This study investigated the spatial distribution of dissolved organic carbon and the changes in tidal flat soil characteristics following the flooding season in the closed estuary of the Geumgang River basin. We found that after the flooding season, a brackish water area expanded due to increased river discharge, which also introduced low concentrations of dissolved organic carbon from the river. Dissolved inorganic carbon predominantly originated from the sea in proportion to salinity, indicating that in the closed estuary area, dissolved carbon supplied from the sea remained a significant source even after the flooding season. Additionally, a substantial amount of tidally transported silt and clay was deposited near the estuary dam after the flood, and its effects continued to influence the sediment characteristics downstream in the intertidal zone. As an empirical study in the closed estuary, our results are expected to contribute to conservation measures for the World Heritage Site in the area.

This study was carried out to examine the concentration and distribution characteristics of total airborne bacteria (TAB) and airborne mold in non-regulated public-use facilities. The arithmetic mean (AM) of the TAB in all facilities was 356.5 ± 419.3 CFU/m3, and the geometric means (GM) was 157.8 CFU/m3, which did not exceed the standard value of 800 CFU/m3. The highest concentration was 637.3 ± 372.0 CFU/m3 (GM: 534.9 CFU/m3) in the underground shopping mall. The AM of airborne mold in all facilities was 448.2 ± 429.6 CFU/m3 (GM: 285.4 CFU/m3), which did not exceed the standard value of 500 CFU/m3, but was close to it. In particular, subway station (AM: 661.5 ± 441.2 CFU/m3, GM: 540.0 CFU/ m3), large-scale store (AM: 587.6 ± 683.2 CFU/m3, GM: 297.8 CFU/m3), and private educational institute (AM: 528.8 ± 379.6 CFU/m3, GM: 373.7 CFU/m3) exceeded the standard. Operational taxonomic unit of 16S rDNA and ITS2 rDNA region was analyzed to profile bacteria and mold component in the air of the public-use facilities. As a result, Pseudomonas and Morganella are the major bacterial groups. Regarding mold, Aspergillus, Candida, Malassezia, and Penicillium are the major groups. Component of each airborne bacterial and mold groups varied depending on the type of public-use facilities.

Volatile organic compounds (VOCs) are chemicals to which humans are exposed frequently via various mediums, including vehicle emissions that contain fine dust and heavy metals, use of organic solvent building materials, furniture, and smoking. Exposure to high concentrations of VOCs may result in loss of consciousness, paralysis, convulsions, and, in the most severe cases, death. Therefore, the present study investigated the indoor and outdoor concentrations of total volatile organic compounds (TVOC) and five types of VOCs (benzene, toluene, styrene, m,p-xylene, and o-xylene) in apartments, a representative residential environment accounting for ~55% of the housing in the Seoul metropolitan area. The research was conducted over four seasons from May 2020 to February 2021, and the levels of VOC concentrations were analyzed by classifying them by season, weekday/weekend, and indoor/outdoor locations. The seasonal trend in VOC concentrations showed that TVOC concentration was highest in summer, with values of 1630.93 ± 1184.10 μg/m3 and 1610.36 ± 1363.43 μg/m3 for indoor and outdoor environments, respectively. The seasonal trends of the concentrations of the five types of VOCs showed that concentrations of benzene and toluene were highest in spring, the concentrations of m,p-xylene and o-xylene were highest in summer, and the concentration of styrene was highest in winter, irrespective of spatial characteristics such as indoor/outdoor environments. In all four seasons, the indoor concentrations were higher than the outdoor concentrations. These results reveal the spatial and temporal distribution characteristics of the VOCs and so can serve as useful basic data for managing indoor and outdoor levels of VOCs.

This study obtained the following conclusions using the measurement results of indoor and outdoor PM10 with regard to cardiovascular disease patients in Cheongju-area in November 2020. Most of the PM10 has an I/O ratio of less than 1, which is an outdoor source. Since we measured once and twice time, Without the air purifier device’s working status, there were no concentration changes of PM10 in the first and second indoor areas. As for the concentration of PM10 according to the living environment, the distribution of PM10 is higher indoors than outdoors when the residential area is 30 m2 or more, and the outdoor PM10 concentration tends to be high when the distance to the road is within 50 m. The more time spent indoors, the higher the indoor PM10 concentration. The smaller the ventilation time and frequency, the longer the cooking time was, and the higher the number of cooking times, the higher the concentration of PM10 could be. The indoor PM10 contribution ratio through multiple regression analysis showed the possibility of increasing indoor PM10 as β = 28.590 when the time spent indoors was longer than 16 hours (p<0.05). The result regarding PM10 exposure reveals that PM10 can be inhaled not only indoors but also outdoors, and the subjects of this study appear to have lived indoors for about 16 hours or longer on a daily basis, which may affect their health regardless of gender.

We investigated the distributions of airborne radon concentration on the platforms of the stations of Seoul Metro by the underground depth of each subway line, and explored the correlation between the radon concentration and the depth and geological conditions around each underground station. The measurements of radon levels were performed in 254 subway stations within Seoul Metro Lines 1 to 8 using the passive sampler (RADUET). Radon concentration data from 2007 to 2017, as well as the depth of each subway station were obtained from the Seoul Metro corporation. The geological information of each subway station were purchased from the Korea Institute of Geoscience and Mineral Resources. Student t-test and correlation analyses were performed to compare the levels of radon by the depth of subway stations, and to investigate the association of radon levels based on geological information. The geometric mean concentration of the all subway stations was 27.9 Bq/m3 ( range, 3 . 7Bq/ m3~124.0 Bq/m3). The depth of Lines 5-8 (geometric mean, –20.3 m) was significantly deeper by about 50% or more than that of Lines 1-4 (–13.1 m) (P<0.01). The radon levels increased significantly in deeper depths and as the number of Lines increased (P<0.05). A significant higher mean concentration of radon above the igneous rock (33.0 Bq/m3) was observed, comparing to that of non-igneous rock (27.5 Bq/m3) (P<0.00001). Our findings indicate that the deeper the subway is built or the more it is constructed on the granite area, the more careful management, including frequent ventilation and measurement monitoring, is necessary.

This study was conducted as a part of the research for the “Development of Big Data Analysis Techniques and AI-based Integrated Support System for Energy-Environment Management.” We collected research results on characterization of distribution of fine dust and re-analyzed using meta-analysis techniques to build “big data” with high potential for school environments. The results of prior studies on the characteristics of fine dust concentration distribution in a school environment conducted in Korea were collected and re-analyzed the results using the metaanalysis technique. In this manner, the variables that could be used to derive the independent variables needed to produce the e-coding book prior to the big data collection, were first derived. The possibility of using the data as independent variables was then evaluated. In this study, three variables: “elementary school vs. middle school vs. high school,” “general classroom vs. special classroom,” and “new classroom vs. old classroom” were evaluated for their application as major classification variables with priority. The necessity of being derived as a major classification variable was examined by testing the difference in fine dust concentration distribution in the school environment by each variable case. Results showed that “elementary school vs. middle school vs high school” and “general classroom vs. special classroom” could be used as independent variables, while “new classroom vs. old classroom” was less likely to be used as an independent variable.

본 연구에서는 정삼투 중공사막 모듈에서 중공사막의 가닥을 비틀어 배치하였을 때의 효과를 알아보기 위해 CFD 전산 유체 역학 프로그램을 통해 5개의 다른 각도로 비틀린 중공사막 모듈을 설계하고 시뮬레이션하여 비틀리지 않은 모듈과 비교하였다. 실험 결과, 중공사막이 비틀렸을 때, 모듈 내부의 유도 용액의 농도가 비틀리지 않을 때에 비해 고르게 분포하였 다. 모듈 입구의 압력은 중공사막의 비틀림과 관계없이 일정한 값을 보였지만 출구의 압력은 중공사막이 비틀린 정도가 커질 수록 증가하는 추세를 보였다. 출구의 압력이 높아짐에 따라 막 내부의 유체 속도가 감소하고 모듈 체류 시간이 증가하여 막 사이의 물질 교환이 원활하게 이루어질 것으로 예측된다. 이는 결과적으로 막이 비틀려 있을 때의 모듈 플럭스가 투과 수량 이 차지하는 비율이 그렇지 않을 때에 비해 2배 증가하였다.

The goal of this study was to measure the indoor and outdoor fine and ultrafine particulate matter concentrations (PM10, PM1.0) of some houses in Yeosu and in S university in Asan from March to September 2018. PM10 concentration in indoor air in Yeosu area was 18.25 μg/m3, while for outdoor air it was 14.53 μg/m3. PM1.0 concentration in indoor air in the Asan area was 1.70 μg/m3, while for outdoor air it was 1.76 μg/m3, showing a similar trend. Heavy metal concentrations in the Yeosu region were the highest, at Mn 2.81 μg/m3, Cr 1.30 μg/ m3, and Ni 1.11 μg/m3 indoors. Outside, similar concentrations were found, at Cr 3.44 μg/m3, Mn, 2.60 μg/m3, and Ni 1.71 μg/m3. Our analysis of indoor and outdoor PM concentrations in the Asan region, which was carried out using the MOUDI (Micro-orifice Uniform Deposit Impactor) technique, found that PM concentration is related to each particle size concentration, as the concentration of 18 μm and 18-10 μm inside tends to increase by 3.2- 1.8 μm and 0.56-0.32 μm.

수산자원보호구역의 유기물과 중금속 분포특성을 파악하기 위하여 2017년 2월 남서해연안 5개 수산자원보호구역(가막만, 여자 만, 득량만, 완도연안, 영광연안) 54개 정점에서 표층 퇴적물을 채취하여 입도, 강열감량(IL), 화학적산소요구량(COD), 산휘발성황화물(AVS) 및 중금속(As, Cd, Cr, Cu, Fe, Hg, Pb, Zn)을 분석하였다. 평균입도(Mz)는 평균 7.4±0.1Ø 였으며, 주로 세립한 니(mud) 퇴적물로 구성되어 있었다. IL, COD와 AVS의 평균농도는 각각 4.63±0.96 %, 13.0±3.1 mgO2/g·dry, 0.092±0.124 mgS/g·dry 였으며, 영광연안이 다른 보호구역에 비해 낮았다. 중금속의 평균농도는 각각 As 7.5±0.9 mg/kg, Cd 0.04±0.02 mg/kg, Cr 70.2±9.7 mg/kg, Cu 15.3±2.8 mg/kg, Fe 3.3±0.5 %, Hg 0.014±0.003 mg/kg, Pb 25.0±6.0 mg/kg, Zn 99±14 mg/kg 였으며, 보호구역내 대부분 만 안쪽에서 높고 만 외측 및 외측연안에서 낮은 특성을 보였다. 퇴적물기준 (sediment quality guidelines, SQGs), 오염부하량지수(pollution load index, PLI), 생태계위해도지수(ecological risk index, ERI)를 사용하여 퇴적물 중 금속 오염도를 평가한 결과, 남서해연안 수산자원보호구역 퇴적물은 수산생물 및 저서생물에 영향을 주지 않는 안전한 중금속 농도를 유지 하고 있었다.

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.

To reduce subway passengers’ exposure to PM 10 (particulate matter less than 10 micrometers), management of PM 10 concentration in underground stations is critical. In this study, we attempted to investigate the distribution of airflow PM 10 concentration in an underground station. The numerical simulations were performed using computational fluid dynamics. In order to apply to CFD, measurement of air volume (supplied and exhausted air) and PM 10 concentration were conducted at the concourse and platform areas of the underground station. The results of the simulation agreed with the actual PM 10 concentration, and we confirmed the distribution of PM 10 concentration depending on air volume conditions. This result will be helpful to reduce the PM 10 in an underground station when using ventilation system.

자란만 퇴적물 중 유기물과 중금속의 농도분포와 오염현황을 파악하기 위하여 2014년 11월 15개 정점에서 표층 퇴적물을 채취하여 입도, 총유기탄소(TOC), 총질소(TN) 및 중금속(As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Zn)을 분석하였다. 평균입도(Mz)는 8.6-9.8Ø(9.3±0.3Ø) 사이였으며, 니(Mud)와 점토(Clay)의 세립한 퇴적물로 구성되어 있었다. TOC와 TN은 각각 1.51-2.39%(1.74±0.22%), 0.20-0.33%(0.23±0.03%)의 범위로 전반적으로 공간적인 농도차이를 보이지 않았다. 모든 퇴적물에서 C/N 비 값은 5-10 사이를 보여 자란만 표층 퇴적물 중 유기물은 주로 해역 내에서 발생한 해양기원성 유기물인 것으로 파악되었다. 중금속 중 Cr, Fe, Mn은 만의 입구 쪽에서 높고 그 외 중금속(As, Cd, Cu, Hg, Pb, Zn)은 자란만의 안쪽에서 높은 농도를 보였다. 한편, 퇴적물 기준(SQGs), 농축계수(EF), 농집지수(Igeo), 오염부하량지수(PLI), 생태계위해도지수(ERI) 등 다양한 평가기법을 이용하여 자란만 표층 퇴적물의 중금속에 대한 오염정도를 살펴본 결과, Cd, Cr, Cu, Hg, Pb, Zn은 오염되지 않은 상태이거나 일부해역에서 오염된 상태를 보였지만 As는 전 해역에서 높은 오염도를 보였다. 또한, 분석된 모든 중금속 농도를 고려한 전체적인 오염도를 살펴본 결과, 모든 해역에서 중금속에 대하여 오염되었고 특히, 일부 해역에서는 저서생물에 위해성을 줄 수 있는 상태인 것으로 파악되었다. 따라서, 자란만 내 양식 수산물의 안전성 확보와 지속적인 어장 생산성 유지를 위해서 자란만 퇴적물 내 유기물과 중금속의 오염원에 대한 체계적인 관리가 필요하다.

This study aims to analyze the effects of 4 directions of wind, wind speed, year of construction of slate roofs, installation area and other factors on the concentration and size distribution of airborne fiber particles in farmhouses with a slate roof containing asbestos. Airborne fiber particle samples were collected from the air in six houses with a slate roof containing asbestos using a high flow rate pump (10 L/min) for 2 hours, three times a day with a different condition, 72 times in total. The airborne fiber particle concentrations were measured using a phase contrast microscope, and the size of fiber particles of 72 samples in total was estimated using the mean value of those in each sample measured at 100 with a field of view. The total average concentration of fiber particles collected from in the air in four directions of the targeted farmhouses was 2.83 fiber/L, and its maximum concentration was 5.75 fiber/L, which means that among all samples there was no place that exceeded 10 fiber/L, a recommended indoor air quality standard. The average size of the fiber particles was 11.55 μm, and the maximum size was 40 μm. A multiple regression analysis of factors affecting the concentration and size of fiber particles in the air collected from the farmhouses with a slate roof containing asbestos found that the closer to the main wind direction (p<0.001) and the faster the average wind speed (p<0.05), the fiber particles concentration became significantly higher. In this case, the coefficient of determination was 52.8%. It was also found that the wider the total area of the slate roof (p<0.001) and the slower the average wind speed (p<0.05), the longer the fiber particles; the coefficient of determination for this finding was 19.6%. The concentration of fiber particles in the air of farmhouses with a slate roof appeared to be the highest under the main wind direction, and became significantly higher as the wind speed became faster. This proved that fiber particles were leaked from the slate roof. The size of the fiber particles became significantly longer as the area of the slate roof became wider and the wind speed became slower.

About half of the South Korean population lives in the three major metropolitan areas, which are Seoul, Kyeonggi and Incheon. Among this group, more than 50% live in apartments. In this study, the relationship between the concentration of indoor VOCs and environmental factors was investigated in metropolitan apartments in the occupation stage. The maximum concentration of TVOC (total volatile organic compounds) was monitored in spring season. Among the identified VOCs, toluene was present in the highest amount, followed by terpene, aldehyde and hydrocarbon. Due to the specific indoor sources, the I/O ratio of terpene (e.g. d-limonene, α-pinene, and β-pinene) was relatively higher than that of the others. The construction year and length of residence were revealed as the environmental factors having the greatest influence on the concentration of indoor benzene, toluene, ethylbenzene, xylene, styrene and hydrocarbon, and the relationship was statistically significant. The floor and size of the apartment influenced the levels of indoor nonanal. The relationships between individual VOCs showed highly positive correlations that are statistically significant. Through the relationship study, it was found that factors including newly built apartment, short period of time after moving in, high floors and small floor area were the main factors inducing an increased concentration of indoor VOCs in apartments.

Soil salinity at newly reclaimed land in west coast of Korea is highly variable and depending on soil characteristics and weather conditions. The objective of this study was to evaluate the spatiotemporal distribution characteristics changes on soil electrical conductivity and exchangeable sodium percentage in Saemangeum newly reclaimed land. Experimental sites was selected at Gyehwa (35o75'N, 126o60'E) in Saemangeum reclaimed land and their dominant soil series was Munpo (coarseloamy, mixed, non-acid, mesic, typic Fluvaquents). Soil samples were periodically collected at 0 ~ 20 cm and 20 ~ 40 cm layer from each site. Soil electrical conductivity had a wide range from 0.15 to 41.76 dS/m, which was variable according to the weather conditions. The average soil electrical conductivity from March 2014 to 2015 was 6.4 and 3.4 dS/m at Gyehwa in Seamangeum reclaimed land. Calcium concentration in soil solution was negatively correlated with soil electrical conductivity and soluble sodium. Soluble sodium concentration had great variations and it was the most influencing single factor for temporal variations of soil electrical conductivity regardless of soil textural properties. The characteristics of Saemangeum reclaimed land had different shares of saline and sodic properties during the experimental period. Our results indicate that persistent monitoring and modeling on soil salinity at coastal tide land is fundamental and the results can provide some useful information for deciding management plans for diverse utilization or to reduce salt damage for stable crop production at reclaimed tidal land.

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.

We have performed CFD simulation and analyzed flow and concentration fields for the basic data of the ventilation system for removing pollutants which were produced in a lecture room. The flow patterns indicated differently according to the arrangement of openings and the concentration distribution of pollutants were showed higher and lower because of the effect of that flow patterns. In the case of arranging the openings to the upper and lower side, the stagnation appearance of flow formed in the interested space. In the case of arranging the openings to the right and left side, the stagnation of high concentration pollutants appeared in the middle area of the interested space. On the increasing exhaust velocity, the distribution of pollutants appeared similar to the normal case, but the concentration of pollutants were lower.

산업 및 도시 개발로 오염이 심화되고 있는 진해만에서 생물을 이용한 오염도 모니터링을 위하여 부착성 이매패류인 진주담치를 이용하여 중금속 분석을 실시하였다. 중금속 농도는 원소 및 정점에 따라 차이가 있었는데 내만해역 또는 하수처리장 방류지역에 인접한 정점에서 높게 나타나는 원소가 있었다. 국내 및 국외 과거 자료와의 비교에서는 전체적으로 본 조사 결과가 낮은 값을 보였다. 특히 진해만의 소형만의 하나인 고현만의 조선소 주변해역 진주담치 중..

In this study, the concentration distribution of radon, we analyzed from 55 house, 37 government office, 54 schoolfrom June 2008-June 2011 in Chungnam area. From the result of surveying indoor radon degree of 146 facilities,the annual average geometric concentration of indoor radon was 69.4Bq/m³, 40.5Bq/m³, 51.4Bq/m³ in house,government office, school respectively. As for distribution of concentration based on seasons, the radonconcentration showed the highest concentration in winter in all facilities. According to the result of the analysisby dividing the construction year, into before 60s, 60-70s, 80-90s and 2000s, the radon concentration was lowerin all the newly constructed facilities. As for difference in radon concentration due to the presence or absence ofbasement, concentration of house, government office and schools having basement was 52.2Bq/m³, 44.5Bq/m³,36.4Bq/m³ that of having no basement was 75.2Bq/m³, 53.6Bq/m³, 67.4Bq/m³ respectively. Place having nobasement tend to show higher concentration.