It's not easy, but Institute Professor Mario Molina is doing his best to help his hometown clean up its air.
Mexico City's location in a pollutant-trapping valley -- and its more than 3.5 million vehicles and 35,000 industries, which produce thousands of tons of emissions each year -- have made the Mexico City Metropolitan Area (MCMA) one of the most polluted regions on the planet. The sky over this home to 18 million is often brown.
Professor Molina, who won the 1995 Nobel Prize in chemistry for discovering that the ozone layer was being depleted by chlorofluorocarbon gases, last month presented the final report on "Project for the Design of an Integrated Strategy for the Management of Air Pollution in the Mexico City Metropolitan Area 2001-2010" to Mexican federal and state officials, industry representatives and academicians.
Professor Molina and his wife, Luisa, a research scientist in the Department of Earth, Atmospheric and Planetary Sciences, have been working on this long-term project with an interdisciplinary and multidisciplinary group of Mexican researchers, including scientists, economists, sociologists and policy makers, as well as MIT and Harvard students, professors and researchers.
Solving Mexico City's air pollution problem "is not a luxury, but a necessity," he wrote. "Some of the necessary measures may seem costly and bothersome. However, any delay in tackling the air pollution problem may create the need for more drastic measures in the future."
The study makes recommendations related to regulations and air pollution control in Mexico City and to research and assessment exercises.
Among other things, the study recommends developing and evaluating control strategies based on a cost-benefit analysis, with particular emphasis on ways to reduce the exposure of the population to fine particles and ozone; determining whether fine particles are more toxic than coarse particles; and exploring whether exposure to air pollution causes increases in infant mortality.
The study points out that the use of private automobiles and low-occupancy mass-transit vehicles is on the rise because the existing transportation system has not adapted to the changing population distribution, economic changes and resulting new traffic patterns. Although the local government has taken major steps to reduce transportation emissions, serious problems remain.
In addition, the study notes that educational and outreach activities aimed at the general public should be continued.
The Mexico City project is a case study that may be applied to other areas in the future.
Professor Molina was born in Mexico City in 1943. He came to MIT in 1989.
A version of this article appeared in MIT Tech Talk on December 6, 2000.