Dai H, et al. - Researchers sought to investigate the trends in self-reported secondhand aerosol (SHA) exposure among US adolescents and analyzed the relationships between SHA, susceptibility to tobacco use, and exposure to e-cigarette marketing among never tobacco users. In US high school students, the prevalence of current electronic cigarette use increased dramatically from 11.7% in 2017 to 20.8% in 2018. It was noted that exposure to SHA from e-cigarettes is not harmless, as e-cigarette aerosol contains nicotine and potentially harmful substances, including carbonyl compounds, tobacco-specific nitrosamines, heavy metals, and glycols. In recent years, the utilization of E-cigarette may serve as a gateway to cigarette initiation, and e-cigarette makers have significantly increased their advertising expenditures. The data demonstrated that exposure to secondhand aerosol may improve the curiosity about e-cigarettes and perceived pervasiveness of e-cigarette marketing and additional raise the susceptibility of tobacco use among never tobacco users.