Air flow field characteristics in a compact chamber system are indispensable for the efficient development of vehicle aerodynamic performance. In this study, air flow and velocity uniformity in the chamber system were numerically analyzed using the CFD method. Air flows at a uniform velocity from the outlet of the blower, passes fast through the heat exchanger with partial pressure difference, and then moves into the blower inlet. Overall pressure drop through the fan gradually increases with the flow rate. The uniformity varies along the test section, decreasing by 5-10% with distance from the nozzle. These predicted results can be widely used as basic conceptual design data for an efficient vehicle chamber system.

Yeosu National Industrial Complex is one of Korea’s representative petrochemical industrial complexes where crude oil refining and petrochemical companies are concentrated. According to the results of the 2021 chemical emissions survey, during the process of manufacturing, storage, and transportation at the Yeosu National Industrial Complex, various hazardous chemicals, including hazardous air pollutants, volatile organic compounds and odorous substances are being emitted into the air, affecting the surrounding environment and the health of residents. The Ministry of Environment is applying strengthened standards by designating the Yeosu National Industrial Complex as an air conservation special measure area and establishing odor management areas to manage the air environment. Nevertheless, odor complaints continue to be registered and related complaints increase when turnaround work is carried out. Since air emissions are not counted during periods of turnaround as normal operations are temporarily suspended, it was difficult to establish policies to reduce odor complaints because the source of emissions and emission quantities cannot be ascertained with certainty. In this study, the extensive Yeosu National Industrial Complex was subdivided into 4 areas using a mobile vehicle equipped with PTR-ToF-MS capable of real-time analysis without sample pretreatment being carried out. Measurements were repeated during the day, night, and dawn while moving around the internal boundary of the plant and the boundary of each region where turnaround activities were being carried out. As a result, the recorded measurement for acrylonitrile was the highest at 6340.0 ppb and propyne and propene were measured the most frequently at 128 times each. Based on these results, it will be possible to help reduce emissions through process improvement by efficiently operating air measurement networks and odor surveys that conduct regular measurements throughout the year and providing actual measurement data to the plant. Also, it will help reduce odor complaints and establish systematic air management policies.

In this experiment, the engine (i30 FD) was fabricated and installed in front of the intake manifold of the gasoline engine of the 2010 1,600cc MPI(Multi Point Injection) 4-cylinder 16-valve DOHC(Double Over Head Camshaft) electronic control fuel injection system, and the plenum chamber was 150cc, 300cc, 4. The engine rotation speed was increased from 1000rpm to 3000rpm by 500rpm, and the pressure change and engine volume efficiency change of the air intake manifold runner were analyzed. In this study, the volume of air flowing into the cylinder was maximized through the stabilization of pressure vibration in the intake manifold runner part due to the engine operation condition and the volume change of the intake manifold plenum chamber, and the uniform distribution rate of the intake air was confirmed by minimizing the interference between the cylinders. It has in the purpose to analyze the flow characteristic at the intake manifold inside. It can apply to obtain the optimal design factor.

Temperature distribution studies were performed in steam-air retort to investigate the influence of various processing conditions (come-up time, sterilization temperature, and internal pressure throughout the steam-air retort). Retort temperature data were analyzed for temperature deviations during holding phase, maximum temperature difference between test locations at the beginning and after 1, 3, and 5 min of the holding phase, and box-and-whiskers plots for each location during the holding phase. The results showed that high sterilization temperature led to a more uniform temperature distribution than low sterilization temperature (pasteurization). In pasteurization condition, the temperature stability was slightly increased by increasing pressure during the holding phase. On the other hand, the temperature stability was slightly decreased in high sterilization temperature condition. Programming of the comeup phase did not affect the temperature uniformity. In addition, the slowest cold spot was found at the bottom floor during the holding phase in all conditions. This study determined that the temperature distribution is affected by retort processing conditions, but the steam-air retort needs more validation tests for temperature stability.

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.

Senior citizens are reported to be highly sensitive to environmental pollutants, including fine particulate matter. The purpose of this study is to investigate the distributions of fine particulate matter concentrations in town halls and senior citizens’ halls, where senior citizens typically spend a lot of time. The results of this investigation will serve as fundamental data for conducting indoor air quality studies and establishing a regional environmental health policy governing senior citizens’ facilities in Yeongwol county in the future. From January 4 to February 1, 2017, PM10 and PM2.5 concentrations in 170 seniors’ facilities located in Yeongwol county were measured. The average concentrations of PM10 and PM2.5 that were measured from each seniors’ facility chosen from Yeongwol county were 25.1 ± 18.9 μg/m3and 12.5 ± 9.3 μg/m3 respectively. Average concentrations and the average of maximum concentrations were lower than the living space standard of 100 μg/m3 for PM10 and the atmospheric environment standard of 50 μg/m3 for PM2.5, which were set by the Ministry of Environment for populations vulnerable to environmental pollution. As a result of analyzing the sources in seniors’ facilities in Yeongwol county during the winter months, it was found that indoor sources of air pollution such as cooking is main sources rather than outdoor sources of air pollution.

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.

The spatial resolution of 3-Dimensional numerical model has a very important influence on the model result. The land-use and orographic effect is also influenced by the spatial resolution of the model. A large errors in model performance are produced depending on the terrain complexity. In this study we performed Air Quality Forecast model (AQF) simulation and analyzed the change in the ozone concentration depending on spatial resolution at small and medium-sized mixed areas with urban and rural area types. As the result, improving the spatial resolution improved the simulation of the downward trend of ozone at night. This was mainly due to improvement of local concentration contaminants at fragmented grid. In the case of wind speed, the model with high-resolution shows better agreement with observation at night.

Deposits discharged through the cleaning mainly were cement mortar, bitumen paintings and rust pieces, and fragments of perforation, stones and gravels. Deposits were more removed through swabbing pig cleaning rather than air scouring cleaning on the whole. However, air scouring cleaning were not influenced by the constraint conditions such as a change in the diameter or the presence of the valve in water mains compare to swabbing pig cleaning. So, it was thought that air scouring cleaning might be more favorable to water distribution network cleaning in the future. After the cleaning, water quality including residual chlorine and turbidity also was improved because of the removal of a significant amount of the deposits. Therefore, if the cleaning is continuously and regularly implemented in water mains, it is expected that it will help to recover the reliability and to preserve the health of water quality.

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.

It was investigated the state information for the atmospheric conditions around Dang-jin industrial complex in Chungnam area may be polluted by the constructing steel industrial complex. It is aimed at characterization of the fine particulate matter and other air pollutants involved in it. Samples were collected two sites for monitoring point representing steel industrial complex and one site which is placed a remote and secluded from this industrial complex, and the concentration of PM10, heavy metals, and ion components were analyzed. As a results, PM10 average concentration was 64.6㎍/㎥ for the adjacent site before Hyundai Steel Company, 70.5㎍/㎥ in Bugok immigration settlement complex, and 56.5㎍/㎥ for Jeonggok-ri contrastive point. The distribution of heavy metals was detected as very low level for all sampling points. According to the result of statistical evaluation for the heavy metal analysis, variation range of Cu, Mn, Ca, Fe, and Mg were significant higher than others. Also, the seasonal concentration change trend of heavy metals was remarkable strong in spring and low in summer because of instable meteorological phenomena such as yellow dust happened in spring. Monthly changing pattern of a sulphate ion has kept unusually high level for summer period different other components. Relationship among PM10, heavy metal, and ion component were analyzed that high positive correlation coefficient for PM10 between Fe, Mn, Pb, Ca, Mg, Cd, Al in order and PM10 between NO3-, Cl- successively. Accordingly, it is suggested that a present atmospheric conditions of the surrounding area of Dang-jin steel industrial complex is considered to be good level. Although air pollutants in emissions from their complex were below the existing emission limit, it is regarded that the systematic and continuous research is needed to preserve clean air through atmospheric monitoring, source tracing research, and citizen's surveillance for the fine particulate matter.

본 연구는 표준 개방한우사 설계도에서 제시된 처마의 길이보다 짧게 개방한우사의 처마가 시설되었을 때 지붕의 기울기와 동일하게 처마를 연장하는 것과 기둥 위치에서 수직으로 비가림시설을 하는 경우, 어느 우사가 우의 더위 스트레스 경감, 우방 바닥 건조, 비 들이침 및 환기효율에 더 유리한지를 규명하기 위하여 표준길이의 처마와 3종의 비가림 시설을 대상으로 computational fluid dynamics (CFD) 시뮬레이션기법을 이용하여 수행하였다. 여름철의 평균 풍속인 1.2 m/s에 근거하여 시뮬레이션을 한 결과, 여러 형태로 수직 비가림시설을 설치하는 것보다 표준 처마길이로 시공하는 것이 환기 및 풍속분포가 양호하였다. 따라서 수직으로 비가림시설을 하는 것보다는 축사 표준설계도에 제시된 처마 길이 정도까지 지붕의 기울기와 같게 처마를 연장하는 것이 유리하다.

Recently Korean government introduced and strengthened the environmental polices to manage and enhance indoor air quality as a major assignment. As a result,“Indoor Air Quality Management Act”has been activated since May 2004. However, among many multi-usage facilities, the school environment has been excluded from such regulations. Thus, the purpose of this study is to survey indoor aerosol and CO2 concentrations in a university library which is one of major school facilities. Concentrations of PM10, PM2.5, and PM1 were intensively measured every 5 minute interval by means of a dust monitor with light-scattering principle. The mini-volume air samplers were used further to analyze inorganic elemental compositions of PM10 and to inter-compare with the dust monitor. Carbon dioxide was simultaneously monitored by a multi-gas monitor equipped with a non-dispersive infrared system. PM10 concentrations did not exceed the indoor air quality standard(150㎍/㎥) for all the sampling places. However, quick and steep increases of aerosol concentration were observed during the Asian Dust storm period. In addition, the concentration of PM10(74.1㎍/㎥) in the main university office was the highest among the entire sampling places. Although there was no specific pollution source in the library, the levels of aerosol and CO2 increased quickly due to various outdoor sources and human activities. The average CO2 concentration measured in three reading rooms, where ventilation was not fully operated, exceeded the indoor air quality standard of 1,000 ppm. Based on these case studies, effective management and reduction plans for indoor aerosol and CO2 were suggested for the large scale public buildings including university libraries.

This study was surveyed to evaluate and recognize the distribution characteristics of indoor air pollutants(IAPs) such as the total volatile organic compounds(VOCs), formaldehyde(HCHO), PM10, carbon dioxide(CO2), nitrogen dioxide(NO2), ozone(O3) and radon in 10 elementary schools located in urban, rural, and industrial complex area from November 2005 to February 2006. The average concentration of IAPs were 117.9㎍/㎥ as in PM10, 1,971ppm as in CO2, 486.6㎍/㎥ as in TVOC. These chemical's concentration was exceeded the indoor air standards of the Department of Education in Korea. The indoor concentrations of ozone and toluene was lower than that of outdoor and other pollutants showed the opposite tendency. In schools located industrial complex area, the outdoor concentration of TVOC was higher than that of urban and rural area. Based on the results above, PM10, CO2, TVOC have to be in the order of priority to improve the indoor environment in school. Also it should be performed in the detailed survey considered by the seasonal variation because this study showed cross-sectional results.

To design an efficient and acceptable indoor air environment in a badminton gymnasium, it is important to study the velocity and temperature field in the conditioned room. For diverse airflow patterns, the k- c models with wall function near solid boundaries are adopted to simulate airflow distribution in the gymnasium. The simulated result is analyzed in this paper, and it provides the important reference for the design of air condition system and optimization of the project. CFD is effective design tool for air flow in large space, for it can give the velocity and temperature values at any point quantitatively.

동절기 시설내 온도분포를 균일하게 하기 위하여 온풍난방기용 이중덕트를 개발하고자 본 연구를 수행한 결과 관행 온풍덕트의 각 지점간 토출구 송풍온도 차이가 13 ～ 14℃인데 비하여 개선형 덕트인 이중덕트의 토출구 송풍온도 차이가 3 ～ 4℃로 나타나 각 지점간의 온도 불균형이 크게 개선되었으며 이중덕트의 각지점간의 생육정도도 관행덕트에 비해 크게 향상 된 것으로 나타났다. 수량에 있어서도 관행덕트를 사용한 재배시설에서 10a당 3,924kg에 비하여 이중덕트를 사용한 재배가 4,616kg으로 약 17%가 증수되었다. 그리고 반촉성 재배기간 동안 난방에 소요된 연료소모량은 관행덕트가 3,724ι/10a인데 비하여 이중덕트가 3,233ι 13%의 연료절감효과가 있다.

현재 경북지방의 수박 및 참외재배에 가장 많이 이용되고 있는 대형터널 하우스의 온도 변화를 분석한 결과, 터널하우스 내 기온은 일몰과 함께 강하하여 외기온과 비슷한 온도를 유지하는 시간은 일몰 후 약 2시간 30분 전후로 나타났으며, 자연환기장치인 환기공 및 수동식 측창이 설치되어 재배기간중 하우스내 최고기온은 40℃ 이상 유지되지는 않았다. 하우스야간온도는 높이별 위치에 관계없이 거의 같은 온도로 유지되었으며, 재배기간중 야간온도는 외기온보다 2~3℃정도 높게 유지할 수 있었지만, 외기온이 적온 이하일 때는 보온의 필요성이 있었다. 또 재배기간중 20cm 깊이의 지온은 20℃ 이상을 유지할 수 있어서 적정지온 확보에는 문제가 없었으며, 일변동폭은 3~5℃ 정도이고 관수로 인한 지온저하는 5~6℃ 정도였다

In this study, we investigated the characteristics of Volatile Organic Compounds(VOCs) emission from painting and printing facilities in the Pyeongdong industrial complex in Gwangju. In addition, the objective was to understand the distribution characteristics of VOCs in the ambient air in industrial complexes affected by painting and printing facilities. The painting facility mainly emitted toluene, acetone, butyl acetate, 4-methyl-2-pentanone, ethyl acetate, 1-butanol, methyl ethyl ketone, m,p-xylene, o-xylene, 4-ethyltoluene, ethylbenzene, 3-ethyltoluene, and 1,2,4-trimethylbenzene. The main emission components in printing facilities were methyl ketone, ethyl acetate, acetone, 2-propanol, toluene, heptane, and butyl acetate. Ethyl acetate, toluene, 2-butanone, acetone, butyl acetate, 2-propanol, xylenes, and 4-methyl-2-pentanone were detected in the ambient air of the Pyeongdong industrial complex, consistent with the VOCs emitted by painting and printing facilities. The average concentration of seasonal TVOCs followed an order of winter > fall > spring > summer, whereas the concentrations of daytime and nighttime TVOCs were generally higher at night than those during the day, and the wind speed was greater during the day than it was at night. Based on a factor analysis of VOCs in the ambient air of Pyeongdong industrial complex, it is considered that organic solvents used in coating, printing, and electronics manufacturing facilities, as well as diesel vehicle emissions played a major role.