Nicotine emissions from electronic cigarettes: Individual and interactive effects of propylene glycol to vegetable glycerin composition and device power output

The power output of e-cigarettes varies considerably, as does the composition of liquids used with these products. Most e-cigarette liquids contain two primary solvents: propylene glycol (PG) and vegetable glycerin (VG). The primary aim of this study was to examine the extent to which PG and VG composition and device power interact with each other to influence e-cigarette nicotine emissions.

Aerosols were generated using a 2nd generation e-cigarette and an automatic smoking machine. Nicotine was measured in aerosols, via gas chromatography, produced from three solutions containing pure PG, pure VG, or a mixture of both solvents (50:50) across three different power settings (4.3, 6.7, and 9.6 W).

At the lowest power setting, nicotine yield increased significantly as more PG was added to the solution. However, as device power was increased, differences in nicotine yield across liquids became less pronounced. At the highest power setting (9.6 W), nicotine yields did not differ across the three liquids examined.

The present study demonstrated that the extent to which e-cigarette liquid PG and VG composition influences nicotine emissions is dependent on device power. Thus, device power may influence e-cigarette nicotine emissions to a greater degree relative to solvent concentrations.