• Journal of Environmental Health Sciences
• /
• v.33 no.5
• /
• pp.372-378
• /
• 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.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.11a
• /
• pp.439-440
• /
• 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
• /
• v.10 no.4
• /
• pp.208-216
• /
• 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.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.12
• /
• pp.3740-3747
• /
• 2009

To protect the citizens' health of Gyeongju and to secure basic data for the assessment of health and environmental risk, distribution characteristics of meteorological elements were investigated and numerical simulation of wind field using RAMS model was carried out. In addition, measurement and analysis of air pollutants, forecasting the behavior air pollutants using ISC-AEROMOD view, and health and environmental risk-influenced zones were defined through managing air polluting materials to prevent health damage and property damage. According to the survey results of air pollution in Gyeongju and surroundings, average annual concentration of air pollutants in Gyeongju was slightly lower than that in Pohang and Ulsan areas, but concentration of particulate matters and nitrogen dioxide at Gyeongju Station Square and Yonggang Crossing were sometimes higher than that in Pohang and Ulsan areas. Results of the modeling of moving and diffusion of air pollutants that affect citizens' health showed that parts of the 1st through 4th industrial complexes together with POSCO were included in particulate matters and sulfur dioxide influenced areas in Pohang Steel Complex area, and that Haedo-dong, Sangdae-dong, Jecheol-dong and Jangheung-dong in Pohangnam-gu represented locally worsened air quality due to a quantity of air pollutant emission from dense steel industries and large scale industrial facilities.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.4
• /
• pp.421-430
• /
• 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.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.4
• /
• pp.275-288
• /
• 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.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.4
• /
• pp.289-303
• /
• 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.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.05a
• /
• pp.148-148
• /
• 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.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.1
• /
• pp.35-40
• /
• 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.

• Analytical Science and Technology
• /
• v.20 no.1
• /
• pp.33-40
• /
• 2007

This study centered on the quantitative analysis of about 27 trace elements including toxic ones using instrumental neutron activation analysis of fine ambient particulate matter in the third and fourth industrial complex area of Daejeon city, Korea. For analytical quality control, the certified reference material (NIST, the National Institute of Standards and Technology, U.S.A., SRM 2783, air particulate on filter media) was used. The errors relative to SRM values of Sb, Mn, V, Mg, Na, K, Ti, Co, Zn, and Sm fell below 5%, while those of Cr, Fe, Ba, Th, Ce, Al, and Cu were less than 10%. From the results of the quantitative analysis, the concentration of toxic metals such as As, Mn, Se, V, and Zn were $3.26{\pm}2.72$, $9.86{\pm}4.71$, $2.18{\pm}1.25$, $4.91{\pm}2.41$, $158{\pm}78ng/m^3$, respectively. And the results of factor analysis indicated that there are no more than six factors of sources of fine ambient particulate with statistical significance in the study area.