10. Infiniti G37 Coupe (w/ manual trans.)

Air Pollution Score: 7
(higher is better)

Carbon Footprint:
9.2 annual tons
(annual tons of greenhouse-gas emissions; lower is better)

The sleek Infiniti G37 Coupe sneaks onto our list as one of the most eco-friendly luxury rides thanks to a clean-running 3.7-liter V6 engine connected to a six-speed manual transmission. This duo drives the rear wheels and allows the G37 Coupe to get 17 mpg city/26 mpg highway. That's the poorest fuel economy of this group and results in the largest carbon footprint.