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| Titel |
Long-term measurements of particle number size distributions and the relationships with air mass history and source apportionment in the summer of Beijing |
| VerfasserIn |
Z. B. Wang, M. Hu, Z. J. Wu, D. L. Yue, L. Y. He, X. F. Huang, X. G. Liu, A. Wiedensohler |
| 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. 20 ; Nr. 13, no. 20 (2013-10-16), S.10159-10170 |
| Datensatznummer |
250085754
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| Publikation (Nr.) |
 copernicus.org/acp-13-10159-2013.pdf |
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| Zusammenfassung |
| A series of long-term and temporary measurements were conducted to study the
improvement of air quality in Beijing during the Olympic Games period (8–24 August
2008). To evaluate actions taken to improve the air quality,
comparisons of particle number and volume size distributions of August 2008
and 2004–2007 were performed. The total particle number and volume
concentrations were 14 000 cm−3 and 37 μm−3 cm−3 in August
of 2008, respectively. These were reductions of 41% and 35% compared
with mean values of August 2004–2007. A cluster analysis on air mass
history and source apportionment were performed, exploring reasons for the
reduction of particle concentrations. Back trajectories were classified into
five major clusters. Air masses from the south direction are always associated
with pollution events during the summertime in Beijing. In August 2008, the
frequency of air mass arriving from the south was 1.3 times higher compared
to the average of the previous years, which however did not result in
elevated particle volume concentrations in Beijing. Therefore, the reduced
particle number and volume concentrations during the 2008 Beijing Olympic
Games cannot be only explained by meteorological conditions. Four
factors were found influencing particle concentrations using a positive
matrix factorization (PMF) model. They were identified as local and remote
traffic emissions, combustion sources as well as secondary transformation.
The reductions of the four sources were calculated to 47%, 44%, 43%
and 30%, respectively. The significant reductions of particle number and
volume concentrations may attribute to actions taken, focusing on primary
emissions, especially related to the traffic and combustion sources. |
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