Around seven million premature deaths globally each year are linked to air pollution. Diesel exhaust has long been identified as a key culprit. However, new research suggests brake dust could be even more harmful to our lungs.
Dust from road wear, tyres, and brakes is referred to as “non-exhaust emissions.” It is now the primary type of pollution from road transport in many European countries. Of these, brake dust is the leading contributor, yet it remains unregulated.
BRAKE DUST VS. DIESEL EXHAUST: A LAB COMPARISON
In a study, the researchers exposed lung-like cells to both brake dust and diesel exhaust dust. Surprisingly, brake dust proved far more damaging across several indicators of lung diseases like cancer and asthma. Interestingly, removing copper from the brake dust reduced its harmful effects.
A CALL FOR NEW REGULATIONS
UK vehicle regulations focus on exhaust emissions. However, our research highlights the urgent need to regulate non-exhaust emissions. This is especially true for brake dust. Reformulating brake pads could help reduce the health burden of these pollutants.
THE ASBESTOS LINK AND NEW BRAKE PAD DESIGNS
Brake pads were once made with asbestos to manage overheating. Nevertheless, asbestos was banned in 1999 due to its harmful effects on the lungs. The motor industry quickly moved to non-asbestos organic (NAO) pads, which are now common in vehicles.
Ironically, the research revealed a surprising finding. Dust from NAO pads was the most toxic to lung cells. It surpassed even diesel exhaust dust in harmfulness.
TOXIC METALS IN BRAKE DUST
Brake dust contains metals, which are known to have toxic effects on health. Our analysis found that copper was a major component of brake dust from NAO pads. Copper was able to penetrate lung cells, and neutralizing it reduced its toxic impact. This suggests copper is a key factor in the harmful properties of brakedust.
THE HEALTH RISKS OF COPPER EXPOSURE
Studies show that nearly half of the copper in the air we breathe comes from brake and tyre wear. High concentrations of copper have been linked to impaired lung function and increased mortality risk.
Electric Vehicles Aren’t the Full Solution
While electric vehicles (EVs) eliminate exhaust emissions, they do not solve the problem of road, tyre, and brake dust. In fact, due to their heavier weight, EVs can generate more non-exhaust dust than traditional petrol or diesel vehicles.
EVs may feature regenerative braking systems, which help reduce wear on brakes. However, EVs still rely on traditional friction brakes. This reliance generates brakedust in the process.
NEW EMISSION STANDARDS AND FUTURE INNOVATION
The Euro 7 emissions standards, set to take effect in 2026, will target brakedust emissions. This may encourage the development of new brake materials. It could also lead to dust-trapping technologies. Additionally, it might prompt changes in road design to reduce dust emissions.
In the US, both California and Washington have already passed laws to reduce copper content in brake pads. While this was primarily driven by concerns about the environmental impact of copper runoff, it also addresses the health risks posed by brakedust.
NON-EXHAUST EMISSIONS: THE OVERLOOKED DANGER
Non-exhaust emissions now account for around 60% of vehicle-derived pollution in the UK. It is essential to recognize that there is no safe level of exposure to any air pollutant. As we transition to electric vehicles, it is crucial that science and regulation focus on non-exhaust emissions just as much as exhaust emissions.
