[Ben Ficklin]

Burning gasoline or diesel in an ICE creates NOx, which reacts with VOCs to produce Ozone. If you live in an attainment area, you have to have your tailpipe tested to make sure your auto emission controls are working.

Ozone is a very contentious issue right now because Obama/EPA may lower the level of ozone in the air below the 75 ppm that Bush set.

Also, burning fuel releases Sulfur and the refineries remove sulfur from gasoline. Sometime this year, the Tier 3 gasoline with even lower sulfur content is supposed to be coming on line, which will make gasoline cost more.

But we should not worry because in the coming years auto CAFE standards will be rising, which will lower tailpipe emissions of the traditional pollutants as well as CO2.

[__rvx86]

Burning gasoline is somewhat of a balancing act...burning lean will evolve NO_x, SO_x and O₃ species....burning rich will fail to consume the full hydrocarbon charge, resulting in soot/HC emissions...

Isn't there a wet-process catalyst, similar to the type used in newer distillate-burning engines, that could reduce emissions in gasoline engines?