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| Titel |
Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the Arctic troposphere |
| VerfasserIn |
J. W. Chi, W. J. Li, D. Z. Zhang, J. C. Zhang, Y. T. Lin, X. J. Shen, J. Y. Sun, J. M. Chen, X. Y. Zhang, Y. M. Zhang, W. X. Wang |
| 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 ; 15, no. 19 ; Nr. 15, no. 19 (2015-10-12), S.11341-11353 |
| Datensatznummer |
250120093
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| Publikation (Nr.) |
 copernicus.org/acp-15-11341-2015.pdf |
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| Zusammenfassung |
| Sea salt aerosols (SSA) are dominant particles in the Arctic atmosphere and
determine the polar radiative balance. SSA react with acidic pollutants that
lead to changes in physical and chemical properties of their surface, which
in turn alter their hygroscopic and optical properties. Transmission electron
microscopy with energy-dispersive X-ray spectrometry was used to analyze
morphology, composition, size, and mixing state of individual SSA at
Ny-Ålesund, Svalbard, in summertime. Individual fresh SSA contained cubic
NaCl coated by certain amounts of MgCl2 and CaSO4. Individual
partially aged SSA contained irregular NaCl coated by a mixture of
NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The
comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely
intrigued the heterogeneous reactions at the beginning of SSA and acidic
gases. Individual fully aged SSA normally had Na2SO4 cores and an
amorphous coating of NaNO3. Elemental mappings of individual SSA
particles revealed that as the particles ageing Cl gradually decreased, the
C, N, O, and S content increased. 12C- mapping from nanoscale
secondary ion mass spectrometry indicates that organic matter increased in
the aged SSA compared with the fresh SSA. 12C- line scan further
shows that organic matter was mainly concentrated on the aged SSA surface.
These new findings indicate that this mixture of organic matter and
NaNO3 on particle surfaces likely determines their hygroscopic and
optical properties. These abundant SSA as reactive surfaces adsorbing
inorganic and organic acidic gases can shorten acidic gas lifetime and
influence the possible gaseous reactions in the Arctic atmosphere, which need
to be incorporated into atmospheric chemical models in the Arctic
troposphere. |
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