Our Small World

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What’s the dirt on dust storms?

Dust. You may think of it as something that collects around the house and requires a lot of tedious cleaning. And it is. Did you know, though, that dust is also a key example of transboundary pollution and a health hazard? Each year, three billion tons of dust swirl across the face of the planet.

A dust storm blankets the Persian Gulf.
Source: NASA

The number of dust storms is rising, moreover. Sub-Saharan Africa, for example, now has ten times as many dust storms as it did 50 years ago. The reasons for that change include deforestation, overgrazing, and the shrinking of Lake Chad. A single one of those African storms may be 200 kilometers (124 miles) wide and carry 100 tons of dust. Given strong enough winds, the dust can travel all the way to North America. It can also land in the ocean, where it harms coral reefs.

Globetrotting dust is bad enough, but dust storms can carry other things that make people sick. These include poisons from pesticides or herbicides, microbes that can cause illness, and salt from lakes or seas, such as the Aral Sea, that are drying up. These particles find their way into people’s lungs and lead to respiratory troubles. Dust problems can be local, too. Each year, for instance, several Americans die from San Joaquin Valley fever, a fungal infection named after the California valley where the first cases of illness were found. Bulldozers had sent contaminated dust airborne. (About 3 percent of people living in an area with this fungus get the disease. Symptoms may not develop until more than 20 years after the initial infection.)

Meet a Texas student who learned what the wind was carrying her way.