Analysis of West Gate Tunnel Project air monitoring data

The Victorian Government’s Air Quality Strategy and Air Quality Improvement Precincts aim to improve air quality in Melbourne’s inner and outer west. These programs help make sure strong science and data are the basis of the decisions made about:

• air quality
• health
• the environment.

As part of this work, we have been working with the Inner West Air Quality Community Group and Network to better understand local air pollution. We’ve compared data from West Gate Tunnel Project stations with other air monitoring stations in:

• Alphington
• Brooklyn
• Footscray
• Melbourne CBD.

The first air quality report covers July 2016 to December 2022. The updated report includes data through to the end of December 2024. Both reports compare air quality results to the Victorian Environmental Reference Standard (ERS).

Levels of airborne particulates (PM_2.5 and PM₁₀) changed over the years at all stations. These changes were caused by local air pollution sources and weather. All stations recorded particulate levels above the ERS at some point between 2016 and 2024. How often and how long these levels stayed high varied by location.

The main causes were:

• smoke from the 2019–20 bushfires
• local pollution from industry and transport
• smoke from wood heaters.

Some years had lower air pollution levels. This may be due to less activity during the pandemic, fewer bushfires in 2021 and La Niña impacting weather in 2022, which helped reduce particulate levels.