Australia’s tunnels among world’s worst: Report

A national report on road tunnel air quality has found that levels of toxins in Australian tunnels are much higher than international averages, reinforcing long-held concerns that the health of commuters and residents are at risk.

The report, released this month, was commissioned by the National Health and Medical Research Council in response to a request for health advice from the Australian Government Minister for Health and Aging.

It found that Sydney’s M5 East tunnel is one of the most polluted tunnels in the world and poses significant health risks for those using the tunnels, as well as residents. At four kilometres and carrying 100,000 vehicles per day, it was pinpointed as being particularly congested.

Average nitrogen dioxide concentrations in tunnels around the world were mostly around 50-150 parts per billion, however the M5 East recorded levels of over 200, the report states.

The report also found cause for concern over several pollutants including nitrogen dioxide and particulate matter. Recommendations include the development of a health-based exposure limit for NO2 and PM “as a precautionary interim measure.”

“This review found evidence suggesting that short-term exposure to NO2, PM and diesel exhaust particles in particular pose risks to health.”

It also stresses the increasingly evident need to effectively monitor and cut fine particulate matter, as there is evidence that levels and concentration of the pollutant are increasing.

“Particulate matter levels should be monitored with a view to reduction, as current levels in some tunnels in Australia are… clearly dangerous to health.”

“There is general agreement that ultrafine particles possess significant toxicity, but exposure limits have yet to be defined… the review found some studies suggesting that emissions and concentrations of particle numbers may be increasing.”

These pollutants are known to cause, or worsen, a string of health effects including asthma, heart attacks and cancer.

“Concentrations of NO2, which do or could arise in Australian tunnels present cause for concern. Within a tunnel, brief but intense exposures to NO2 and PM may aggravate asthma.”

“For people living near tunnel portals, particulates and NO2 exposure may be the most critical in terms of general health. If VOC (eg benzene) exposure is increased, then there will be an associated increase in the lifetime risk for cancer.”

It also stressed the need for more research and monitoring into tunnel air quality, an area in which information has often been hard to find.

“The interaction between road traffic pollutants, especially in terms of the effect on living tissue, remains a major area of uncertainty.”

The report also emphasized the difficulty of obtaining data about some Australian tunnels, which adds to the mistrust between the public and the tunnel operators.

“We would first like to comment on how difficult it was to obtain data about some Australian tunnels, especially where private operators were involved. In some cases this hindered our analysis. Such an approach to data management is unhelpful and contributed to the mistrust that has arisen in some cases between tunnel operators and relevant government agencies on the one hand, and the general public and concerned community groups on the other.”

A clear message has been sent to tunnel operators to start monitoring pollutants that have been, until this point, ignored, and to make information more accessible to the public in order to reduce mistrust.

Michael Daley, the Minister for Roads, said in a recent statement that work on the filtration project was "on track to be finished late next year" after work began in April.

"The construction of the filtration plant is just one component of the Government's air quality improvement plans for the M5 East," he said.

"The plan also includes a video detection system for illegal smoky trucks and 12 extra jet fans to improve ventilation, both of which are already operating."

18-11-2008

Kate Schneider