The federal government wants cleaner gasoline to help reduce smog.
That's according to the head of a group of clean air agencies, who adds the Environmental Protection Agency will announce the new rules on Friday.
Bill Becker, who heads up the National Association of Clean Air Agencies, says reducing the sulfur in gasoline is one of the most effective ways to clean up the air.
Becker estimates the new sulfur rule will cut smog by about 30 percent.
Critics of the new rule say it will raise the price of a gallon of gas by about a dime.