Environmental Assessment 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=201485

Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Ecological 

Criteria (Final Report) 

EPA has released the final report, Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur - Ecological Criteria. This final 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.

Expand Accordion

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 AQCDs for oxides of nitrogen and sulfur were released in 1993 and 1982, respectively. 

This ISA was prepared as part of the joint review of the secondary or welfare-based NAAQS for oxides of nitrogen and sulfur. 

The 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 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. 

This is the final report. 

For technical questions only, contact Tara Greaver. 

All other questions should be directed to the contact us link listed below. 

Notice

[12/22] On December 22, 2008, an updated version of the ISA was posted to this site. In this updated version, the Executive Summary has 

been revised stylistically and graphics resolution has been adjusted in the ISA. No substantive changes have been made to the document. In 

addition, the Executive Summary and individual ISA and Annex chapters have been posted as separate files. 

The Integrated Science Assessment for Oxides of Nitrogen and Sulfur - Ecological Criteria and the Annexes were announced in a December

12, 2008 Federal Register Notice. 

Report Information

Background

History/Chronology

1982 EPA released the document Air Quality Criteria for Oxides of Nitrogen and the Air Quality Criteria for Particulate Matter and Sulfur Oxides.

Aug 1993 EPA released the final document Air Quality Criteria for Oxides of Nitrogen.

Dec 2007 EPA 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.

Aug 2008 EPA 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.

Dec 2008 EPA releases the final report of the Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur – Ecological Criteria document.

Next Steps

Additional Information

Citation

Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Ecological Criter... Page 1 of 2

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=201485 7/5/2011
U.S. EPA. Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Ecological Criteria (Final Report). U.S. Environmental Protection Agency, Washington, 

DC, EPA/600/R-08/082F, 2008. 

 Integrated Science Assessment for Oxides of Nitrogen and Sulfur – Ecological Criteria (Final Report) (PDF) (898 pp, 42 MB, about PDF) 

 ISA NOx-SOx Final: Front Matter (PDF) (37 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Executive Summary (PDF) (13 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Chapter 1. Introduction (PDF) (8 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Chapter 2. Source to Deposition (PDF) (191 pp, 17 MB, about PDF) 

 ISA NOx-SOx Final: Chapter 3. Ecological and Other Welfare Effects (PDF) (206 pp, 9 MB, about PDF) 

 ISA NOx-SOx Final: Chapter 4. Summary and Conclusions (PDF) (44 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Annex A. Ecosystem Monitoring and Models (PDF) (51 pp, 5 MB, about PDF) 

 ISA NOx-SOx Final: Annex B. Acidification Effects (PDF) (121 pp, 7 MB, about PDF) 

 ISA NOx-SOx Final: Annex C. Nutrient Enrichment Effects from Nitrogen (PDF) (45 pp, 5 MB, about PDF) 

 ISA NOx-SOx Final: Annex D. Critical Loads (PDF) (22 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Annex E. Effects of NO Y, NH X, and SOx on Structures and Materials (PDF) (16 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Annex F. Valuation of the Environmental Effects of N and S (Non-Materials) (PDF) (40 pp, 4 MB, about PDF) 

 ISA NOx-SOx Final: Glossary & References (PDF) (104 pp, 13 MB, about PDF) 

Downloads

Integrated Science Assessment (ISA) for Oxides of Nitrogen and Sulfur Ecological Criter... Page 2 of 2

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=201485 7/5/2011