Identification of sources of high radon levels in Slovenian schools

The sources of radon were investigated in twenty selected schools with high room levels of radiation. A combination of radon measuring techniques was applied: etched track and electret detectors to obtain average indoor air radon concentration. devices to record radon concentration continuously and thus characterise its diurnal variation, and alpha scintillation cells to analyse air from potential sources of radon entry. In some cases, a single strong source was identified (e.g. sinks, sub-floor channels), while in others the poor quality of the basic concrete slab was responsible for high indoor radon concentrations. The combination of etched track and electret detectors and alpha scintillation cells was essential for locating these sources.