Indoor Radon Concentrations in Kindergartens from Different Regions of Yugoslavia

Abstract

In the winter period of 1990–1991 instantaneous radon concentrations in air were measured in around 450 kindergartens from different regions from Yugoslavia. Alpha scintillation counting was used as a screening method, and the measurements, were carried out in the rooms where the children spent the majority of their time. All of the air grab samples were taken under the same conditions which excluded ventilation of the interior 12 hours prior to sampling. In addition to indoor radon concentrations, gamma dose rate was measured using portable equipment. The indoor radon concentrations were generally low, in the range from 10 to 180 Bq.m-3 of air, with an overall average of about 100 Bq.m-3. There were a few exceptions where indoor radon levels exceeded 150 Bq.m-3, mainly in old buildings containing higher contents of natural radionuclides in the building materials, and in the cellars or basements of the buildings. In all rooms with a level exceeding 150 Bq of 222Rn per m3, solid-state nuclear track detectors were applied for long-term measurements. In order to investigate the equilibrium between radon and its short-lived daughters, mainly with respect to their contribution to the effective dose, alpha spectrometry is also being introduced in selected kindergartens with elevated radon concentrations.