POLLUTION levels in Sydney's M5 East tunnel are so high that healthy motorists who use it daily could develop respiratory problems within two years, researchers have found.
The four-kilometre $800 million tunnel was last year labelled the world's dirtiest, with nitrogen dioxide levels up to four times higher than comparable tunnels around the world. Now a study has found motorists are exposed to ultrafine particulate matter - one of the deadliest air pollutants - at levels 1000 times higher than in suburban streets.
Ultrafine particles, which are less than 0.1 of a micron in size, are emitted by all vehicle exhaust systems, but particularly diesel cars and trucks. One large diesel truck can produce as much particle pollution as 20 cars.
The particles are so small they lodge deep in lung tissue, leaching into the bloodstream and causing respiratory disease and cardiac arrest in people with pre-existing conditions such as asthma, cardiac arrythmias and cardio-pulmonary disease.
''It's really quite dangerous I'd be advising anyone with asthma which is severe or unmanaged to avoid this tunnel if they can,'' the chief executive of Asthma Foundation NSW, Greg Smith, said yesterday.
''It is outrageous that it was built without a filtration system in the first place. It took a very long time to convince anyone this was a problem and now we are still waiting for it to be fixed.''
Researchers from Macquarie University and Queensland University of Technology travelled through the tunnel 306 times between 2006 and 2008, testing the air quality using a condensation particle counter to simulate the pollution breathed in by a motorist driving with the window down.
The levels of ultrafine particulate matter were so high that motorists suffering asthma, chronic pulmonary disease or influenza would feel its effects ''immediately or very soon after'', the lead researcher, Lidia Morawska, said.
''Even in a healthy person, with none of those conditions, chronic exposure in the form of using the tunnel daily for a year or two could lead to respiratory problems.''
Professor Morawska, director of the Queensland University of Technology International Laboratory for Air Quality and Health, said motorists driving convertibles or older cars that did not seal tightly, or those riding motorcycles and scooters, would be at a much higher risk, particularly as trips through the tunnel could take up to 26 minutes.
Last year's report by the National Health and Medical Research Council found the tunnel, used by more than 100,000 motorists a day, also had higher levels of carbon monoxide than most tunnels worldwide.
But the Minister for Roads, Michael Daley, said yesterday the Department of Planning had tested air quality in the tunnel in 2006 and had found no motorist had been exposed to levels of carbon monoxide above World Health Organisation goals.
''Since then, we've installed 12 extra jet fans to improve ventilation and a video detection system for illegal smoky trucks and both of these measures have made a marked improvement on the air quality in the tunnel over the last two years,'' he said.
A $50 million filtration system was being fitted to the western side of the tunnel and would be ready for use by early next year, while filters for the eastbound tunnel were still being reviewed
