Single-particle investigation of summertime and wintertime Antarctic sea spray aerosols using low-<i>Z</i> particle EPMA, Raman microspectrometry, and ATR-FTIR imaging techniques
Two aerosol samples collected at King Sejong Korean scientific research station, Antarctica, on 9 December 2011 in the austral summer (sample S1) and 23 July 2012 in the austral winter (sample S2), when the oceanic chlorophyll <i>a</i> levels on the collection days of the samples were...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-11-01
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Series: | Atmospheric Chemistry and Physics |
Online Access: | https://www.atmos-chem-phys.net/16/13823/2016/acp-16-13823-2016.pdf |
Summary: | Two aerosol samples collected at King Sejong Korean scientific research
station, Antarctica, on 9 December 2011 in the austral summer (sample S1) and
23 July 2012 in the austral winter (sample S2), when the oceanic
chlorophyll <i>a</i> levels on the collection days of the samples were quite
different, by ∼ 19 times (2.46 vs. 0.13 µg L<sup>−1</sup>,
respectively), were investigated on a single-particle basis using
quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA),
called low-<i>Z</i> particle EPMA, Raman microspectrometry (RMS), and
attenuated total reflection Fourier transform infrared (ATR-FTIR) imaging
techniques to obtain their characteristics based on the elemental chemical
compositions, molecular species, and mixing state. X-ray analysis showed that
the supermicron summertime and wintertime Antarctic aerosol samples have
different elemental chemical compositions, even though all the individual
particles analyzed were sea spray aerosols (SSAs); i.e., the contents of C,
O, Ca, S, and Si were more elevated, whereas Cl was more depleted, for
sample S1 than for sample S2. Based on qualitative analysis of the chemical
species present in individual SSAs by the combined application of RMS and
ATR-FTIR imaging, different organic species were observed in samples S1 and
S2; i.e., Mg hydrate salts of alanine were predominant in samples S1 and S2,
whereas Mg salts of fatty acids internally mixed with Mg hydrate salts of
alanine were significant in sample S2. Although CaSO<sub>4</sub> was observed
significantly in both samples S1 and S2, other inorganic species, such as
Na<sub>2</sub>SO<sub>4</sub>, NaNO<sub>3</sub>, Mg(NO<sub>3</sub>)<sub>2</sub>, SiO<sub>2</sub>, and
CH<sub>3</sub>SO<sub>3</sub>Mg, were observed more significantly in sample S1, suggesting
that those compounds may be related to the higher phytoplankton activity in
summer. |
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ISSN: | 1680-7316 1680-7324 |