• 한국환경보건학회지
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• 제33권5호
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• pp.372-378
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• 2007

This study evaluated formaldehyde concentration in classrooms and on roofs at 4 elementary schools, 3 middle schools and 3 high schools in Incheon City. These schools were chosen based on their surrounding environments that included industrial site, landfill, railway, 8-lane road and harbor. Indoor concentration ranged between 4.65 and $56.25{\mu}g/m^3$, while that of outdoor concentration was $1.23{\sim}10.22{\mu}g/m^3$, both of which were below $100{\mu}g/m^3$, a formaldehyde criterion stipulated by the School Health Act. Indoor concentration was higher than outdoor concentration by $1.4{\sim}5.9$ times, and there was a positive correlation between indoor and outdoor formaldehyde concentrations (R=0.49). As for indoor concentration, multi-use practice rooms had an average 2.8 times higher than that of usual classrooms with a statistically significant difference (p<0.01). Indoor formaldehyde concentration had a positive correlation with the construction year (R=0.55). The school close to the industrial complex had the highest ambient formaldehyde concentration, followed by the one near a landfill. The formaldehyde concentration in school in the vicinity of the industrial complex was twice or more than that of the school located other site. In conclusion, this study suggests that it is crucial to consider surrounding environments in selecting school sites, as it can influence ambient air contamination, as well as using construction material that emit less formaldehyde, in order to protect the health of students, teachers and school staff.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 추계학술대회 논문집
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• pp.439-440
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• 2003

대기질 모델(Air Quality Model)은 환경영향평가에서 필수적이다. 환경영향평가에 쓰이는 대기질 모델은 대부분 가우시안 플륨 모델이며, 그 중 ISC(Industrial Source Complex 3)이 가장 널리 쓰인다. 그러나 ISC3가 저풍속시 정확도가 떨어지지만 환경영향평가의 대기질 평가시 이에 대한 고려가 거의 이뤄지지 않은채 대기질 평가가 이뤄지고 있다. 본 연구에서는 ISCLT(Long Term)와 ISCST(Short Term) 모델에 대하여 입력되는 기상변수에 대한 민감도 분석을 수행함으로써 기상변수가 모델의 결과에 미치는 영향을 알아보고자 하였다. (중략)

• Asian Journal of Atmospheric Environment
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• 제10권4호
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• pp.208-216
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• 2016

This paper reports the results of a field evaluation which used sampling and analytical methods to determine the levels of airborne hexavalent chromium Cr(VI) in major industrial complexes in Korea over a seven year period (2007-2013). Cr(VI) concentrations were determined using cellulose filter sampling and ion chromatography analysis. In order to validate the analytical performance of these methods, studies were also carried out to investigate data quality control (QC) parameters, such as the method detection limit (MDL), repeatability, and recovery efficiencies. The average concentrations of Cr(VI) for the nine industrial complexes in Korea were in the range of 0.09 to $1.40ng/m^3$, which is similar to of the concentrations in other industrial areas around the world. The impacts of Cr(VI) emissions from industrial areas on Cr(VI) concentrations in neighboring-residential areas were considerably low, and the dispersion of Cr(VI) from industrial areas to residential areas was estimated to be 'not-significant'. Cr(VI) levels were not affected by seasonal variation, which suggests that chromium was emitted continuously from the industrial sources throughout the year. The concentration of Cr(VI) measured accounted for 0.7 to 9.4 percent of the total chromium level, which is a low percentage compared to those in other urban areas around the world. This is the first report in an international journal of a field study conducted in Korea to determine the concentration of Cr(VI) in the ambient air of industrial and residential areas.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3740-3747
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• 2009

경주 주변지역 시민들의 건강을 보호하고 보건 환경위해성 평가의 기초자료를 확보하기 위하여 기상학적 요소의 분포특성을 조사하고 RAMS 모델을 이용한 대기 유동장 수치모의를 수행하였다. 또한 대기오염물질 측정 및 분석과 ISC-AERMOD view를 이용한 대기오염물질의 거동을 예측하였으며 대기오염물질 관리를 통한 보건학적 피해 및 재산상의 피해를 예방하기 위한 보건 환경위해성 영향지역을 구분하였다. 경주 및 주변지역의 대기오염도를 조사한 결과 연평균 대기환경기준물질의 농도는 포항, 울산지역에 비해 약간 낮았으나 경주역 광장과 경주 용강사거리의 경우 미세먼지와 이산화질소 농도가 포항 및 울산지역 평균농도보다 높게 나타나는 경우도 발생하였다. 시민들의 건강에 영향을 미치는 대기오염물질의 이동 및 확산에 관한 모델링을 수행한 결과, 포항 철강공단지역은 POSCO와 함께 1공단과 2공단 및 3공단과 4공단 일부 지역이 미세먼지와 아황산가스 영향지역에 포함되었으며, 포항남구 해도동, 상대동, 제철동, 장흥동 등은 철강공업 및 대규모의 산업시설이 밀집되어 있어 다량의 대기오염물질이 배출되어 국지적인 대기환경질을 악화시키고 있는 것으로 나타났다.

• 한국대기환경학회지
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• 제22권4호
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• pp.421-430
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• 2006

This paper explores a new methodology of socio-statistical survey to classify environmental perception characteristics and to quantify atmospheric environmental sensitivity of neighboring people around a large industrial complex. In order to compensate intrinsic inclination against environmental problems, Atmospheric Environmental Sensitivity Index (AESI) is proposed as the weighted-summation of four representative questions asking the current status of the local air quality, which are chosen by the factor analysis of questionnaire. Atmospheric environmental perception is tried to be classified into interest/indifference characteristics and rational/emotional perception on environmental issues, positive/negative opinion on the solution of environmental problems. According to the chi-square cross-correlation and two-way layout analyses, it was clearly shown that environmental perception is categorized into two major groups, i.e., the positive-rational group having lower AESI and the negative-emotional group having higher AESI which means more seriously senses the status of local air quality.

• 한국대기환경학회지
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• 제25권4호
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• pp.275-288
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• 2009

The Korean government strengthened the environmental polices to manage and enhance Metropolitan Area air quality, and also has enforced "Special Act on Seoul Metropolitan Air Quality Improvement (SASMAQI)" issued in Dec. 2004. Recently government expanded the Seoul Metropolitan Air Quality Management District (SMAQMD) to the outskirts satellite cities of Seoul area through the "Revised Law Draft of SASMAQI". The SMAQMD has been alloted the allowable emission loads to the local governments on the basis of the carrying $PM_{10}$ capacity. However, in order to establish the effective air quality control strategy for $PM_{10}$, it is necessary to understand the corresponding sources which have a potential to directly impact ambient $PM_{10}$ concentration. To deal with the situations, many receptor methodologies have been developed to identify the origins of pollutants and to determine the contributions of sources of interests. The objective of this study was to extensively identify $PM_{10}$ sources and to estimate their contributions at the metropolitan area. $PM_{10}$ samples were simultaneously collected at the 3 semi-industrialized local cities in the Seoul metropolitan area such as Hwasung-si, Paju-si, and Icheon-si sites from April 15 to May 31, 2007. The samples collected on the teflon membrane filter by one $PM_{10}$ cyclone sampler were analyzed for trace metals and soluble ions and samples on the quartz fiber filter by another sampler were analyzed for OC and EC. Source apportionment study was then performed by using a positive matrix factorization (PMF) receptor model. A total of 6 sources were identified and their contributions were estimated in each monitoring site. Contribution results on Hwasung, Paju, and Icheon sites were as follows: 33%, 27%, and 27% from soil source, 26%, 26%, and 21% from secondary aerosol source, 11%, 11%, and 12% from biomass burning, 12%, 6%, and 5% from sea salt, 7%, 15%, and 19% from industrial related source, and finally 11%, 15%, and 16% from mobile and oil complex source, respectively. This study provides information on the major sources affecting air quality in the receptor sites and thus it will help to manage the ambient air quality in the metropolitan area by establishing reasonable control strategies, especially for the anthropogenic emission sources.

• 한국대기환경학회지
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• 제25권4호
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• pp.289-303
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• 2009

The chemical and meteorological effects on the concentration variations of ozone ($O_3$) were evaluated based on the intensive air quality measurement (5 pollutants and aromatic volatile organic compounds (AVOCs)) in and out-side an urban valley during spring and summer of 2006. The 5 pollutants measured in the study area include $O_3$, $NO_2$, NO, $PM_{10}$, and CO; the AVOCs include benzene (BEN), toluene (TOL), ethylbenzene (EB), m,p-xylene (MPX), and o-xylene (OX). For the purpose of this study, study areas were classified into two categories: valley area (VA) with a semi-closed topography covering a number of industrial complex, public building, and mountains and non-valley area (NVA) surrounding the suburban and residential areas. In general, the mean concentration levels of most pollutants (except for $PM_{10}$) in the VA were higher than those in the NVA. It was found that the average $O_3$ increase in the VA during spring might result from the combined effects such as the photochemical production from diverse anthropogenic sources and the $O_3$ accumulation due to geographical features (e.g., the semi-closed topography) and wind conditions (e.g., a low wind speed). In addition, the nocturnal $O_3$ increase in the VA during spring was primarily caused by local wind conditions (e.g., mountain and valley winds) with the low wind speed (approximately $1{\sim}2\;m\;s^{-1}$). On the other hand, the $O_3$ difference between the two areas during summer might be because of the photo-chemical production with the $O_3$ precursors (especially the AVOCs) rather than the contribution of wind conditions.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2003년도 춘계학술대회
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• pp.148-148
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• 2003

This study is to investigate the environmental levels and trend of dioxins, which was the 3$\^$rd/ year of environmental monitoring research for endocrine disrupting chemicals since 1999. Total 282 samples were analyzed from 115 sites including 26 sites of airs, 43 sites of waters, 11 sites of sediments and 35 sites of soil, which were the same as those of investigated sites in 2000. Sampling period was from June 2001 to June 2002. Target chemicals were seventeen species of 2,3,7,8-chlorine-substituted PCDD and PCDF congeners and were analyzed by the standard methods, established by National Institute Environmental Research (NIER). The average concentration of dioxins in air decreased from 0.324 pg-TEQ/N㎥ in 2000 to 0.287 pg-TEQ/N㎥ in 2001, and those in water and soil were 0.073pg-TEQ/L and 1.703pg-TEQ/dry g, respectively, which was the less values detected in 2000. In sediment, however, the value was 0.086pg-TEQ/dry g, which was the increase from the value of the year 2000. The concentration range of dioxins in air for 26 sites in 17 regions detected were 0.013∼l.664pg-TEQ/N㎥, 4 sites from those were exceeded the Air Quality Standards of Dioxin in Japan (0.6 pg-TEQ/N㎥). The tolerable daily intake of dioxins was calculated at the highest level (1.664) in air, with referring the soil and food data from Japan, was calculated to be 2.85pg-TEQ/kg/day, which was below the level of 4 pg-TEQ/kg/day suggested in KFDA(Korea). While the average concentration of dioxins in 15 big cities was 0.190 pg-TEQ/N㎥, that in 8 medium/small cities constituting an industrial complex was 0.558 pg-TEQ/N㎥. In water, the concentration range detected were 0∼0.946pg-TEQ/L and the trend of the average concentrations shows an increase from those of 1999 but decreased from those of 2000, any sites however were not exceeded the Water Quality Standards of Dioxin in Japan (1 pg- TEQ/L). In soil. the detected range were 0∼43.333 pg-TEQ/dry g and the average concentration decreased, compared with the results of 2000. According to the monitoring results by land utilization, the detected range were 0∼43.333pg-TEQ/dry g in farmland, 0.017∼0.601 pg-TEQ/dry g in the industrial area, 0.005∼0.049pg-TEQ/dry g in the park and 0.008∼1.825 pg-TEQ/dry g in the rest. In sediment, the detected range increased from 0∼0.244 pg-TEQ/dry g to 0∼0.537 pg-TEQ/dry g, based on the results of 2000. For the proper control of dioxins, continuous monitoring needs to be performed and in addition, the dioxin inventory should be prepared for major sources through the dioxin emission survey. These results would provide sound and solid basis for proper decision making of dioxins management like establishment of environmental quality standards in Korea.

• 산업경영시스템학회지
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• 제40권1호
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• pp.35-40
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• 2017

A most important progress in civilization was the introduction of mass production. One of main methods for mass production is die-casting molds. Due to the high velocity of the liquid metal, aluminum die-casting is so complex where flow momentum is critical matter in the mold filling process. Actually in complex parts, it is almost impossible to calculate the exact mold filling performance with using experimental knowledge. To manufacture the lightweight automobile bodies, aluminum die-castings play a definitive role in the automotive part industry. Due to this condition in the design procedure, the simulation is becoming more important. Simulation can make a casting system optimal and also elevate the casting quality with less experiment. The most advantage of using simulation programs is the time and cost saving of the casting layout design. For a die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize the casting layout design of an automotive Oil Pan_BR2E, Computer Aided Engineering (CAE) simulation was performed with three layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the filling process with three models, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflows. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system.

• 분석과학
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• 제20권1호
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• pp.33-40
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• 2007

대전시 3, 4 공단지역의 대기 중 미세분진을 대상으로 기기 중성자방사화분석법을 이용하여 유해금속을 포함한 약 27종의 미량원소를 분석하였다. 원소분석에 대한 정확도를 평가하기 위해 NIST SRM 2783(air particulate on filter media)을 사용하여 동일한 조건에서 분석한 결과, Sb, Mn, V, Mg, Na, K, Ti, Co, Zn, Sm은 상대오차 5% 이내의 매우 정확한 분석결과를 보였고 Cr, Fe, Ba, Th, Ce, Al, Cu는 10% 이내로 나타났다. 유해금속인 As, Mn, Se, V, Zn의 농도는 각각 $3.26{\pm}2.72$, $9.86{\pm}4.71$, $2.18{\pm}1.25$, $4.91{\pm}2.41$, $158{\pm}78ng/m^3$로 나타났고 인자분석 결과 연구대상지역의 미세분진에 대한 오염원은 6개로 추정되었다.