More evidence that e-cigs cause substantial air pollution in real environments and inflammatory processes in vapers

Wolfgang Schober and colleagues from the Bavarian Health and Safety Authority just published a nice study that measures indoor air pollution cased by e-cigarettes in a realistic environment in which they configured a room to be configured and ventilated like a cafe in which 3 people vaped e-cigarettes over a 2 hour period.  They measure both air quality in the room as well as the presence of various chemicals in the people consuming the e-cigarettes.
 
In terms of air pollution, the found substantial increases in fine particles (mean of 197 mcgh/m3, compared to a mean of 6 mcg/m3 under control conditions when no one was vaping.  They also found a 20% increase in carcinogenic polycyclic aromatic hydrocarbons.
 
They also found increased measures of inflammatory processes in the people using e-cigarettes, which could indicate lung irritation.  (Increase levels of inflammation could also have effects on blood and blood vessels in ways that increase the risk of triggering a heart attack.)
 
Here is the abstract of the paper:

Despite the recent popularity of e-cigarettes, to date only limited data is available on their safety for both users and secondhand smokers. The present study reports a comprehensive inner and outer exposure assessment of e-cigarette emissions in terms of particulate matter (PM), particle number concentrations (PNC), volatile organic compounds (VOC), polycyclic aromatic hydrocarbons (PAH), carbonyls, and metals. In six vaping sessions nine volunteers consumed e-cigarettes with and without nicotine in a thoroughly ventilated room for two hours. We analyzed the levels of e-cigarette pollutants in indoor air and monitored effects on FeNO release and urinary metabolite profile of the subjects. For comparison, the components of the e-cigarette solutions (liquids) were additionally analyzed. During the vaping sessions substantial amounts of 1,2-propanediol, glycerine and nicotine were found in the gas-phase, as well as high concentrations of PM2.5 (mean 197 mcg/m3). The concentration of putative carcinogenic PAH in indoor air increased by 20% to 147 ng/m3, and aluminum showed a 2.4-fold increase. PNC ranged from 48,620 to 88,386 particles/cm3 (median), with peaks at diameters 24–36 nm. FeNO increased in 7 of 9 individuals. The nicotine content of the liquids varied and was 1.2-fold higher than claimed by the manufacturer. Our data confirm that e-cigarettes are not emission-free and their pollutants could be of health concern for users and secondhand smokers. In particular, ultrafine particles formed from supersaturated 1,2-propanediol vapor can be deposited in the lung, and aerosolized nicotine seems capable of increasing the release of the inflammatory signaling molecule NO upon inhalation. In view of consumer safety, e-cigarettes and nicotine liquids should be officially regulated and labeled with appropriate warnings of potential health effects, particularly of toxicity risk in children.

The paper is Schober, W., et al., Use of electronic cigarettes (e-cigarettes) impairs indoor air quality and increases FeNO
levels of e-cigarette consumers. Int. J. Hyg. Environ. Health (2013), http://dx.doi.org/10.1016/j.ijheh.2013.11.003