Area Designations for the Federal PM 2.5 Standard
This page last reviewed November 7, 2012
On December 18, 2006, the United States Environment Protection Agency (U.S. EPA) strengthened the 24-hour PM2.5 standard from 65 ug/m3 to 35 ug/m3. Per Clean Air Act requirements, ARB transmitted our nonattainment area recommendations to the U.S. EPA on December 17, 2007. These nonattainment area recommendations were based on 2004-2006 PM2.5 air quality monitoring data. ARB transmitted additional analysis in support of our earlier recommendations on October 15, 2008. U.S. EPA responded to our recommendations and posted these on their website.
In late 2009, U.S. EPA issued a final Federal Register notice designating areas as "nonattainment" and "unclassifiable/attainment" for the 24-hour national air quality standards for fine particulate matter (PM2.5), with additional designations and clarifications following in 2011. Further detailed information on the 2006 24-hour fine particulate (PM2.5) standard and the regulatory process can be found on the U.S. EPA website.
Below you will find links to meeting notices, staff reports, and transmitted documents, as well as the final Federal Register Notices issued by U.S. EPA.
2011 U.S. EPA Additional Air Quality Designations:
2009 U.S. EPA Final Designations:
2008 Additional Analysis to Support ARB Recommendations:
2008 U.S. EPA Response to ARB Recommendations: