Ozone Exceedance Summaries

The Excel files in this listing display what we call the Ozone Exceedance Summary for the ozone season. Ozone season officially runs from April 1st through September 30th. Since exceedances have occurred in March, every effort is made to bring the monitors back up as soon as practical each year. Ozone season is likely to start earlier and end later now that the ozone standard is lower.

The summary includes the date and monitor name(s) with the highest 8-hour average for the day when an 8-hour ozone average exceeded the current National Ambient Air Quality Standard of 0.075 parts per million.

The cells containing the maximum 8-hr ozone average for each site have background colors associated with the appropriate category of the Air Quality Index.

Any site names with an asterisk and a background color of light blue are associated with a note which states that the exceedance occurred during the overnight hours due to ozone build up the previous day. When this occurs it may change the total number of exceedance days for that year. This is indicated at the bottom of the table when appropriate.