• 한국대기환경학회지
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• 제32권1호
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• pp.9-20
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• 2016

Ozone has been a problem in big cities. That is secondary air pollutant produced by nitrogen oxide and VOCs in the atmosphere. In order to solve this, the first to be the analysis of the $NO_x$ and VOCs. The main source of nitrogen oxide is the road mobile. Industrial sources in Seoul are particularly low, and mobile traffics on roads are large, so 45% of total $NO_x$ are estimated that road mobile emissions in Seoul. Thus, it is necessary to clarify the relation with the activity of road mobile source and $NO_x$ concentration. In this study, we analyzed the 4 locations with roadside automatic monitoring systems in their center. The V.K.T. calculating areas are set in circles with 50 meter spacing, 50 meter to 500 meter from their center. We assumed the total V.K.T. in the set radius affect the $NO_x$ concentration in the center. We used the hourly $NO_x$ concentrations data for the 4 observation points in July for the interference of the other sources are minimized. We used the intersection traffic survey data of all direction for construction of the V.K.T. data, the mobile activities on the roads. ArcGIS application was used for calculating the length of roads in the set radius. The V.K.T. data are multiplied by segment traffic volume and length of roads. As a result, the $NO_x$ concentration can be expressed as linear function formula for V.K.T. with high predictive power. Moreover we separated background concentration and concentrations due to road mobile source. These results can be used for forecasting the effect of traffic demand management plan.

• 한국조경학회지
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• 제29권3호
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• pp.38-45
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• 2001

This study quantified annual $CO_2$, SO$_2$ and NO$_2$ uptake and annual $O_2$ production by trees in Yongin´s urban ecosystem, and explored values of urban tree plantings in atmospheric purification. Woody plant cover was only 7.7% with planting density of 1. trees/100$m^2$, and the tree-age structure was largely characterized by a young, growing tree population. Annual per capita pollutant emissions from fossil fuel consumption were 7.3t/yr for $CO_2$, 7.6kg/yr for SO$_2$, and 26.6kg/yr for NO$_{x}$. Carbon dioxide storage per unit urban area by trees was 13.1t/ha and the economic value for $CO_2$ storage was ￦6.6millions/ha. Annual atmospheric purification was 2.0t/ha/yr for $CO_2$ uptake, 2.0kg/ha/yr for SO$_2$ uptake, 4.0kg/ha/yr for NO$_2$ uptake and 1.5t/ha/yr for $O_2$ production, and the annual economic value for the atmospheric purification was ￦1.5millions/ha/yr. Urbantrees stored an amount of $CO_2$ equivalent to about 3.1% of the total annual $CO_2$ emissions, and annually offset total $CO_2$ emissions by 0.5%. Annual SO$_2$ and NO$_2$ uptake by trees equaled 0.5% of total SO$_2$ emissions and 0.3% of total NO$_{x}$ emissions, respectively. Urban trees also played an important role through producing annually 9.2 of the $O_2$ requirement for Yongin´s total population, despite relatively poor tree plantings. Future active plantings and greenspace enlargement in the study city could enhance the role of atmospheric purification by urban trees. The results from this study are expected to be useful in emphasizing environment benefits of urban trees, and in urging the continuous necessity for tree planting and management budget.get.

• 환경영향평가
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• 제21권4호
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• pp.543-552
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• 2012

Namgang mid-watershed is located in downstream of Nakdong river basin. There are many pollution sources arround this area and it's control is important to manage a water quality of Nakdong river. A target year of Namgang mid-watershed water environment management plan is 2013. To predict a water quality at downstream of Namgang, we have investigated and forecasted the pollutant source and it's loading. There are some plan to construction the sewage treatment plants to improve the water quality of Nam river. Those are considered on predicting water quality. As results, it is shown that the population is 343,326 and sewerage supply rate is 79.2% and the livestock is 1,662,000 in Namgang mid-watershed. It is estimated that the population is 333,980, the sewerage supply rate is 86.9% in 2013. The milk cow and cattle were estimated upward and the pigs were downward by 2013. The generated loading of BOD and TP is 75,957 kg/day and 4,311 kg/day, discharged loading is 18,481 kg/day and 988 kg/day respectively in 2006. It were predicted upward the discharged loading of BOD and TP by 4.08% and 6.3% respectively. The results of water quality prediction of Namgang4 site were 2.5 mg/L of BOD and 0.120 mg/L of TP in 2013. It is over the target water quality at that site in 2015 about 25.0% and 9.1% respectively. Consequently, there need another counterplan to reduce the pollutants in that mid-watershed.

• 한국물환경학회지
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• 제28권6호
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• pp.804-812
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• 2012

This study contemplated domestic and other country's effluent limitation standards and suggested a methodology to establish technology-base limitation value. Current effluent limitation regulates industrial point sources discriminated by discharge flow rate and by regional distinction in Korea. Discharged $BOD_5$ load from large-scale plants(flow rate above $2,000\;m^3/day)$ exceeds 50% of overall industrial wastewater, which present rationale for discrimination based on plant size. However, regional distinction and pollutant- specific regulation might be insufficient to meet practical effectiveness of wastewater management policy, due to the nearly same limitation. Water quality data and treatment methods were investigated in hospital industry. And their distribution of effluent $BOD_5$ concentrations was statistically analyzed to suggest limitation value. Effluent $BOD_5$ concentrations showed lognormal distribution and $95^{th}$ percentile was corresponded to 87.9 mg/L, which could be suggested as tentative effluent limitation in hospital industry. The $95^{th}$ percentile of log-transformed distribution showed similar value of 86.5 mg/L. This study demonstrated reasonable methodology for establishing effluent limitation reflecting wastewater characteristic and treatment technology in separately categorized industry.

• 한국물환경학회지
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• 제25권6호
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• pp.849-854
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• 2009

Pollutant unit load (unit-load) reported by Ministry of Environment (MOE) in 1995 has been a useful method for watershed management and environmental policy decision. The unit-load has been estimated using effective rainfall ratio method. However, reliability of unit-load determined by the method has been criticized especially for paddy field and upland conditions. In this paper the unit-load of paddy field estimated by effective rainfall ratio method was compared with continuous monitoring data. Annual loads was simulated by the method choosing 5~6 storm events randomly from whole events collected. Probability distribution of difference between results by the method and measured data was investigated. The results showed that unit-load derived by the method was generally lesser than measured unit-load and showed wide variations. Therefore, unit-load estimation of paddy fields by effective rainfall ratio method need caution.

• 상하수도학회지
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• 제27권6호
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• pp.761-770
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• 2013

This study was carried out to forecast the flow rate and water quality at the inlet of the Saemangeum bay in Korea using the SWMM(Storm Water Management Model) and the WASP(Water Analysis Simulation Program), and to analyze the impacts of pollutant loading from non-point source on the water quality of the bay. The calibration and validation of flow rate and water quality were performed using those from two monitoring points in the Mankyeong river administrated by Korean Ministry of Environment as part of the national water quality monitoring network. When the river flow rate was calibrated and validated using the rainfall intensities during 2011-2012, $R^2$ (i.e., coefficient of determination) was ranged from 0.91 to 0.96. For water qualities, it was shown that $R^2$ of BOD(Biochemical Oxygen Demand) was ranged from 0.56 to 0.86, and $R^2$ of T-N(Total Nitrogen) was from 0.64 to 0.75, and $R^2$ of T-P(Total Phosphorus) was from 0.67 to 0.89. The integrated modeling system showed significant advances in the accuracy to estimate the water quality. Finally, further simulations showed that annual average flow of the river running into the bay was estimated to be $1.439{\times}10^9m^3/year$. The discharged load of BOD, T-N, and T-P into the bay were anticipated to be 618.7 ton/year, 331.5 ton/year, and 40.4 ton/year, respectively.

• 한국농공학회논문집
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• 제57권5호
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• pp.129-137
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• 2015

The objective of this study was to test the non-point source pollution (NPS) control by the vegetated ridge and silt fence through field monitoring. The experiment plots were established with three sizes which are 5 m width by 22 m length with 8 %, 3 % slope and 15m width by 15 m length with 6 % slope. Flumes with the floating type stage gages were installed at the outlet of each plot to monitor the runoff. For a rainfall monitoring, tipping bucket rain gage was installed within the experiment site. Water quality samples were monitored during the heavy rainfall occurred. The amount of rainfall from 4 monitored events ranged from 27.6 mm to 130 mm. The runoff reduction rate could vary depending on slope, soil, crop growth condition, rainfall amount, rainfall intensity, antecedent moisture condition, and many other factors. The runoff from vegetated ridge and silt fence treatment plots was 24.05 % and -8.28 % lower than that from control plot, respectively. The monitoring results showed that the average pollution loads reduced by vegetated ridge compared to control were BOD 36.62~53.60 %, SS 40.41~73.71 %, COD 39.34~56.41 %, DOC 49.08~53.67 %, TN 26.74~67.23 %, and TP 52.72~91.80 %; by silt fence compared to control were SS 41.73 %, COD 1.93 %, and TN 2.38 %. The paired t-test result indicated that the vegetated ridge and silt fence were statistically significant effect in SS load reduction, with a 5 % significant level. Monitored results indicated that vegetated ridge and silt fence were both effective to reduce the pollutant from the field surface runoff.

• 한국물환경학회지
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• 제20권5호
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• pp.422-431
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• 2004

Water quality modeling was performed for the purpose of diagnosis and prediction of water quality in Gyoung Choen reservoir, using EUTR05/WASP Build model. WASP Builder is capable of visual display in window and it has an advantage of updating and modification for data. Field data of 1992, Spring, Summer, and Fall, were used to calibrate model and these results were validated using data of 2000, Spring, Summer, and Fall. The reservoir was divided into 4 epilimnion segments. Water quality system for modeling were consist of BOD, Chlorophyll-a, DO, $NH_3-N$, $NO_3-N$, T-N, $PO_4-P$, T-P. The results of water quality modelling using EUTR05/WASP Builder, a range of the Correlation for calibration of BOD, T-N, T-P, and Chlorophyll-a according to three seasons are 0.63~0.90, 0.81~0.97, 0.75~0.98, and 0.77~0.98 respectively. And the correlation between simulated and observed values for verification of BOD, T-N, T-P, and Chlorophyll-a according to three seasons are 0.93, 0.94, 0.81, and 0.80 respectively. Among the pollutant sources for a basin of the Gyoung Choen reservoir, generated amount of livestock is the highest and BOD, T-N, T-P of generated loading percentage are 94%, 81%, and 95%. So, we suppose that inflow load amount will decrease 50% and increase 50% only livestock about current load amount. If increasing load amount of livestock 50% in segment 2 and 3, BOD, T-N, and T-P simulated increasing to range of $0.02~0.15mg/{\ell}$, $0.029~0.08mg/{\ell}$, $0.011~0.029mg/{\ell}$ in comparison with current water quality

• International Journal of Automotive Technology
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• 제4권2호
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• pp.65-75
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• 2003

A HEV evaluation program, funded by ADEME, was carried out by a group of Laboratories of different specialties in order to evaluate and compare consumption, emission and component technologies of the three first HEVs put on the market (Toyota Prius, Nissan Tino and Honda Insight). This paper presents the results obtained until now. These results show good consumption and emission performance of the tested vehicles compared to conventional ones. The energy management seems to be globally the same for the three vehicles excepting for cold stans where the Insight allows a very earlier stop of the engine compared to the Tino and especially to the Prius. A mapping of the engine consumption of the Prius and the Insight was performed in order to furnish data for the simulation models. The Permanent Magnet motors of the Prius and Tino have different number of pair poles and then different emf at a given speed. The low emf values of the Prius allow operation at high speed with less field weakening control than for the Tino. The inverters of the Prius and the Tino, controlled by a PWM at respectively 5 kHz and 7 kHz switching frequency, are made of IGBTs with high commutation performances.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.241-246
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• 2005

Doam watershed is located at alpine areas in the Kangwon province. The annual average precipitation, including snow accumulation during the winter, at the Doam watershed is significantly higher than other areas. Thus, pollutant laden runoff and sediment discharge from the alpine agricultural fields are causing water quality degradation at the Doam watershed. To estimate soil erosion from the agricultural fields, the Universal Soil Loss Equation (USLE) has been widely used because of its simplicity to use. The USLE rainfall erosivity (R) factor is responsible for impacts of rainfall on soil erosion. Thus, use of constant R factor for the Doam watershed cannot reflect variations in precipitation patterns, consequently soil erosion estimation. In the early spring at the Doam watershed, the stream flow increases because of snow melt, which results in erosion of loosened soil experiencing freezing and thaw during the winter. However, the USLE model cannot consider the impacts on soil erosion of freezing and thaw of the soil. Also, it cannot simulate temporal changes in USLE input parameters. Thus, the Soil and Water Assessment Tool (SWAT) model was investigated for its applicability to estimate soil erosion at the Doam watershed, instead of the widely used USLE model. The SWAT hydrology and erosion/sediment components were validated after calibration of the hydrologic component. The $R^2$ and Nash-Sutcliffe coefficient values are higher enough, thus it was found the SWAT model can be efficiently used to simulate hydrology and sediment yield at the Doam watershed. The effects of snow melt on SWAT estimated stream flow and sediment were investigated using long-term precipitation and temperature data at the Doam watershed. It was found significant amount of flow and sediment in the spring are contributed by melting snow accumulated during the winter. Thus, it is recommend that the SWAT model capable of simulating snow melt and long-term weather data needs to be used in estimating soil erosion at alpine agricultural land instead of the USLE model for successful soil erosion management at the Doam watershed.