Disclaimer | Siting
This bulletin is updated hourly with data readings averaged over the previous 8 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.
Disclaimer: Data on EPA AirWatch comes directly from our air monitoring stations using various types of monitoring equipment and methods. This data may be adjusted later according to set criteria to account for instrument errors, power interruptions and other technical issues.
Siting: EPA aims to locate our ambient monitoring stations so they give a good representation of the air quality experienced by the public. As most of the Victorian population lives and works close to roads, most of our stations are in population centres next to roads. This can mean we do not always comply with one of the requirements of the Australian Standard for siting (AS 3580.1.1), which specifies that air monitoring stations should be more than 50 metres away from a road. Currently, Footscray is the only EPA air monitoring site that meets this requirement.
* 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 9.00 am to 10.00 am is available at 10.30 am. See the Q&A below for more information about station summaries, ‘not available’ and ‘offline’ reports.
- Morwell East: Monitoring for PM2.5 is offline due to technical difficulties and PM2.5 data is not being collected at the station. EPA technicians are working to fix the problem. (21 March 2017)
- Macleod: Monitoring for PM2.5 is offline due to the equipment being used in Incident Air Monitoring. (16 March 2017)
- Box Hill: Monitoring for PM2.5 is offline due to the equipment being used in Incident Air Monitoring. (16 March 2017)
- Humidity: Humidity can cause low visibility readings within EPA’s air monitoring network due to high levels of moisture in the air. EPA staff will monitor visibility readings during periods forecast for high levels of humidity and communicate any issues if required. (30 January 2017).
- Richmond: EPA is looking for a new site for its Richmond air monitoring due to problems with access at its existing location. Interim monitoring equipment will soon be installed in a location near Melbourne’s CBD to monitor PM2.5. Until the new location is confirmed, air monitoring data from Richmond will not be displayed. (16 September 2016)
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.
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