Many people assume vaping is harmless to bystanders, but secondhand aerosol can contain ultrafine particles and chemical residues. Researchers are examining how exposure may affect airways and overall health, especially for children What Does Vaping Do to Your Lungs? Johns Hopkins Medicine About E Cigarettes (Vapes) Smoking and Tobacco Use CDC Delaware law restricting vaping takes hold WHYY Vape e cigarette in extreme closeup macro with trails of vapor smoke Stock Photo Alamy