Previous Federal Ozone Activities - 2008 Standard

This page reviewed May 21, 2012




US EPA Finalizes Area Designations and Classifications for 2008 Federal 8-Hour Ozone Standard:

On April 30, 2012, U.S. EPA issued final area designations and classifications for the 2008 (0.075 ppm) 8-hour ozone standard. The designations include two new nonattainment areas -- Eastern San Luis Obispo County and the Tuscan Buttes area of Tehama County. The area designations and classifications will be effective July 20, 2012. 

If you have questions, please contact Gayle Sweigert or Marci Nystrom .

Initial Area Designation Recommendations:

U.S. EPA Submittal -- Initial ARB Recommended Area Designations for the 2008 Federal 8-Hour Ozone Standard:

On March 12, 2009, ARB submitted its area designation recommendations for the revised federal 8-hour ozone standard, based on ozone air quality data collected during 2006 through 2008. As initially recommended, there were 21 nonattainment areas, including all areas that were nonattainment for the federal 1997 8-hour ozone standard and 6 new or expanded areas. In addition to the nonattainment areas, ARB recommended 12 areas be designated as attainment and 5 areas be designated as unclassified.

NOTE:  The links below relate to the initial area designation recommendations. However, U.S. EPA made the final area designations and classifications based on more current data. If you have questions, please contact Gayle Sweigert or Marci Nystrom .



Potential 8-Hour Ozone Exceptional Events:

NOTE:  Although ARB submitted exceptional events documentation for Northern California ozone data impacted by the 2008 wildfires, U.S. EPA did not act on the submittal.  Furthermore, because final area designations for the 2008 federal ozone standard were based on more recent data, there was no reason to exclude the impacted data for designation or classification purposes.  

U.S. EPA guidance allows air quality data affected by exceptional events to be excluded from the regulatory process. During the summer of 2008, a number of large wildfires burned throughout Caifornia, and smoke from these fires impacted ozone concentrations. Per U.S. EPA rules, ARB submitted documentation for exceptional events that occurred during the 2008 calendar year by March 12, 2009. A link to the documentation package is provided, below. 

Exceptional Events Documentation for Shasta County:


Exceptional Events Documentation for Other Northern California Areas:





Comments and questions may be sent to:

Ms. Marci Nystrom
(916) 323-8543


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