Estimation of the radon concentrations in children's educational institutions of Kropyvnytskyi city for radon protective actions

Abstract

Objective: We studied the levels of radon in the indoor air in pre-school and school educational institutions of Kropyvnytskyi city, Kirovograd oblast for further effective anti-radon measures Materials and methods: We studied equal equilibrium concentration (EEC) of 222Rn in the indoor air of children's educational institutions. Measurements of indoor EEC of 222Rn were carried out with the help of passive track radonometry method using nitrate-cellulose film LR-115 as a detector in heating season. The time of exposure of radon accumulators was not less than 30 days. The chemical treatment of the detectors was performed in the alkali solution NaOH (2.5 M). Calculation of tracks was carried out with the help of spark counter АИСТ. Results: Studies were carried out in the children's educational institutions of Kropyvnytskyi city, Kirovograd oblast. The range of indoor EEC of 222Rn was established to be 12 Bq•m-3 to 332 Bq•m-3, the arithmetical mean was 85 Bq•m-3, the geometrical mean was 69 Bq•m-3 at a standard deviation of 59 Bq•m-3. The levels of 222Rn exceeded the standard level for children’s institutions (50 Bq•m-3) in 64 % of examined premises, excess of the standard was greater by 4-6 fold in 8 premises there. Indoor EEC of 222Rn in the premises, located on the ground floor, was nearly twice as much than in the premises located above the ground floor. Anti-radon measures should be realized in all buildings where the hygienic levels are exceeded. Optimum protective measures are established separately for each definite premise or building and are based on the analysis and assessment of the structural characteristics of the building and the ways of radon intake into it. Effectiveness of performed protective measures is determined by the repeated measurements of radon levels in the same premises.