Spatiotemporal dynamics of tire wear particles reveal escalating emission inequalities across China’s road network

Summary

Non-exhaust emissions are rapidly emerging as a major contributor to traffic related particulate pollution, yet their emission patterns and impacts remain poorly constrained at large spatial scales. Here we present a nationwide, road network-resolved assessment of tire and road wear particles (TRWP), inte grating harmonized field measurements, machine-learning models, traffic activity data, and epidemiological models. China’s road network emitted 425kt of TRWP-derived fine particulate matter (PM2.5)in2023,nearly80% originating from modeled vehicle-induced resuspension. These emissions and exposures exhibit spatial inequalities, concentrating health risks in densely populated economic corridors and megacities. The contribution of TRWP to PM2.5 is projected to increase 34-fold from 2011 to 2050, with tire-derived particles accounting for 67% of traffic-related PM2.5 emissions by 2050. Implementing synergistic mitigation strategies could reduce these annual emissions by 41%. Our findings highlight an urgent need to expand transport and public health strategies beyond exhaust control to include non-exhaust particle mitigation.