William Yeatman of the Competitive Enterprise Institute notes that:
“Regional Haze is an aesthetic regulation pursuant to the Clean Air Act. Its purpose is to improve visibility at federal National Parks and Wilderness Areas. It is the only aesthetic regulation in the Clean Air Act. This point bears repeating: Unlike every other regulation established by the Clean Air Act, Regional Haze has nothing to do with public health.
“Another hallmark of the Regional Haze regulation is State primacy. Whereas EPA is the lead decision-maker when it comes to setting public health standards pursuant to the Clean Air Act, the Congress intended for the States to render determinations on Regional Haze.
“After countless hours of deliberation by State officials and significant public participation, Arizona submitted a Regional Haze implementation plan to the EPA in February 2011. Despite the Congress’s intention that States take the lead on Regional Haze decision-making, EPA Region 9 in mid-July disapproved Arizona’s submission, and proposed a federal implementation plan in its stead.”