Last week, the U.S. Court of Appeals for D.C. Circuit struck down rules promulgated by the Environmental Protection Agency to implement the national air quality standards for fine particulates in Natural Resources Defense Council v. EPA. (Story here.) One thing that’s notable about the decision is that the Court was reviewing a pair of rules promulgated in 2007 and 2008. It’s also notable is that this is yet one more decision in which the D.C. Circuit rejected a Bush Administration air pollution regulation. As I’ve noted before (see also here), the Bush Administration appeared to have a pretty poor record at defending its air pollution regulations in federal court. Time-and-again, the D.C. Circuit found, the EPA failed to comply with the Clean Air Act in issuing its rules. Some of the EPA rules at issue may have made good sense, from a policy perspective, but they were illegal nonetheless. This string of losses — combined with some of the Obama Administration’s failed efforts to replace the invalidated Bush-era rules — may indicate that portions of the Clean Air Act are outdated and in need of reform, but that does not excuse an agency’s failure to follow the law. Whatever the cause, the Bush EPA had a particuarly hard time complying with Clean Air Act.