Evaluation and measurement methods for the surface radon exhalation rate of buildings

Half of the natural radiation dose to the human body comes from indoor radon and its progeny, inhaling of which plays a key role in the development of lung cancer. Given the relationship between the radon exhalation rate (RnER) and the indoor radon concentration, accurate determination and control of the former directly affect the control and protection of the latter. In this study, a method was developed to estimate the actual RnER of building walls through building material samples. The surface RnER of the wall of any thickness that was constructed of any building material could be calculated by its intrinsic RnER value and radon diffusion length, which could be obtained by measuring the RnER of the pre-treated building material sample models through the activated carbon box-γ spectroscopic method. The experimental results indicated that the deviation between the calculated wall surface RnER of the building and the measured wall surface RnER of the building was <5.1%. Therefore, the intrinsic RnER of building materials could be regarded as an evaluation index for the RnER of buildings.