Nature Communications, Published online: 07 September 2026; doi:10.1038/s41467-026-77475-3 As vehicle exhaust emissions fall, tire and road wear particles (TRWP) are becoming a major PM2.5 source. In China, road traffic emitted 425 kt of TRWP PM2.5 in 2023, concentrating risks in cities. Without action, TRWP will grow by 2050, but targeted measures could cut emissions by 41%.