Nicole Javorsky is an editorial fellow at CityLab.
Jul 19, 2018
Bask in the views, not the air: the Grand Canyon of the Yellowstone River in Yellowstone National Park, Wyoming. Jim Urquhart/Reuters Even in Big Sky Country, you can’t escape from air pollution.
Even in the awe-inspiring canyons of Yellowstone and mountains of Yosemite, the fresh air may not be so fresh:Concentrations of ozone in many U.S. national parks are similar to levels in America’s largest metropolitan areas, according to a new study in Science Advances by researchers at Iowa State University and Cornell University.
Back in 1990, the biggest U.S. metro areas had higher average ozone concentrations and more exceedance days (when the EPA deems ozone levels unhealthy for sensitive groups) than national parks. Butbythe early 2000s, the study notes, ozone concentrations were “nearly identical” in national parks and large metro areas. In cities, average summer ozone levels decreased by more than 13 percentfrom 1990 to 2014. The same metric for national parks increased from 1990 to the early 2000s, but declined to 1990 levels by 2014.