London, Sep 12: E-cigarette liquids contain one substance classified as a health risk, such as those capable of causing asthma and allergy symptoms, researchers have found.
According to the United Nations classification system, every liquid they tested contained at least one substance that has some level of risk to health.
These included methyl cyclopentanolone (found in 26.3 per cent of samples) and a-ionone (found in 8.7 per cent of samples), both of which “may cause allergy or asthma symptoms or breathing difficulties if inhaled”, according to their classification.
Other substances, such as menthol (42.9 per cent of samples), ethyl vanillin (16.5 per cent of samples) and acetyl pyrazine (8.2 per cent of samples), are classified as “able to cause respiratory irritation”.
“Our research reveals that e-cigarette liquids on sale have ingredients that are potential respiratory irritants,” said Constantine Vardavas from the University of Crete.
“This means that they are substances which irritate the airways according to previous research and international classification standards.”
A random sample of e-cigarette liquids was selected for research from popular brands on sale in nine European countries.
It included a variety of flavours and nicotine strengths.
In a study researchers surveyed more than 30,000 people, e-cigarette respiratory symptoms such as a persistent cough, wheezing and coughing up mucus as much as those who smoke conventional cigarette.