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December 1st, 2016:

National Cancer Institute – The Economics of Tobacco and Tobacco Control

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Scientists say flavoured e-cigarettes 250 times more toxic than recommended safety level

According to a recent study, some additives break down into toxic compounds that dramatically exceed guidance for occupational health when converted into vapour

One puff of a flavoured e-cigarette can expose a smoker to cancer causing chemicals that are more than 250 times the recommended safety level, say scientists.

When converted into a vapour, some additives break down into toxic compounds that dramatically exceed guidance for occupational health, according to the study.

Previous research has identified the ingredients in vapour flavourings, but very little has been done to determine what happens when they are transformed inside the device.

A growing body of evidence has shown the heat that converts e-liquids into vapour decomposes its contents.

This chemical breakdown produces toxic aldehydes, including formaldehyde, during the rapid heating process that happens inside the devices.

Aldehydes are members of a class of organic chemical compounds used in the textile, food, rubber, plastics, leather, chemical and health care industries.

So Dr Andrey Khlystov and colleague analysed vapours created from both unflavoured and flavoured e-liquids loaded into three popular types of e-cigarettes.

The tests for 12 different aldehydes showed the amount of potentially harmful compounds varied widely across e-liquid brands and flavours.

But in general one puff of flavoured vapour contained levels of aldehydes 1.5 to 270 times above the safe thresholds for occupational exposure set by the American Conference of Governmental Industrial Hygienists.

Vapours from unflavored e-liquids contained aldehydes at significantly lower levels, reports the journal Environmental Science & Technology.

Dr Khlystov, of the Desert Research Institute, Nevada, said: “The growing popularity of electronic cigarettes raises concerns about the possibility of adverse health effects to primary users and people exposed to e cigarette vapours.

“E-cigarettes offer a very wide variety of flavours, which is one of the main factors that attract new, especially young, users.

“How flavouring compounds in e-cigarette liquids affect the chemical composition and toxicity of e-cigarette vapors is practically unknown.

“Although e-cigarettes are marketed as safer alternatives to traditional cigarettes, several studies have demonstrated formation of toxic aldehydes in e-cigarette vapours during vaping.”

Sales of e-cigarettes have been rising steadily since they first went on sale in the UK, in 2007. They are now used by nearly three million people in the UK.

In the past few years, they have replaced nicotine patches and gum to become the most popular choice of smoking cessation aid in England.

It is illegal to sell e-cigs to under-18s in the UK – but their use among teenagers is growing.

Use of e-cigarettes among under-18s rose from 5 per cent in 2013 to 8 per cent in 2014 – and some experts are concerned that they may act as a ‘gateway’ to smoking tobacco.

Added Dr Khlystov: “So far, aldehyde formation has been attributed to thermal decomposition of the main components of e-cigarette e-liquids (propylene glycol and glycerol), while the role of flavouring compounds has been ignored.

“In this study, we have measured several toxic aldehydes produced by three popular brands of e-cigarettes with flavoured and unflavoured e-liquids.

“We show that, within the tested e-cigarette brands, thermal decomposition of flavouring compounds dominates formation of aldehydes during vaping, producing levels that exceed occupational safety standards.

“Production of aldehydes was found to be exponentially dependent on concentration of flavouring compounds.

“These findings stress the need for a further, thorough investigation of the effect of flavouring compounds on the toxicity of e-cigarettes.”

E-cigarette liquids are marketed in nearly 8,000 different flavours, according to a 2014 report by the World Health Organisation .

Recent reports show many of these flavours, such as Gummy Bear, Tutti Fruity, and Bubble Gum, are especially appealing to teens and kids, encouraging them to use the devices.

The Electronic Cigarette Industry Trade Association said the results reflected “dry puff”, when too little liquid reaching the heating element causes overheating.

It added: “Levels like these are extremely unlikely to reflect real-world exposures.”