Particulate Matter Air Quality Standards: Background and Current Developments

Publication Date: January 2005

Publisher: Library of Congress. Congressional Research Service

Author(s):

Research Area: Environment

Type:

Abstract:

The Environmental Protection Agency (EPA) is nearing completion of its review of contentious air quality standards for particulate matter (PM), with final action expected in late 2005. The current standards are among the most far-reaching regulations on EPA's agenda. Promulgated in 1997, but only now being implemented, the standards could potentially prevent the loss of thousands of lives annually at an annual cost estimated by the agency to be $8.6 billion.

The Clean Air Act (CAA, Sections 108 and 109) requires that air quality criteria used in determining National Ambient Air Quality Standards (NAAQS) reflect the latest scientific information. The act includes provisions for the periodic review and revision, as appropriate, of existing criteria and standards. It is this periodic review process that is nearing completion. In October 2004, EPA released Air Quality Criteria for Particulate Matter, reflecting the agency's synthesis of relevant PM research conducted since the agency's last review, completed in 1996. This report, referred to as a "criteria document," will provide the scientific basis for assessments and policy decisions regarding the adequacy of the current PM NAAQS. Further decisions, including recommendations regarding the standards, are expected early in 2005, following the release of what is referred to as a "staff paper."

Meanwhile, EPA is continuing implementation of the 1997 particulate matter standards, which had been delayed several years by litigation and other factors. On January 5, 2005, EPA published the final designations of geographical areas for the fine particulate matter or "PM2.5" (particles less than 2.5 micrometers in diameter) NAAQS. EPA designated 225 counties in 20 states, and the District of Columbia, as "nonattainment areas"; those areas with (or contributing to) air quality levels exceeding the annual and 24-hour PM2.5 standards.

Congress and a wide variety of stakeholders have closely followed the evolution and development of PM NAAQS. In 1997, when the current standards were promulgated, Congress held 28 days of hearings on the EPA rule. Subsequently, more than 100 plaintiffs sued to overturn the standards. This litigation went to the Supreme Court before being resolved, largely in EPA's favor, in February 2001.

Since FY1998, in an effort to expedite research and strengthen the science underlying EPA's review of the standards, Congress has appropriated funding specifically for PM research annually ($62 million for FY2005). The research, including re-analysis of key studies underlying the 1997 standards, has largely confirmed EPA's earlier conclusions, although new questions have been raised regarding the methodology used in some of the studies. The National Academy of Sciences (NAS) has issued four reports on the state of PM research at EPA, and EPA released a report reviewing its five-year progress of PM research. Because of the potential impacts particulate matter standards could have on both public health and the economy, EPA's reassessment of the PM standards will likely be of continued interest to Congress. This report will be updated as events warrant.