Australian television network Channel Nine recently featured a news report on traffic pollution in Sydney's road tunnels. Using Turnkey's portable DustMate monitor, they set off to record dust levels around the city.

Results for PM₁₀ ranged from well within safe levels in the suburbs to several times the recommended level of 50 μg m^-3 in the busiest tunnels. The M5 tunnel was particularly severe, with an average PM₁₀ of 350 μg m^-3 (and a peak of 4000 at one spot).

The raised levels have been blamed on poor ventilation and heavy traffic. A trial of a new filtration system for the M5 was due to start recently.