Radon in indoor air of primary schools: a systematic survey to evaluate factors affecting radon concentration levels and their variability

Abstract

In order to optimize the design of a national survey aimed to evaluate radon exposure of children in schools in Serbia, a pilot study was carried out in all the 334 primary schools of 13 municipalities of Southern Serbia. Based on data from passive measurements, rooms with annual radon concentration GT 300Bq/m(3) were found in 5% of schools. The mean annual radon concentration weighted with the number of pupils is 73Bq/m(3), 39% lower than the unweighted 119Bq/m(3) average concentration. The actual average concentration when children are in classrooms could be substantially lower. Variability between schools (CV=65%), between floors (CV=24%) and between rooms at the same floor (CV=21%) was analyzed. The impact of school location, floor, and room usage on radon concentration was also assessed (with similar results) by univariate and multivariate analyses. On average, radon concentration in schools within towns is a factor of 0.60 lower than in villages and at higher floors is a factor of 0.68 lower than ground floor. Results can be useful for other countries with similar soil and building characteristics.