Science Centres: Energy

Advice to the Aussies on tunnel pollution

When the Australian government needed an independent expert opinion on the health risks of air pollution from urban road tunnels, it chose a New Zealand scientific team.

Across the Tasman, huge urban motorway projects are underway involving extensive use of tunnels. Sydney’s Orbital Motorway now has 14 km of tunnels, and up to 20 km of tunnels are mooted for central Brisbane. This has stirred up communities; many local residents believe pollution from tunnel chimney stacks is affecting their health.

The Australian government hired NIWA scientist Ian Longley, and Francesca Kelly of Environ Medical Services, to review the levels of pollutants in and near tunnels, the risks of health of residents and tunnel users, and what can be done to manage that risk. Both Ian and his NIWA colleague Gustavo Olivares have worked on traffic impacts in Europe.

Overall, the study found negligible health risks to local residents but a small risk to tunnel users, especially when traffic is backed up
or for people vulnerable to respiratory or cardiovascular problems. “Calculating individual exposure to harmful pollution and assessing potential health effects is challenging but the public deserves full protection,” says Ian.

The recommendations included developing a new exposure limit for nitrogen dioxide for tunnel users. “The composition of vehicle
emissions worldwide is changing, with nitrogen dioxide becoming more significant as total emissions and carbon monoxide levels
reduce,” says Ian. “As a result, previously effective air quality management measures in tunnels are becoming less relevant.”

The full report will shortly be available at www.nhmrc.gov.au