Tunnel air quality

WestConnex | Transurban operate the M5 East motorway, which provides motorists with a journey between the City, Sydney Airport, Port Botany and Sydney's South-Western suburbs. The asset operates in accordance with Conditions of Approval established by the NSW Government.

Monitoring and measuring protocols for each pollutant and parameters are described in the glossary of terms. A Pollution Incident Response Management Plan is also in place as a requirement of the Environment Protection Licence.

The external ambient air quality monitoring shows data for:

  • Carbon monoxide (CO)
  • Nitrogen dioxide (NO2)
  • Particles less than 2.5 micrometers in diameter (PM2.5)
  • Particles less than 10 micrometers in diameter (PM10)
  • Standard deviation in wind direction (Sigma theta)
  • Temperature at 2 metres (ºC)
  • Temperature at 10 metres (ºC)
  • Wind direction (degrees)
  • Wind speed (m/s)

Air Quality in NSW, particularly visibility and particle concentrations, may be impacted from both natural sources (such as weather, fires or dust storms) and human activities. We encourage you to visit NSW Office of Environment and Heritage website for a daily update on Sydney’s current and forecast air quality.

Pollutant measuring locations

 External ambient



The data uploaded to this website comes from air quality monitoring instruments and sensors installed in and around tunnel(s). Ambient air quality data is collected by third parties and may be subject to instrument or communication faults, weather or other environmental events, or server issues.

The data used in the compilation of this page has undergone only preliminary quality assurance checks. This data must be preliminary until a monthly quality assurance check/validation process has been undertaken by a person or organisation accredited by the National Association of Testing Authorities (NATA). For further detailed description and explanation of the quality assurance and data validation process, visit the Office of Environment and Heritage.

Validated data will become available on this page approximately one month after the end of the calendar month. For example, the January data which has been validated will become available at the end of February. Validated air quality data reports are published monthly on this page.

If you require more information or have questions about our site's disclaimer, please feel free to contact us by email at info@westconnex.com.au.