Today, the U.S. Environmental Protection Agency (EPA) proposed a revision to the national air quality standard for ozone, a.k.a. smog. EPA is proposing to tighten the primary standard to a level somewhere between 0.060 and 0.070 ppm (parts per million), down from the current standard of 0.075 ppm set in 2008. Under the Clean Air Act, EPA must set the primary standard at a level protective of public health.

As the Washington Post reports today, EPA is temporarily delaying a decision to regulate coal ash, a toxic byproduct formed when smokestack scrubbers capture pollutants otherwise destined for the air. Today is the one-year anniversary of a major coal ash spill that sent a billion gallons of toxic goo cascading across hundreds of acres of land in eastern Tennessee.

Greenhouse gases are officially a threat to public health and the environment in the eyes of the federal government. Yesterday, the U.S. Environmental Protection Agency (EPA) finalized its endangerment finding for greenhouse gases. The finding will now compel the agency to regulate emissions under the Clean Air Act.

The Department of the Interior published today an advanced notice of proposed rulemaking that lays out options for mitigating the environmental impact of mountaintop mining. Specifically, the notice discusses a Bush administration rule finalized in December 2008 which allows mining operations to dump waste in or near rivers and streams.