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Investigation of aged Asian dust particles by the combined use

Investigation of aged Asian dust particles by the combined use of quantitative ED-EPMA and ATR-FTIR imaging. Chul-Un Ro ( 盧 鐵 彦 ). Inha University, KOREA ( 仁荷大學校 ). airborne asbestos. indoor aerosols. Characterization. Development. SEM/EDX. TEM/EDX. polar aerosols.

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Investigation of aged Asian dust particles by the combined use

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  1. Investigation of aged Asian dust particles by the combined use of quantitative ED-EPMA and ATR-FTIR imaging Chul-Un Ro (盧 鐵 彦) Inha University, KOREA (仁荷大學校)

  2. airborne asbestos indoor aerosols Characterization Development SEM/EDX TEM/EDX polar aerosols marine aerosols Our works COMBINED APPLICATION OF SINGLEPARTICLE ANALYTICAL TECHNIQUES ▶ Characterization of various airborne aerosol particles ▶ Development of single particle analytical techniques urban aerosols Asian dust m-Raman imaging hygroscopic measurement ATR-FT-IR imaging

  3. Whyaerosol characterization? Atmospheric aerosol particles influenceecosystems, global climate change, human health, cultural heritage, …

  4. Single particle characterization • Ambient aerosols • = complex heterogeneous mixtures of natural and anthropogenic particles Production, growth, reaction, and removal of atmospheric aerosols – individually * better to apply single particle analytical techniques for the characterization of physicochemical properties of atmospheric aerosol particles

  5. Combined use of single particle analytical techniques for characterization of the same particle ensemble

  6. Long range transport of Asian dust (ex) Asian dust event occurred on Apr. 15, 1998

  7. Chemical modification of Asian dust during long range transport 1. Single-Particle Characterization of Four Asian Dust Samples Collected in Korea, Using Low-Z Particle EPMA, Environ. Sci. Technol., 39, 1409-1419 (2005) 2. Single-particle characterization of four aerosol samples collected in ChunCheon, Korea, during Asian Dust Storm events in 2002, J. Geophys. Res.,110, D23201 (2005) 3. Direct observation of nitrate and sulfate formations from mineral dust and sea-salts using low-Z particle EPMA, Atmos. Environ., 40, 3869-3880 (2006) 4. Single-particle characterization of aerosol samples collected before and during an Asian dust storm in Chuncheon, Korea, Atmos. Environ., 42, 8738–8746 (2008) 5. Elevated nitrogen-containing particles observed in Asian dust aerosol samples collected at the marine boundary layer of the Bohai Sea and the Yellow Sea, Atmos. Chem. Phys., 9, 6933-6947 (2009) 6. Investigation of the Chemical Mixing State of Individual Asian Dust Particles by the Combined Use of EPMA and Raman Microspectrometry, Anal. Chem., 84, 3145-3154 (2012) 7. Investigation of aged Asian dust particles by the combined use of quantitative ED-EPMA and ATR-FTIR imaging, Atmos. Chem. Phys., 13, 3463-3480 (2013)

  8. Single Particle Analytical Techniques ■ low-Z particle EPMA (Electron Probe X-ray Microanalysis) • Single particle analysis of (sub)micrometer particles with high resolution images and elemental X-ray analysis SEM/EDX (scanningelectron microscope/ energy-dispersive X-ray detector) Size, shape from secondary electron image Chemical compositions from X-ray spectrum

  9. Illustrative Example of Single Particle Analysis Using Low-Zparticle EPMA Na : N : O = 1 : 1 : 3 NaNO3 particle from NaCl + HNO3NaNO3 + HCl atomic conc. (%) N 17.2 O 56.8 Na 19.4 S 2.3 Cl 2.8 K 0.4 Ca 0.9 Nitrate-type particle atomic conc. (%) O 5.3 Na 45.5 Cl 49.2 Sea-salt-type particle Na : Cl = 1 : 1 genuine sea-salt particle

  10. Mg(NO3,SO4,Cl) Ca(CO3,NO3)/Aluminosilicates NaNO3 Ca(CO3,NO3 ,SO4)/FeOx Aluminosilicates (Ca,Mg)(CO3,NO3)/Aluminosilicates NaNO3 Cu Ca(NO3)2 Low-Z particleEPMA Asian dust * Chemical speciation of individual Asian dust particles based on their morphology and chemical compositions * Direct observation of their chemical modification during long range transport Exemplar secondary electron image of individual Asian Dust particles

  11. Source Region Source Region Characterization of Asian Dust (ES&T, 2005; JGR, 2005; AE, 2006) * Samplings (During Asian Dust Storms) - 2000: (A) March 7, (B) April 7 - 2001: (C) March 22, (D) May 17 - 2002: (E) March 21, (F) April 9, (G) April 17, (H) November 11 Overall relative abundances of significantly encountered particle types (F) April 9, 2002 (E) Mar. 21, 2002 Source Region D (D) May 17, 2001 (H) Nov. 11, 2002 Source Region H

  12. Low-Z particleEPMA Number of particles containing sulfate or nitrate due to atmospheric reactions of CaCO3, sea-salts, and K2CO3 for samples collected during Asian Dust storm events * nitrate formation : more favorable than sulfate formation * sea-salts : more reactive than CaCO3 particles * Understanding of heterogeneous reactions and their reactivity (Environ. Sci. Technol., 2005: J. Geophys. Res., 2005)

  13. Dual detectors Visible radiation Cassegrain system Motorized X-Y sample stage sample IR radiation Single Particle Analytical Techniques ■ ATR-FT-IR (Attenuated Total Reflectance FT-IR Spectrometry) imaging • the combination of microscopy with IR spectroscopy • Individual Particle Analysis * location : optical image * mineral type, functional groups, and crystal structure : IR spectrum Perkin-Elmer Spectrum 100 FT-IR spectrometer Perkin-Elmer Spotlight 400 FT-IR microscope X-Y stage

  14. Single Particle Analytical Techniques ■ The combined use of EPMA and ATR-FT-IR imaging for thesame individual particles of micrometer size • low-Z particle EPMA : size, shape, quantitative elemental concentrations • ATR-FT-IR imaging : mineral type, functional groups, molecular species, phase Antarctica aerosols (1) Genuine sea-salts (2) nss-sulfates by the oxidation of DMS emitted from phytoplanktons (ES&T, 2011)

  15. Asian Dust - Nov. 11, 2002 (A) Secondary electron image (SEI) before ATR-FT-IR imaging measurement; (B) visible light optical image; (C) ATR-FT-IR image; (D) SEI after ATR-FT-IR imaging measurement of the same 109 individual Asian Dust particles on Ag foil

  16. Asian Dust : morphology and chemical species 5. (Na,Mg)(NO3,NO2,SO4)/organic 23. (Na,K,Ca)(NO3,NO2,CO3,SO4,Cl)/organic/H2O 25. Ca(CO3,NO3)/montmorillonite/organic/H2O 26. cristobalite/Ca(CO3,NO3)/organic/H2O 22. montmorillonite/ Ca(CO3,NO3)/organic/H2O 28. Ca(CO3,NO3)/montmorillonite/ organic/H2O 27. (Na,Ca)(CO3,NO3)/quartz/ organic/H2O 24. pyrophyllite/ (K,Na)CO3 29. (Na,Ca)(NO3,NO2,Cl)/ organic/H2O 21. quartz 61. CaSO4 56. Ca-feldspar/ Ca(CO3,NO3)/organic/H2O 60. Na(NO3,NO2,SO4)/quartz 59. Ca(CO3,NO3,SO4)/ montmorillonite/organic/H2O 55. Ca(CO3,NO3)/Si-O/organic/H2O 62. amorphous calcium carbonate/organic/H2O 57. amorphous calcium carbonate/ organic/H2O

  17. 63. amorphous calcium carbonate,/ quartz/organic/H2O A Asian Dust : morphology and chemical species 58. amorphous calcium carbonate/ montmorillonite/organic/H2O 83. (Na,Mg)(NO3,NO2)/ organic 88. Al2O3/Ca(CO3,NO3,SO4)/ organic/H2O 82. Ca(CO3,NO3,SO4)/ montmorillonite/organic/H2O 84. montmorillonite/ quartz/FeOx/organic 87. quartz/(Mg,Ca)(CO3,NO3)/H2O 86. organic 79. Na(NO3,NO2)/organic 78. fly ash 80.CaSO4 85. Ca(CO3,NO3,SO4)/ organic/H2O 81. CaSO4 103. (Na,Mg)(NO3,NO2,SO4,Cl)/organic 105. Ca(CO3,NO3,SO4)/ organic/H2O 104. (Na,Mg,Ca)(NO3,NO2,CO3,SO4)/ Si-O/organic 102. Na(NO3,NO2,SO4)

  18. Asian Dust : Ca-containing [1] Particle #89 - (A) and (D)  CaCO3/montmollinolite/sulfate/elemental carbon; [2] Particle #62 - (B) and (E)  amorphous CaCO3/ sulfate/nitrate/H2O; [3] Particle #50 - (C) and (F)  Ca(SO4,NO3)/CaCO3/organic/chloride/H2O

  19. Asian Dust : NaNO3-containing [1] Particle #79 - (A) and (D)  crystalline NaNO3; [2] Particle #33 - (B) and (E)  crystalline NaNO3/sulfate/ organic/H2O; [3] Particle #54 - (C) and (F)  crystalline NaNO3/CaCO3/sulfate/montmorillonite/H2O

  20. Asian Dust : silicates (E) (D) [1] Particle #24 - (A) and (D)  crystalline muscovite/carbonate/organic; [2] Particle #40 - (B) and (E) montmorillonite/ carbonate/nitrate/ organic/H2O; [3] Particle #45 - (C) and (F)  K-feldspar/carbonate/nitrate/organic/H2O

  21. Asian Dust : miscellaneous [1] Particle #6 - (A) and (D)  water soluble secondary organic/(NH4)2SO4/H2O; [2] Particle #31 - (B) and (E) humic substance/H2O; [3] Particle #71 - (C) and (F)  fly ash

  22. Chemical speciation by low-Z particle EPMA and ATR-FT-IR imaging

  23. Summary and conclusions ■Extensive chemical modification observed for an Asian Dust sample • Among 41 Ca-containing particles, just 2 are calcite and 39 are the reaction products. • First observation of ACC and in-land CaCl2 particles • All 34 NaNO3-containing particles are from chemical reactions between sea-salts and nitrogen oxides. (e.g., NaCl + HNO3 NaNO3 + HCl). • Majority is mixed with organic and minerals. • Among 25 silicates, 10 silicates, including both swelling and non-swelling ones, experienced chemical modifications. • Calcite plays a important role for aging of silicate minerals. • The combined use of low-Z particle EPMA and ATR-FT-IR imaging techniques for the study of complicated chemical modification of Asian Dust particles

  24. “Thank you for your attention !” http://iws.inha.ac.kr/~curo

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