Vaping is popular with teens. In 2022, an estimated 14% of US high school students—around 2.14 million—and more than 3% of middle school students—around 380,000—reported vaping in the preceding month, note the researchers. Certain metals have been identified in e-cigarette aerosols and liquids. Their absorption is especially harmful during periods of development, say the researchers, citing research showing that increased levels of exposure are linked to cognitive impairment, behavioral disturbances, respiratory complications, cancer, and cardiovascular disease in children.