America's Most Polluted Park

"Over the past few years, ozone at Sequoia for an average of 56 days annually has exceeded the national clean-air benchmark established by the U.S. Environmental Protection Agency. Stated more explicitly, ozone reaches or exceeds the standard of .08 ppm eight hours a day, one day out of six during the year. It is a level that is harmful for human health, and it is anathema to the aesthetics of a national park. On clear days you can see 100 miles from Beetle Rock, but park officials say visibility on the worst summer days is less than 10 miles."