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Area Designations for 1997 Fine Particle (PM2.5) Standards

Review of the PM Standards

Information provided for informational purposes only Note: EPA no longer updates this information, but it may be useful for historical purposes. See the PM Designations Home Page for more recent information about PM Designations.

About the Review

EPA reviews its national outdoor air quality standards on periodic basis. We anticipate completing the current review (of the PM2.5 and PM10 standards) by September 2006.

Two documents are key in the review process: a criteria document, which is an exhaustive compilation of the latest scientific knowledge useful for assessing the health and welfare effects of the air pollutant; and a staff paper - a paper compiled by technical staff that helps translate the science into terms that can be used for making policy decisions.

Before either the criteria document or staff paper can be used as the basis for any policy decisions, they undergo rigorous review by the scientific community, industry, public interest groups,the general public, and the Clean Air Scientific Advisory Committee (CASAC).

Status of the Current Review
(as of December 2004)

EPA's Office of Research & Development issued a final PM Air Quality Criteria Document in October 2004. The document summarizes the state of current science about the effects of particle pollution.

EPA's Office of Air Quality Planning and Standards issued its first draft staff paper in August 2003. The draft:

  • notes that the latest scientific, health and technical information does not support relaxing EPA's current standards for fine particles;

  • offers preliminary staff recommendations that the Administrator consider revising both the annual and 24-hour PM2.5 standards to provide additional health protection; and

  • offers preliminary staff recommendations that the Adminstrator consider adding PM10-2.5 standards to protect against the effects of inhalable coarse particles.

EPA expects to issue a second draft staff paper and risk assessment in early 2005.

Before the final staff paper is used as the basis for any policy decisions, it will be reviewed by the scientific community, industry, public interest groups, the general public and CASAC. The final staff paper will include recommended options for the EPA Administrator to consider in deciding whether the PM standards should be changed.

EPA will propose a rule based on the review of the particle pollution standards by the end of 2005.

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