Black Canyon of the Gunnison National Park
Though remotely located in the mountains of northeastern Utah and northwestern Colorado, Dinosaur National Monument goes through days when the air quality is almost as bad as you'd find in major metropolitan areas.
“Running on empty” unfortunately is a very apt description of the Colorado River Basin, which long has had its water overcommitted. Today, the vast watershed that stretches from the mountains of Colorado to the Gulf of California and helps nourish some 30 million residents in the Southwest and Mexico is mired in a long-running drought that threatens to dramatically recast the already-arid region.
Unless things change, it will take centuries for many national parks to have truly clean air, according to the National Parks Conservation Association, which wants the Obama administration to close loopholes that stand in the way of improving air quality.