Indoor radon monitoring through citizen science in Catalan schools: environmental assessment and educational outcomes

Introduction Indoor radon represents a significant environmental health hazard because high indoor radon concentration exposure increases lung cancer risk. Schools are critical settings due to prolonged occupancy by children. The RASCLET citizen-science project (Catalonia, Spain) integrated school-based radon monitoring with educational activities to evaluate exposure conditions and examine whether these activities increased radon knowledge and risk awareness. Meteorological variables and modeled radon flux were also explored in relation to indoor radon variability. Methods Integrated radon measurements were conducted in 13 schools across Catalonia (Spain) during the winter of 2024–2025. Detectors were placed in classrooms on different floors. Schools represented different radon risk areas defined by official Spanish radon potential maps. At each school, approximately 40 students participated in educational activities about radon under their teacher’s supervision. Students and their teacher then selected the classrooms where detectors would be installed. Pre and post-intervention questionnaires assessed changes in students’ knowledge and perceptions of radon risks. Results Indoor radon concentrations varied across schools and floor levels, with a median concentration of 49 Bq m −3 (interquartile range: 24–77 Bq m −3 ). All measurements obtained during the winter monitoring period remained below the 300 Bq m −3 reference level. PRE and POST-intervention questionnaires were completed by 538 and 339 students, respectively. The mean age was 11.07 ± 1.18 years (PRE) and 10.99 ± 1.04 years (POST), with female-to-male distributions of 49.4%/46.8 and 48.7%/48.7%, respectively. Correct identification of radon as a radioactive gas increased from 34.2 to 72.9% and recognition of its long-term health effects increased from 42.0 to 85.5% (both p < 0.001). Additionally, indoor radon data, combined with meteorological and radon flux data, were used in an exploratory modelling analysis. The analysis identified wind speed as the only statistically significant environmental variable associated with observed indoor radon concentrations ( p = 0.025). Conclusion These findings indicate that integrating school-based radon monitoring with citizen-science and educational activities can support exposure assessment, strengthen environmental health literacy, and improve radon risk communication in educational settings. This pilot study also provides a rationale for designing and conducting a larger-scale study across Spain to further evaluate this integrated approach.