Understanding Environmental Law: The Clean Air Act

By Alyna Sigel

The Clean Air Act is, to this day, one of the most important pieces of environmental legislation passed in the United States. This statute has allowed for significant improvements in air quality that are beneficial to humans, wildlife, and marine life. Leading up to 1970, the air of many large cities in the nation was filled with smog, and environmental movements were gaining momentum. When the CAA was passed in 1970, it granted the EPA the authority it needed to take meaningful steps to fight pollution. The EPA uses this law to set limits on the amount of certain air pollutants allowed in the U.S. It is important to note that the CAA has been amended twice since its passage in 1977 and again in 1990.

To better understand how the Clean Air Act is implemented, it is necessary to explain its most relevant sections. The basis of the act is found in Sections 108 and 109. Section 108 establishes Air Quality Criteria and Control Techniques. Under this section, the EPA is able to establish a list of “criteria” air pollutants, which are pollutants that meet certain criteria. These criteria state that the emissions of the pollutant may endanger public health or welfare, are emitted by numerous or diverse sources, and there are no previously issued air quality criteria for it. To date, only six pollutants have been added to this list. These pollutants are ground-level ozone, carbon monoxide, sulfur dioxide, particulate matter, lead, and nitrogen dioxide. 

After a pollutant is identified as a “criteria” pollutant, Section 109 explains the next steps. The EPA must adapt National Ambient Air Quality Standards (NAAQS) for each of the pollutants. This is the maximum amount of the pollutant that can be found in a cubic meter of outdoor air anywhere in the United States. The EPA sets both national primary air quality standards and national secondary air quality standards. National primary air quality standards are based on the amount to avoid risks to human health with a margin of safety, while national secondary air quality standards are set to avoid risks to human welfare. When an area does not meet the NAAQS, it is considered an area of nonattainment.  

Using the basis provided by these sections, Sections 172 and 173 detail the action of the Clean Air Act, with a focus on this concept of nonattainment. Section 172(c) covers nonattainment plan provisions and is broken down into nine categories, the most relevant of which are the first, second, and fifth. The first establishes that all existing sources of criteria pollutants in nonattainment areas must implement, at a minimum, reasonably available control technology (RACT). The second states that reasonable further progress is required to track improvements toward reaching attainment. The fifth focuses on major new and modified stationary sources; it sets a requirement for a federal permit before building a new or modified source that will emit at least 100 tonnes of a criteria pollutant per year in a nonattainment area. 

The process of receiving a permit is outlined in Section 173. First, before the source is to commence operation, offsets of the nonattainment criteria pollutant must be obtained at a 1:1 ratio. In other words, for every tonne of the pollutant the source emits, one tonne of the same pollutant must be purchased in offsets. Next, the source must comply with the lowest achievable emission rate. Additionally, all other sources the owner or operator has within the state of the new source must meet all standards in the Clean Air Act, such as having implemented RACTs. The state must also have a plan that is effective and enforced for meeting the CAA regulations. Finally, before being considered, permit seekers must analyze various factors, including alternative sites, environmental costs, and social costs. 

The necessity to meet these requirements before permit consideration inherently results in further benefits. New or modified must be net-zero for the “criteria” pollutant emitted. It requires that existing sites meet the regulations, which is not always the case before the need for a permit. The final requirement also allows leeway to reject a permit and prevent the build or expansion.

Since the implementation of the Clean Air Act, there have been many notable improvements to air quality, human health, and environmental health in the United States. Emissions of “critical” pollutants have substantially decreased, some by over 70%. This has resulted in decreased risks of lung complications and increased life quality. Limiting air pollution benefits plants by decreasing soil nutrient deterioration, which helps to sustain ecosystems. Nitrogen dioxide emissions deplete oxygen in coastal areas, so the impacts of the act are extremely positive for marine life. 

By understanding the Clean Air Act, we understand our right to clean air. This allows the public to hold individuals accountable, thereby protecting human, environmental, and marine health and welfare. The benefits of this act are undeniable. It is one of the most impactful pieces of environmental legislation to be passed in the United States, and it is exemplary of the benefits that environmental policies can provide.

Citations

1. Phase Associates. (n.d.). Clean Air Act (CAA) & Its Impact On Air Quality Today. Phase Associate. https://phaseassociate.com/blog-post/clean-air-act-impact-on-air-quality/

2. United States. (1970). Clean Air Act, 42 U.S.C. § 7401 et seq. (1970).

3. US EPA. (2017, January 19). Criteria Air Pollutants. United States Environmental Protection Agency. https://19january2017snapshot.epa.gov/criteria-air-pollutants_.html

4. US EPA. (2018, November 21). Clean Air Act requirements and history. United States Environmental Protection Agency. https://www.epa.gov/clean-air-act-overview/clean-air-act-requirements-and-history