E-CIGARETTES: DEVICES THAT ARE 95 PER CENT SAFER THAN TOBACCO

Q: What are e-cigarettes?

A: E-cigarettes, also known as personal vaporisers (PV) or an electronic nicotine delivery system (ENDS), give users a nicotine hit without burning tobacco leaves.

When the user sucks on the e-cigarette, liquid nicotine is vaporised and absorbed through the mouth.

When they breathe out, a plume of what appears to be smoke is emitted but it is actually largely water vapour.

A battery-powered heating coil heats the liquid to form the vapour, with some of the designs involving a pressure sensor that is activated by the user taking a puff, while others have a button to heat them automatically.

E-cigarettes, also known as personal vaporisers, give users a nicotine hit without burning tobacco leaves

Q: How popular are they?

A: Inventor Hon Lik was the first to have his idea patented in his native China in 2003, and it has since become an industry worth around £2 billion. Anti-smoking group Ash estimates there are now 2.6 million vapers in the UK.

Q: Are they all the same?

A: No. There are a huge variety of products on the market, and hundreds of different flavours.

Cigalikes were the first kind of e-cigarettes, designed to look as much like a traditional cigarette as possible in order to make them more appealing to smokers.

They use either disposable or replaceable cartridges.

Because they are so small they can only be fitted with low-capacity batteries and need to be recharged more often than the larger tank-type e-cigarettes that were later developed and which can be refilled with 'e-liquid'.

Cigalikes are often regarded as the 'entry level' to vaping, before users move on to larger models.

Q: What are the health risks?

A: Numerous studies have been carried out, but as e-cigarettes are such a new product they can only look at the short-term effects. Public Health England (PHE) said that experts have calculated vaping to be at least 95 per cent less dangerous than smoking - or alternatively that smoking is 20 times more dangerous than using e-cigarettes.

While cigarettes contain carcinogens and other toxic chemicals contained in tar from tobacco, e-cigarettes do not burn tobacco and so avoid delivering these substances.

The main health issues surrounding e-cigarettes concern other ingredients, contaminants and by-products, which can generate some toxicants - but these are at the very low levels found in the air that people generally breathe.

Q. Should people switch immediately?

But while e-cigarettes are far less dangerous than conventional cigarettes, health experts are not encouraging people to take up the habit for the sake of it.

The emergence of e-cigarettes has given way to fears that they will act as a gateway to smoking conventional cigarettes among those who have never smoked - particularly children - but there is no evidence to support this.

Although many youngsters report having tried vaping, as Professor Peter Hajek, director of the Tobacco Dependence Research Unit at Queen Mary, University of London, and a co-author of the PHE report, said: 'People who are attracted to e-cigarettes are the same people who are attracted to smoking.