• Journal of computational fluids engineering
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• v.14 no.4
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• pp.62-66
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• 2009

The control of particle concentration distribution in a pipe with an orifice and a sheath air is numerically investigated. When using Eulerian approach, there is no great change in the concentration distribution by the shape of orifice and molecular diffusivity. As the Reynolds number becomes small, the effect of orifice on the concentration distribution is decreased. For small Reynolds number, the concentration distribution can be effectively controlled by using a sheath air. The effect of the sheath air on the concentration distribution is increased, as the Reynolds number becomes small.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.12-21
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• 2012

The purpose of this study is to understand distribution of ozone concentration in the south coastal region of Korea by evaluating ozone spatial distribution in the upper air using aircraft. Sampling was carried out from May to August in 2009. The average concentration of ozone in the upper air was ranged from 32.3~90.8 ppb with its maximum concentration of 132 ppb. When it comes to the spatial distribution of ozone, ambient concentration was high in the air, 1,000 m and 500 m above the southern sea near the Gwangyang Bay area and emission sources, respectively. Daily mean concentration of NOy was 6.7~24.2 ppb and that of CO was 0.152~0.487 ppm. In addition, the concentration was appeared to be relatively high in the upper air of industrial regions and the southern seas. Meanwhile, the concentration of both $NO_y$ and CO was high in the upper air of the emission sources regardless of latitude. As for PAN, its daily mean concentration ranged between 0.1 and 0.6 ppb with overall mean concentration of 0.2 ppb. The average concentration of VOCs was 48 ppb, and the concentration of toluene and m,p-Xylene were higher than other components.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1243-1252
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• 2002

This paper aims to find the characteristics of concentration distribution of coastal urban air pollutants. For this purpose, It was used the daily meteorological data and the hourly concentration data for $O_3$and NO$_2$ in Busan metropolitan city from 1994 to 1996. It was investigated the annual and monthly distribution of ozone and nitrogen dioxide concentration at each site in Busan, and also investigated the characteristics of concentration change of air pollutants with time under the sea breeze. As a results, the concentration of nitrogen dioxide and ozone tend to be increased every year and nitrogen dioxide concentration is higher than ozone concentration at all sites in Busan. The concentration of ozone is high in summer season and low in winter season, but the concentration of nitrogen dioxide have a reversed trend. The monthly peak concentration of ozone occurred in April and September, while the monthly minimum concentration of nitrogen dioxide occurred in August. Their trend were identified by sites near the coastline than sites stands apart from the coastline. The sea breeze occurred annual mean 81 day in Busan from 1994 to 1996. The main wind direction of sea breeze was classified into southwesterly and southeasterly. In case of southwesterly, It was pronounced the south wind and southwest wind. In case of southeasterly, the occurrence frequency of east wind was high. Especially, the concentrations of urban air pollutants, such as ozone and nitrogen dioxide, were high on time which the sea breeze flow, and the areas that ozone concentration was high moved from outside part to central part of city with time. In costal urban such as Busan, the wind direction of sea breeze is influenced the change of ozone and nitrogen dioxide concentration on time which the sea breeze flow at each site and also influenced the change of air pollutants concentration of sites on the pathway of sea breeze.

• KIEAE Journal
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• v.5 no.3
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• pp.41-48
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• 2005

Before occupation of an apartment housing, the builders are required to inform the test result of IAQ to the public. However, there is no simplified method to predict IAQ before measurement of pollutant concentration. In this study, a simplified way of predicting IAQ based on the distribution of indoor pollutant concentration is proposed. 7 different cases of air change rate have been simulated through CFD analysis to get the distribution ratio of each pollutant material and then simplified functions were used with CRIAQ1 values derived from CFD simulation to evaluate by comparing the influence of each material in the indoor pollutant concentration. Again, a lot of efforts which can improve the indoor air quality have been performed. Materials used in indoor space are labeled with their pollutant emission level. Installation of ventilation system in residential buildings will be regulated by a building codes sooner or later. But it is important to understand the fact that layout of walls, location or size of openings will influence the indoor air flow and pollutant concentration. And location of emitting material influences to indoor air pollutants distribution. But until now there is few recognition and consideration of these factors. Therefore, in this paper the effects of these factors is proved and some kind of guideline is made for designers after a comparison of typical apartment floor plan and a new type plan with their average pollutant concentration and its distribution of each room. CFD(Computational Fluid Dynamics) program was used to show the indoor air flow and pollutant concentration distribution. For this purpose, a typical $100m^2$ apartment floor plan was chosen as a case study model and several alternatives were reviewed to improve the IAQ performance. The simulation took place in the condition of natural ventilation through windows.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.281-286
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• 1999

This study was conduced to examine the monthly and seasonal variation of $SO_2$, TSP, $O_3$ concentration in Dongsamdong, Pusan coastal area. And the characteristics of air pollution of this area was compared to Kwangbokdong in Pusan and Taehadong in Ullungdo. Monthly mean concentration of $SO_2$ and TSP showed lower than Kwangbokdong, $O_3$ was higher than Kwangbokdong. In case of $SO_2$, seasonal variation of Dongsamdong was remarkabler thn Kwangbokdong and the concentration difference of early morning and daytime was higher than Kwangbokdong. Taehadong showed very lower concentration as background area. In case of TSP, Dongsamdong was lower concentration and smaller diurnal change than Kwangbokdong, Taehadong showed very lower concentration as backgound area. In case of $O_3$, Dongsamdong was 10ppb higher than Kwangbokdong at daytime maximum concentration, diurnal change of concentration was higher, too. In case of frequency distribution of concentration, $SO_2$, and TSP at Dongsamdong showed higher frequency in low concentration class and $O_3$ showed in high concentration class as compared with Kwangbokdong.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.1
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• pp.57-63
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• 1994

In order to comprehension of the behaviour of PAHs in air which is known as carcinogens and/or mutagens suspended Particulates in ambient air were collected by Anderson air sampler from 1992. 6 to 1993. 5 in Seoul. Ten species of PAHs( Phen, An, Fl, R, Py, BaAn, BaP, Chry, BeP, DiB(a, h)An, I123p) were analyzed to understand monthly variations of PAHs distribution of PAHs concentration according to particle size, and correlation between PAHs and independent charactierstics of PAHs The highest concentration of TSP was 155.58$\mu\textrm{g}$/㎥ in May and the lowest was 60$\mu\textrm{g}$/㎥ in August. Concentration of TSP was more affected by coarse particles in spring, otherwise which was more affected by fine particles in winter. According to results of anaylsis of samples that were collected by Anderson air sampler, concentration of PAHs was more high in winter than that in summer. In almost samples collected by Anderson air sampler, concentration of PAHs was more high in coarse particles than in fine particles, but BaP well known as carcinogenic matter had more high concentration in fine particles(56-97.5%) than that in coarse particles(2.5-46%). Correlation between concentrations of TSP and PAHs was more high in fine Particles than in coarse Particles. Both fine particles and coarse particles have negative correaltion with radiation.

• Journal of Environmental Science International
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• v.3 no.4
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• pp.357-365
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• 1994

Air pollution characteristics and the influence of sea breeze on air pollution concentration were studied using the data measured at 7 air quality continuous monitoring stations in Pusan, 1993. Maximum air pollution concentration in Pusan was Gamjeondong for $SO_2$, Sinpyeongdong for TSP, Daeyeondong for $O_3, Kwangbokdong for $NO_2$, Beomcheondong for CO and all substances were under annual ambient air quality standards. Increased rate of concentration for sea breeze was 24.4% for 502, 31.5% for TSP, 8.0% fort $O_3, 26.7% for $NO_2$, 15.7% for CO. Frequencies distribution of $SO_2$, TSP, $O_3$, $NO_2$, and CO concentration for sea breeze moved toward high concentration class.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.100-107
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• 2001

On the planning for the systematic management and control of the air pollution display methods were used to evaluate the spatial pollutant concentration status. This study were conducted to investigate the practical using of Geographic Information System(GIS) technology on the air pollution control and management which were computer-based systems that were used to store and manipulate geographic information in the macro city. In this study 137 samples were corrected by passive samplers and analysed by GC/MSD for 16 VOCs in Seoul (25 distincts) distributed by TM-coordinate(2 km$\times$2km), and finally displayed by Arciew program(version 3.2, ESRI Inc, USA) for windows. The concentration of benzene and toluene showed high level in whole area of seoul area of Seoul and distribution of butylbenzen, trothroloetylene, stylen showed high level in whole area of Seoul except a few distincts and the distribution of isopropylbenzene, 1,2-dichroloethane showed higher level in core area than that of Kangnam and Kangbuk area. In conclusion, products of this study of using GIS technology apply on the spatial distribution of VOCs concentration was very effective than that of other methods(e.g., contouring concentration method, pie or column chart, graduated symbols), especially in mapping and symbolization of pollution status evaluation.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.1
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• pp.33-39
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• 1990

This study has been conducted by experiments for distribution of concentration of helium gas, which is jetted into stationary atmosphere at the normal temperature and pressure. It is able to obtain the data for concentration of helium and air mixtures by the use of hot wire probe which has fast response. At an up stream, the concentration gradient which is attained is steep. At a down stream, the mixing time of helium and air is gradually shortened with the lapse of time in front of a jet. The arrival frequency of a jet in an unsteady area is mostly constant from 0% to 100% up to 80mm, but the time which is reaching to 100% is gradually to lengthen as a descending downstream. After starting a jet and the point of 90%, the mixing time is especially to lengthen. This reason comes from the turbulent intensity which causes for mixing of helium and air. This time difference which causes according to lengthen a jet should be considered in the design of combustion chamber.

• Journal of Environmental Health Sciences
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• v.22 no.3
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• pp.64-71
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• 1996

Measurement of concentration and size distribution of TSP, ammonium, nitrate and sulfate were made from Mar., 1991. to June., 1992 in Seoul. The seasonal variation of concentration and size distribution of aerosols has been investiated. Aerosol were collected and size frationated by Andersen air sampler. Size classified samples were extrated with deionized water and analyzed for ammonium, nitrate and sulfate by ion chromatography. As the results of measurement, the average of concentration and MMAD(mass median aerodynamic diameter) were $118.58 \mu g/m^3$, and $2.77 \mu m$ for TSP, $1.92 \mu g/m^3$ and $1.35 \mu m$ for ammonium, $1.34 \mu g/m^3$ and $1.58 \mu m$ for nitrate, $8.52 \mu g/m^3$ and $2.15 \mu m$ for sulfate. The Seasonal variation of concentration and size distribution was observed for ammonium, nitrate and sulfate. The concentration peak of TSP was observed in coarse particles in spring and observed in fine particles in winter. The concentration's distribution of TSP, ammonium, nitrate and sulfate was observed bimodal type during all season.