The environmental fate of tire and road wear particles (TRWPs) receives increasing attention due to the per capita emission volumes of 0.2–5.5 kg/(cap year) and recent reports on the environmental hazard of TRWP constituents.
It is expected that aging impacts the fate of TRWP in the environment but detailed knowledge is to-date quite limited. Making use of available information on tire aging, knowledge on environmental aging processes such as thermooxidation, photooxidation, ozonolysis, shear stress, biodegradation and leaching was reviewed in this study.
The study concludes that the findings and methods from tire aging can be partially applied to study aging of TRWPs in the environment. There is a complex interplay between aging processes in the environment that needs to be considered in future aging studies. In addition to existing basic qualitative understanding of the aging processes, quantitative understanding of TRWP aging is largely lacking. Aging in the environment needs to consider the TRWPs as well as chemicals released.
The study also elaborates on next-steps for filling knowledge gaps on the aging of TRWPs in the environment.