Tire pollution consists of a toxic mix of microplastics and heavy metals that are shed into the air, soil, and water as tires wear down as they travel on roads. Over six million tons of rubber and particles are shed from tires globally every year.
Tires are a major source of pollution. Between 3% and 7% of fine particulate matter (PM2.5) in roadside air comes from tire wear. As much as 45% of microplastics in the oceans come from tires.
A significant pollutant is the chemical 6PPD, which is added to tires. The substance is crucial for tire safety, preventing structural failure by keeping tire rubber flexible.
6PPD on roads from tire wear reacts with ozone and creates a chemical byproduct called 6PPD-Q. When it rains, stormwater washes 6PPD-Q into rivers and streams, where it is extremely lethal to many fish species including coho salmon.
A new study has found that many of the chemicals derived from tire wear may pose a threat to humans when inhaled. The researchers exposed human immune cells to a mixture of tire-derived pollutants as well as to 6PPD-Q on its own. The mixture caused rapid cell death as well as lesser ill effects according to the research.
6PPD-Q itself was not particularly harmful to human cells, but the results suggest that focusing on one specific compound in tire pollution may underestimate the overall potential dangers. The findings are not conclusive, but they do indicate that the risks from airborne tire pollution may be greater than previously thought.
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References:
Tire Pollution May Threaten Human Health, Study Finds
