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The United States Environmental Protection Agency (“EPA”) in a May 15th Federal Register Notice announced the availability of two documents titled:

• Risk and Exposure Assessment for the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides (REA)
• Policy Assessment for the Review of the Primary National Ambient Air Quality Standard for Sulfur Oxides (PA)

See 83 Fed. Reg. No. 22479.

Sulfur Dioxide (SO₂) is one of the six air pollutants currently designated as a Clean Air Act criteria air pollutant. As a result, a National Ambient Air Quality Standard (“NAAQS”) was previously established for SO₂. Section 109 of the Clean Air Act requires that EPA promulgate “primary” and “secondary” NAAQS for the criteria pollutants identified under Section 108. EPA is periodically required to determine whether the standard should be adjusted based on additional scientific research, etc.

EPA states that the current periodic review of the air quality criteria and primary NAAQS for SO₂ began in 2013. The agency further states that the REA and PA build upon information presented in the ISA. The ISA refers to the Integrated Science Assessment for Sulfur Oxide’s – Health Criteria document that was completed in December 2017.

The final REA and PA are available at https://www.epa.gov/naaqs/sulfur-dioxide-so2-primary-air-quality-standards

A copy of the Federal Register Notice can be downloaded here.