“…In the viewpoint of public health protection, many surveys measuring indoor and outdoor radon gas have been conducted for dwellings in many countries (Chung et al, 1998;Xiaoyan, 2006;Font et al, 2008;Yu et al, 1996a, b;Espinosa et al, 2008;Liendo et al, 1997). Kim et al (2003) also reported the nationwide survey results of indoor radon concentration of dwellings in South Korea for the period of 2000, there are few studies regarding radon survey in underground public facilities, especially in Korea, such as subway or underground stations, underground shopping malls and underground parking facilities (Jeon, 2007).…”