• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.407-419
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• 1996

Characteristics of visual air quality in Seoul have been investigated between June 13 and 21, 1994. Optical properties (extinction coefficient and particle scattering coefficient), meteorological parameters (relative humidity, temperature, wind speed, wind direction, and cloud cover), particle characteristics (mass size distribution, components) were measured and analyzed. During measurement periods, northwest wind with less than 2m/sec of wind speed deteriorates visibility. Effects of relative humidity are though to be not a direct factor which influence to visibility through the size change due to hygroscopic species in aerosol. During the smoggy period both the aerosol mass concentration and fine particle fraction of the size distribution are increased compared to the clear period. Sulfate, organic carbon, and elemental carbon in aerosol are the major species in determining the occurrence and severity of a smog in Seoul.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.444-449
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• 1973

From the methanol extract of the fruits of Forsythia Koreana NAKAI a sapogenin and its derivatives were isolated. Through the mass spectra, ultraviolet spectra, nuclear magnetic resonance spectra, elemental analysis and chemical tests it was identified as ursolic acid.

• Carbon letters
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• v.5 no.2
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• pp.68-74
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• 2004

The polymer with contents of $C_{60}$ up to 57 wt.% was produced by mutual condensation of fullerene $C_{60}$ and ethylenediamine. The investigations of this polymer as well as pristine fullerene to comparison were carried out by FT-IR and UV-Vis spectroscopy, ToF-SIMS, TGA, and elemental analysis. At least three kinds of components was revealed as building blocks of polymer. The fullerene cage underwent only distortion but didn't destroy during formation of polymer. The pure fullerene was found as an intermediate of the thermal decomposition of polymer. The conclusion that this polymer could serve as precursor to produce carbon nanomaterial with high concentration curved graphene sheets and can be used for gas adsorption and electrochemical application was made.

• Journal of the Korean Chemical Society
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• v.15 no.1
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• pp.1-3
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• 1971

The methanol extract of the fruits of Forsythia Koreana NAKAI was separated and purified. The quaternary base chloride was obtained. Through the mass spectrogram, ultraviolet spectra, infrared spectra, elemental analysis and qualitative tests it was identified as betaine hydrochloride.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.647-661
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• 2003

For continuous monitoring of atmospheric visibility in the city of Kwanaju, Korea, a transmissometer system consisting of a transmitter and a receiver was installed at a distance of 1.91 km across the downtown Kwanaju. At the transmitter site an integrating nephelometer and an aethalometer were also installed to measure the scattering and absorption coefficients of the atmosphere, respectively. At the receiver site. an URG PM$_{2.5}$ cyclone sampler and an URG-VAPS (Versatile Air Pollutant Sampler) with three filter packs and two denuders were used to collect both PM$_{2.5}$ and PM$_{10}$ samples at a 2-hour or 12-hour sampling interval for aerosol chemical analysis. Sulfate, organic mass by carbon (OMC), nitrate, elemental carbon (EC) components of fine aerosol were the major contributors to visibility impairment. Diurnal variation of visibility during best-case days showed rapid improvement in the morning hours, while it was delayed until afternoon during the worst-case days. Aerosol mass concentration of each aerosol component for the worst-case was calculated to be 11.2 times larger than the best-case for (NH$_4$)$_2$SO$_4$(NHSO), 19.0 times for NH$_4$NO$_3$ (NHNO), 2.2 times for OMC, respectively. Also result shows that elemental carbon and fine soil (FS) were 3.7 and 2.2 times more than those of best-case. respectively- Sum of total contributions of wet NHSO and NHNO to light extinction was calculated to be 301 Mm$^{-1}$ for the worst-case. However, sum of contributions by dry NHSO and NHNO was calculated to be 123 Mm$^{-1}$ for the best case. Mass extinction efficiencies of fine and coarse particles were calculated to be 5.8$\pm$0.3 $m^2$/g and 1.8$\pm$0.1 $m^2$/g, respectively.ely.

• Asian Journal of Atmospheric Environment
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• v.11 no.2
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• pp.122-130
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• 2017

The main purpose of the study was to clarify the properties of individual particles collected at each behavior space of a factory worker. The samplings of size-segregated ($PM_{2.1-1.1}$ and $PM_{4.7-3.3}$) indoor particles were conducted at three different behavior spaces of a factory worker who is engaged in an auto parts manufacturing plant (i.e., his home, his work place in factory, and his favorite restaurant). Elemental specification (i.e., relative elemental content and distribution in and/or on individual particles) was performed by a micro-PIXE system. Every element detected from the coarse particulate matters of home was classified into three groups, i.e., a group of high net-counts (Na, Al, and Si), a group of intermediate net-counts (Mg, S, Cl, K, and Ca), and a group of minor trace elements (P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb). The results of EF for $PM_{4.7-3.3}$ in home indicated that several heavy metals were generated from the sources within the house itself. An exceptional feature shown in the individual particles in workplace is that Cr, Mn, and Co were clearly detected in both fine and coarse particles. Cluster analysis suggested that the individual coarse particles ($PM_{4.7-3.3}$) collected at the indoor of factory were chemically heterogeneous and they modified with sea-salt, mineral, and artificially derived elements. The principal components in individual coarse particles collected at restaurant were sea-salt and mineral without mixing with harmful trace elements like chromium and manganese. Compared to the indoor fine particles of home and restaurant, many elements, especially, Cl, Na, Cr, Mn, Pb, and Zn showed overwhelmingly high net-counts in those of factory.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.14-22
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• 2012

This paper is focused on the comprehensive and detailed interpretation for the chemical transformation of individual Asian dust (hereafter called "AD") particles during long-range transport from source regions to receptor area. A multi-stage particle sampler was operated at a ground-based site in Taean, Korea directly exposed to the outflow of air masses from China during AD period in April 2003. Both quantitative and qualitative analyses for size-classified individual particles were carried out by a microbeam X-ray fluorescence (XRF) method and a microbeam Particle Induced X-ray Emission (micro-PIXE), respectively. Among major characteristic elements, the elemental masses of soil derived components, sulfur, and chloride varied as a function of particle size showing the monomodal maximum with a steeply increasing at 3.3-4.7 ${\mu}m$ particle size. Although the details on chemical composition of AD particle collected on a straight line from source area to our ground-based site are needed, a large amount of Cl coexisted in and/or on AD particles suggests that AD particles collected in the present study might be actively engaged in chemical transformation by sea-salt and other Cl containing pollutants emitted from the China's domestic sources. Through the statistical analyses it was possible to classify individual AD particles into six distinct groups. The internally mixed AD particles with Cl, which has various sources (e.g., sea-salt, coal combustion origin HCl, gaseous HCl derived from the adsorption of acids to sea-salt, and Cl containing man-made particles) were thoroughly fractionated by the elemental spectra drivened by the double detector system of micro-PIXE.

• Asian Journal of Atmospheric Environment
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• v.4 no.2
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• pp.80-88
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• 2010

In order to offer a better understanding of air pollution of China as well as East Asia we attempted to characterize the chemical properties of the raw coal materials mined in China and their combusted bottom ashes generated from coal fired power plant. To this end, we measured the chemical characteristics of individual bottom ashes and feed coal fragments collected at a coal fired power generator which was operated with the raw coal dug at a coal mine in China. The chemical properties of these two sample types were determined by a synchrotron radiation X-ray fluorescence (SR-XRF) microprobe method. Through an application of such technique, it was possible to draw the 2D elemental maps in and/or on raw coal fragments and fired bottom ashes. The pulverized fine pieces of feed coal mainly consisted of mineral components such as Fe, Ca, Ti, Ca, and Si, while Fe was detected as overwhelming majority. The elemental mass of combusted bottom ash shows strong enrichment of many elements that exist naturally in coal. There were significant variations in chemical properties of ash-to-ash and fragment-to-fragment. Although we were not able to clearly distinguish As and Pb peaks because of the folding in their X-ray energies, these two elements can be used as tracers of coal fire origin.

• Journal of Environmental Science International
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• v.27 no.7
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• pp.543-554
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• 2018

From November 2013 to December 2016, ambient fine particulate matter ($PM_{2.5}$) was sampled in the downtown area of Jeju City, South Korea, which has seen rapid urbanization. The atmospheric concentrations of elements were measured in the $PM_{2.5}$ samples. This study focused on Cd, Cr, Cu, Mn, Ni, Pb, As, Sb, Sn, V, and Zn. The concentrations of Al, Na, K, Fe, Ca, Mg, Sr, and La were also obtained for reference. The objectives of this study were to examine the contributions of these elements to $PM_{2.5}$ concentrations in downtown Jeju City, and to investigate the inter-element relationships and the elemental sources by using enrichment factors and principal components analysis (PCA). A composition analysis showed that the 19 elements constituted 6.65 % of the $PM_{2.5}$ mass, and Na, K, Al, Fe, Ca, Mg, and Zn constituted 98 % of the total ion mass. Seasonal trend analysis for the sampling period indicated that the concentrations of the elements increased from November to April. However, no substantial seasonal variations were found in the concentrations of the elements. The composition ratios of some elements (Cu/Zn, Cu/Cd, Cu/Pb, V/Ni, and V/La) were found to be out of range when compared to the literature from other urban areas. The ratios between the elements and the PCA results showed that local contaminant sources in Jeju City rarely influence the composition of $PM_{2.5}$. This suggests that the major sources of $PM_{2.5}$ in Jeju City may include long-range transport of fine particulate matter produced in other areas.

• Journal of Environmental Science International
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• v.30 no.10
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• pp.845-861
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• 2021

This study investigated the variations in monthly PM_2.5 concentrations and their characteristics at the sampling site (35.075°N, 129.080°E) around the Busan seaport area for six months (from August 2020 to January 2021). Monthly PM_2.5 concentrations in the filtered samples ranged from 8.4 to 42.3 ㎍/m³ (average=19.6±8.2 ㎍/m³, n=50) and were generally high in August, December, and January, and low in September, October, and November. The variations of monthly PM_2.5 concentrations showed similar patterns to those of the neighboring national air quality monitoring sites. The contents of Total Carbon (TC), Organic Carbon (OC), Elemental Carbon (EC), and OC/EC ratios in PM_2.5 showed large variability during the study period. The OC/EC ratios ranged from 4.2 to 34.4, suggesting that the relative contributions of OC and EC to the PM_2.5 concentrations changed temporally and might be related to their formation sources. Variations in the chemical components of and particle size distributions in PM_2.5 showed that high PM_2.5 concentrations were affected by various sources, such as sea salt and ship emission. The precursor gas concentrations were discussed in terms of monthly variations and their contributions to PM_2.5 concentrations. However, further research is needed to understand the characteristics and behaviors of PM_2.5 concentrations around the Busan seaport area.