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.

This study analyzed the flow inside floating seedling equipment for Scapharca subcrenata. Due to the aging society of fishing villages, it is impossible to continuously input the labor force. Therefore, it is necessary to improve efficiency. Scapharca subcrenata has high per capita consumption. It serves as an important aquatic food resource. Scapharca subcrenata culture tends to be highly dependent on the natural environment. Production of Scapharca subcrenata is difficult to predict with low stability. In the past, manpower directly installed bamboo nets in mudflats. The seedling equipment devised in this study is a floating type and can be freely moved on the sea according to the prediction of Scapharca subcrenata generation. The flow around the floating seedling equipment was analyzed by numerical analysis. The physical phenomena of the flow around the net inside the floating seedling equipment were visualized. As a result, the space between the floating seedling equipment and the bottom net and the space between the net groups showed a lower flow rate than the inlet flow rate. It is expected that the low flow rate of the floating seedling equipment will have a positive effect on the attachment of Scapharca subcrenata.

To provide information needed for managing fish resources and protecting the ecosystem of Cheonsu Bay, bimonthly variations in species composition and abundance of fish eggs and larvae were investigated. The samples were collected by using bongo net at three different stations from February 2020 to December 2021. Fish eggs were divided into Engrualis japonicus and unidentified eggs, of which Engragulis japonicus accounted for 85.6% of the total eggs collected. A total of 21 species representing 17 families and 6 orders were collected. The three dominant species were Gobiidae spp, Thryssa hamiltonii and E. japonicus and these three species accounted for 74.1% in the total number of individuals. The number of species was highest in August, 2020 and lowest in February, 2020 and 2021; the number of individuals was highest in August, 2020 and lowest in February, 2020. Temporal changes in the abundances of pelagic eggs and larval fishes corresponded with temperature.

Distribution of airborne bacteria in the entire regions of South Korea was investigated and analyzed by region and type of multi-use facilities. At first, 10 public facilities were selected including general restaurant, retail store, public transport, retail market, apartment house, underground parking lot, financial institution, business facility, educational institution, and public toilet, which are located at the regions such as Seoul, Busan, Daejeon, Gwangju, Gyeonggi, Jeju, and Gangwon. The regional distribution of the floating bacteria was identified that Micrococcus sp. was highly prevalent in Seoul (21.5 percent). In Daejeon, Bacillus sp. was highly prevalent (12.4 percent). In Busan, Micrococcus sp. was highly prevalent (22.8 percent). In Gwangju, Bacillus sp. was 9.35%. In Gyeonggi, Micrococcus sp. was 13.7%, and in Gwangju and Jeju, Micrococcus sp. was 11.2 percent and 92%. All in all, Micrococcus sp. and Bacillus sp. were highly detected throughout the entire region and multi-use facilities. Next, whether or not these airborne bacteria could influence the health of people was examined using HaCat human skin cell line which is human epithermal Karatinocytes related to allergic dermatitis. Among these isolated microorganisms, the HaCat cell proliferation was decreased by Arthrobacter sp., Bacillus sp., Brachybacterium sp., Brevundimonas sp., Kocuria sp., Mammaliicoccus sp., Norcardia sp., Prestia sp., Phychrobacillus sp., and Rhodococcus sp., while it was affected by the other bacteria. Therefore, these results have suggested that the airborne floating bacteria could be considered as the marker for the environmental risk management against atopic dermatitis, and it is needed for controlling the bacteria number that suppressed the proliferation of HaCat cells.

This study measured the suspended fungal concentration in indoor multiple facilities nationwide. The regions were selected as representative cities by region: Seoul, Gyeonggi (Incheon), Gangwon, Gwangju, Daejeon, and Busan. A total of 2028 regional comparisons, including department stores, schools, public toilets, libraries, and banks, subway, sports facilities and comparative analysis were conducted for each multi-use facility industry. Among the nationwide, Among the regions, the average concentration of floating mold in indoor multi-use facilities was the lowest in Busan at 394.67 CFU/m3, followed by Gyeonggi and Incheon 487.90 CFU/m3, Seoul 542.84 CFU/m3, Daejeon 809.30 CFU/m3, Gangwon 1,145.22 CFU/m3, Gwangju was 1,371.10 CFU/m3 in the order. Busan was the lowest, and Gangwon was the highest. The reason that Busan, which has a high average temperature and population density, shows a lower mold concentration than Gangwon, is that floating mold in the indoor air is not affected by the external atmospheric environment, population density, and number of facility users. Although it cannot be said that there is no influence of the atmospheric environment, it was found that the indoor environment has different characteristics from the outdoor environment. The importance of air quality management has been confirmed, and further, it is necessary to subdivide the management standards by region and multi-use facilities, and the management standards need to be converted to maintenance rather than recommendations.

This study examines the effects of surrounding outdoor environmental characteristics in multi-use public facilities that are used by the susceptible population, on the concentration and distribution of indoor airborne bacteria. For this study, areas were divided into ‘factory area,’ ‘city area,’ and ‘forest area.’ The research was conducted from October 2017 to April 2018, and the selected target facilities were daycare centers, hospitals, postpartum care centers, and nursing homes for the elderly. In order to measure airborne bacteria, indoor air samples were collected using a six-stage viable particulate cascade impactor, and airborne bacteria samples were collected using MCE (Mixed cellulose esters) filters. Moreover, the outdoor airborne bacteria concentration was also measured to determine the concentration ratio (I/O ratio) of the total indoor airborne bacteria and total outdoor airborne bacteria concentrations. The results showed that the total outdoor airborne bacteria concentration was highest in the city area, with 74.2 ± 60.0 CFU/m3, and the lowest in the factory area, with 45.9 ± 35.8 CFU/m3. Furthermore, the distribution of the total outdoor airborne bacteria concentrations significantly differed across each surrounding environment (p < 0.05). On the other hand, no statistically significant difference in total indoor airborne bacteria concentrations, according to surrounding environments, was observed (p > 0.05). These findings suggest that the concentration of outdoor airborne bacteria differs across surrounding environments, unlike that of the indoor airborne bacteria.

The ichthyoplanktons were sampled by Bongo net to study the distribution of the eggs and larvae in the West coastal waters of Korea during the study period (February, May, August and October of 2017). Collected fish eggs were divided into Engraulis japonicus and unidentified species. The most dominant species, Engraulis japonicus accounted for 79.52% of the total fish egg, which was followed by unidentified species (20.48%). The total of 36 taxa in fish larvae were identified based on morphological and molecular characteristics. Fish larvae were dominant by Gobiidae species. 48.30% of the total catch in abundance, which was followed by Engraulis japonicus (31.86%). These two taxa composed 80.16% of the total collected fish larvae. The seasonal diversity index of species from the collected fish larvae in the West coastal waters in 2017 was 0.625-1.883 and the evenness index was 0.380-0.865. In addition, dominance index was 0.618-0.920 and richness was 0.573-3.189.

각기 다른 해양 환경 특성을 보이는 서해, 남해, 동해, 제주 연안역을 대상으로 춘계 (5월)와 하계 (8월)에 출현한 부유성 요각류의 군집구조에 대하여 분석하였다. 봄과 여름에 출현한 부유성 요각류는 총 73종이었으며, 이 중 연안종이 28종이었다. 봄 (49종)에 비해 여름 (58종)에 출현 종이 다양하였다. 요각류 출현 개체수는 봄과 여름 Chl-a 농도가 낮게 나타난 동해연안해역에서 가장 낮았으며, 봄에 Chl-a 농도가 높게 나타난 서해연안해역에서 출현 개체수가 높게 나타났다. 그러나 여름에 제주연안해역에서 Chl-a 농도가 0.6 μg L-1으로 낮게 나타났으나, 높은 출현 개체수를 보였다. 봄에 한국 연안에서 우점적으로 출현하는 요각류는 Acartia hongi, A. ohtsukai, Paracalanus parvus s. l., Oithona similis이었다. 여름에는 이들 종 이외에 A. omorii, A. pacifica, A. steueri, Calanus sinicus, Corycaeus affinis, Corycaeus sp., Pseudodaiptomus marinus, Tortanus forcipatus이었다. Paracalanus parvus s. l.은 봄에 조사 해역에서 최우점종 또는 차우점종으로 생태적 지위를 달리하였으나, 여름에는 전 조사해역에서 최우점종으로 출현하였다. 요각류 군집특성은 수온, 염분, Chl-a 농도 등의 환경 요인에 따라 서해, 남해, 동해, 제주 4구역으로 명확하게 구분되었다.

Long-span marine bridges are generally designed as long-span bridges in order to secure the running route of the ship and reduce the cost and time of the bridge pier construction. In long-span bridges, the range of load resistance transmitted by the superstructure and cable is determined by the mast and foundation. In the other words, the range of designable span length would be determined by the mast and foundation condition. The floating bridge is a type in which the superstructure is supported by the force of buoyancy without the pier mounted on the seabed so that the buoyancy of the floating bridge is balanced by the dead load and buoyancy of the structure. As a technique to overcome the weakness of existing long span bridges, it is possible to consider the type of cable supported bridges with floating tower. In this study, according to the tendon arrangement and initial tension distribution, the static global performance of the long-span bridges with floating tower were evaluated.

해양 HNS(Hazardous and Noxious Substances)의 유출 사고 시, 막대한 인명 피해와 환경 훼손을 피하기 위해 유출 사고 조기 예측과 정확한 확산 경로를 예측하는 것이 필수적이다. 본 연구의 최종목적은 전산유체역학을 이용하여 HNS사고가 발생하였을 때 위험구역을 적절히 예측할 수 있는 수치해석기법을 개발하고, 다양한 해양사고조건과 환경영향을 고려하여 근접역에서의 2차원 확산 특성을 고찰하고 확산 현상을 예측하기 위한 모델을 개발하는 것이다. 본 연구에서는 상용코드인 ANSYS FLUENT(V. 17.2)을 사용하여 근접역에서의 2차원 확산특성을 모사하고 분석하였다. 특히, 누출된 HNS의 위치별 농도를 예측하기 위해 종수송방정식(Species Transport Equation)을 이용하였으며 RANS(Reynolds-Averaged Navier-Stokes) 방정식과 표준 k-ε 모델을 이용하여 난류유동을 모사하였다. 해석된 결과는 문헌에서 얻어진 실험데이터와 상호비교하였으며 해수의 유속, HNS의 밀도에 따른 유층 두께, 해수면 HNS 평균 농도 그리고 HNS 전파 속도를 분석하였다. 유층 두께는 해류 유속에 따라 변화하며 변화 경향에 따라 두 구간으로 나눌 수 있다. 해류 전파 속도는 대체로 해류 유속과 선형적 비례관계를 갖는 것으로 나타났다. 해수면 평균 HNS 농도는 해류 유속에 선형적으로 비례하여 감소하며, HNS 밀도가 큰 경우 해수면 평균 HNS 체적 농도는 더 빠르게 감소하게 된다. 이러한 결과는 HNS 확산 특성을 분석하고 관련된 예측모델을 개발하는 데에 기여할 수 있다.

The aim of this study was to examine indoor fungal concentration and fungal volatile organic compounds(VOCs) in single-person households. A total of 22 houses occupied by one person were investigated in this study. 19 VOCs detected in the field were estimated as fungi-derived VOCs through a review of the literature, and 11 VOCs were confirmed as fungal VOCs by laboratory experiments. Exposure to fungal VOCs in the indoor environment has been confirmed to be highly influenced by airborne fungal concentration and indoor humidity. 3-octanone was characterized by a clear generation profile in Aspergilus versiocolor, and n-decane in Pencillum chrysogenum. ntetradecane emitted by Stachybotrys chartarum exhibited a tendency to occur consistently. The observations made in this study demonstrated that single-person households can easily be exposed to fungi, and MVOCs can be used as an indicator of fungal exposure in indoor environments.

This study investigated the emission characteristics of airborne particles and bacteria from six types of household vacuum cleaners in the closed chamber. A test cleaner without HEPA filter was examined focusing on the first one minute of initial operation, observing significant generation of airborne particles, and especially for particle size of 0.5 to 2.5 μm, the generation rate increased up to 68.5 × 103 particles/min. Concentrations of airborne particles and bacteria depends on the production year, the motor power, and the dust filter efficiency of the vacuum cleaner. The observed results should be taken into consideration in the design of the vacuum cleaner as well as how they are operated in indoor environment.

본 연구에서는 금강 하구역의 부유사 변동과 퇴적물의 상호연관성을 정량적으로 평가하고 그 기작을 규명하기 위하여 현장조사 및 수치실험을 수행하고 최종적으로 금강하구의 퇴적물 분포 및 이동 패턴 특성을 제시하고자 하였다. 1) 대조기 평균 부유사농도는 PC4를 제외한 모든 정점에서 하구둑 방류에 의한 영향이 미치는 것으로 보인다. 동계에는 PC3과 PC5에서 다른 정점에 비해 높게 나타나며, 이는 파랑과 방류량에 의해 발생된 부유사가 장항항 진입항로에서..

Recently, airborne fungi as indoor air pollutant have attention due to its health related problems such as asthma, rhinitis, sinusitis, atopy, pneumonia, building syndrome and etc.. However, it is considered that current laws and policies in Korea are not efficient to deal with these problems. Our research investigated influential factors and species distribution on the basis of previous research related to airborne fungi issue conduced in Korea by applying meta analysis technique. We selected 15 articles containing variables affecting fungi population such as outdoor air characteristics, temperature, location, and ventilation to evaluate significant factors. It was confirmed that airborne fungi level has partial correlation to those factors despite of limited sample size. It is required that the consistent and systematic research effort should be extended to characterize health effect caused by these fungi as well as to control them efficiently.