Air quality in and around road tunnels

Roads and Maritime Services (formerly Roads and Traffic Authority) adheres to strict conditions set down by the NSW Department of Planning for the maximum allowable presence of vehicle emissions in the air both in and outside its tunnels. These standards are recommended by the World Health Organisation.

Air quality monitors in and outside the tunnels constantly measure the presence of carbon monoxide, nitrogen dioxide, fine particles and visibility levels.

External air quality in the suburbs adjacent to tunnels will vary during the year due to seasonal climate variations, wind speeds and external events such as dust storms, bush fires and construction works in the area.

Air quality management

Tunnel air quality is monitored 24 hours per day. It is managed by ventilating the tunnels with fresh air which dilutes the pollutants emitted from vehicles as they travel through the tunnels. Large fans push the air along the tunnels and expel the polluted air via the ventilation outlet(s). The height of the ventilation outlets and the speed at which it is expelled from the outlet ensures that the tunnel air is well dispersed. This prevents pollutants from accumulating at the ground around the ventilation outlets.

Leading the world in air quality reporting

Roads and Maritime Services (formerly Roads and Traffic Authority) leads the world in providing online streamed data and historical reports on air quality readings for Sydney's busiest road tunnel, the M5 East Tunnel.

Since opening in December 2001, the M5 East Tunnel has been operating within the ambient air quality goals set in the December 1997 Planning Minister's approval for the project.

Outside air (referred to as ambient air) quality readings for locations around the ventilation outlet can be found on Roads and Maritime Services (formerly Roads and Traffic Authority) website. To view the current readings for nitrogen dioxide, carbon monoxide, particulate matter and wind direction on the easy to use interactive map, click here.

CLEANER VEHICLES

As part of its commitment to continually improve air quality, Roads and Maritime Services (formerly Roads and Traffic Authority) is dedicated to reducing the impact of motor vehicles on the environment.  Roads and Maritime Services (formerly Roads and Traffic Authority) works with key NSW industry bodies to develop emission reduction programs and improve fuel quality standards.

Roads and Maritime Services (formerly Roads and Traffic Authority) continues work on national level programs to reduce emissions from vehicles. The Australian Government is progressively introducing tougher emission standards for petrol and diesel vehicles in line with stringent European standards. Fuel quality standards have been introduced to help get the maximum reduction in emissions from new engine technology.

Roads and Maritime Services (formerly Roads and Traffic Authority) has investigated the use of alternative fuels and has been involved in trials and testing the emission performance of various fuels. It also supports research into new engine and vehicle technology such as exhaust after-treatment devices that are used in the NSW Diesel Retrofit Program.

As a result of tougher vehicle emission and fuel quality standards and better engines, emissions from cars and trucks will continue to decline over the next ten years, continuing the trend of the last 30 years.

For more information on vehicle emissions, click here.