Presentation by Professor John Spengler Professor John Spengler noted that Mexicans have long-term monitoring data, and a sense of the trends and spatial distributions of pollution, which is more than the case for many cities. Ozone in Mexico City is the highest he has seen in the world, he said, while particulates, though also a problem, are not as severe as in Beijing or Delhi. He pointed out that Mexico experiences forest fires and warm dry spells where wind speeds drop by a factor of two for a whole year. These environmental and meteorological events need to be incorporated into de-trending the data. With respect to monitoring, he asked whether the right compounds are being measured.
Instrumentation also plays a crucial role in the validity of the data.
He asked if the right instruments were being used, and used correctly. In the case of PM, for example, we don't even know what component of particles we should be measuring. All measurements are approximations, he pointed out, and researchers should look for consistencies in the dose-response relationship. Perhaps there is a need to institutionalize these studies and expand what's monitored, he suggested. Discussing population exposures, Prof. Spengler explained why exposure data are needed even if there is so much ambient monitoring.