Laboratory investigation of the relationship between soil surface radon exhalation rate and temperature under...

Radon in soil is a major source of indoor radon, and its surface exhalation rate is controlled by several environmental factors, among which temperature plays a critical role. To investigate the influence of soil surface temperature on radon exhalation under controlled laboratory conditions. A soil simulation device was used to conduct continuous measurements of radon concentration in an accumulation chamber. Before concentration equilibrium was reached, the radon exhalation rate was obtained by fitting a physical exhalation model to the temporal concentration data. After equilibrium, a calculating radon exhalation rate based on real-Time radon concentration model was employed to calculate the temperature-dependent radon exhalation rate. The experiments were divided into two stages: a cooling stage and a heating stage. During the cooling stage, the temperature decreased from 30 °C to 15.5 °C, and the Pearson correlation coefficient between temperature and radon exhalation rate was -0.667. During the heating stage, the temperature increased from 11.3 °C to 24.4 °C, with a correlation coefficient of -0.955. The results reveal a significant negative correlation between soil surface temperature and radon exhalation rate. Overall, the study demonstrates that lower soil surface temperatures enhance radon release, providing clearer evidence for the temperature dependence of soil radon behavior and offering meaningful implications for radon risk assessment and environmental monitoring.