A new study released on Wednesday in Science Advances suggests that “from 1990 to 2014, average ozone concentrations in national parks were statistically indistinguishable from the 20 largest U.S. metropolitan areas.” Typically when you envision a national park, fresh, clean air comes to mind, but now this study wipes those pleasant thoughts away.
According to Ivan Rudik, co-author of the study and assistant professor of applied economics at Cornell University, “Since the early 2000s, air quality (as measured by ozone) is just as bad (or just as good) in national parks as it is in metropolitan areas.”
It was found that in the year of 1990, metropolitan areas had higher average ozone concentrations than in the national parks by a significant number — until now: “Summertime ozone concentrations and the average number of unhealthy ozone days are nearly identical in national parks and metropolitan areas starting in the 2000s. Average summer ozone concentrations decreased by more than 13% from 1990 to 2014 in metropolitan areas. Meanwhile, summertime ozone levels increased in parks from 1990 to the early 2000s and decreased thereafter to 1990 levels by 2014.”
Interestingly, the national park found to have the greatest ozone pollution was Sequoia National Park. This park follows a similar amount of exceedance days (days when the daily maximal 8-hr-average ozone concentration exceeds 60 ppbV or when the air quality is at least unhealthy for sensitive groups) as the city of Los Angeles.
The study also notes how there is a direct correlation between the number of park visitors and high ozone levels. When the air quality is worse, indicating higher ozone pollution, park visitation was reduced: “”Still, 35% of all national park visits occur when ozone levels are elevated.”
Despite this discouraging study, most days of the year are safe for most park visitors at the national parks and everyone is encouraged to enjoy the great outdoors the US has to offer.
These Are the National Parks Most Harmed By Air Pollution: