- Youth exposed to secondhand vape aerosol have six to seven times lower nicotine levels than those exposed to cigarette smoke.
- Carcinogen exposure is over four times lower in teens exposed only to vape aerosol versus cigarette smoke.
- Only 1.5 per cent of U.S. adolescents reported secondhand vape exposure, compared with 18.3 per cent exposed to cigarette smoke – showing vaping’s much smaller footprint.
- Study confirms: secondhand vaping poses far lower health risks to youth than secondhand smoking.
Secondhand vape aerosol exposes bystanders – especially youth – to dramatically lower levels of harmful chemicals compared to cigarette smoke, a new peer-reviewed study has found.
The study, published in the journal Addictive Behaviours, analysed biomarker data from almost 2,400 American adolescents (aged 12 to 17) who were non-users of tobacco or nicotine products.
By focusing solely on secondhand exposure, the researchers were able to directly compare the impact of secondhand smoke from cigarettes and secondhand aerosol from vapes.
Vaping leaves far less toxic residue behind
They conclusively found that vaping leaves far less toxic residue behind – and exposes those nearby to significantly fewer harmful substances – than combustible cigarettes.
The study, using data from the Population Assessment of Tobacco and Health (PATH) Study, found that adolescents exposed only to secondhand vaping aerosol had mean cotinine levels – a marker of nicotine exposure – of just 0.5 ng/mg creatinine (a compound used to normalise urine measurements).
In comparison, those exposed to secondhand smoke from cigarettes had cotinine levels six to seven times higher (3.0 ng/mg creatinine).
Lower carcinogen exposure
Exposure to the carcinogen NNAL was also dramatically different: just 0.9 pg/mg for vape aerosol-exposed youth, compared to 4.1 pg/mg for secondhand smoke-exposed youth – more than four times higher.
The authors concluded: “Secondhand vaping aerosol poses a lower exposure risk to youth non-tobacco users than combustible cigarette smoke.”
Their findings underline the fundamental difference between burning tobacco – which releases thousands of harmful and cancer-causing chemicals – and using vapes, which heat e-liquids without combustion.
For years, vaping advocates have emphasised that vapes represent a harm reduction breakthrough, not just for adult smokers looking to quit but also for public spaces.
Unlike traditional cigarettes, vapes do not emit sidestream smoke (smoke released into the air) between puffs, and their aerosol contains a far less toxic chemical profile.
A fraction of harmful chemicals
The new study shows that even when youth are exposed secondhand, the level of harmful chemicals they encounter from vaping is a fraction of what they would inhale around cigarette smoke.
The researchers emphasised that exposure patterns should inform smart, evidence-based public policy.
“The distinct exposure patterns emphasise the importance of implementing tobacco-free policies to reduce youth exposure to environments where combustible tobacco or e-cigarette use occurs,” they said.
They note that over 19,000 Americans die each year from diseases caused by secondhand cigarette smoke, highlighting the tremendous public health gains to be made from reducing smoking.
Findings back up previous studies
A separate study published in JAMA Network Open in July, found children exposed to vaping indoors absorb less than one seventh the amount of nicotine as children who are exposed to indoor smoking.
The research by University College London (UCL) looked at blood tests and survey data for 1,777 children aged three to 11 in the U.S.
Lead author Dr. Harry Tattan-Birch, of the UCL Institute of Epidemiology & Health Care, said: “Our study shows, using data from the real world rather than an artificial lab setting, that nicotine absorption is much lower from second-hand vapor than from second-hand smoking.
“Nicotine itself is of limited risk, but it shows what the highest possible exposure might be from second-hand vaping.”
He added that exposure to harmful non-nicotine substances in vapes would likely be much lower still, as they deliver similar levels of nicotine to tobacco but contain only a fraction of the toxicants and carcinogens.
The researchers looked at nicotine absorption in children, but said the findings were likely to be similar for adults.
