Spotlight on science and technology: electronic cigarettes


Why it matters

With millions of teens and young adults using e-cigarettes, a new generation could become addicted to nicotine and face other health risks. For some adult smokers, electronic cigarettes may be a less harmful substitute for traditional cigarettes. However, the long-term effects on users, secondary exposure and environmental effects are not yet fully understood.


What is that? Electronic cigarettes – or e-cigarettes – are battery-powered devices that convert a liquid, usually containing nicotine, into an inhalable aerosol. They are designed as an alternative to traditional cigarettes. First introduced in the United States about 15 years ago, electronic cigarettes have evolved from single-use disposables to more sophisticated devices that can be filled and personalized (Fig. 1).

Figure 1. Electronic cigarettes can vary widely in terms of design and appearance.

Electronic cigarettes are popular among teens and young adults, according to the Centers for Disease Control and Prevention (CDC). In 2019, nearly 28% of high school students and 11% of middle school students reported using e-cigarettes. About 8% of young adults aged 18 to 24 reported using e-cigarettes in 2018.

How it works? Although the design and appearance of electronic cigarettes vary, they generally work the same. An e-cigarette has four components: a battery, a cartridge or reservoir containing liquid, a heating element or atomizer, and a mouthpiece. Studies have identified a wide variety of chemicals in cartridges, liquids, and aerosols, including between 60 and 113 ingredients in different brands of liquids. According to the CDC, the aerosol of the liquid generally contains fewer harmful chemicals than the smoke from traditional cigarettes. However, the risks of injury and death from electronic cigarettes are becoming increasingly apparent, and the toxicity of some ingredients in inhaled form is largely unknown.

The liquid usually contains water and other solvents, nicotine, flavors and other substances. The liquid may also contain tetrahydrocannabinol (THC), the main psychoactive chemical in marijuana. The aerosol may contain metals, volatile organic compounds and formaldehyde, which is a known carcinogen.

The device heats the liquid, creating an aerosol. Inhalation, commonly known as vaping, deposits particles in the user’s lungs (Fig. 2). The substances in the particles, including nicotine, pass into the blood. Nicotine circulates rapidly in the brain, causing the release of dopamine, which is associated with pleasure and appetite suppression. Nicotine can be addictive. Electronic cigarettes mimic the sensory experiences of smoking a traditional cigarette, such as inhaling, exhaling, and moving from hand to mouth. These have been shown to contribute to addiction by creating additional pleasurable sensations through taste, sight and smell.

Figure 2. Substances from inhaled aerosol particles reaching the lungs, blood and brain of the e-cigarette user.

Exposure to nicotine during adolescence can affect learning, memory and attention. It can also increase the risk of future addiction to nicotine and other drugs. However, many young users report that they started using e-cigarettes because of the flavors and, according to the CDC, don’t realize they are inhaling nicotine.

How mature is he? Electronic cigarettes are relatively new. Therefore, the direct and indirect health effects are not yet fully understood, including long-term effects on users (e.g. lack of recycling and waste streams for used devices).

In addition to the risk of nicotine addiction, the use of electronic cigarettes is associated with serious lung damage. As of February 2020, lung damage from electronic cigarettes had resulted in more than 2,700 hospitalizations, mostly in young adults, and 68 deaths in the United States. Public health agencies have found that these cases are strongly linked to vitamin E acetate, an additive in some electronic cigarettes containing THC, but have not ruled out the possible contribution of other chemicals.

The Food and Drug Administration (FDA) extended its regulatory authority over tobacco products to include electronic cigarettes in May 2016. In December 2019, Congress raised the minimum age for purchasing tobacco products, including cigarettes. electronic devices, from 18 to 21 years old. The popularity of certain flavored electronic cigarette products among children, the FDA said in January 2020 that it would prioritize enforcement action against the manufacture and sale of most flavors in cartridge electronic cigarettes. In April 2020, the FDA extended the deadline for manufacturers to apply for pre-market authorization from May to September 2020, a process that includes scientific assessment of the risks and benefits of e-cigarettes to the U.S. population.


  • Possible reduction in smoking. The use of electronic cigarettes may offer opportunities to reduce the known long-term health effects of traditional smoking, such as cancer and heart disease. According to the CDC, e-cigarettes can benefit adult smokers who are not pregnant if used as a substitute, not a supplement, to traditional cigarettes. However, their long-term health effects and their effectiveness as smoking cessation devices are not yet clear, and the FDA has not approved e-cigarettes for smoking cessation.


  • Increased addiction to nicotine. For young users, e-cigarettes can lead to smoking, according to a 2018 study from the National Academies of Sciences, Engineering and Medicine. This finding could erase decades of progress in reducing smoking, the leading cause of preventable death in the United States and around the world
  • Toxicity of inhaled chemicals. The toxicity of some inhaled additives is unknown because they were not previously used for inhalation. This includes additives considered safe for ingestion in food or drink. For example, a buttery-tasting additive (diacetyl) used in electronic cigarettes is known to cause severe lung damage and death when inhaled by workers in a popcorn factory.
  • Variable risks due to lack of standardization. Differences in design and engineering influence the concentrations of chemicals in the liquid and aerosol. This likely has implications for the impact of electronic cigarettes on the health of users exposed to inhaled aerosols and non-users exposed to expired aerosols or liquid.
  • Effect on indoor and outdoor environments. Electronic cigarettes increase the concentrations of nicotine, particles and other potentially toxic substances in indoor environments. Lithium-ion batteries in devices and traces of hazardous chemicals make disposal and recycling difficult.
  • Possible impact on COVID-19 patients. Some public health officials have warned that since the virus that causes COVID-19 affects the respiratory tract, e-cigarette users and smokers may be at a higher risk of complications from COVID-19. It’s a new area of ​​research

Political background and issues

  • What are the health and environmental effects of electronic cigarettes?
  • What information and data could help policymakers better understand the potential risks and benefits of e-cigarettes compared to traditional cigarettes?
  • What additional approaches might help discourage young people from using e-cigarettes? For example, how might federal and state taxes affect usage?
  • How to make electronic cigarettes safer to reduce secondary exposure?

For more information, contact Karen Howard at (202) 512-6888 or [email protected]

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