• The Journal of Engineering Geology
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• v.10 no.2
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• pp.189-214
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• 2000

Three study areas of Kwanak campus(Seoul National University), Gapyung and Boeun were selected and classified according to bedrock types in order to investigate soil-gas radon concentrations. Several soil-gas samples showed relatively high radon concentrations in the residual soils which derived from granite bedrock. It also showed that water content of soil and the degree of radioactivity disequilibrium was a secondary factor governing radon emanation and distribution of radon radioactivity. The results of radon concentrations and working levels for forty rooms in Kwanak campus, Seoul National University, showed that indoor basement rooms under poor ventilation condition can be classified as high radon risk zone having more than EPA guideline(4 pCi/L). Some results of section analysis which was surveyed in the fault zone of Kyungju and Gapyung area confirmed the existence of fault-associated radon anomalies with a meaning of radon risk zone.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.333-351
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• 2017

Objectives: This study examines the relationships between indoor radon concentrations and distribution from soil geological mapping in the Hwacheon and Jangsu areas. Methods: GIS and a pivot table were used for inquiries about indoor radon contents, soil characteristics, and geological differences. Results: The Hwacheon area was characterized by the presence of normal and reverse faults as a passage of runoff for radon, sufficient occurrences of minerals containing uranium within granite as a radon source, a high concentration of radon within the granite area and clear differences of radon concentrations between granitic and metamorphic areas. The Jangsu area was characterized by the presence of normal faults, wide distributions of alluvium, and ambiguities on radon concentrations indoors among areas of geological differences. Considering the granite area and alluvium surrounded with granite areas, the characteristics of radon concentrations within soils and indoors in the Jangsu area are similar to those of the Hwacheon area. High concentrations are found with entisol and inceptisol in the Hawcheon area, but with entisol, inceptisol, and ultisol in the Jangsu area. High radon concentrations are found in sandy loam and/or loam. High concentrations are found in recently constructed or brick buildings, but low concentrations in traditional or prefabricated houses showing a high possibility of outward flow. Conclusions: The overall results suggest that radon concentrations in the Hwacheon and Jangsu area are dominantly influenced by geological characteristics with additional artificial influences.

• Journal of Environmental Health Sciences
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• v.45 no.6
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• pp.658-667
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• 2019

Objective: This study was designed to compare construction types and seasonal radon concentrations in dwellings in Jeollabuk-do Province in Korea. Methods: The measurement of indoor radon concentrations in 79 dwellings using alpha-track detectors was performed every three months (seasonally) over one year between 2015 and 2016. Also, Radon concentrations in soil were measured in spring to investigate the correlations between the concentrations in soil and indoor air. Results: The annual average concentration of indoor radon for dwellings was 89.7±72.1(GM: 72.4) Bq/㎥, with a range (min-max) of 17.2 to 505.4 Bq/㎥. The highest indoor radon concentration was measured in winter and the lowest was shown in summer. The geometric mean of radon concentration in winter was 1.03-2.58 times higher than other seasons. Radon concentrations in soil were investigated at the depth of 1 m, and the concentrations ranged from 1,780 Bq/㎥ to 123,264 Bq/㎥. This showed low correlations with indoor radon concentrations.

• Journal of radiological science and technology
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• v.46 no.2
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• pp.141-149
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• 2023

The Korea Institute of Radiological and Medical Sciences plans to produce ²²⁵Ac, a therapeutic radio-pharmaceutical for precision oncology, such as prostate cancer. Radon, a radioactive gas, is generated by radium, the target material for producing ²²⁵Ac. The radon concentration is expected to be about 2000 Bq·m^-3. High-concentration radon-generating facilities must meet radioactive isotope emission standards by lowering the radon concentration. However, most existing studies concerning radon removal using activated carbon filters measured radon levels at concentrations lower than 1000 Bq·m^-3. This study measured ²²²Rn removal of coconut-based activated carbon filter under a high radon concentration of about 2000 Bq·m^-3. The ²²²Rn removal efficiency of activated carbon impregnated with triethylenediamine was also measured. As a result, the ²²²Rn removal amount of the activated carbon filter showed sufficient removal efficiency in a ²²²Rn concentration environment of about 2000 Bq·m^-3. In addition, despite an expectation of low radon reduction efficiency of Triethylenediamine-impregnated activated carbon, it was difficult to confirm a significant difference in the results. Therefore, it is considered that activated carbon can be used as a radioisotope exhaust filter regardless of whether or not Triethylenediamine is impregnated. The results of this study are expected to be used as primary data when building an air purification system for radiation safety management in facilities with radon concentrations of about 2000 Bq·m^-3.

• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.283-292
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• 2007

Atmospheric concentrations of radon had been continuously observed in Seoul, Korea since December 1999, as a tracer for long-range transport of air pollutants from China continent to Korea. In order to study radon as a tracer of long-range transport, it is important to know information about the atmospheric distribution and variation of radon concentration and its time variation. Atmospheric radon concentration are measured with electrostatic radon monitor(ERM) at Hanyang University located in Eastern area of Seoul. Air sample is taken into a vessel of ERM, and alpha particles emitted by radon daughters $Po^{218}$ are detected with ZnS(Ag) scintillation counter. Hourly mean concentrations and hourly alpha counts are recorded automatically. The major results obtained from time series observation of atmospheric radon were as follows : (1) The mean of airborne radon concentration in Seoul was found to be $7.62{\pm}4.11\;Bq/m^3$ during December $1999{\sim}January$ 2002. (2) The hourly variation of radon concentrations showed the highest in 8:00AM ($8.66{\pm}4.22\;Bq/m^3$) and the lowest in 3:00AM ($6.62{\pm}3.70\;Bq/m^3$) and 5:00AM ($6.62{\pm}3.39\;Bq/m^3$). (3) the seasonal variation of radon concentrations showed higher during winter-to-fall and lower during summer-to-spring. (4) Correlation between airborne radon concentration and the meteorological factors were -0.21 for temperature, 0.09 for humidity, -0.20 for wind speed, and 0.04 for pressure. (5) The mean difference of airborne radon concentration between Asian dust ($5.36{\pm}1.28\;Bq/m^3$) and non-Asian dust ($4.95{\pm}1.49\;Bq/m^3$) phenomenon was significant (p=0.08). We could identify time series distribution of radon concentration related meteorological factors. In addition, radon can be considered a good natural tracer of vertical dispersion and long-range transport.

• 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.

• Journal of Environmental Health Sciences
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• v.40 no.6
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• pp.484-491
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• 2014

Objectives: A radon emission reducing agent was prepared using charcoal and zeolite, and the amount was measured after coating construction materials with the agent. The availability of the radon emission reducing agent was evaluated. Methods: Construction materials (red brick, cement brick, and gypsum board) coated with reducing agent were placed in a chamber to measure radon emissions. The construction materials were coated one through three times. The spread volume for brick and gypsum board was 50 mL and 75 mL per application, respectively. The amount of radon emitted was measured by RAD-7 after 48 hours. Results: The reduction ratio increased with the number of coatings, and the reduction ratios for red brick, cement brick, and gypsum board were 63.3, 73.6, and 58%, respectively, in the case of three coatings of RA-1. The reduction ratios for red brick, cement brick, and gypsum board were 42.8, 58.1, and 26.2%, respectively in the case of three coatings with RA-2. RA-1 was slightly better than RA-2 in radon emission reduction. Conclusions: Radon emissions from construction materials decreased according to the concentration of reducing agent coating, and it was more effective than existing methods.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.27-28
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• 2019

Recently, a bed company detected a radon more than Red Politics and became a hot topic of conversation. This has led to increased interest in radon, and a number of free-of-charge bodies have also been established to recognize the dangers of radon. In addition, the Korean Institute of Geological and Resource Research is planning to assist the installation of radon alarm systems in 10,000 households nationwide, free of charge. Since radon is a colorless, odorless and tasteless gas that causes lung cancer, it aims to reduce lung cancer incidence by absorbing radon using bamboo activated carbon as a way to reduce it. Due to the use of bamboo activated carbon, radon concentration per hour tends to decrease as substitution rate increases, and table flow tends to decrease as substitution rate increases. Through this experiment, 30% of the replacement rate of bamboo activated carbon is judged to be the most suitable replacement rate.

• 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 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.