Key Takeaways:
- Brake dust is more harmful to lung cells than diesel exhaust as it increases oxidative stress and inflammation.
- Brake pads containing copper cause the highest cellular damage, disrupting metabolism and triggering pathways linked to lung disease.
- Unlike fuel emissions, brake dust remains largely unregulated despite its health risks.
- Reducing or eliminating copper in brake pads can significantly lower their toxicity.
- Some U.S. states, like California and Washington, have begun regulating copper in brake pads, primarily to protect waterways but with potential lung health benefits.
Brake Dust from Cars May Be Highly Harmful to the Lungs
By potentially triggering more inflammation and cellular stress, brake pad dust could be more damaging to human lung cells than diesel exhaust fumes.
As cities worldwide crackdown on emissions from gasoline and diesel vehicles, a more insidious form of air pollution has quietly emerged alongside increased traffic: brake pad dust. In a recent study, researchers from the University of Southampton (UK) examined the effects of fine particulate matter (PM2.5) released during braking, which remains suspended in the air, can reach the alveolar regions of the lungs, and is linked to more than 4 million premature deaths globally each year. This source of pollution remains “unregulated” for now.
Inflammation and Oxidative Stress: Brake Dust Disrupts Cellular Homeostasis
For the study, published in Particle and Fibre Toxicology, the research team cultivated lung cells in a laboratory setting to simulate the lung lining and exposed them to both brake dust—some asbestos-free but containing copper—and diesel exhaust particles. “We used RNA sequencing to analyze global transcriptomic changes, metabolic analyses to study glycolytic reprogramming, and mass spectrometry to determine particle composition,” the study explains.
The results showed that brake dust was significantly more harmful to lung cells than diesel exhaust fumes. Specifically, particles generated by the wear of asbestos-free but copper-containing brakes induced the highest levels of oxidative stress, inflammation, and “pseudohypoxic HIF activation”—a pathway associated with diseases linked to air pollution exposure, including cancer and pulmonary fibrosis. Additionally, brake dust disrupted metabolism more severely compared to wear particles from low-metal or semi-metallic brake pads. When researchers treated the brake dust with a chemical to neutralize copper, its toxic effects were mitigated.
The Need for Targeted Legislation to Protect Public Lung Health
Given these findings, scientists stress the urgent need to regulate non-exhaust emissions as well. “New brake pad formulations could reduce overall dust emissions or be designed to exclude toxic components, similar to the past removal of asbestos. In the United States, California and Washington State have enacted legislation to reduce the copper content in brake pads though this measure was primarily introduced due to concerns about copper runoff from brake dust contaminating waterways and harming aquatic life,” they explained.
Related Reading:
Living in a Polluted Area Affects Cardiovascular Health
Air Pollution in Cities Responsible for Nearly Two Million Excess Deaths Worldwide Annually
Half of the Us Population Born before 1996 Lost on Average 3 IQ Points Due to Exhaust Fumes
FAQs on Brake dust health risks
How does brake dust affect the lungs?
It triggers inflammation, oxidative stress, and metabolic disruptions, leading to potential lung diseases.
Why is brake dust more harmful than diesel fumes?
It contains fine particulate matter with metals like copper, which causes higher cellular damage.
Are all brake pads equally toxic?
No, copper-containing brake pads are the most harmful, while low-metal and semi-metallic pads have less impact.
Can regulations help reduce brake dust toxicity?
Yes, limiting toxic metals in brake pads can reduce health risks.
Which states have acted on brake dust regulations?
California and Washington have restricted copper in brake pads to protect the environment.
What can individuals do to minimize exposure?
Use high-quality, low-metal brake pads and avoid prolonged exposure to traffic pollution.
References
Parkin, J. G. H., Dean, L. S. N., Bell, J. A., Easton, N. H. C., Edgeway, L. J., Cooper, M. J., Ridley, R., Conforti, F., Wang, S., Yao, L., Li, J., Raj, H. V., Downward, J., Gerlofs-Nijland, M., Cassee, F. R., Wang, Y., Cook, R. B., Jones, M. G., Davies, D. E., & Loxham, M. (2025). Copper-enriched automotive brake wear particles perturb human alveolar cellular homeostasis. Particle and Fibre Toxicology, 22(1), 4. https://doi.org/10.1186/s12989-024-00617-2
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