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| Titel |
Mixing state and sources of submicron regional background aerosols in the northern Qinghai–Tibet Plateau and the influence of biomass burning |
| VerfasserIn |
W. J. Li, S. R. Chen, Y. S. Xu, X. C. Guo, Y. L. Sun, X. Y. Yang, Z. F. Wang, X. D. Zhao, J. M. Chen, 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. 23 ; Nr. 15, no. 23 (2015-12-02), S.13365-13376 |
| Datensatznummer |
250120200
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| Publikation (Nr.) |
 copernicus.org/acp-15-13365-2015.pdf |
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| Zusammenfassung |
| Transmission electron microscopy (TEM) was employed to obtain
morphology, size, composition, and mixing state of background aerosols with
diameter less than 1 μm in the northern Qinghai–Tibet Plateau (QTP)
during 15 September to 15 October 2013. Individual aerosol particles mainly
contained secondary inorganic aerosols (SIA – sulfate and nitrate) and
organics during clean periods (PM2.5 mass concentration less than 2.5 μg m−3). The presence of K–Na–Cl associated with organics and an
increase in soot particles suggest that an intense biomass burning event
caused the highest PM2.5 concentrations (> 30 μg m−3) during the study. A large number fraction of the
fly-ash-containing particles (21.73 %) suggests that coal combustion emissions
in the QTP significantly contributed to air pollutants at the medium
pollution level (PM2.5: 10–30 μg m−3). We concluded
that emissions from biomass burning and from coal combustion both constantly
contribute to anthropogenic particles in the QTP atmosphere. Based on size
distributions of individual particles at different pollution levels, we
found that gas condensation on existing particles is an important chemical
process for the formation of SIA with organic coating. TEM observations show
that refractory aerosols (e.g., soot, fly ash, and visible organic
particles) likely adhere to the surface of SIA particles larger than 200 nm
due to coagulation. Organic coating and soot on surface of the aged
particles likely influence their hygroscopic and optical properties, respectively, in the
QTP. To our knowledge, this study reports the first
microscopic analysis of fine particles in the background QTP air. |
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