On the usefulness of atmospheric measurements for air quality evaluation in the context of recent urban meteorology findings in Mexico City

摘要

In many cities, the main tool used to assess pollution abatement policies is the air quality information obtained from local monitoring network. However, in the context of a complex meteorology and land use such as those prevailing in Mexico City, the point-wise character and lack of detailed chemistry of this information may confer conflictive or biased information. The approach to understand the problem could be not based on solid ground. It is not until the measurement effort is complemented with detailed meteorological and air quality modeling that proper use of the information can be assured. In order to provide an example of this assertion, the usefulness of measured air quality data is gauged in a simplified manner, constructing three dimensional graphs containing local emission concentrations of nitrogen oxides (NO.), volatile organic compounds (VOC) and maximum ozone (O-3) concentrations, that we call "ozone isopleths", for three sites in Mexico City. Together with corresponding wind rose data, an interpretation of the air pollution transport in the Valley of Mexico using only measured data is attempted. This interpretation, based on measured information subject to local influences, is compared with recent air quality modeling results showing that when measured data is used in conjunction with air quality modeling a better interpretation of air pollution problem can be obtained. A correct strategy to study the air quality problem, especially in the case of Mexico City where complex meteorology and land use is present, should be that both endeavors, measuring and modeling, are pursued with equal vigor.