• Title/Summary/Keyword: Atmospheric aerosol

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Characterization of Individual Atmospheric Aerosols Using Quantitative Energy Dispersive-Electron Probe X-ray Microanalysis: A Review

  • Kim, Hye-Kyeong;Ro, Chul-Un
    • Asian Journal of Atmospheric Environment
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    • v.4 no.3
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    • pp.115-140
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    • 2010
  • Great concerns about atmospheric aerosols are attributed to their multiple roles to atmospheric processes. For example, atmospheric aerosols influence global climate, directly by scattering or absorbing solar radiations and indirectly by serving as cloud condensation nuclei. They also have a significant impact on human health and visibility. Many of these effects depend on the size and composition of atmospheric aerosols, and thus detailed information on the physicochemical properties and the distribution of airborne particles is critical to accurately predict their impact on the Earth's climate as well as human health. A single particle analysis technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA) that can determine the concentration of low-Z elements such as carbon, nitrogen and oxygen in a microscopic volume has been developed. The capability of quantitative analysis of low-Z elements in individual particle allows the characterization of especially important atmospheric particles such as sulfates, nitrates, ammonium, and carbonaceous particles. Furthermore, the diversity and the complicated heterogeneity of atmospheric particles in chemical compositions can be investigated in detail. In this review, the development and methodology of low-Z particle EPMA for the analysis of atmospheric aerosols are introduced. Also, its typical applications for the characterization of various atmospheric particles, i.e., on the chemical compositions, morphologies, the size segregated distributions, and the origins of Asian dust, urban aerosols, indoor aerosols in underground subway station, and Arctic aerosols, are illustrated.

Opto-Chemical Characteristics of Visibility Impairment Using Semi-Continuous Aerosol Monitoring in an Urban Area during Summertime (에어로졸의 준실시간 관측에 의한 여름철 도시지역 시정 감쇄 현상의 광ㆍ화학적인 특성 분석)

  • 김경원;김영준
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.6
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    • pp.647-661
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    • 2003
  • For continuous monitoring of atmospheric visibility in the city of Kwanaju, Korea, a transmissometer system consisting of a transmitter and a receiver was installed at a distance of 1.91 km across the downtown Kwanaju. At the transmitter site an integrating nephelometer and an aethalometer were also installed to measure the scattering and absorption coefficients of the atmosphere, respectively. At the receiver site. an URG PM$_{2.5}$ cyclone sampler and an URG-VAPS (Versatile Air Pollutant Sampler) with three filter packs and two denuders were used to collect both PM$_{2.5}$ and PM$_{10}$ samples at a 2-hour or 12-hour sampling interval for aerosol chemical analysis. Sulfate, organic mass by carbon (OMC), nitrate, elemental carbon (EC) components of fine aerosol were the major contributors to visibility impairment. Diurnal variation of visibility during best-case days showed rapid improvement in the morning hours, while it was delayed until afternoon during the worst-case days. Aerosol mass concentration of each aerosol component for the worst-case was calculated to be 11.2 times larger than the best-case for (NH$_4$)$_2$SO$_4$(NHSO), 19.0 times for NH$_4$NO$_3$ (NHNO), 2.2 times for OMC, respectively. Also result shows that elemental carbon and fine soil (FS) were 3.7 and 2.2 times more than those of best-case. respectively- Sum of total contributions of wet NHSO and NHNO to light extinction was calculated to be 301 Mm$^{-1}$ for the worst-case. However, sum of contributions by dry NHSO and NHNO was calculated to be 123 Mm$^{-1}$ for the best case. Mass extinction efficiencies of fine and coarse particles were calculated to be 5.8$\pm$0.3 $m^2$/g and 1.8$\pm$0.1 $m^2$/g, respectively.ely.

Spatial Analysis of Major Atmospheric Aerosol Species Using Earth Observing Satellite Data (지구관측 위성자료를 이용한 주요 대기 에어러솔 성분의 공간분포 분석)

  • Lee, Kwon-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.2
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    • pp.109-127
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    • 2011
  • Atmospheric aerosols, small particles in the atmosphere, are one of the important parameters in climate change and human health. Additionally, accurate estimates of aerosol species are increasingly important in environmental impact assessment studies. Recent advances in global satellite remote sensing provide powerful tool for air quality monitoring. This study explores the potential usage of satellite derived data such as atmospheric aerosols for air quality monitoring as well as climate change study. The objectives of this study is to understand the general features of the global distribution of type dependent aerosols. A detailed spatio-temporal variability of the each different satellite dataset shows the variation of the global zonal average and specific geographical regions where the strong emission sources are located. Especially, significantly large aerosol amounts are observed in Asia and Africa because of the desert dust storm, anthropogenic and biomass burning emissions.

Behaviors of Inorganic Components in Atmospheric Aerosols on the Yellow Sand Phenomena (황사현상시 대기에어로졸 중 무기물질의 동태)

  • 이민희;한의정;신찬기;한진석;김상균
    • Journal of Korean Society for Atmospheric Environment
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    • v.9 no.3
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    • pp.230-235
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    • 1993
  • The atmospheric aerosol samples during the Yellow Sand Phenomena in April 1993 were analyzed, and they were compared with those during the normal time. The conclusions are as follows: 1) TSP concentrations in the case of Yellow Sand Phenomena appeared to be 2.2times higher than those of normal conditions. 2) The concentration of aerosols; Inorganic components of soil-originated elements (Ca, Fe, Mn, Mg, K) during the Yellow Sand Phenomena were measured to be 1.9-2.1times higher than those during normal time. 3) During the Yellow Sand Phenomena the EF values of soil-originated metal contents except for elements Cd, Ni, Pb, Zn in the atmospheric aerosol were close to unity. 4) The concentrations of $Ca^{2+}, SO_4^{2-}, F^-$ in water soluble ionic components were higher than those during the normal time. 5) Washout factor by rain fall during the Yellow Sand Phenomena were estimated to 1268. 6) During the Yellow Sand Phenomina average deposition was 37.8ton/$km^2$.

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Development of Aerosol Model Using Moment Method and Validation by Experiments (모멘트 방법을 이용한 에어로즐 모델의 개발과 실험을 통한 검증)

  • Kim Gyeong-A;Kim Dae-Seong;Park Seong-Hun;Gwon Sun-Park;Lee Gyu-Won
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.11a
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    • pp.385-386
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    • 2002
  • Many important physical properties of natural or man-made aerosol particles such as light scattering, electrostatics charges, and toxicity, as well as their behavior involving physical processes like diffusion and thermophoresis depend strongly on their size distribution. Important aerosol behavior mechanisms affecting the size distribution of aerosol particles include condensation, deposition, and coagulation. (omitted)

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Sensitivity Analysis by Using Global Imager for Retrieval of Biomass Burning Aerosols

  • Lee, Hyun-Jin;Kim, Jae-Hwan
    • Asian Journal of Atmospheric Environment
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    • v.5 no.2
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    • pp.79-85
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    • 2011
  • The purpose of this study is to evaluate the strength of the near-UV wavelength of 380 nm relative to visible and near-IR bands, and to find the suitable wavelength for detecting aerosols by using the Global Imager (GLI) sensor aboard the Advanced Earth Observing Satellite-II (ADEOS-II). Sensitivity analysis is performed for the retrieval of biomass burning aerosols by employing the radiative transfer model Rstar5b. It is determined that background surface reflectance in the blue band is similar to that in the near-UV band, and that wavelengths in the blue bands are more sensitive to the Aerosol Optical Thickness (AOT) than wavelengths in the near-UV band. The Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI) is used in the indirect method used for aerosol retrieval, and the wavelength pair 380 nm and 460 nm is determined to be the most sensitive to the AOT. The results of this study suggest that wavelengths in the blue bands are suitable for detecting biomass burning aerosols over the Korean peninsula.

Exploiting GOCI-II UV Channel to Observe Absorbing Aerosols (GOCI-II 자외선 채널을 활용한 흡수성 에어로졸 관측)

  • Lee, Seoyoung;Kim, Jhoon;Ahn, Jae-Hyun;Lim, Hyunkwang;Cho, Yeseul
    • Korean Journal of Remote Sensing
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    • v.37 no.6_1
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    • pp.1697-1707
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    • 2021
  • On 19 February 2020, the 2nd Geostationary Ocean Color Imager (GOCI-II), a maritime sensor of GEO-KOMPSAT-2B, was launched. The GOCI-II instrument expands the scope of aerosol retrieval research with its improved performance compared to the former instrument (GOCI). In particular, the newly included UV band at 380 nm plays a significant role in improving the sensitivity of GOCI-II observations to the absorbing aerosols. In this study, we calculated the aerosol index and detected absorbing aerosols from January to June 2021 using GOCI-II 380 and 412 nm channels. Compared to the TROPOMI aerosol index, the GOCI-II aerosol index showed a positive bias, but the dust pixels still could be clearly distinguished from the cloud and clear pixels. The high GOCI-II aerosol index coincided with ground-based observations indicating dust aerosols were detected. We found that 70.5% of dust and 80% of moderately-absorbing fine aerosols detected from the ground had GOCI-II aerosol indices larger than the 75th percentile through the whole study period.

Modelling of Aerosol Vertical Distribution during a Spring Season at Gwangju, Korea

  • Shin, Sung-Kyun;Lee, Kwon-Ho
    • Asian Journal of Atmospheric Environment
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    • v.10 no.1
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    • pp.13-21
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    • 2016
  • The vertical distributions of aerosol extinction coefficient were estimated using the scaling height retrieved at Gwangju, Korea ($35.23^{\circ}N$, $126.84^{\circ}E$) during a spring season (March to May) of 2009. The aerosol scaling heights were calculated on a basis of the aerosol optical depth (AOD) and the surface visibilities. During the observation period, the scaling heights varied between 3.55 km and 0.39 km. The retrieved vertical profiles of extinction coefficient from these scaling heights were compared with extinction profile derived from the Light Detection and Ranging (LIDAR) observation. The retrieve vertical profiles of aerosol extinction coefficient were categorized into three classes according to the values of AODs and the surface visibilities: (Case I) the AODs and the surface visibilities are measured as both high, (Case II) the AODs and the surface visibilities are both lower, and (Others) the others. The averaged scaling heights for the three cases were $3.09{\pm}0.46km$, $0.82{\pm}0.27km$, and $1.46{\pm}0.57km$, respectively. For Case I, differences between the vertical profile retrieved from the scaling height and the LIDAR observation was highest. Because aerosols in Case I are considered as dust-dominant, uplifted dust above planetary boundary layer (PBL) was influenced this discrepancy. However, for the Case II and other cases, the modelled vertical aerosol extinction profiles from the scaling heights are in good agreement with the results from the LIDAR observation. Although limitation in the current modelling of vertical structure of aerosols exists for aerosol layers above PBL, the results are promising to assess aerosol profile without high-cost instruments.

Seasonal Variations of Chemical Composition and Optical Properties of Aerosols at Seoul and Gosan (서울과 고산의 에어로졸 화학성분과 광학특성의 계절변화)

  • Lee, S.;Ghim, Y.S.;Kim, S.W.;Yoon, S.C.
    • Journal of Korean Society for Atmospheric Environment
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    • v.24 no.4
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    • pp.470-482
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    • 2008
  • Seasonal variations of chemical composition and optical properties of aerosols at Seoul and Gosan were investigated using the ground-based aerosol measurements and an optical model calculation. The mass fraction of elemental carbon was $8{\sim}17%$, but its contribution on light absorption was high up to $29{\sim}48%$ in Seoul. In Gosan, the contribution of water soluble aerosols on aerosol extinction was $83{\sim}94%$ due to the high mass fraction of these particles in the range of $56{\sim}88%$. Model calculation showed that the water holding capacity of aerosols was larger in Gosan than in Seoul because of higher relative humidity and temperature along with abundant water soluble aerosols. Difference between measured and calculated aerosol optical depths was the highest in summer. This was because aerosol optical depth calculated from ground-based measurements could not consider aerosol loadings at high altitude in spite of high column-integrated aerosol loadings observed by Sun photometer. Although hygroscopic growth was expected to be dominant in summer, the mass concentration of water soluble aerosols was too low to permit this growth.

Estimation of Aerosol Vertical Profile from the MODIS Aerosol Optical Thickness and Surface Visibility Data (MODIS 에어러솔 광학두께와 지상에서 관측된 시정거리를 이용한 대기 에어러솔 연직분포 산출)

  • Lee, Kwon-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.16 no.2
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    • pp.141-151
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    • 2013
  • This study presents a modeling of aerosol extinction vertical profiles in Korea by using the Moderate Resolution Imaging Spectro-radiometer(MODIS) derived aerosol optical thickness(AOT) and ground based visibility observation data. The method uses a series of physical equations for the derivation of aerosol scale height and vertical profiles from MODIS AOT and surface visibility data. The modelled results under the standard atmospheric condition showed small differences with the standard aerosol vertical profile used in the radiative transfer model. Model derived aerosol scale heights for two cases of clean(${\tau}_{MODIS}=0.12{\pm}0.07$, visibility=$21.13{\pm}3.31km$) and hazy atmosphere(${\tau}_{MODIS}=1.71{\pm}0.85$, visibility=$13.33{\pm}5.66km$) are $0.63{\pm}0.33km$ and $1.71{\pm}0.84km$. Based on these results, aerosol extinction profiles can be estimated and the results are transformed into the KML code for visualization of dataset. This has implications for atmospheric environmental monitoring and environmental policies for the future.