“…Recently, high 220 Rn concentrations have been reported in areas with granites (Vinay Kumar Reddy et al, 2003;Luo et al, 2005), in earth buildings , and in adobe and brick houses in China (Qiuju et al, 2005). Wide surveys on thoron level have been carried out (Doi et al, 1994;Yonehara et al, 2005;Dwivedi et al, 2005;Sreenath Reddy et al, 2004;Bochicchio et al, 1996;Ramola et al, 2005;Espinosa et al, 2005;Celestina, 2005;Tokonami et al, 2004;Sugino et al, 2005). However, there are still a few data on 220 Rn concentration in dwellings of Korea.…”