• Title/Summary/Keyword: Urban Environmental Problems

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A Study on Green Net-Work Construction for Urban Heat Island Mitigation in Dalseo District, Daegu Metropolitan City (도시열섬현상 저감을 위한 그린네트워크 구축 방안에 관한 연구 - 대구광역시 달서구를 대상으로 -)

  • Kim, Gi Ho;Kim, Su Bong;Jeong, Eung Ho
    • Journal of Environmental Science International
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    • v.13 no.6
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    • pp.527-535
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    • 2004
  • As urbanization has been expanded in Korea, open spaces, such as urban parks and public sites, have been utilized for other uses, and then this bring out environmental changes for the worse. It is expected that these changes become more serious problems due to overpopulation, increasing individualism, and development of transportation. This research base on the consideration of connecting between decreasing urban green spaces and distributed green sites so as to build the substantial plan for the Green Network construction for urban heat island mitigation in Dalseo district, Daegu Metropolitan City. The result were as follow; 1) Connecting existing natural sites to the remained parks green zone made an Ideal form of Green-Network system. 2) Some school sites were selected for usable open spaces in order to build Green-Network system, and the plan connecting together with exist natural sites was suggested. 3) Moreover, the scheme of planting on the road spaces for connecting green spaces was proposed. 4) The devices of planting on the urban riverside for enhancing the role of urban stream to form green network was conceived.

Study on the Noise-mapping Procedure in Korea and Application of Nosie map (국내의 소음지도 제작과 활용에 대한 연구)

  • Oh, Jin-Woo;Chang, Seo-Il;Lee, Ki-Jung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.778-781
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    • 2004
  • Recently, one of the reason of noise problems is urban planning has little concern about noise. For solving noise problems, strategic action is needed during urban planning. The noise map is one of the solution for concerning about noise in urban planning and EC has been studied the noise map for the strategic purpose since 1970s. The noise map is powerful tool for predicting sound level, calculating exposure population and evaluating the efficiency of the noise reduction plan. In Korea, The noise map is a unfamiliar field. The experience is few for noise-mapping and the noise mapping procedure has not been standardization yet. For activation of noise map, the study about fundamental problems of collecting data md noise-mapping procedure must be need. This paper is for studying on the noise-mapping procedure in Korea and application of noise map.

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Study on the Impacts of Lateral Boundary Conditions and Thermodynamics of Urban Park using Coupling System of WRF / ENVI-met (WRF / ENVI-met 통합모형을 적용한 도시 공원의 경계 조건 및 열역학적 영향 분석 연구)

  • Lee, Tae-Jin;Yoo, Jung-Woo;Lee, Hwawoon;Won, Hyo-sung;Lee, Soon-Hwan
    • Journal of Environmental Science International
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    • v.26 no.4
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    • pp.493-507
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    • 2017
  • Since the late 20th century, the urbanization in Korea has been rapidly increasing, especially in major cities like Seoul, as a result of industrialization. One of the aspects of urbanization is coating the surfaces with impervious concrete or asphalt that water cannot penetrate. In addition, various urban, such as urban heat islands, which also have a great impact on the urban environment, occur within the cities. Therefore, the urban environment is gradually becoming hot and dry, and the need for more urban parks to compensate for these negative impacts is growing. Thus, several numerical studies have been conducted to assess these problems using coupled Numerical Weather Prediction (NWP) and Computational Fluid Dynamics (CFD). In this study, an experiment was conducted to determine the accuracy of the area of the input field using Weather Research and Forecasting (WRF) model, and applying the more accurate input field to a numerical simulation using ENVI-met, in order to investigate the effect of urban parks on the thermal comfort. The results showed that an input field with a larger area is more accurate than that with a smaller area, because the surrounding terrain and cities are considered in details in the experiment with the larger area. Subsequently, the more accurate input field was used in ENVI-met, and the results of this simulation showed that the presence of the urban park increased the thermal comfort and improved the humidity conditions.

A Multiplex Housing Energy Conservation Strategy through Combining Insulation Standard Based Green Roof Systems and Passive Design Elements

  • Son, Hyeongmin;Park, Dong Yoon;Chang, Seongju
    • KIEAE Journal
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    • v.14 no.1
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    • pp.31-38
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    • 2014
  • Recently, the coverage of urban forests has been rapidly decreasing as the cities are created and expanding. Consequently, there arise urban problems such as heat island effect, urban flooding, urban desertification and so on. In this context, green roof systems is considered to be an efficient alternative to deal with these problems. However, it is difficult to apply green roof to new buildings since the majority of the buildings in cities are already constructed and the demand for new building constructions is not high enough. Therefore, it should be considered to apply green roof system to existing buildings for resolving various problems. This study evaluates heating and cooling energy consumption based on the combination of passive design factors such as wall, roof, window insulation in addition to a green roof system applied to an existing house by using an energy simulation program. Total 8 potential improvement cases are developed. Each case is applied to the same house with different insulation standard for simulations. Through the analysis of the simulated cases with the chosen test house, it is confirmed that heating energy consumption decreases as improvement cases are applied, but cooling energy consumption is relatively not much affected by each improvement case. In addition, when each improvement case is applied to already highly insulated house, the effect of thermal energy improvement decreases while the same improvement that is applied to the case with low insulated house tends to yield higher improvement rate.

A Simple Model for Dispersion in the Stable Boundary Layer

  • Kang Sung-Dae;Kimura Fujio;Lee Hwa-Woon;Kim Yoo-Keun
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.1 no.1
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    • pp.35-43
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    • 1997
  • Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are 'A' and 'B' at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.

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Wind Characteristics at Urban Stream - Case of Yangjae Stream at Gangnam-gu in Seoul - (도시하천의 바람 특성 - 서울 강남구 양재천을 대상으로 -)

  • Lee, Sang-Jeong;Lee, Won-Bo;Jin, Wen-Cheng;Lee, Kyoo-Seock
    • Journal of Environmental Impact Assessment
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    • v.21 no.1
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    • pp.201-208
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    • 2012
  • Global warming due to the climate change causes environmental problems such as urban heat island (UHI), air pollutant deposition, urban heavy rainfall, etc. Urban stream plays an important role on mitigating UHI as open space as well as an ecological corridor in urban area. In order to investigate the wind characteristics of urban stream in the case of Yangjae Stream at Daechi-dong, Gangnam-gu in Seoul, the wind direction and wind speed data were observed and analyzed using a propellor type RM-Young wind monitor. The results show that the prevailing wind direction was southwest. However, easterly wind is the prevailing one between 8:00 and 12:00. Strong wind whose Beaufort scale is four or more blew frequently from 12:00 to 18:00. In terms of seasonal frequency, the spring shows the highest frequency, then winter was the next.

The Investigation of Problems for Next Generation Energy System during Existing Urban Plan Stage (기존 도시계획 단계에서 차세대에너지시스템 적용시 문제점 검토)

  • Park, Jin-Young;Kim, Sam-Uel;Park, Yool;Lee, Sang-Jin;Lee, Jurng-Jae
    • 한국태양에너지학회:학술대회논문집
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    • 2009.04a
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    • pp.190-195
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    • 2009
  • Since the industrial revolution, the global environmental problems such as greenhouse gas accumulation and the average temperature increase have caused people's attention. 'Low Carbon, Green Growth' was presented to cope with these global concerns, as one of main policies of 2008 in Korea. The paradigm of a green urban development is started to concern the whole city's energy problems owing to realize 'Low Carbon, Green Growth' in the urban side. The government established a nation's basic energy plan for 20 years, and some local cities made efforts to develop new renewable energy such as the solar, wind and water energy which are suitable to each city's character. As a part of these efforts, the concept of U-Eco city is newly appeared to reflect upon ubiquitous technique, urban ecology and the next generation energy system. However, urban plan is difficult to adopt this next generation energy system with existing laws, regulations and technical systems. The new executive and systematic system is needed to realize the U-Eco city U-Eco for the management of an efficient city. In this study, the authors investigate the concept of the next generation energy system and U-Eco city to realize the energy-efficient city plan and analyze problems to occur during the application of them in an existing city plan. Then, the authors show the remedies to deal with occurred problems.

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Evaluation Method of Urban Development Location by APEI (Air Pollution Exposure Index) (대기오염 노출지표에 의한 도시개발 입지의 평가에 관한 연구)

  • Kim, Ki-Bum;Kwon, Woo-Taeg;Kim, Hyung-Chul
    • Journal of Environmental Impact Assessment
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    • v.16 no.4
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    • pp.267-275
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    • 2007
  • In this study, relationship between the air pollution of Siheung city and the relative contribution of automobiles to the city's pollution was evaluated for the first time. Then, new air pollution exposure index was developed through simulation. Using the newly developed index, two different urban development scenarios were compared to present a sustainable urban development plan to reduce air pollution from the land utilization point of view. According to the result of this simulation, air quality of the city was found to be affected significantly by human activities. More populated area showed worse level of air quality. Any development in the city resulted in more automobile activity and deterioration of air quality. This simulation result thus explains that a rapid increase of automobiles accompanied by the land development near local roadsides in the city is the major cause of air pollution in Siheung city. In this study, if urban activities are vigorous in an area with high air pollution, people are more likely to be exposed to air pollutant under the bad environmental conditions. On the other hand, if urban activities are less vigorous in an area with high pollution or if urban activities are vigorous in an area with less pollution, the environmental condition was positive. The APEI (Air Pollution Exposure Index) was developed based on these considerations. Scenarios 1 and 2 were compared and analyzed using APEI. In result, scenario 1 is the case in which land is developed and used in an environmentally favorable manner. From this study, it was proved that the impact of air pollution on human health can be minimized with proper land use. The result form the current study can be used as the basic information to solve problems from improper land utilization and air pollution (by road traffic). It also can be utilized to evaluate air pollution level according to land use and road characteristics and to help to choose the best location of land use to comply with the road function and status.

Habitat Types of Wintering Season Wildbirds Depending on Land Use, Hanam (하남시 토지이용현황에 따른 겨울철 야생조류 서식유형 분석 연구)

  • Kim, Jeong-Ho
    • Journal of Environmental Science International
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    • v.15 no.11
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    • pp.1077-1086
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    • 2006
  • This study aims at analyzing relationships between land use and habitat types of winter wildbirds to provide basic understanding of ecosystem for preservation and restoration of urban ecosystem in the future. The research area is Hanam City. Researches on land use types showed Hanam City had 79.1% of greenspace and openspace, but intensive urban development has been taking place in greenspace that is adjacent to urban districts. This has brought the problems of lack of greenspace in urban districts and damages to cultivated areas and grassland. A total of 61 and 8,642 populations of winter wildbird species were observed in research areas. Paradoxornis webbiann(16.91), Passer montanus(11.93), Pica pica(6.88) were dominant species. When they were divided according to habitat types, 20 species of interior species, 8 species of interior-edge generalist species, 12 species of edge species and 3 species of urban species were observed. When which land use type was mostly served as wildbirds habitats was examined, urban species(3 species and 290 populations) was a dominant species in urban districts while in greenspace and openspaece, water species(19species and 3,075 populations) including winter migratory birds was. Among greenspace and openspaece, edge species was dominant in forest while urban species was a dominant species in cultivated areas. This shows there is a need to improve diversity of wildbirds through restoration of cultivated areas in the central part of Hanam City.

Assessment of Water Circulation and Hydro-characteristics with LID techniques in urbanized areas (도시지역에 적용된 LID 기법의 강우시 수문특성 및 물순환 평가)

  • Choi, Hyeseon;Hong, Jungsun;Jeon, Minsu;Geronimo, Franz Kevin;Kim, Leehyung
    • Journal of Wetlands Research
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    • v.21 no.3
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    • pp.191-198
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    • 2019
  • High impervious surfaces increase the surface runoff during rainfall and reduces the underground infiltration thereby leading to water cycle distortion. The distortion of water cycle causes various urban environmental problems such as urban flooding, drought, water pollutant due to non-point pollution runoff, and water ecosystem damage. Climate change intensified seasonal biases in urban rainfall and affected urban microclimate, thereby increasing the intensity and frequency of urban floods and droughts. Low impact development(LID) technology has been applied to various purposes as a technique to reduce urban environmental problems caused by water by restoring the natural water cycle in the city. This study evaluated the contribution of hydrologic characteristics and water cycle recovery after LID application using long-term monitoring results of various LID technology applied in urban areas. Based on the results, the high retention and infiltration rate of the LID facility was found to contribute significantly to peak flow reduction and runoff delay during rainfall. The average runoff reduction effect was more than 60% at the LID facility. The surface area of the LID facility area ratio(SA/CA) was evaluated as an important factor affecting peak flow reduction and runoff delay effect.