Road tunnel air quality

Air quality in and around road tunnels

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.

Australia’s ambient (outside) air quality is regulated according to standards set under the National Environment Protection Measure: Ambient Air Quality. These standards were commissioned by the National Environment Protection Council.

The regulation and management of air pollution in Australia has meant that our air quality has been steadily improving since the 1980s. Data from the World Health Organisation shows that Australia has some of the cleanest air in the world

Roads and Maritime monitor ambient air quality around the M5 East Tunnel.

In-tunnel Air Quality (Nitrogen Dioxide) Policy

In January 2016, the NSW Government released a policy for emissions compliance in new tunnel projects to protect the health and safety of tunnel users.

The In-tunnel Air Quality (Nitrogen Dioxide) Policy sets a limit of 0.5 ppm for nitrogen dioxide emissions in all new tunnels more than one kilometre long to ensure air quality continues to improve over time.

An in-tunnel nitrogen dioxide compliance standard of 0.5 ppm - as a 15 minute rolling average across the whole tunnel – sets the benchmark in Australia and compares favourably to the international in-tunnel nitrogen dioxide design guidelines which range between 0.4 ppm and 1 ppm.

To stay alert, keep the fresh air flowing while you drive

While Sydney’s tunnels meet air quality standards set to protect public health, NSW Health advises that closing your windows and switching your vehicle ventilation to re-circulate will further reduce your exposure to vehicle emissions. These benefits can be achieved whether or not your air conditioning system is in use. However, leaving your ventilation on re-circulate for long periods of time can cause the air to become ‘stale’, which could lead to increased fatigue and a decline in your ability to concentrate. To stay alert, keep the fresh air flowing by opening your windows or changing the ventilation system settings every hour or so.

The M5 East Air Quality Improvement Program (AQIP)

The M5 East Air Quality Improvement Plan (AQIP) was launched in June 2006 in response to community concern about the level of haze caused by the high numbers of smoky heavy vehicles using the M5 East tunnel.

 The AQIP aimed to:

  • Improve the amenity of M5 East tunnel users, by improving in-tunnel air quality and reducing haze levels in the tunnel.
  • Ensure the amenity of residents at the tunnel entrances and exits (portals) and around the ventilation outlet, by meeting air quality goals and improving in-tunnel air quality.
  • Improve the availability of the M5 East tunnel by reducing the number of tunnel closures (resulting from air quality issues).
  • Assess the effectiveness of the latest in-tunnel air filtration systems to improve in-tunnel air quality.

The actions in the 2006 AQIP were reviewed and assessed to test their effectiveness. This led to the implementation of a stronger suite of measures, including the installation of 12 additional jet fans in the M5 East tunnel and a smoky vehicle camera/video system in the M5 East tunnel, as well as undertaking an 18-month trial of air filtration technology to see if air filtration was a viable air quality management measure for the M5 East tunnel.

For more information, read M5 East Tunnel Filtration Trial Evaluation Program – Review of Operational Performance

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