Although Mexico City has the dubious distinction of having the worst air quality in the world, its problems with pollution are not unique. Researchers at Washington State University’s Laboratory of Atmospheric Research are working with a group of more than 20 universities and government agencies who are using Mexico City as a case study in how to tackle the huge problem of air quality in megacities.
Led by Mario Molina of the Massachusetts Institute of Technology, the researchers hope to gather information from a large number of groups and eventually help to devise better emissions-control strategies for the region. Using a variety of technologies and a number of agencies to gather information assures better confidence in the results, says Brian Lamb, professor in civil engineering who led the WSU group. The information could also be used to better understand and improve air pollution problems in other major urban areas.
Lamb’s group studied the emissions of organic hydrocarbons from the urban landscape. Hydrocarbons are released into the atmosphere from incomplete combustion of gasoline and other fuels and from other sources such as dry cleaners, paint shops, and solvent use. In the atmosphere, hydrocarbons react with sunlight and nitrogen oxides to produce ozone and smog. In Mexico City the standard for ozone is exceeded 300 days per year.
While Lamb’s group found that cars are a big source of hydrocarbon emissions, they also found that the many small cottage industries, ranging from repair shops to a factory that cleans eggs, are also significant contributors to pollution. Even painting sidewalk curbs produced significant organic molecules.
“With a population of 20 million people and horrendous traffic, they have a long way to go,” says Lamb.