An Epidemic Supplanted by a Pandemic: Vaping-related Illness and COVID-19

Yoo Mee Shin, MD; Daniel P. Hunt, MD; Joyce Akwe, MD, MPH


South Med J. 2022;115(1):8-12. 

In This Article

How E-cigarettes Work

E-cigarettes are battery-powered devices with four components: a solution cartridge, a vaporizing chamber, a heating element, and a battery.[1] The solution cartridge contains refillable or exchangeable liquid (vape liquid or e-cigarette liquid) that usually includes nicotine, flavoring, and a delivery system (propyleneglycol or glycerin or even both). The composition of the liquid and the concentration of the substances in the liquid are variable and at times inconsistent with the label.[15]

The heating element provides heat to the liquid chamber for aerosolization of the liquid containing nicotine and other substances. Most e-cigarette models give the user the option to select the amount of aerosol produced and the nicotine concentration. The aerosol is usually held in a chamber with the heating element until use.[1]

The battery supplies power to the heating element, which aerosolizes the solution in the liquid chamber. The size and shape of the battery contributes to the size and shape of the e-cigarette.[1] The power is turned on manually or automatically. E-cigarettes with an automatic button function like regular cigarettes in that inhalation activates the device, whereas e-cigarettes with a manual battery have a button that must be pressed to activate the device to produce heat.[16] Some of the batteries can overheat and explode if inappropriately charged. Explosions also have been reported from mistaken attempts to light up these cigarettes with a flame lighter.[1] E-cigarettes have continued to evolve from first-generation devices in size, shape, and ability to customize. The second-, third-, and fourth-generation devices allow for different types of customization.

First-generation e-cigarettes look like conventional tobacco cigarettes. They are battery operated and have an atomizer and a cartridge. In the most recent first-generation e-cigarettes, the atomizer (responsible for heating up the liquid) and the cartridge have been replaced by the cartomizer, which is an atomizer and a cartridge combined. The cartomizer then connects to the battery. Some of them are one-time-use batteries, while others have a rechargeable battery. These devices are available with different flavors and nicotine concentrations.[7]

Second-generation e-cigarettes are usually larger, with higher capacity batteries and larger separate refillable cartridges or tanks. Cartridges in second-generation e-cigarettes are refillable with various types of e-cigarette or vape liquid. Some second-generation e-cigarettes have a manual switch that allows the user to regulate the frequency and length of puffs.

Third-generation e-cigarettes are similar to second-generation e-cigarettes, but they allow for more customization and are therefore also known as personalized vaporizers or aerosols.[7] They come with a large range of battery and atomizer options. Some devices allow the user to adjust the resistance of the atomizer to produce higher heating temperatures. Users also can pair different atomizers with high-capacity batteries to increase vapor production and battery life.[7]

Fourth-generation e-cigarettes are rechargeable devices with replaceable cartridges that contain nicotine and flavorings. They are also known as "pod-mod devices" and are increasingly popular among adolescents;[17] JUUL is a popular brand (it looks like a thumb drive). These devices contain nicotine in a form that is less irritating to the throat and thus tend to deliver higher concentrations of nicotine.