11.   The review concludes there is a stronger link than ever between the tiniest soot particles and thousands of premature deaths each year.

12.   The same ruling overturned new standards for soot particles.

13.   The switch is important not only because the new fuel reduces the amount of soot particles and airborne sulfur, a component of ozone and smog.

14.   They point to research indicating that tiny soot particles can cause cancer, and warn that diesels will always create more soot than gasoline engines.

15.   Under administrator Carol Browner, the EPA pushed for tougher air quality standards, lowering the allowable limits for ozone and small soot particles.

16.   Under EPA administrator Carol Browner, the EPA pushed for tougher air quality standards, lowering the allowable limits for ozone and small soot particles.

17.   Soot particles can be generated by industry, power plants and vehicle exhaust.

18.   Soot particles that are suspended overnight in the atmosphere are coated with nitrogen dioxide.