This Technical Support Document (TSD) demonstrates EPA’s analysis to quantify the SO₂ emissions that significantly contribute to nonattainment or interfere with maintenance of the National Ambient Air Quality Standards (NAAQS) in downwind states for the Revisions to the Transport Rule.

• Significant Contribution Assessment TSD (PDF)(28 pp, 565 K, October 2011)
  Technical Support Document (TSD) for the Revisions to the Transport Rule