The London Underground is vital to the connectivity of the city, providing commuters with an efficient way to travel. However, it has come under scrutiny due to the presence of hazardous dust that may be affecting passengers and workers alike.
According to a report by the Committee on the Medical Effects of Air Pollutants, there is a lack of studies that could help determine the impact of exposure to these underground pollutants on our bodies, which is very worrying.
At the same time, it also mentions that particulate matter in the air can affect commuters’ and workers’ health, and because the London Underground is… well… underground, these dust particles tend to accumulate in greater quantities there. Above ground, the particulate matter is blown away by the wind, which is not the case here.
What’s even more concerning is that, in addition to there not being enough studies on the health impact of this dust, there’s also the fact that its composition is different from the pollution found on roads.
Therefore, before we can determine how hazardous the tube dust in the London Underground is, we need to first find out what it’s made of.
What is Tube Dust made of?
London Underground tube dust is mostly a result of non-exhaust emissions, released by the train as it travels along.
As train wheels are made of metal and move along a metal track, the non-exhaust emissions produced are metal particles, mostly iron oxide along with traces of other metals like chromium, manganese and copper.
In addition, the particulate matter also contains quartz, which is produced as the result of construction and maintenance work done in the tunnels.
These particles are thrown up into the air because of the wheels on the track as well as the movement of the trains. If you’ve ever been in the Underground, you would have seen the settled dust being disturbed as the train entered or left the station. However, the visible dust isn’t as dangerous as the invisible particles.
All fine and invisible particulate matter can be classified into two categories:
- Inhalable dust
- Respirable dust
Inhalable dust is made up of fine particles that can get into your nose and mouth as you breathe, and are then deposited on to your respiratory tract.
Respirable dust, on the other hand, is composed of ultra-fine particles that can get inside your lungs and enter the tiny air sacs within that absorb oxygen to help you breathe.
Unfortunately, tube dust contains more than 30 to 40 times the respirable dust than that on busy London roads. Of course, as mentioned previously, the composition of dust above ground is different from what’s generated below, but this doesn’t make tube dust any less dangerous.
Health Effects of the Different Materials in Tube Dust
Whilst the dangers of tube dust on regular commuters and people who work there aren’t completely clear, we do know how the individual components of this dust affect our lungs and other organs.
Here’s an overview.
How Metal Dust Affects Our Lungs
We’ve previously discussed how metal fumes and dust affect the human body in an older post. But, while drivers and station staff may not be exposed to as much metal dust or fumes as welders or metal workers (200µg/m3 vs 5 mg/m3 over eight hours), they do face the risk of cumulative effects over time.
Long-term exposure to respirable metal dust can lead to lung damage, causing diseases like Siderosis (also known as Welder’s Lung or Silver Polisher’s Lung) or lung cancer. These ultra-fine particles can also get in the bloodstream and affect other organs.
How Quartz Dust Affects Our Lungs
Quartz or silica dust is considered a major health hazard in the construction industry, as it’s found in a range of materials like stone, concrete and brick. When inhaled, it can get in the lungs to cause Silicosis, Chronic Obstructive Pulmonary Disease (COPD) and even lung cancer. Also, like respirable metal dust, silica dust too can affect organs, like the kidneys.
What is TfL doing to Fix This?
Fortunately, Transport for London (TfL) is commissioning new studies on the effects of tube dust. It is also putting certain measures in place to reduce the amount of dust generated. These are:
- Modifying trains to run on alternating current (AC) motors, instead of direct current (DC) which produce carbon dust through long-term degradation
- Introducing new braking systems to reduce wear on pads and discs
- Changing construction and repair methods, including isolating the area being repaired, so the dust doesn’t spread and using hydraulic splitters instead of jackhammers to reduce the amount of airborne dust
- Introducing better ventilation systems to remove the dust that would have otherwise collected
- Using methods to reduce the amount of dust pushed up into the air when trains go past, either by cleaning the tunnels with vacuums and brushes or by treating the worst-affected areas with solutions that make the dust clump up
- Investigating electrostatic filters that will attract and capture dust and metal particles, even though this solution might be expensive and, as a result, limited to the stations that are deep underground
At VODEX, we offer a wide variety of solutions to help reduce airborne dust and fumes in the workplace. As such, our building and construction extraction systems could help prevent dust from getting into your workers’ breathing zone and your own, when working with materials that generate silica dust.
Could our extraction solutions be used for the hazardous dust in the London Underground, both in the stations as well as train carriages? We’ll leave that for TfL to find out!
Of course, if you need extraction solutions for your workplace to keep your workers and yourself safe, please do get in touch.