Regional Haze (Visibility Protection)

Current understanding

To be populated as evidence accumulates.

2026-09-09 — Air Plan Approval; Reconsideration and Repeal of Air Plan Partial Approval and Partial Disapproval of North Dakota’s Regional Haze State Implementation Plan for the Second Implementation Period: cross-connection with regional-haze-sip: Both address the Regional Haze Program under the Clean Air Act; the state SIP page tracks state-specific second-period plan actions while the visibility-protection page covers the underlying federal program framework. (novelty: 2)
2026-08-27 — Air Plan Approval; Arkansas; Regional Haze State Implementation Plan for the Second Implementation Period: EPA final rule (final-rule) approves Arkansas’s Regional Haze SIP for the second implementation period (2018–2028), covering reasonable-progress determinations for man-made visibility impairment at Class I areas. (novelty: 2)