EPA’s Frequently Asked Questions about
Fuel Economy and Emission Standards

What are EPA’s emission standards and why are they important?
Cars, trucks and other mobile sources account for almost a third of the total air pollution in the United States. Over the years, emission standards for cars and trucks have been strengthened to address this national air quality problem. The emission standards are in effect from the time the vehicle is produced until the vehicle reaches the end of its useful life – manufacturers are responsible for selling cars that will pollute no more than the emission standard limits.