Secondhand exposure to vapors from electronic cigarettes

Abstract

Introduction: Electronic cigarettes (e-cigarettes) are designed to generate inhalable nicotine aerosol (vapor). When an e-cigarette user takes a puff, the nicotine solution is heated and the vapor is taken into lungs. Although no sidestream vapor is generated between puffs, some of the mainstream vapor is exhaled by e-cigarette user. The aim of this study was to evaluate the secondhand exposure to nicotine and other tobacco-related toxicants from e-cigarettes.

Materials and methods: We measured selected airborne markers of secondhand exposure: nicotine, aerosol particles (PM(2.5)), carbon monoxide, and volatile organic compounds (VOCs) in an exposure chamber. We generated e-cigarette vapor from 3 various brands of e-cigarette using a smoking machine and controlled exposure conditions. We also compared secondhand exposure with e-cigarette vapor and tobacco smoke generated by 5 dual users.

Results: The study showed that e-cigarettes are a source of secondhand exposure to nicotine but not to combustion toxicants. The air concentrations of nicotine emitted by various brands of e-cigarettes ranged from 0.82 to 6.23 µg/m(3). The average concentration of nicotine resulting from smoking tobacco cigarettes was 10 times higher than from e-cigarettes (31.60±6.91 vs. 3.32±2.49 µg/m(3), respectively; p = .0081).

Conclusions: Using an e-cigarette in indoor environments may involuntarily expose nonusers to nicotine but not to toxic tobacco-specific combustion products. More research is needed to evaluate health consequences of secondhand exposure to nicotine, especially among vulnerable populations, including children, pregnant women, and people with cardiovascular conditions.

Figure 1.

Effect of e-cigarette brand on nicotine (left) and aerosol particle (right) concentration in the air inside exposure chamber.

Figure 2.

Comparison of indoor air nicotine (left) and aerosol particle (right) concentrations released from e-cigarette with background values and tobacco cigarette smoking.Note. ^aVapor generated with smoking machine (Study 1); ^bVapor exhaled by users (Study 2).

Figure 3.

Changes of aerosol particle PM_2.5 concentrations during experiment of e-cigarette use and tobacco cigarette smoking in exposure chamber.