Is a harmful level of nicotine exhaled when vaping?
The vape industry has exploded in the last few years. Walking down the street you might be able to smell that someone is vaping close by, this means you are inhaling their second-hand vapour or aerosol. Although we have a pretty good understanding of the health impacts of second-hand smoke from cigarettes, the potential effects of second-hand vapour are less clear.
What is in second-hand vapour? If chemicals such as nicotine are found in second-hand vapour, are they at high enough levels to do damage to people close by? We asked 5 experts in smoking, chemistry, cell biology and public health, ‘Is a harmful level of nicotine exhaled when vaping?’, here is what they said…
Is a harmful level of nicotine exhaled when vaping?
What is vaping?
‘Vapes’ or ‘e-cigarettes’ are battery-powered devices that heat up liquids to create an aerosol that you inhale. The vaping and e-cigarette industry was valued at over 17 billion US dollars in 2021 and about 82 million people regularly vaped in 2021.
Here we will refer to people who regularly vape as ‘vapers’ or ‘primary vapers’, and those who inhale what vapers exhale as ‘secondary vapers’. The gas that is exhaled when vaping is called ‘secondhand vapour/aerosol’.
Is nicotine exhaled when vaping?
Professor Mathieu Morissette, an expert in cell biology from Laval University in Canada, says “Vapes do exhale nicotine and it can remain in suspension in the room and be detected and quantified”. Dr Neal Benowitz, an expert in smoking and medicine from California University in the USA, says “Nicotine that is exhaled quickly leaves particles and enters the environment as a gas, then deposits on surfaces. Nicotine can be found on surfaces in homes and business where people vape. Non-nicotine users who lives with vapers have measurable but low levels of cotinine (the main metabolite of nicotine) in their blood.”
It is not clear exactly how much nicotine is exhaled due to the many variables involved. Dr Benowitz says “The amount of nicotine varies tremendously by the type of device and the behaviour of the vaper. High power devices generate large amounts of aerosol, much of which may be exhaled, such as in cloud chasing. Low power devices generate small amounts of aerosol, and very little is exhaled.” Professor Morissette adds that “Variables affecting the amount of nicotine in the air are/can be severals: nicotine concentration in the e-liquid (from 0 to >30mg/ml); vaping intensity; room size; ventilation; distance between primary and secondary vaper; etc”
Is the amount of nicotine in vapour harmful?
Dr Morissette says “Can it be harmful? Acutely, very unlikely. However, chronic nicotine exposure does have adverse effects, especially in young individuals. We also have to consider that secondary vapers could, over time, develop low grade nicotine addiction that could make them more susceptible to start vaping or smoking. However, this remains a hypothesis.”
Professor Lynne Dawkins, an expert in public health and addiction from London South Bank University in the UK, says “Detectable levels of nicotine have been found in e-cigarette vapour generated in the laboratory but these were 10 times lower than levels measured in tobacco smoke (3.32 μg /m3 compared with 31.6 μg /m3). Moreover, under normal usage conditions, the user would inhale most of this vapour, so exhaled levels would be even lower. So, using an e-cigarette in an indoor environment may expose others to low levels of nicotine but this is unlikely to be harmful.”
Is there anything else in secondhand vapour that could be harmful?
Professor Dawkins says “Nicotine actually carries minimal health risks - it's the thousands of other chemicals in tobacco smoke [from cigarettes] that are responsible for almost all the harms. There is clear evidence that second hand smoke is harmful but this is not because of the nicotine.”
Perhaps the secondhand vapour from vapes could also be dangerous, but not because of nicotine. Other things found in secondhand aerosols from vapes include heavy metals, cancer-causing compounds such as benzene and fine particles.
Although these chemicals are dangerous when inhaled at high doses, secondhand vapour only contains very small amounts. Professor Dawkins says that “In relation to e-cigarette vapour, in a recent evidence review of e-cigarettes commissioned by Public Health England it was concluded that there is no evidence that e-cigarette vapour is harmful to bystanders.”
Is there uncertainty around how harmful secondhand vapour is?
Dr Rebecca Williams, an expert in public health from the University of North Carolina at Chapel Hill in the USA, believes that “There is insufficient research evidence to answer this question at this time, particularly in a general sense without context (number of people vaping, size of enclosed/unenclosed space, proximity to non-vaping people, how you define 'harmful level of nicotine', etc).” She says “I suspect that as more and more research on this topic is published, the evidence for secondhand e-cigarette vapour being a health risk to non-vapers will grow substantially.”
Current research suggests that second-hand vapour does not contain a harmful level of nicotine, but more research is needed.
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