Chris Witty MP: Tyres will soon pose a greater threat than exhausts

England’s Chief Medical Officer, Sir Chris Whitty, has recently drawn attention to a subtle yet critical source of pollution: car tyres. In his address to the Environmental Audit Committee in early July, Whitty emphasized the urgency of addressing tyre pollution, which, he argues, could potentially worsen in a future dominated by electric vehicles. 

Despite being cleaner in terms of emissions, the shift towards electric vehicles does not completely alleviate pollution-related problems. This paradigm shift promises a marked reduction in pollutants such as nitrogen oxides from exhausts, however, it simultaneously highlights an often-overlooked source of environmental pollution: particulates from tyre and brake wear. According to a report by Imperial College London, toxic chemicals are released from tyre wear particles. This includes harmful substances like polyaromatic hydrocarbons, benzothiazoles, zinc, and lead, which either hang in the air or seep into nearby soil and bodies of water. Whitty warns that the heavier weights of electric vehicles might slightly increase tyre-related particle emissions, a concern that requires immediate attention.  

There is a growing body of research suggesting that tiny particles produced by tyre wear, together with those from road surfaces and markings, pose a significant health risk, now surpassing the hazards of exhaust emissions. These particulates can be deeply inhaled into the lungs and even infiltrate the food chain. According to Jonathan Grigg, a professor of paediatric respiratory and environmental medicine at Queen Mary University of London, further research is needed to understand the health effects of these non-combustion particles. Moreover, particles from tyre and brake wear, road abrasions, and their paint markings contributed to about 76% of all small particle pollution from road transport in 2021, as per a UK government data. This figure is remarkably higher than the mere 15% from car exhausts, underscoring the urgency of the tyre pollution issue. Experts and policymakers are calling for further research on tyre wear and new solutions to this pressing problem. 

This issue has taken on renewed importance in the light of recent tests showing that modern cars generate nearly 2000 times more particle pollution from tyre wear than exhaust emissions. Nick Molden from Emissions Analytics warns that tyre pollution could swiftly become a major regulatory issue, given that tyre particles contain a wide range of toxic organic compounds, including carcinogens. The tests revealed that, with each kilometre driven, tyres produce more than a trillion ultrafine particles. These particles, which measure less than 23 nanometres, pose a unique health risk due to their ability to infiltrate organs through the bloodstream. 

Meanwhile, efforts to reduce tyre emissions are gaining traction. Experimental trials of new tyre designs sponsored by Transport for London found them to emit 35% fewer pollutants. Similarly, the EU is working on legislation to regulate tyre emissions, with new standards expected to be in place by 2025. Regulatory tools and surveillance measures for tyre wear and chemical content are currently lacking. Given the substantial variation in wear rate and toxic chemical content among different tyre brands, Molden suggests that even low-cost changes could significantly reduce their environmental impact. 

The call for urgent action on tyre pollution is echoed by others in the field. The Department of Environment, Food and Rural Affairs stated that they are "conducting research and supporting the development of international legislation to better understand the scale and impacts of non-exhaust emissions, including automobile tyre and brake wear."