# PM Standards Revision **- 2006**  Background What do the new standards mean for your area? Maps Timeline More information

**Background** Particle pollution, also called particulate matter or PM, is a complex mixture of extremely small particles and liquid droplets in the air. When breathed in, these particles can reach the deepest regions of the lungs. Exposure to particle pollution is linked to a variety of significant health problems, ranging from aggravated asthma to premature death in people with heart and lung disease. Particle pollution also is the main cause of visibility impairment in the nation’s cities and national parks. To protect public health and welfare, EPA issues National Ambient Air Quality Standards (NAAQS) for six criteria pollutants , p articulate matter is one of these. EPA first issued standards for particulate matter in 1971; and revised the standards in 1987 and 1997. In September 2006, the Agency revised the 1997 standards. The revised 2006 standards address two categories of particle pollution: fine particles (PM 2.5 ), which are 2.5 micrometers in diameter and smaller; and inhalable coarse particles (PM 10 ) which are smaller than 10 micrometers and larger than 2.5 micrometers. The 2006 standards tighten the 24 - hour fine particle standard from 65 micrograms per cubic meter (μg/m 3 ) to 35 μg/m 3 , and retain the current annual fine particle standard at 15 μg/m 3

. EPA has decided to retain the existing 24 - hour PM 10 standard of 150 μg/m 3 . Due to a lack of evidence linking health problems to long -term exposure to coarse particle pollution, the Agency has revoked the annual PM 10 standard. The Agency selected the levels for the final standards after reviewing thousands of peer- reviewed scientific studies about the effects of particle pollutio n on public health and welfare. External scientific advisors and the public examined EPA's science and policy review documents. The Agency also carefully considered public comments on the proposed standards. EPA held three public hearings and received over 120,000 written comments. While EPA provisionally assessed new, peer- reviewed studies about particulate matter and health (including some studies received during the comment period), these studies were not the basis for thefinal decision. EPA will consid er those studies during the next review of the PM standards. Learn more

about the process of reviewing air quality standards .

**What do the New Standards Mean for Your Area?** In 2004, several areas in the United States were designated as not meeting the 1997 air quality standards for fine particulate matter (PM 2.5 ). See if your area was designated as not meeting the 1997 standards . In 2006, EPA strengthened the air quality standards for particle pollution. The Agency expects designations based on 2007 - 2009 air quality data to take effect in 2010.

**Maps** Graph and Maps (10/25/06) (PDF, 10 pp, 1.2 MB)

**Timeline Milestone**  **1997 PM 2.5**  **Primary NAAQS 2006 PM**  **2.5 Primary NAAQS**  **Promulgation of Standard** July 1997 Sep. 2006 **Effective Date of Standard** Sep. 1997 Dec. 18, 2006 **State Recomme ndations to**  **EPA** Feb. 2004 (based on 2001 - 2003 monitoring data) Dec. 18, 2007 (based on 2004 - 2006 monitoring data) **Final Designations Signature** Dec. 2004 No later than Dec. 18, 2008* **Effective Date of Designations**  April 2005 Typically no later than 90 da ys after publication in the Federal Register **SIPs Due** April 2008 3 years after effective date of designations **Attainment Date** April 2010 (based on 2007 - 2009 monitoring data) No later than 5 years after effective date of designations **Attainment Date w ith**  **Extension** Up to April 2015 No later than 10 years from effective date of designations * In the event the Administrator has insufficient information to promulgate the designations by December 18, 2008, the date of final designations may be extended u p to one year, but no later than December 18, 2009.**More Information**