The London Underground is polluted with METALLIC particles small enough to enter the bloodstream

Every day, more than five million Londoners board the London Underground on their daily commute.

But if you take the subway to work, you might be looking at alternative modes of transportation, according to a new study.

Scientists from the University of Cambridge warn that the London Underground is polluted with ultrafine metal particles small enough to enter the human bloodstream.

The particles found are so small they’re unlikely to be picked up by pollution surveys — and scientists still don’t know what health risk they might pose.

A new study from the University of Cambridge has revealed that London Underground is polluted with ultrafine metal particles small enough to enter the human bloodstream – but they are unsure what the risks are to people’s health represents

Researchers found pollution particles in some of London’s busiest underground stations and on carriages. Their diameters ranged from five nanometers to 500 nanometers. Pictured: An image of an oxidized nanoparticle

While it was already known that 50 percent of the particles on the tube were iron, the new research found samples contained particularly high concentrations of a type of iron oxide called maghemite.

Other particles measured were 500 nanometers in diameter, with the average diameter being 10 nanometers wide.

Pipe wheels, chains and brakes are all to blame for tiny iron-rich particles being flung up when they rub against one another.

Iron takes a long time to oxidize and turn into maghemite, meaning this pollution has been stuck in the world’s oldest subway system for years.

The reason for this lies in the poor ventilation of the entire subway, especially on the platforms.

Cabins on the Piccadilly, Northern, Central, Bakerloo, Victoria, Northern, District and Jubilee routes were sampled between 2019 and 2021

In the study, the scientists took dust samples from ticket halls, platforms and tube wagons to assess the extent of pollution.

Cabins on the Piccadilly, Northern, Central, Bakerloo, Victoria, Northern, District and Jubilee routes were sampled between 2019 and 2021.

Large stations such as King’s Cross, St Pancras, Paddington and Oxford Circus were also sampled.

While several studies have been conducted in the past to monitor underground pollution levels, this is the first time that the size and nature of the pollutants have been analyzed in depth.

There is no immediate solution to the problem, but researchers have suggested that regularly removing dust from underground tunnels and magnetically monitoring pollution levels could significantly improve air quality.

A range of different particles found on the London Underground. Researchers took samples from subway cars and ticket stations to analyze pollution levels in depth. Pictured: Samples from the London Underground

Washing tracks and tunnel walls and installing screen doors between platforms and trains could also be a solution to the problem.

Pollution levels in London, and particularly on the Tube, are higher than the limits set by the World Health Organization (WHO).

Currently, these levels are measured by air filters and do not detect what types of particles are floating around.

Hassan Sheikh, lead author of the report from Cambridge’s Department of Earth Sciences, said: “I started studying environmental magnetism as part of my PhD, investigating whether low-cost monitoring techniques could be used to characterize pollution levels and sources.

“The subsurface is a well-defined microenvironment, so it’s an ideal place to conduct this type of study.”

Although the study didn’t address the health effects of these small particles, it paved the way for further research.

Mr. Sheikh continued: “The abundance of these very fine particles was surprising.

“The magnetic properties of iron oxides change fundamentally when the particle size changes. Furthermore, the scale at which these changes occur is the same at which air pollution becomes a health hazard.

“In order to answer the question of whether these particles are harmful to health, you first have to know what the particles are made of and what properties they have.”

There is no immediate solution to the problem, but researchers have suggested that regularly removing dust from underground tunnels and magnetically monitoring pollution levels could significantly improve air quality

Pollution levels in London, and particularly on the Tube, are higher than the limits set by the World Health Organization (WHO).

Commenting on the research findings, Zongbo Shi, Professor of Atmospheric Biogeochemistry at the University of Birmingham, said: “It is already known that particulate matter pollution in the London Underground is extremely high and this research further confirms that many of the particles originate from abrasion and contain iron.

“Iron oxides are likely to cause oxidative stress and therefore pose a potentially high health risk.

“This is high-quality research and provides further evidence of the need to develop interventions to reduce passenger exposure to airborne particles and improve health.”

The research was supported by the European Union, the Cambridge Trust and Selwyn College, Cambridge.

If you liked this article…

How clean is your indoor air REALLY? MailOnline tests quality inside McDonald’s, Wetherspoons and the London Underground – with levels of pollution FIVE times higher than outside air in some places

The London subway is more polluted than the New York subway and the Beijing subway, new research shows

How polluted is the air where you live? Shocking interactive tool reveals how 97% of UK addresses now exceed at least one toxic pollutant limit