A study of airborne radon levels in Paarl houses (South Africa) and associated source terms, using electret ion chambers and gamma-ray spectrometry

Indoor radon (222Rn) concentrations were measured in Paarl homes by means of electret ion chambers. The concentrations varied between 28 and 465 Bq m−3. The average values (Bq m−3) found in houses on the west and east side of the Berg River, which bisects Paarl, were 132 (±11) and 37 (±3), respectively. Radiometric analyses of soils show that the mean 226Ra activity concentration is three times higher on the west than on the east side of the Berg River.