Atmospheric Chemistry and Physics Discussions
www.atmos-chem-phys-discuss.net
1680-7367
1680-7375
6
4
2006
10.5194/acpd-6-6125-2006
http://www.atmos-chem-phys-discuss.net/6/6125/2006/
http://www.atmos-chem-phys-discuss.net/6/6125/2006/acpd-6-6125-2006.html
http://www.atmos-chem-phys-discuss.net/6/6125/2006/acpd-6-6125-2006.pdf
6125
6181
2006-07-11
Modelling constraints on the emission inventory and on vertical diffusion for CO and SO<sub>2</sub> in the Mexico City Metropolitan Area using Solar FTIR and zenith sky UV spectroscopy
B. de Foy
W. Lei
M. Zavala
R. Volkamer
J. Samuelsson
J. Mellqvist
B. Galle
A.-P. MartÃnez
M. Grutter
L. T. Molina
Molina Center for Energy and the Environment, CA, USA
Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, USA
Department of Chemistry and Biochemistry, University of California, San Diego, USA
Department of Radio and Space Science, Chalmers University of Technology, Gothenburg, Sweden
General Direction of the National Center for Environmental Research and Training (CENICA), National Institute of Ecology (INE), Mexico
Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, México
Emissions of air pollutants in and around urban areas lead
to negative health impacts on the population.
To estimate these impacts, it is important to know the
sources and transport mechanisms of the pollutants accurately.
Mexico City has a large urban fleet in a topographically constrained basin
leading to high levels of carbon monoxide (CO). Large point sources
of sulfur dioxide (SO<sub>2</sub>) surrounding the basin lead to episodes with
high concentrations.
An Eulerian grid model (CAMx) and a particle trajectory model
(FLEXPART) are used to evaluate the estimates of CO and SO<sub>2</sub>
in the current emission inventory
using mesoscale meteorological simulations from MM5.
Vertical column measurements of CO are used to constrain the
total amount of emitted CO in the model and to identify the
most appropriate vertical diffusion scheme.
Zenith sky UV spectroscopy is used to estimate the emissions
of SO<sub>2</sub> from a large power plant and the Popocatépetl volcano.
Results suggest that the models are able to identify correctly
large point sources and that both the power plant and the volcano
impact the MCMA.
Modelled concentrations of CO based on the
current emission inventory match observations suggesting that
the current total emissions estimate is correct. Possible adjustments
to the spatial and temporal distribution can be inferred from
model results.
Accurate source and dispersion modelling provides feedback
for development of the emission inventory,
verification of transport processes in air quality models and
guidance for policy decisions.