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Mario Molina, professor of chemistry at MIT and the Scripps Institution of Oceanography in San Diego, was awarded the Nobel Prize in 1995 for his work on atmospheric chemistry and stratospheric ozone depletion.

By Mario Molina

MEXICO CITY — Last summer, the NASA satellites Terra and Aqua traced the smoke from an Alaskan spruce fire as it drifted down over southern Florida and the Caribbean and then out around the globe.

The industrial "plume" from the Northeast United States has long been known to end up fouling the air in Western Europe.

Pollution from northern India ends up falling in China as acid rain.

It is estimated that a third of the smog-forming ozone in California by 2010 will originate in booming Asia. No matter how stringent California's environmental regulations may be, the smog that smothers Los Angeles can't be eliminated without the cooperation of China.

This is the new reality in the 21st century: Because pollution crosses borders, only a global approach can solve the problem.

Anything we put into the atmosphere that lasts for a week will make it between continents. It takesfive to seven days for the atmospheric currents to carry dust, smoke or industrial pollutants from Asia to the United States. This is of particular concern because of the infamous "Asian brown cloud" that has resulted from rapid industrial growth in India and China. A dust storm in the lower latitudes of the Sahara Desert can end up as background pollution in Florida.

Atmospheric brown clouds, originating in Asia or elsewhere, are a concern not only because bad air quality affects breathing and causes increased mortality rates, but also because they have an impact on climate change.

On theone hand, haze thatcontains sulfuric acid from burning coal, for example, can mitigate the greenhouseeffect by reflecting back some solar radiation. This can actually contribute to cooling.

On theother hand, dark particles thatenter the atmosphere from diesel engine exhaust, forest fires or slash-and-burnagriculture can result in the "burning cloud" effect: Dark particles absorb solar radiation and cause clouds to evaporate, intensifying heat and thus increasing temperatures. Particularly in the Northern Hemisphere, the combination of these effects is changing the way the atmosphere functions.

Unlike greenhouse gases such as CO2 that warm the atmosphere, air pollutants are short-lasting. Intelligent public policies can diminish their threat to both health and climate change almost immediately.

First, power plants, particularly now in China, need to be cleaned up by using scrubbers and stopping the use of dirty coal. Once power plants are cleaned up, the next greatest culprit is the transportation sector. Catalytic converters have been in use for decades now from Los Angeles to Mexico City. They are a global necessity in our burgeoning megacities. Hybrid car technology is now becoming widely available. These cars are not only fuel-efficient but also emit less CO2.

Finally, slash-and-burnagriculture, widely used throughout the developing countries, has to be dramaticallycurbed. One of the most promising avenues of change here is using biomass waste to produce ethanol, which can be used as a clean-burning fuel for the transport sector. That kills two birds with one stone.

In short, there are solutions to pollution. If we recognize that these solutions must beimplemented in all corners of the globe and work in concert, we can clean up the planet. This is a problemwe can fix.

(c) Nobel Laureates Plus
Distributed by Tribune Media Service, INC. (11/16/04)