The D.C. Circuit upheld EPA’s decision to defer adopting new secondary NAAQS for oxides of sulfur (SOx) and nitrogen (NOx) pending further scientific study. Citing doubts about the accuracy of its…

The D.C. Circuit denied industry groups' petition for review challenging EPA's 2013 primary NAAQS for fine particulate matter. In the final rule, EPA lowered the level of the particulate…

 The primary standards for carbon monoxide have remained the same since 1971. There has not been a secondary standard for carbon monoxide since EPA revoked a secondary standard in 1985.…

The Michigan Court of Appeals, in an unpublished opinion, upheld the state environmental agency's decision to issue two permits authorizing modifications at a coal-fired power plant. The…

A district court denied industry groups' motion to intervene in a CAA citizen suit concerning EPA's alleged failure to review the ozone NAAQS in a timely manner. The underlying lawsuit…

The D.C. Circuit remanded for reconsideration EPA's revisions to the secondary, welfare-based NAAQS for ozone, but denied petitions challenging revisions to the primary, health-based ozone…

A district court dismissed a city's lawsuit against California state and local air districts challenging fees it must pay to mitigate wind-blown dust from a dry lake bed that exceed state and…

The D.C. Circuit ordered EPA to repromulgate two final rules it issued under the CAA concerning the implementation of the NAAQS for fine particulate matter (PM). Environmental groups challenged…

The D.C. Circuit dismissed petitions challenging EPA's primary NAAQS for sulfur dioxide (SO2). The petitioners—several states, state regulatory agencies, corporations, and industrial…

The D.C. Circuit denied petitions challenging EPA's one-hour primary NAAQS for nitrogen dioxide (NOx). The new one-hour primary NAAQS requires that “the three-year average of the annual 98th…