Air pollution in national parks is as bad as some of the largest metro areas in the U.S. — though the Grand Canyon National Park is a breath of fresh air in comparison, according to a new study.

At the center of the case is the cloud of haze that often hangs over the Grand Canyon and other federally ... As such, the air pollution violates the Clean Air Act's regional haze provision.

GRAND CANYON NATIONAL PARK — It's a calm ... Even when that rumor passed, there was still this smog, this pollution in the air that you could see. We knew it was the plant." ...

PHOENIX— Conservation groups today called on the state of Arizona to deny air-pollution permits for three uranium mines on the doorstep of Grand Canyon National Park. In comments sent to the Arizona ...

They then leave most of the removed material in tailing piles that contribute to water and air pollution. Kanab North Uranium Mine, located next to Kanab Creek, a tributary to the Colorado River on ...

Air pollution from China ... 16 national parks in the western U.S., including Yellowstone, Yosemite and Grand Canyon. The parks' locations farther away from cities, where smog is typically ...

Time-lapse images recently captured an incredible sight — a "tide" of clouds rolling into Arizona's Grand Canyon ... dramatically affect air quality by trapping pollution.