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

Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Environmental Criteria (Second External Review Draft)

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Report Information

EPA has announced that the Second External Review Draft of the Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur - Environmental Criteria has been made available for independent peer review and public review. This draft ISA document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA's decision on retaining or revising the current secondary standards for NO2 and SO2.

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Tara L. Greaver
  • by phone at:   919-541-2435
  • by email at:  greaver.tara@epa.gov

Background

Oxides of nitrogen and oxides of sulfur are two of six principal (or criteria) pollutants for which EPA has established national ambient air quality standards (NAAQS). The Clean Air Act requires EPA to periodically review the scientific basis for these standards by preparing an Integrated Science Assessment (ISA), formerly called an Air Quality Criteria Document (AQCD). The previous scientific review documents for oxides of nitrogen and sulfur were released in 1993 and 1982, respectively.

This draft ISA was prepared as part of the joint review of the secondary or welfare-based NAAQS for oxides of nitrogen and sulfur. The draft ISA evaluates and integrates the newly available environmental evidence, and contains the key information and judgments formerly found in the AQCD. A series of Annexes to the draft ISA provides more extensive and detailed summaries of the most pertinent scientific literature. This is EPA’s latest evaluation of the scientific literature on the potential adverse environmental effects resulting from exposures to oxides of nitrogen and sulfur. There are significant new data, particularly with regards to acidification and nitrogen enrichment, that strengthen the evidence for these effects since the last scientific review documents were released.

History/Chronology

1982EPA released the document Air Quality Criteria for Oxides of Nitrogen and the Air Quality Criteria for Particulate Matter and Sulfur Oxides.
Aug 1993EPA released the final document Air Quality Criteria for Oxides of Nitrogen.
Dec 2005EPA published a Call for Information on Oxides of Nitrogen in a December 9, 2005 Federal Register Notice.
May 2006EPA put out a call for related information in a May 15, 2006 Federal Register Notice to update the science assessment for sulfur oxides.
July 2007EPA hosted a workshop on the assessment of environmental and welfare effects science for the review of the secondary NAAQS for Oxides of Nitrogen and Sulfur.
Aug 2007EPA released the draft document, Integrated Science Assessment (ISA) for Oxides of Nitrogen – Health Criteria (Second External Review Draft).
Sep 2007EPA released the draft document, Integrated Science Assessment (ISA) for Sulfur Oxides - Health Criteria and the Annexes (Second External Review Draft).
Dec 2007EPA releases the Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Environmental Criteria (First External Review Draft) for an external peer review and public comment.
Feb 2008EPA releases the Annexes for the Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Environmental Criteria (First External Review Draft).
Aug 2008EPA releases the Second External Review Draft of the Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur – Environmental Criteria document for an external peer review and public comment.
Sep 2008EPA extended the deadline for public comment to October 10, 2008, for both of these documents.

Additional Information

Included for public review is the draft Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur – Environmental Criteria (Second External Review Draft). Comments on this document may be submitted and reviewed using the e-Government Regulations.gov Web site. From the site, select Environmental Protection Agency and the keyword EPA-HQ-OAR-2007-1145 (for the docket ID) to comment on this report. The deadline for comments is October 1, 2008.

Citation

U.S. EPA. Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Environmental Criteria (Second External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/082, 2008.

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