EPA has released the final “Integrated Science Assessment for Oxides of Nitrogen -Health Criteria.”  This is EPA’s latest evaluation of the scientific literature on the potential adverse human health effects resulting from exposures to oxides of nitrogen, particularly nitrogen dioxide or NO2.There are significant new health data, particularly epidemiological studies, since the last scientific review document released in 1993.

Oxides of nitrogen is one of the six criteria pollutants for which EPA is required to issue air quality criteria under the Clean Air Act (CAA). EPA set a national ambient air quality standard (NAAQS) for nitrogen dioxide (NO2), an indicator for gaseous nitrogen oxides, at an annual average of 0.053 parts per million (ppm).

The CAA also requires EPA to periodically update the scientific basis for these standards by preparing an Integrated Science Assessment.The assessment released today will be critical in the review of the NAAQS for NO2.The document went through independent, external peer review by the Clean Air Scientific Advisory Committee, and opportunities were also provided for public review and comment.