Brake Pad Dust is More Toxic Than Diesel: Study

A recent study by the University of Southampton has revealed that microscopic particles from brake pads may be more toxic than diesel exhaust emissions. The research raises concerns that even with the widespread adoption of electric vehicles (EVs), air pollution caused by non-exhaust emissions could still pose serious health risks.

Brake Dust

The study found that brake dust is now a leading contributor to vehicle-related air pollution in the UK and parts of Europe. Unlike exhaust emissions regulated under strict environmental laws, brake wear emissions remain largely unregulated despite their significant impact on air quality.

Scientists discovered that brake dust contains fine particulate matter (PM2.5 and smaller), which can penetrate deep into the lungs and increase the risk of respiratory and cardiovascular diseases. These harmful particles are released into the air when brakes are applied, affecting drivers and pedestrians.

Brake Pad Materials and Toxicity Levels

The research examined four different types of brake pad materials:

• Non-asbestos organic (NAO)
• Semi-metallic
• Hybrid-ceramic
• Low metallic

The results showed that non-asbestos organic (NAO) brake pads were the most toxic, causing severe inflammation and damage to human lung cells. Ceramic pads ranked as the second most harmful. The toxicity levels were largely linked to the high copper content found in these brake pads.

Electric Vehicles’ Contribution to Air Pollution

While electric vehicles (EVs) are often considered zero-emission, the study emphasizes that they still produce pollution through brake, tire, and road wear. Since EVs tend to be heavier than traditional petrol or diesel vehicles, they may even cause more brake wear, increasing the release of harmful particles into the air.

Dr. James Parkin, lead researcher of the study, pointed out that people often associate vehicle pollution only with exhaust emissions, assuming that EVs eliminate air pollution. However, brake wear emissions remain a major environmental concern, even in a fully electric vehicle future.

Stricter Regulations

Currently, vehicle emission laws focus mainly on exhaust pollution, ignoring non-exhaust sources like brake and tire wear. Researchers argue that this approach fails to address the growing health risks linked to brake dust pollution.

Prof. Matthew Loxham, project supervisor, suggests reducing copper levels in brake pads could help minimize toxicity. He also emphasized the need for updated policies to regulate vehicle-related air pollution.

The findings indicate that while EV adoption is a step forward for cleaner air, policymakers must also focus on non-exhaust emissions to ensure long-term public health and environmental benefits.