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| Titel |
Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City |
| VerfasserIn |
E. Velasco, C. Márquez, E. Bueno, R. M. Bernabé, A. Sanchez, O. Fentanes, H. Wöhrnschimmel, B. Cárdenas, A. Kamilla, S. Wakamatsu, L. T. Molina |
| 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 ; 8, no. 12 ; Nr. 8, no. 12 (2008-06-20), S.3061-3079 |
| Datensatznummer |
250006217
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| Publikation (Nr.) |
 copernicus.org/acp-8-3061-2008.pdf |
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| Zusammenfassung |
| The evolution of ozone (O3) and 13 volatile organic compounds (VOCs) in
the boundary layer of Mexico City was investigated during 2000–2004 to
improve our understanding of the complex interactions between those trace
gases and meteorological variables, and their influence on the air quality
of a polluted megacity. A tethered balloon, fitted with electrochemical and
meteorological sondes, was used to obtain detailed vertical profiles of
O3 and meteorological parameters up to 1000 m above ground during part
of the diurnal cycle (02:00–18:00 h). VOCs samples were collected up to 200 m
by pumping air to canisters with a Teflon tube attached to the tether
line. Overall, features of these profiles were found to be consistent with
the formation of an upper residual layer during nighttime carrying over a
fraction of the O3 from the previous day that contributes to the
background concentration in surrounding regions. At the same time the
release of heat stored in the urban surface forms a shallow unstable layer
close to the ground, where the nocturnal emissions are trapped. After
sunrise an O3 balance is determined by photochemical production,
entrainment from the upper residual layer and destruction by titration with
nitric oxide, delaying the ground-level O3 rise by 2 h. The
subsequent evolution of the conductive boundary layer and vertical
distribution of pollutants are discussed in terms of the energy balance, the
presence of turbulence and the atmospheric stability. |
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