk assessment and can inform public health strategies, direct radon measurements remain essential for precise evaluations. Further research is needed to refine this methodology and enhance its applicability in radon mitigation efforts in line with European directives.