Using the Underground exposes travellers to more cancer-causing air pollution than is safe, according to a new study.
Scientists at the University of California found that toxin levels on one of Los Angeles’ busiest subway lines were ten-times higher than those seen as acceptable by international health organisations.
These worrying results should be even more concerning for London commuters, as the city’s Tube network is even busier than the subway in Los Angeles.
While the outcome of the study suggests that such systems need to be better ventilated so toxins can’t accumulate, another option is to avoid the Tube and commute by coach instead.
One of the contributing factors to air pollution in subway networks is the fine dust that is created by train carriages grinding against the steel rails.
The chromium in the steel undergoes a transformation when heat or friction is applied and turns into hexavalent chromium, a compound that is known to cause cancer.
Without proper ventilation, this dust collects in all sorts of places – from underground tunnels to train cars – and is harmful when breathed in.
Hexavalent chromium is just one of many fine air pollutants called polycyclic aromatic hydrocarbons (PAHs) that are so fine they easily enter the body and become embedded in the lungs and other organs.
The compound is associated with the development of nasal and sinus cancers, liver and kidney damage, and skin and eye irritation.
There is little that can be done to protect against them, apart from avoiding places where they are prevalent, such as subway systems.
Approximately 2.18 billion passengers travel on the London Underground every year and it is those who are using it for their daily commute who are most at risk.
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