An 18 month trial of air filtration technology in the M5 East westbound tunnel commenced on 9 March 2010.

The objectives of the trial include:

• Evaluating the ability of the plant to reduce levels of nitrogen dioxide and particulates in the tunnel.
• Evaluating the ability of the plant to reduce haze levels (particularly at the western end of the westbound tunnel).
• Assessing the amount of electricity used to run the fans and equipment, and the resulting generation of greenhouse emissions.
• Understanding the operating performance including factors such as reliability, shutdowns and maintenance requirements and the limits of the technology.

The plant does not run 24 hours a day. Roads and Maritime Services (formerly Roads and Traffic Authority) is testing the equipment at different times of day and in different environmental and traffic conditions, which provides information about the best times to operate the filtration plant to achieve best results.

The information gained throughout the trial is being used to evaluate the requirements for similar equipment in existing and future road tunnels.

For more information on the filtration plant and its equipment, click here.