The Office of Compliance Fact Sheet Series

Updated March 1998 - Doc. No.: 1400

What is the Clean Air Act? The Clean Air Act (CAA) of 1970 set a national agenda for identifying areas of the nation with unhealthy air quality. It also established specific responsibilities for government and industry to promote healthy air quality nationwide. Twenty years later, the 1990 CAA Amendments (CAAA) clarified the direction for many of the established nationwide clean air programs and set out additional clean air program requirements deemed necessary to achieve the national agenda identified in 1970. The CAA consists of sections, known as Titles, which direct EPA to establish national standards for ambient air quality and for EPA and the States to implement, maintain, and enforce these standards through a variety of mechanisms. The CAA regulations appear in the Code of Federal Regulations (CFR) under 40 CFR Parts 50-99. The first six Titles are described below: Titles I and III: Under Title I of the CAA, EPA has established national ambient air quality standards (NAAQSs) to limit levels of six "criteria pollutants" (see box). Geographic areas that meet NAAQSs for a given pollutant are classified as attainment areas; those that do not meet NAAQSs are classified as non-attainment areas. Under §110 of the CAA, each State must develop a State Implementation Plan (SIP) to identify sources of air pollution and to determine what reductions are required to meet Federal air quality standards. In many instances, state regulations can be more stringent than the federal regulations and have additional requirements. Title I also authorizes EPA to establish New Source Performance Standards (NSPSs), which are nationally uniform emission standards for new stationary sources falling within particular industrial categories. NSPSs are based on the pollution control technology available to that industrial source but allow the affected industries the flexibility to devise a cost-effective means of reducing emissions. Under Title I, EPA establishes and enforces National Emission Standards for Hazardous Air Pollutants (NESHAPs), nationally uniform standards oriented towards controlling particular hazardous air pollutants (HAPs). Title III of the CAAA further directed EPA to develop a list of sources that emit any of 188 HAPs, and to develop regulations for these categories of sources. To date, EPA has listed 174 categories and developed a schedule for the establishment of emission standards. The emission standards will be developed for both new and existing sources based on "maximum achievable control technology" (MACT). The MACT is defined as the control technology achieving the maximum degree of reduction in the emission of the HAPs, taking into account cost and other factors. Title II: Title II pertains to mobile sources, such as cars, trucks, buses, and planes. Reformulated gasoline, automobile pollution control devices, and vapor recovery nozzles on gas pumps are a few of the mechanisms EPA uses to regulate mobile air emission sources. Title IV: Title IV establishes a sulfur dioxide emissions program designed to reduce the formation of acid rain. Reduction of sulfur dioxide releases will be obtained by granting to certain sources limited emissions allowances, which, beginning in 1995, will be set below previous levels of sulfur dioxide releases. Title V: Title V of the CAAA of 1990 created a permit program for all "major sources" (and certain other sources) regulated under the CAA. One purpose of the operating permit is to include in a single document all air emissions requirements that apply to a given facility. States are developing the permit programs in accordance with guidance and regulations from EPA. Once a State program is approved by EPA, permits will be issued and monitored by that State. Title VI: Title VI is intended to protect stratospheric ozone by phasing out the manufacture of ozone-depleting chemicals and restricting their use and distribution. Production of Class I substances, including 15 kinds of chlorofluorocarbons (CFCs), will be phased out entirely by the year 2000, while certain hydrochlorofluorocarbons (HCFCs) will be phased out by 2030. Do the Clean Air Act Regulations Apply to Me? Of the above mentioned CAA sections, the Titles that have the most direct impact on the transportation industry are Titles I, II, III, and V. Which CAA Titles and regulations apply to your business depends on whether you are operating a stationary or mobile air emission source. Stationary Sources: Titles I, III, and V apply to operators of major stationary sources of air pollutant emissions. These may include facilities such as repair and maintenance facilities, manufacturing and assembly plants, wholesale or bulk refueling points, engine testing facilities, or any other stationary source which operates within an owner's/operator's property boundary. The attainment or non-attainment status of an air quality region will determine the major stationary source emission thresholds for criteria air pollutants (see Title I). Depending on where the source is located, major stationary source thresholds may vary anywhere from emissions of 100 tons per year for any air pollutant in an attainment area, to 10 tons per year in extreme non-attainment areas. Operators of major stationary sources must install emission control technology on sources of air toxics pollutants regulated under Title III. Title V requires operators of major stationary sources to obtain a federal operating permit that must be renewed every five years or at the time of a major modification to the source.
Mobile Sources: Title II applies to owners, operators, and manufacturers of mobile sources such as cars, buses, trucks, and airplanes. Examples of some Title II programs include tighter tailpipe emission standards for passenger vehicles, cold temperature carbon monoxide standards, improved reformulated gasolines, reduced diesel particulate standards for urban buses, and clean fleet vehicle requirements for specific target areas across the country. In addition, the EPA Office of Mobile Sources has instituted transportation control measures and voluntary programs for commuters. Additional Information Publications: For additional information on air emission requirements, please consult the following publications:

Contacts: Additional Information is available from the following sources: General information regarding EPA - http://www.epa.gov

EPA's Office of Mobile Sources - http://www.epa.gov/OMSWWW/omshome.htm