"A conservation group found 36 U.S. national parks had moderate or worse levels of ozone pollution in a report card released on Tuesday, with four parks in California receiving the worst grades for health effects."

"A U.S. appeals court on Tuesday mostly upheld a major federal environmental regulation requiring some states to limit pollution that contributes to unhealthy air in neighboring states."

"HAZARD, Ky. — Even after years of talk about a “war on coal,” Senate Majority Leader Mitch McConnell startled some of his constituents in March when he urged open rebellion against a White House proposal for cutting pollution from coal-fired power plants."

"The U.S. Environmental Protection Agency proposed a program for oil and gas companies to make voluntary pledges to cut and track emissions of methane, one component of its wider strategy to target the potent greenhouse gas and combat climate change, the agency said Thursday."

"The D.C. Circuit Court of Appeals has upheld an Environmental Protection Agency (EPA) rule on emissions of certain toxic air pollutants at manufacturing plants."

"Mercury levels in bluefish caught off the U.S. Atlantic coast dropped more than 40 percent over the past four decades thanks to federal restrictions on coal emissions, according to a new study."

"Air pollution in the Twin Cities contributes to about 2,000 premature deaths every year, and sends 1,000 people to the hospital for asthma, lung and heart disease treatments."

"Environmental Defense Fund-backed studies of 30,000 Barnett Shale wells shows the EPA has vastly underestimated emissions."

"The Canadian military has been called in to help fight wildfires in the Western province of Saskatchewan, where 112 active fires have forced the evacuation of more than 13,000 people and threatened several remote towns on Monday."

"The Obama administration moved Thursday to restrict the use of hydrofluorocarbons (HFCs), the most potent greenhouse gases emitted by human activity."