The environmental and health impacts of tyre wear particles

29 Apr 2024

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Six million tonnes of tyre wear particles are estimated to be released to the environment globally each year. Tyre wear particles and their chemical additives are an environmental concern due to their potential impacts on ecosystems and wildlife, as tyre wear particles are generated through normal use of road vehicles, though higher emissions are present where heavy braking occurs.

The particles accumulate on the road surface and can be washed into waterways and surrounding land during heavy rain and storm events. Recent work has linked the presence of 6PPD-quinone in water to salmon deaths in the Northwest of the USA. 6PPD is a tyre additive used to prevent tyres from breaking down due to reactions with ozone and other reactive oxygen species in the air, where it forms 6PPD-quinone. 6PPD is just one of many 100s of additives in tyres and limited information is available regarding the emissions, environmental fate, and effects of many of these additives.

Research on the environmental and health impacts of tyre wear particles is a growing area and the potential risks are receiving the attention of environmental regulators in Europe and North America. The European Chemicals Agency has published an Assessment of Regulatory Needs on 6PPD and related additives in tyres where they are considering possible regulatory actions for the group of substances. The United States Environment Protection Agency has begun the process of considering the regulation of 6PPD with a potential intervention likely to be put in place that requires further information on the chemical safety of 6PPD.

The situation is complex considering the important technical use of chemical additives in tyres for performance and safety, in balance with the need to consider potential risks to wildlife and human health that may require regulatory intervention. There is an urgent need for a review of the chemical additives commonly used in tyres which should also extend to the evaluation of hazard, exposure and risks from alternatives to these additives. Considering potential risk management action would provide a useful resource for all stakeholders in this space.

Ricardo’s Environmental Chemistry and Toxicology team have extensive experience of evaluating the hazard, exposure and risk from chemicals in the environment with particular emphasis on environmental persistence assessment and ecotoxicology under the REACH and CLP Regulations. Our experience and expertise means we are well placed to develop solutions to address this complex issue.