Tunnels are 1,000 times more polluted than open roads


Sydney : A dangerous cocktail of ultra fine particles, lurking inside tunnels, makes them up to 1,000 more polluted than open roads, says a new study.

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“The results show that, at times, the (pollution) levels (in tunnels) are up to 1,000 times higher than in urban ambient conditions,” said Lidia Morawska, study co-author and professor at the Queensland University of Technology (QUT).

Accordingly, the maximum exposure to dangerous ultra fine particles, besides other pollutants, takes place in tunnels, said Morawska, director of QUT International Lab for Air Quality and Health.

“Effects can range from minor respiratory problems in healthy people, to acute myocardial infarction (heart attack) in people with existing heart complaints,” she added.

Morawska said the study involved more than 300 trips through the four km M5 East tunnel in Sydney, with journeys lasting up to 26 minutes, depending on traffic congestion.

She said drivers and occupants of new vehicles which had their windows closed were safer than people travelling in older vehicles.

“People who are driving older vehicles which are inferior in terms of tightness and also those riding motorcycles or driving convertibles, these people are exposed to incredibly high concentrations,” she said.

“When compared with similar studies reported previously, the measurements here were among the highest recorded concentrations,” she said.

Morawska said tunnels were becoming an increasingly necessary infrastructure component in many cities across the world.

These findings were published in Atmospheric Environment.