The Air Quality Index compiled by the Victorian Environment Protection Authority measures the concentration of various pollutants relative to the concentration levels at which they may cause harm. The lower the index is, the better the quality of our air. The index is available for four areas in the Port Phillip Region (East, West, City and Geelong) and the Latrobe Valley.
The Visibility Pollutant Index is an indicator of visibility reduction, and is measured by the concentration of airborne particles relative to Victorian standards. Incidents of poor visibility are generally higher during the cooler months of autumn and winter (from May to September), whereas ozone levels are generally higher during the warmer months of spring and summer (from November to February).
View underlying table as an Excel spreadsheet: Download Air quality, By Region from the Downloads Page.