Behind the Paper

Secondhand exposure to e-cigarette aerosol and lung health

E-cigarettes are often framed as a personal choice. You use them, you take the risk. That breaks down when others share the same air. We know much about active use, far less about bystanders. So the question is simple: is secondhand e-cigarette aerosol harmless, or does it affect the lungs?
Ardie Barry Sailis Apr 03, 2026

Review Article

Effects of secondhand exposure to e-cigarette aerosol on lung health: a systematic review

         

What we found

Even with only a handful of studies, the pattern is clear.

In adolescents and young adults:
Living with someone who use e-cigarette is linked to more cough, shortness of breath, and asthma-related symptoms. The more frequent the exposure, the higher the risk.

In healthy adults (short-term exposure):
Just 30 minutes in an e-cigarette aerosol environment can cause:

  • Throat and airway irritation
  • Cough and discomfort
  • Measurable changes in airway function

Some effects don’t disappear immediately after exposure ends.

In people with lung disease (COPD):
A few hours of exposure can:

  • Increase inflammatory markers
  • Affect lung-related proteins
  • Slightly worsen lung function

These are not just mild annoyances. They interact with existing disease.

What’s actually in the air

E-cigarette aerosol isn’t smoke, but it’s not clean air either.

It contains:

  • Ultrafine particles that reach deep into the lungs
  • Volatile chemicals
  • Reactive compounds like aldehydes
  • Nicotine

And importantly, these don’t stay with the user. They spread into the surrounding air.

The key point

Across all studies, the same thing shows up:

  • People report symptoms
  • Lung function changes are detectable
  • Inflammatory signals shift
  • Air quality measurements confirm exposure

Different angles, same conclusion.
Secondhand exposure is real, and it has biological effects.

Putting it in context

Yes, the effects are generally smaller than cigarette smoke. But “smaller” is not the same as “safe.” And unlike active use, this exposure is involuntary. That matters.

What we still don’t know

Most studies are short-term or observational. So there are open questions:

  • Do repeated exposures add up over time?
  • Does the body adapt, or does damage accumulate?

Right now, both are possible.

Why this matters

This shifts the conversation.

It is no longer only about whether e-cigarette use is safer for the user. It is about what non-users inhale, often without choice. The evidence points to a clear conclusion: secondhand e-cigarette exposure is not harmless.

Risk may be lower than smoking, but lung effects are still detectable. That is sufficient to warrant caution, particularly for children and those with respiratory disease.

Reference

Sailis AB, Noh MABM, Leo BF, Faruqu FN, Yee A, Sim MS. Effects of secondhand exposure to e-cigarette aerosol on lung health: a systematic review. Journal of Public Health. 2026. https://doi.org/10.1007/s10389-026-02740-0

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