Simulating the Dispersion Behavior of Indoor Thoron Using Computational Fluid Dynamics (CFD)

Presence of indoor radon and thoron due to exhalation from soil and building materials has become increasingly recognized potential background radiation risk. This study presents the thoron behavior influencing indoor air quality in terms of concentration and distribution using the technique of computational fluid dynamics (CFD) in three dimensions. A model room of volume about 35 m3 was selected and the thoron is studied inside the domain where all walls act as source of thoron by exhalation process. Obtained thoron contours in the room show its inhomogeneous activity distribution. Thoron wall profile is also studied and shows the higher pollutant concentration near source. Results for thoron level and its distribution of the present simulation scenario agreed well with the analytical results. Stagnant zones where the level is higher than average concentration are found in the domain coinciding with corners which are not much influenced by the airflow profile. The study is important for estimation of health risk due to thoron by knowing its exact dispersion and helpful in mitigation strategies.