Jump to main content or area navigation.

Contact Us

Air Quality: EPA's Integrated Science Assessments (ISAs)

Air Quality Criteria for Oxides of Nitrogen (External Review Draft, 1991)

Archive disclaimer
Archived files are provided for reference purposes only. The file was current when produced, but is no longer maintained and may now be outdated. Persons with disabilities having difficulty accessing archived files may contact the NCEA Webmaster for assistance. Please visit http://epa.gov/ncea to access current information.

Report Information

The revised air quality criteria document for oxides of nitrogen (NOx) reviews and evaluates the scientific information on the health and welfare effects associated with exposure to concentrations of NO2 found in ambient air. Although the document is not intended to be an exhaustive literature review, it is intended to cover all the pertinent literature through early 1991. The references cited in this document are, therefore, reflective of the current state of knowledge of those issues relevant to the subsequent review of the National Ambient Air Quality Standards (NAAQS) for NO2, currently set at 0.053 ppm (100 ug/m3), as an annual average. Gaps in knowledge are identified. Although emphasis is placed on the presentation of data on health and welfare effects, other scientific data are presented and evaluated in order to provide a better understanding of the properties and principles of formation, sources and emissions, atmospheric transport and transformation, measurement methods, ambient air concentrations, effects on crops and natural vegetation, effects on the terrestrial and aquatic ecosystems, effects on visibility, effects on materials, and health effects. Health effects include information derived from experimental toxicological studies of animals, epidemiological studies, and human clinical studies.

Jump to Table of Contents document
Mary Ross
  • by phone at:   919-541-5170
  • by fax at:   919-541-0237
  • by email at:  ross.mary@epa.gov

Additional Information

This draft document has been superseded by the final document: Air Quality Criteria for Oxides of Nitrogen, EPA 600/8-91-049aF


U.S. EPA. Air Quality Criteria for Oxides of Nitrogen (External Review Draft, 1991). U.S. Environmental Protection Agency, Washington, D.C., EPA/600/8-91/049aA (NTIS PB92176361), 1991.


This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

Jump to main content.