In just twenty minutes on the Stockholm tunnelbana, passengers are exposed to the same amount of pollution as a 24 hour stint on Hornsgatan, the capital’s most traffic-laden street.
According to a new study conducted by Stockholm’s Karolinska Institute, a large number of particles found on the tunnelbana consist of extremely small metal fragments from the rails and the trains’ brakes.
Such particles could be up to eighty times more harmful to people’s lungs than those found on the street.
As reported in Tuesday’s Dagens Nyheter, researchers have tested lung cells which have been cultivated in a laboratory. The cells have been exposed to both particles from Hornsgatan and from a nearby underground station, Mariatorget.
Speaking to DN, Lennart Möller, professor in toxicology from Karolinska Institute said exposure to polluted air not only increases the risk of lung and heart disease but also the genetic make-up of humans.
“The tunnelbana particles are much more powerful in harming the DNA cells. They are eight times more powerful,” he added.
At present, researchers are unable to explain to what extent the tests on cultivated lung cells could mean to human cells. But, they say, it should be investigated further.
Tuesday’s Aftonbladet stated that the research shows no evidence of an immediate threat to public health. But, with 600,000 people using Stockholm City transport every day, attention needs to be drawn to the issue.
“In so far that it is a public environment, something must be done,” Professor Möller added.
The study will be published in the next edition of the American periodical Chemical Research in Toxicology.