[WardL]

The EPA has forced the reduction in sulfur in gasoline too. It used to be limited to 1,000 ppm, but starting in about 2006 (?) the max is 80 ppm and the average is less than 30 ppm sulfur in gasoline. The benefit of lower sulfur is not to reduce the sulfur dioxide in the air, it is to help the catalytic converters to last longer. It is a good thing.