• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.469-480
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• 2004

The radon concentrations were measured to survey distribution of radon concentrations in Seoul subway stations. The radon concentrations in air and water were measured at seventeen subway stations(Mapo, Chungjongno, Sodaemun, Kwanghwamun, Chongno3ga, Ulchiro4ga, Tangdaemun, Sangildong on Line 5;Nowon, Chunggye, Hagye, Kongnung, Taenung, Mokkol, Chunghwa, Sangbong, Myomok on Line 7) using the $RAdtrak^{TM}$ radon gas detector, Pylon AB-5 continuous passive radon detector and liquid scintillation counting method from January to May 1999. The major results obtained from this study were as follows: The long-term mean concentrations of radon were $61.8\;Bq/m^3$ in office, $78.9\;Bq/m^3$ in platform, $38.2\;Bq/m^3$ in concourse and $20.1\;Bq/m^3$ in outdoor, respectively. These levels were less than the action level ($148\;Bq/m^3$) of the U.S. EPA. The highest level of short-term mean concentrations was $116.55\;Bq/m^3$ at Chongno3ga station on the 5th line subway stations, while the lowest mean concentration was $19.55\;Bq/m^3$ at Mokkol station on the 7th line subway stations. The highest concentration of radon in the road water and storing underground water in the subway stations was $234.7\;KBq/m^3\;and\;155.5\;KBq/m^3$ in Sodaemun subway station, respectively. The results suggest that radon concentration in subway stations seems to be affected by ventilation and radon concentratin in underground water in the subway stations.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.2
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• pp.176-184
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• 2019

Objective: This study aims to characterize airborne radon and thoron levels ($Bq/m^3$) generated from working environments in three subway stations in Seoul. Method: A radon and thoron detector (EQF3220) was used to monitor real-time airborne radon and thoron levels ($Bq/m^3$) and their daughters ($Bq/m^3$) every two hours. They were monitored not only in the driver's cabin of seven circulation lines, but also three offices, platforms, and water pump reservoirs in the three stations. Results: The average levels of radon and thoron were $67.9Bq/m^3$ (range; $7.2-619.4Bq/m^3$) and $44.4Bq/m^3$ (range; $4.3-819.2Bq/m^3$), respectively. Notably, higher than legal airborne radon levels ($600Bq/m^3$) were frequently monitored in the driver's cabin of seven circulation lines. Airborne radon levels monitored in the platforms and administrative offices were found to be over $100Bq/m^3$. The average equilibrium factors (F) were 0.12 and 0.06, respectively. The percentages detected were found to be 84.9 for radon and 72.4 for thoron, respectively. Conclusions: Significant airborne radon and thoron levels were frequently found to be generated in subway facilities including water reservoirs, platforms and driver's cabins. Further study is necessary to thoroughly investigate airborne radon and thoron in all subway stations and to devise proper measures.

• Journal of radiological science and technology
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• v.29 no.2
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• pp.53-56
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• 2006

The purpose of the present study is to find ways to reduce the quantity of indoor radon contamination. The study was done from July, 2005 until December, 2005. It was found out that the easiest and most effective way to do that is to open the windows as often as possible and let the indoor air flow outside. When it is not possible to ventilate a room, the indoor radon contamination quantity can reduced by providing activated charcoal in the room. It has been proved that activated charcoal can absorb the room in the air. We need more activated charcoal in proportion to the size of the room. A further research is needed to investigate the amount of activated charcoal that will work most effectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.120-121
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• 2018

Radon is one of the substances that pollute the indoor air and is classified as a first-level carcinogen by the International Agency for Research on Cancer(IARC) together with asbestos, and it is reported that it can cause lung cancer. The World Health Organization(WHO) reports that lung cancer is the second leading cause of lung cancer, and 6-15% of lung cancer patients report lung cancer caused by radon. Radon occurs in cracks in concrete and aged buildings, and is detected in soil, rocks, groundwater, and so on. It is a colorless, odorless and tasteless gas which is adsorbed to dust in the air and enters through human respiratory system. This study used vermiculite (expanded vermiculite), which has excellent ion exchange ability and a large number of pores, and industrial by - product red mud which has heavy metal adsorption ability, in order to adsorb radon. A matrix capable of adsorbing radon was prepared, and the characteristics of each material were compared and analyzed.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.59-67
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• 2012

Platform screen doors (PSD) installed at 289 stations in Seoul metropolitan subway from November 2005 to December 2009, are expected to prevent death from a fall and improve air quality. In this study, we systematically surveyed changes in radon concentrations before and after PSD installation in Seoul metropolitan subway stations. By solid-state nuclear track detectors (SSNTD), the radon concentrations before and after the PSD installation were measured at 54 stations of 6 lines from 2 to 7 reported to have relatively high radon concentrations. Mean radon concentrations at platforms were decreased by approximately 56% from 121.7 Bq/$m^3$ to 54.0 Bq/$m^3$. Before PSD installation, mean radon concentrations were in the decreasing order for subway lines 7, 5, 6, 3, 4 and 2. On the other hand, after PSD installation the order was changed to 5, 6, 7, 3, 4 and 2. According to a radon map of Seoul metropolitan subway, the number of platforms where radon concentration over was 74 Bq/$m^3$ decreased from 38 to 12 after PSD installation.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.539-550
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• 2008

Lung cancer is the most prevalent global cancer, ${\sim}90%$ of which is caused by cigarette smoking. The LNT hypothesis has been inappropriately applied to estimate lung cancer risk due to ionizing radiation. A threshold of ${\sim}1\;Gy$ for lung cancer has been observed in never smokers. Lung cancer risk among nuclear workers, radiologists and diagnostically exposed patients was typically reduced by ${\sim}40%$ following exposure to <100 mSv low LET radiation. The consistency and magnitude of reduced lung cancer in nuclear workers and occurrence of reduced lung cancer in exposed non-worker populations could not be explained by the HWE. Ecologic studies of indoor radon showed highly significant reductions in lung cancer risk. A similar reduction in lung cancer was seen in a recent well designed case-control study of indoor radon, indicating that exposure to radon at the EPA action level is associated with a decrease of ${\sim}60%$ in lung cancer. A cumulative whole-body dose of ${\sim}1\;Gy$ gamma rays is associated with a marked decrease in smoking-induced lung cancer in plutonium workers. Low dose, low LET radiation appears to increase apoptosis mediated removal of $\alpha$-particle and cigarette smoke transformed pulmonary cells before they can develop into lung cancer.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.2
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• pp.9-17
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• 2020

The ratio of the deterioration housing in rural area was 29.6%, but it was 18.3% in urban area based on a 2018 survey. In consideration of the point, this study aims to analyze the actual condition of indoor air quality in rural houses to provide basic data for improving the indoor air environment. It was investigated 15housings of Hongseong-gun, Chungchengnam-do. To investigate the correlation between indoor air quality and housing type, both the field survey of housing type and precision diagnosis of concentration of indoor air pollutants such as HCHO, TVOC, Fine dust(PM-10, PM-2.5), CO₂, Radon. The results of this study are as follows. First, according to the average value of each element of rural old housing, the construction year was distributed in 1939~2004, and 12households(80%) living in houses older than 30years have passed for about 46years. As for the housing area, more than 12houses(80%) of 60㎡ or more and 3 houses (20%) of less than 60㎡ were often living in relatively small-scale housing. Second, as a result of measuring indoor air pollutants in rural houses, substances exceeding the standard values were found in HCHO, TVOC, CO₂. Third, in the case of Fine dust and Radon, none of such factors were exceeded the standard. Fourth, there was no significant difference in indoor air quality depending on housing type in rural houses. This paper is expected to contribute to the regional development projects and effective implementation of rural policies.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.313-318
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• 2020

Since radon is an inert gas and is a monoatomic molecule, the size of one particle represents the size of an atom, which means that it has a radius of approximately 1 to 100 nm. Therefore, if the mask has a radius smaller than the size of general fine dust and ultra fine dust, but it is possible to block the inhalation of radon more than a certain amount, it is considered that the exposure through the inhalation of radon can be reduced through normal indoor wear. Accordingly, we would like to find out the radon blocking effect of a mask worn in everyday life. Looking at the reduction rate of radon for each mask, cotton masks decreased by 33.45%, medical masks by 33.50%, KF 80 masks by 35.12%, and KF 94 masks by 37.72%. It was found that the radon blocking effect of the cotton and medical masks was somewhat inferior to that of the KF mask, but the difference was not so great that the introduction of radon into the air could be blocked to a certain level by wearing a mask.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.80-81
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• 2017

The study conducted a thermal conductivity test of magnesium oxide to manufacture boards using absorbent to produce board of radon gas molecules that are absorbed into the indoor air pollutants, which are currently in question, among other indoor air pollutants. Using material are the vermiculite and anthracite, in case of the vermiculite, which results in large porosity due to the expansion, in case of the anthracite, which characteristic generates pore on the matrix. As a result of the experiment, the lowest value was given to 0.6161 kcal/mh℃ which adding vermiculite 10% and anthracite 40%. However, adding vermiculite 40% and anthracite 10%, slightly higher 0.7229 kcal/mh℃, it is deemed the anthracite has more porosity than the vermiculite and, it judged that pore occurrence during the mixing process, appeared that the heat conductivity go down.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.38-45
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• 2017

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is $3.7Bq/m^3$. Also, long-term data were measured by using ${\alpha}-track$ radon detectors(${\alpha}-track$, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of $7.4Bq/m^3$. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged $20.6{\pm}17.0Bq/m^3$($3.7-115.8Bq/m^3$) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using ${\alpha}-track$ in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of $1,000Bq/m^3$ for workplaces and also below the lower USEPA residential guideline of $148Bq/m^3$. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 mSv/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers' exposure.