What 1970 U.S. law addressing air pollution was passed following Earth Day?

The 1970 U.S. law addressing air pollution was the Clean Air Act of 1970.

Often called the Clean Air Act Amendments of 1970, the law dramatically expanded the federal government’s role in controlling air pollution. It authorized national ambient air-quality standards, requirements for state implementation plans, controls on emissions from new sources, and limits on hazardous air pollutants.

President Richard Nixon signed the measure on December 31, 1970, several months after the first Earth Day. The event did not single-handedly write the law, but its enormous public response helped create political momentum for a wave of environmental action. The Environmental Protection Agency began operating on December 2, 1970, and became central to implementing the new requirements.

The Clean Water Act followed in 1972, while the Endangered Species Act became law in 1973. The National Environmental Policy Act was also enacted in 1970, but it addressed environmental review broadly rather than serving as the principal 1970 federal air-pollution law.