The reduction of indoor radon concentration by using lightweight concrete in high-rise buildings

The radon exhalation rates from surfaces of different types of lightweight concrete used in the building industry in Hong Kong have been studied using standardised activated charcoal canisters and γ spectroscopy. It is found that all the lightweight concretes investigated have considerably smaller radon exhalation rates than those from ordinary concrete. Considering a concrete room of a typical size for Hong Kong, the possible reduction in the indoor radon concentrations has been calculated to be greater than 15 Bq.m^-3 when lightweight concrete is used instead of ordinary concrete for the non-construction walls. The average indoor radon concentration in Hong Kong is about 45 Bq.m^-3. Therefore, a simple and economical way to reduce the indoor radon concentrations and the corresponding radiation dose from radon has been demonstrated. This technique applies to future buildings.