In-situ measurement of radon and thoron exhalation rates from interior walls in a Japanese building

Sakoda, Akihiro   ; Ishimori, Yuu ; Hasan, Md. M.*; Jin, Q.*; Kanzaki, Norie   ; Iimoto, Takeshi*

Building materials such as brick and concrete are known to be one of indoor radon (Rn-222) and thoron (Rn-220) sources. Most radon and thoron exhalation studies have been based on laboratory tests using pieces and blocks of such materials. To elucidate how laboratory findings can be used in a real-world environment, we conducted intensive in-situ radon and thoron exhalation tests on interior walls, with different structure types of an apartment (i.e., solid wall and cavity wall) for over a year. This study provides an insight into parameterizing a radon source input in modeling the spatial and temporal dynamics of indoor radon and thoron air concentrations.