Greenhouse Gases

• In April 2007 the Supreme Court ruled that the EPA violated the Clean Air Act by not regulating new vehicle greenhouse gas emissions. In 2010 the EPA implemented a rule applying to passenger cars and many trucks in model years 2012 through 2016, requiring vehicles to meet an average emissions level of 250 grams of carbon dioxide per mile.
  
  

California Standard

• In 2004 California enacted a landmark law requiring new vehicles to reduce their tailpipe emissions by one-third by 2016. California was allowed to set its own fuel emissions standards under the Clean Air Act with the federal government's approval.
  
  

Pollution Limits

• The EPA has different exhaust emissions standards according to how many miles a vehicle has been driven. For most passenger cars and lighter trucks, the EPA sets the following per-mile emissions limits at 50,000 miles: between 0.05 and 0.14 grams of nitrogen oxide; between 0.075 and 0.195 grams of nonmethane organic gas; between 3.4 and 5 grams of carbon monoxide; and between 0.015 and 0.022 grams of formaldehyde.