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Titel |
Impact of Mexico City emissions on regional air quality from MOZART-4 simulations |
VerfasserIn |
L. K. Emmons, E. C. Apel, J.-F. Lamarque, P. G. Hess, M. Avery, D. Blake, W. Brune, T. Campos, J. Crawford, P. F. DeCarlo, S. Hall, B. Heikes, J. Holloway, J. L. Jimenez, D. J. Knapp, G. Kok, M. Mena-Carrasco, J. Olson, D. O'Sullivan, G. Sachse, J. Walega, P. Weibring, A. Weinheimer, C. Wiedinmyer |
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 ; 10, no. 13 ; Nr. 10, no. 13 (2010-07-09), S.6195-6212 |
Datensatznummer |
250008611
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Publikation (Nr.) |
copernicus.org/acp-10-6195-2010.pdf |
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Zusammenfassung |
An extensive set of measurements was made in and around Mexico City as
part of the MILAGRO (Megacity Initiative: Local and Global Research
Observations) experiments in March 2006. Simulations with the Model
for Ozone and Related Chemical Tracers, version 4 (MOZART-4), a global
chemical transport model, have been used to provide a regional context
for these observations and assist in their interpretation. These
MOZART-4 simulations reproduce the aircraft observations generally
well, but some differences in the modeled volatile organic compounds
(VOCs) from the observations result from incorrect VOC speciation
assumed for the emission inventories. The different types of
CO sources represented in the model have been "tagged" to
quantify the contributions of regions outside Mexico, as well as the
various emissions sectors within Mexico, to the regional air quality
of Mexico. This analysis indicates open fires have some, but not
a dominant, impact on the atmospheric composition in the region around
Mexico City when averaged over the month. However, considerable
variation in the fire contribution (2–15% of total CO) is seen
during the month. The transport and photochemical aging of Mexico
City emissions were studied using tags of CO emissions for each
day, showing that typically the air downwind of Mexico City was a combination
of many ages. Ozone production in MOZART-4 is shown to agree well
with the net production rates from box model calculations constrained
by the MILAGRO aircraft measurements. Ozone production efficiency
derived from the ratio of Ox to NOz is higher in
MOZART-4 than in the observations for moderately polluted air. OH
reactivity determined from the MOZART-4 results shows the same
increase in relative importance of oxygenated VOCs downwind of Mexico
City as the reactivity inferred from the observations. The amount of
ozone produced by emissions from Mexico City and surrounding areas has
been quantified in the model by tracking NO emissions, showing
little influence beyond Mexico's borders, and also relatively minor
influence from fire emissions on the monthly average tropospheric
ozone column. |
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