The Dustup Over Dust

Many Americans believe the air they breathe is getting cleaner. But in recent years, scientists have pieced together evidence showing that a largely unregulated class of pollutants--tiny dust particles known as fine particulates--may be causing thousands of deaths each year. These microscopic specks appear to lodge deep in the lungs, where they may cause long-term damage. "This research burst on the scene like a bombshell," says James N. Pitts Jr., a chemist and chairman of California's Scientific Review Panel for Toxic Air Contaminants.

Now comes the policy bombshell. On Nov. 29, the Environmental Protection Agency will propose the first health-based standard to control these fine particulates. Under pressure from an American Lung Assn. lawsuit, the agency is expected to set a standard regulating dust 2.5 microns in diameter or smaller. These particles have not previously been regulated. The regulations aren't expected to take effect until at least 2004.