Influence of energy-saving measures on the radon concentration in some kindergartens in the Czech Republic.

Due to the large number of subsidies for energy-saving reconstructions granted, and expecting a strong influence of reconstruction on the radon level in building, the long-term measurements of radon concentration are offered free of charge to kindergartens in the Czech Republic. Classrooms and playrooms where the radon levels exceeded the reference value for kindergartens, which is 400 Bq m(-3), are monitored continuously for at least a week to obtain the average activity concentration of radon when children are present. Some of the kindergartens were previously measured in the 1990s. These earlier measurements have provided an opportunity to compare the results. This paper presents some lessons learned from radon diagnosis carried out in particular cases and an analysis of the influence of reconstruction work on the radon level in the buildings.