Clear The Air News Tobacco Blog Rotating Header Image

March 20th, 2015:

Harmful substances in e-cigarettes assessed

While e-cigarettes are less harmful to health than tobacco cigarettes, the vapour from an e-cigarette contains substances and chemical impurities in concentrations that could be detrimental to health. This is the result of a recent study carried out by RIVM in the Netherlands .

Electronic cigarettes vaporise a liquid containing nicotine and flavourants. The harmful substances in e-cigarettes include nicotine, propylene glycol and glycerol, aldehydes, nitrosamines and metals. When inhaled, these substances can lead to irritation and damage to the respiratory tract, heart palpitations and an increased risk of cancer. These health impacts are less severe that those associated with smoking tobacco.

Composition e-fluids

The study included measurement, risk assessment and a survey of e-cigarette users. The composition of many e-fluids available in the Netherlands, and the resulting vapour were found to vary considerably. In some cases, the amount of nicotine in the vapour was not in line with that stated on the package. The concentrations of some substances in the vapour were higher than in the fluid, and some substances were only formed when vaporised. Aldehydes, for instance, only formed when the liquid was heated and metals were released from the atomiser. Propylene glycol and glycerol are carrier liquids for nicotine and flavourants.

Use e-cigarette

The study found that people smoke e-cigarettes mainly because they presumed e-cigarettes to be less harmful than tobacco cigarettes and helped them to stop smoking. Refillable cigarettes are the most popular of the main brands and models available in the Netherlands. Virtually all users (vapers) had smoked tobacco before using e-cigarettes and most continued to smoke tobacco as well as e-cigarettes. Large behavioural differences between vapers were reported, for instance, in the number of puffs reported per day.
risks of e-cigarettes

The study was carried out for the Ministry of Health, Welfare and Sport because of the rapid growth in the number of e-cigarette users and uncertainties about the health effects. The risk to users associated with substances in the vapour inhaled was assessed in this study and later in the year, RIVM will assess the potential health effects of substances present in the exhaled vapour. An abridged English version of the study will be published shortly on our website.

(Report in Dutch)


Electronic cigarettes, or e-cigarettes, vaporize a liquid that often contains nicotine and flavorants. Although e-cigarettes are less harmful than tobacco cigarettes, the e-cigarette vapor contains several ingredients and chemical impurities such as nicotine, propylene glycol, glycerol, aldehydes, nitrosamines and metals at concentrations that can be detrimental to health. Inhalation of these substances can lead to irritation of and/or damage to the respiratory tract, palpitations and an increased risk of developing cancer. These health effects are, however, less severe than those associated with smoking tobacco, which include lung cancer, heart attack and stroke, pulmonary emphysema, chronic obstructive pulmonary disease (COPD), and oral, tongue, esophageal, stomach and bladder cancer.

The Dutch National Institute for Public Health and the Environment (RIVM) performed a survey on e-cigarette users, performed measurements and assessed the risks. The study was performed on behalf of the ministry of Health, Welfare and Sport (VWS) because of the substantial increase in e-cigarette users, and the uncertainties surrounding the health effects of e-cigarette use. In this study, the RIVM assessed the possible health risks associated with exposure to the substances in e-cigarette vapor. In 2015, the RIVM will assess the possible health effects resulting from exposure to the compounds present in exhaled vapor.

Findings regarding users
The survey on Dutch e-cigarette users showed that the main reasons for e-cigarette use were that people presumed it to be less harmful than regular cigarettes, and to help them to quit smoking. Of the many brands and models available, refillable e-cigarettes were the most popular. Virtually all users had smoked tobacco prior to using e-cigarettes and most were dual users continuing to smoke tobacco in addition to e-cigarettes. There were large behavioral differences between ‘vapers’, for instance there were large variances in the number of puffs reported per day.

E-liquid and vapor composition Considerable differences were observed in the composition of different kinds of e-liquid available on the Dutch market and that of the resulting vapor. In some cases, the amount of nicotine in the e-liquid did not match the declared amount on the packaging. The concentration of some compounds was found to be higher in the vapor than in the liquid. Aldehydes are formed when the e-liquids are heated, and metals are released from the atomizer. Propylene glycol and glycerol function as a ‘carrier liquid’ for nicotine and flavorants.