The Sydney region is bordered by the Hawkesbury River in the north, the Blue Mountains to the west and the southern bounds of the Wollondilly and Sutherland Shires in the south.
Air quality in Sydney varies greatly depending on topography and climate. The predominately flat Cumberland Plain in Sydney’s west sits below the Blue Mountains, resulting in a gradual decrease in rainfall and an increase in temperature further from the coast.
The north-easterly sea breeze during summer further impacts how air quality levels differ across Sydney, meaning northern parts of the Cumberland Plain have different air quality characteristics from areas in the north.
These geographical differences, along with population distribution have resulted in four Sydney sub-regions with distinct air quality characteristics:
Monitoring and reporting
The Department currently operates 21 air quality monitoring stations in Sydney, one of which is a temporary research station. These stations are spread out across each of the four sub-regions:
- Sydney East: 8 stations (including the temporary research station at Cammeray)
- Sydney Central west: 4 stations
- Sydney North West: 3 stations
- Sydney South West: 6 stations
Using data from these stations, we provide hourly updated air quality categories (AQC).
For details of our monitoring program, see the Air Quality Monitoring Plan for the Greater Sydney Region 2021–25 (PDF, 2.3 MB).
You can find more information on Sydney’s air quality compliance with national standards in the annual NEPM reports, and comparisons with the rest of New South Wales in the latest Annual Air Quality Statement.
Research studies on Sydney air quality
Early studies of air quality in the Sydney region included the Sydney Oxidant Study (in the late 1970s), the Metropolitan Air Quality Study (MAQS, 1992–1995) which focused on photochemical ozone and fine-particle pollution, and the Ambient Air Quality Research Project (1996-2001) which studied air toxics.
- The Air Pollution Economics: Health costs in the Greater Sydney Metropolitan Region (PDF 394KB) study published in 2005 estimated the cost to health of ambient air pollution.
- The Ozone State of Knowledge study, completed in 2010, consolidated and expanded knowledge on ground level ozone pollution and events contributing to high ozone levels in the Sydney, Illawarra and the Lower Hunter regions.
- Recent research studies which have expanded the evidence base on the composition and sources of particle pollution in Sydney include the Sydney Particle Study (completed in 2013) and the 15-year Sydney Particle Characterisation Study (published in 2017).
- Research into trends, sources and impacts of air pollution is ongoing as part of the Sydney Air Quality Study. Air quality forecasting for Sydney is progressively being improved as part of the Enhancing Air Quality Forecasting in NSW research program.
- The Air Emissions Inventory for the Greater Metropolitan Region in NSW, which is updated every five years, provides detailed information on sources of air emissions in Sydney.