• Asian Journal of Atmospheric Environment
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• v.1 no.1
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• pp.14-18
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• 2007

The Korean government enacted the "Special Law for Improving Air Quality of Metropolitan Area" in 2003. According to this plan, Korean government plan to lower the concentrations of $PM_{10}$ and $NO_x$ to $40{\mu}g/m^3$ and 22 ppb, respectively, by 2014. In this study, we analyze emission reduction strategies to lower their concentration. Emission reduction for the supply of mass energy and regenerative energy are compared with several scenarios. According to the results, 713 t/y of $NO_x$ and 165 t/y of $PM_{10}$ will be reduced by enhancing the number of households supplied by local heating and air conditioning. And also 5 t/y of $PM_{10}$ and 312 t/y of $NO_x$ will be reduced by replacing conventional energy with solar energy by 2014.

• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.126-133
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• 2019

Objectives: In this study, a nine-stage cascade impactor was used to collect dust, and the concentration of $PM_{2.1}$ & $PM_{10}$ and alveolar deposition ratio were investigated. Methods: This study was conducted at Kunsan National University from May to June 2016. A nine-stage Cascade Impactor was used to analyze the concentrations of fine and ultrafine dust and to estimate the alveolar deposition rate by particle size of atmospheric dust particles. The pore size of each stage of the collector used in this study gradually increased from F to 0, with the F-stage as the last stage. Results: The mass fraction of PM showed a bimodal distribution divided into $PM_{2.1}$ & $PM_{10}$ based on $2.1-3.1{\mu}m$. The average mass fraction of particulate matter in the range of $2.1-3.1{\mu}m$ was 44%, and the area occupied by $PM_{2.1}$ was similar. Therefore, the Gunsan area is considered to be a region where there are similar effects from anthropogenic and natural sources. Conclusion: Dust collecting efficiency increased with the stage of collecting fine dust, and the efficiency of collection was very low at the stage of collecting ultra-fine dust. The seasonal overall efficiency of the Cascade Impactor was 44% in spring and 37.4% in summer, and the average overall efficiency was 40.7%. The alveolar deposition rate of $PM_{2.1}/PM_{10}$ during the sampling period was estimated to be about 75% deposited in the alveoli.

• Journal of Environmental Impact Assessment
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• v.12 no.2
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• pp.99-108
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• 2003

We collected and analyzed PM10 samples to account for the characteristics of heavy metallic elements for yellow sand and non-yellow sand during springtime of 2002 at Busan, The mean PM10 mass concentration for springtime of 2002 was $219.82{\mu}g/m^3$ with the maximum $787.50{\mu}g/m^3$ and the minimum $19.44{\mu}g/m^3$. The mean concentration of metallic elements contained in PM10 are shown as follows : Si>Ca>Fe>Al>Na, respectively. The ratio of mean PM10 mass concentration for yellow sand($362.7{\mu}g/m^3$) to that for non-yellow sand($48.3{\mu}g/m^3$) was 7.5, the significant positive correlation (P<0.05) was found between yellow sand and non-yellow sand. The metallic elements concentration ratios of yellow sand to the non-yellow sand were over 10 times for Al, Ca, Mg, 4~8 times for Fe, Si, Mn. But the concentration of Na, Cu, Zn for non-yellow sand was higher than those of yellow sand. The crustal enrichment factor of Cd, Cu, Pb, Zn, Cr, K, Mn, Na, Ni for yellow sand was higher that of non-yellow sand over 10 times, and concentration rate of soil particles of yellow sand was increased 2.3 times that of nonyellow sand.

• Journal of Environmental Health Sciences
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• v.36 no.1
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• pp.61-71
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• 2010

Intensive measurements of airborne respirable $PM_{2.5}$ and inhalable $PM_{2.5}$ were conducted in the downtown area of Iksan city. The $PM_{2.5}$ and $PM_{2.5}$ samples were collected twice a day in the Iksan city of Korea from October 17 to November 1, 2004. The purpose of the study was to determine the inorganic water-soluble components and trace elements of $PM_{2.5}$ and $PM_{2.5}$ in the atmospheric environment and estimate the contribution rate of major chemical components from a mass balance of all measured particulate species. The chemical analysis for PM samples was conducted for water-soluble inorganic ions using ion chromatography and trace elements using PIXE analysis. The mean concentrations of respirable $PM_{2.5}$ and inhalable $PM_{2.5}$ were $51.4{\pm}29.7$ and $79.5{\pm}39.6\;{\mu}g/m^3$, respectively, and the ratio was 0.62. The ion species of $NO_3$, $SO_4^2$, and $NH_4^+$ were abundant in both $PM_{2.5}$ and $PM_{2.5}$. These components predominated in respirable $PM_{2.5}$ fraction, while $Na^+$, $Mg^{2+}$, $Ca^{2+}$ mostly existed in coarse particle mode. Elemental components of S, Cl, K, and Si were abundant in both $PM_{2.5}$ and $PM_{2.5}$. These elements, except for Si, were considered to be emitted from anthropogenic sources, while Si, Al, Fe, Ca existed mainly in coarse particle mode and were considered to be emitted from crustal materials. The averaged mass balance analysis showed that ammonium nitrate, ammonium sulfate, crustal component, and other trace elements were composed of 18.4%, 13.2%, 4.8%, 3.5% for PM2.5 and 17.0%, 11.6%, 13.7%, 4.4% for $PM_{2.5}$, respectively.

• Journal of the Korean earth science society
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• v.31 no.6
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• pp.600-607
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• 2010

In 2008, multiple episodes of large-scale transport of natural airborne particles and anthropogenically affected particles from different sources in the East Asian continent were identified in the National Oceanic and Atmospheric Administration (NOAA) satellite RGB-composite images and the mass concentrations of ground level particulate matters. To analyze the aerosol size distribution during the large-scale transport of atmospheric aerosols, both aerosol optical depth (AOD; proportional to the aerosol total loading in the vertical column) and fine aerosol weighting (FW; fractional contribution of fine aerosol to the total AOD) of Moderate resolution Imaging Spectroradiometer (MODIS) aerosol products were used over the East Asian region. The six episodes of massive natural airborne particles were observed at Cheongwon, originating from sandstorms in northern China, Mongolia and the loess plateau of China. The $PM_{10}$ and $PM_{2.5}$ stood at 70% and 16% of the total mass concentration of TSP, respectively. However, the mass concentration of $PM_{2.5}$ among TSP increased as high as 23% in the episode in which they were flowing in by way f the industrial area in east China. In the other five episodes of anthropogenically affected particles that flowed into the Korean Peninsula from east China, the mass concentrations of $PM_{10}$ and $PM_{2.5}$ among TSP reached 82% and 65%, respectively. The average AOD for the large-scale transport of anthropogenically affected particle episodes in the East Asian region was measured at $0.42{\pm}0.17$ compared with AOD ($0.36{\pm}0.13$) for the natural airborne particle episodes. Particularly, the regions covering east China, the Yellow Sea, the Korean Peninsula, and the east Korean sea were characterized by high levels of AOD. The average FW values observed during the event of anthropogenically affected aerosols ($0.63{\pm}0.16$) were moderately higher than those of natural airborne particles ($0.52{\pm}0.13$). This observation suggests that anthropogenically affected particles contribute greatly to the atmospheric aerosols in East Asia.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.5
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• pp.420-431
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• 2009

Characteristics and advantages of the thermal desorption-comprehensive two dimensional gas chromatography-time of flight mass spectrometry (TD-GCxGC-TOFMS) were discussed and the organic compound's analysis result was shown for the ambient $PM_{2.5}$ sample collected in Seoul, Korea. Over 10,000 individual organic compounds were separated from about $70{\mu}g$ of aerosols in a single procedure with no sample pre-treatment. Among them, around 300 compounds were identified and classified based on the mass fragmentation patterns and GCxGC retention times. Several aliphatic compounds groups such as alkanes, alkenes, cycloalkanes, alkanoic acids, and alkan-2-ones were identified as well as 72 PAH compounds including alkyl substituted compounds and 8 hopanes. In Seoul aerosol, numerous oxidized aromatic compounds including major components of secondary organic aerosols were observed. The inventory of organic compounds in $PM_{2.5}$ of Seoul, Korea suggested that organic aerosol were constituted by the compounds of primary source emission as well as the formation of secondary organic aerosols.

• Journal of Environmental Science International
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• v.24 no.6
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• pp.777-784
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• 2015

This study investigates weekday/weekend characteristics of $PM_{10}$ and $PM_{2.5}$ concentration and metallic elements in Busan in the springtime of 2013. $PM_{10}$ concentration on weekday/weekend were 77.54 and $67.28{\mu}g/m^3$, respectively. And $PM_{2.5}$ concentration on weekday/weekend were 57.81 and $43.83{\mu}g/m^3$, respectively. Also, $PM_{2.5}/PM_{10}$ concentration ratio on weekdays/weekend was 0.75 and 0.65, respectively. The contribution rates of Na to total metallic elements in $PM_{10}$ on weekday/weekend were 38.3% and 38.9%, respectively. It would be useful in control effectively with management of urban fine particle to understand characteristics of fine particle concentration on weekday/weekend.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.313-319
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• 2012

Mass production method on artificial seedling production of hard clam Meretrix petechialis was developed indoor culture system. Spawning of adult clam (SL $65.8{\pm}8.4mm$) was induced using the combined method of air exposure and water temperature raising. The fertilized eggs were developed to D-shaped larvae after 17.7 hours at $27^{\circ}C$ and hatching rate was 6.1%. Shell length (SL) of D-shaped larvae was measured to be $131.4{\pm}2.6{\mu}m$ and thereafter the larvae grew to the settled spats with SL $190.2{\pm}7.5{\mu}m$ in 4 days. Estimated survival rate of settled spats was 48.1%. Spat collection on 130,000 spats with SL $0.19{\pm}0.01mm$ performed conducted by sand bottom circulation filtering method. Collected spats grew up to $3.1{\pm}0.8mm$ in 46 days, $6.6{\pm}1.8mm$ in 87 days, and $10.5{\pm}0.9mm$ in 114 days. The relative growth between SL and shell height (SH) was calculated to be SH = 0.8501SL + 0.0196 ($R^2=0.9987$) during the whole spat period. During spats rearing, they were suffered from one time of mass mortality at SL 3.1 mm, but 51,000 spats were finally survived with the rate of 39.2% at 114 days of spat rearing in indoor tank system.

• Journal of Korean Neurosurgical Society
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• v.30 no.2
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• pp.131-136
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• 2001

Object : The clinical uses of screws are increasing with broader applications in spinal disorders. When screws are inserted repeatedly to achieve optimal position, tips of screw pitch may become damaged during insertion even though there are significant differences in the moduli of elasticity between bone and titanium. The effect of repeated screw insertion on pullout resistance was investigated. Methods : Three different titanium screws(cortical lateral mass screw, cancellous lateral mass screw and cervical vertebral body screw) were inserted into the synthetic cancellous material and then extracted axially at a rate of 2.4mm/min using Instron(Model TT-D, Canton, MA). Each set of screws was inserted and pulled out three times. There were six screws in each group. The insertional torque was measured with a torque wrench during insertion. Pullout strength was recorded with a digital oscilloscope. Results : The mean pullout force measurements for the cortical lateral mass screws($185.66N{\pm}42.60$, $167.10N{\pm}27.01$ and $162.52 N{\pm}23.83$ for first, second and third pullout respectively : p=0.03) and the cervical vertebral body screws($386.0N{\pm}24.1$, $360.2N{\pm}17.5$ and $330.9N{\pm}16.7$ : p=0.0024) showed consecutive decrease in pullout resistance after each pullout, whereas the cancellous lateral mass screws did not($194.00N{\pm}36.47$, $219.24N{\pm}26.58$ and 199.49N(36.63 : p=0.24). The SEM after insertion and pullout three times showed a blunting in the tip of the screw pitch and a smearing of the screw surface. Conclusions : Repetitive screw insertion and pullout resulted in the decrease of pullout resistance in certain screws possibly caused by blunting the screw tip. This means screw tips suffer deformations during either repeated insertion or pullout. Thus, the screws that have been inserted should not be used for the final construct.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.63-71
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• 2001

PM 2.5/ samples were measured at two sites, Hadan(suburban site) and Anrak (roadside site) in Busan area. PM 2.5/ sampling was performed for 24-hour intervals by the FH9.5 particulate sampler. Aerosol samples were collected on PTFE filter. A total of 60 particulate samples were collected, dad samples were measured for Particulate mass concentration, metallic elements (Cr, Mn, Ni. Cu. Se, Fe, Pb, and Zn) and waer-soluble elements (C $l^{[-10]}$ , N $O_{3}$$^{[-10]}$ ,S $O_{4}$$^{2-}$, N $H_{4}$$^{+}$, $Ca_{2}$$^{+}$, $Mg_{2}$$^{+}$ and $^{+}$.Mass concentration in Hadan ranged 24.23~57.12 $\mu\textrm{g}$/㎥ and 60.22~72.12 $\mu\textrm{g}$/㎥m Yellow Sand Events. Major cations in Hadan and Anrak site is N $H_{4}$$^{+}$and N $a^{+}$ respectively. SO42$^{[-10]}$ was the abundant specie in the PM 2.5 fraction for Hadan site an dAnrak site. Hadan site showed igher concentration in S $O_{4}$$^{2.1}$ and N $H_{4}$ $^{+}$ In Anrak site the concentration of S $O_{4}$/sip 2-/and N $a^{+}$ was higher than other ions Prominent metallic elements were Fe and Pb in two sites. Principal component analysis showed that main source of PM 2.5 aerosol particles was non-metal related source which was resulted in relating elements as Cr, Ni, and Pb at Hadan site, Anrak site also has resulted PM2.5 aerosol paricles source, which was related its element like Zn, and Ni,. The SAS package analysis also showed that long-range transport effect at Hadan area due to Yellow Sand Event by the prevailing weaterlies.ling weaterlies.