Tunnel air quality

NorthConnex has been designed to meet stringent in-tunnel and ventilation outlet air quality limits set by the NSW Environment Protection Authority and NSW Ministry of Health. Sampling and monitoring points are required to be established, and independently verified and audited in accordance with the Conditions of Approval. Once NorthConnex is open, there will be continuous air quality monitoring inside the tunnel and the ventilation outlets to demonstrate compliance with the air quality limits.

Ambient air quality

Part E of the NorthConnex conditions of approval specify pollutants to be monitored in the air surrounding the project (ambient air quality). These include Nitrogen Dioxide (NO2) and particulate matter (PM10 and PM2.5) which have ambient goals that if exceeded, trigger reporting and investigation to determine if emissions from the tunnel outlets contributed to exceedances.  The ambient air quality notification protocol is being developed for approval by the Department of Planning and Environment in consultation with the EPA, NSW Health and the Air Quality Community Consultative Committee (AQCCC).

Local weather conditions are also monitored to understand their effect on air quality.

To understand more about air quality visit the Roads and Maritime air quality portal. 

There are currently six monitors operating outside the tunnel to measure the ambient air quality. The locations, determined in consultation with the Air Quality Community Consultative Committee, are listed below:

  • James Park, Hornsby
  • Carden Park, Wahroonga
  • Thornleigh Golf Centre, Thornleigh
  • Headen Park, Thornleigh
  • Ashley Avenue, West Pennant Hills
  • Larchmont Place, West Pennant Hills

Data from these monitors will be collected for at least 12 months to provide baseline measurements for when NorthConnex opens to traffic. The monitors will continue to operate for at least two years after the tunnel opens.

Monitoring results

All air quality results are independently collated and audited every six months. Click here to see real time data from the NorthConnex ambient air quality monitors. Reports are prepared at the beginning of each month to summarise the results of the previous month. All available reports are listed below.

Month/Year

Report summary

January 2018

There were no exceedances of the air quality goals at the NorthConnex Ambient Air Quality Monitoring Network for the reporting month. Please refer to Table 13-18 in Section 5.2 of the report for more information.  


Previous reports


December 2018
November 2018

If you would like a hard copy of any of these reports, please call the project information line on (free call) 1800 997 057, email enquiries@northconnex.com.au, or write to us at Community Relations Team, Locked Bag 1001, West Pennant Hills, NSW 2125.