The Ninth Circuit Court of Appeals has upheld EPA’s approval of interim motor vehicle emissions budgets included in the South Coast Air Quality Management District (SCAQMD) state implementation plan (SIP). NRDC v. EPA, No. 08-72288 (9th Cir. 3/30/11). Challenging the agency’s approval, NRDC argued that the “emissions budgets” and the attainment demonstration plan failed to consider higher concentrations of harmful particulates along certain highways in the Los Angeles air basin. NRDC also contended that EPA failed to consider elevated levels of fine particulates (PM-2.5) as part of the clean air planning process.

EPA countered that its finding was consistent with agency rules for making interim determinations on baseline budgets for transportation conformity purposes. The court agreed with EPA, finding that the agency’s reading of its own regulations, which do not require an approvable attainment demonstration, was reasonable. The court therefore denied the petition for review.