The Clean Air Act (CAA) is actually a series of amendments made to the 1967 Air Quality Act. Significant amendments occurred in 1970, 1977, and 1990.
The 1970 Clean Air Act Amendments directed EPA to identify acceptable levels of selected air pollutants that would protect human health. CAA required that each state create a state implementation program (SIP) outlining the controls that would attain these levels. However, even with these controls, many regions did not achieve the desired levels of clean air. Consequently, in the 1990 amendments, Congress specified timeframes for attainment of these air pollution levels.
The 1990 amendments also created a permitting program and added additional requirements for other air pollution issues, such as acid rain, destruction of the ozone layer, and air toxics. The amendments continued to allow the states to implement CAA through their SIPs, but extended enforcement powers to both the states and the EPA. The federal regulations for implementing these requirements are in 40 CFR Subchapter C, Parts 50–99.
To enforce CAA, EPA compares levels of air pollutants across the country to standards it has established as protective of human health and the environment. The level of permitting and control technology required on campus air pollution sources depends on whether its geographic region has air pollution below the levels determined by EPA.
Key Concepts
Criteria Pollutants
Criteria pollutants are six common pollutants found in all communities that come from a variety of sources. The criteria pollutants list consists of ozone, carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter (PM10), and lead.
National Ambient Air Quality Standards (NAAQS), Primary and Secondary
CAA established two thresholds of national ambient air quality standards, or NAAQS, for the six criteria pollutants. “Primary” standards establish limits to protect public health, including the health of “sensitive” populations such as asthmatics, children, and the elderly. “Secondary” air quality standards set limits to protect public welfare, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. With the exception of carbon monoxide and sulfur dioxide, EPA set the primary and secondary standards at the same levels.
Hazardous Air Pollutants (HAPs)
EPA has developed a list of “hazardous air pollutants” that are known to or may cause serious health problems. This list includes about 190 organic compounds and heavy metals.
Attainment Area
These are places where air pollution levels do not exceed permissible levels for any criteria pollutants.
Nonattainment Area
Geographic regions where levels of air pollution exceed permissible levels for one or more pollutants are nonattainment areas. Many major cities are nonattainment areas for at least one criteria pollutant. 40 CFR 81 lists nonattainment areas.
Potential to Emit (PTE)
The maximum amount of emissions a source could possibly produce determines the CAA permit requirements. This maximum comes from a calculation based on the source equipment operating at maximum capacity, 24 hours per day, 365 days per year. If a source is dual-fuel capable, the PTE comes from the fuel that produces that higher level of emissions. PTE always exceeds actual emissions.
Ozone-Depleting Compounds (ODCs)
These are substances that may cause depletion of stratospheric ozone. Chlorofluorocarbons (CFCs or freons) are the most common of these substances.
Risk Management Plans
Facilities must create a risk management plan if they store or use large amounts of any of 77 specific chemicals. This plan must include risk analysis of a release and the effects of such a release on the local community.
Stationary Sources Versus Mobile Sources
Under the CAA, different rules apply to transportation (mobile) sources than apply to sources used standing still (stationary). Car, bus, and tractor engines are mobile sources. Boilers, furnaces, and generators are stationary sources. Portable sources (e.g., generators) are “stationary sources,” even though they can move.
Emissions Inventory
This is a list of emissions sources and estimates of emissions from these sources.
Does this apply to my campus?
Yes. The CAA applies to campus operations. Your specific requirements depend on the local attainment or nonattainment status. Campus operations that are regulated under the various programs of the CAA, or that may produce regulated emissions, include
- boilers, emergency generators, and other combustion sources;
- bakeries;
- paint booths;
- book preservation operations;
- degreasing operations;
- petroleum storage tanks;
- art studios and other production facilities;
- fleet vehicles;
- lawn care equipment;
- chillers and HVAC equipment;
- wastewater treatment plants;
- swimming pools disinfected with chlorine gas; and
- ammonia refrigeration plants.
What do I have to do?
Refer to the specific program summaries (Clean Air Act — Criteria Pollutants, Clean Air Act — Air Toxics, Clean Air Act — Permitting, Clean Air Act — Mobile Sources, Clean Air Act — Risk Management Plans, and Clean Air Act — Ozone-Depleting Compounds) to determine compliance requirements.
Performing an emissions inventory of larger air pollution sources creates a database of information that will help when determining other compliance requirements. Often, measuring emissions or performing a PTE calculation is the only way to determine emissions. An EPA document called AP-42 predicts emissions of pollutants based on a variety of factors.