Simplified Historic Note: The Clean Air Act was enacted in its modern form in 1970.  It has gone through two major revisions since its passage, both of which were motivated by frustration with the nation's ability to achieve "clean air".  The basic structure of the law is that the Administrator of the United States Environmental Protection Agency sets national ambient air quality standards (NAAQS) which are supposed to assure protection of human health and the environment, and the states are given the opportunity to submit state implementation plans (SIPs) that are designed to achieve and maintain the NAAQS within their borders.  Failure of a state to submit an adequate plan may trigger sanctions (e.g. withdrawal of program funds), and it may lead to implementation of a plan by the USEPA (FIP) to correct the deficiencies.   In most areas of the country, there has been attainment of NAAQS or progress toward the attainment and maintenance of NAAQS for sulfur oxides, nitrogen oxides, carbon monoxide, particulate matter and ozone.  Nevertheless, in many areas, especially urbanized areas, violations of the Ozone standard are recurrent.

The 1990 Revision:  In 1990, the law was changed to require every major source of air pollutant emissions to obtain an operating permit.  The permit program requirements are mostly contained in Title V of the Clean Air Act, and the permits are commonly called "Title V" permits.  The definition of sources that are major is complicated.  It generally includes sources that are "major" for conventional pollutants or or hazardous air pollutants (HAPs).  What is a major emission will vary depending on the source's location (e.g. is it in an "attainment area" or a "non-attainment area"), the kind of facility (e.g. is it a coal-fired boiler or a furniture coating line, etc.), the date of construction or modification of the facility, and the pollutants emitted.

    The 1990 law also saw the implementation of a comprehensive hazardous air pollutant control program.  Some 185 specific chemical compounds are identified as HAPs at Section 112 of the Act.  EPA has been engaged in a process of issuing industry-by-industry rules setting "maximum achievable control technology" standards (MACT), which must be complied with by all new plants in a subject category upon construction, and with which there must be compliance by existing major MACT sources within three years of promulgation.  A "major" MACT source is one at which ten or more tons per year of a single HAP or 25 or more tons per year of any combination of HAPs are emitted.

Current Issues:  Numerous public policy and economic issues are involved in Clean Air Act implementation. The issues most commonly encountered by a business subject to the Act's requirements are:

    1) Specific Terms of Title V Permits

Under the Title V program, a permit application is subject to State review and approval wherever a State has qualified with EPA to administer the permit program. The program requires public notice and the opportunity for comment or public hearing prior to issuance of the permit.  Additionally, USEPA has the opportunity and authority to review a permit prior to issuance and to veto it if it is not adequate.  This process of review has taken longer than most states or the EPA originally planned.  It is essential for permit applicants to follow the progress of their permits.  There is only a limited period of time in which to make an expanded record in the event of public or EPA opposition to a permit being issued.  In most cases, permits are issued after negotiation.

    2) Revisitation of New Source Issues

One of the issues that is sometimes involved in permit review is a review of whether the source properly obtained new source review during its history of building and expansion.  This has been a controversial subject, due in part to indications early in the program implementation that a "look back" longer than five years was counterproductive to the idea of getting all sources under a permit. Some States have questioned recent EPA insistence on attention to whether proper new source review occurred early in the history of a given source.  This complicates and typically delays permit review and issuance.

    3) Relocation/Expansion Issues

Non-attainment:  In order for a new major source to be located in a non-attainment area, it must utilize a very high degree of control technology and provide offsets of its planned emissions.  The amount of offsets varies with the degree of nonattainment at the proposed site location.  Similarly, a problem for sources in non-attainment areas is that the relocation or move of production equipment to a new site is deemed by EPA to create a "new source".  Generally, new sources in non-attainment areas must achieve a strict level of control, which is the stricter of Lowest Achievable Emission Rate (LAER) or new source performance standards (NSPS), provide offsets, and demonstrate compliance exists at any other facilities operated by the permittee in the region. 

Attainment areas:  The rules are somewhat different in "attainment" areas, where "Prevention of Significant Deterioration" (PSD) standards apply to new sources and to sources deemed new due to significant modification or reconstruction.  For some pollutants, a considerable amount of monitoring data must be obtained or available in pursuing a PSD application.  The PSD process takes account of existing air quality and allows only a limited incremental reduction that will not interfere with maintenance of air quality standards.