E-cigarettes might not be as harmless as you think.
While some manufacturers claim they only give off water vapour, new research suggests it's likely e-cigarettes actually pose a passive risk to children and pregnant women -- just like traditional smokes.
"The risk from passive exposure to e-cigarettes is likely to be less than conventional cigarettes, but bystanders can be exposed to numerous pollutants above background levels and in concentrations that can be harmful to health," says lead author Isabel Hess, senior policy analyst at the New South Wales Health.
"E-cigarette vapour can contain elevated levels of nicotine, fine particulate matter, glycerine, propylene glycol, formaldehyde and metals."
Even at low concentrations, these ingredients can lead to heart and lung disease, stunt brain and lung development and cause cancer.
Dr Hess says much more research is needed to discover the full risks of inhaling e-cigarette vapour.
"Based on the evidence available to date we can say that passive exposure to e-cigarettes has the potential to impact on people's health."
The new findings conflict with a study last year which found smoking e-cigarettes -- also known as vaping -- was as safe as breathing air. That research, mind you, was funded by British American Tobacco, one of the biggest cigarette manufacturers in the world.
The Ministry of Health here says e-cigarettes are "likely to be less toxic than conventional cigarettes", but more research is needed.
The findings are published in journal Public Health Research & Practice.