This study was performed to determine the effects of soil and building materials on indoor radon concentration. Short-term measurements were made in the underground soil of a building along with the radon emanation rates from the phosphogypsum board used as the interior wall. The radon measurements in the soil were 9,213 Bq/m3 in the B3 level, and 3,765 Bq/m3 in the B4 level. Soil radon concentration in the B4 level was 2.4 times higher than in the B3 level. Indoor radon measurements in 50 different locations in the underground of the building, averaged from 144.3 Bq/m3 (B1), 177.0 Bq/m3 (B2), and 189.2 Bq/m3 (B3) to a high of 210.1 Bq/m3 (B4). Indoor radon concentration was increased from the lower level to the upper level. The radon emanation rates from phosphogypsum were 4,234.1 mBq/m2/h and, 450.4 mBq/kg/h. The measurement results indicated that the phosphogypsum board used as building materials as well as the soil could affect the indoor radon concentration.

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.

The objective of this study is to censure the provision of correct information to the public through investigating radon emanation by building materials that are used in domestic construction environment. Radon emanation has been identified in 10 framing materials and 16 finishing materials of 26 building materials used in the domestic construction-industry. Radon emanation was measured using the closed chamber method based on CR-39 nuclear track detectors(NTDs). On Brick-General in framing materials, the highest radon emanation rates were 0.60028 Bq/ m2·h for surface and 0.00733 Bq/kg·h for mass, while on Ceiling-Tex Cement Plaster in finishing materials. The highest radon emanation rates were 0.47708 Bq/m2·h for surface and 0.05885 Bq/kg·h for mass.

Radon is an inert gas, and a naturally occurring radioactive material. Radon is produced by radium and uranium. Generated radon causes lung cancer through the inhalation. Therefore, If uranium contaminated soil is close to indoor spaces, residents may be exposed to this radioactive material(Radon). Generally, radon affects the first to third floors of buildings. But our research team has often detected high radon concentration in the indoor air of high-rise apartments. The reason for this is that building materials containing uranium and radium are brought into apartments. This study was conducted an investigation into the radon emission rate of building materials being used in South Korea. Also, our team conducted an investigation into the radon emission rate of gypsum tiles and concrete found in an apartment(17th floor apartment indoor radon concentration 5.03 pCi/L, Rad- 7(DURRIDGECo.USA)). Finally, we investigated the radon emission rate of bricks containing the soil near a uranium mine. The average radon emission rates of general building materials are as followings: (gypsum board : 0.20·h-1/kg, gravel : 0.05, gypsum tile : 0.02, indoor tile : 0.08, general brick : 0.02, red clay tile : 0.02, concrete : 0.11, uranium mine soil : 4.81). The results regarding the radon emission rate from a 17th floor apartment’s building materials are as followings: (gypsum board : 0.70, concrete : N/A). The results regarding the radon emission rate from bricks containing soil near a uranium mine was 0.19. This experiment indicates that gypsum boards show the highest radon emission rate among general building materials. In particular, the radon emission rate from the gypsum boards in a 17th floor apartment was 3.5 times higher than general gypsum boards. Overall the results suggest that building materials that possess high levels of uranium emit more radon gas than any other materials. South Korea has not established legal regulations on radon emission from building materials. However, the results of this study strongly suggest that it is of the utmost importance to manage the radon emission rate of building materials and control their usage before construction.

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.