2020 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215769/ Kojo, Katja Europe Exposure Study Radon Radon Surveillance School Daycare center Indoor radon measurements were performed in 633 daycare centers where the mean radon concentration was 86 Bq/m3 and the median 40 Bq/m3. The radon level was greater than 300 Bq/m3 in 8% (n = 49) of daycare centers. The radon measurements were performed in 1176 schools, which is 95% of the schools to be measured. The mean radon concentration was 82 Bq/m3 and the median 41 Bq/m3. The radon levels were greater than 300 Bq/m3 in 14% (n =169) of the schools.