A Clean-Air Car Primer

Note:  to compare vehicles by fuel economy, fuel types, and emissions, see California Air Resources Board Drive Clean California and the EPA Green Vehicle Guide.

ZEVs are zero-emission vehicles, the cleanest you can find. The only ZEVs are electric vehicles, and some fuel cell vehicles (not available to consumers for several years). It’s difficult for a consumer to purchase a new electric vehicle at this point, as there are not many on the market.

PZEVs are partial zero-emission vehicles, the closest you can get to zero without being a ZEV. The partial refers to the fact that automakers get partial ZEV credit for making and selling PZEVs. They’re cleaner than SULEVs since they also have a design that doesn’t allow evaporative emissions from the gas tank. There are PZEV versions of several new gasoline car models on the market today. To see a list of these, visit the California Air Resources Board link in the list below.

AT PZEVs are PZEVs that have an advanced-technology component, such as a hybrid system.

SULEVs are super-ultra low-emission vehicles, extremely clean.  There are both gas SULEVs and gas-electric hybrid SULEVs on the market today. The  classifications of ZEV, PZEV, or SULEV only refer to the air emissions, by the way — not the fuel efficiency. The EPA Green Vehicle Guide in the link below will allow you to look up vehicles and compare both emission and fuel efficiency characteristics. Remember that 2005 and 2006 trucks and Sport Utility Vehicles do not have the same standards and ratings as cars, so a SULEV Sport Utility Vehicle can pollute much more than a SULEV car.

ULEVs are ultra low-emission vehicles, somewhere between a SULEV and a LEV (low-emission vehicle). The current requirements for new model cars are so close to the LEV classification that many new car models are already LEVs or