The combination of particle traps and low-sulfur fuel can reduce soot by well over 90 percent, and make deep cuts in other pollutants.

Now we have trucks on the road that are reducing soot by 90 percent and are going 50 percent farther on a gallon of fuel.

The 1KZ-TE was able to reduce NOx and soot.

Denver's return to clean-air status has come largely through efforts to reduce ozone, carbon monoxide and soot.

The city and the nation have made great strides since 1970 in reducing airborne soot, lead and sulfur dioxide.

The air quality gain would be substantial, reducing both soot in the air and sulfur dioxide emissions.

The dispute continued at hearings here by the Environmental Protection Agency on a proposal to toughen regulations designed to reduce smog and soot.

The new vehicles cut smog-forming pollution by 65%, reduce soot by 96%, and move 57% farther on a gallon of fuel.

May 1952: Fitted with Thornycroft funnel to reduce soot.

And reducing airborne soot will take even longer, until 2015 at the earliest.