Mount Rushmore tourists hit with air quality warning - Air quality index values were estimated to have peaked at 161 at a key ...

Crater Lake National ... Quality. The three main qualities they look at are ground-level ozone, particle pollution, and nitrogen dioxide. At Crater Lake National Park, the air is so clear on ...

Analysis from the National Park Service and the Environmental Protection Agency shows Colorado’s already severely compromised air quality is worsening. The same sources of pollution harming health, ...

Nearly 90% of our more than 400 national park ... Great Smoky Mountains from air pollution. It has resulted in measurable and noticeable improvements in visibility and air quality across the country.