Bio: Yun Wang is an associate professor on the Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, China. Her current research mainly focused on the adverse effect of occupational and environmental factors. The majority of the work is devoted to identifying the health impact of nanoparticles and involving nanotoxicology and occupational ergonomics.

Abstract: Third-hand smoke (THS), the residual tobacco contamination lingering on surfaces and in dust, poses a significant yet understudied health risk, particularly for children. This study aimed to quantitatively assess THS exposure among children in Beijing and evaluate its potential health hazards. In 2023, a stratified cluster sampling method was used to survey 1,825 children, with 262 selected for detailed analysis. Environmental samples (surface wipes, textile adsorption) and internal exposure samples (urine) were collected, and tobacco-specific biomarkers (nicotine, cotinine, trans-3’-hydroxycotinine, and tobacco-specific nitrosamines) were quantified using liquid chromatography-mass spectroscopy. Results revealed that 47.45% of children were exposed to THS, with significantly higher biomarker levels in exposed children compared to controls (P<0.05). A strong positive correlation was observed between environmental and internal exposure levels (P<0.05). These findings highlight the widespread THS exposure among children in Beijing and its potential health risks, underscoring the urgent need for targeted public health interventions to mitigate this threat.