"The Obama administration on Tuesday finalized new fuel-economy standards for large trucks, buses and other heavy-duty vehicles, the latest in a series of efforts aimed at slashing greenhouse gas emissions and weaning the nation from its dependence on fossil fuels."

"A puzzling concentration of the greenhouse gas methane over the Southwestern United States appears to come mostly from leaks in natural gas production, scientists said Monday."

"Long-lasting white trails left behind by aircraft are caused by well-understood physical and chemical processes, not a secret, large-scale atmospheric spraying program, concludes new research from Carnegie Science, University of California-Irvine, and the nonprofit Near Zero."

"We may be in the clear when it comes to heat domes, but it’s still really hot. More than half the country could see temperatures in the 90s by the end of the week, and if that forecast comes true, you may find relief in the cool, crisp breeze of an air-conditioner. But in the next few years, the way air-conditioners work could change."

"The auto industry will need to step up introduction of fuel-saving technology to help the U.S. meet aggressive goals to combat climate change despite manufacturers’ requests for relief from existing rules, the Environmental Protection Agency’s top transportation official said."

"Rio de Janeiro's air is dirtier and deadlier than portrayed by authorities and the Olympics' promised legacy of cleaner winds has not remotely been met, an analysis of government data and Reuters' own testing found."

"Exposure to more intense shale gas development correlates with a higher risk of asthma attacks among asthma patients, according to a new study of Pennsylvania's Marcellus Shale, one of the nation's largest and most active fracking regions."

"Concluding a long legal climb to cleaner air, the federal government Monday announced a record $425-million settlement with two oil refiners that is expected to reduce pollution emissions in the West by almost 43,000 tons annually."

"Under new rules announced by the Environmental Protection Agency (EPA) on Friday, solid waste landfill operators must begin capturing methane emissions from their sites at levels one-third lower than current standards permit."

"Outside Susan Holmes' house in southeastern Oklahoma, visitors are welcomed by an entryway lined with oxygen bottles and a machine that collects and concentrates oxygen from the air."