A recent study shows that air quality on the London Underground is, well… it’s pretty damn awful.
According to an official report, the concentration of particulate pollution in tube stations is 20 times higher than the air beside busy roads in the city. There are 250 micrograms of per cubic metre vs 13.7 micrograms when walking outdoors.
The Committee on the Medical Effects of Air Pollutants (COMEAP) told TfL that, “Given that there is strong evidence that both long- and short-term exposure to particle pollutants in ambient air are harmful to health, it is likely that there is some health risk.”
Tests found that the Northern line had the highest concentration of particles linked to health problems (no surprise there). But it was Hampstead station, the deepest on the entire tube network at 200ft below ground level, that scored the title of The Very Worst Place – recording an average of 492 micrograms per cubic metre (μg/m3) of air, compared to just 16 μg/m3 from a roadside monitoring site in London.
The tube is supposedly worse than any other subway system, due to the age and depth of the tunnels. To put it simply, and shockingly, tube passengers are exposed to the same concentration of particulates in one hour on the Underground as a full day above ground.
A bus journey on the other hand, despite sometimes taking more than twice as long, would expose a passenger to a third of the air pollution.
The report explains that the dust we inhale underground is heavier and more metal-based than the smaller, carbon-based particles up above in the fresher air. However, more evidence is needed to show us whether or not this actually has any harmful effects on passengers. At the moment, COMEAP don’t have a clear understanding but suggest that, as we’re generally down there for such a short amount of time, we’re probably alright.
The London Underground operates well within the Health and Safety Executive specified limits, but TfL have set themselves an “informal target” and have agreed to try and limit passengers’ exposure to dust.