Review of the Ambient Air Quality Standard (AAQS)
for Nitrogen Dioxide (NO₂)

What's New! (Click Here)

On Tuesday, February 19, 2008, the Office of Administrative Law approved amendments to the regulations for the State Ambient Air Quality Standard for nitrogen dioxide (NO₂).  The new standards became effective on March 20, 2008.

The Air Resources Board approved staff recommendations to amend the NO₂ standard on February 22, 2007 [click here for the press release]. The recommendations were based on a review of the scientific literature on the health effects of NO₂ that was conducted by staff from the Air Resources Board and the Office of Environmental Health Hazard Assessment.  The review and final recommendations for the NO₂ standard were released in a final staff report on January 5, 2007. In this report, staff recommended lowering the existing 1-hour-average standard for NO₂ of 0.25 ppm to 0.18 ppm, not to be exceeded, and established a new annual-average standard of 0.030 ppm, not to be exceeded. The Staff Report and Technical Support Document are available at this link.

The staff recommendations and supporting information were peer-reviewed by the Air Quality Advisory Committee. Members of this committee, appointed by the Office of the President of the University of California, are experts in health sciences, exposure assessment, monitoring methods, and atmospheric sciences. All meeting and workshop notices are posted below.

For more info on review of the NO₂ ambient air quality standard, please contact
Dr. Norman Kado at (916) 323-1500 or email at nkado@arb.ca.gov.