• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.71-85
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• 2012

The purpose of this study is to estimate air purification effectiveness considering the improvement of its methods related atmospheric environment. The air purification effectiveness is estimated in Daegu, one out of Korean Metropolitan cities because air pollution is getting serious in a heavily urbanized area. The absorption of pollutants is calculated by considering spatial heterogeneity that was not considered previous studies and the spatial resolution of air dispersion modeling is also improved by kriging method. According to the type and distribution of urban forest, total 26 kinds of plant communities were distributed with Pinus densiflora community, Pinus densiflora-Quercus mongolica community, Pinus densiflora-Quercus acutissima community and other kinds of communities in the study area. In the results of estimating the $CO_2$ absorption amount for identification of the air purification effectiveness on urban forest, the annual absorption amount was total 108,155t/yr. Also, the annual absorption amounts of $NO_2$ and $SO_2$ were total 183.5 ton and 410.2 ton respectively. The findings from this study can confirm the differences of pollutant absorption by concentration that could not identify if spatial distribution of pollutant concentration had not been considered.

• Journal of the Korean earth science society
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• v.25 no.6
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• pp.418-427
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• 2004

Recently, urban planning with consideration of urban climate, represented by the concept of urban ventilation lane is widely practiced in many countries. The concept of urban ventilation lane is mainly aimed to improve the thermal comfort within urban area in summer season. It has also the aim to reduce the urban air pollution by natural cold air drainage flows which are to be intensified by a suitable alignment of buildings as well as use zonings based on scientific reasons. In this study, the prevailing wind ventilation lane of a local wind circulation and around Daegu for a typical summer days was investigated by using a numerical simulation. The transport of air pollutants by the local circulation winds was also investigated by using the numerical simulation model, the RAMS (Reasonal Atmospheric Model System).The domain of interest is the vicinity of Daegu metropolitan city (about 900 km2). The horizontal scale of the area is about 30 km. The simulations were conducted under a late spring synoptic condition with weak gradient wind and almost clear sky. From the numerical experiment, the following three conclusions were obtained: (1) The major wind passages of the local circulation wind generated by radiative cooling over the representative mountains of Daegu (Mt. Palgong and Mt. Ap) were found. The winds blow down along the valley axis over the eastern part of Daegu as a gravity flow during nighttime. (2) At the flatland, the winds blow toward the western part of Daegu through the city center. (3) As the results, the air pollutants were transported toward the western part of Daegu by the winds during nighttime.

• Journal of Environmental Science International
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• v.17 no.4
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• pp.423-437
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• 2008

Until comparatively lately, the annual time series of the $SO_2$ concentration had been shown in a decreasing trend in Ulsan as well as other Korean cities. However, the high concentration of $SO_2$ was frequently found in the specific countermeasure region including the national industrial complex such as Mipo and Onsan in the Ulsan city for the period of $2001{\sim}2004$. There are many conditions that can influence the high concentration of $SO_2$ at monitoring sites in Ulsan, such as: First, annual usage of the fuel including sulfur increased in comparison with the year before in spite of the fuel conversion policy which wants to use low sulfur oil less than 3% and LNG. Second, point source, such as the power plants and the petroleum and chemistry stacks, was the biggest contributor in $SO_2$ emission, as a analyzed result of both the air quality modeling and the stack tole-monitoring system (TMS) data. And third, the air pollutants that occurred in processes of homing and manufacturing of the fuel including sulfur were transported slow into a special monitoring site by accumulating along the frontal area of see-breeze. It was concluded that Ulsan's current environmental policy together with control methods should be changed into the regulation on total amount of emission, including a market-based emission trading with calculating of atmospheric environmental critical loads, for the $SO_2$ reduction like the specific countermeasure for the $O_3$ and PM10 reduction in the Seoul metropolitan area. And this change should be started in the big point sources of $1{\sim}3$ species because they are big contributors of Ulsan's $SO_2$ pollution. Especially it is necessary to revitalize of the self-regulation environmental management. Other control methods for sustaining the $SO_2$ reduction are as follows: maintenance of the fuel conversion policy, reinforcement of the regional stationary source emission standard, and enlargement of the stack TMS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.8
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• pp.665-670
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• 2014

Because reducing atmospheric pollution is becoming a serious issue, studies are actively focusing on exhaust gas reduction. This study was conducted to determine the emission characteristics when applying an EGR system, the main approach used for NOx reduction, to an off-road mechanical diesel engine. For the application of the EGR system, the emission characteristics in consideration of the engine conditions were analyzed. The optimum EGR ratio for NOx emission reduction was determined by applying variable EGR conditions for each engine speed condition. Considering the above process, the emission characteristics of the modified EGR condition are compared with those of other conditions (non-EGR and existing EGR condition) in the NRTC mode. Consequently, NOx emission was reduced by around 42 compared with the non-EGR condition when using the modified EGR map.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3740-3747
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• 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 Conservation Science
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• v.33 no.3
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• pp.155-165
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• 2017

As interest in the public display of art and outdoor sculptures is increasing, the conservation and treatment of these sculptures is becoming increasingly crucial. Long-term exposure to the natural elements and atmospheric pollution can cause corrosion and deterioration in outdoor sculptures. In the case of Kim Chan Shik's "Feeling", which was exhibited in the outdoor sculpture park at the National Museum of Modern and Contemporary Art (MMCA), the patina of the sculpture was damaged during a long outdoor exhibition. Therefore, the treatment process was as follows: recording of condition, sanding, repatination, and wax coating. Consequently, the sculpture was restored similar to the original. Chemical analysis revealed that the sculpture was crafted from bronze and was cast from a quaternary alloy of Cu-Pb-Sn-Zn. The welding is lower in Zn, Sn, and Pb content than the metal used in the sculpture itself. Bright strains contain about 13.0 wt% Sn and 10.5 wt% Pb. The strains are higher in Sn and Pb content than the rest of the metal in the sculpture (7.0 wt% Sn and 4.4 wt% Pb). As a result of component analysis and microstructure observation, the material is estimated to have been made by casting without artificial treatment.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.335-335
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• 2001

Direct-normal, total horizontal and diffuse horizontal irradiance data obtained from a multi-filter rotating shadowband radiometer over seven different wavelength bands (416nm, 151nm, 616nm, 675nm, 870nm and 940nm and the entire spectrum) has been analyzed at Kwangju, South Korea from June 1998 December 2000. The maximum hourly global radiation flux ranged from 0.44 MJ/$m^2$ to 2.68 MJ/$m^2$ at around 11:00-12:00 Hr local time while the maximum hourly diffuse radiation flux ranged from about 0.96 MJ/$m^2$ to 1.37 MJ/$m^2$. The maximum hourly direct irradiance ranged from 1.42 MJ/$m^2$ to 2.92 MJ/$m^2$ from June1998-2000. During the period under consideration, the average monthly global radiation recorded were 13.09 MJ/$m^2$/day, 10.58MJ/$m^2$/day and 9.78MJ/$m^2$/day for years 1998, 1999 and 2000 respectively, while the diffuse irradiance were 6.54 MJ/$m^2$/day, 5.33 MJ/$m^2$/day and 5.14 MJ/$m^2$/day for f998, 1999 and 2000 respectively. The direct irradiance values at the site were 11.63 MJ/$m^2$/day, 8.24MJ/$m^2$/day and 7.75 MJ/$m^2$/day for 1998, f999 and 2000 respectively. It was observed that each of the years has its own unique meteorological parameters that affect the quality and quantity of radiation received for each month. The annual average daily fractions of the diffuse to the global radiation (KD) were 0.51, 0.61 and 0.59 for years 1998, 1999 and 2000 respectively. Analysis indicated that the average daily KD ranged from 0.13 to a maximum value of 0.99 in May for irradiance measured at the broadband channel while the maximum and minimum KD value of 0.91 and 0.23 was recorded at wavelength band 870nm and 940nm in January and September respectively. The lowest average daily clearness index (Kt) value recorded was 0.03 in May (Spring) and the annual average daily clearness indexes are 0.45, 0.34 and 0.35 for years 1998, f999 and 2000 respectively. The frequency of clear days annually at Kwangju is 67.95%, 29.57% and 40.72% for years 1998, 1999 and 2000 respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.4
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• pp.165-170
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• 2011

The ambient concentrations of nitrogen dioxide ($NO_2$) at 65 forest areas were measured every month using passive diffusive samplers from 2002 to 2009 and were compared to those at urban areas in order to investigate the characteristics of temporal and spatial distributions of $NO_2$ from the forest and urban areas. The annually averaged concentrations of $NO_2$ gradually decreased for both areas. The average concentration of $NO_2$ in the forest areas was 8.0 ppb, which was lower than that in the urban areas (i.e., 19.4 ppb) and the ecological standard level of the European Union (i.e., 14.6 ppb). The monthly average of $NO_2$ concentration depicted seasonal variations particularly in the urban areas, showing higher concentration in winter and lower concentration in summer. Strong locality of $NO_2$ concentration distribution illustrates that the locations near the metropolitan areas (e.g., Gyeonggi and Chungnam provinces) had the highest concentration during the measurement period. A significant positive correlation between $NO_x$ emissions and $NO_2$ concentration was observed, suggesting that the magnitude and proximity to sources of atmospheric nitrogen oxides would be important controlling factors.

• Atmosphere
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• v.21 no.1
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• pp.57-67
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• 2011

Aerosol lidar ratio (extinction-to-backscatter ratio) at 532 nm was determined using 4-year measurements of elastic-backscatter lidar and sky radiometer at Seoul National University of Seoul, Korea. The mean lidar ratio (with standard deviation) based on 4 years of measurements is found to be $61.7{\pm}16.5$ sr, and weak seasonal variations are noted with a maximum in JJA ($68.1{\pm}16.8$ sr) and a minimum in DJF ($57.2{\pm}17.9$ sr). The lidar ratios for clean, dust, and polluted conditions are estimated to be $45.0{\pm}9.5$ sr, $51.7{\pm}13.7$ sr, and $62.2{\pm}13.2$ sr, respectively. While the lidar ratio for the polluted condition is appears to be consistent with previous studies, clean and dust conditions tend to have larger ratios, compared to previous estimates. This discrepancy is thought to be mainly due to the anthropogenic aerosols existing throughout the year around Seoul, which may cause increased lidar ratios even for clean and dust conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.67-83
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• 2012

In order to evaluate die geochemical characteristics of sediment in a semi-enclosed bay used as shellfish and fish farming area, the concentrations of metallic(V, Cr, Mn, Fe, Co. Ni, Cu, Zn, Ag, Cd, Hg, Ph, As) and non-metallic(P, Se) elements and uranium were measured in the surface sediment samples collected from 19 stations of Gamak Bay in April 2010. Metal contamination status in the sediments were also evaluated using the sediment quality guidelines(SQGs) proposed by the National Oceanic and Atmospheric Administration(NOAA) and the enrichment factor(EF). The concentrations of elements in sediment were mainly controlled by quartz-dilution effect(V, Cr, Fe, Co and Ni), the dilution effect of organic matter(Cd and U), and metal redistribution by the decomposition of organic matter(Mn, Ag, As, and Se). The concentrations of metals, except As and Ni, in sediments from all sampling stations were lower than ERL values of NOAA. Conclusively, the surface sediment of Gamak Bay was slightly polluted with Ni, Ag, Cd, and Cd but was not polluted with other elements on the basis of EF results. Our results suggest that the surface sediment in Gamak Bay is not polluted by metallic elements.