• Korean Journal of Mineralogy and Petrology
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• v.34 no.4
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• pp.255-264
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• 2021

Asian dust (Hwangsa) deposited on the surface of the Korean Peninsula is difficult to recognize their existence in mountainous terrain undergoing active erosion and weathering. This study examined Asian dust sediments mixed in soils by analysing clay mineralogy, mineral composition, and microtextures of fine silt (< 20 ㎛) in the alkali feldspar granite area of Seoraksan. The fine silt was composed of detrital particles derived from bedrocks, Asian dust sediments, and their weathering products. Clay minerals of 2:1 structural type, chlorite, amphibole, epidote, and Ca-bearing plagioclase were identified as eolian mineral particles. During the weathering of the bedrock composed of quartz and alkali feldspars, albite was partially weathered to produce small amounts of gibbsite and kaolin minerals. Hydroxy-Al interlayered clay minerals were formed by the exchange and fixation of polynuclear Al cationic species into the interlayers of expandable 2:1 clay minerals dominated by illite-smectite series clay minerals. Contribution of Asian dust to the fine silt of soils was estimated around 70% on the basis of total contents of 2:1 phyllosilicates.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3651-3656
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• 2012

The size-segregated atmospheric aerosols have been collected at 1100 m site of Mt. Halla in Jeju, a background area in Korea, using 8-stage cascade impact air sampler during Asian dust and non-Asian dust storm periods. Their ionic and elemental species were analyzed, in order to examine the pollution characteristics and composition change between Asian dust and non-Asian dust periods. The major ionic species such as nss-$SO_4{^{2-}}$, $NH_4{^+}$, and $K^+$ were predominantly distributed in the fine particles (below $2.1{\mu}m$ diameter), and besides the $NO_3{^-}$ was distributed more in coarse particle fraction than fine particle. On the other hand, the typical soil and marine species i.e., nss-$Ca^{2+}$, $Na^+$, $Cl^-$, and $Mg^{2+}$, were mostly existed in the coarse particles (over $2.1{\mu}m$ diameter). As well in the elemental analysis of aerosols, the major soil-originated Al, Fe, Ca, and others showed prominently high concentrations in the coarse particle fraction, whereas the anthropogenic S and Pb were relatively high in the fine particle fraction. From the comparison of aerosol compositions between Asian dust and non-Asian dust periods, the concentrations of the soil-originated species such as nss-$Ca^{2+}$, Al, Ca, Fe, Ti, Mn, Ba, Sr have increased as 2.7-4.2 times during the Asian dust periods. Meanwhile the concentrations of nss-$SO_4{^{2-}}$ and $NO_3{^-}$ have increased as 1.4 and 2.0 times, and on the contrary $NH_4{^+}$ concentrations have a little bit decreased during the Asian dust periods. Especially the concentrations of both soil-originated ionic and elemental species increased noticeably in the coarse particle mode during the dust storm periods.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.21-35
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• 2009

The Asian dust storms which originated in the deserts of Mongolia and China transported particles to Korea and led to a high concentration of atmospheric particulate matters (PM) of more than $1000{\mu}g/m^3$ throughout the country in the spring, of 2007. Public concern, in Korea, about the possible adverse effects of these dust events has increased, as these dust storms can contain various air pollutants emitted from heavily industrialized eastern China. The objectives of this study were to understand the concentration characteristics of PM as a function of particle size between the Asian dust storm episodes and non-Asian dust period and to consider the mass size distribution of PM in the Asian dust storms and their water soluble ion species on the potential, possible effects on deposition levels in the three regions (nasopharyngeal, tracheobronchial, and alveolar) of the human respiratory system. The size distribution of PM mass concentration during the Asian dust storms showed a peak in the coarse particle region due to the long-range transport of soil particles from the deserts of Mongolia and China, which was identified by HYSPLIT-4 model for backward trajectory analysis of air arriving in the sampling site of Iksan. During the non-Asian dust period, there were two different types in PM size distribution: bimodal distribution when low concentrations of $PM_{2.5}$ were observed, while unimodal distribution having a peak in fine particle region when high concentrations of $PM_{2.5}$ were showed. This unimodal distribution with high concentrations of fine particulate and secondary air pollutants such as ${SO_4}^{2-}$, ${NO_3}^-$, ${NH_4}^+$ was found to be due to the long-range transport of air pollutants from industrialized eastern China. During the Asian dust storms, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $128.8{\mu}g/m^3$, $216.5{\mu}g/m^3$, and $89.6{\mu}g/m^3$, respectively. During the non-Asian dust period, the mean concentrations of PM that can be deposited in the nasopharyngeal, tracheobronchial, and alveolar region were $8.4{\mu}g/m^3$, $9.5{\mu}g/m^3$ and $38.5{\mu}g/m^3$, respectively.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.356-357
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.47-50
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• 2006

• The Bulletin of The Korean Astronomical Society
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• v.10
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• pp.4.1-4.1
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• 1985

• Particle and aerosol research
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• v.11 no.2
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• pp.37-46
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• 2015

Dust particles, which inflow to the subway mechanical ventilation and air conditioning(MVAC) chamber, contain a fair amount of iron compounds, approximately 25.2w/w%. This work attempted to capture those iron containing dust using magnetic filters. Average magnetization value of the test MVAC dust was 0.012 emu on 5,000 Oe, which could correspond sufficiently with the magnetic interaction. External permanent magnets provided with magnetization of iron mesh screen showing high gradient magnetic field(HGM). It resulted in the capture efficiency with 84.0 ~ 99.7% and 81.2 ~ 99.8% for $PM_{10}$ and $PM_{2.5}$ respectively. Magnetic capture was found to be closely associated with the magnetic intensity, mesh opening size and flow velocity.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.84-91
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• 2010

The centrifugal oil purifier is used in ships for purifying the engine lubrication oil. The momentum needed for the rotation of the cylindrical chamber is obtained by jet injections. The dust particles in the oil are separated by the centrifugal forces moving to the inner wall of the rotating cylindrical chamber body. The dust particles are eliminated when the particles are adsorbed onto the surface of the inner wall of the chamber body. The flow characteristics and the physical behaviours of particles in this centrifugal oil purifier have been investigated numerically and the filtration efficiencies have been evaluated. For the calculations, a commercial code has been used and the SST k-${\omega}$ turbulence model has been adopted. The MRF (Multiple Reference Frame) method has been introduced to consider the rotating effect of the flows. Under various variables, such as particle size, particle density and rotating speed, the filtration efficiencies have been evaluated. It has been verified that the filtration efficiency is increased with the increments of the particle size, the particle density and the rotating speed of the cylindrical chamber.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.3
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• pp.367-375
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• 2008

To characterize atmospheric particles in Cheonan area, 5 monitoring sites representing highway area, commercial area, residential area, and industrial areas were selected, and the mass concentrations of PM10 and PM2.5 were monitored for 14 days at each site during 2007. The daily average PM10 and PM2.5 concentrations were in the range from 18.5 to $140.9{\mu}g/m^3$ and 8.2 to $116.6{\mu}g/m^3$, respectively, showing the highest mean concentrations at the commercial area site and the lowest concentration at the residential area site. The daily average PM 10 concentrations at Shinan (Commercial area) and Bakseok (Industrial area) sites were exceeded the current National Standard for 1 and 2 days during the monitoring periods. The fractions of PM2.5 in PM10 were above 70% for all sites, indicating fine particles are the major constituent of atmospheric particles in Cheonan. The results indicate that PM10 concentrations in Cheonan are at the concerning level, and the control strategy for fine particles is necessary to address this issue.

• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.665-672
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• 2018

A venturi scrubber is an important element of Filtered Containment Venting System (FCVS) for the removal of aerosols in contaminated air. The present work involves computational fluid dynamics (CFD) study of dust particle removal efficiency of a venturi scrubber operating in self-priming mode using ANSYS CFX. Titanium oxide ($TiO_2$) particles having sizes of 1 micron have been taken as dust particles. CFD methodology to simulate the venturi scrubber has been first developed. The cascade atomization and breakup (CAB) model has been used to predict deformation of water droplets, whereas the Eulerian-Lagrangian approach has been used to handle multiphase flow involving air, dust, and water. The developed methodology has been applied to simulate venturi scrubber geometry taken from the literature. Dust particle removal efficiency has been calculated for forced feed operation of venturi scrubber and found to be in good agreement with the results available in the literature. In the second part, venturi scrubber along with a tank has been modeled in CFX, and transient simulations have been performed to study self-priming phenomenon. Self-priming has been observed by plotting the velocity vector fields of water. Suction of water in the venturi scrubber occurred due to the difference between static pressure in the venturi scrubber and the hydrostatic pressure of water inside the tank. Dust particle removal efficiency has been calculated for inlet air velocities of 1 m/s and 3 m/s. It has been observed that removal efficiency is higher in case of higher inlet air velocity.