Vaping continues to rise in popularity, with one 10-year population-based study published in 2024 finding the numbers of young people, former smokers, and never-smokers who vape had all increased.

While many people see vaping as a healthy alternative to traditional cigarettes, there are health concerns surrounding vaping. One of the most prominent concerns for people, especially with families, is secondhand vape exposure.

Here, we look at the risks surrounding secondhand vape exposure and compare it to secondhand smoke. 

Understanding Secondhand Smoke vs. Secondhand Vapor

Secondhand smoke is the inhalation of smoke from cigarettes and exhaled cigarette smoke containing toxic chemicals.

Secondhand smoke (SHS) is a significant health concern, exposing nonsmokers to an increased risk of heart disease, lung cancer, and a range of respiratory illnesses.

 According to a2023 study, “SHS exposure is associated with the risk of COPD, especially for individuals with a long time exposed,” while a2024 study found “exposure to SHS increases by more than 20% the risk of lung cancer among never-smokers, providing definitive evidence of the association between SHS exposure and lung cancer risk.”

There is less known about secondhand vapor, also known as secondhand aerosol, than secondhand smoke, but mounting evidence suggests breathing in vapor may also pose health risks.

A2024 study compared nicotine absorption in U.S. children between secondhand smoke and secondhand vapor and found “nicotine absorption was much lower in children who were exposed to secondhand vapor vs secondhand smoke, but higher than in those exposed to neither.”

While it may not be as bad as secondhand smoke, this study suggests it should be avoided, especially around children. 

You can tell the difference between secondhand smoke and vapor because smoke from a combustible cigarette is usually thicker and gray. In contrast, vapor is white or clear and diffuses more quickly. 

What’s in Vape Aerosol?

Secondhand vapor or vape aerosol contains the same things in vape juice: nicotine, propylene glycol (PG) and/or vegetable glycerin (VG), flavorings, and sometimes other chemical fillers.

While there are fewer toxins and carcinogens in vape aerosol than secondhand smoke from a combustible cigarette, it may still contain harmful chemicals like formaldehyde, acetaldehyde, acrolein, benzene, and even heavy metals from burning coils. 

Is Secondhand Vape Exposure Harmful?

While there is a long way to go until we know the long-term damage that secondhand vapor can cause, studies suggest that breathing in somebody else’s vape plume can be harmful, especially in children and adults who regularly breathe secondhand vapor and people with preexisting health conditions like asthma.

The health concerns for bystanders include respiratory irritation and nicotine exposure. According to a2022 study into secondhand nicotine vaping at home, “exposure was associated with increased risk of bronchitic symptoms and shortness of breath among young adults.” 

According toWHO data on secondhand smoke and aerosol, “in some countries of the WHO European Region, up to 60% of children are exposed to SHS at home, making it a significant public health concern.” 

The WHO suggests that “only a home that is 100% smoke-free effectively protects the health of all household members.

Making a home smoke-free offers numerous benefits, including improved health for all individuals, especially children and pregnant women, reduced fire risks associated with smoking, encouragement for smokers to quit or smoke less, and support for recent quitters to avoid lapsing.” 

Public Perception and Policy

When vapes came on the scene, they were hailed by everybody from average Joes to healthcare professionals as being a healthy alternative to cigarette smoking.

While there are many reasons why choosing to vape is a healthier option than smoking a regular cigarette, there are still health risks associated with vaping. However, public perception does not always match the reality of the harm caused by vaping.

One of the findings in a2023 survey focusing on misconceptions about vaping among young people was: "When asked whether vaping had negative health impacts, only 238 (24%) participants strongly agreed with this statement, while a majority (64%) neither agreed nor disagreed or only somewhat agreed." 

Indoor vaping and vaping in public spaces are less common than they were a few years ago. Most U.S. hotels, airports, schools, workplaces, and other indoor public spaces like malls now require people who vape to do so in designated smoking areas.

Expert Opinions and Ongoing Research

The American Heart Association asked Dr. Talat Islam, an assistant professor of research population and public health sciences at the University of Southern California in Los Angeles, for his thoughts on secondhand aerosols: "Aerosols from vaping contain heavy metals and ultrafine particles," Islam said.

"If somebody else is vaping in the same area, you're breathing it – those particles are entering your lungs, where they can do damage."

The American Nonsmokers' Rights Association asked Dr. Stanton Glantz, Director of the Center for Tobacco Control Research and Education at the University of California, San Francisco, for his thoughts:  "If you are around somebody who is using e-cigarettes, you are breathing an aerosol of exhaled nicotine, ultra-fine particles, volatile organic compounds, and other toxins."

Studies like thiscross-sectional study of 1777 US children aged 3 to 11found nicotine absorption lower in secondhand vapor than secondhand smoke: "nicotine absorption was 83.6% lower in those exposed to secondhand vapor only and 96.7% lower in those exposed to neither."

However, further long-term data is necessary to truly understand the damage that exposure to secondhand aerosols can do. 

Conclusion

Secondhand vapor, or secondhand aerosol, contains fewer carcinogens and toxins than secondhand smoke from combustible cigarettes. However, secondhand vapor still poses a health risk due to harmful chemicals like formaldehyde, acetaldehyde, acrolein, benzene, and even heavy metals from burning coils.

People exposed to it regularly, pregnant women, children, and people with preexisting health conditions like asthma are especially vulnerable. Vape emissions should be treated the same as secondhand smoke until further research is known.