Clean Air Act Explained: A Brief History of the Clean Air Act

The Clean Air Act is a 1963 act of Congress that became federal law when signed by President Lyndon Johnson. At the time of its signing, the bill text was the most substantive attempt by the U.S. federal government to establish air pollution limits on U.S. industry, power plants, and transportation including motor vehicles.

The Clean Air Act set national standards designed to promote cleaner air and combat public health threats. It identified pollutants and set primary standards for their use, with the understanding that local governments would enforce emission standards set at the national level. The act mandated that the best available control technology be deployed to limit the emission of pollutants, toxic chemicals, and volatile organic compounds.

Over the years, legislators have made major revisions to the Clean Air Act, applying the best practices of the eras in which they were passed.

• 1955: The 1963 Clean Air Act was preceded by the Air Pollution Control Act of 1955. Yet this 1955 law did not include a role for the federal government in regulating pollution; it relied on state and local governments to set emissions standards and improve air quality standards.
• 1963: Congress passed the Clean Air Act, which was then signed into law by President Lyndon Johnson. The 1963 law was the first to introduce new regulations specifically enforced by the federal government.
• 1967: The Air Quality Act enhanced federal regulation of interstate polluters.
• 1970: An amendment to the Clean Air Act set new limits for motor vehicle emissions, submitting mobile sources of air pollution to the same scrutiny applied to stationary sources like power plants. The 1970 revision established State Implementation Plans (SIPs) to enforce standard-setting. It set limits on hydrocarbons (better known as fossil fuels), photochemical oxidants, carbon monoxide, nitrogen oxides (particularly nitrogen dioxide), sulfur dioxide, and particulate matter. It also established the National Ambient Air Quality Standards (NAAQS). Many of these regulations would be overseen by the newly created Environmental Protection Agency (EPA). The first EPA administrator, William Ruckelshaus, took office on December 4, 1970.
• 1977: An amendment to the 1963 act added a focus on non-attainment areas—regions that had not met government standards and still experienced unhealthy levels of air pollution.
• 1990: The 1990 amendment identified coal plants as major sources of the nitrogen oxides and sulfur dioxide that create acid rain. It also focused on depletion of the stratospheric ozone layer and provided a major increase in enforcement powers for governments. It established a cap-and-trade program that limited total emissions but still allowed polluters to trade credits and purchase the right to increase their own emissions.
• 2011: Beginning in 2011, the Environmental Protection Agency under President Barack Obama applied Clean Air Act standards to greenhouse gas pollution linked to human-made climate change. Subsequently, the EPA of President Donald Trump’s administration limited this focus on carbon pollution and greenhouse gas emissions.

The Clean Air Act’s rules are enforced by federal agencies, particularly the Environmental Protection Agency (EPA), which is run by a politically appointed EPA administrator. Under the federal system of government, the EPA also relies on State Implementation Plans (SIPs) to enact its policies on a state-by-state basis.

In practice, many states set standards that exceed those laid out by federal programs like the Clean Air Act. The state of California, for instance, has stricter rules than the federal government regarding the adoption of alternative fuels for cars and light trucks. Meanwhile, environmental groups have lobbied state and local governments for environmental regulations that outpace federal law.

The Clean Air Act’s regulations mandate that newly built pollution emitters adhere to new source performance standards (a type of pollution control standards) that protect public welfare. The act also includes a list of hazardous air pollutants and establishes air quality control regions called attainment areas. These areas are intended to protect the public from dangerous particulate matter and volatile chemicals linked to poor health and premature deaths.

The significant changes imposed by this comprehensive federal law, as well as subsequent updates in later federal legislation, led to reductions in common pollutants, toxic air pollution, ground-level ozone, and lead pollution. A 2018 study estimated that the initial act, along with Clean Air Act amendments, could be linked to a 60 percent reduction in manufacturing industry pollution between 1990 and 2008.

Get the MasterClass Annual Membership for exclusive access to video lessons taught by masters, including Jane Goodall, Bill Nye, Neil deGrasse Tyson, Paul Krugman, and more.