"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."

"The Environmental Protection Agency announced on Friday afternoon that it would review its new standards for mercury, soot and other emissions for a handful of proposed new coal-burning power plants.

The review will delay the implementation of the regulation for the new plants for at least three months while experts determine whether the emissions limits may safely be relaxed.

"The White House recently modified an Environmental Protection Agency proposal to limit soot emissions, according to documents obtained by The Washington Post, inviting public comment on a slightly weaker standard than the agency had originally sought."

"A federal appeals court upheld a new Environmental Protection Agency rule to limit nitrogen dioxide emissions near major roadways, in a defeat for the oil industry, which said the rule went beyond what was necessary to protect public health."

"CALEXICO, CALIF. — As the relentless wind stirs up piles of dust and dirt and creates a gigantic funnel of haze in the vast, sweltering Imperial Valley, children like Marco Cisneros battle to breathe."

"Shell has asked the Environmental Protection Agency to loosen air pollution requirements for its Discoverer drill rig, which is planning to begin exploratory drilling operations off the North Slope of Alaska early next month."

"It's high season in the nation's national parks as millions of visitors come to see nature. If last year's visitor figures hold up -- and early indications suggest they will -- nine million visitors will see the Great Smoky Mountains, the most visited national park. Three other parks -- Grand Canyon (more than four million visitors in 2011) Yellowstone (about three million) and Acadia (more than two million) -- combined will attract roughly the same number."

"HOUSTON -- A Texas judge has ruled that the atmosphere and air must be protected for public use, just like water, which could help attorneys tasked with arguing climate change lawsuits designed to force states to cut emissions."

"For 80-year-old grandmother Espirita Lima Bautista, breathing while cooking over her kitchen hearth is like inhaling the second-hand soot of 400 cigarettes."