Your Car's Biggest Source of Pollution Isn't the Tailpipe

Studies point to tires and brakes as the bigger culprits
By Steve Huff,  Newser Staff
Posted Jul 16, 2023 5:15 PM CDT
Updated Jul 16, 2023 9:03 PM CDT
Your Car's Biggest Source of Pollution Isn't the Tailpipe
   (Getty Images / mmz)

Scientists researching the way vehicles spew potentially dangerous pollutants into the environment have reached some surprising conclusions about the culprits. The Washington Post reports your car's exhaust pipe isn't the only source of harmful particulates; brake and tire emissions are a problem too, and a growing one. Federal and state regulations have led to marked improvements in emissions systems, but no such regulations exist for brakes and tires. Researchers found degrading tires and brake pads release particulate matter that ranges from the microscopic to the visible—and ingestible, with the Post noting the particles "can enter through our bloodstream and harm our organs."

Not surprisingly, the problem isn't confined to the US. The Guardian reports that England's chief medical officer explained the situation this month to parliament thusly: "I don't think we have really thought about how to reduce air pollution from [tires] previously because it's been such a small proportion." That proportion is growing "now that we're getting rid of many or all of the tailpipe emissions." And electric vehicles aren't our ticket out. On the contrary, they could cause these emissions to grow because they're heavier, which increases the wear on tires. University of California Riverside professor Heejung Jung raises another issue for the Post. The chemical composition of non-tailpipe emissions "can be potentially more toxic, especially for brakes' [particulate matter] … they're all metallic."

Green Car Congress pointed to a paper from the Imperial College of London, which estimated in 2021 that "52% of all small particle pollution from road transport came from tires and brakes." Additionally, a total of 6 million tons of TWP, or tire wear particles, enter the air every year. Inhaling them isn't the only problem. Particles shed by worn tires can make it into waterways via runoff from rainfall and eventually into our bloodstreams, leaching substances like zinc or lead—toxic heavy metals. Additionally, tire particulates could make microplastic pollution even worse. Lead study author Dr. Zhengchu Tan urged "policymakers and scientists to embark on ambitious research into tire wear pollution to fully understand and reduce their impacts on biodiversity and health, as well as research to reduce the generation of these particles." (More vehicle emissions stories.)

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