	Introduction

		The Role of NAAQS in Air Quality Regulation

Setting National Ambient Air Quality Standards (NAAQS) is an action that is at the core of the Clean Air Act. CASAC has seven members, largely from academia and from private research institutions, who generally serve for two consecutive three-year terms. In conducting NAAQS reviews, their expertise is supplemented by panels of the nation's leading experts on the health and environmental effects of the specific pollutants that are under review. CASAC panels had a nearly 30-year history of working quietly in the background, advising the agency's staff on NAAQS reviews, and issuing what were called "closure letters" on the agency documents that summarize the science and the policy options behind the NAAQS. The science and policy documents, written by EPA staff, generally have gone through several iterations before the scientists were satisfied, but, with the issuance of a closure letter, CASAC has in past years removed itself from the process, leaving the formal proposal and final choice of standards to the Administrator. The committee took the unprecedented steps of writing to the Administrator both after he proposed the standards in January, and after he promulgated them in September. In the latter communication, CASAC stated unanimously that the Administrator's action " does not provide an ' adequate margin of safety ... requisite to protect the public health ' (as required by the Clean Air Act) ...." (Italics in original.) A month after CASAC's challenge to the final particulate decision, CASAC's ozone review panel took an unusually strong stand regarding review of that NAAQS. The panel approved EPA's policy options paper (or "Staff Paper"), the next-to-last formal step before the Administrator proposes revision of the ozone NAAQS, but in doing so it stated, "There is no scientific justification for retaining the current primary 8-hr NAAQS ...," and it recommended a range for the revised standard that would be substantially more stringent than the current standard. The Administrator proposed a revision generally outside CASAC's range on June 20, 2007, and in March 2008 he promulgated new ozone standards that were outside CASAC's range. It also reviews various proposals for change that have been discussed, including EPA's December 2006 modifications. Role of CASAC . As the Executive Summary noted:
Past reviews of the process have addressed a number of issues, including the difficulty EPA has had historically in completing NAAQS reviews at five-year intervals as required by the CAA, resulting in litigation-driven review schedules; the statutory role of the Clean Air Scientific Advisory Committee (CASAC) in providing scientific and policy-relevant advice to the Administrator; concerns about the "encyclopedic" nature of EPA's science assessment documents (referred to as "Criteria Documents") and support for a more integrative synthesis of the science; and general support for the introduction and subsequent evolution of a policy-oriented "Staff Paper" to help bridge the gap between the science presented in the Criteria Document and the policy judgments required of the Administrator in reaching decisions on the NAAQS. In its May 12, 2006, letter to the EPA Administrator, CASAC raised this point. This mollified some of CASAC's concerns, but CASAC has continued to express "serious concerns" about other aspects of the Lead NAAQS review.
As the Environmental Protection Agency (EPA) completes its reviews of the ozone, particulate matter (PM), and lead air quality standards—the PM review was completed in September 2006, the ozone review in March 2008, and the lead review is due for completion in September 2008—the Clean Air Scientific Advisory Committee (CASAC), an independent committee of scientists that advises the agency's Administrator, has been sharply critical of several of EPA's decisions.
CASAC was established by statute in 1977. Its members, largely from academia and from private research institutes, are appointed by the EPA Administrator. They review the agency's work in setting National Ambient Air Quality Standards (NAAQS), relying on panels of the nation's leading experts on the health and environmental effects of the specific pollutants. CASAC panels have a nearly 30-year history of working quietly in the background, issuing what were called "closure letters" on agency documents that summarize the science and the policy options behind the NAAQS. The science and policy documents, written by EPA staff, generally have gone through several iterations before the scientists were satisfied, but, with the issuance of a closure letter, CASAC has in past years removed itself from the process, leaving the final choice of standards to the Administrator.
In 2006, however, CASAC and its 22-member PM Review Panel forcefully objected to the Administrator's decisions regarding revision of the particulate NAAQS. The committee took the unprecedented steps of writing to the Administrator both after he proposed the standards in January, and after he promulgated them in September. In the latter communication, CASAC stated unanimously that the Administrator's action "does not provide an 'adequate margin of safety ... requisite to protect the public health' (as required by the Clean Air Act) ...." (Italics in original)
Within a month of CASAC's September 2006 letter, the committee's ozone review panel approved EPA's policy options Staff Paper, the next-to-last formal step before the Administrator proposed to revise the ozone NAAQS. In doing so, the panel drew a firm line ("There is no scientific justification for retaining the current primary 8-hr NAAQS"), and recommended a range far more stringent than the previous standard. The Administrator promulgated a standard outside of CASAC's range in March 2008.
At the same time that CASAC panels were speaking out, EPA was conducting a review of CASAC's role and other aspects of the NAAQS-revision process. A December 7, 2006 EPA memorandum made a number of changes in that process that many argue will diminish the role of CASAC and agency scientists. As the changes have been implemented, CASAC has objected to some of the new procedures and a number of Senators have written the EPA Administrator to express their opposition to the changes. Congress is expected to continue taking an interest in the subject. This report discusses these issues, focusing on the statutory and historical role of CASAC and various proposals for change.