Selected harmful or potentially harmful constituent yields in the aerosol of commercial closed systems electronic cigarettes
Over the past few years, electronic cigarettes have rapidly evolved and have been introduced in multiple markets across the world. They are thought to be a potentially less harmful alternative to cigarettes, as they heat a liquid to generate the aerosol instead of combusting tobacco. Electronic cigarettes have different designs, with closed systems (such as cartridges), open systems, and mods. The aim of this study was to examine the aerosol emissions of various cartridge e-cigarettes from different markets. Our efforts were mainly focused on carbonyls, tobacco-specific nitrosamines, metals, benzene, benzo[a]pyrene, and 1,3-butadiene. The study was conducted in three waves from 2015 to 2018, with 18 device and liquid combinations. For each product, three replicates of the devices were used to test product variability and the tests were conducted until total liquid depletion to test the products’ consistency. To put the results into perspective, the aerosol constituents of e-cigarettes were compared with smoke from the 3R4F reference cigarette. Many of the harmful or potentially harmful constituents tested were not quantifiable or were below the levels of air blanks. For the examined cartridge systems, the carbonyl emissions were detectable, with formaldehyde being the most variable. Compared with other e-cigarette system designs, formaldehyde in cartridges showed a considerable reduction compared with the emissions from 3R4F mainstream smoke. Several of the products analysed were also tested under diverse conditions (different puffing regimes and analytical puffing machine orientation). The obtained results indicated an overall consistency of products across the various conditions, as the emissions did not change greatly.