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Sulfur Dioxide (SO2) Air Quality Attainment/Nonattainment Designations

All National Ambient Air Quality Standards (NAAQS) undergo periodic review and may be revised to reflect the latest health, environmental and technological advances. When a new standard is promulgated or an existing standard is revised, the first step in implementation is to determine which areas are, or are not, violating the NAAQS or are contributing to a violation of the NAAQS. During the “designation process,” states have the opportunity to submit data and recommendations, which U.S. EPA reviews and considers before issuing final designations. Following are documents relating to Indiana’s air quality designation process for the sulfur dioxide NAAQS.

SO2 Designation Documents

Rounds 3 and 4 Nonattainment Designations

Round 2 Nonattainment Designations

Round 1 Nonattainment Designations

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