This week, the Virginia Department of Environmental Quality announced that the summer of 2017 was the cleanest ground-level ozone season for the state in at least the last 20 years.
During this past summer, Virginia only had four days with ozone levels that exceeded the current standard, and those exceedances were limited in scope. Arlington and Fairfax counties each had four exceedances, while Henrico and Giles county each had one. All other areas of the state had no high ozone days in 2017. By contrast, the average number of high ozone days in the 1990s was 86.