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

[摘要] Emissions of air pollutants in and around urban areas leadto negative health impacts on the population.To estimate these impacts, it is important to know thesources and transport mechanisms of the pollutants accurately.Mexico City has a large urban fleet in a topographically constrained basinleading to high levels of carbon monoxide (CO). Large point sourcesof sulfur dioxide (SO₂) surrounding the basin lead to episodes withhigh concentrations.An Eulerian grid model (CAMx) and a particle trajectory model(FLEXPART) are used to evaluate the estimates of CO and SO₂in the current emission inventoryusing mesoscale meteorological simulations from MM5.Vertical column measurements of CO are used to constrain thetotal amount of emitted CO in the model and to identify themost appropriate vertical dispersion scheme.Zenith sky UV spectroscopy is used to estimate the emissionsof SO₂ from a large power plant and the Popocatépetl volcano.Results suggest that the models are able to identify correctlylarge point sources and that both the power plant and the volcanoimpact the MCMA.Modelled concentrations of CO based on thecurrent emission inventory match observations suggesting thatthe current total emissions estimate is correct. Possible adjustmentsto the spatial and temporal distribution can be inferred frommodel results.Accurate source and dispersion modelling provides feedbackfor development of the emission inventory,verification of transport processes in air quality models andguidance for policy decisions.

[学科分类] 大气科学