https://www.nationalgeographic.com/environment/article/tires-unseen-plastic-polluter https://www.nationalgeographic.com/environment/article/tires... Several st

https://www.nationalgeographic.com/environment/article/tires-unseen-plastic-polluter https://www.nationalgeographic.com/environment/article/tires... Several studies apparently. 10-30 percent depending on the study.