Notes according to data source:
• Prior to 2008, the 8-hour ozone exceedance day tables reflect the 1997 federal standards of 84 ppb.
• From 2008 forward, the tables reflect the 2008 federal standards of 75 ppb.
• Tables from 2016 forward reflect the 2015 federal standards of 70 ppb.
• The ozone season was expanded in 2017 to include March through September.