When Carol Browner, head of the Environmental Protection Agency, proposed new air quality standards last year, she claimed that thousands of Americans are being killed every year by tiny particles in the air with diameters of less than 2.5 microns. The EPA currently regulates airborne pollutants 10 microns in diameter, so Browner asked to have the agency's powers expanded. Charcoal grills, lawnmowers, and other gasoline-powered equipment could be outlawed when they produce too much pollution.