Indoor radon concentrations in European kindergartens and other educational facilities

Radon and its progeny threaten the health of children, a vulnerable group. However, researchers have focused on children's exposure to radon in residential buildings. This literature review synthesizes existing research to comprehensively examine radon levels in European kindergartens and other educational facilities. We review common measurement methods, collate radon concentrations, identify contributing factors, offer mitigation strategies and recommend systematic strategies for evaluating radon in these environments. Our literature review included 26 search terms employed in combination to identify relevant publications from 2014 to 2024 stored in electronic databases. Exploring relevant reference lists extended the breadth of our source collection, ensuring that we used a wide range of sources to facilitate rigorous analysis. When measured by tracking α radiation activity, radon concentrations vary with the temporal measurement method employed. Our study revealed median radon concentrations between 10 and 1,478 Bq/m³ with active sampling and between 6 and 360 Bq/m³ with passive sampling. Notably, 5 % of studies exceeded the European limit of 300 Bq/m³, while 56 % surpassed the World Health Organizations' (WHO's) recommended limit of 100 Bq/m³. One concerning finding was that the maximum radon levels in 79 % of the studies exceeded 300 Bq/m³. Kindergartens displayed higher radon concentrations than schools did. Measures such as regular assessments and harmonised measurement methods are therefore crucial, particularly when energy efficiency measures are involved. We strongly recommend reducing national radon reference values to the WHO- endorsed level of 100 Bq/m³ and applying consistent radon monitoring and evaluation strategies in all education facilities, particularly those with suspected elevated radon contamination.