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The E-cigarette market is a multi-billion pound industry and one which is only continuing to grow.

For many “vaping” is now a part of everyday life and it’s rare to walk down a busy street these days without seeing somebody using one of the devices.

Medical experts believe vaping is 95% safer than smoking a conventional cigarette - but there is still some uncertainty surrounding e-cigarettes and what the possible side effects could be.

And one theory is that e-cigarettes could have contributed towards a little known condition called “popcorn lung”.

But what is popcorn lung?

Popcorn lung is a slang term used for a condition called bronchiolitis obliterans (B0).

BO is caused by inhaling chemicals that scar the lungs and in effect stop them from working properly, by reducing their capacity and efficiency.

The symptoms of BO include a dry cough, shortness of breath, wheezing, and feeling tired.

The condition is similar to Chronic Obstructive Pulmonary Disease (COPD) and is commonly diagnosed as this, as to diagnose BO a lung biopsy is required.

One of the inhaled chemicals associated with the cause of popcorn lung is Diacetyl.

Diacetyl is a chemical used in many processed foods to impart a buttery or creamy flavour.

In the past it was used by manufacturers to give popcorn its buttery taste and in 2002 eight cases of irreversible lung disease were documented in people who had worked at a Missouri popcorn factory between 1992 and 2000. This is where the condition’s name is derived from.

But as well as being found in foods, the chemical has also been found in the flavouring of e-liquids in e-cigarettes - before it was banned in 2016 under EU law.

So, does smoking e-cigarettes cause popcorn lung?

An expert believes not - and this is why.

According, Dr Lion Shahab - a senior lecturer in health psychology at the University College of London - the level of Diacetyl found in some e-liquids is actually a lot lower than in an actual cigarette.

He said: “Diacetyl and also acetyl propionyl have been linked to popcorn lung, so-called because it is a flavouring agent that gives popcorn a buttery taste and has been linked to a lung disease Bronchiolitis Obliterans, which is not dissimilar to COPD in those exposed to it through work.

(Image: PA Photo/thinkstockphotos)

“However, while some flavourings (not all) found in e-liquid contain these chemicals, it is at levels much lower than that found in conventional cigarette smoke.

“Exposure for smokers is at least 85 times higher.

“But, what’s more, there is no reliable link between exposure to these chemicals through smoking conventional cigarettes and popcorn lung.

“So, given that exposure to these chemicals is much lower in e-cigarette users and only present in some, not all, e-liquids and that even higher levels of exposure (through cigarette smoking) are not reliably linked to Bronchiolitis obliterans, it is very unlikely that e-cigarette use leads to popcorn lung.

(Image: PA Photo/thinkstockphotos)

“It is a theoretical, not actual, risk as also shown by the fact that there is not a single case in which e-cigarette use has in fact been linked to popcorn lung in literature.”

*Diacetyl was banned in e-liquids and e-cigarettes in the UK, in 2016, under the EU Tobacco Products Directive.

For advice on stopping smoking go to: https://quitnow.smokefree.nhs.uk/