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| Titel |
VOC reactivity and its effect on ozone production during the HaChi summer campaign |
| VerfasserIn |
L. Ran, C. S. Zhao, W. Y. Xu, X. Q. Lu, M. Han, W. L. Lin, P. Yan, X. B. Xu, Z. Z. Deng, N. Ma, P. F. Liu, J. Yu, W. D. Liang, L. L. Chen |
| 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 ; 11, no. 10 ; Nr. 11, no. 10 (2011-05-18), S.4657-4667 |
| Datensatznummer |
250009745
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| Publikation (Nr.) |
 copernicus.org/acp-11-4657-2011.pdf |
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| Zusammenfassung |
| Measurements of ozone and its precursors conducted within the HaChi (Haze in
China) project in summer 2009 were analyzed to characterize volatile organic
compounds (VOCs) and their effects on ozone photochemical production at a
suburban site in the North China Plain (NCP). Ozone episodes, during which running
8-h average ozone concentrations exceeding 80 ppbv lasted for more than 4
h, occurred on about two thirds of the observational days during the
5-week field campaign. This suggests continuous ozone exposure risks in this
region in the summer. Average concentrations of nitrogen oxides (NOx) and
VOCs are about 20 ppbv and 650 ppbC, respectively. On average, total VOC
reactivity is dominated by anthropogenic VOCs. The contribution of biogenic
VOCs to total ozone-forming potential, however, is also considerable in the
daytime. Key species associated with ozone photochemical production are
2-butenes (18 %), isoprene (15 %), trimethylbenzenes (11 %), xylenes
(8.5 %), 3-methylhexane (6 %), n-hexane (5 %) and toluene (4.5 %).
Formation of ozone is found to be NOx-limited as indicated by measured
VOCs/NOx ratios and further confirmed by a sensitivity study using a
photochemical box model NCAR_MM. The Model simulation suggests that ozone
production is also sensitive to changes in VOC reactivity under the
NOx-limited regime, although this sensitivity depends strongly on how much
NOx is present. |
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