Introduction to this module

Cars are regulated on the amount of emissions they are allowed to emit. The 1990 Clean Air Act is a federal law covering the entire country, although the states do much of the work to carry out the Act. Under this law, the Environmental Protection Agency sets limits on how much of a pollutant can be in the air anywhere in the United States. This ensures that all Americans have the same basic health and environmental protections. The law allows individual states to have stronger pollution controls, but not weaker controls than those set for the whole country.