Tire emissions during the use phase of tires – current and future trends

Abstract

The ongoing energy transition, marked by notable advancements in electric vehicles, presents new challenges related to tire emissions. In addition, these emissions and their distribution may be affected by other future trends like prolonged heat periods and an increase in stormwater events, which are both related to the ongoing climate change. An understanding of future trends and robust data on tire emissions during the use phase that inform these trends is essential for evaluating the potential environmental impact and implementing effective mitigation strategies even today. In this structured literature review current and future environmental exposure pathways of tire emissions during vehicle use including particulate tire wear, leachables and volatiles are discussed. A total of 502 publications between 1985 and 2024 were reviewed, resulting in a conceptual exposure model (CEM) for tire emissions during the use phase. Analytical tools are discussed and a proposal for a fit-for-purpose analytical methodology is adapted from microplastic research to inform the CEM of tire emissions. This concept follows a tiered approach covering exploratory, screening, mass, single particle, and chemical analysis of environmental samples with dedicated analytical methods and quality assessment criteria for each tier. Further, the current state of knowledge on factors controlling tire emissions is assessed to determine whether sufficient information is currently available to predict future emissions from tires during use. In conclusion, knowledge needs that need to be solved for a predictive environmental assessment of tire emissions during the use phase are identified.