Exposure to air pollution is a significant global issue that is linked to approximately seven million premature deaths each year. While diesel exhaust emissions have long been identified as a major contributor to urban air pollution, recent research suggests that dust from brake pads may be even more harmful to our lungs.
According to a study published in Particle and Fibre Toxicology, non-exhaust emissions, including dust from road wear, tyres, and brakes, have now surpassed exhaust emissions as the primary type of emissions from road transport in many European countries. Brake dust, in particular, is a major source of these emissions, yet it is not currently regulated.
Researchers conducted experiments using lab-grown cells that mimic the lining of the lung and exposed these cells to both brake dust and diesel exhaust dust. The results showed that brake dust was significantly more harmful to the cells, with effects linked to lung diseases such as cancer and asthma. Interestingly, removing copper from the brake dust reduced these harmful effects, suggesting that copper may play a key role in the toxicity of the dust.
Current vehicle regulations in the UK only target exhaust emissions, highlighting the need for regulations on non-exhaust emissions such as brake dust. The study also compared the toxic effects of dust from different types of brake pads, revealing that non-asbestos organic (NAO) pads, commonly used in vehicles today, were the most toxic to lung cells.
The high copper content in brake dust was identified as a key factor in its toxicity, with AI techniques showing that copper could penetrate lung cells. Treating the brake dust with a copper-neutralizing chemical reduced its harmful effects, indicating the role of copper in the toxicity of the dust.
As the world transitions to electric vehicles (EVs) to reduce exhaust emissions, it’s important to note that EVs still generate non-exhaust dust from road, tyre, and brake wear. Studies suggest that EVs may generate more non-exhaust dust than petrol or diesel vehicles due to their weight. While some EVs are equipped with regenerative braking systems, they still rely on friction braking systems that produce brake dust.
The upcoming Euro 7 emissions standards will place limits on brake dust emissions, driving innovation in brake materials and dust-trapping mechanisms. It may also encourage improvements in traffic calming and road design to reduce brake dust emissions.
Overall, the study emphasizes the importance of addressing non-exhaust emissions, such as brake dust, as seriously as exhaust emissions. As regulations evolve and new technologies are developed, it is crucial to consider the health impacts of all types of air pollution and work towards creating a cleaner and safer environment for all.
