E-cigarette vaping, chemical composition and lung toxicity

Electronic cigarettes (e-cigarettes) have gained incredible popularity in the US and world market.  Since its first introduction in US commerce in the mid 2000s, sales in the e-cigarette industry increased to $3.5 billion in 2015.  The study of the health effects of these products is complicated by the fact there are hundreds (and perhaps thousands) of e-cigarette devices and thousands of e-liquids (liquids used in the e-cigarette devices) available to consumers.  New e-cigarettes, such as third generation devices or open-tank systems, have increased the functionality for consumers by allowing any e-liquid to be added to the device and offering variable power settings, which can increase the temperature of the device, as well as the output of aerosol and delivery of nicotine.  While third generation e-cigarette devices have gained popularity over prior device generations, it is not well understood how varying device settings and e-liquid formulations may influence chemical exposure and respiratory health effects in comparison to smoking conventional tobacco cigarettes.  The purpose of this research is to advance the understanding of the hazardous chemical profile of e-cigarette “smoke” (defined here as a mixture of vapor and aerosol particles) and the implications for respiratory health effects. This research will assess how e-cigarette device and e-liquid (liquid used in e-cigarette devices) parameters influence e-cigarette smoke chemistry, specifically the production of hazardous thermal degradation products and particle size distribution.  Inhalation toxicology studies will evaluate how differences in e-cigarette vapor/aerosol characteristics under varying e-cigarette device and e-liquid parameters influence effects in the respiratory tract, which will provide a better understanding of the mechanisms by which e-cigarette smoke may impact the respiratory system in comparison to conventional cigarette smoke.