"The U.S. Environmental Protection Agency staff said Friday that the nation should tighten smog rules significantly, a step that would improve air quality in California but force costly new requirements on government and industry."

"There are some countries in the world where the air is so polluted you can forget about coming home with a healthy holiday glow."

"WASHINGTON - The United States has made progress in reducing dangerous air pollution since 1990 but work remains to reduce risks for the country's most overburdened urban areas, the U.S. Environmental Protection Agency's top official said on Thursday."

"New research from NASA's Goddard Space Flight Center shows that large quantities of a chemical responsible for depleting the ozone layer are still being emitted, even years after an international ban."

"Drilling-wary Maryland is one of several East Coast states considering whether to open their lands to fracking as public health concerns mount."

"SAN FRANCISCO — The threats from climate change are many: extreme weather, shrinking snowpack, altered ecosystems and rising and more acidic seas, to name a few. Another lesser-known issue may hit especially close to home for city dwellers. In the world’s already smoggy metropolises, pollution is likely to grow worse, a phenomenon scientists have taken to calling the climate penalty."

"U.S. EPA has denied a petition from environmentalists to name nearly 60 areas of the country out of compliance with the federal ozone standard."

"EDMONTON -- Warnings about higher levels of air pollution in the oilsands have emerged in a new provincial air quality report that calls for further investigation into possible pollution sources."

"Energy Secretary Ernest Moniz announced new actions Tuesday aimed at curbing methane emissions form the nation's natural gas systems."

"It didn’t smell when Brittney Willis closed on her Midtown condominium on Halloween of 2011."