Integrated Science Assessment (ISA) for Sulfur Oxides – Health Criteria (Final Report, Dec 2017)

The Integrated Science Assessment for Sulfur Oxides – Health Criteria is a concise synthesis and evaluation of the most policy-relevant science, and has been prepared as part of the review of the primary (health-based) National Ambient Air Quality Standards (NAAQS) for Sulfur Oxides (SOx)under the Clean Air Act. The SOx ISA, in conjunction with additional technical and policy assessments, provides the policy relevant scientific information necessary to conduct a review of the current primary and secondary air quality standards for Ozone sufficiently protects public health. The SOx ISA reviews information on atmospheric science, exposure, dosimetry, mode of action, and health effects related to sulfur oxides and sulfur dioxide (SO2), including evidence from controlled human exposure, epidemiologic, and toxicological studies.

Sulfur oxides are one of six principal (or criteria) pollutants for which EPA has established national ambient air quality standards (NAAQS). For sulfur oxides, the NAAQS are specified in terms of sulfur dioxide (SO2). The Clean Air Act requires EPA to periodically review the scientific basis for these standards by preparing an Integrated Science Assessment. These reviews play a significant role in EPA’s commitment to ensuring a clean and healthy environment for the public.

The ISA is part of the Agency’s periodic review of the primary (health-based) NAAQS for sulfur oxides. Overall, findings from recent studies strengthen the conclusions from the previous NAAQS review, which was completed in 2010. Results from recent studies strengthen the body of evidence indicating that short-term exposure to SO2 can cause respiratory effects, in particular, effects related to asthma exacerbation. There is more uncertainty regarding the potential for SO2 effects outside the respiratory system.

Impact/Purpose

The Clean Air Act mandates that EPA periodically review the national ambient air quality standards (NAAQS) for SOx, as measured by SO2. The purpose of this ISA is to provide a comprehensive review, synthesis, and evaluation of the most policy-relevant science to serve as the scientific foundation for the current primary (health-based) NAAQS for sulfur oxides.

Citation

U.S. EPA. Integrated Science Assessment (ISA) for Sulfur Oxides – Health Criteria (Final Report, Dec 2017). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-17/451, 2017.

History/Chronology

DateDescription
Sep 2008EPA released the Final Report of the Integrated Science Assessment for Sulfur Oxides (SOx) - Health Criteria (EPA/600/R-08/047F). [Federal Register Notice Sep 12, 2008]
May 2013EPA initiated the current review of the air quality criteria for SOX and the primary SO2 NAAQS, and also issued a call for information. [Federal Register Notice May 10, 2013]
Jun 2013EPA held a workshop entitled "Workshop to Discuss Policy-Relevant Science to Inform EPA's Integrated Plan for Review of the National Ambient Air Quality Standards for Sulfur Oxides" co-organized by EPA/ORD/NCEA and the EPA/OAQPS Staff to help with the development of future products on this subject matter. The workshop was held June 12-13, 2013, in Research Triangle Park, North Carolina. [Federal Register Notice May 10, 2013]
Mar 2014EPA released the Integrated Review Plan for the Primary National Ambient Air Quality Standard for Sulfur Dioxide – External Review Draft. [Federal Register Notice Mar 12, 2014]
Apr-Jul 2014CASAC held multiple public teleconferences to discuss the draft Integrated Review Plan. [Federal Register Notice Mar 25, 2014, Federal Register Notice May 27, 2014, Federal Register Notice Jun 18, 2014]
Jun 2014EPA held a public workshop to review initial draft materials to inform the development of the draft Integrated Science Assessment for Sulfur Oxides – Health Criteria.[Federal Register Notice Jun 12, 2014]
Oct 2014EPA released the final ‘Integrated Review Plan for the Primary National Ambient Air Quality Standard for Sulfur Dioxide' (EPA-452/R-14-007). [Federal Register Notice Nov 10, 2014]
Nov 2015EPA released the external review draft for public and independent peer review. [Federal register Notice Nov 24, 2015]
Dec 2015EPA announced a SAB advisory meeting to discuss the draft report in a December 21, 2015 Federal Register Notice. On December 24, 2015, EPA extended the public comment period adding an additional 30-days. The comment period is now February 24, 2016. [Federal Register Notice Dec 24, 2015]
Dec 2016EPA released the second external review draft for public and independent peer review. [Federal Register Notice Dec 9, 2016]
May 2017EPA announced a SAB public teleconference call on June 20, 2017 to discuss the second draft report. [Federal Register Notice May 23, 2017]
Dec 2017EPA released the final report. [Federal Register Notice Dec 13, 2017]