New research suggests that ultrafine particle dust on underground railways could pose a risk to public health, according to a new study.
Research published in the journal Environmental Science and Technology suggests that the dust found in underground railways is different than above-ground, therefore travelling or working on an underground railway for a sustained period of time could have health implications due to concentrations of metal-rich microscopic dust particles that can penetrate the lungs.
A team at the University of Southampton studied the particles found in an underground station in Europe and it turned out to be unusually high in metals.
Lead author of the study, PHD student Matt Loxham, said, “The high level of mechanical activity in underground railways, along with very high temperatures, is key in the generation of this metal-rich dust.”
Scientists studied the ultrafine particulate matter (PM0.1) found in an underground station beneath an airport in Europe and found there were similar concentrations of airborne metals in the dust particles in heavily-trafficked road tunnels and wood burning stoves.
Working in steel mills and other environments that are rich in airborne metals has previously been shown to have a damaging effect on health. The latest findings suggest that sustained exposure to underground railways – such as by regular commuting or working below-ground – could also have health implications.
However, little research has so far been carried out on the effects of working in an underground railway environment, which may also be rich in airborne metals.
Smaller than PM10 and PM2.5, comparatively little is known about the chemistry of ultrafine PM0.1 particles, but it does not typically pose such a risk to health, the study authors said.
So, why are these metal particles potentially dangerous? According to the authors, ultrafine particles can reach the deepest areas of the lungs – the alveoli – where oxygen enters the blood and waste gases leave to be exhaled. And, according to the study, there is evidence that ultrafine dust may be able to evade the protective barrier lining the airways to enter circulation. This means that ultrafine particles may not just impact the airways but also the cardiovascular system, liver, brain and kidneys.
Loxham said, “These tiny dust particles have the potential to penetrate the lungs and the body more easily, posing a risk to someone’s health.”
As a result of the study’s findings, Loxham has called for further research into the health impacts of particulate matter at underground railways.
He said: “Underground rail travel is used by great numbers of people in large cities all over the world.”
“The high level of mechanical activity in underground railways, along with very high temperatures is key in the generation of this metal-rich dust, and the number of people likely to be exposed means that more studies into the effects of particulate matter in the underground railway environment are needed, as well as examining how the levels of dust and duration of exposure might translate to effects on health.”
These are the findings of a University of Southampton study, ‘Physicochemical Characterisation of Airborne Particulate Matter at a Mainline Underground Railway Station’, published in the Environmental Science and Technology journal on April 16 and funded through the Integrative Toxicology Training Partnership studentship provided by the Medical Research Council UK.