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        검색결과 327

        281.
        2003.01 KCI 등재 서비스 종료(열람 제한)
        Urban air quality is usually worse than that of rural counterpart. The contrasting atmospheric properties seem to be direct result of different urban-rural air pollutant emission. Hence, the emission estimation of air pollutants plays an important role to the atmospheric environmental management. The main purpose of this study is to find out the temporal and spatial distribution of air pollutant emission in Daegu area. For the study, the Daegu statistical yearbook and data of waste facilities and the report on traffic survey issued by Daegu metropolitan city and the statistical yearbook on the road capacity issued by the ministry of construction and transportation are used. Each item for the emission estimation is SO2, CO, HC, NOx, PM-10 from point, line and area source. The result were as follow; (1) The air pollutants with the highest amount of emission from the emission source is CO fllowed by NOx, SO2, PM-10, HC in descending order of magnitude. (2) The annually totaled air pollutant emission consists of 81%(73,185 ton/year) of line, 11%(9,589% ton/year) of area and 8%(7,445 ton/year) of point source in Daegu. Air polluant emission was mainly due to line sources. (3) High-emission of the air pollutants of line source appeared ariond Bukgu, Dalseonggun, Dongu and Seogu ; the areas with highway networks.
        282.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        This study analyzes the surface ozone, NO and NO2 concentration data from 1997 to 1999 in Daegu. It investigates effect on precursor during high-ozone episode days. The high-ozone episode is defined when a daily maximum ozone concentration is higher than 100 ppb(ambient air quality standard of Korea) in at least one station among six air quality monitoring stations. The frequency of episodes is 13 days(33 hours). The frequency is the highest in May and September, and the area with the highest frequency is Nowondong and Manchondong. The average value of daily maximum ozone concentration with high ozone episode is 81.6 ppb, and that of 8-hour average ozone concentration is 58.6 ppb. It means that ozone pollution is continuous and wide-ranging in Daegu. The daily variation of NO, NO2 and O3 in high-ozone episodes are inversely proportional one another. Nowondong an industrial area, is affected by pollutants that are emitted from the primary sources, while Manchondong a residential area, is affected by the advection of O3 or by the primary pollutants like VOCs.
        283.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        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 O3 and NO2 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.
        285.
        2002.09 KCI 등재 서비스 종료(열람 제한)
        The recycled washwater, which has different water quality and is produced about 5 to 20% of the total water volume treated, affects the unit operation of water treatment, especially coagulation process. However, the effects of recycled washwater on unit operation of water treatment have not been fully investigated. In this study, effects of recycled washwater on coagulation process were investigated to find the optimum coagulation condition by analyzing turbidity, UV254, TOC removal efficiencies. In addition, effects of recycled washwater on residual Al after coagulation were studied by analyzing soluble and particulate Al. The size distribution and fractal dimension of coagulated also analyzed. The recycled washwater was lower pH than the raw water. And the recycled washwater had higher UV254, TOC and residual Al concentration than the raw water. Residual Al concentration of recycled washwater was about 50 times higher than that of raw water. Optimum coagulant dosages on the blending recycled washwater and the raw water for turbidity, UV254 and Al removal were lower than that on the raw water. However, TOC removal increased by increasing coagulant dosage. The size and fractal dimension of coagulated particle produced in the blending recycled washwater were larger, which imply faster settling velocity, than those produced in the raw water only.
        286.
        2002.09 KCI 등재 서비스 종료(열람 제한)
        The urban pollution if affected by local environmental, so it is necessary to consider area characteristics such as emission source and meteorological phenomena, in studying urban air pollution. Ulsan is laocated on south-east coast and has many industrial facilities, so many people have concerned about air pollution. This study contain conducting numerical simulation of air pollutant concentration considered land and sea breeze in Ulsan area with the numerical model.
        290.
        2001.12 KCI 등재 서비스 종료(열람 제한)
        A case of air pollution study of estimation of emission rate for source to railroad rolling stock and emissive character about is unusual. Recent emission rate of railroad rolling stock was estimated with emission factor of EPA in three region(Seoul, Incheon, and Gyeonggido). But this EPA factor could be incorrect because Korea and America have a different railroad environment in the variety of fuel and character of railroad rolling stock. In this study, emission rate of each line, car and region(district) with emission factor of Korean case(National Railroad Administration, 1997) was estimated. In Busan Metropolitan City, railroad rolling stocks were divided accoding to, each line, car and service. Particularly, the idle fuel rate omitted in the preceding study was included in calculation fuel rate. Total emission rate of Busan Metropolitan City was 887.41t/year. Each emission rates of Kyeongbu line, Donghaenambu line, Gaya line, Uam line, Bujeon line, and idle was 489.15t, 196.46t, 33.94t, 12.66t, 6.47t, and 148.72t, respectively.
        291.
        2001.10 KCI 등재 서비스 종료(열람 제한)
        To investigate air quality away from the coastal urban source region, we used a hybrid Eulerian-Lagrangian method which can describe the formation, transport, transformation and deposition processes in complex terrain. with inclusion of shipping sources that were considered to be important emission in the coastal urban region. The result of the Eulerian advection - diffusion prediction was quite similar to that of the Lagrangian particle diffusion prediction. It showed that pollutants emitted from piers can affect the part of inland, especially Dongrae and the coastal area. Those emitted from Sasang and Janglim industrial complexes can affect Hwamyeong and the coastal, respectively. During the daytime the concentration was low due to large deposition flux and terrain effect.
        293.
        2001.08 KCI 등재 서비스 종료(열람 제한)
        비보존성 오염물질의 종확산에 관한 단계분리 유한차분 모형을 낙동강에 적용하여, 1991년에 발생한 페놀누출 사고에 따른 종확산 모의계산을 수행하였다. Preissmann의 4점 음해법에 근거한 부정류 계산모형으로부터 산정된 계산결과를 종확산 모형의 입력자료로 사용하였다. 종확산계수의 산정을 위한 경험식 및 1차 반응의 감쇠계수에 따른 종확산 계산결과의 민감도를 분석하였다. 하류 지점에서의 첨두농도 발생 시각은 사용된 종확산계수 식에 따라 상당히 달라짐을
        294.
        2001.04 KCI 등재 서비스 종료(열람 제한)
        The atmospheric conditions and the transport mechanism of long-range transport of air pollutants from coastal area to inland area were investigated using regular meteorological data and air pollution data obtatined from the southeastern area of Korea. Daytime temperature over the inland area(Taegu) was higher than that over the coastal area(Pusan) and the temperature difference of about 5∼6℃ when the thermal low was most fully developed and the sea level pressure over Taegu was lower than that over Pusan by about 4∼5 hPa at that time. Therefore this low pressure appeared to the thermally induced low. Air mass polluted from the coastal area during the morning period was transported inland area, at first by the sea breeze and by the large scale wind system toward the thermal low generated in the mountainous inland region. This was explained by the fact that the concentration of air pollutants over Taegu increased throughtout the late afternoon.
        297.
        2000.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 금강유역전반에 걸친 수문 및 수질 현황을 조사 파악하였다. 또한 8회에 걸친 수질조사를 통하여 대청댐하류의 수질을 분석하였으며, 조사·분석된 자료를 바탕으로 일반수질항목에 대하여 기존의 수리·수질 모형을 개선하여 수질모의를 수행하였다. 또한 유해물질 유출사고시 조정지 댐에서의 적절한 방류시기를 결정하기 위한 주요지점에서의 도달시간을 산정하였다.
        300.
        2000.06 KCI 등재 서비스 종료(열람 제한)
        충남 서천군 춘장대에서 채취한 갯벌을 통수칼럼에넣고 오염물질 정화능력을 평가 해 보았다. 각 칼럼에 사용된 시료수는 하수를 G2여과지(6㎛)로 여과한 여액(R1), 생하수를 GF/C여과지(1.2㎛)로 여과 후 하수중의 미생물에 의한 영향을 제거하기 위하여 고압멸균기(autoclaver)로 120℃에서 15분간 멸균한 하수( R2), 여과·멸균된 하수를 membrane filter로 여과한 해수와 1:1(하수:해수)로 혼합한 시료수(R3) 그리고 R3에서 사용된 하수와 해수를 이용해 그 비를 1:2로 혼합한 시료수(R4)를 이용하였다. 4종류로 조제된 시험수를 이용한 통수실험 결과를 요약하면 다음과 같다. 통수실험에 의해 제거된 COD 양은 시료수에 하수의 함유량이 증가할수록 증가하였다. 암모니아질소의 경우 각 칼럼에서 580분 실험한 후 총 누적 제거양은 R1 90.1㎎, R2 81.0㎎, R3 27.6㎎, R4 4.1㎎이었다. R1과 R2에서 총 누적 제거 양이 해수가 1:1로 함유된 R3보다는 약 3배 높았고, 생하수와 해수가 1:2로 함유된 R4보다는 약 20배 높아 시료수에 하수의 함량이 높을수록 COD와 마찬가지로 암모니아질소가 잘 제거되는 것으로 판단되었다. 총인의 경우 각 칼럼에서 580분 실험한 수 제거된 총 누적 양은 R1 3.4㎎, R2 4.2㎎, R3 5.6㎎, R4 2.0㎎이었다. 평균 유입수 농도와 평균 유출수 농도로 구한 Pb의 평균 제거율은 R3와 R4에서 94.6%와 94.9%로 R1과 R2에서의 66.5%와 77.0%보다 약간 높았고, Cd의 평균 제거율도 R3와 R4에서 93.1%와 88.5%로 R1과 R2에서의 61.2%와 82.7%보다 약간 높았다. 이상과 같이 칼럼실험에서 중금속은 해수가 첨가된 시료에서 제거율이 높았다. 하지만 초기 20분간 흡착된 중금속의 양은 580분 동안 흡착된 총 양의 3∼4%로 유사한 값을 나타내었다.