Thorough investigation of radon in a school with elevated levels

Among the 890 schools surveyed for radon levels in Slovenia, 24 buildings w ere found in which air concentrations exceeded 1000 Bq m(-3) in classrooms. These schools have been thoroughly investigated to find the source of elev ated radon concentration and to undertake measures for the most effective r emediation. The highest radon concentrations, up to 7 kBq m(-3) in classroo ms, were found in a poorly constructed school situated in a karstic area. T he annual effective doses received by staff (3 persons) and pupils (21 pers ons) were estimated to range from 3.7 to 6.7 mSv, according to ICRP 65 meth odology. Their homes were also tested for radon, where annual effective dos es received from radon decay products range from 1.3 to 12.6 mSv. On averag e, the school contributed 60% to the annual effective dose. (C) 2001 Elsevi er Science Ltd. All rights reserved.