Although monitoring of radon has been extensively implemented throughout South Korea, the risk assessment has been mainly limited to indoor environments such as schools, workplaces, and multi-use facilities, and evaluations have normally been performed separately. In this study, the differences in radon exposure according to two groups (< 1 and 1-6 years old) were evaluated considering various indoor and outdoor environments, timeactivity patterns, variations in radon concentrations, and dwelling type (single detached and apartment house) using Monte-Carlo simulation. The distribution and representative values of radon concentration by micro-environments were confirmed through the Anders-Darling test, and a uniform distribution was applied in case of uncertainty. The effective dose ranged from 1.81 ± 1.19 to 2.81 ± 3.02mSv/y. Comparing the levels recommended by EPA, WHO, and ICRP with the value of the 95th percentile of this study, it was found that the results for those dwelling in detached houses exceeded recommended levels. Infants that spend a lot of time in homes with relatively high levels of concentration of radon are assessed to be somewhat more vulnerable to radon exposure.

In this study, we learned about the effects of indoor radon concentration reduction associated with the operation of a mechanical ventilation system at an apartment house. The experimental parameters were mainly the indoor radon level and air change rate, which were controlled by the amount of emissions released and fan motor speed. Even at the high level of radon diffused in an apartment house, indoor radon concentrations converged to the Korean national guideline level within 3 to 4 hours when the air was ventilated at 0.5 ACH and 0.7 ACH. In the case of 0.3 ACH, however, where the degree of ventilation was insufficient compared to the legal air change rate, the high concentration indoor radon could not be sufficiently removed even if the mechanical ventilation system was operated for more than 14 hours continuously. When the indoor radon level was high, the reduction rate was 34.3% for 0.3 ACH, 70.4% for 0.5 ACH, and 69.7% for 0.7 ACH at 6 hours-operation, while at the medium-level, indoor radon can be reduced by 46.2% (0.3 ACH) to 73.2% (0.7 ACH). Depending on the indoor concentration range, it may be required to secure a ventilation rate of 0.5 ACH or more at all times. In addition, in apartment houses with excellent airtight performance, even if indoor radon is at a level similar to the national guideline, it is difficult to expect a reduction in the concentration due to natural decay. Therefore, it is desirable to lower the indoor concentrations as much as possible.

This study was designed to verify what effect the use of a natural ventilation system can have on improving indoor air quality with regard to radon in various concentration ranges in an apartment house. The results show that both high (2~3 times higher than 148 m3) and low (similar to 148 Bq/m3) levels of indoor radon concentrations can be reduced close to and/or below the Korean IAQ guideline within 6 hours when the natural ventilation system is operated at approximately an air change rate of 0.5. In the case of an air change rate of 0.3, however, the indoor radon levels cannot meet the national guidelines and the reduction effect was insufficient with regard to various radon concentrations. Typically, the air change rate of a natural ventilation system is affected by meteorological factors such as temperature, relative humidity, wind speed, pressure. Its effectiveness varies according to such factors, for that reason, the reduction effects on radon did not increase proportionally with the ventilation time in this study.

This experiment evaluated the efficiency of mechanical ventilation, one of the measures to reduce indoor radon concentration in residential spaces. In the most popular ventilation rates of the air conditioning system, the most efficient air conditioning system was confirmed by checking the time when the radon concentration reached the lowest level, the radon reduction rate, and the radon concentration that could be lowered as much as possible. The results showed a reduction rate of up to 80% or more as a result of conducting the experiment by blocking the inflow of outside air. It was confirmed that the time to reach the lowest concentration after starting the mechanical ventilation was about 6 hours to a maximum of 7 hours. Therefore, this study verified that indoor radon concentrations can be efficiently reduced by using a mechanical ventilation system.

Radon is a radioactive gas material, which is not detectable by humans because of the absence of color and odor. Radon gas can exist indoors through a number of pathways and long-term exposure to such material can affect the human body, which may result in serious health issues such as lung-cancer. It is thus essential to reduce and maintain indoor radon concentration in order that potential health risks from radon can be diminished. In order to achieve the aforementioned goals, it is requisite to utilize a practical detector which is capable of continuous radon monitoring. In relation to this, a recently developed prototype radon detector, i.e., RS9A, provides highperformance comparable to existing research-grade radon detectors for the purpose of continuous radon monitoring in the air. Furthermore, RS9A is a convenient piece of equipment for use by the public as it is compact in size and affordable. In this paper, we conducted continuous measurements of indoor radon concentrations by using sets of RS9A and evaluated the equivalence of RS9A in terms of quality assurance.

Radon is known to be one of the representative carcinogen materials, and may cause severe health damage to the human body with long-term exposure. Without proper treatment such as natural and mechanical ventilation, indoor radon concentration tends to increase as time passes. In this aspect, it is necessary to maintain indoor radon concentration below the domestic indoor air quality (IAQ) management standard by continuous monitoring. However, the number of practical devices which can detect radon concentration is scarce and most of the existing devices are very costly. Among such devices, the RS9A, a prototype of a radon detector, detects indoor radon concentration and is priced significantly lower compared to other existing radon detectors. In this paper, we investigated the RS9A for the continuous detection of indoor radon gas and compared its performance to a commercially available radon detector (RadonEye). We measured indoor radon concentrations at two separate sites by using both detectors simultaneously. The indoor radon concentrations measured by the aforementioned detectors revealed a high correlation. Therefore, the RS9A can be considered as an appropriate candidate for use as a continuous indoor radon monitoring system.

This study was performed to determine the effects of soil and building materials on indoor radon concentration. Short-term measurements were made in the underground soil of a building along with the radon emanation rates from the phosphogypsum board used as the interior wall. The radon measurements in the soil were 9,213 Bq/m3 in the B3 level, and 3,765 Bq/m3 in the B4 level. Soil radon concentration in the B4 level was 2.4 times higher than in the B3 level. Indoor radon measurements in 50 different locations in the underground of the building, averaged from 144.3 Bq/m3 (B1), 177.0 Bq/m3 (B2), and 189.2 Bq/m3 (B3) to a high of 210.1 Bq/m3 (B4). Indoor radon concentration was increased from the lower level to the upper level. The radon emanation rates from phosphogypsum were 4,234.1 mBq/m2/h and, 450.4 mBq/kg/h. The measurement results indicated that the phosphogypsum board used as building materials as well as the soil could affect the indoor radon concentration.

In this study, indoor radon concentrations were measured in 56 multiple-use facilities located in Gwangju area from December 2017 to December 2018. The average indoor radon concentration in underground space was 51.70 Bq/m3, and that of the 1st floor was 38.73 Bq/m3, indicating that the indoor radon concentration of underground space was higher than that of the 1st floor. The indoor radon concentration was investigated according to the presence or absence of underground space. The concentration of radon on the 1st floor with underground space was 37.25 Bq/m3, and the concentration of radon on the ground floor without underground space was 47.94 Bq/m3. In the absence of underground space, indoor radon concentration was high. The indoor radon concentration of buildings over 30 years old was 87.26 Bq/m3, indicating a significantly higher indoor radon concentration compared to those of buildings less than 30 years old. The indoor radon concentration was investigated according to the operation of a ventilator. The indoor radon concentration of space without an operating ventilator was 52.17 Bq/m3, and that of space with a ventilator in operation for more than 8 hours per day was 36.31 Bq/m3. This result shows that the indoor radon concentration in the space with an operating ventilator is lower than the space where the ventilator is not in operation. The indoor radon concentration in the space with an operating ventilation system was lower than that on the same floor of the same building, and the indoor radon concentration of enclosed space was about 4.4 times higher than that of open space in the same building. In addition, the indoor radon concentration was measured according to the spatial features. The concentration of indoor radon of enclosed space was 64.76 Bq/m3, which is higher than those of an open space and an active space.

Despite increasing public concern following mass media coverage regarding the risk of radon to human health and the need to control it, there remains a lack of infrastructure for measuring and mitigating radon. Against this backdrop, this paper is part of an effort to formulate an environment-management framework that can help resolve environmental issues relating to radon, ease fears regarding the associated risks, and provide radon-specific quality services. This study aimed to suggest locally applicable measures for training experts specializing in the fields of measuring and mitigating radon mainly based on US cases in which radon measurement and mitigation certification programs have been systematically run and supervised. Given the lack of both awareness on radon and experts in Korean circumstances, it is necessary to come up with a scheme to develop a radon-specific education program and a framework for expert accreditation. Thus, as groundwork for their introduction considering local circumstances, top-down measures led by the relevant department of government-led organizations, which will act as the control tower, should first be implemented to best utilize the insufficient human resources in this area. In addition, more systematic and detailed educational programs and an expert certification system need to be developed in accordance with the established foundations, and to support their consistent operation, a relevant administrative system should be constructed.

본 연구에서는 열분해잔사유(Pyrolysis Fuel Oil, PFO)를 이용한 Pitch계 활성탄소섬유를 제조하였다. 제조한 Pitch안정화 섬유의 탄화 및 활성화 온도를 850, 880, 900 ℃로 달리하여 각각 다른 샘플의 기공형성에 대한 영향을 알아보기 위해 BET 와 SEM을 이용하여 비교 분석하였다. 세 가지 샘플 ACF850, ACF880, ACF900를 분석한 결과 ACF880의 비표면적과 미세 기공표면적이 각각 1,420 m2·g-1, 1,270 m2·g-1으로 가장 높았으며, 외부비표면적과 BJH흡착누적공극표면에서 가장 낮은 중기공표면적이 도출되었다. 또한 N2가스 등온흡착곡선을 분석한 결과, 미세기공의 분포가 균일한 것을 확인할 수 있었다. ACF880은 흡착률 및 흡착속도에서도 가장 높은 결과값을 보이며, 흡착속도는 미세기공표면적과 비례하며 중기공표면적과 반비례함을 알 수 있었다. 제조한 Pitch계 활성탄소섬유를 라돈 연속측정방법을 통해 48시간 동안 측정한 결과 샘플 모두 라돈 흡착성능을 보였다. 제 조한 샘플 중 ACF880이 34.0%로 가장 높은 흡착률을 보였으며, ACF850이 29.5%로 가장 낮은 흡착률을 나타내었다. 이는 비표면적이 높을수록 흡착률이 높아지는 것을 알 수 있었다. 이를 선형회귀선 기울기로 환산하여 흡착속도로 확인한 결과 ACF880이 -1.89로 가장 빠른 것을 확인하였으며, ACF900이 -1.48로 가장 낮은 흡착속도를 보여 미세기공표면적이 높을수 록, 중기공표면적이 낮을수록 흡착속도가 증가하는 것을 알 수 있었다.

Radon (222Rn) gas is a main source of ionizing radiation of natural origin. It typically moves up through the ground to the air above and into building or home through cracks and other holes in the foundation. Significantly, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. This survey covers the determination of indoor radon concentrations at home from 2013 to 2014 in some areas of Gangwondo, every three months (seasonal) during one year using an alpha-track detector. The results showed that the annual average concentration of indoor radon was 84.5 Bq/m3 (GM: 64.5 Bq/m3) at homes. Indoor radon level was the highest in winter and the lowest in summer. Geometric mean radon concentration in winter was 1.03~2.58 times higher than other seasons. The data obtained from this study provide a basis for the preparation of legal regulation and public health protection manuals in this area.

This study aimed at providing fundamental information for development of governmental policy on radon management, investigated the radon levels of residential homes nationwide. It also suggested the necessity for policy development which focuses on management of the degree of harm through the installation of radon alarm devices and radon reduction consulting for homes with radon readings in excess of recommended threshold. Results showed that the radon level of the subjects of this study, 1,167 houses, was 97.3 ± 65.8 Bq/m3. Regionally, Seoul had the highest level, while Jeju had the lowest. In the first round of the investigation, the number of houses, with radon level which exceeded the recommended threshold, 148 Bq/m3, was 171. However, as a result of the radon alarm installation and radon reduction consultation, the indoor radon level of 137 households decreased to less than the recommended threshold. In the second round of the investigation, 80% of the households, the radon concentration of which exceeded the current recommended threshold in the first round, appeared to maintain their radon concentration below the recommended threshold. As a result of the communication about radon's harmfulness and the installation of the radon alarm device for recognition of harmful environments. It could be deduced from this result that the communication about harm contributes to the reduction of radon.

The objective of this study is to investigate indoor radon concentrations and identify influencing factors for one of the representative house type in South Korea. We surveyed 3,000 detached houses using alpha track (raduet) between November 2013 and March 2014. The Arithmetic mean radon concentration of the houses studied was 147.9 Bq/m3 (GM=106.4 Bq/m3), and the range was 11.8 to 1,936.6 Bq/m3. The Arithmetic mean radon concentration in living rooms was 134.2 Bq/m3 (GM=98.8 Bq/m3), much higher value compar with the Arithmetic mean radon concentration in bedrooms (153.0 Bq/m3). The year of constructon, basement status, ventilation frequency and heating period in a house were identified as major factors influencing indoor radon concentrations. The indoor radon concentrations in houses that were constructed prior to 1990 and that had basements were higher than those in the comparison groups. On the other hand, houses that were frequently ventilated and had a short heating period showed a tendency toward lower indoor radon concentration.

This study was performed as the preliminary research to calculate the concentration of radon exposure and the annual effective dose in public hot spring bath-house. The research found that public bathhouses are the primary cause of the indoor air radon concentration inside a hot spring bathhouse. The indoor radon concentration inside a bathhouse differs significantly by region and among bathhouses in the same region, indicating that the indoor air radon concentration is affected by many factors. The annual effective indoor radon dose by exposure is estimated to range from 1.2×10−2mSv/y to 2.5×10−2mSv/y. Since this research is considered as preliminary research, further and additional relevant research to more reliably calculate the result are necessary, including accumulative research for indoor radon concentrations, and research for exposure coefficients such as the behavior patterns of public bathhouse users, etc.

Developing proper reduction strategies of indoor radon which have been an important issue in Korea requires proper information on source characteristics a phosphate gypsum board which is a common building material used for inter-wall thermal protection in Korea could be a major source of indoor radon level. This study evaluated the correlation between indoor radon concentration and the attribution of gypsum board content in building materials. In this study we valuated indoor/outdoor radon from 58 facilities selected based on the information availability of gypsum content in the building material across 8 different cities in Korea. Our results showed that indoor radon concentrations were 2 to 3 times higher than outdoor but those results were not significantly attributed from gypsum contents in the building material. Indeed, phosphate content in gypsum board did not significantly play a role in indoor radon level variations. It is concluded that physical environmental condition such as temperature, relative humidity, radon exhalation rate out of each building materials, as well as pathway from external sources (e.g., soil) needs to be identified to develop indoor radon reduction strategies.

This study investigated the indoor radon concentration of 44 elementary schools in Gyeongsang-do from June 2008 to May 2009. The results obtained from this investigation are as follows. As for distribution of concentration based on seasons, the radon concentration was 77.4Bq/m³ in winter, 71.8Bq/m³ in autumn, 47.8Bq/m³ in spring and 40.4Bq/m³ in summer of Gyeongsangnam-do. And Gyeongsangbuk-do was 155.4Bq/m³ in winter, 124.3Bq/m³ in autumn, 82.7Bq/m³ in spring and 58.0Bq/m³ in summer, showing the highest concentration in winter. As for difference in radon concentration according to whether there is basement, concentration of schools having basement was 37.2Bq/m³, that of schools having no basement was 62.1Bq/m³ in Gyeongsangnam-do. In Gyeongsangbuk-do, schools having basement showed 53.9Bq/m³ of concentration and schools having no basement 124.7Bq/m³. Schools having no basement tend to show higher concentration. Indoor radon concentration according to the constructing year was 64.5Bq/m³ in schools built before 1990, 34.9Bq/m³ during 1990s and 32.8Bq/m³ during 2000s in Gyeongsangnam-do, and 110.5Bq/m³, 83.5Bq/m³ and 48.3Bq/m³ in Gyeongsangbuk-do respectively.

라돈은 자연방사성원소로 호흡을 통해 인체에 피폭된다. 본 연구에서는 2017년 6월 1일부터 2017년 8월 28일까지 3개월 동안 A대학의 8개 건축물에 대해 실내 라돈농도를 측정하여 비교하였고, 연간 유효선량을 도출하였다. 본 연구에서 A대학의 건축물 Hall G 와 Hall F의 라돈농도는 각각 81 Bq/㎥, 14 Bq/㎥ 로 나타났으며, 전체 조사 건축물의 평균 실내 라돈농도는 41.63 Bq/㎥로 나타났다. 대학 내 학습공간과 생활공간에 대한 연간 유효선량 환산치의 평균은 0.40 mSv/y이며 최대 연간 유효선량은 0.78 mSv/y, 최소 연간 유효선량은 0.13 mSv/y로 나타났다. 학교는 학생들이 오랜 시간 머무르는 공간이므로 건축물에 대한 적절한 환기와 관리를 통해 실내라돈 농도를 낮추는 것이 라돈에 대한 자연방사선 피폭을 낮추는 방법이다.

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 0.34314 Bq/m2·h for sample concrete. The radon concentration contribution to indoor radon in the house due to exhalation from the concrete was 31.006 ± 7.529 Bq/m3. The difference between the prediction concentration and actual measured concentration was believed to be due to the uncertainty resulting from the model implementation.