• 한국입자에어로졸학회지
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• 제15권3호
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• pp.91-104
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• 2019

In this study, hourly measurements of $PM_{2.5}$ and its major chemical constituents such as organic and elemental carbon (OC and EC), and ionic species were made between January 15 and February 10, 2018 at the air pollution intensive monitering station in Gwangju. In addition, 24-hr integrated $PM_{2.5}$ samples were collected at the same site and analyzed for OC, EC, water-soluble OC (WSOC), humic-like substance (HULIS), and ionic species. Over the whole study period, the organic aerosols (=$1.6{\times}OC$) and $NO_3{^-}$ concentrations contributed 26.6% and 21.0% to $PM_{2.5}$, respectively. OC and EC concentrations were mainly attributed to traffic emissions with some contribution from biomass burning emissions. Moreover, strong correlations of OC with WSOC, HULIS, and $NO_3{^-}$ suggest that some of the organic aerosols were likely formed through atmospheric oxidation processes of hydrocarbon compounds from traffic emissions. For the period between January 18 and 22 when $PM_{2.5}$ pollution episode occurred, concentrations of three secondary ionic species ($=SO{_4}^{2-}+NO_3{^-}+NH_4{^+}$) and organic matter contributed on average 50.8 and 20.1% of $PM_{2.5}$, respectively, with the highest contribution from $NO_3{^-}$. Synoptic charts, air mass backward trajectories, and local meteorological conditions supported that high $PM_{2.5}$ pollution was resulted from long-range transport of haze particles lingering over northeastern China, accumulation of local emissions, and local production of secondary aerosols. During the $PM_{2.5}$ pollution episode, enhanced $SO{_4}^{2-}$ was more due to the long-range transport of aerosol particles from China rather than local secondary production from $SO_2$. Increasing rate in $NO_3{^-}$ was substantially greater than $NO_2$ and $SO{_4}^{2-}$ increasing rates, suggesting that the increased concentration of $NO_3{^-}$ during the pollution episode was attributed to enhanced formation of local $NO_3{^-}$ through heterogenous reactions of $NO_2$, rather than impact by long-range transportation from China.

• 한국대기환경학회지
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• 제25권2호
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• pp.141-153
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• 2009

$PM_{2.5}$ samples were collected from December 2005 through November 2007 in two cities including Chuncheon and Seoul in order to investigate the characteristics of carbonaceous aerosol. The average $PM_{2.5}$ concentration in Seoul ($43.2{\mu}g/m^3$) was approximately 1.2 times higher than that measured in Chuncheon ($36.1{\mu}g/m^3$), however there was no statistical difference on $PM_{2.5}$ concentration between those two cities. Backward trajectories were passing through Seoul area before arriving Chuncheon for about half of the samples, and $PM_{2.5}$ largely increased in Chuncheon when back-trajectories originated from Seoul area. Total carbon (TC) was calculated as sum of OC and EC, contributing 20.5% and 29.2% to total $PM_{2.5}$ mass in Chuncheon and Seoul, respectively. The average ratio of secondary organic carbon (SOC) to total OC was 40% at both sites, and the highest SOC concentration was observed in summer probably due to enhanced volatilization of organic species and active photochemical reaction. J value was calculated to determine if acidic condition affected the increase of secondary organic carbon. In both Chuncheon and Seoul SOC/OC ratios were fairly enhanced when J<100% of acidic condition.

• 한국대기환경학회지
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• 제29권5호
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• pp.553-573
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• 2013

This paper aims to give a summary and review of the research trend about subjects of Asian Dust (AD) storm in the last three decades. The AD research was focused on classification of synoptic scale data and finding inflow pathway in early stage. Recently, new approaches have been made to explain chemical composition, transportation, transboundary movement reaction of AD, using satellite data, 3D modeling, the aerosol time of flight mass spectroscopy, etc. During AD events, a large amount of dust particles flow into Korea and Japan from AD source areas, and they are highly likely to be mixed with toxic substances when air mass contained AD particles pass over seriously polluted areas. We concluded that, considering that AD events were classified into two cases according to the source area and pathway, the concentrations of crustal components did not increase at the initial stage of AD events, Whereas ammonium-sulfate, trace metal element, OC, EC relatively increased in the early stage. This explains AD events have the possibility of being accompanied with polluted air mass or particles. Also, we further need to compare and summarize the results of AD studies which already have been conducted, and prepare strategies for particle management, particularly for Black Carbon (BC) and Brown Carbon (BrC) which are considered to induce climate change effects.

• 한국대기환경학회지
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• 제28권3호
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• pp.282-293
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• 2012

This study aimed to show the chemical characteristics of $PM_{10}$ and $PM_{2.5}$ during Asian dust (AD) events and high PM episodes observed in Seoul. Time-resolved chemical composition of $PM_{10}$ or $PM_{2.5}$ was monitored in 1 hour interval using ambient ion monitor, semi-continuous carbon monitor, and on-line XRF spectrometer at Seoul intensive monitoring site in 2009. Considering that AD events were classified into three different cases according to the source area and pathway, the concentrations of ammonium-sulfate and trace metal components were relatively high when the AD were occurred in Gobi and inner-mongolia and transported across the Bohai bay. In addition, the influence of alkaline dust, which carried from saline land located in the northeastern China, was observed when the AD was originated from Gobi, inner-mongolia, and Manchuria. Except AD events, the high PM episodes observed in Seoul were impacted by various anthropogenic sources such as biomass burning, motor vehicle, oil combustion and road dust.

• 한국대기환경학회지
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• 제19권6호
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• pp.701-717
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• 2003

The objective of this study was to extensively estimate the air quality trends of the study area by surveying con-centration trends in months or seasons, after analyzing the mass concentration of PM-10 samples and the inorganic lements, ion, and total carbon in PM-10. Also, the study introduced to apply the PMF (Positive Matrix Factoriza-tion) model that is useful when absence of the source profile. Thus the model was thought to be suitable in Korea that often has few information about pollution sources. After obtaining results from the PMF modeling, the existing sources at the study area were qualitatively identified The PM-10 particles collected on quartz fiber filters by a PM-10 high-vol air sampler for 3 years (Mar. 1999∼Dec.2001) in Kyung Hee University. The 25 chemical species (Al, Mn, Ti, V, Cr, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, Ce, Pb, Si, N $a^{#}$, N $H_4$$^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$, C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, TC) were analyzed by ICP-AES, IC, and EA after executing proper pre - treatments of each sample filter. The PMF model was intensively applied to estimate the quantitative contribution of air pollution sources based on the chemical information (128 samples and 25 chemical species). Through a case study of the PMF modeling for the PM-10 aerosols. the total of 11 factors were determined. The multiple linear regression analysis between the observed PM-10 mass concentration and the estimated G matrix had been performed following the FPEAK test. Finally the regression analysis provided source profiles (scaled F matrix). So, 11 sources were qualitatively identified, such as secondary aerosol related source, soil related source, waste incineration source, field burning source, fossil fuel combustion source, industry related source, motor vehicle source, oil/coal combustion source, non-ferrous metal source, and aged sea- salt source, respectively.ively.y.

• 대기
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• 제22권1호
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• pp.73-85
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• 2012

The collision efficiency data for collision between graupel or hail particles and cloud drops that take into account the differences of particle density are applied to the Takahashi cloud model. The original setting assumes that graupel or hail collision efficiency is the same as that of the cloud drops of the same volume. The Takahashi cloud model is run with the new collision efficiency data and the results are compared with those with the original. As an initial condition, a thermodynamic profile that can initiate strong convection is provided. Three different CCN concentration values and therefore three initial cloud drop spectra are prescribed that represent maritime (CCN concentration = 300 $cm^{-3}$), continental (1000 $cm^{-3}$) and extreme continental (5000 $cm^{-3}$) air masses to examine the aerosol effects on cloud and precipitation development. Increase of CCN concentration causes cloud drop sizes to decrease and cloud drop concentrations to increase. However, the concentration of ice particles decreases with the increase of CCN concentration because small drops are difficult to freeze. These general trends are well captured by both model runs (one with the new collision efficiency data and the other with the original) but there are significant differences: with the new data, the development of cloud and raindrop formation are delayed by (1) decrease of ice collision efficiency, (2) decrease of latent heat from riming process and (3) decrease of ice crystals generated by ice multiplication. These results indicate that the model run with the original collision efficiency data overestimates precipitation rates.

• 한국대기환경학회지
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• 제19권1호
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• pp.93-100
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• 2003

본 연구에서는 세가지 통계적 기법을 적용하여 고산에서 측정한 TSP (Total Suspended Particle) 농도 특성을 해석하였다. 우선 황사와 비황사시의 평균농도를 비교하는 t-검정의 기본가정을 점검하였다. 모집단을 정규분포화 하기 위해 당량농도를 Log 변환하였고 이로써 1992~1999년 봄철 황사시 평균농도가 비황사시 평균농도보다 높은 이온 성분은 NH$_4$$^{+}$ 뿐임을 확인하였다. 통계적 검정을 수행함에 있어서 기본 가정을 확인하는 것은 중요한 과정이다. 또한 봄철에 집중되어 있는 TSP측정기간이 평균값에 미치게 될 영향을 제거하기 위해 측정일수를 유사하게 맞추었다. 측정일수를 맞추어 산정한 평균값과 측정일수가 다른대로 산정한 평균값을 비교해본 결과, 기간별 측정일수가 다름은 평균값에 영향을 미치나 큰 변화는 보이지 않았다. 마지막으로 비모수 통계기법을 이용해 nss-SO$_4$$^{2-}$ NO$_3$$^{-}$ 과 S/N 비의 경향성을 분석해본 결과, nss-SO$_4$$^{2-}$ 의 경우 통계적으로 그 경향성은 나타나지 않고 NO$_3$$^{-}$만이 증가경향을 나타내었으며, 따라서 증가하는 경향성을 보인 S/N 비는 NO$_3$$^{-}$ 에 의한 감소의 경향을 나타냄을 통계 적으로 확인하였다.

• 한국대기환경학회지
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• 제14권6호
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• pp.577-588
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• 1998

Polycyclic aromatic hydrocarbons (PAHs) are products of incomplete combustion and, in urban area atmosphere, are mainly traffic or heating in origin. Size-segregated aerosol samples were collected on the Eixth story of Shinchon on the Yonsei campus, using a high-volume cascade impactor, between August 1994 and September 1995. Ten PAHs were analyzed by GC/MSD. The size distribution of PAH-containing particulates followed approximately a log-normal relationship with the majority of PAH content associated with particles below 3.0mm. PAHs concentration in submicron particles increased during the winter months. The Mass Median Diameter (MMD) value of annual particulates in the heavy traffic area of Shinchon shows about 1.6 pm. The MMD values of air particulate in winter were the lowest values and similar to that in summer, while MMD values of seasonal PAHs were generally lower than 1.0 pm. Among the PAHs, MMD values of PAHs with the more than 5 benzen ring were averagely lower than those with 4 benzin rings. Especially MMD's of dibenzo (a, h) anthracene in winter was clearly lower than in summer. This reason may be caused by fuels used for heating. In this area, 50∼80% PAHs mass was particles smaller than 1.0mm aerodynamic diameter in size range, and the MMD values of PAHs lower than those of other country's area.

• Asian Journal of Atmospheric Environment
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• 제4권3호
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• pp.189-197
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• 2010

An orchestrated attempt was made to analyze samples of bulk and individual particulate matters (PM) collected at the Gosan ground-based station on the west coast of Jeju, Korea. A two-stage filter pack sampler was operated to collect particles in both large (> $1.2\;{\mu}m$) and small size fractions (< $1.2\;{\mu}m$) between the Asian dust (hereafter called "AD") storm event and non-Asian dust period. Elemental components in bulk and individual particles were determined by PIXE and synchrotron XRF analysis systems, respectively. To assess the transport pathways of air parcels and to determine the spatial distribution of PM, the backward trajectories of the Meteorological Data Explorer (Center for Global Environmental Research, 2010) and the NOAA's HYSPLIT dispersion-trajectory models were applied. In line with general expectations, Si and other crustal elements in large size particles showed considerably higher mass loading on AD days in comparison with non-AD days. Computation of the crustal enrichment factors [(Z/Si)$_{particle}$/(Z/Si)$_{desert}$ sand] of elements in large size particles (> $1.2\;{\mu}m$) allowed us to estimate the source profile and chemical aging of AD particles as well as to classify the soil-origin elements. On the basis of a single particle analysis, individual AD particles are classified into three distinct groups (neutralized mineral particles, S-rich mineral particles, and imperfectly neutralized particles).

• 한국대기환경학회지
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• 제24권4호
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• pp.404-414
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• 2008

A Transient Differential Mobility Particle Spectrometer (TR-DMPS) with a short response time was recently developed to monitor high concentration of ultrafine particles emitted from vehicles. To investigate the availability of the TR-DMPS for monitoring transient roadside aerosols, the number size distribution of ultrafine particles was monitored at the Cheongnyangni roadside in Seoul on March 23, 2007 together with a Scanning Mobility Particle Sizer (SMPS). The roadside aerosols were monitored every 5 min and 0.1 sec by using the SMPS and the TR-DMPS, respectively. The concentration of ultrafine particles at the roadside was highly fluctuated for a short duration. From the comparison of particle number concentrations and size distributions between two instruments, it was confirmed that the SMPS provided fairly good time-averaged number size distribution although it did not follow rapid change of particle number concentration at the roadside. The TR-DMPS quickly responded to a rapid change of particle number concentration due to abrupt traffic flow. However, the TR-DMPS frequently showed electrical noise events, resulting in underestimated particle contamination. A more stable operation of the TR-DMPS is needed in application of roadside aerosol monitoring.