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| Titel |
Investigation of aged Asian dust particles by the combined use of quantitative ED-EPMA and ATR-FTIR imaging |
| VerfasserIn |
Y.-C. Song, H.-J. Eom, H.-J. Jung, M. A. Malek, H. K. Kim, H. Geng, C.-U. Ro |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 6 ; Nr. 13, no. 6 (2013-03-27), S.3463-3480 |
| Datensatznummer |
250018543
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| Publikation (Nr.) |
 copernicus.org/acp-13-3463-2013.pdf |
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| Zusammenfassung |
| In our previous works, it was demonstrated that the combined use of
quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA),
which is also known as low-Z particle EPMA, and attenuated total reflectance
Fourier transform infrared spectroscopy (ATR-FTIR) imaging has great potential for a detailed characterization
of individual aerosol particles. In this study, extensively chemically
modified (aged) individual Asian dust particles collected during an Asian
dust storm event on 11 November 2002 in Korea were characterized by the
combined use of low-Z particle EPMA and ATR-FTIR imaging. Overall, 109
individual particles were classified into four particle types based on their
morphology, elemental concentrations, and molecular species and/or
functional groups of individual particles available from the two analytical
techniques: Ca-containing (38%), NaNO3-containing (30%), silicate
(22%), and miscellaneous particles (10%). Among the 41 Ca-containing
particles, 10, 8, and 14 particles contained nitrate, sulfate, and both,
respectively, whereas only two particles contained unreacted CaCO3.
Airborne amorphous calcium carbonate (ACC) particles were observed in this
Asian dust sample for the first time, where their IR peaks for the
insufficient symmetric environment of CO32− ions of ACC were
clearly differentiated from those of crystalline CaCO3. This paper also
reports the first inland field observation of CaCl2 particles
probably converted from CaCO3 through the reaction with HCl(g). HCl(g)
was likely released from the reaction of sea salt with NOx/HNO3,
as all 33 particles of marine origin contained NaNO3 (no genuine sea
salt particle was encountered). Some silicate particles with minor amounts
of calcium were observed to be mixed with nitrate, sulfate, and water. Among
24 silicate particles, 10 particles are mixed with water, the presence of
which could facilitate atmospheric heterogeneous reactions of silicate
particles including swelling minerals, such as montmorillonite and
vermiculite, and nonswelling ones, such as feldspar and quartz. This paper
provides detailed information on the physicochemical characteristics of
these aged individual Asia dust particles through the combined use of the
two single-particle analytical techniques, and using this analytical
methodology it is clearly shown that internal mixing states of the aged
particles are highly complicated. |
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