Indoor radon concentrations in European school buildings

The radon isotope 222Rn, a well-known carcinogen, is of particular concern in school buildings due to the high risk of exposure. These buildings are heavily occupied, primarily by children, who are especially vulnerable. This study aimed to summarize the indoor radon concentrations in European school buildings. A literature review was conducted using Google Scholar with the search term "radon exposure at schools, Europe" and a publication timeframe spanning 2014 to 2024. To expand the search scope, reference lists from relevant articles were also reviewed. Altogether, 25 publications reporting indoor radon exposure in school buildings were included in the analysis.
Analysis of these studies revealed that the reported median radon concentrations ranged from approximately 20 to 360 Bq/m³. The lowest median concentration was observed in Porto, Portugal, while the highest was recorded in Alba, Romania. Six percent of the studies reported median concentrations exceeding the European regulatory limit of 300 Bq/m³. However, when using the WHO's recommended indoor radon reference level of 100 Bq/m³, this percentage increased to 50%. Additionally, in 85% of the studies, the maximum radon levels surpassed 300 Bq/m³.
Radon levels can vary significantly within school buildings due to factors such as soil geology, ventilation, the use of Heating, Ventilation, and Air Conditioning (HVAC) systems, the building's construction year, structural features like foundation wall materials, classroom floor level, the presence or absence of underground floors, and the number of occupants, including students and teachers. To manage and reduce children's exposure to radon, regular assessments of radon levels in school environments are essential, especially when energy-efficient measures are implemented in the building.