Speaker
Description
Since people spend more than 80% of their daily lives indoors, exposure to natural radiation in indoor environments can have a serious impact on human health and lead to global public health issues. Indoor radiation exposure levels are influenced by building materials and construction methods, as well as the geological characteristics of the bedrock and soil on which the building is constructed. Most building materials of terrestrial origin contain trace amounts of naturally occurring radioactive materials (NORM), consisting primarily of daughter nuclides produced from the decay chains of 226Ra, 232Th, and 40K. These three naturally occurring radionuclides emit gamma rays and cause external radiation exposure to the human body. Internal radiation exposure, on the other hand, is caused by radon (222Rn) and its short-lived decay products (214Bi, 214Pb, and 218Po), which are released from building materials into indoor air. Radon is a daughter nuclide produced by the alpha decay of radium, which is contained in building materials.
This study investigated the radioactivity concentrations of 40K, 226Ra, and 232Th in bedrock samples collected from various geological regions in Korea. Radioactivity concentrations in soil, which has long been widely used in traditional Korean architecture, were also measured. Furthermore, radon exhalation coefficients were investigated for these rocks and soils. Natural radioactivity and radon exhalation coefficients were measured simultaneously using gamma-ray spectroscopy, a relatively simple radioactivity measurement method.
The activity concentration of NORM in rocks and soil, as well as the radon exhalation coefficient, were found to be significantly influenced by the type and origin of the rocks and soil. The average radioactivity concentrations in the rocks were approximately 40 Bq/kg for 226Ra, 80 Bq/kg for 232Th, and 900 Bq/kg for 40K. The average radioactivity concentration in soils were approximately 45 Bq/kg for 226Ra, 100 Bq/kg for 232Th, and 830 Bq/kg for 40K. The average radon exhalation coefficient in rocks and soils was approximately 8% and 25%, respectively.