Conflict of interest statement: R.P. is a full-time employee of the University of Catania, Italy. In relation to his work in the area of tobacco control, R.P. has received lecture fees and research funding from Pfizer and GlaxoSmithKline, manufacturers of stop-smoking medications. He has also served as a consultant for Pfizer, Global Health Alliance for treatment of tobacco dependence, Electronic Cigarette Industry Trade Association, UK, and Health Diplomats. Lecture fees from a number of European electronic cigarette industry and trade associations (including FIVAPE in France and FIESEL in Italy) were directly donated to Vaper Advocacy no-profit organizations. Although no research was ever funded by the industry, support contributing to publication/open access costs of the following papers was received by the e-cig/e-liquid industry: Happy Liquid for https://www.ncbi.nlm.nih.gov/pubmed/28337155; Ritchy Europe for https://www.ncbi.nlm.nih.gov/pubmed/27845734; Cuts Ice e-Liquid Laboratories for https://www.ncbi.nlm.nih.gov/pubmed/28477286; and VDLV e-Liquids for https://www.ncbi.nlm.nih.gov/pubmed/28362360. R.P. is currently Scientific Advisor for LIAF, Lega Italiana Anti Fumo (Italian acronym for Italian Anti-Smoking League) and Head of the European Technical Committee for standardization on'Requirements and test methods for emissions of electronic cigarettes' (CEN/TC 437; WG4).