Modelling constraints on the emission inventory and on vertical dispersion for CO and SO2 in the Mexico City Metropolitan Area using Solar FTIR and zenith sky UV spectroscopy B. de Foy1,*, W. Lei2, M. Zavala2, R. Volkamer3, J. Samuelsson4, J. Mellqvist4, B. Galle4, A.-P. Martínez5, M. Grutter6, A. Retama7, and L. T. Molina1,2 1Molina Center for Energy and the Environment, La Jolla, USA 2Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, USA 3Department of Chemistry and Biochemistry, University of California, San Diego, USA 4Department of Radio and Space Science, Chalmers University of Technology, Gothenburg, Sweden 5General Direction of the National Center for Environmental Research and Training (CENICA), National Institute of Ecology (INE), Mexico 6Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico 7Secretaría del Medio Ambiente, Gobierno del Distrito Federal, Mexico *now at: Saint Louis University, USA
Abstract. 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 (SO2) surrounding the basin lead to episodes with
An Eulerian grid model (CAMx) and a particle trajectory model
(FLEXPART) are used to evaluate the estimates of CO and SO2
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 dispersion scheme.
Zenith sky UV spectroscopy is used to estimate the emissions
of SO2 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
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.
Citation: de Foy, B., Lei, W., Zavala, M., Volkamer, R., Samuelsson, J., Mellqvist, J., Galle, B., Martínez, A.-P., Grutter, M., Retama, A., and Molina, L. T.: Modelling constraints on the emission inventory and on vertical dispersion for CO and SO2 in the Mexico City Metropolitan Area using Solar FTIR and zenith sky UV spectroscopy, Atmos. Chem. Phys., 7, 781-801, doi:10.5194/acp-7-781-2007, 2007.