Radon, a naturally occurring radioactive gas formed from uranium decay, is a significant health hazard and the leading cause of lung cancer among the general population. Radon gas can infiltrate building structures through cracks and openings in the building envelope. The concentration inside the building is influenced by factors such as indoor temperature, humidity, and ventilation rates.

This study focuses on a case study house in Victoria, BC, Canada, where radon measurements were taken over a six-week period during the heating season to capture real-world indoor radon behaviour. A combination of real-world data collection, analytical calculations, and computational fluid dynamics (CFD) simulations was used to analyze radon concentration patterns under varying temperature, humidity, and ventilation conditions. The CFD model was developed using ANSYS Fluent, with the indoor environment simulated under different temperatures (18°C, 21°C, and 24°C) and humidity (20%, 40%, and 60%) conditions at an air change rate of 0.5 ACH (air change per hour) from the field experiment.

Numerical and experimental (field) observations revealed that indoor temperature significantly influences radon concentration, with higher temperatures enhancing the stack effect, leading to increased radon levels. Numerical simulations showed that humidity also played a critical role, where higher humidity levels acted as a barrier to radon infiltration, reducing its accumulation. The study validated the CFD model by comparing it with measured field data and analytical results, demonstrating less than a 2% difference, confirming its reliability.

This research contributes valuable insights into indoor radon concentration and behaviour, emphasizing the importance of maintaining optimal indoor environmental conditions to manage radon exposure. The findings highlight the need for integrated radon mitigation strategies, considering temperature, humidity, and ventilation to ensure safer indoor air quality in residential buildings in Victoria, BC, Canada. These insights can inform building design, public health policies, and radon management practices, helping to reduce radon-related health risks.