Car emissions contain various pollutants that can have negative impacts on the environment and human health. However, recent research has found that a substance produced by cars is even more harmful to human health than the toxic emissions in exhaust gases.
Researchers James Parkin and Professor Matt Loxham from the University of Southampton in the UK revealed in an article on The Conversation website that approximately 7 million people worldwide die prematurely each year due to air pollution.
While car exhaust emissions are typically seen as the main culprit, previous studies have shown that dust from brake pads is even more toxic than car exhaust emissions, posing greater harm to people’s lungs.
The dust generated from the wear and tear of roads, tires, and brake pads, known as “non-exhaust emissions,” has become a major source of pollution from road transport, surpassing exhaust emissions in many European countries.
In particular, brake pad dust is often a primary factor but has not been regulated. Compared to car exhaust emissions, people are much less aware of the potential health impacts of brake pad dust.
The researchers conducted experiments in which they cultured cells in the laboratory to simulate lung walls and exposed these cells to dust from brake pads and diesel engine exhaust, for comparison. The results showed that brake pad dust posed a greater risk to these cells in terms of lung diseases such as cancer and asthma, compared to exhaust dust.
The researchers emphasized the need for governments to regulate non-exhaust emissions. They suggested that redesigning brake pads could be a way to reduce the potential health burden caused by these emissions.
Previously, brake pads contained asbestos fibers to address overheating issues. However, due to the health risks associated with asbestos, its use was banned in the UK in 1999. This led to the development of new brake pads, such as the commonly used non-asbestos organic (NAO) brake pads in current vehicles.
Comparing the harm caused by dust generated from different types of brake pads, it was discovered that NAO brake pads produced the most toxic dust to lung cells, compared to other types of brake pads and diesel engine exhaust dust. Contact with this dust could lead to diseases like lung cancer, fibrosis, asthma, and chronic obstructive pulmonary disease.
The researchers found that NAO brake pads have high copper content, which can enter affected lung cells. By neutralizing the copper in brake pad dust with chemical treatment, its toxicity can be reduced, indicating the harmful nature of copper in this dust.
They highlighted that nearly half of the copper present in the air people breathe comes from brake pad and tire wear. Studies have also shown that exposure to high concentrations of copper is associated with impaired lung function and increased risk of overall mortality.
As for electric vehicles, there have been studies indicating that due to their weight, they produce more non-exhaust emissions compared to fuel cars, debunking the notion of zero emissions. While some electric vehicles come equipped with regenerative braking systems to assist in slowing down the vehicle, they still generate brake pad dust using friction-based braking systems.
The researchers mentioned that the introduction of the Euro 7 vehicle emission standards in November 2026 by the EU will restrict brake pad dust emissions, possibly leading to the development of new brake materials or mechanisms to prevent dust leakage.
Furthermore, this could prompt governments to focus more on easing traffic congestion and road design to reduce instances of idle stops and aggressive driving, both of which contribute to brake pad dust emissions.
In conclusion, the development of new methods of brake pad production may reduce dust emissions or be designed to exclude toxic components, similar to the banning of asbestos. For example, in the US, states like California and Washington have passed legislation to reduce copper content in brake pads.
The researchers stressed that non-exhaust emissions are prevalent, constituting around 60% of all pollution particles produced by cars in the UK. It is crucial for people to realize that no amount of air pollution is safe. As the shift from fuel-powered cars to electric vehicles continues, the scientific community and regulatory bodies must address brake pad dust emissions with the same seriousness as exhaust emissions.