• Journal of Environmental Science International
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• v.24 no.9
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• pp.1131-1138
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• 2015

Radon exhalation rates have been determined for samples of concrete, gypsum board, marble, and tile among building materials that are used in domestic construction environment. Radon emanation was measured using the closed chamber method based on CR-39 nuclear track detectors. The radon concentrations in apartments of 100 households in Seoul, Busan and Gyeonggi Provinces were measured to verify the prediction model of indoor radon concentration. The results obtained by the four samples showed the largest radon exhalation rate of $0.34314Bq/m^2{\cdot}h$ for sample concrete. The radon concentration contribution to indoor radon in the house due to exhalation from the concrete was $31.006{\pm}7.529Bq/m^3$. The difference between the prediction concentration and actual measured concentration was believed to be due to the uncertainty resulting from the model implementation.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.668-674
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• 2019

Objectives: Modern people spend most of their day indoors. As the health impact of radon becomes an issue, public interest also has been growing. The primary route of potential human exposure to radon is inhalation. Long-term exposure to high levels of radon increases the risk of developing lung cancer. Radon exposure is known to be the second-leading cause of lung cancer, following tobacco smoke. This study measures the indoor radon concentrations in detached houses in area A of Chungcheongbuk-do Province considering the construction year, cracks in the houses, the location of installed detectors, and seasonal effects. Methods: The survey was conducted from September 2017 to April 2018 on 1,872 private households located in selected areas in northern Chungcheongbuk-do Province to figure out the year of building construction and the location of detector installed and identify the factors which affect radon concentrations in the air within the building. Radon was measured using a manual alpha track detector (Raduet, Hungary) with a sampling period of longer than 90 days. Results: Indoor radon concentrations in winter within area A was surveyed to be 168.3±193.3 Bq/㎥. There was more than a 2.3 times difference between buildings built before 1979 and those built after 2010. The concentration reached 195.4±221.9 Bq/㎥ for buildings with fractures and 167.2±192.4 Bq/㎥ for buildings without fractures. It was found that detectors installed in household areas with windows exhibited a lower concentration than those installed in concealed spaces. Conclusion: High concentrations of indoor radon were shown when there was a crack in the house. Also, ventilation seems to significantly affect radon concentrations because when the location of the detector in the installed site was near windows compared to an enclosed area, radon concentration variation increased. Therefore, it is considered that radon concentration is lower in summer because natural ventilation occurs more often than in winter.

• Journal of Environmental Health Sciences
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• v.42 no.5
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• pp.345-351
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• 2016

Objectives: The objective of this study was to conduct risk assessment using indoor radon concentration and exposure times. Methods: The target facilities were military facilities before and after the application of radon reduction processes and underground commercial facilities in major subway stations in Seoul. Indoor radon concentrations were measured by passive sampler. Results: Radon concentrations in 13 military facilities were initially higher than the guidelines, but the levels were below guidelines after the application of radon reduction processes. Underground shopping mall radon concentrations near subway stations in Seoul satisfied the guidelines. However, indoor radon effective doses after radon reduction processes in some military facilities and those in underground shopping malls belonged to International Commission on Radiological Protection (ICRP) groups needing control management. Conclusion: Indoor radon management requires risk assessment data that takes into account working time (or residence time) in addition to management according to concentration guidelines.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.325-332
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• 2014

Growing concerns about harmful influence of radon on human body, many efforts are being made to decrease indoor radon concentration in advanced countries. To develop an indoor radon reduction technology, it is necessary to develop a technology to predict and evaluate indoor inflow and emission of radon. In line with that, the present study performed computational modelling of indoor dispersion of radon emitted from building materials. The computational model was validated by comparing computational results with analytical results. This study employed CFD (Computational Fluid Dynamics) analysis to evaluate the radon concentration and the airflow characteristics. Air change rate and ventilation condition were changed and several building materials having different radon emission characteristics were considered. From the results, the indoor radon concentration was high at flow recirculation zones and inversely proportional to the air change rate. For the different building materials, the indoor radon concentration was found to be highest in cement bricks, followed by eco-carats and plaster boards in the order. The findings from this study will be used as a method for selecting building materials and predicting and evaluating the amount of indoor radon in order to reduce indoor radon.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1123-1130
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• 2018

Purpose: Exposure to indoor radon is associated with lung cancer. This study aimed to estimate the number of lung cancer deaths attributable to indoor radon exposure, its burden of disease, and the effects of radon mitigation in Korea in 2010. Materials and Methods: Lung cancer deaths due to indoor radon exposure were estimated using exposure-response relations reported in previous studies. Years of life lost (YLLs) were calculated to quantify disease burden in relation to premature deaths. Mitigation effects were examined under scenarios in which all homes with indoor radon concentrations above a specified level were remediated below the level. Results: The estimated number of lung cancer deaths attributable to indoor radon exposure ranged from 1946 to 3863, accounting for 12.5-24.7% of 15623 total lung cancer deaths in 2010. YLLs due to premature deaths were estimated at 43140-101855 years (90-212 years per 100000 population). If all homes with radon levels above $148Bq/m^3$ are effectively remediated, 502-732 lung cancer deaths and 10972-18479 YLLs could be prevented. Conclusion: These findings suggest that indoor radon exposure contributes considerably to lung cancer, and that reducing indoor radon concentration would be helpful for decreasing the disease burden from lung cancer deaths.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.71-76
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• 2002

A survey of radon concentrations in both indoor and outdoor atmospheres was carried out using EIRM and Cup Monitor for the period of February 1996 to March 1997. EIRM were used to measure the indoor and outdoor radon concentration at five major cities university. Cup Monitor were also used to measure the indoor radon concentrations at shopping store, office building, apartment, hospital and house in Seoul. The mean indoor and outdoor radon concentrations at the five major cities(Seoul, Daegu, Daejon, Cwangiu and Busan) were 24.1 Bq/m$^3$and 8.62 Bq/m$^3$, respectively. The ratio of indoor to outdoor radon concentrations ranged front 1.7 to 3.9. Inspection of its seasonal distribute pattern indicates the enhancement during winter relative to summer, consistently for both indoor and outdoor air. The results of the survey showed that the concentrations in basements were clearly higher than those in usual living/working places.

• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.264-275
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• 2007

The objective of this study was to offer basic and scientific data for decision-making of policy for improvement and management of radon, natural radiation gas, in Korea and to form the foundation of radon related international cooperation. Therefore, this study collected and re-analysed the articles on exposure of radon in various indoor environment in journals related environment in Korea since 1980 and estimated the annual exposure dose and effective dose by exposure of radon received by inhabitants in them. The highest pooled average radon concentration of $50.17{\pm}4.08\;Bq/m^3$ (95% CI : $42.17{\sim}58.17\;Bq/m^3$) was found in dwelling house among various indoor environment. All of pooled average radon concentration estimated in this study showed lower than the guideline concentration ($148\;Bq/m^3)$ of US EPA and the Korean Ministry of Environment. The annual effective dose received by inhabitants in various indoor environment was estimated 1.071 mSv/yr. That is equal to annual effective dose (1.0 mSv/yr) by exposure of radon estimated by UNSCEAR.

• Journal of the Korea Furniture Society
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• v.22 no.1
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• pp.13-17
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• 2011

Recently, interest in indoor air quality is increasing. Especially, radon radioactivity among the indoor air is a well-known risk factor for lung cancer because of ionizing radiation in the form of ${\alpha}$-particles. This study was carried out to investigate effect of black charcoal and activated carbon for reduction of radon radiation that emitted from building materials. Black charcoal and activated carbon were used as a barrier which was against the infiltration of radon. The source of radon was gypsum board. Two types of charcoal barrier were powder- and board-type with 5 mm, 10 mm thickness respectively. The method for this determination is evaluated radon concentration in chamber. The measurements were performed with radon detector, SARAD3120. Results of this study are as following: Black charcoal and activated carbon confirmed the highly efficient barrier. Radon concentration was reduced from 72% to 85% as compared the control chamber. Radon reduction capability, however, was no difference as barrier's types. Results obtained in ventilation condition, radon concentration shows 5.93 pCi/L on average in the closed condition and shows 2.69 pCi/L in the opened condition.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.588-595
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• 2006

Indoor radon($^{222}Rn$) concentrations of subway stations in Seoul area were measured to survey the environmental indoor radon levels and to identify sources of radon. The radon concentration of indoor air by method of long-term measuring with a-track detector were surveyed at 232 subway stations from 1998 to 2004. And the radon concentration in ground-water was measured with a method of alpha particle counting. To trace main source of radon, 8 out of 232 stations were selected and their radon concentrations in tunnel and on platform were analyzed. Total geometric mean and arithmetic mean of radon concentrations in all stations from 1998 to 2004 were $1.40{\pm}1.94pCi/L,\;1.65{\pm}1.07$ respectively. Geometric means of radon concentrations on platform and concourse were $1.54{\pm}1.96pCi/L,\;1.23{\pm}1.88pCi/L$ respectively, with higher concentration at the platform than at the concourse. The geological structure was significantly correlated to the indoor radon concentration in subway stations region. Radon concentrations of adjacent tunnel and ground-water of subway station was significantly correlated to the indoor radon concentration in subway stations. And There was a significant difference in radon concentration, depending on the depth levels in platform of subway stations(p<0.05).

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.4
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• pp.24-31
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• 2019

In this paper, we simulated a new apartment building by using radon emission test values from various building materials used as interior finishing materials. The simulations evaluated the radon concentration in the room according to the radon emissions and the ventilations for each type of finishing material (gypsum board, stone, tile and concrete). Overall concrete finish simulation case showed the highest concentration than the case using other materials due to the effect of wall area at the center of each room and the mean radon concentration at 1.5 m above the floor was slightly lower than the mean value at each center. In the case of the porch, pantry and bathroom, the radon concentration was high even when the same materials were used as in the other rooms.