The unexpected way cars contribute to pollution

It may be time to reinvent the wheel

Tires stacked in braided pattern
"We all know that tires wear down, but no one ever really thinks about where that material goes."
(Image credit: Jack Adams / Getty Images)

Cars and other vehicles are a great source of pollution, not just due to their exhaust fumes. Your car's tires and brakes contribute substantially to particulates in the air. In turn, these parts, even in electric vehicles, contribute to health problems and climate change.

How do tires and brakes create pollution?

The pollution comes from the wear and tear of these parts over time. The dust from tires and brakes can make up particulate matter in the air, both visible and invisible to the eye, that we then inhale. "These nontailpipe emissions are becoming an issue for two reasons," said Heejung Jung, a professor at the University of California, Riverside, to The Washington Post. "One, it hasn't been regulated. Second, its chemical composition can be potentially more toxic, especially for brakes' [particulate matter] … they're all metallic."

Tire dust is one of the most prevalent microplastics with over 6 million metric tons of it ending up in the air and waterways annually, according to CNN. "We all know that tires wear down, but no one ever really thinks about where that material goes, and it's going into our air and water," remarked Siobhan Anderson, the chief scientific officer and co-founder of the startup The Tyre Collective to CNN. In some ways, tire dust is more potent than tailpipe emission. In 2020, a study found that tire chemicals may have contributed to several salmon deaths in the U.S. Pacific Northwest.

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The previous assumption held that "big chunks of rubber breaking off tires" were caught in drains and that it wasn't all that large of a concern, explained Nick Molden, the founder and CEO of Emissions Analytics to the Post. "What we've shown from our testing is that it's a mixture of bigger particles but also ultrafine particles." He added, "Water is likely to be the single biggest destination of these particles." The smallest particles are PM 2.5 pollution, which is small enough to be inhaled and cause respiratory problems.

What's being done about it?

Since cars aren't going anywhere anytime soon, the better solution is to alter the materials used to make tires and brakes. Currently, the parts are usually made of synthetic rubber from crude oil, which contains several chemicals including some known to be carcinogenic.

One of the ideas is to make tires from a newer, natural rubber derived from dandelions. There's a collaborative initiative between tire and rubber company Goodyear, the Department of Defense, the Air Force Research Lab, BioMADE and Farmed Materials to do just that. "Global demand for natural rubber continues to grow, and it remains a key raw material for the tire industry," said Chris Helsel, the senior vice president of Global Operations and chief technology officer for Goodyear, in a press release. "This is a critical time to develop a domestic source of natural rubber, which may help mitigate future supply chain challenges."

The Tyre Collective is creating a "wheel-mounted device that collects the tiny particles on electrostatically charged copper plates" that then "will be emptied monthly by technicians at garages," according to CNN. The particles could even be upcycled into other objects going forward.

The toxic chemicals in tires are "negatively impacting wildlife, the environment and human health," Lisa Erdle, the director of research and innovation for The 5 Gyres Institute, told CNN. She added, "If this issue goes unchecked, we'll see an accumulation of tire dust in the environment."

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Devika Rao

Devika Rao is a staff writer for The Week. She graduated from Cornell University with a degree in Environment and Sustainability and a minor in Climate Change. Previously, she worked as a Policy and Advocacy associate in the nonprofit space advocating for environmental action from the business perspective. She is passionate about the environment, books, and music.