• Journal of the Korean Wood Science and Technology
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• 제49권2호
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• pp.122-133
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• 2021

The radon gas from nature mainly considers a cause of radon problems, and it is closely affect human life cycle. Korean yellow residual soil, Hwangtoh, widely used as a building material, is considered to be one of major sources of indoor radon. However, there have, as yet, been no studies about radon from Hwangtoh in mass market brands. Here, we investigated the indoor radon concentrations and exhalation rates in four Hwangtohs from different brand names and regional features. The Closed Chamber Method (CCM) conducted by a Continuous Radon Monitor (CRM) has been used for the rates of radon exhalation. Based on equations of previous references, the indoor radon concentrations were deducted. As a result, the radon surface exhalation rates resulted in the 1.4208 to 3.0293 Bq·㎡·h-1 range. Significant differences were found among Hwangtohs according to production regions. Materials with higher radon concentration required a longer time to reach a quasi-steady state in a given environment, in other words, the number of half-life cycles increased from a set starting point. The experimentally identified Hwangtohs demonstrated its safety for construction purposes. There exists, so far, a possibility to exert influence radon emanation due to unidentified factors. Therefore, it is necessary to corroborate with more research by increasing the number of Hwangtohs, considering the other references reported high radon exhalation rates. In addition, it is highly recommended that the radon exhalation rates should be measured for all building materials for preventing human health before the material usage.

• 한국산업보건학회지
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• 제26권3호
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• pp.334-341
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• 2016

Objectives: This study is aimed at examining radon exposure in offices and the factors that can influence the concentrations. Methods: Indoor radon concentrations in a total of 30 places were measured from January 18 to 21, 2016, targeting six buildings in Seoul with different completion years. The measurement was conducted according to the radon measurement guidelines for indoor air suggested by the Ministry of Environment. Results: As a result of comparing each average concentration, underground area concentration was $42.850{\pm}22.501Bq/m^3$, and that of the ground floors was $27.850{\pm}12.232Bq/m^3$, which was lower than the concentration in the underground areas and statistically significant (p=0.045). As a result of comparing the concentration according to whether or not outside air entered, the average concentration for ventilated areas was $24.876{\pm}11.833Bq/m^3$, and the average concentration for enclosed areas was $47.892{\pm}19.375Bq/m^3$. The concentration in ventilated areas was lower at a statistically significant level (p=0.001). Finally, as a result of the multiple regression analysis for evaluating the factors influencing radon concentration, only ventilation was significant (p=0.007). Conclusions: As a result of measuring radon in office buildings, there was no place that exceeding the recommended standard of the US EPA, but the concentration in poorly ventilated areas was measured to be high. An effort to manage radon concentration and reduce it through the improvement of ventilation systems, repeated measurement is necessary in the future.

• Journal of the Korean Wood Science and Technology
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• 제46권6호
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• pp.735-747
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• 2018

Radon radiation exposures in home have been posed as a potential cancer hazard. This research aims to present the basic data of the indoor radon concentration level by examining the radon exhalation rates of wood species. Radon exhalation rates from five commonly used wood species in Korean wood building construction were measured with Continuous Radon Monitor (CRM), Model 1028 (Sun Nuclear Co., USA) using the Closed Chamber Method (CCM). The mass exhalation rate was observed to vary from $0.00089Bq{\cdot}kg^{-1}{\cdot}h^{-1}$ to $0.00181Bq{\cdot}kg^{-1}{\cdot}h^{-1}$, whereas the surface exhalation rate was observed to be $0.00677-0.01517Bq{\cdot}m^{-2}{\cdot}h^{-1}$. The radon exhalation rate of Quercus accutissima Carruth (white oak) which has the highest density showed the highest figure among the five wood species, on the other hand, the rest of four species showed similar results which were similar to the radon exhalation rates of wood in the U.S.A. and Canada. The average of the concentration measured by the CCM represented well up to the second half-life period (7.7 days). Because result of these small quantities seems to indicate that radon exhalation from the tested wood species has almost negligible impact, the main culprit of the high indoor radon concentration is clearly derived from the background of surrounding wood house. Therefore, as a safety precaution, infrastructures made of wood materials should be designed with the consideration of influx of radon and built accordingly. Furthermore, it is highly desirable that wood will be needed to use for furniture and interior finishing material in indoor environment.

• 한국산업보건학회지
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• 제27권4호
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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.

• 한국대기환경학회지
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• 제27권6호
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• pp.692-702
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• 2011

For more effective indoor radon reduction policy and technique, we researched radon data analysis for some buildings in Seoul. Those buildings were categorized as dwelling, underground and office space and the variations of radon concentration and its sources were evaluated. The variations of radon concentrations of indoor space of buildings for a day were patterned specifically by dwelling habits and different environment. As for the new built apartments which were not yet moved in, their indoor radon concentrations were showed more than 3 times after applying interior assembly, and were 5 times higher than ones of rather old residences. As for the subway stations, the radon concentrations during off-run times were about 15% higher than run-times. 10% of radon seemed to be reduced by installation of platform screen doors. As for office space, radon concentrations during working hours were about 2.5 times higher than non-working hours. Plaster board are expected as a main source of radon for them. By radon measurement method for long-term, its data can be over estimated because it covers non-active time in office or public space. Therefore combination of short and long-term measurement method is required for effective and economic reduction. Furthermore importance of ventilation is requested as public information service for all dwelling space. And also standardization for radium content or radiation of radon is necessary.

• 자원환경지질
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• 제31권5호
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• pp.425-430
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• 1998

The results of radon $(^{222}Rn)$ concentrations and working levels (WL) for forty rooms in Kwanak Campus, Seoul National University on granite bedrock of Jurassic age showed that radon concentration have mean value of 3.0 pCi/L and 0.011 for working level. A number of rooms where these values exceed the EPA's action level are five (13%). It was also suggested that indoor basement rooms in poor ventilation condition can be classified as extremely high radon risk zone having more than 4 pCi/L and 0.020 WL. It was proved that inflow of soil-gas was a primary factor that governs indoor radon level by comparison of soil-gas radon concentrations with indoor radon concentrations.

• 한국방사선학회논문지
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• 제12권3호
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• pp.329-334
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• 2018

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 G와 Hall F의 라돈농도는 각각 $81Bq/m^3$, $14Bq/m^3$로 나타났으며, 전체 조사 건축물의 평균 실내 라돈농도는 $41.63Bq/m^3$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.

• 대한방사선기술학회지:방사선기술과학
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• 제27권2호
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• pp.29-33
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• 2004

1980년대 초까지 우리들은 라돈이 우리의 건강을 해친다는 생각을 하지 못하고 살아 왔다. 그러나 과학자들은 오래 전부터 우리가 사는 실내에 라돈 방사능의 위험이 도사리고 있다는 사실을 알게 되었다. 특히 우리나라에서는 라돈에 대한 위해와 인체에 미치는 영향에 대한 관심이 저조하다. 최근 들어 라돈 오염에 대한 의식을 가지고 서울 지하철의 일부 역, 학교 시설의 실내 공기, 주택 내 공기 중 라돈 문제의 중요성과 위험성에 대해 알리고 측정, 관리하는 관심을 가지게 되었다. 일반적으로 건물의 지반에서 방출된 라돈가스가 건물 바닥 갈라진 틈새 등을 통해 실내로 들어옴으로써 라돈이나 라돈낭핵종의 실내 공기 중 농도는 증가하게 된다. 따라서, 균열된 건물 바닥의 틈, 지하로부터 실내로 들어오는 상하수 파이프와 지반 사이에 틈새가 많을 수록 실내의 라돈 농도는 높아진다. 이와 같이, 라돈은 지각 뿐만 아니라 건축 자재물 상수, 취사용 천연가스 등을 통해서도 실내로 들어오지만 라돈의 85%이상은 지각으로부터 방출된 것이다. 폐암의 한 원인으로 지목 받는 라돈과 라돈 낭핵종에 의한 건강상의 위해는 토양 중 우라늄의 함량이 높은 지역과 광산의 갱내, 동굴, 주택과 같이 밀폐된 공간에서 특히 높아진다. 라돈 농도의 안전한 준위란 알 수 없으며 크든 작든 간에 항상 위험이 존재한다. 그러므로 중요한 것은 주택 및 건물 내에서 라돈의 농도를 낮춤으로써 폐암의 위험을 감소시키는 것이다. 따라서 일반 주택 라돈 농도 측정이 필요한 것으로 생각되어, 신틸레이터 라돈 모니터를 이용하여 월별로 라돈 농도를 측정하였다. 연구결과는 지상보다는 지하가 1년 내내 높게 나타났으며, 여름보다는 겨울이 높게 나타났다. 특히 미국 환경 보호청이 권고하는 주택 내 4 pCi를 넘는 달은 지하 내에서만 나타났으며, 12개월 중 4개월로 나타나 라돈 피폭 심각성을 알게 되었다. 그러므로 라돈에 관한 기준치의 설정과 규제 및 저감 대책의 마련이 시급하다는 생각이 들며, 라돈 농도 측정한 결과를 알리고자 한다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.92-93
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• 2017

Recently, there has been an increasing interest in natural radioactive gas radon(Rn-222), the problem of indoor air quality pollution to worldwide. It has been scientifically proven to be hazardous to various diseases such as lung cancer and skin cancer if the human body is exposed to long-term accumulation of atomic nuclei due to the destruction of radon and alpha lines. Based on the indoor air quality control policy, this study is a basic experiment in the manufacture of a selective elimination function to containing radon adsorption and reduction of radon concentration, which is used to absorb radioactive isotopes such as phosphorus and radon in indoor environment.

• 대한방사선기술학회지:방사선기술과학
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• 제40권1호
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• pp.127-134
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• 2017

본 연구는 실내 라돈 가스의 농도를 낮추기 위한 방법을 찾기 위해 건물의 준공연도, 건물의 용적, 환기 세 가지 변수에 따른 실내 라돈 농도를 비교, 측정하여 그 영향을 알아보고자 한다. 측정은 1973년에 건축이 되었고, 2011년에 증축이 된 건물의 6층을 대상으로 용적이 서로 다르고 준공연도가 1973년과 2011년인 6개의 강의실을 측정하였다. 준공연도에 따른 라돈농도를 비교하기 위해 4개의 강의실을 선정하였고, 용적에 따른 라돈농도를 비교하기 위해 준공연도가 같고 용적이 다른 강의실을 선정하였고, 환기에 따른 라돈농도를 비교하기 위해 6개의 강의실의 폐쇄와 환기를 시행하였다. 결과적으로 준공연도에 따른 라돈농도는 최근에 지어진 건물에서 라돈농도가 최대 4배 높게 나타났으며, 용적에 따른 라돈농도는 용적이 작을수록 높게 나타났다. 환기에 따른 라돈농도의 변화는 폐쇄 시보다 환기를 할 경우 약 80%의 감소율을 보였다. 특히, 준공연도가 최근이면서 용적이 작을수록 라돈농도가 높게 검출되었고, 세 가지 변수 중 환기가 라돈농도 감소에 가장 큰 영향을 끼쳐 라돈에 의한 피폭감소 효과를 기대할 수 있을 것으로 사료된다.