Particulate Matter

The Issue
Particulate matter (PM) is a complex mixture of extremely small particles and liquid droplets in the air. Particulate matter causes concern because it is associated with serious health effects such as aggravated asthma, difficulty breathing, chronic bronchitis, decreased lung function, and premature death. PM contributes to haze and can harm the environment by changing the natural nutrient and chemical balance of the soil.

EPA Action
EPA scientists are conducting research to better understand which attributes of particulate matter cause ill health effects, who may be most susceptible to these effects, how particles form in the atmosphere, and what the contributions are from various sources in different regions of the country.

EPA's National Center for Environmental Assessment periodically evaluates the latest information concerning the public health and welfare effects of particulate matter and published the Air Quality Criteria Document for Particulate Matter. This final document provides the scientific basis for the establishment of national air quality standards.

Related Links

• Basic information about particulate matter
• Particulate matter research at EPA
• Particulate matter regulations
• Clean Air Act

History

Oct 2004	Air Quality Criteria for Particular Matter(Final), published
Sep 2004	CASAC reviews Chapter 9 via a publicly accessible teleconference
Aug 2004	Revised Chapter 9 released for CASAC and public review
Jul 2004	CASAC meets to review Chapters 7, 8, and 9
Jun 2004	Further revised drafts of Chapters 7, 8, and 9 released for CASAC and public review
Dec 2003	Revised drafts of Chapters 7 and 8 released for CASAC and public review
Aug 2003	CASAC meets to review Fourth Draft; closure reached on Chapters 1,2,3,4,5, and 6, with only relatively minor final revisions to be made
Jun 2003	Fourth External Review Draft released for CASAC and public review
Jul 2002	CASAC meets to review Third Draft
May 2002	Third External Review Draft released for CASAC and public review
Jul 2001	CASAC meets to review Second Draft
Apr 2001	Second External Review Draft released for CASAC and public review
Dec 1999	CASAC meets to review First Draft
Oct 1999	First External Review Draft released for Clean Air Scientific Advisory Committee (CASAC) and public review
Oct 1997	Plans for the review of the NAAQS for PM announced in the Federal Register

Best Resources

U.S. EPA. Air Quality Criteria for Particulate Matter (October 2004). U.S. Environmental Protection Agency, Washington, DC, EPA 600/P-99/002aF-bF, 2004.

U.S. EPA. Air Quality Criteria for Particulate Matter (External Review Drafts)..

U.S. EPA. Provisional Assessment of Recent Studies on Particulate Matter. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-06/063, 2006.

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