2010 1-Hour SO2 NAAQS Interstate Transport

Current understanding

To be populated as evidence accumulates.

2026-10-08 — Air Plan Approval; Oklahoma; Interstate Transport Requirements for the 2010 SO2 NAAQS: 2025 — EPA final rule approved Oklahoma’s good-neighbor SIP for the 2010 1-hour SO2 NAAQS, concluding the state’s emissions do not significantly affect downwind attainment or maintenance; adds Oklahoma to the set of states (including Iowa) whose transport obligations EPA has found satisfied without additional controls. (novelty: 2)
2026-09-09 — Air Plan Approval; New York; Interstate Transport Requirements for the 2010 SO2 NAAQS: EPA finalized approval of New York’s Good Neighbor SIP for the 2010 1-hour SO2 NAAQS, finding the state’s SO2 emissions will not significantly contribute to nonattainment or interfere with maintenance of the standard in downwind states. (novelty: 2)
2026-08-27 — Air Plan Approval; Mississippi; 2010 1-Hour SO2 NAAQS Transport Infrastructure: EPA proposed approval (2026) of Mississippi’s Good Neighbor SIP submission, finding the state’s SO2 emissions will not significantly contribute to nonattainment or interfere with maintenance of the 2010 1-hour SO2 NAAQS in other states. (novelty: 2)