Pollution from around the globe taints U.S. air and water

Even as battles rage in Washington, D.C., over controlling air pollution from domestic sources, dirty emissions from overseas are complicating the problem. Some 30 percent of the ozone in the U.S. may be drifting in from other countries, says NOAA scientist David Parrish. Dust from as far abroad as the Sahara Desert regularly travels across the Atlantic, increasing particulate levels in some U.S. cities. More worrisome is globe-trotting airborne mercury, chiefly from power plants and factories. It drifts around the world, settling in water bodies where it’s absorbed by fish and then passed on up the food chain. Though the U.S. EPA estimates about 40 percent of mercury in the U.S. originates elsewhere, the U.S. last year opposed an international treaty that would have set mandatory mercury limits. Of course, the U.S. does its share of pollution exporting as well. It’s a small world after all, and we’re all (cough) neighbors now.