Review of the Ambient Air Quality Standard for Ozone

This page reviewed September 14, 2017

Ozone, a major component of smog, is a gas capable of damaging the lungs and respiratory tract. ARB staff reviewed the scientific literature and recommended revisions to the ozone standard based on that review. On April 17, 2006, the Office of Administrative Law approved amendments to the regulations for the State Ambient Air Quality Standard for Ozone. The revised standard became effective on May 17, 2006.
The Air Resources Board approved staff recommendations to amend the ozone standard on April 28, 2005 [see the press release]. The recommendations were based on a review of the scientific literature on the health effects of ozone that was conducted by staff from the Air Resources Board (ARB) and the Office of Environmental Health Hazard Assessment (OEHHA). The review and final recommendations for the ozone standard were released as a final staff report for public comment on March 11, 2005. The staff report recommended retaining the existing 1-hour ozone standard of 0.09 ppm, and establishing a new 8-hour standard of 0.070 ppm.
At the April 28 hearing, staff presented a modified health impacts analysis, using a different methodology than the analysis presented in the staff report released on March 11, 2005. In response, the Board requested that staff modify the staff report to incorporate the health impacts analysis modifications presented at the Board hearing, and to make that text available to the public. [Click here for a summary of the Board hearing]. The modified staff report, released on October 27, 2005, does not replace the March 11, 2005 Staff Report / Initial Statement of Reasons. Instead, it presents staff's current methodology for calculating health impacts of ozone exposure, and recalculated health impacts results.
The staff recommendations and their bases were peer-reviewed by the Air Quality Advisory Committee. Members of this committee are appointed by the Office of the President of the University of California, and are experts in health sciences, exposure assessment, monitoring methods, and atmospheric sciences. All meeting and workshop notices are posted below.
This action follows a preliminary evaluation of all health-based ambient air quality standards in December 2000 to determine their adequacy to protect public health, particularly that of infants and children. Staffs of the ARB and OEHHA concluded in the December 2000 report that significant harmful health effects may occur among both children and adults when outdoor ozone concentrations are at or near the current State standards. The health-based standards evaluation was a requirement of The Children's Environmental Health Protection Act (Senate Bill 25, Escutia, 1999).
We are using the ARB's air quality standards list serve to send out notices on the status of the ozone standard review. You may sign up to receive list serve emails.

The Milestones of the Ozone Standard Review are listed below:



May 17, 2006

Ozone Standards Effective

October 27, 2005

Revised Staff Report (October 27, 2005)

October 27, 2005

15-Day Public Notice

April 28, 2005

Air Resources Board Approves Staff Recommendations

April 11, 2005
April 12, 2005

Public Workshops to discuss the Staff Report and Recommendations to Amend the Ambient Air Quality Standards for Ozone


March 11, 2005

Staff Report and Recommendations to Amend the Ambient Air Quality Standards for Ozone


January 11-12, 2005

Air Quality Advisory Committee (AQAC) Meeting
  AQAC Meeting Summary Information - Findings, Presentations and transcripts.
  The Air Quality Advisory Committee, appointed by the University of California, is a scientific peer review committee that met to independently evaluate the scientific basis of draft recommendations for revising the California ambient air quality standard for ozone.

December 13, 2004

Public Comments on the Draft Staff Report and Summary of Staff Comments
and Responses

August 24, 2004

Public Release of Draft Health Benefits Chapter
  The objective of this draft chapter is to quantify the potential reductions in adverse health effects from reduced exposures to ozone from attaining the ozone standards recommended in the draft staff report. Although these "Health Benefits" are not the basis for the staff's draft recommendations for the ozone standard, they illustrate the benefits from attainment of the standard. It will become Chapter 10 in the draft staff report.
  The period for public comment ended on September 24, 2004.

July 14 - 16, 2004
August 25, 2004

Public Workshops to Discuss the Draft Staff Report

June 21, 2004

Public Release of Draft Staff Report
  Extended Comment Period ended on September 1, 2004

October 10, 2002

Request to the public for recently published or in press articles for the ozone review.
    Please click here for the request letter.

For more information on review of the ozone ambient air quality standard, please contact
Dr. Deborah Drechsler at (916) 323-1526.