Air pollution in national parks such as Yellowstone, Yosemite and Acadia is as bad as some of America's largest cities, and the foul air may be causing tourists to cut visits short or avoid going at all, according to a study released Wednesday.
“Even though the national parks are supposed to be icons of a pristine landscape, quite a lot of people are being exposed to ozone levels that could be detrimental to their health,” said study co-author Ivan Rudik of Cornell University.
Researchers from Iowa State and Cornell said visitor numbers dropped almost 2 percent when ozone levels went up even slightly and at least 8 percent during months with bad air quality. Health concerns for visitors were more of a worry than poor visibility...