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| Titel |
Ground-level ozone in four Chinese cities: precursors, regional transport and heterogeneous processes |
| VerfasserIn |
L. K. Xue, T. Wang, J. Gao, A. J. Ding, X. H. Zhou, D. R. Blake, X. F. Wang, S. M. Saunders, S. J. Fan, H. C. Zuo, 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 ; 14, no. 23 ; Nr. 14, no. 23 (2014-12-10), S.13175-13188 |
| Datensatznummer |
250119231
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| Publikation (Nr.) |
 copernicus.org/acp-14-13175-2014.pdf |
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| Zusammenfassung |
| We analyzed the measurements of ozone (O3) and its precursors made at
rural/suburban sites downwind of four large Chinese cities – Beijing,
Shanghai, Guangzhou and Lanzhou, to elucidate their pollution
characteristics, regional transport, in situ production, and impacts of
heterogeneous processes. The same measurement techniques and
observation-based model were used to minimize uncertainties in comparison of
the results due to difference in methodologies. All four cities suffered
from serious O3 pollution but showed different precursor distributions.
The model-calculated in situ O3 production rates were compared with the
observed change rates to infer the relative contributions of on-site
photochemistry and transport. At the rural site downwind of Beijing, export
of the well-processed urban plumes contributed to the extremely high O3
levels (up to an hourly value of 286 ppbv), while the O3 pollution
observed at suburban sites of Shanghai, Guangzhou and Lanzhou was dominated
by intense in situ production. The O3 production was in a volatile organic compound (VOC)-limited regime
in both Shanghai and Guangzhou, and a NOx-limited regime in Lanzhou.
The key VOC precursors are aromatics and alkenes in Shanghai, and aromatics
in Guangzhou. The potential impacts on O3 production of several
heterogeneous processes, namely, hydrolysis of dinitrogen pentoxide
(N2O5), uptake of hydro peroxy radical (HO2) on particles and
surface reactions of NO2 forming nitrous acid (HONO), were assessed.
The analyses indicate the varying and considerable impacts of these
processes in different areas of China depending on the atmospheric
abundances of aerosol and NOx, and suggest the urgent need to better
understand these processes and represent them in photochemical models. |
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