Prioritize tackling toxic emissions from tires, experts urge

Experts from Imperial College London are calling for more to be done to limit the potentially harmful effects on health and the environment of toxic tire particles.

Researchers at Imperial College London’s Transition to Zero Pollution initiative warn that while electric vehicles will eliminate the problem of fuel emissions, we will continue to have a problem with particulate matter from tire wear.

Six million tonnes of tire debris are released each year worldwide, and in London alone 2.6 million vehicles emit around 9,000 tonnes of tire debris annually.

Despite this, research on the environmental and health impacts of tire wear has been neglected compared to research and innovation to combat fuel emissions. Imperial researchers say the impact of new technologies on the origin and impact of tire wear should be a priority.

In a new briefing, a multidisciplinary group of Imperial experts, including engineers, ecologists, medics and air quality analysts, call for investing as much in tire wear research as in reducing fuel emissions — and understanding their interactions.

The lead author Dr. Zhengchu Tan of the Imperial Department of Mechanical Engineering said: “Tire debris pollutes the environment, the air we breathe, the water runoff from roads and [have] amplifying impacts on waterways and agriculture. Even if all of our vehicles eventually run on electricity instead of fossil fuels, we will still have harmful vehicle pollution due to tire wear.

“We call on policymakers and scientists to initiate ambitious research on tire debris pollution to fully understand and reduce its impact on biodiversity and health, and research to reduce the generation of these particles.”

Transition to Zero Pollution is an initiative by Imperial College London that aims to create new partnerships between research, industry and government to achieve a sustainable, pollution-free future.

Professor Mary Ryan, Vice Provost (Research and Enterprise) at Imperial College London and co-author of the briefing, said: “To protect our planet and the health of future generations, we need to look at not just an issue from a single perspective, but one system-level approach. Therefore, we need to look beyond carbon and consider man-made pollution in all its forms.

“Electric vehicles are a crucial step forward in decarbonizing transport, but we also need to look at the bigger picture. Some worry that EVs tend to be heavier, which could increase tire wear. This is precisely why Imperial College London is driving a holistic, connected approach to sustainability challenges.

“We will continue to use the full power of our research and influence to find meaningful solutions and help make a sustainable, green future a reality.”

In the briefing, the researchers discuss how tire wear leads to these particles, where the particles end up, the potential impact they have on people and the planet, and why we need to act now.

tire wear particles

When tires break, they release a range of particles, from visible bits of tire rubber to nanoparticles. Large particles are carried by rain from roads into rivers, where they can release toxic chemicals into the environment, while smaller particles become airborne and are inhaled. They are small enough to penetrate deep into the lungs.

These particles can contain a range of toxic chemicals including polyaromatic hydrocarbons, benzothiazoles, isoprene and heavy metals such as zinc and lead.

Impact on the environment

Particulate matter from tire debris is a significant source of “microplastics” in rivers and oceans, and tire debris in cities could pose up to four times the risk to the environment than other microplastics.

While existing technological interventions such as filters and environmental policies could help control our environmental footprint, there are major gaps in our knowledge, understanding and ability to predict the impact of tire abrasion pollution.

co-author dr. Will Pearse of the Imperial Department of Life Sciences said: “Tire debris does not naturally degrade but rather accumulates in the environment and can interact with other pollutants as well as biological organisms. Our understanding gaps are widening. Research and development of new solutions is essential so that we can limit all types of vehicle pollution.”

Health Effects

The impact of tire wear particles on human health is a growing concern, and the full long-term impact on our health urgently requires more research.

There is growing evidence that tire debris and other particulate matter can contribute to a range of adverse health effects, including cardiac, pulmonary, developmental, reproductive and cancer effects.

Co-author Professor Terry Tetley of Imperial’s National Heart and Lung Institute said: “We are increasingly concerned about the impact of tire wear on human health. Because some of these particles are so small that they can become airborne, it’s possible that just walking on the sidewalk could expose us to this type of pollution. It is important that we better understand the impact of these particles on our health.”

change gear

The researchers argue that reducing tire pollution should be seen as a key enabler for cleaner and more sustainable transport alongside reducing carbon emissions₂ and other exhaust emissions. In tackling the climate crisis, we should develop better systems and technologies to protect the environment; and research funding, government policies and regulatory frameworks should reflect this.

The report’s authors urge policymakers and scientists to examine the complex issues surrounding tire debris pollution, from understanding the fundamentals of how wear particles are formed to understanding how these particles affect the health of people and the planet. Potential innovation solutions include particle capture technologies, new advanced materials, and disruptive business models that drive other modes of transportation. These need to be linked to clear policy and regulation and to a broader discussion about urban transport systems.

The research effort, they say, should include:

• Establishment of standardized methods for measuring tire wear in the environment and its toxicity.
• Reducing damage to terrestrial and aquatic species and humans by tightening limits on the use of harmful components in tire materials.
• Start new experiments to better understand the short- and long-term effects of particles of different sizes on the environment and human health.
• Efforts to better understand the underlying mechanisms of wear and to propose strategies to reduce wear, such as