Background and Description of E-Cigarette Products and Solutions

Electronic cigarettes (e-cigarettes) are the most popular tobacco product among youth in the United States. The function of all e-cigarettes and other vaping products is similar: to heat a liquid to produce an aerosol for inhalation. The act of inhaling aerosols generated from e-cigarettes is commonly referred to as vaping. The overall structure of e-cigarettes, common to all generations of the product, includes a battery, atomizer, and a reservoir containing liquid. However, there is significant variability in product design and customizability. Liquids used in e-cigarettes are usually (but not always) composed of nicotine, as well as at least one solvent, usually propylene glycol (PG) and/or vegetable glycerin (VG), flavorings (tobacco, menthol, candy or beverage themed, and more), and additives (e.g., sweeteners). While e-cigarettes have become highly effective in delivering nicotine, these products have also been used to vaporize other psychoactive substances, including cannabis products containing tetrahydrocannabinol (THC) and cannabidiol (CBD). In this chapter, we describe the basic structure of e-cigarettes and the significant differences among the different generations of products. We highlight what is known about the liquids and substances used in these devices, including nicotine, cannabinoids, flavorings, and potentially toxic chemicals.