"The Environmental Protection Agency has released a major upward revision to its estimates of total emissions of methane, a hard-hitting if short-lived greenhouse gas, in an annual inventory that the agency submits to the United Nations. The revisions will further up the stakes in a political battle over regulations that the agency is preparing to issue that could affect operations at thousands of oil and gas wells."

"As Pennsylvania’s natural gas production continues to expand, so does the possibility of potentially harmful methane emissions."

"Industry groups are challenging President Obama’s rule to protect workers from exposure to harmful silica dust."

"As Southern California continues to battle the nation’s worst smog, most members of a powerful regional panel that enforces air pollution regulations can breathe relatively easily. Nine of the 13 members of the South Coast Air Quality Management District live close to the ocean in Los Angeles or Orange counties, where ozone, the hallmark pollutant of summer smog, exceeds federal health standards fewer than 10 days a year."

"A half dozen coal-fired power plants in Georgia face tougher federal rules that could force them to spend millions of dollars, or even shut down some, to reduce heavy metal pollutants in the state’s rivers and ground water."

"MEXICO CITY — Metropolitan authorities on Wednesday temporarily ordered all cars to remain idle one day a week in response to this notoriously smoggy capital's worst air-quality crisis in over a decade."

"16,000 preterm births a year are linked to fine particulate pollution, costing the US $4.33 billion annually".

"The Federal Trade Commission (FTC) has sued Volkswagen Group of America, accusing the car manufacturer of running deceiving advertisements for so-called “clean diesel” vehicles that in fact were designed to evade federal emissions tests."

"Federal inspectors are investigating whether glass makers outside Oregon are emitting the same toxic chemicals that landed two Portland art glass makers in the spotlight, records show."