Clean Air Act

The Clean Air Act is a federal law, the purpose of which being to regulate air pollution throughout the United States. The Clean Air Act is one of the most inclusive laws pertaining to air quality in the world. For example, the Clean Air Act protects the ozone layer by providing information to people to help them understand how it forms and diminishes. To explore this concept, consider the following Clean Air Act definition.

Definition of Clean Air Act


  1. A federal law that the government passed as a way to regulate air pollution in the United States.



Clean Air Act of 1970

The Clean Air Act of 1970 caused a major change in how the federal government chose to approach the regulation of air pollution. For example, the Clean Air Act gave both federal and state governments permission to regulate emissions from stationary sources (like industrial plants), as well as mobile sources, like cars. As a result, the government implemented four major programs to regulate stationary sources:

  • National Ambient Air Quality Standards (NAAQS”)
  • State Implementation Plans (SIPs)
  • New Source Performance Standards (NSPS)
  • National Emission Standards for Hazardous Air Pollutants (NESHAPs)

The birth of this legislation coincided with the formation of the National Environmental Policy Act. This is the law responsible for creating the Environmental Protection Agency (EPA) we know today. The government formed the EPA in December of 1970, specifically to implement the requirements provided by these newly created Acts.

Amendments Made in 1977

For many major laws, officials create amendments to clear up things that may not have been clear before. Officials also create amendments to compensate for provisions that they did not initially include in the law by adding them in later. As far as the Clean Air Act is concerned, the amendments made in 1977 affected states that were not meeting the goals set for them by the Act. These goals concerned both vehicular emissions and the prevention of the deterioration of air quality in areas that had never had a problem before.

1990 Amendment

The last amendment the government made to the Clean Air Act thus far took place in 1990. The 1990 amendment addressed certain environmental issues, like:

  • Acid rain
  • Toxic pollutants
  • Areas that were still not meeting their goals, despite the 1977 amendments
  • Ozone layer depletion

The government directed states to implement massive decreases in gas emissions as a method of controlling acid rain. The government also increased the regulation of toxic pollutants and implemented deadlines for those areas that had not been meeting the goals of the Clean Air Act. Further, three major contributors to the depletion of the ozone layer met their end.

Some of the more notable provisions of the 1990 amendment included:

  • The promotion of the use of clean coal and natural gas, as well as new technologies that could clean coal
  • The creation of a clean fuels market for those fuels derived from grain and natural gas. (The government created this goal as a way to reduce the country’s dependency on oil imports by one million barrels per day.)
  • The creation of energy conservation programs that allow customers to obtain emission reductions

Clean Air Act Example Involving Massachusetts and the EPA

An example of the Clean Air Act that also involves the Environmental Protection Agency (EPA) is Massachusetts v. Environmental Protection Agency. The Supreme Court heard this case in 2007. Here, Massachusetts, along with several other states, petitioned the EPA, asking them to regular vehicular emissions like carbon dioxide. The purpose in doing so was to prevent new cars from contributing to global warming.

Massachusetts argued that the law required the EPA to regulate “greenhouse gases.” The Clean Air Act requires Congress to regulate any air pollutant that has the potential to endanger the public’s health. The EPA denied the states’ petition, claiming they did not, in fact, have the authority to regulate these emissions. And even if they did, the EPA argued, they would need more time to research the impact, if any, that such emissions could have on climate change. They would also need to research any available options that could solve the problem.

Appeal and the Supreme Court

Massachusetts appealed the EPA’s denial to the Court of Appeals for the D.C. Circuit. However, the state lost when the panel found in the EPA’s favor. The state then filed a writ of certiorari with the U.S. Supreme Court, and the Court agreed to hear the case.

The Court then had to rule on two questions:

  1. Can the EPA decline to create motor vehicle emissions standards based on policies not reflected in the Clean Air Act?
  2. Does the Clean Air Act actually give the EPA the authority to regulate greenhouse gases?

In a 5 – 4 vote, the Court ruled in Massachusetts’ favor. The Court held that Massachusetts had the right to file suit against the EPA over the potential harm they could suffer from global warming. Further, the Court disagreed with the EPA on the latter’s belief that they lacked the authority to act. Those who wrote the Clean Air Act used language intended to cover all bases and be timeless.

Excerpt from the Court’s Decision

Said the Court, in its Decision with respect to this case:

“Given EPA’s failure to dispute the existence of a causal connection between man-made greenhouse gas emissions and global warming, its refusal to regulate such emissions, at a minimum, ‘contributes’ to Massachusetts’ injuries. EPA overstates its case in arguing that its decision not to regulate contributes so insignificantly to petitioners’ injuries that it cannot be hauled into federal court, and that there is no realistic possibility that the relief sought would mitigate global climate change and remedy petitioners’ injuries, especially since predicted increases in emissions from China, India, and other developing nations will likely offset any marginal domestic decrease EPA regulation could bring about.

Agencies, like legislatures, do not generally resolve massive problems in one fell swoop, (citation omitted), but instead whittle away over time, refining their approach as circumstances change and they develop a more nuanced understanding of how best to proceed, (citation omitted). That a first step might be tentative does not by itself negate federal-court jurisdiction. And reducing domestic automobile emissions is hardly tentative. Leaving aside the other greenhouse gases, the record indicates that the U. S. transportation sector emits an enormous quantity of carbon dioxide into the atmosphere.”

Related Legal Terms and Issues

  • Writ of Certiorari – An order issued by a higher court demanding a lower court forward all records of a specific case for review.