Smog rating
The EPA's 1 to 10 score for smog-forming tailpipe pollution. Higher is cleaner.
The smog rating scores a vehicle's smog-forming tailpipe pollution, things like nitrogen oxides and particulates, on a 1 to 10 scale from EPA emissions testing. A 10 emits the least; a 1 the most.
It is the local-air-quality counterpart to the eco score: the eco score tracks climate impact (CO2), while the smog rating tracks the pollutants behind urban smog and respiratory problems. Battery EVs score a 10 on both; the cleanest gasoline cars and hybrids also reach the top of the smog scale.