Unveiling Chlorinated Paraffin Emissions via Tire\nWear and Airborne Release from Various Types of Tires

Ubiquitous\nvehicle operation leads to the continuous emission of\ntire additives into the environment via tire wear particles (TWPs)\nand air emission. Significant knowledge gaps remain regarding the\nabundant additive chlorinated paraffins (CPs) in tires. This work\ninvestigates short-, median-, and long-chain CPs (SCCPs, MCCPs, and\nLCCPs) in end-of-life and new tires of the same models for sedans,\nSUVs, trucks, and vans in China. CP levels ranged from 81–245\nμg/g (mean 137 μg/g) in 2018 end-of-life tires and 6–183\nμg/g (mean 71 μg/g) in 2023 new tires, dominated by SCCPs\nand MCCPs (mainly C<sub>13–14</sub>). A decreasing trend of\nCPs (2018–2023) was observed in SUV, truck, and van tires.\nTire mass evaluation and a simulated air emission experiment indicated\nthat TWP emission and air emission contributed approximately 20% and\n6%, respectively, to the total CP loads of tires over their lifespan.\nTWP emissions made tires significantly more efficient in spreading\nCPs compared with other CP-containing products. The discharge of CPs\nfrom TWPs was estimated at 160 tons per year in China, with a dominant\ncontribution from sedans and heavy trucks. This study enhances understanding\nof CPs’ presence and environmental emissions in tires and underscores\nthe significant impact of tire-derived CPs.