Brake Dust Poses Greater Health Risks Than Diesel Exhaust, Study Warns

The World Health Organisation estimated that exposure to indoor and outdoor air pollution is associated with around 7 million premature deaths yearly. Globally, air pollution is the ultimate environmental risk factor for mortality and morbidity. According to a study by the University of Southampton, dust from car brakes (Dust- particulate matter from brake pads-PM) could cause more damage to our respiratory systems than diesel cars that we are driving.

The key air pollutant is particulate matter (PM).

What is this Particulate matter? 

It is a complex mixture of particles and liquid droplets that are suspended in the air and have diverse physical and chemical properties. 

The primary site for particulate matter deposition is the lungs. A fine particulate matter which is around aerodynamic diameter < 2.5 µm can deposit in the bronchioles and the alveoli and some particles are small enough to translocate into the bloodstream and provoke systemic effects.

Taking into consideration all air pollutants, exposure to fine particulate matter has been associated with a big impact on human life expectancy as well as all-cause and cause-specific mortality.

The research team have exposed lung cells to fine particulate matter of four types of brake pads:

1. Non-asbestos organic

2. Hybrid-ceramic

3. Low metallic 

4. Semi-metallic. 

The recent study identified that particulate matter from copper-enriched non-asbestos organic, and ceramic brake pads induces the greatest oxidative stress, inflammation, and pseudo-hypoxic HIF activation as well as perturbation of metabolism, and metal homeostasis compared with brake wear particulate matter from low- or semi-metallic-pads, and also, notably, diesel exhaust particulate matter.

(A pseudo-hypoxic HIF activation is a pathway implicated in diseases associated with air pollution exposure, including cancer, and pulmonary fibrosis. Here the lung cells react as if there is deprivation of oxygen despite oxygen being present.).

Non-asbestos organic and hybrid-ceramic have proved the most potent inducing significant markers of toxicity. Since both contain copper, the researchers have removed the copper element and checked the toxicity levels, which have diminished.

This new research indicated that limiting copper in brake pads may also have incredible benefits for human health.

Some US states, such as California and Washington, have already raised restrictions on copper in brake pads. Yet, these regulations were originally intended to protect aquatic life, as copper from road runoff can be harmful to fish.

Dr. James Parkin, lead author, said “People normally associate pollution from cars as being from exhaust pipes and believe that electric vehicles (EVs) have zero emissions. However, EVs do produce particulate matter due to friction and wear of the road, tyres, and brakes.”

The research study findings have depicted the importance of Particulate matter composition that could cause potential health effects and also highlight the need for targeted legislation to protect public health.

Recently BHP News put a note on this matter, mentioning that it should not lead to ban brakes as brake dust accumulated depends on the alloy wheel design. 

“ It depends on brake pad friction material. Organic pads emit less dust, Semi-metallic pads emit heavy dust While Ceramic pads and Ceramic-Organic hybrid pads dust the least. Generally, heavy cars come with semi-metallic pads which can cause the alloys to go dark in a matter of a few hundred km. Neighbour's XUV7OO alloys and brake callipers are baked in brake dust. Not very sure whether he uses original pads or aftermarket.”

There are available after-market pads that will dust less. One needs to explore a bit and understand.

References:

1. Parkin, J.G.H., L.S.N. Dean, J.A. Bell, et al. "Copper-Enriched Automotive Brake Wear Particles Perturb Human Alveolar Cellular Homeostasis." Particle and Fibre Toxicology 22, no. 4 (2025). https://doi.org/10.1186/s12989-024-00617-2.

2. Iyer, Ananth. "Research Indicates Brake Dust Could Be More Harmful Than Diesel Fumes." Team-BHP.com, February 22, 2025. https://www.team-bhp.com/news/research-indicates-brake-dust-could-be-more-harmful-diesel-fumes.

(Input from various sources)

(Rehash/Dr. Lakshmisahithi Tanneru/MSM)