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EPA Issues First Draft Staff Paper on Ground-Level Ozone

Release Date: 11/17/2005
Contact Information:

Contact: John Millett, 202-564-4355 /

(11/17/05) EPA is issuing an initial draft of the staff paper on ground-level ozone as part of a process to gather public, technical and scientific input to ensure that federal air quality standards reflect the latest air pollution and health effects research. The draft staff paper, "Review of the National Ambient Air Quality Standards for Ozone," includes scientific and technical information about ozone related health and welfare effects, initial results from a human exposure analysis and health risk assessment, and discussion of a planned vegetation-related environmental assessment.

This initial draft staff paper does not provide staff recommendations as to whether or not to change current standards; it is a preliminary step in a process required by the Clean Air Act to periodically assess the National Ambient Air Quality Standards. Development of the staff paper is the second step in this extensive scientific and technical assessment process. The first step in that process is the preparation of an Air Quality Criteria Document. The Criteria Document is a comprehensive assessment of scientific data about the health and environmental effects associated with the pollutant under review -- in this case, ozone. EPA's Office of Research and Development released the Second External Review Draft of the Ozone Criteria Document in August, 2005.

The Clean Air Act requires EPA to set National Ambient Air Quality Standards for ozone and five other major pollutants considered harmful to public health and the environment. The law also requires EPA to periodically review the standards to ensure that they provide adequate health and environmental protection, and to update those standards as necessary. EPA last updated the ozone standards in 1997.

The Clean Air Science Advisory Committee (CASAC), a Congressionally-mandated group of independent scientific and technical experts, will review the second external review draft Criteria Document and will provide a consultation on this initial draft of the Staff Paper at a meeting in Durham, N.C., on Dec. 6-8, 2005. This meeting is open to the public. EPA will carefully review and consider comments received during both the public comment period and the December CASAC meeting and anticipates release of a final Criteria Document in February 2006. EPA will revise the draft Staff Paper, taking into account CASAC and public comments, and anticipates release of the next draft in spring 2006.

The preliminary draft Staff Paper is available online at:
A fact sheet summarizing the first draft Staff Paper is available at: