Tyre Particles and Electric Vehicles: A Climate Solution with a Pollution Challenge

Electric vehicles (EVs) are widely promoted as a solution to climate change due to their zero tailpipe emissions. However, recent research highlights a hidden downside: tyre particle pollution. As EVs become heavier and more common, the increased wear and tear of tyres releases a significant volume of microplastics and toxic substances into the environment. These particles, often overlooked in emissions assessments, pose serious risks to human health and ecological balance. This article explores the various dimensions of tyre particle pollution caused by EVs, their global impact, and how policy, technology, and public awareness can drive mitigation.

What are tyre particles and why are they a concern?

Electric vehicles (EVs) have been globally hailed as a crucial solution in the fight against climate change, especially for their ability to eliminate tailpipe greenhouse gas emissions. However, EVs come with a lesser-known downside — the generation of tyre wear particles (TWPs), a significant form of microplastic pollution. These particles are formed due to the regular degradation of tyres as vehicles move, brake, and accelerate.

TWPs are small plastic fragments resulting from the friction between tyres and road surfaces. They vary in size, with many falling into the PM2.5 or PM10 category, making them small enough to enter human lungs and even the bloodstream. Unlike tailpipe emissions, which have stringent global regulations, non-exhaust emissions like tyre and brake wear are not yet uniformly regulated, even though they contribute significantly to air and soil pollution.

Tyre particles are not just rubber; they are complex mixtures of synthetic polymers, natural rubber, heavy metals (especially zinc), and chemical additives like 6PPD — which can transform into the highly toxic compound 6PPD-quinone. These particles are found in soil, water systems, and air, and are often consumed by marine life and humans, posing risks to ecosystems and public health.

Key concerns include:

• Microplastic pollution in marine and terrestrial environments
• Toxicity to aquatic life, particularly salmon and microalgae
• Airborne particles that can cause respiratory and cardiovascular diseases
• Accumulation in human tissues, including lungs and blood

EVs, due to their higher weight from large battery packs, are especially prone to increased tyre wear, which leads to the disproportionate generation of TWPs when compared to lighter, internal combustion engine (ICE) vehicles.

Why do electric vehicles contribute more to tyre pollution?

While EVs are promoted for being tailpipe-emission free, their higher weight and instant torque result in accelerated tyre degradation. Several scientific studies — including one from Indian researchers published in Soft Matter and another by European researchers in Environmental Pollution — confirm that the mass and speed of EVs correlate directly with increased release of smaller plastic particles during tyre wear.

Here’s how EVs increase TWP pollution:

• Battery weight: EV batteries typically weigh between 300 kg to over 900 kg, increasing the overall weight of the vehicle by 15-30% compared to ICE vehicles.
• Increased torque: EVs accelerate quickly, which causes more friction and heat on the tyres, especially during urban driving conditions involving frequent start-stop movements.
• Structural reinforcement: Heavier batteries require sturdier vehicle frames, which adds to overall mass and tyre load.
• Primary fragmentation: Heavier vehicles cause micro-sized particles to be released more due to sudden braking, acceleration, and road potholes.

Unlike larger tyre particles that settle quickly, the smaller particles remain airborne, significantly affecting urban air quality. While regenerative braking in EVs reduces brake wear pollution, this benefit is offset by the increased tyre wear, making TWPs a leading form of non-exhaust vehicular emissions in cities.

Where are tyre particles accumulating globally?

Tyre wear particles (TWPs) are now being detected across a wide range of environments — from urban roadsides and waterways to the remote snowfields of the Alps and polar regions. Their global distribution highlights their mobility, long-range atmospheric transport, and persistence in ecosystems. These particles settle in soil, air, stormwater systems, and ultimately reach rivers, lakes, and oceans. Research has also found TWPs in human urine, food, drinking water, and even breast milk, demonstrating their pervasive nature.

Key areas of TWP accumulation:

• Urban areas: Dense traffic and poor road conditions amplify the generation and deposition of TWPs. Cities like London, Milan, and Barcelona have reported high levels of non-exhaust emissions, especially near busy intersections.
• Roadside ditches: Studies in Sweden show that TWPs are found even 3 meters away from the road and deep into the soil, illustrating their ability to migrate vertically and horizontally.
• Water bodies: TWPs enter stormwater systems and are carried into streams, lakes, and oceans, where they become major sources of marine microplastic pollution.
• High-altitude and polar regions: Nanoplastic forms of TWPs have been detected in the Alps, Antarctica, and the Arctic, suggesting global dispersion via wind currents and precipitation.
• Food chain and human body: TWPs and their additives have been detected in fish, human tissues, and agricultural soils, indicating bioaccumulation and trophic transfer.

Notable observations:

• TWPs make up 28% of global microplastic pollution.
• In Europe, up to 78% of PM2.5 in urban areas comes from non-exhaust emissions, with tyre particles being a major contributor.
• Even well-maintained road networks are not immune; airborne TWPs can travel hundreds of kilometers before settling.
• The most contaminated soil layers are often those 0.1–0.3 meters deep, close to roads, with concentrations of up to 12.40 mg/kg.

This widespread accumulation challenges the assumption that TWPs are a localized issue. Their chemical resilience, varied particle sizes, and invisible nature make them a global environmental threat, affecting air, water, land, and biological life.

When did tyre pollution become a major concern?

Though tyre wear has been an issue since the invention of the automobile, its recognition as a major environmental hazard has only occurred over the last decade, especially with the rise of electric vehicles and increasing urbanization. The transition to EVs has pushed tyre pollution into the spotlight, as EVs eliminate tailpipe emissions but increase non-exhaust particulate pollution.

Timeline of key developments:

• Pre-2000s: TWPs were generally overlooked, classified under general road dust.
• 2010–2015: Initial studies began identifying microplastics in oceans. Tyre particles were not yet a distinct category.
• 2017: Estimates by Kole et al. showed 6 million tonnes of TWPs are released annually.
• 2020 onwards: Major studies like those by Baensch-Baltruschat, Adamiec, and Järlskog confirmed TWPs as a leading source of microplastics and toxic metals.
• 2023: Cities like London began monitoring non-exhaust emissions formally. Global treaties started discussing plastic pollution, with rising calls to separate tyre particles as a distinct category.
• 2024–2025: Studies from India, Sweden, and South Korea revealed detailed mechanisms of tyre wear, particle size distribution, and their toxic impacts. Euro 7 regulations were proposed to include limits on brake and tyre emissions by 2026 and 2028, respectively.

Presently, tyre pollution is receiving more attention due to:

• Increasing EV adoption
• Discovery of toxic tyre additives like 6PPD-quinone
• Nanoplastic research showing particles can penetrate human cells
• Public health data linking airborne PM2.5 from TWPs to asthma, stroke, and heart disease
• Ongoing negotiations for a global plastic pollution treaty, though TWPs are still marginally discussed

Despite decades of vehicular research, the impact of non-exhaust emissions like TWPs has been underestimated. Only recently have we begun to grasp the magnitude and toxicity of this form of pollution. The urgency to regulate TWPs stems from both their scale and stealth, requiring swift action in the coming years.

Who is responsible for addressing tyre particle pollution?

Addressing the complex issue of tyre particle pollution requires a multi-stakeholder approach involving governments, manufacturers, scientists, and the general public. No single actor can tackle the problem alone due to the interdisciplinary nature of TWPs — spanning environmental science, public health, vehicle design, and urban infrastructure.

Key stakeholders and their responsibilities include:

• Governments and regulators:
  • Implement emission standards for non-exhaust pollutants, such as those under the upcoming Euro 7 regulations.
  • Fund scientific research and monitoring programs to quantify TWP pollution.
  • Create public awareness campaigns about tyre pollution’s health impacts.
  • Offer incentives for eco-friendly tyre innovations.
  • Support urban policies that reduce car dependency through public transport and infrastructure upgrades.
• Automobile manufacturers:
  • Redesign EVs to be lighter, using lightweight alloys and composite materials.
  • Integrate regenerative braking systems to reduce tyre stress and brake dust.
  • Use smoother acceleration algorithms to reduce tyre spin and particle emission.
  • Partner with tyre companies to develop vehicle-specific tyres optimized for weight and torque.
• Tyre manufacturers:
  • Develop durable, low-emission tyre compounds using sustainable, non-toxic materials.
  • Replace additives like 6PPD with safer alternatives.
  • Innovate airless or modular tyres that last longer and produce fewer particles.
  • Be more transparent about the chemical composition of tyres, enabling better toxicity assessments.
• Researchers and environmental agencies:
  • Study distribution, toxicity, and transport of TWPs in various ecosystems.
  • Innovate analytical methods for real-time detection of micro- and nanoplastics.
  • Investigate biodegradability and bioaccumulation of tyre-derived chemicals.
• International bodies:
  • Recognize TWPs as a distinct category of pollution, separate from traditional microplastics.
  • Create global monitoring networks like the Global Atmospheric Plastics Survey.
  • Establish a UN panel similar to IPCC or IPBES for microplastic and chemical pollution.
  • Coordinate data sharing and harmonized regulations across countries.
• Consumers:
  • Adopt eco-conscious driving habits — avoid rapid acceleration and sharp braking.
  • Prefer public transport, walking, or cycling when possible.
  • Choose vehicles with lower curb weight or those fitted with eco-tyres.
  • Demand corporate accountability and transparent labelling of tyre contents.

The responsibility is collective — regulators must set the direction, industries must innovate, and individuals must adapt. Delayed action may lead to irreversible damage, especially as EV adoption scales rapidly worldwide.

How are tyre particles released and transported?

Tyre particles are primarily released through the frictional interaction of the tyre with road surfaces during driving. This includes routine activities such as braking, cornering, acceleration, and driving over rough terrain or potholes. The weight and speed of the vehicle, road conditions, and driving style significantly influence the quantity and size of the particles generated.

Mechanisms of release:

• Primary fragmentation: Caused by abrupt movements like sudden braking, pothole impact, or acceleration. Releases a wide range of particle sizes, mostly smaller than 10 microns. These are more likely to remain suspended in air.
• Sequential fragmentation: Happens due to gradual wear and tear over time, generating larger particles (>100 microns) that settle quickly and accumulate in roadside soil and stormwater systems.

Once released, tyre particles follow multiple transport pathways:

• Airborne transport: Fine particles (PM2.5, PM10) can remain suspended for days, travelling long distances with wind. Studies have shown nanoplastics from tyres reaching remote mountain ranges and the poles.
• Runoff transport: Rain washes TWPs into stormwater drains, which then flow into rivers and oceans. Road design, slope, and presence of gully pots or bioswales affect this flow.
• Soil accumulation: In road ditches, TWPs infiltrate up to 0.5 meters deep. Factors like soil porosity, vegetation, and de-icing salt influence penetration.
• Leaching and chemical dispersion: Additives like zinc and 6PPD leach from TWPs into water or soil, increasing chemical toxicity beyond physical particle pollution.
• Biological ingestion: Micro- and nano-sized TWPs can be ingested by earthworms, plankton, fish, and eventually enter the human food chain.

Transport dynamics depend on:

• Particle size and density: Smaller, lighter particles are more mobile.
• Environmental conditions: Wind speed, rainfall, soil type, microbial activity, and pH affect fate and mobility.
• Infrastructure design: The presence of green infrastructure like rain gardens or permeable pavements can intercept TWPs before they reach water bodies.

TWPs are not static — they interact with soil minerals, organic matter, and other pollutants, forming complex chemical cocktails. This makes predicting their ecotoxicological impact challenging and underscores the importance of targeted mitigation strategies at the point of release.

What is the significance of tyre particle pollution?

The significance of tyre wear particle (TWP) pollution lies in its widespread environmental presence, its chemical complexity, and its adverse effects on ecosystems and human health. Unlike tailpipe emissions, which are steadily declining due to stringent regulations and the rise of electric vehicles, non-exhaust emissions like tyre and brake wear are not just increasing — they are becoming the dominant source of particulate pollution in urban environments.

Major reasons why TWPs are highly significant:

• Largest contributor to microplastics: TWPs contribute to 28% of global microplastic pollution, more than any other single source, including packaging waste and textile fibres.
• Invisible yet pervasive: These particles are not visible to the naked eye, making them difficult to detect and regulate. Yet they are found in air, soil, water, food, and the human body.
• Health risks: Particles, especially PM2.5, can enter the lungs, bloodstream, and even brain tissue. They are associated with respiratory, cardiovascular, reproductive, and neurological disorders.
• Aquatic toxicity: Additives like 6PPD-quinone are lethal to aquatic organisms, including species like coho salmon. Even trace concentrations can disrupt ecosystems.
• Food chain entry: TWPs enter through soil, crop uptake, and water systems, eventually accumulating in livestock, fish, and humans.
• Climate impact: While not greenhouse gases themselves, TWPs can affect climate indirectly by altering soil microbiomes, reducing carbon sequestration, and adding heat-absorbing particulates to urban air.
• Urban pollution dominance: In many cities, up to 88% of PM10 now comes from non-exhaust sources like TWPs and brake dust. These particles remain largely unregulated.
• Rapid EV growth: With EVs accounting for 20% of global new car sales, and being 15-30% heavier than ICE vehicles, TWP emissions are set to rise, even as tailpipe emissions drop.

The problem is compounded by the fact that current regulatory frameworks are tailored to exhaust pollution, leaving a regulatory vacuum for TWPs. Their significance lies not just in their scale, but in their insidious nature — pervasive, unregulated, and chemically potent.

What are the limitations of current understanding and response?

Despite the growing awareness of tyre particle pollution, current responses are insufficient and fragmented. Several scientific, technological, and policy-related limitations hinder effective mitigation and regulation.

Key limitations include:

• Lack of classification: TWPs are often grouped under generic microplastics, which obscures their unique properties and health impacts. Experts now advocate treating them as a separate category of pollution.
• Limited regulation: While the Euro 7 standards will regulate brake emissions by 2026 and tyre emissions by 2028, they will only apply to new vehicles, and enforcement will take years to mature.
• Slow policy response: Most countries lack national frameworks to measure or regulate non-exhaust emissions. Air quality standards often focus only on PM2.5 and PM10, ignoring smaller nanoparticles that TWPs often fall into.
• Poor public awareness: Unlike exhaust pollution, tyre wear is not widely known to the public. Few understand that driving behavior, vehicle choice, and road design influence TWP generation.
• Insufficient scientific data: We still lack comprehensive data on:
  • Long-term toxicity of TWPs and their chemical additives
  • Dispersion patterns in different ecosystems
  • Synergistic effects with other pollutants
• Challenges in detection: Most TWPs are <500 μm, making them hard to sample. High-precision techniques like PYR-GC/MS or TED-GC/MS are expensive and not widely available.
• Industry opacity: Tyre manufacturers often withhold chemical formulations due to proprietary concerns, making toxicity studies difficult and inconsistent.
• Ineffective mitigation: Current stormwater systems, road sweeps, and urban planning do little to intercept TWPs. Capture technologies, like electrostatic collectors, are still in prototype phases.

Scientific journals, environmental watchdogs, and global agencies are calling for:

• Standardized measurement protocols
• Mandatory chemical disclosure by tyre companies
• Global treaties recognizing TWPs as distinct pollutants
• Interdisciplinary research into ecotoxicology and human health impacts

In short, despite rising data and concern, the world is years behind where it needs to be in terms of controlling and understanding tyre particle pollution. The limitations span across science, policy, industry, and public engagement, making this an urgent and multifaceted challenge.

What are the key challenges in mitigating tyre particle pollution?

Efforts to mitigate tyre wear particle (TWP) pollution face numerous challenges that are scientific, infrastructural, economic, and regulatory in nature. These hurdles complicate both the understanding of TWPs and the implementation of effective solutions.

Key challenges include:

• Invisibility and complexity of TWPs:
  • TWPs are often microscopic and chemically diverse, consisting of synthetic rubber, heavy metals, and various chemical additives.
  • Their small size (<10 µm) makes them hard to track, regulate, or intercept using conventional pollution control systems.
• Lack of global standards:
  • There is no universal methodology for measuring, classifying, or monitoring TWPs.
  • Many national air quality standards do not account for non-exhaust emissions, leading to significant regulatory blind spots.
• Rapid growth of EVs:
  • As EV adoption accelerates, so will the volume of tyre wear, given the increased weight and torque of electric vehicles.
  • EV tyres wear out 20-50% faster, creating more TWPs despite the reduction in tailpipe emissions.
• Tyre design limitations:
  • Tyres must balance grip, durability, fuel efficiency, and cost.
  • Innovations such as low-emission rubber compounds or airless tyres are still in experimental stages, with high production costs and limited commercial rollout.
• Opaque chemical composition:
  • Tyre manufacturers are not legally required to disclose the full list of chemicals used in tyre production.
  • This hinders toxicological studies, risk assessments, and regulatory efforts.
• Infrastructure inadequacies:
  • Most roads and urban infrastructure are not designed to intercept or manage TWPs.
  • Stormwater systems, especially in developing countries, often carry these particles directly into rivers and seas.
• Limited consumer awareness:
  • Drivers are largely unaware that driving styles—such as hard braking and rapid acceleration—directly influence tyre wear.
  • There is also little public knowledge about the environmental and health dangers of tyre-derived microplastics.
• Trade-off risks with technical fixes:
  • Low-wear tyre materials may use more toxic additives, such as 6PPD, which converts to 6PPD-quinone—highly toxic to aquatic life.
  • Capturing devices may be costly, require frequent maintenance, or consume additional energy.

These challenges underline the multidimensional nature of TWP pollution. Addressing it requires not only innovation, but also cooperation between governments, industries, scientists, and consumers. Delay in overcoming these barriers could lock societies into an era of “clean tailpipes, dirty tyres”, undermining broader environmental progress.

What is the way forward to address the issue effectively?

Solving the issue of tyre wear particle pollution requires a comprehensive, coordinated strategy that combines technology, regulation, public behavior change, and global cooperation. It must address both the sources of pollution and the pathways through which TWPs spread into the environment.

The recommended way forward includes:

• Policy and regulatory frameworks:
  • Recognize TWPs as a distinct pollutant, separate from general microplastics, to enable focused action.
  • Expand air quality standards to include non-exhaust emissions, especially particles smaller than PM2.5.
  • Enforce chemical transparency from tyre manufacturers to allow for better public health and ecological risk evaluations.
  • Implement Euro 7 and similar global regulations targeting both brake and tyre emissions.
• Vehicle and tyre innovations:
  • Promote lightweight vehicle design, especially in EVs, to reduce overall tyre stress.
  • Incentivize the development of durable, low-emission tyres using sustainable materials like dandelion rubber or silica-based compounds.
  • Support regenerative braking systems in EVs to reduce abrupt tyre wear.
• Capture and filtration technologies:
  • Develop and deploy on-vehicle TWP collection systems, such as electrostatic or magnetic traps.
  • Invest in stormwater treatment systems like bioswales, rain gardens, and sediment capture devices to prevent runoff into waterways.
• Urban infrastructure upgrades:
  • Improve road surfaces to minimize pothole-induced tyre fragmentation.
  • Design urban layouts that support slow driving zones, public transport, and non-motorized transport like walking and cycling.
• Public engagement and behavioral change:
  • Run awareness campaigns educating drivers about gentle driving habits to reduce tyre shedding.
  • Encourage the use of public transport and carpooling, especially in urban centres.
  • Provide eco-ratings for tyres, similar to fuel economy ratings, to help consumers make informed choices.
• International collaboration:
  • Establish a global scientific panel on tyre pollution under UN or IPCC frameworks.
  • Promote shared research platforms, data transparency, and cross-border monitoring programs.
  • Align strategies with the ongoing global plastics treaty to ensure TWPs are included.

The way forward is clear: we must treat tyre pollution with the same seriousness as tailpipe emissions. It is no longer enough to focus on carbon neutrality alone. A sustainable transportation future requires addressing invisible pollutants like TWPs with equal urgency. Only a holistic, science-led, and policy-backed approach can secure cleaner air, healthier ecosystems, and safer cities for the generations ahead.

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Conclusion

Electric vehicles have rightfully earned their reputation as a cornerstone in the global shift toward decarbonised transport. However, their environmental benefits come with hidden costs — most notably, the growing crisis of tyre wear particle pollution. As EVs replace internal combustion engines, attention must shift from tailpipes to tyres. Addressing TWP pollution is not just an environmental issue; it is a matter of public health, ecological balance, and urban sustainability. With focused research, robust regulations, innovative design, and global cooperation, we can ensure that the path to a cleaner future is not clouded by microplastics. It’s time to reimagine mobility — not just emission-free, but pollution-free in every dimension.

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Practice Question: How does the increased adoption of electric vehicles complicate the issue of air pollution despite their tailpipe emission benefits? (250 words)