INDOOR RADON MEASUREMENTS FOR THE SOUTH AFRICAN WEST COAST PENINSULA.

Granite commonly contains high concentrations of uranium, with consequent high exhalation of radon. The geology of the West Coast peninsula of South Africa is dominated by granite, and a recent article predicted potentially high indoor radon concentrations in this region's two largest towns, Vredenburg and Saldanha. This research aimed to measure indoor radon levels in these towns. Measurements were first done for a minimum of 3 d during warmer months, with houses typically being more ventilated. Thirty-four homes in Vredenburg and 27 in Saldanha were measured, and the average indoor radon determined to be 40 and 58 Bq m-3, respectively. The measurements were then repeated during the colder months, and an increase in average radon concentration of 173 Bq m-3 for Saldanha and 153 Bq m-3 for Vredenburg was found. The granite geology and lifestyle of occupants during the colder months seem to contribute towards elevated levels of indoor radon concentrations.