About EPA air quality bulletins
EPA measures a range of pollutants at each of its monitoring stations. Each pollutant has a different impact on human beings or the environment. The State Environment Protection Policy (The Air Environment) (SEPP) sets objectives for these pollutants.
A National Environment Protection Measure (NEPM) for air has also been developed. This sets nationally agreed air quality standards for a range of pollutants. There is one exception: visibility – where the current SEPP objective will continue to apply.
Currently EPA 24-hour summary air quality bulletins are issued twice daily (approximately 9.45am and 3.45pm) from Monday to Friday and daily (3.45pm) on weekends. Hourly data is available 24 hours a day, seven days a week on this website.
Air quality categories
Data in EPA air quality bulletins are expressed in terms of an air quality index. EPA has also adopted five-colour coded air quality categories. Data is assigned to a category based on the index value as listed in the table below.
|Very good air quality||0–33|
|Good air quality||34–66|
|Fair air quality||67–99|
|Poor air quality||100–149|
|Very poor air quality||150 or greater|
|A grey background indicates that the monitoring station is not instrumented for the pollutant or data is temporarily unavailable.|
Determination of an overall station summary
The station summary is determined after a check to see whether or not enough data have been measured to form a useful summary of air quality. This check involves ensuring at least one pollutant of major concern has been measured. In Victoria:
- Particles (PM10) and visibility reduction are the pollutants of major concern from May to September.
- Ozone, particles (PM10) and visibility reduction are the pollutants of major concern from October to April.
A station summary of GOOD or VERY GOOD can only be formed if at least one of the pollutants of major concern is being actively recorded. However, if any pollutant (either major or not) is found to cause air quality to be FAIR, POOR or VERY POOR then a station summary will be generated.
Some stations may not record enough data to form a valid summary because they are designated for special purposes, or because of instrument failures.
If the check shows enough data are present, then a summary (VERY GOOD, GOOD, FAIR, POOR or VERY POOR) will be shown according to air quality category (see above table).
If a useful summary cannot be formed, the words not available will appear in the summary column.
If no data at all are present for the station, the word off-line will appear.