“When you came to our school you mentioned ‘third-hand aerosol’. I was trying to tell my friend about it but couldn’t remember everything you said. What is it exactly and how dangerous is it?”
Third-hand aerosol is the chemical residue left behind after someone has vaped. We see something similar when someone has smoked – nicotine and other chemicals and particles staying around and building up on surfaces over time. We call this ‘third-hand smoke’. People have been smoking for a long time so we know a great deal about the risks associated with third-hand smoke. Vaping is a new phenomenon, however, and the effects of third-hand exposure to the aerosol produced by these devices are not fully understood.
It’s important to note that what’s produced by e-cigarettes is an ‘aerosol’ and not a ‘vapour’. A vapour is a gaseous state of something that is normally a liquid, containing nothing else but the gas itself. An aerosol is a mixture of tiny liquid particles suspended in a gas. The aerosols produced by vaping can leave tiny droplets behind and these can contain a range of chemicals and substances.
The residue produced after vaping has been found on fabrics such as clothing, couches and curtains, surfaces such as walls and floors, as well as human skin and hair. Like third-hand smoke, it can also build up over time, particularly in places where people vape regularly, whether that be in rooms or buildings, or even a vehicle.
As with third-hand smoke, babies and children are believed to be the most susceptible to the effects of third-hand aerosol. This is due to their thinner skin and age-specific behaviours, such as crawling on surfaces and placing objects in their mouth, resulting in them being more likely to be exposed to the residue. Smaller family pets could also be at greater risk, with cats particularly at risk due to their oral grooming behaviours. Much more research is needed for us to have a better understanding of the risks associated with vaping, not only for the person using the device but also for those around them. What is clear is that if people are going to choose to vape, they should do it outdoors and away from others.
First published: January 2025
