Researchers at the University of California, Riverside, found that heating propylene glycol, the main ingredient in most e cigarette liquids, can produce two toxic chemicals, methylglyoxal and acetaldehyde, which damage lung cells. Using The combination of propylene glycol and vegetable glycerin e cigarette aerosols induces airway inflammation and mucus hyperconcentration Scientific Reports Les E Cigarettes Vaping water: Is it a safe alternative to traditional e liquid? Decouverte des meilleurs e liquides francais dans le magasin de cigarettes electroniques a Lorient