This bulletin is updated hourly with data readings averaged over the previous eight hours for carbon monoxide, the previous 24 hours for PM2.5 and the previous hour for PM10, ozone, nitrogen dioxide, sulfur dioxide and visibility reduction. Detailed information on the calculation of the air quality index (AQI) is available below.
Please see the summary below for an indication of expected air quality. On occasion, data may not show on the table below for a variety of reasons, such as monitoring station maintenance, equipment breakdown or website issues. See current notices below.
During winter months, EPA switches off equipment that we use to monitor summer ozone in parts of our network (mostly in metropolitan Melbourne). We will switch them back on before the start of next summer.
*Important information about monitoring PM2.5
As of 28 June 2015 EPA now reports on PM2.5 levels at nine additional sites. These are: Box Hill, Brighton, Dandenong, Mooroolbark, Altona North, Melton, Point Cook, Macleod and Wangaratta. At these sites, PM2.5 is measured using portable air monitoring monitors. All other stations that record PM2.5 use a monitor called a BAM (beta attenuation monitor). These monitors produce data that is a rapid assessment of PM2.5 levels in an area. EPA has done work with these types of monitors that shows they can correlate well with measurements from a BAM. We are currently working to better understand the precision of this equipment. We are doing this by comparing data from portable monitors with data from other types of particle monitors. These mobile instruments provide the community with a more flexible air monitoring network by allowing EPA to monitor air quality at a greater variety of sites. Find out more about the differences between the different kinds of air monitoring equipment and methods.
Data for a given hour are available at 30 minutes after the following hour. For example, data for the period from 9 am to 10 am is available at 10.30 am. See the Q&A below for more information about station summaries, ‘not available’ and ‘offline’ reports.
EPA collects air quality data using a variety of different monitoring instruments, which are placed in strategic locations – these instruments make up our ‘air monitoring network’. Find out more about EPA’s air monitoring network and what we monitor.