• Journal of Korean Society for Atmospheric Environment
• /
• v.12 no.1
• /
• pp.67-77
• /
• 1996

Total suspended particulate matters (TSP) were collected based on a size segregation method by a cascade impactor for 6 consecutive years (form Dec. 1989 to sep. 1994) in the Kyung Hee University-Suwon Campus, and 6 trace metals (Ca, Si, Fe, Pb, Cu, Zn) were determined by an x-ray fluorescence spectroscopy. Total number of samples collected during the study are 118 sets and each set of sample comsists of 9 filters. The levels of TSP and 6 trace metals were then used to examine seasonal and annual variations with respects to their size distributions. For statistical analyses, raw data were initially transformed by both logarithmic and root transformating to approximately normalize them, and then size distribution functions for each trace element were separately developed season-to-season by a regression analysis in order to obtain maximum amount of physical information, Subsequently, each developed model was verified by comparing with supervised data collected on 1994. The result showed that each prediction model was in good agreement except the fall, partly due to lack of the data collected on fall, 1994.

• Journal of Hydrogen and New Energy
• /
• v.27 no.6
• /
• pp.747-752
• /
• 2016

Soot and harmful exhaust gas produced by liquid hydrocarbon fuel caused various environmental problems. In this study, soot characteristics produced by thermal decomposition of acetylene and diesel were analyzed, which are formed at different temperatures. These fuels were observed to produce particulate matters, and collected soot samples were observed by using TEM & SEM. These were found to be significantly different in structure and crystallinity.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.1138-1142
• /
• 2005

The IAQ management in subway cabin is very important for the enhancement of the amenity and health of passengers because the subway carries many passengers in a relatively short time mostly in urban area. However, since the ventilation of most subway cabins are performed by simple opening of doors at each stations, the IAQ management is not easy. In this study, we measured some IAQ factors (temperature, relative humidity, particulate matters, CO, and $CO_2$ concentration) of subway cabin in Seoul area. The results showed that the IAQ of the cabin was relatively acceptable. However, $CO_2$ concentrations were higher than 1,000 ppm in most cases. $CO_2$ concentration was mostly proportional to the number of passengers in cabin. Therefore, new method to relieve the $CO_2$ concentration is urgently required.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.1210-1213
• /
• 2006

Indoor air quality is an important determinant of human health and comfort. However, the complexity of pollution sources and the multitude of parties responsible for creating indoor exposures makes the improvement of air quality difficult. The KTX HVAC(Heating, Ventilating and Air-Conditioning) system is important facility to provide comfortable environment passenger service. The Ministry of Environment is planning to enforce$\square\square$Indoor Air Quality Management law in Public Facilities$\square\square$in year 2008. Hereupon, the train and the subway are included. In this research air quality in the KTX Train compartment has measured. As a result, The average amounts of PM10(particulate matters), $CO_2$(carbon dioxide)measured $20{\mu}g/m^3$, 1,097ppm in KTX respectively. There are compare to regulation the value is 10% for PM10 and 43% for $CO_2$. Thus, the indoor air quality of KTX train have been proved satisfy the recommendation the Ministry of Environment guidelines.

• Journal of Auto-vehicle Safety Association
• /
• v.6 no.1
• /
• pp.33-40
• /
• 2014

In this study the cylinder liner deformation which is one of the most influencing factors in a diesel engine oil consumption was performed by the finite element analysis on the basic designed structure consisting of the cylinder block, head and liners under the conditions of assembly, thermal and gas loads. Compared with a large number of other cylinder blocks showing remarkable harmonic orders of the liner distortion, results are excellent. Namely. the higher harmonic order amplitudes of the radial liner deformation amount to 1 ~ 2㎛ maximally. The main reason lies in the relatively large wall thickness of the liner which amounts to 8.2% of the bore diameter. Besides, a very stiff and symmetrical cylinder block design in combination with a bolt force introduction approximately 1.5mm below the block top deck have a further share on these results. Therefore excellent low oil consumption can be expected.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.1
• /
• pp.86-96
• /
• 2002

The distributions of suspended particulate matter (SPM), chlorophyll a, particulate organic carbon (POC) and nitrogen (PON) and particulate biogenic silica (PBSi) along the salinity gradient were investigated in the Seomjin River estuary from March 1999 to April 2001. Sampling sites were set based on the surface salinity during each cruise rather than geographic locations. Concentrations of SPM were less than 20 mg/L, suggesting relatively low input of terrestrial SPM despite large freshwater discharge through Seomiin River, Chlorophyll a peaks occurred at 5$\~$ 15 psu salinity zone (10$\~$20 km from Nan Cho Island) in November 1999, at 15$\~$25 psu (10$\~$20 km) salinity zone in April 2000 and at 1$\~$15 psu salinity zone (15$\~$20 km) in October 2000 (ca. 8$\~$58%\mu$g/L). Concentrations of POC, PON and PBSi were also high at the same zone. Relatively low ratios of POC to chlorophyll a in mid-salinity zone where POM peak occurred suggests high contribution of living phytoplankton to the total POC. On the other hand, relatively high ratios of POC to chlorophyll $\alpha$ in very low salinity zone and the mouth of estuary indicated relatively high portions of detrital POC. Consequently, the low concentrations of SPM in this estuary and the high concentrations of chlorophyll $\alpha$ and the low ratios of POC to chlorophyll $\alpha$ in the mid-salinity zone suggest that production of living phytoplankton is primary factor in controlling distribution of POM along the salinity gradients in the Seomjin River estuary.

• Particle and aerosol research
• /
• v.16 no.2
• /
• pp.31-47
• /
• 2020

Although interest in air quality has increased due to the frequent occurrence of high-concentration fine particulate matter recently, the official fine particulate matter measuring network has failed to provide spatial detailed air quality information. This is because current measurement equipment has a high cost of installation and maintenance, which limits the composition of the measuring network at high resolution. To compensate for the limitations of the current official measuring network, this study constructed a spatial high density measuring network using the fine particulate matter simple measuring device developed by Observer, W-Station. W-Station installed 48 units on Jeju Island and measured PM_2.5 for six months. The data collected in W-Station were corrected by applying the first regression equation for each section, and these measurements were compared and analyzed based on the official measurements installed in Jeju Island. As a result, the time series of PM_2.5 concentrations measured in W-Station showed concentration characteristics similar to those of the environmental pollution measuring network. In particular, the results of comparing the measurements of W-Station within a 2 km radius of the reference station and the reference station showed that the coefficient of determination (R²) was 0.79, 0.81, 0.67, respectively. In addition, for W-Station within a 1 km radius, the coefficient of determination was 0.85, 0.82, 0.68, respectively, showing slightly higher correlation. In addition, the local concentration deviation of some regions could be confirmed through 48 high density measuring networks. These results show that if a network of measurements is constructed with adequate spatial distribution using a number of simple meters with a certain degree of proven performance, the measurements are effective in monitoring local air quality and can be fully utilized to supplement or replace formal measurements.

• Korean Journal of Remote Sensing
• /
• v.36 no.6_3
• /
• pp.1721-1732
• /
• 2020

Elementary school students spend a lot of time in a school and are more exposed to indoor air pollution. Also the students are physically growing and have a relatively high respiratory rate per unit weight compared to adults, so it is known that there is a high sensitivity to indoor air pollution. Therefore, indoor air quality in a school is becoming an important factor for the student's health. In this study, a correlation analysis using levels of indoor and outdoor Particulate Matter (PM) measured from five elementary schools in Seoul was performed to evaluate the effect of outdoor PM on indoor PM. PM ratio and indoor/outdoor (I/O) ratio were also analyzed to investigate the actual condition of indoor air quality and effect of outdoor PM on indoor PM. As a result, the correlation between indoor and outdoor PM in elementary school was more significant in PM2.5 and PM1 than PM10. In the case of I/O ratio, the I/O ratio of PM10 was higher than that of 1 in four elementary schools except SD (BB:2.21, NS: 1.67, IS: 1.73, SI: 1.17). This indicates that the activity of students has a great effect on the concentration of indoor PM10.

• Journal of Environmental Science International
• /
• v.13 no.12
• /
• pp.1089-1102
• /
• 2004

Seasonal variation of biogeochemical characteristics was determined in Lake Shihwa from October 2002 to August 2003. When the lake was artificially constructed for the freshwater reservoir in 1988, the development of the strong haline density stratification resulted in two-layered system in water column and hypoxic/anoxic environment prevailed in the bottom layer due to oxidation of accumulated organic matters in the lake. Recently, seawater flux to the lake through the sluice has been increased to improve water quality in the lake since 2000, but seasonal stratification and hypoxic bottom layer of the lake still developed in the summer due to the nature of artificially enclosed lake system. As the lake is still receiving tremendous amount of organic matters and other pollutants from neighboring streams during the rainy summer season, limited seawater flux sluicing into the lake may not be enough for the physical and biogeochemical mass balance especially in the summer. The excess of accumulated organic matters in the bottom layer apparently exhausted dissolved oxygen and affected biogeochemical distributions and processes of organic and inorganic compounds in the stratified two-layered environment in the summer. During the summer, ammonia and dissolved organic carbon remarkably increased in the bottom layer due to the hypoxic/anoxic condition in the bottom layer. Phosphate also increased as the result of benthic flux from the bottom sediment. Meanwhile, dissolved organic carbon showed the highest value at the upstream area and decreased along the salinity gradient in the lake. In addition to the sources from the upstream, autochthonous origin of particulate organic carbon from algal bloom in the lake might be more important for sustaining aggravated water quality and development of deteriorated bottom environment in the summer. The removal of trace metals could be attributed to scavenging by strong insoluble metal-sulfide compounds in the hypoxic/anoxic bottom layer in the summer.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.6
• /
• pp.1159-1170
• /
• 2000

It is necessary to improve the ambient air quality through the proper treatment and control of pollutants by designating air pollutants to regulatory ones. Especially, human took a concern for particulate matters which raised visibility reduction, public health effects and injury of property for urban areas. In order to reduce the effect of particulate matters, we need to establish proper control strategies based on the concentration characteristics of particulate matters. In this study. to evaluate the characteristics of $PM_{2.5}$ and $PM_{10}$. thirty-eight samples of $PM_{2.5}$ and $PM_{10}$ were collected at Nam-Gu sampling site where continuous air monitoring system has been operated, from May, 1999 to November, 1999, and their concentrations for the mass and anion components($Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$) were analyzed. The important conclusions obtained in this study were as followings. Total average mass concentrations of $PM_{2.5}$ and $PM_{10}$ were 35.016 and $50.293{\mu}g/m^3$ respectively. and $PM_{2.5}/PM_{10}$ ratio was calculated 0.692. Total average concentrations of anion components in $PM_{2.5}$ were $1.581(Cl^-)$, $3.690(NO_3{^-})$ and $12.825(SO_4{^{2-}}){\mu}g/m^3$ and those in $PM_{10}$ were $2.471(Cl^-)$, $5.819(NO_3{^-})$ and $14.414(SO_4{^{2-}}){\mu}g/m^3$ respectively. From the correlations analysis. the correlation coefficient between mass concentration of $PM_{2.5}$ and $PM_{10}$ was calculated as 0.945. The correlation coefficients between $PM_{2.5}$ and anion components were analyzed as $Cl^-$(0.025), $NO_3{^-}$(0.788) and $SO_4{^{2-}}$(0.500) respectively, and the correlation coefficients between $PM_{10}$ and anion components were analyzed as $Cl^-$(-0.019), $NO_3{^-}$(0.806) and $SO_4{^{2-}}$)(0.535) respectively.