Air quality monitoring
Diagram of the air monitoring network
The instruments measure air quality continuously and data is collected by loggers which poll each instrument every 10 seconds. This data is averaged over 30 minutes and is stored in the logger memory.
The averaged data is recovered automatically from the stations at three-hourly intervals throughout the day through switched telephone and mobile phone networks.
The recovered data is stored on a central computer at the Air Quality Sciences branch of the department and undergoes a preliminary quality check to ensure it is valid. Invalid data may result from instrument malfunctions or disturbances to measurements due to calibration or maintenance. This preliminary validated data is transferred to a database on the the department's web server and the Air Quality Index is calculated using this data.
The data is then displayed on a dynamic web page on the the department's website where it is colour-coded to indicate the air quality. The data updates every three hours. The web page also allows users to select air quality or meteorological data from any monitoring site, for any date and time back to the year 2000, and to view an hourly data table or plot data for a day, week, month or year in a linear or polar format.
The data remaining on the central database undergoes a more intensive validation process where the data is checked against daily calibration values, maintenance records and known environmental conditions (e.g. bushfires, dust storms and construction works) and is used for monthly and annual reports, and for data requests. A copy of the fully validated hourly data is then uploaded to the web page.