EVs Are Sending Toxic Tire Particles into the Water, Soil, and Air

Electric vehicles, you might have heard, are miraculous. Just a sliver of new cars sold in the United States are EVs, but these machines have united a mishmash of people eager to move America away from gasoline. Environmental groups are all-in, and the federal government is offering hefty incentives to spur sales. Automakers now offer twice as many EV models as before the pandemic, and are pumping out endless commercials to promote them. “We believe in an all-electric future,” General Motors CEO Mary Barra said in an interview a few weeks ago. Even car enthusiasts are getting on board: YouTube offers endless videos of people racing their EVs.

Such enthusiasm is warranted. The urgency of climate change requires electrifying the 278 million personal vehicles plying American roadways as quickly as we can. After all, EVs are far more climate-friendly than equivalent gas-powered models because they eliminate the tailpipe emissions that warm the planet and pollute the air. Better yet, EVs are simply fun to drive: Most models are quicker and quieter than your average gas car.

But that is not the full story. EVs also produce emissions beyond what spews from their tailpipe. Like all cars, their tires are constantly rubbing against pavement, releasing particulates that float through the air and leach into waterways, damaging human health and wildlife. New EV models tend to be heavier and quicker—generating more particulates and deepening the danger. In other words, EVs have a tire-pollution problem, and one that is poised to get worse as America begins to adopt electric cars en masse. None of this is inevitable. EVs don’t need to be so massive and lightning-fast—these are choices that the auto industry has made. All of us will pay the price.

This pollution is the inevitable result of the tire wear that every car owner experiences over time. Composed of hundreds of ingredients that can include natural and artificial rubber, petroleum, nylon, and steel, tires constantly spit out tiny bits of material, much of it invisible to the naked eye. The rate at which your tires break down will depend on many factors, but the cumulative quantity of tire pollution, ranging from visible pieces of rubber to nanoparticles, is staggering: as much as 6 million metric tons annually worldwide, according to a report from Imperial College London. “We are generating an enormous amount of rubber wear that ends up in the atmosphere as very small particles or on the road surfaces as large particles that get washed away,” Marc Masen, a mechanical engineer at Imperial College and a co-author of that report, told me. Rougher surfaces tend to produce larger tire chunks that settle on the ground, while smoother roadways, such as freshly paved highways, generate minuscule ones that can float in the air for hundreds of feet.

Much about tire pollution is still unknown. Compared with tailpipe emissions, tire particles are more difficult to measure in a laboratory and to isolate in the real world, where various kinds of car pollution mix together, Masen said. Only in recent years has the toll started to come into view. As a form of microplastics, tire pollution hits wildlife hard: Compounds that settle on the ground gradually leach toxic chemicals into the soil and water. One study concluded that tires could be responsible for as much as 28 percent of the microplastics in global oceans; another found them to be among the largest sources of such pollutants in the San Francisco Bay. Microplastics can be consumed by tiny aquatic organisms, wreaking havoc as they travel up food chains. A University of Washington study in 2020 traced a collapse in Northwestern-coho-salmon populations to 6PPD, a chemical added to tires to slow their wearing down.

The smallest tire particles, measured in mere nanometers, can enter our lungs and spread to our organs. Various tire components have been linked to chronic conditions including respiratory problems, kidney damage, neurological damage, and birth defects—a particular concern in neighborhoods adjacent to highways, whose residents skew low-income and minority. Tire particles could also affect us through our food because their chemicals can work their way into the algae and grass consumed by fish and cows. In the U.S., tire emissions aren’t regulated at all; though more stringent rules have made cars cleaner, research reported in The Guardian last year found that in newer cars, pollution from tires is much greater than tailpipe emissions.

Electrification is poised to make these problems significantly worse. EVs use “regenerative braking,” which captures energy as they slow down; all braking causes tire friction, but EVs are designed to automatically do so more often in order to gain small amounts of power. Another factor is torque, or engine power. With instant torque, EVs are able to accelerate significantly faster than gas cars. The Kia EV6 SUV, for instance, goes from zero to 60 miles per hour in 3.5 seconds, comparable to a gas-powered Aston Martin DBS 770 Ultimate. “With an average Tesla you can win a drag race with a Porsche,” Masen said. “That’s not good for the tires.”

EVs can also be very heavy, which further worsens tire wear. The addition of a massive battery can dramatically increase a car’s weight: A Ford F-150 Lightning, for instance, weighs about 35 percent more than a gas-powered F-150. The Hummer EV is even more gigantic; its battery alone weighs roughly as much as some Toyota Corolla models.

EV owners have already started noticing that their tires are wearing down quickly. A recent survey conducted by J.D. Power and Associates found that rapid treadwear is the biggest complaint that EV owners have about their tires. “They’re expecting 40,000 miles out of their tires, and they’re getting 13,000,” Ashley Edgar, J.D. Power’s senior director of automotive-supplier benchmarking and alternative mobility, told me.

With both tire-emissions analysis and EV adoption still in their infancy, it’s hard to say how much worse the pollution problems could grow. Masen hopes that the urgency of the issue will push researchers and the industry to look for potential fixes, but developing solutions will take time, and heavy, quick EVs make the problem tougher. “The tire people look at the tires, the car people look at the cars, and the road people look at the roads, but it needs to come together,” he said.

Some tire companies have launched new EV-specific products that are designed for added durability. Earlier this year, Bridgestone unveiled the Turanza EV, a new model that the company claims “is engineered to elevate your EV experience with excellent tread life.” Such specialized EV tires don’t come cheap: Bridgestone’s website lists them for $315.99 with a 50,000 mile warranty, compared with $295.99 and 80,000 miles for the non-EV version. Better tires can help, but only to an extent. The bigger issue is that many U.S. automakers have built part of their business strategy around selling hefty SUVs and trucks with juicy profit margins, and they will continue doing so. Sedans are becoming an endangered species on U.S. car lots, where about four out of five new cars are either an SUV or a truck. As EV sales have grown, the cars are only getting bigger; GM recently killed off the modest-size Chevy Bolt—its most popular electric model—and is retooling its factory to instead build electric pickup trucks.    

Carmakers could, if they chose, offer Ameicans the kinds of small EVs that are available in other countries, but no such move seems forthcoming. They could also temper their EVs’ acceleration, thereby reducing tire erosion. Instead, they are opting to sell electric SUVs that resemble race cars. Zero-to-60 speeds have been a mainstay of car marketing for decades, and the stunning pickup of EVs might, theoretically, attract new buyers. But it quickens tire erosion while serving no practical purpose. “If you can get from zero to 60 in seven seconds, you’re fine,” Jennifer Stockburger, the director of operations at the Consumer Reports auto-test center, told me. “Anything beyond that is a fun factor.”

The threat of growing tire pollution is hardly the only societal danger that the auto industry is foisting on the American public through its large and fast EVs. Tires that wear out quicker present other safety hazards: “Braking, hydroplaning, and winter traction could get worse, Stockburger said, “and then you’ve got this heavy vehicle spinning out.” Such cars could endanger pedestrians, bikers, and other drivers, deepening a roadway-safety crisis that is unique to the U.S. And the huge batteries they require consume scarce minerals that could otherwise power smaller, more efficient models.

These problems could be avoided if the federal government took a stand against unnecessary EV speed and size. National Transportation Safety Board Chair Jennifer Homendy has warned about these dangers, but Congress and the Department of Transportation have avoided the issue. The threat of worsening tire pollution is yet another danger of putting so much power over the future of our planet in the hands of car companies. Even as they reduce one kind of pollution, they might make another kind worse.