"Americans could breathe more smog and toxic chemicals on summer days if regulators fail to get a handle on companies that use diesel-burning generators as a last line of defense against power outages, a coalition of state officials from the Northeast says in a new report."

"CHEYENNE, Wyo. -- A federal judge has dismissed a legal challenge from environmental groups that sought to block federal coal leases in Wyoming's Powder River Basin on the grounds that burning the coal would contribute to global warming."

"U.S. Steel violated the Clean Air Act numerous times — in one case, more than 15,000 times — at its Gary Works facility and two other plants in Michigan and Illinois, according to a lawsuit filed by the federal government Wednesday in the U.S. District Court in Hammond."

"A byproduct of the ongoing heat wave, increased smog, may ultimately bring more and longer-lasting annoyance than the heat itself. The heat wave will eventually break, but Wichita’s smog reports probably already have been damaged to the extent of triggering some mandatory -- and potentially costly and inconvenient -- pollution controls like those in other big cities."

"Athletes completing their final pre-Olympics training, and members of the public gathering in London for the final stages of the Olympic torchrelay, have been warned of high levels of pollution in the UK capital on Thursday, ahead of the opening ceremony on Friday night."

"GALVESTON - With the world focused on a BP rig explosion in the spring of 2010 that caused the worst oil spill in U.S. history, a massive release of pollutants from the company's Texas City refinery went largely unnoticed."

"Strong summer thunderstorms that pump water high into the upper atmosphere pose a threat to the protective ozone layer over the United States, researchers said on Thursday, drawing one of the first links between climate change and ozone loss over populated areas."

"BILLINGS, Mont. -- Environmentalists filed notice Wednesday that they plan to sue the six companies that co-own eastern Montana's Colstrip power plant over alleged pollution violations."

"Cutting soot and other air pollutants could help 'buy time' in the fight against climate change, a senior U.S. official said on Tuesday as seven nations joined a Washington-led plan."