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Description
Between years 2015 and 2026 several indoor radon surveys in selected Slovak kindergartens were realized using passive track detectors with three months exposure. In total 61 kindergartens were monitored, in 37 of them one-year long survey was conducted and in 27 kindergartens also continuous monitoring was performed, at least during one three-month exposure of passive detectors. Annual average indoor radon ranged in wide interval, from 50 to almost 2000 Bq/m3. Since the overall risk from radon is several times greater for children than for adults, the primary goal was to determine the radiation dose from radon for children during their stay in kindergarten. However, continuous measurements proved a significant overestimation of average radon activity concentration determined using passive track detectors, therefore the next goal was to make a correction only for the duration of children's stay in kindergartens, based on adding continuous radon measurements. A significant factor influencing radon activity in kindergartens was the use of the working space, especially ventilation. The effect of ventilation was evident in all seasons. On the contrary, closing of kindergartens for weekends or during holidays (summer, Christmas, flu season) caused an increase and saturation of indoor radon in kindergarten classrooms. Two kindergartens were found, where corrected effective doses for children reached up to 6 mSv per year. Without this correction, the effective doses based on the results obtained using track detectors were exceeding 10 mSv per year. The effort was also to determine the seasonal correction factors for kindergartens and apply them in kindergartens in which radon survey was not carried out throughout the year. Due to the different type of using the workplace, the seasonal correction factors determined for houses cannot be used for kindergartens.
Acknowledgements
This work was supported by the Slovak Research and Development Agency (project No. APVV-21-0356).