In actual fact SUV's emit more pollution of all types, not just CO2 per "gallon" of fuel burned than just about any other car you care to name, this is mostly due in part to the engine designs being the engine equivalent of modern dinosaurs.

I think CO2 is a bit of a red herring here. Any two engines will produce (essentially) the same amount of CO2 from one gallon of the same fuel. CO2 is a product of clean burning of hydrocarbons, along with water vapour, and despite being a greenhouse gas it is naturally present in the atmosphere and so probably isn't a "pollutant" in the sense meant by the study quoted in number6's post. At least in this country, when people talk about pollutants from vehicle emissions, they mean CO, nitrous oxides, and all the stuff (e.g. from fuel additives) that isn't CO2 or water vapour.

Peter