Even though the Clean Air Act has been in effect for almost four decades, many national parks are still dealing with haze. An environmental group has called on the Obama administration to clean up the air pollution at a much faster rate.
The Grand Canyon has lost 42 miles of visibility to haze pollution, according to the National Parks Conservation Association.
"Unfortunately the rules EPA did write have so many loopholes that by our calculation and at EPA's own calculation it will take centuries to achieve clean air at the country's most iconic national parks like the Grand Canyon," said Mark Wenzler, a spokesman for the National Parks Conservation Association.
Wenzler said several old industrial plants still need to install modern emission scrubbers.
According to the Environmental Protection Agency's website, Clean Air Act programs have lowered levels of six common pollutants and dramatically improved the quality of the air that we breathe.
Out of 52 required Regional Haze State Implementation Plans, there are 45 plans in place to ensure control of emissions that impair visibility in national parks.
The EPA plans to address the remaining few states by the end of the year.
