• Journal of Environmental Impact Assessment
• /
• v.24 no.6
• /
• pp.578-592
• /
• 2015

To investigate characteristics and seasonal variations of carbonaceous species for $PM_{2.5}$ in Seoul metropolitan area, Korea, we measured organic carbon (OC) and elemental carbon (EC) from January 2014 to December 2014 using a semi-continuous OC/EC Analyzer (Model-4, Sunset Lab.). Mean concentrations of OC and EC were estimated $4.1{\pm}2.7{\mu}g/m^3$ and $1.6{\pm}1.0{\mu}g/m^3$, respectively. The annual averaged OC/EC ratio was $2.9{\pm}2.7$. Concentrations of OC and EC comprised 13% and 5% of $PM_{2.5}$ and the mass fraction of both was the highest in fall. OC and EC showed similar trend in seasonal variations. Concentrations of those showed a clear seasonal variation with the highest in winter and the lowest in summer. The correlations between the two were the best during the winter ($r^2=0.88$). As results of carbonaceous species analysis, the dominant factor in view of fine particle ($PM_{2.5}$) is primary emission source such as mobile, fossil fuel combustion during commute time(08:00~10:00 or 17:00~21:00) and winter season. Continuous monitoring of atmospheric carbonaceous species is essential to provide the science-based data to policy-maker establishing the air quality improvement policy.

• The Journal of Engineering Geology
• /
• v.16 no.4 s.50
• /
• pp.359-371
• /
• 2006

In this study, the soil characteristics are analyzed using the result of various soil tests as an object of the soil layer of natural slopes in landslides areas composed with gneiss, granite, and the tertiary sedimentary rock. To investigate the soil characteristics according to landslide and non landslide areas, soils are sampled from Jangheung, Sangju and Pohang. The landslides at three areas are occurred due to heavy rainfall in same time. The geology of Jangheung area, Sangju area and Pohang area is gneiss, granite, and the tertiary sedimentary rock, respectively. On the basis of the landslide data and the result of soil test, the soil characteristics at the landslide area and the differentiation between landslide area and non landslide area are analyzed. However soil characteristics have a little differentiation to geological condition, the uniformity coefficient and the coefficient of gradation of soils at the landslide area is larger than those of soils at the non landslide area. Also, the proportion of fine particle of soils at the landslide area is higher. The plastic limit of soils sampled from the granite and the sedimentary rock regions is larger than that sampled from the gneiss region. However the liquid limit is irrelevant to the geological condition. Also, the consistency of soils at the landslide area is smaller. The natural moisture content of soils in the sedimentary rock regions is larger than that of the granite and gneiss. It is mainly influenced by mineral composition, soil layer structure, weathering condition, and so on. The soils sampled from landslide area have higher porosity and lower density than those from non landslide area. It means that the soils of landslide area have poor particle size distribution and loose density. Therefore, the terrain slope with poor distribution and loose density is vulnerable to occur in landslides. Also, landslides are occurred in the terrain slope with high permeability. The permeability is mainly influenced by the soil characteristics such as particle size distribution, porosity, particle structure, and the geological origins such as weathering, sedimentary environment. Meanwhile, the shear strength of soils is little difference according to the geological condition. But, the internal friction angle of soils sampled from the landslide area is lower than that of soils from the non landslide area. Therefore, the terrain slope with low internal friction angle is more vulnerable to the landslide.

• Korean Journal of Remote Sensing
• /
• v.28 no.1
• /
• pp.11-19
• /
• 2012

Air-borne pollen, biogenically created aerosol particle, influences Earth's radiative balance, visibility impairment, and human health. The importance of pollens has resulted in numerous experimental studies aimed at characterizing their dispersion and transport, as well as health effects. There is, however, limited scientific information concerning the optical properties of airborne pollen particles contributing to total ambient aerosols. In this study, for the first time, optical characteristics of pollen such as aerosol backscattering coefficient, aerosol extinction coefficient, and depolarization ratio at 532 nm and their effect to the atmospheric aerosol were studied by lidar remotes sensing technique. Dual-Lidar observations were carried out at the Gwangju Institute of Science & Technology (GIST) located in Gwagnju, Korea ($35.15^{\circ}E$, $126.53^{\circ}N$) for a spring pollen event from 5 to 7 May 2009. The pollen concentration was measured at the rooftop of Gwangju Bohoon hospital where the building is located 1.0 km apart from lidar site by using Burkard trap sampler. During intensive observation period, high pollen concentration was detected as 1360, 2696, and $1952m^{-3}$ in 5, 6, and 7 May, and increased lidar return signal below 1.5km altitude. Pollen optical depth retrieved from depolarization ratio was 0.036, 0.021, and 0.019 in 5, 6, and 7 May, respectively. Pollen particles mainly detected in daytime resulting increased aerosol optical depth and decrease of Angstrom exponent.

• Economic and Environmental Geology
• /
• v.51 no.2
• /
• pp.87-97
• /
• 2018

The cesium (Cs) removal from the contaminated water system has been considered to be difficult because the cesium likes to exist as soluble phases such as ion and complexes than the solid in water system. Many researches have focused on developing the breakthrough adsorbent to increase the cesium removal efficiency in water. In this study, the laboratory scale experiments were performed to investigate the feasibility of the adsorption process using the bamboo charcoal for the Cs contaminated water system. The Cs removal efficiency of the bamboo charcoal were measured and the optimal adsorption conditions were determined by the adsorption batch experiments. Total 5 types of commercialized bamboo charcoals in Korea were used to identify their surface properties from SEM-EDS and XRD analyses and 3 types of bamboo charcoals having large specific surface areas were used for the adsorption batch experiment. The batch experiments to calculate the Cs removal efficiency were performed at conditions of various Cs concentration (0.01 - 10 mg/L), pH (3 - 11), temperature ($5-30^{\circ}C$), and adsorption time (10 - 120 min.). Experimental results were fitted to the Langmuir adsorption isotherm curve and their adsorption constants were determined to understand the adsorption properties of bamboo charcoal for Cs contaminated water system. From results of SEM-EDS analyses, the surfaces of bamboo charcoal particles were composed of typical fiber structures having various pores and dense lamella structures in supporting major adsorption spaces for Cs. From results of adsorption batch experiments, the Cs-133 removal efficiency of C type bamboo charcoal was the highest among those of 3 bamboo charcoal types and it was higher than 75 % (maximum of 82 %) even when the initial Cs concentration in water was lower than 1.0 mg/L, suggesting that the adsorption process using the bamboo charcoal has a great potential to remove Cs from the genuine Cs contaminated water, of which Cs concentration is low (< 1.0 mg/L) in general. The high Cs removal efficiency of bamboo charcoal was maintained in a relatively wide range of temperatures and pHs, supporting that the usage of the bamboo charcoal is feasible for various types of water. Experimental results were similar to the Langmuir adsorption model and the maximum amount of Cs adsorption (qm:mg/g) was 63.4 mg/g, which was higher than those of commercialized adsorbents used in previous studies. The surface coverage (${\theta}$) of bamboo charcoal was also maintained in low when the Cs concentration in water was < 1.0 mg/L, investigating that the Cs contaminated water can be remediated up with a small amount of bamboo charcoal.

• Journal of the Korean Geographical Society
• /
• v.29 no.3
• /
• pp.297-317
• /
• 1994

This study demonstrates the changes in the spatial organization of Korea by the construction of Seoul-Pusan railroad. This Seoul-Pusan line, which is the most important one in Korea was constructed in 1905. The original plan of the line was selected to cross the main traditional roads to control the entire Korean peninsular and to mobilize the Korean commercial potentials. It was the line to exploit the staples and to expand the Japanese market in Korea. In accordance with the contracts between Japan and Korean government, Korean government had to supply the lands for railroad, office, and service facilities. That was one of the important reasons that Korean government had been broken down. The main findings of this study are as follows: 1. The Seoul-Pusan railroad line was constructed Japanese colonial policy which emphasized three main purposes; the first was to reorganize the economic space and to collapse the traditional Korean markets for Japanese ruling, and the second was to find out the military supply routes, and the third was to search for the transcontinental line for China and Siberia. As the results, the old Korean pedestrian routes, which were the Eastern, the mid, the westren, and the Samnam route lost their functions. 2. Japanese requested for Korean government usually ten times of wider space for the site of stations than the needed one. The land was expropriated, and constructed the new centers aparted from the original Korean towns. In this process Japanese got the most developmental and windfall profits. The newly constructed centers were for Japanese immigration and the town service facilities which would be used to control the Korean financial market. At last, they easily converted the Korean spatial economy into Japanese colonial one, which made to reinforce the sphere of Seoul-Pusan line. 3. Japanese planned the stations as the central points in Korea. So the railroad stations were located apart from the centers of towns, to avoid the Korean resistances, and to maximize their profits. The mean distance from staiton to 'the town center is about 1km while the Japanese case is 0.6km. 4. The pattern of present Korean railroads is not the 'X type'. Because the Honam line is not the trunk one. So, we could call the Korean railroad pattern as the 'Ip(Chinese character 入) type' . The operational effects of Seoul-Pusan line brought out the concentration of the national economy to this line as Japanese planned. And the polorization had occurred between this line and the other parts of Korea. For twenty years (1910-1930), the transported freights were increased about 5 times. In 1930, the total freight of Seoul-Pusan line became 2, 010, 444 metric tons. If we examine this process, the underconstructing Seoul-Pusan express electric railroad should avoid adjacent this line to reduce the regional and ecological imbalance. 5. The forms of centers on the Seoul-Pusan line were classified into six types in relation to station, town center, and built-up area; the compact (integrated) type, the elongated one, the splited (independent) one, the absorbed one, the consolidated one, and the declined one. All types of these towns might be developed in accordance with the centrality, railroad function, and the other transportational functions. 6. The Seoul-Pusan line plays the most important role among Korean railroads but the ratio of passenger and freight become lower because the effiects of other inaugurated railoads the different transportation modes such as trucks and cars would be got more merits in competition. 7. The results of cluster analyses on the cities of railroad stations showed the rudimentary urban systems in 1910 and 1930. In 1930, the cities were classified into three groups; the group of small cites, the intermediate (developing) city-group, and the special city-group. In 1930s the spatial organization and urban system of Korea were similar to the present ones. We call appreciate that these were the effects of the Seoul-Pusan line.

• Journal of Conservation Science
• /
• v.34 no.5
• /
• pp.333-343
• /
• 2018

This study was conducted to evaluate the conservation environment by monitoring temperature and humidity for two years and mapping the remaining pigments of mural paintings to diagnose the conservation state of mural paintings of Royal Tombs in Neungsan-ri. We evaluated the characteristics of condensation in the tomb. Compared with the results of a 2008 survey, we conducted state change of mural paintings in the tomb. The temperature in the main room, which has an annual average soil temperature distribution at 5 m depth in Korea, is maintained at $13{\sim}18^{\circ}C$. The temperature range of the main room was between less than $0.1^{\circ}C$ to $0.5^{\circ}C$, and the diurnal variation of temperature between summer (June to September) and winter (December to January) is the greatest. Condensation is more concentrated in the summer because the outdoor air was typically at higher temperatures than the main room inflows in the tomb. Mapping the remaining pigment composition and particle distribution of mural paintings showed that it was in the range of 36.72~39.53% of the wall area. The pigment range was confirmed to be the same as it was in 2008, through ultraviolet fluorescence reaction and infrared ray investigation. Therefore, the underground environment that receives dew condensation in the summer has been stable since 2008. However, continuous monitoring is needed because the deterioration of mural painting proceeds considerably after excavation and only a small percentage of the pigments survive.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.7
• /
• pp.821-828
• /
• 2016

The water quality and phytoplankton presence in the ballast water (BW) of 37 vessels originating from the international ports of China were investigated to facilitate negotiations for exemptions to the Ballast Water Management Convention (BWM Convention). The shortest duration given BW spent in a vessel was $3.91{\pm}4.61days$ in area "A", which included the Bohai Sea. Total suspended solids, dissolved organic carbon, and particulate organic carbon ranged from 1.80 to $266mg\;L^{-1}$, from 1.09 to $5.79mg\;L^{-1}$, and from 0.17 to $3.65mg\;L^{-1}$, respectively. A low average concentration of nutrients was measured in BW from area "C", but the concentration of nutrients in BW from area "B" (around the Changjiang estuary) was high, which may be related to the relevant supply of freshwater. A high chlorophyll-a concentration (> $1{\mu}g\;L^{-1}$) was measured in six vessels, three of which carried BW in the area "A". High abundance of phytoplankton (> $10,000cells\;L^{-1}$) was measured in four vessels, two of which carried BW in the area "C". Vessel No. 37, originating from Hong Kong Bay in area "C", showed a high density of dinoflagellates. The results suggest that BWM Convention exemption negotiations with China should be performed cautiously.

• Korean Journal of Remote Sensing
• /
• v.20 no.2
• /
• pp.77-89
• /
• 2004

The spatial and temporal variations of aerosol optical depth (AOD) over Northeast Asia regions have special importance in the aerosol research for estimation of aerosol radiative forcing parameters and climate change. Aerosol optical and physical properties (AOD and ${\AA}$ngstrom parameter) have been investigated by using Moderate Resolution Imaging Spectroradiometer (MODIS) and Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI) to estimate aerosol characteristics over the study region during 2001. Additionally, aerosol characteristics over the Korean peninsular during Aerosol Characteristic Experiment in Asia (ACE-Asia) Intensive Observation Period (IOP) have been investigated by using satellite observations. The results showed that the daily-observed aerosol data indicate seasonal variations with relatively higher aerosol loading in the spring and very low during the winter. The typical Asian dust case showed higher AOD (>0.7) with lower Angstrom exponent (<0.5) and higher AI (>0.5) that is mainly due to the composition of coarse particles in the springtime. Mean AOD for 2001 at 4 different places showed 0.65$\pm$0.37 at Beijing, 0.31$\pm$0.19 at Gosan, 0.54$\pm$0.26 at Seoul, and 0.38$\pm$0.19 at Kwangju, respectively. An interesting result was found in the present study that polluted aerosol events with small size dominated-aerosol loading around the Korean peninsular are sometimes observed. The origin of these polluted aerosols was thought to East China. Aerosol distribution from satellite images and trajectory results shows the proof of aerosol transport. Therefore, aerosol monitoring using satellite data is very useful.

• The Korean Journal of Quaternary Research
• /
• v.14 no.1
• /
• pp.7-31
• /
• 2000

Quaternary Geological and geophysical investigation was performed at the Eurimji reservoir of Jaechon City in order to interprete depositional environment and genesis of lake sediments. For this purpose, echo sounding, bottom sampling and columnar sampling by drilling on board and GPR survey were employed for a proper field investigation. Laboratory tests cover grain size population analysis, pollen analysis and $^{14}C$ datings for the lake sediments. The some parts of lake bottom sediments anthropogenically tubated and filled several times to date, indicating several mounds on the bottom surface which is difficult to explain by bottom current. Majority of natural sediments were accumulated both as rolling and suspended loads during seasonal flooding regime, when flash flow and current flow are relatively strong not only at bridge area of the western part of Eurimji, connected to stream valley, but at the several conduit or sewage system surrounding the lake. Most of uniform suspend sediments are accumulated at the lake center and lower bank area. Some parts of bottom sediments indicate the existence of turbid flow and mudflow probably due to piezometric overflowing from the lake bottom, the existence of which are proved by CM patterns of the lake bottom sediments. The columnar samples of the lake sediments in ER-1 and ER-3-1 boreholes indicate good condition without any human tubation. The grain size character of borehole samples shows poorly sorted population, predominantly composed of fine sand and muds, varying skewness and kurtosis, which indicate multi-processed lake deposits, very similar to lake bottom sediments. Borehole columnar section, echo sounding and GPR survey profilings, as well as processed data, indicate that organic mud layers of Eurimji lake deposits are deeper and thicker towards lower bank area, especially west of profile line-9. In addition the columnar sediments indicate plant coverage of the Eurimji area were divided into two pollen zones. Arboreal pollen ( AP) is predominant in the lower pollen zone, whreas non-aboreal pollen(NAP) is rich in the upper pollen zone. Both of the pollen zones are related to the vegetation coverage frequently found in coniferous and deciduous broad-leaved trees(mixed forest) surrounded by mountains and hilly areas and prevailing by aquatic or aquatic margin under the wet temperate climate. The $^{14}C$ age of the dark gray organic muds, ER1-12 sample, is 950$\pm$40 years B.P. As the sediments are anthropogenetically undisturbed, it is assumed that the reliability of age is high. Three $^{14}C$ ages of the dark gray organic muds, including ER3-1-8, ER3-1-10, ER3-1-11 samples, are 600$\pm$30 years B.P., 650$\pm$30 years B.P., 800$\pm$40 years B.P. in the descending order of stratigraphic columnar section. Based on the interpretation of depositional environments and formation ages, it is proved that Eurimji reservoir were constructed at least 950$\pm$40 years B.P., the calibrated ages of which ranges from 827 years, B.P. to 866 years B.P. Ancient people utilize the natural environment of the stream valley to meet the need of water irrigation for agriculture in the local valley center and old alluvium fan area.