• 한국환경과학회지
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• 제16권5호
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• pp.533-539
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• 2007

The research was conducted to simulate and interpret the change of $PM_{10}$ profile by Asian dust using the CALPUFF modeling system for the period April 6 through 18, 2001. The results, which are represented a daily variation of $PM_{10}$ concentration before and after Asian dust, was located between a minimum concentration of $50{\mu}g/m^3$ and a maximum concentration of $100{\mu}g/m^3$, Most concentration peaks in the $PM_{10}$ profile were shown within a level below 500 m and had a pattern that rapidly increased up the peak and decreased after the peak to 1000 m. Even though the shapes of the vertical profile during Asian dust days were similar to non-Asian dust days, no rapid change vertically was observed. In particular, the vertical profile on 1200 LST and 1800 LST was noticeably shifted to the higher concentrations, which means $PM_{10}$ in the atmosphere was changed into a vertically and horizontally heterogeneous form under the Asian dust event. Finally, it is con-firmed that the simulation result from CALPUFF might schematically sketched atmospheric $PM_{10}$ profiles and their change by Asian dust throughout the comparison with profiles of aerosol extinction coefficients, which were acquired from Lidar measurement at KGAWO.

• 한국대기환경학회지
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• 제25권4호
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• pp.325-338
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• 2009

National parks provide recreation, health, and science to human being. The provision of beautiful landscape view of the national park improves an economic and social phase of a nation. However, visibility impairment frequently occurred in the national park area of Gyeongju. The purpose of this study is to investigate the physical and the chemical characteristics of visibility reduction observed at the national park area of Gyeongju. Optical, chemical, meteorological characteristics and scenic monitoring were performed at the visibility monitoring station of Gyeongju University located at the Seoak section of Gyeongju national park from April 28 to May 9, 2008. Light extinction, light scattering, and light absorption coefficients were continuously measured using a transmissometer, a nephelometer, and an aethalometer, respectively. In order to investigate the impact of aerosol chemistry on visibility impairment, size-resolved aerosols were collected at intervals of 2-hour (from 8 A.M. to 6 P.M.) and 14-hour (from 6 P.M. to 8 A.M.) interval each sampling day. The average light extinction coefficient and the average visual range were measured to be $270{\pm}135\;Mm^{-1}$ and $14.5{\pm}6.3\;km$ during the intensive monitoring period, respectively. It was revealed that sulfate particle was the largest contributor to the light extinction under hazy condition. Organic mass accounted for about 26% of the average light extinction. The mass extinction efficiencies for $PM_{1.0}$, $PM_{2.5}$, and $PM_{10}$ were estimated to be 9.0, 4.7, and $2.7\;m^2\;g^{-1}$ under the consideration of water growth function of hygroscopic aerosols, respectively.

• Asian Journal of Atmospheric Environment
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• 제6권4호
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• pp.275-280
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• 2012

To understand the effect of aerosols on the growth and physiological conditions of trees in forests, it is important to know the state of aerosols that are deposited on the surface of the leaves or needles. In this study, we developed methods of visualization of submicron-sized aerosols that were artificially deposited from the gas-phase or liquid phase onto tree leaves or needles in trees. Firstly, we used field-emission scanning electron microscopy (FE-SEM) to observe black carbon (BC) particles that were artificially sprayed onto the leaves or needles. The distribution of BC particles deposited on the leaves and needles were distinguished based on the size and morphological features of the particles. The distribution and agglomerates size of BC particles differed between two spraying methods of BC particles employed. Secondly, we tried to visualize gold (Au) particles that were artificially sprayed onto the leaves using energy dispersive X-ray spectrometry (EDX) coupled to FE-SEM. We detected the Au particles based on the characteristic X-ray spectrum, which was secondarily generated from the Au particles. In contrast to the case of BC particles, the Au particles did not form agglomerates and were uniformly distributed on the leaf surfaces. The present results show that our methods provide useful information of adsorption and/or behavior of fine particles at the submicron level on the surface of the leaves.

• Asian Journal of Atmospheric Environment
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• 제12권1호
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• pp.78-86
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• 2018

Filter-based sampling techniques are the conventional way to collect particulate matter, but particles collected and entangled in the filter fibers are difficult to be removed and thus not suited for the following cell- and animal-based exposure experiments. Collecting aerosol particles in powder form using a cyclone instead of a filter would be a possible way to solve this problem. We developed a hybrid virtual-impactor/cyclone high-volume fine and coarse particle sampler and assessed its performance. The developed system achieved 50% collection efficiency with components having the following aerodynamic cut-off diameters: virtual impactor, $2.4{\mu}m$; fine-particle cyclone, $0.18-0.30{\mu}m$; and coarse-particle cyclone, $0.7{\mu}m$. The virtual impactor used in our set-up had good $PM_{2.5}$ separation performance, comparable to that reported for a conventional real impactor. The newly developed sampler can collect fine and coarse particles simultaneously, in combination with exposure testing with collected fine- and coarse-particulate matter samples, should help researchers to elucidate the mechanism by which airborne particles result in adverse health effect in detail.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E4호
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• pp.203-213
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• 2002

Receptor modeling is one of statistical methods to achieve reasonable air pollution strategies. In order to maintain and manage ambient air quality, it is necessary to identify sources and to apportion its sources for ambient particulate matters. The main purpose of the study was to survey seasonal trends of inorganic elements in the coarse and fine particles. Second, this study has attempted emission sources qualitatively by a receptor method, the PMF mo-del. After that. both PMF (positive matrix factorization) model and TTFA (target transformation factor analysis) model were applied to compare and to estimate mass contribution of coarse and fine particle sources at the receptor. A total of 138 sets of samples was collected from 1989 to 1996 by a low volume cascade impactor with 9 size fraction stages at Kyung Hee University in Korea. Sixteen chemical species (Si, Ca, Fe, K, Pb, Na, Zn, Mg, Ba, Ni, V, Mn, Cr, Br, Cu. Co) were characterized by XRF. The study result showed that the weighted arithmetic mean of coarse and fine particles were 51.3 and 54.4 $\mu\textrm{g}$/㎥, respectively. Contribution of both particle fractions were esti-mated using TTFA and PMF models. The number of estimated sources was seven according to TTFA model and 8 according to PMF model. Comparison of TTFA and PMF revealed that both methodologies exhibited similar trends in their contribution pattern. However, large differences between contributions were observed in some sour-ces. The results of this study may help to suggest control strategies in local countries where known source profiles do not exist.

• Asian Journal of Atmospheric Environment
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• 제7권4호
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• pp.217-226
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• 2013

The collection of TSP and $PM_{2.5}$ aerosols has been made at the Gosan Site of Jeju Island during 2008-2011, and their ionic and elemental species were analyzed, in order to examine the seasonal variation and characteristics of aerosol compositions. The anthropogenic components ($NH_4{^+}$, $nss-SO_4{^{2-}}$, $NO_3{^-}$, S, Zn, Pb) and the soil components ($nss-Ca^{2+}$, Al, Fe, Ca) showed high concentrations in spring as the prevailing westerly wind, but the concentrations of the sea-salt components ($Na^+$, $Cl^-$) were high in winter. In TSP, the neutralization by $NH_3$ increased in summer, but the neutralization by $CaCO_3$ increased in spring and fall seasons. The organic acids ($HCOO^-$, $CH_3COO^-$) contributed to the acidification of the aerosols by only 5.0%, so the acidification could be mostly contributed by the inorganic acids ($SO_4{^{2-}}$, $NO_3{^-}$). From the examination of the source origins by factor analysis, the compositions of TSP were influenced by the order of soil > anthropogenic > marine, on the other hand, those of $PM_{2.5}$ were by the order of anthropogenic > marine > soil. The backward trajectory analyses showed that the concentrations of $NH_4{^+}$, $nss-SO_4{^{2-}}$, $NO_3{^-}$ and $nss-Ca^{2+}$ increased highly when the air masses had moved from China continent into Gosan area of Jeju Island.

• 한국대기환경학회지
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• 제22권5호
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• pp.535-553
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• 2006

2003년 12월 '수도권 대기환경 개선에 관한 특별법'이 국회를 통과하면서, 서울을 포함한 수도권 대기에서 미세먼지 농도를 저감하는 것을 주요 목표로 하는 '수도권 대기환경관리 기본계획'이 수립되었다. 효과적인 미세먼지 저감 대책을 수립하기 위해서는 정확한 추이와 현황, 그리고 주요 기여원을 알아야만 한다. 이 연구에서는 2006년 9월까지 국내외 학술지와 학술대회 등에서 발표된 연구 결과를 종합적으로 검토, 분석하여 서울 대기의 미세먼지에 대해 (1)변화 추이를 파악하고, (2)농도에 영향을 미치는 주요 변수는 무엇인지를 찾고자 하였다. 아황산가스, 미세먼지 등의 대기환경기준물질 농도와 체감 대기오염의 지표인 시정의 지난 20여 년간의 변화를 검토한 결과 서울의 대기환경은 1990년 이후 개선되고 있음을 알았다. 그러나 서울의 미세먼지 관련 대기환경은 아직 우리나라 다른 대도시나 외국의 대도시에 비해 미세먼지 질량 농도나, 시정, 먼지의 화학조성 등 여러 면에서 나쁘다. 서울 대기의 미세먼지 농도에 영향을 미치는 주요 인자는 자체에서의 배출, 반응에 의한 생성, 외부로부터의 유입 세 가지이다. 현재의 측정 자료는 서울 대기의 미세먼지의 화학조성의 추이를 이해하기에 충분하지 않아, 외부로부터의 장거리이동과 반응에 의한 생성을 구분하기 힘들다. 그럼에도 불구하고, 측정 자료와 모사 결과를 종합하면 서울의 경우에는 배출과 외부로부터의 유입만큼이나 반응에 의한 생성의 영향이 큰 것으로 나타났다. 이는 서울의 미세먼지 농도를 줄이기 위해서는 직접 배출을 줄이는 것도 중요하지만, 광화학반응에 의한 생성과 외부에서의 유입을 줄이는 것도 중요함을 의미한다. 보다 효과적인 미세먼지 저감대책을 수립하기 위해서는 시공간적으로 대표성 있는 미세먼지 성분 분석 결과가 필요함을 다시 한 번 확인하였다.

• 한국대기환경학회지
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• 제22권6호
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• pp.863-875
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• 2006

Intensive visibility monitoring was conducted to investigate physical and chemical characteristics of visibility impairment by airborne pollen. Light attenuation coefficients were optically measured by a transmissometer, a nephelometer, and an aethalometer. Elemental, ionic, and carbonaceous species were chemically analyzed on the filters collected by $PM_{2.5}$ and $PM_{10}$ samplers. Aerosol size distribution was analyzed using a cascade impactor during airborne pollen period. Airborne pollen count was calculated using a scanning electron microscope. Airborne pollen was emitted into the atmosphere in springtime and funker degraded visibility through its scattering and absorbing the light. Average light extinction coefficient was measured to be $211{\pm}36Mm^{-1}$ when airborne pollen was not observed. But it increased to $459{\pm}267Mm^{-1}$ during the airborne pollen period due to increase of average $PM_{2.5}$ and $PM_{10}$ mass concentration and relative humidity and airborne pollen count concentration for $PM_{10}$, which were measured to be $46.5{\pm}29.1{\mu}g\;m^{-3},\;97.0{\pm}41.7{\mu}g\;m^{-3},\;54.1{\pm}11.6%$, and $68.2{\pm}89.7m^{-3}$, respectively. Average light extinction efficiencies for $PM_{2.5}$ and $PM_{10}$ were calculated to be $5.9{\pm}0.9$ and $4.5{\pm}0.8m^2 g^{-1}$ during the airborne pollen period. Light extinction efficiency for $PM_{10}$ increased further than that for $PM_{2.5}$. The average light extinction budget by airborne pollen was estimated to be about 24% out of the average measured light extinction coefficient during the airborne pollen period.

• 한국대기환경학회지
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• 제15권1호
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• pp.23-32
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• 1999

Deposition is one of the important removal mechanisms for the ambient aerosol, and it also leads to adverse environmental and economic impacts. The purpose of this study was to investigate chemical compositions and spatial distributions of fall-out aerosols. A total number of 340 samples were collected at 35 sampling sites in Suwon area from January to November, 1996. Twelve inorganic elements (Al, Ba, Cd, Cr, K, Pb, Sb, Zn, Cu, Fe, Ni, and V) and eight ionic components ($F^-$, Cl, $NO_3^-$, $SO_4^{2-}$, $Na^+$, $NH_4^+$, $Mg^{2+}$, and $Ca^{2+}$) were analyzed by AAS and IC, respectively. The monthly variation showed that the flux of fall-out particles was increased in the spring season(March, April, and May) and decreased from August to October. Arithmetic mean flux of fall-out particles was 176.8 kg/$ extrm{km}^2$/day during the study period. The fluxes of each chemical species were $SO_4^{2-}$ 12.414, $Ca^{2+}$ 7.369, $NO_3^-$ 5.812, $Cl^-$ 3.566, $NH_4^+$ 3.176, Fe 3.107 kg/$\textrm{km}^2$/day, and so on. By using a kriging analysis, spatial distribution pattern of those fluxes was intensively studied. Total fluxes estimated in Suwon city were 8424.72t/y of fall-out particles, 519.27t/y of $SO_4^{2-}$, 336.79t/y of $Ca^{2+}$,267.34 t/y of $NO_3^+$, 155.36t/y of $Cl^-$, 147.79t/y of Fe.

• 한국대기환경학회지
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• 제15권1호
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• pp.53-61
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• 1999

Acid aerosol and gas concentrations ($SO_4^{2-}$, $NO_3^-$, $HNO_3$, $SO_2$, and $NH_3$) were measured at Chunchon and Seoul, Korea using filter pack method during one year from October 1996 to september 1997. The samples were collected during 24 hours every Wednesday in a week from 10 A.M. with 10$\ell$/min of sample flow. Concentration of $HNO_3$, $SO_2$ and $NH_3$ gases showed typical seasonal variation. The $HNO_3$ showed the highest in summer and annual mean concentrations were 0.42 ppb and 0.57 ppb at Chunchon and Seoul, respectively. The $SO_2$ showed the highest in winter and annual mean concentration was 5.59 ppb at Chunchon. The $NH_3$ showed the highest in early summer and annual mean concentration were 5.15 ppb and 6.28 ppb at Chunchon and Seoul, respectively.