• 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).

• Journal of Korean Society for Atmospheric Environment
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• 제16권E호
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• pp.19-27
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• 2000

Particle Induced X-ray Emission (PIXE) and Elemental Analysis Syztem (EAS) were applied to the investiga-tion of the Characteristics and sources of wintertime atmospheric aerosols in Seoul. Atmospheric aerosols were collected by both fine and coarse fractions using a two-stage filter pack sampler from Kon-Kuk university during the winter season of 1999. PIXE was applied to the analysis of the middle and heavy elements with atomic numbers greater than 14(Si) and EAS was applied to the measurement of the light elements such as H, C and N. The fact that 64.2% of mass of fine particles in Seoul consists of the light elements (N, C , and H) suggests that the measurement of light elements is extremely important. The average mass concentration is Seoul was 38.6$\mu\textrm{g}$m(sup)-3. Elements such as Ca, Fe, Mg, and Ti appeared to have very low Fine/Coarse ratios(0.1∼0.4), whereas che-mical components related to anthropogenic sources such as Br, V, Pb, and Zn were observed to accumulate in the fine fraction. In the Asian Dust Storm(ADS) event, the concentation of soil components increased dramatically. Reconstruction of the fine mass concentrations estimated by a newly revised simple model was fairly in good agreement with the measured ones. Source identification was attempted using the enrichment factor and Pearsons coefficient of correlation. The typical elements derived from each source could be classified by this method.

• Journal of Korean Society for Atmospheric Environment
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• 제20권E2호
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• pp.53-59
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• 2004

The roadway tunnels in urban areas give rise to problems such as a localized air pollution. Here, we report the results of a case study of an urban roadway tunnel measurement. The size-resolved particle sampling was carried out with a two 2-stage filter pack samplers and an Andersen impactor sampler at the center of Buk-Ak tunnel in November 2001. Particle Induced X-ray Emission (PIXE) was applied to determine the elemental composition of size-resolved particles divided into soluble and insoluble fractions. The Thermal/Optical Reflectance (TOR$^{(R)}$) method was also employed in analyzing of elemental carbon (EC) and organic carbon (OC). Mass concentrations of fine (< 1.2 ${\mu}{\textrm}{m}$) and coarse (> 1.2 ${\mu}{\textrm}{m}$) particles are 165 and 48 $\mu\textrm{g}$ m$^{-3}$ , respectively. Total elemental mass concentration (the sum of insoluble coarse, soluble coarse, insoluble fine, and soluble fine) is found to be 24$\mu\textrm{g}$ m$^{-3}$ and comprises only 11 % of total particle mass concentration. The concentrations of EC, OC, and mass show the clear dependency on particle size with the maximum between 0.1 and 0.43 ${\mu}{\textrm}{m}$ aerodynamic diameters. Total carbon (sum of EC and OC) accounts for approximately 70% of mass concentration.n.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.957-962
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• 2018

The gamma radiation shielding capability (GRSC) of two clay-materials (Ball clay and Kaolin)of Southwestern Nigeria ($7.49^{\circ}N$, $4.55^{\circ}E$) have been investigated by determine theoretically and experimentally the mass attenuation coefficient, ${\mu}/{\rho}(cm^2g^{-1})$ of the clay materials at photon energies of 609.31, 1120.29, 1173.20, 1238.11, 1332.50 and 1764.49 keV emitted from $^{214}Bi$ ore and $^{60}Co$ point source. The mass attenuation coefficients were theoretically evaluated using the elemental compositions of the clay-materials obtained by Particle-Induced X-ray Emission (PIXE) elemental analysis technique as input data for WinXCom software. While gamma ray transmission experiment using Hyper Pure Germanium (HPGe) spectrometer detector to experimentally determine the mass attenuation coefficients, ${\mu}/{\rho}(cm^2g^{-1})$ of the samples. The experimental results are in good agreement with the theoretical calculations of WinXCom software. Linear attenuation coefficient (${\mu}$), half value layer (HVL) and mean free path (MFP) were also evaluated using the obtained ${\mu}/{\rho}$ values for the investigated samples. The GRSC of the selected clay-materials have been compared with other studied shielding materials. The cognizance of various factors such as availability, thermo-chemical stability and water retaining ability by the clay-samples can be analyzed for efficacy of the material for their GRSC.

• Asian Journal of Atmospheric Environment
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• 제6권1호
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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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• 제11권3호
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• pp.176-183
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• 2017

Although it is well known that rain plays an important role in capturing air pollutants, its quantitative evaluation has not been done enough. In this study, the effect of raindrop size on pollutant scavenging was investigated by clarifying the chemical nature of individual size-resolved raindrops and their residual particles. Raindrops as a function of their size were collected using the raindrop collector devised by our oneself in previous study (Ma et al., 2000) during high atmospheric loading for $PM_{2.5}$. Elemental analyses of solid residues and individual residual particles in raindrops were subsequently analyzed by Particle Induced X-ray Emission (PIXE) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX), respectively. The raindrop number concentration ($m^{-2}h^{-1}$) tended to drastically decrease as the drop size goes up. Particle scavenging rate, $R_{sca.}$ (%), based on the actual measurement values were 38.7, 69.5, and 80.8% for the particles with 0.3-0.5, 0.5-1.0, and $1.0-2.0{\mu}m$ diameter, respectively. S, Ca, Si, and Al ranked relatively high concentration in raindrops, especially small ones. Most of the element showed a continuous decrease in concentration with increasing raindrop diameter. The source profile by factor analysis for the components of residual particles indicated that the rainfall plays a valuable role in scavenging natural as well as artificial particles from the dirty atmosphere.

• Asian Journal of Atmospheric Environment
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• 제6권2호
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• pp.73-82
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• 2012

This study was aimed to thoroughly estimate the characteristics of indoor particulate matter (PM) collected on subway platforms by the cooperative approach of semi-bulk and single particle analyses. The size-resolved PM and its number concentration were measured on the platform in a heavily traveled subway station in Fukuoka, Japan. Particle Induced X-ray Emission (PIXE) and micro-PIXE techniques were applied to the chemical analyses of semi-bulk and single particle, respectively. There was the close resemblance of timely fluctuation between PM number concentration and train service on the third basement floor (B3F) platform compared to the second basement floor (B2F) and its maximum level was marked in rush hour. Higher number counts in large particles ($>1{\mu}m$) and lower number counts in fine particles ($<1{\mu}m$) were shown on the platform compared to an above ground. PM2.5 accounted for 58.2% and 38.2 % of TSP on B3F and on B2F, respectively. The elements that were ranked at high concentration in size-resolved semi-bulk PM were Fe, Si, Ca, S, and Na. The major elements tending to have more elevated levels on B3F than B2F were Fe (4.4 times), Ca (17.3 times), and Si (46.4 times). Although concentrations were very low, Cr ($11.9ng\;m^{-3}$ on B3F, $2.4ng\;m^{-3}$ on B2F), Mn ($3.4ng\;m^{-3}$ on B3F, $0.9ng\;m^{-3}$ on B2F), and Pb ($0.6ng\;m^{-3}$ on B3F, $1.6ng\;m^{-3}$ on B2F) were detected from PM2.5. Individual PM was nearly all enriched in Fe with Si and Ca. Classifying and source profiling of the individual particles by elemental maps and particle morphology were tried and particles were presumably divided into four groups (i.e., train/rail friction, train-rail sparking, ballast/abrasive, and cement).

• Asian Journal of Atmospheric Environment
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• 제2권1호
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• pp.26-33
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• 2008

In order to fully understand the chemical properties of Asian dust particles, especially their transformation and aging processes, it is desirable to investigate the nature of original sands collected at local source areas in China. This study presents the detailed properties of sands collected at four different desert regions (Yinchuan, Wuwei, Dulan, and Yanchi) in China. Most of sands have irregular shape with yellowish coloration, whereas some of them show peculiar colors. The relative size distribution of sands collected at Yinchuan, Wuwei, and Dulan deserts exhibits monomodal with the maximum level between 200 and $300{\mu}$, whereas that of Yanchi desert is formed between 100 and $200{\mu}$. The mass concentration ratio of each element to that of Si (Z/Si) determined by PIXE analysis has a tendency towards higher Z/Si ratios for soil derived elements. It was possible to visually reconstruct the elemental maps on the surface of individual sands by XRF microprobe technique. In addition, the multielemental mass concentration could be quantitatively calculated for numerous spots of desert sands.

• 한국진공학회지
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• 제10권3호
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• pp.380-386
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• 2001

정밀가변슬릿과 자기사중극렌즈로 구성된 핵 마이크로프로브 (nuclear microprobe) 시스템을 일차행렬법을 이용한 빔광학 전산모사를 통해 설계하였으며, 제작된 시스템을 KIGAM 1.7 MV 탄뎀 반데그라프 가속기의 $30^{\circ}$ 빔라인에 설치하였다. X 및 Y축에 대한 역배율은 각각 25와 4.9로 계산되며, 3 MeV 양성자빔의 경우 최소 빔크기는 약 5 미크론, 빔전류는 약 1 nA 정도로 추산된다. PIXE, RBS, ERDA등 MeV 이온빔분석법과 이온빔 미세가공을 위해 다목적 8각형 표적함을 제작하였으며, 표적함은 X-선 및 하전입자검출기, 줌현미경, 파라데이컵, 4축 시료이송계 및 고진공계로 구성되어 있다. 현재 핵 마이크로프로브 시스템 성능 조사가 이루어지고 있으며, 자동화된 시료 이송 및 자료 처리 시스템이 설치되면 일상적인 마이크로 이온빔 분석이 가능해 질 것으로 예상된다.

• 한국환경보건학회지
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• 제36권1호
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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.