Background. Since their introduction, electronic cigarette (EC) use has increased substantially. Perhaps most concerning is the increased use amongst adolescents. Many e-cigarette users believe that electronic cigarettes are safer than conventional cigarettes [1]. However, the toxicities of electronic cigarettes, including those in the lung, are relatively poorly studied. Notably, early studies suggest that electronic cigarettes are not harmless. The fine and ultra-fine particles could deposit in the lungs and lead to harm. Animal studies of electronic cigarettes have been associated with a number of pulmonary toxicities, including increased inflammation and oxidative stress in the lung [2] as well as impaired pulmonary immunity [3, 4]. EC vapour reduces indoor air quality by increasing the concentrations of particulate matter, particle number concentrations, polycyclic aromatic hydrocarbons (PAH) which are known carcinogens [5]. Early studies on cardiovascular function also suggests harm from the constituents of EC vapour such as the direct effects of nicotine, carbonyls as well as fine and ultrafine particles [6].