Local wind and air pollution interaction in the Mexico basin



Components of the thermotopographic wind regime in the Mexico City basin are examined in their interaction with the heat island induced centripetal circulation. The resulting wind regime is such that convergent surface flow over the city is predominant mainly during the night and early morning. The low-level convergence of air flow into the city, although weakened by turbulence and up-slope valley winds is still evident on daytime mean maps of resultant winds from a network of 9 stations. The position of the maximum SO2 isolines is almost coincident with the corresponding position of the heat island. It is concluded that, for the period examined, the local thermally generated winds in Mexico City tend to restrict the ventilation of the polluted air near the surface.

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