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Titel |
Asian dust storm observed at a rural mountain site in southern China: chemical evolution and heterogeneous photochemistry |
VerfasserIn |
W. Nie, T. Wang, L. K. Xue, A. J. Ding, X. F. Wang, X. M. Gao, Z. Xu, Y. C. Yu, C. Yuan, Z. S. Zhou, R. Gao, X. H. Liu, Y. Wang, S. J. Fan, S. Poon, Q. Z. 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 ; 12, no. 24 ; Nr. 12, no. 24 (2012-12-17), S.11985-11995 |
Datensatznummer |
250011675
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Publikation (Nr.) |
copernicus.org/acp-12-11985-2012.pdf |
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Zusammenfassung |
Heterogeneous processes on dust particles are important for understanding
the chemistry and radiative balance of the atmosphere. This paper
investigates an intense Asian dust storm episode observed at Mount Heng
(1269 m a.s.l.) in southern China on 24–26 April 2009. A set of aerosol and
trace gas data collected during the study was analyzed to investigate their
chemical evolution and heterogeneous photochemistry as the dust traveled to
southern China. Results show that the mineral dust arriving at Mt. Heng
experienced significant modifications during transport, with large
enrichments in secondary species (sulfate, nitrate, and ammonium) compared
with the dust composition collected at an upwind mountain top site (Mount
Hua). A photochemical age "clock" (−Log10(NOx/NOy)) was
employed to quantify the atmospheric processing time. The result indicates
an obvious increase in the abundance of secondary water-soluble ions in dust
particles with the air mass atmospheric processing time. Based on the
observations, a 4-stage evolution process is proposed for
carbonate-containing Asian dust, starting from fresh dust to particles
coated with hydrophilic and acidic materials. Daytime-enhanced nitrite
formation on the dust particles was also observed, which indicates the
recent laboratory result of the TiO2 photocatalysis of NO2 as a
potential source of nitrite and nitrous acid. |
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