With increasing public awareness regarding radon, this study has been conducted with the aim of providing more accurate information about radon to the public. We investigated the radon emissions from gypsum boards, which are known to emit relatively higher levels of radon among the building materials available on the market. Radon emissions were measured over three weeks using the closed chamber method with nuclear track detectors. For ceiling materials, the arithmetic mean of the radon emissions was 43.8 ± 42.2 Bq/m3 (geometric mean: 28.9 ± 5.6), 156.2 ± 150.5 mBq/m2/h per unit area (geometric mean, 103.1 ± 2.7) and 21.1 ± 19.9 mBq/kg/h per unit mass (geometric mean: 14.4 ± 2.6). Regarding the wall materials, the arithmetic mean of radon emissions was 24.1 ± 24.0 Bq/m3 (geometric mean: 15.6 ± 2.6), 133.3 ± 143.4 mBq/m2/h per unit area (geometric mean, 76.8 ± 3.0) and 13.0 ± 10.4 mBq/kg/h per unit mass (geometric mean, 9.5 ± 2.3). According to the results of this study, higher radon concentrations and emissions were detected in the ceiling materials than in the wall materials, but these values were lower than those previously measured in building materials.

Developing proper reduction strategies of indoor radon which have been an important issue in Korea requires proper information on source characteristics a phosphate gypsum board which is a common building material used for inter-wall thermal protection in Korea could be a major source of indoor radon level. This study evaluated the correlation between indoor radon concentration and the attribution of gypsum board content in building materials. In this study we valuated indoor/outdoor radon from 58 facilities selected based on the information availability of gypsum content in the building material across 8 different cities in Korea. Our results showed that indoor radon concentrations were 2 to 3 times higher than outdoor but those results were not significantly attributed from gypsum contents in the building material. Indeed, phosphate content in gypsum board did not significantly play a role in indoor radon level variations. It is concluded that physical environmental condition such as temperature, relative humidity, radon exhalation rate out of each building materials, as well as pathway from external sources (e.g., soil) needs to be identified to develop indoor radon reduction strategies.