Today's date:
Winter 2005

Pollution Solution Is Global

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

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 which 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, the only solution is global.

Anything we put into the atmosphere that lasts for a week will make it between continents. It takes five to seven days for the atmospheric currents to carry dust, smoke or industrial pollutants from Asia to the US. This is of particular concern because of the infamous "Asian brown cloud" that has resulted from rapid industrial growth in India and China. At lower latitudes, a dust storm in 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 health through increased mortality and breathing problems, but because they also have an impact on climate change.

On the one hand, haze which contains sulfuric acid from burning coal, for example, can mitigate the greenhouse effect by reflecting back some solar radiation. This can actually contribute to cooling. On the other hand, dark particles which enter the atmosphere from diesel engine exhaust, forest fires or slash-and-burn agriculture 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-burn agriculture, widely used throughout the developing countries, has to be harshly curbed. 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 those solutions are global and work in concert, we can clean up the planet. This is one set of problems we can fix.