The EPA developed the Air Quality Index, or AQI, to make information available about the health effects of the five most common air pollutants, and how to avoid those effects. The following figures provide this data using the AQI to break things down by Ozone, PM2.5, and overall air quality levels in the Austin-Round Rock-San Marcos Region. These figures are typically updated in the first week of a new month. Click the Select AQI dropdown menu at the top left to switch the data view between Overall AQI, Ozone, and PM (Particulate Matter). Click the Year dropdown menu to filter the charts and view data from a specific calendar year.