Ozone AQI Breakpoints
The AQI breakpoints for ozone were updated on June 21, 2016 to be consistent with the 2015 ozone standards. This update applies to all historical data as well. For more information, see the table on page 2 of the Updates to the Air Quality Index (AQI) for Ozone and Ozone Monitoring Requirements (PDF).
Plot daily AQI values for a specific location and time period. Each square or “tile” represents one day of the year and is color-coded based on the AQI level for that day. The legend tallies the number of days in each AQI category.