air quality; causation; state boundaries

SB 1128 requires Arizona's air quality agency to consider emissions from other U.S. states and solar radiation effects when updating air quality plans, while explicitly excluding emissions originating outside the United States. It also authorizes Arizona's attorney general to sue the EPA if the agency refuses to approve plans demonstrating Arizona would meet ozone standards without foreign emissions. The bill is based on Arizona's claim that over 80% of ozone pollution in the Maricopa nonattainment area (Phoenix metro) comes from outside U.S. borders. This changes how Arizona factors external pollution into its air quality strategy and provides a legal path to challenge the EPA's interpretation of federal law.