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National Ambient Air Quality Standards (NAAQS)

Sulfur Dioxide (SO2) Primary National Ambient Air Quality Standards

The Clean Air Act requires EPA to set national ambient air quality standards (NAAQS) for sulfur dioxide and five other pollutants considered harmful to public health and the environment (the other pollutants are ozone, particulate matter, nitrogen dioxide, carbon monoxide, and lead). The law also requires EPA to periodically review the standards to ensure that they provide adequate health and environmental protection, and to update those standards as necessary. Learn more about the NAAQS review process.

Contact: Dr. Michael Stewart

Documents from Current Review

  • Planning Documents
  • Integrated Science Assessments
  • Risk and Exposure Assessments
  • Policy Assessments
  • Other Technical Documents
  • CASAC Documents
  • Federal Register Notices
  • Response to Comments Document
  • Regulatory Impact Analysis
  • Litigation

Basic Information on SO2

Documents from Review Completed in 2010

Documents from Review Completed in 1996

Table of Current NAAQS

Table of Historical SO2 NAAQS

Air Quality Index


File Utilities

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