• The CAA is divided into seven distinct titles.

The Clean Air Act (CAA) is divided into seven distinct titles that address different air pollution criteria, permitting, and enforcement.

• Title I — Air pollution prevention and control includes provisions for attaining and maintaining the national ambient air quality standards (NAAQS). The Environmental Protection Agency (EPA) has used health-based criteria in order to set the allowable limits for common air pollutants, known as criteria air pollutants. The agency then developed a primary standard in order to protect human health, and a secondary standard in order to prevent environmental and property damage. An area that meets the primary standards is called an attainment area. An area that does not meet the primary standards is called a nonattainment area. Depending upon the degree to which a nonattainment area exceeds the standard, that area will be required to implement various control programs and achieve attainment of the NAAQS within a specified time frame. Also in Title I, is the requirement for reasonably available control technology (RACT). Stationary sources must use RACT to control air emissions. Mobile source control measures include vehicle inspection and maintenance (I/M) programs to reduce carbon monoxide and precursors to ozone. Last, Title I requires states to develop State Implementation Plans (SIPs) that explain how a state will comply with the CAA. The EPA must approve the SIP for the state to have authority to enforce the CAA.
• Title II – Emission standards for moving sources establishes requirements for mobile sources, including tailpipe emissions standards for hydrocarbons, carbon monoxide, and nitrogen oxides. Title II also requires tailpipe standards for carbon monoxide under cold temperature conditions, and cleaner gasoline to be used in U.S. cities with the worst ozone problems. The EPA is required to develop regulations on the general fleet program and credits program, and is also required to issue regulations with respect to converting conventional vehicles to clean fuel vehicles.
• Title III – Hazardous air pollutants (HAPs) identifies 187 air pollutants suspected of causing cancer or health problems and authorizes the EPA to identify sources and set required, technology-based controls to reduce these emissions. For each listed source category, the EPA will issue standards requiring the maximum degree of emissions reduction that has been demonstrated to be achievable. These are commonly referred to as maximum achievable control technology (MACT) standards. Title III also includes provisions to prevent accidental releases of hazardous pollutants. Any facility at which a listed pollutant is present at greater than a threshold quantity is required to prepare and implement a risk management plan (RMP). The plan must address how the facility will detect and prevent, or minimize, accidental releases. This title also created the Chemical Safety and Hazard Investigation Board (CSB), an independent safety board responsible for investigating any accidental release that results in a fatality or substantial property damage.
• Title IV – Acid deposition control addresses the control of pollutants associated with acid rain. The goal of this title is to achieve a 10-million-ton reduction of sulfur dioxide and an approximate 2-million-ton reduction in nitrogen oxides (relative to 1980 levels).
• Title V – Operating permits establishes the major source, federal permitting program. The Act enables states to collect permit fees from affected sources to cover reasonable direct and indirect operating costs for the permit program. A permit is to be issued for a fixed term, not to exceed five years. Though administration will be conducted by states with approved programs, the EPA will still assume federal oversight responsibilities and all permits will be subject to public comment. Title V also includes a provision requiring states to establish, as part of their SIP, a small business stationary source technical and environmental compliance assistance program.
• Title VI – Stratospheric ozone protection expands upon the Revised Montreal Protocol that was negotiated by the United States to address the depletion of the ozone layer. The law requires a complete phase-out of chlorofluorocarbons (CFCs) and halons with interim reductions. Ozone-depleting substances are to be grouped into two classes. Class I chemicals (CFCs, halons, carbon tetrachloride, and methyl chloroform) were to be entirely phased out by 2002. Class II chemicals (hydrochlorofluorocarbons) will be phased out by 2030.
• Title VII – Provisions relating to enforcement provide for felony penalties for knowing violations of the CAA and misdemeanor penalties for negligent releases of hazardous pollutants. The EPA can issue administrative enforcement penalties orders of up to $200,000 and administrative orders with compliance schedules of up to 12 months. The agency also has the authority to establish through regulation a field citation program for minor violations, where citations may be issued onsite during an inspection for up to $5,000 per day of violation. This law significantly expands a citizen’s authority to enforce CAA requirements, and citizen suits may include the assessment of civil penalties. The law also permits monetary awards of up to $10,000 to be made to citizens who provide information leading to a criminal conviction or a civil penalty.