The amount of smog a car puts into the air depends essentially on which emission standards it meets. (See “What are emission standards?” below.) It can also be affected by how you drive and maintain the car, how much fuel the car use, and the manner of fuel used.
Passenger cars must meet certain fuel mileage standards. Generally, the better the fuel mileage, the “cleaner” the car. For example, smaller cars typically get the best fuel mileage, which also means they pollute less.
Light trucks – which include vans, small pickup trucks, a
nd sport utility vehicles (SUVs)– are allowed to get lower fuel mileage than passenger cars. As a result, the average light truck pollutes more than the average car.
Some of the heaviest light trucks, such as large SUVs, do not have to meet any mileage standards. They are among the most polluting vehicles..
Emission standards
Emission standards limit the amount of pollution coming from a vehicle. All new vehicles for sale in the United States meet either federal emission standards (set by the U.S. Environmental Protection Agency), or California standards (set by the California Air Resources Board). The California standards are stricter than the federal standards
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