• Particle and aerosol research
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• v.13 no.2
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• pp.87-95
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• 2017

Radon ($Rn^{222}$) is a radioactive gas and is found at high concentrations underground. Investigations were done in many years specifically on public transportations such as in the subway stations, concourses and platforms for these are located underground areas. This study correlates the $Rn^{222}$ concentrations with the Particulate Matter (PM) concentration for the gas could be attached or trapped inside these particles. It was done on the opening subway tunnel of Miasageori Station going to Mia Station (Line 4) last August 2016. Based on the result, the $Rn^{222}$ were more influenced on the mass ratio (%) of PM present in the air instead of its mass concentration (${\mu}g/m^3$). As the $PM_{10}$ mass ratio increases ($42.32{\pm}1.03%$) during morning rush-hours, radon starts to increase up to $0.97{\pm}0.03pCi/L$. But during the afternoon $Rn^{222}$ concentrations decreased while the composition were stable at $22.96{\pm}3.0%$, $39.04{\pm}0.6%$ and $38.01{\pm}0.3%$ in $PM_1$, $PM_{2.5}$ and $PM_{10}$ respectively. It was then assumed that it could be the composition of the morning hours of the station were influencing the concentration of the radon.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.3
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• pp.283-291
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• 2018

Objectives: To monitor the radon concentration level in plants that handle phosphorus rock and produce gypsum board and cement, and evaluate the effective dose considering the effect of radon exposure on the human body. Methods: Airborne radon concentrations were measured using alpha-track radon detectors (${\alpha}$-track, Rn-tech Co., Korea) and continuous monitors (Radon Sentinel 1030, Sun Nuclear Co., USA). Radon concentrations in the air were converted to radon doses using the following equation to evaluate the human effects due to radon. H (mSv/yr) = Radon gas concentration x Equilibrium factor x Occupancy factor x Dose conversion factor. The International Commission on Radiological Protection (ICRP) used $8nSv/(Bq{\cdot}hr/m^3)$ as the dose conversion factor in 2010, but raised it by a factor of four to $33nSv/(Bq{\cdot}hr/m^3)$ in 2017. Results: Radon concentrations and effective doses in fertilizer manufacturing process averaged $14.3(2.7)Bq/m^3$ ($2.0-551.3Bq/m^3$), 0.11-0.54 m㏜/yr depending on the advisory authority and recommendation year, respectively. Radon concentrations in the gypsum-board manufacturing process averaged $14.9Bq/m^3$ at material storage, $11.4Bq/m^3$ at burnability, $8.1Bq/m^3$ at mixing, $10.0Bq/m^3$ at forming, $8.9Bq/m^3$ at drying, $14.7Bq/m^3$ at cutting, and $10.5Bq/m^3$ at shipment. It was low because it did not use phosphate gypsum. Radon concentrations and effective doses in the cement manufacturing process were $23.2Bq/m^3$ in the stowage area, $20.2Bq/m^3$ in the hopper, $16.8Bq/m^3$ in the feeder and $11.9Bq/m^3$ in the cement mill, marking 0.12-0.63 m㏜/yr, respectively. Conclusions: Workers handling phosphorous gypsum directly or indirectly can be assessed as exposed to an annual average radon dose of 0.16 to 2.04 mSv or 0.010 to 0.102 WLM (Working Level Month).

• Journal of Environmental Health Sciences
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• v.41 no.2
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• pp.61-70
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• 2015

Objectives: The purpose of this research was to examine radon exposure in terms of the relationship between the living environment and indoor radon concentrations among vulnerable households. Methods: Nationwide, 1,129 subjects were selected using personal questionnaires for adequately understanding the living environment, installation of E-PERM radon gas detectors, and investigation of the structure of the housing. Results: The mean concentration of indoor radon for all subjects was $130.2Bq/m^3$ (GM=101.7), and a total of 438 subjects (38.8%) exceeded the recommended standards ($148Bq/m^3$) for public facilities by the Ministry of the Environment. By location, the highest concentrations ($164.3Bq/m^3$, GM=124.1) were seen in North Chungcheong Province. In the case of the Seoul/Gyeonggi Province metropolitan area, they showed $125.6Bq/m^3$ (GM=105.1) and $118.9Bq/m^3$ (GM=96.5), respectively. By type of housing, indoor radon concentrations in single-family housing were higher than in row/multi-family housing (p<0.01). Although indoor radon concentrations raised in accordance with year of construction (p<0.05), the difference between indoor radon concentrations in underground residences was not observed to be statistically significant (p=0.633). Conclusion: More studies are necessary in the future regarding the difference in indoor radon concentrations that may occur due to different of types of indoor construction, building materials, and the amount of building materials.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.31-36
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• 2013

The radioactive gas radon ($^{222}Rn$), which is generated from the decay process of uranium ($^{238}U$) originating from the soil of more than 85 percent higher the porosity of the soil, the soil can radiate out the possibility that many isotopes. In order to protect the human body from radon, above all, the development of accurate measurement techniques to formulate appropriate measures should be followed. This study Gamma-ray spectrometry using a high purity germanium (HPGe) detector, if you want to measure radon unstable the nature radiation of the background problems can be reduced, radium and radon daughter nuclides after radioactive equilibrium leads to Radon concentration was measured, the soil samples from the Gamma-ray emitting nuclides, and the energy spectrum is analyzed.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.369-375
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• 2023

Radon, a carcinogenic substance generated from soil or building materials, have to be fundamentally blocked from entering indoors. In this study, ethylene vinyl acetate (EVA)/silicone emulsions with excellent mechanical and thermal properties and effective blocking of radon gas were prepared by using radiation technology. As the electron-beam irradiation does increased, a partially crosslinked structure was formed in EVA molecular chain, increasing tensile properties and adhesive strength. The EVA/silicone film showed excellent thermal stability without deformation. In addition, the non-irradiated EVA/silicone film showed a radon blocking rate of about a 75%, while the EVA/silicone film irradiated with 3 and 5 kGy showed an excellent radon blocking rate of over 90% due to the formation of crosslinked structure in the EVA molecular chain. These results indicated that the radiation technology can effectively block radon by forming a partially crosslinked structure of EVA/silicone emulsion to improve tensile property, adhesive strength, and deformation stability.

• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.279-291
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• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.1
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• pp.71-84
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• 2017

Radon, which enters the interior environment from soil, rocks, and groundwater, is a radioactive gas that poses a serious risk to humans. Indoor radon concentrations are measured to investigate the risk of radon gas exposure and reliable radon concentration mapping is then performed for further analysis. In this study, we compared the predictive performance of various univariate kriging algorithms, including ordinary kriging and three nonlinear transform-based kriging algorithms (log-normal, multi-Gaussian, and indicator kriging), for mapping radon concentrations with an asymmetric distribution. To compare and analyze the predictive performance, we carried out jackknife-based validation and analyzed the errors according to the differences in the data intervals and sampling densities. From a case study in South Korea, the overall nonlinear transform-based kriging algorithms showed better predictive performance than ordinary kriging. Among the nonlinear transform-based kriging algorithms, log-normal kriging had the best performance, followed by multi-Gaussian kriging. Ordinary kriging was the best for predicting high values within the spatial pattern. The results from this study are expected to be useful in the selection of kriging algorithms for the spatial prediction of data with an asymmetric distribution.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.230-231
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• 2018

Recently, the danger for radioactive materials has become a hot topic. Beginning with the Chernobyl nuclear accident in 1996, in 2011, the Fukushima nuclear power plant in Japan suffered major damage such as large-scale casualties and radioactive dangerous area selection. Concerns about leakage of radioactive materials due to recent earthquakes have been deepening in Korea, such as Wolsong Nuclear Power Plant in Gyeongju, and there is a growing interest in the safety of radioactive materials through the media and the media. However, the route to exposure to radioactive materials is not limited to these large-scale nuclear accidents. Typical examples of this are radioactive substances exposed in daily life. In the case of radon gas, the danger is being revealed through current events programs and news, and natural radiation exposure is attracting attention.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.1-10
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• 1992

A number of investigators have reported the formation of the radiolytic ultrafine particles produced by the interaction of ionizing radiation with water vapor. Previous studies have suggested that a very high localized concentration of the OH radical produced by the radiolysis of water can react with trace gas like organic vapors and produce lower vapor pressure compounds that can then nucleate. In order to determine water vapor dependence of the active, positively charged, first radon daughter(Po-218), an experiment was conducted using a well-controlled radon chamber. The activity size distribution of the radon daughter in the range of 0.5-100nm was measured using the parallel graded wire screens system. Measurements were taken for different relative humidity. The resultant activity size distributions were analyzed. The addition of water vapor to the radon carrier gases resulted in the formation of ultrafine particles by OH radicals formed by radon radiolysis. It may be due to the neutralization of charged Po-218 ion with water vapor through the radio lysis.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1282-1288
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• 2020

In the first study, the Radon emanation and radiological hazards associated with radionuclides in soil samples, collected from 9 various date palm farms located in 3 different districts in Saudi Arabia were determined through a high purity Germanium (HPGe) gamma-ray spectrometer. The estimated average values of Radon emanation coefficient and Radon mass exhalation rate for soil samples were 0.535 ± 0.016 and 50.063 ± 7.901 mBqkg^-1h^-1, respectively. The annual effective dose of radionuclides in all sampling locations was found to be lower than UNSCEAR's recommended level of 0.07 mSvy^-1 for soil in an outdoor environment. In the secondary study, gross α and gross β activities in soil and date palm pits samples were measured by a low background α/β counting system. Average values of gross α and gross β activities in soil and date palm pits samples were 5.761 ± 0.360 Bqkg^-1, 38.219 ± 8.619 Bqkg^-1 and 0.556 ± 0.142 Bqkg^-1, 24.266 ± 1.711 Bqkg^-1, respectively.