Draft Staff Report: Review of the Ambient Air Quality Standard (AAQS)
for Nitrogen Dioxide (NO2)

This page reviewed November 25, 2009.

The staff of the Air Resources Board (ARB) in consultation with the Office of Environmental Health Hazard Assessment (OEHHA) have reviewed the California Ambient Air Quality Standard (AAQS) for nitrogen dioxide (NO2). Based on the results of the staff review, the ARB staff recommended to the Board that the existing NO2 standard be as follows:


Lower the existing 1-hour-average standard for nitrogen dioxide to 0.18 ppm, not to be exceeded.


Establish a new annual average standard for nitrogen dioxide at 0.030 ppm, not to be exceeded.


Retain the current chemiluminescence monitoring method.
Staff's review of the scientific literature on NO2 includes information on the human health effects, welfare effects (animal, ecological, environmental), public exposure, and atmospheric chemistry of NO2. The findings of that review are contained in a Staff Report and Technical Support Document, which are available below.

First Draft of the NO2 Standard Staff Report and Technical Review Document

Draft Staff Report Complete Draft Staff Report (890KB - PDF)
Draft Technical Support Document Complete Draft Technical Support Document (3,198KB - PDF)

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.

Nitrogen Dioxide Review Schedule

Ambient Air Quality Standards