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Titel |
Process analysis of regional ozone formation over the Yangtze River Delta, China using the Community Multi-scale Air Quality modeling system |
VerfasserIn |
L. Li, C. H. Chen, C. Huang, H. Y. Huang, G. F. Zhang, Y. J. Wang, H. L. Wang, S. R. Lou, L. P. Qiao, M. Zhou, M. H. Chen, Y. R. Chen, D. G. Streets, J. S. Fu, C. J. Jang |
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. 22 ; Nr. 12, no. 22 (2012-11-21), S.10971-10987 |
Datensatznummer |
250011610
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Publikation (Nr.) |
copernicus.org/acp-12-10971-2012.pdf |
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Zusammenfassung |
A high O3 episode was detected in urban Shanghai, a typical city in the
Yangtze River Delta (YRD) region in August 2010. The CMAQ integrated process
rate method is applied to account for the contribution of different
atmospheric processes during the high pollution episode. The analysis shows
that the maximum concentration of ozone occurs due to transport phenomena,
including vertical diffusion and horizontal advective transport. Gas-phase
chemistry producing O3 mainly occurs at the height of 300–1500 m,
causing a strong vertical O3 transport from upper levels to the surface
layer. The gas-phase chemistry is an important sink for O3 in the
surface layer, coupled with dry deposition. Cloud processes may contribute
slightly to the increase of O3 due to convective clouds or to the
decrease of O3 due to scavenging. The horizontal diffusion and
heterogeneous chemistry contributions are negligible during the whole
episode. Modeling results show that the O3 pollution characteristics
among the different cities in the YRD region have both similarities and
differences. During the buildup period, the O3 starts to appear in the
city regions of the YRD and is then transported to the surrounding areas
under the prevailing wind conditions. The O3 production from
photochemical reaction in Shanghai and the surrounding area is most
significant, due to the high emission intensity in the large city; this
ozone is then transported out to sea by the westerly wind flow, and later
diffuses to rural areas like Chongming island, Wuxi and even to Nanjing. The
O3 concentrations start to decrease in the cities after sunset, due to
titration of the NO emissions, but ozone can still be transported and
maintain a significant concentration in rural areas and even regions outside
the YRD region, where the NO emissions are very small. |
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