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expert reaction to study looking at presence of third hand smoke indoors

New research, published in Science Advances, suggests that thirdhand smoke persists and spreads indoors with help from aerosol particles.


Prof Neil Thomas, Professor of Epidemiology and Research Methods, University of Birmingham, said:

“There is currently very little data available on the harms of third hand smoke. It is also going to be quite hard to study given that for the opportunity in most settings to be exposed to third hand smoke means there normally would need to have been a smoker in the vicinity and thus it would be difficult to differentiate the effects of second hand smoke.

“This study is again providing similar evidence to what has already been published showing that this process takes place, and shows us how widely our exposure to these chemicals might be. This study is laboratory based so adds to our knowledge of exposure but not of the health risks.

“Previous studies have shown children are exposed to third hand smoke, more so than adults, and can be found in surprising places e.g. in neonatal intensive care incubators which have clearly come from third hand smoke. A previous UK study assessing the exposure of third hand smoke in smokers’ houses suggested there would be an increased risk of cancer (possibly 1 per 1000 exposed). It is likely the risks will be higher in these settings e.g. smokers houses and cars. Another potential risk is in parents who smoke and then hold their babies. The size of the baby means it will be close to their clothing that will be emitting these toxic chemicals.

“I do not know of current evidence showing so but it would be reasonable to assume a similar situation would likely occur with vaping, though the range of harmful chemicals would likely be more limited given there are fewer toxins released than with tobacco smoking.”


Prof Peter Hajek, Director of the Tobacco Dependence Research Unit, Queen Mary University of London (QMUL), said:

“The article itself concerns aerosol formation and rightly avoids any mention of harm, toxicity or any health effects. It is the dose that makes the poison and to make any statements on this, the exposures detected here would need to be compared with e.g. air quality or occupational health standards. As is increasingly common however in publicity hungry press releases, the claims about health hazards and toxicity suddenly appear out of thin air. The study documents no health risks, but without such claims, the findings are not newsworthy.”


* ‘Thirdhand smoke uptake to aerosol particles in the indoor environment’ by Peter DeCarlo et al. will be published in Science Advances on Wednesday 9 May 2018.


Declared interests

None received.

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