Search for radon sources in buildings--kindergartens

In ten high radon level kindergartens, radon sources were sought by applying a combination of several radon measuring techniques: etched track detectors to obtain average indoor air radon concentration, continuous devices to record radon concentration and see its diurnal variation, and alpha scintillation cells to determine radon concentration in the air entering a room from cracks, holes and sinks in the floor and from under-floor channels. In three cases, a strong local radon source was identified while, in the others, the bad quality of the basic concrete slab was responsible for the high indoor radon concentration.