Electronic cigarettes may involuntarily expose non-users to significant amounts of nicotine when used indoors, according to a new study now available online ahead of print in the journal Nicotine and Tobacco Research (doi: 10.1093/ntr/ntt203). The findings also showed that emissions of nicotine from e-cigarettes were significantly lower than those of conventional tobacco cigarettes.
“To our knowledge, this is one of the first studies to measure the air concentrations of nicotine and volatile organic compounds and compare the emissions from electronic and conventional tobacco cigarettes,” said the study's lead author, Maciej Goniewicz, PhD, PharmD, Assistant Professor of Oncology in Roswell Park Cancer Institute's Department of Health Behavior. “Our data suggest that secondhand exposure to nicotine from e-cigarettes is on average 10 times less than from tobacco smoke. However, more research is needed to evaluate the health consequences of secondhand exposure to nicotine from e-cigarettes, especially among vulnerable populations including children, pregnant women, and people with cardiovascular conditions.”
The researchers conducted two studies to assess emissions from e-cigarettes: the first was designed to evaluate major factors that might affect exposure patterns and used a smoking machine in controlled exposure conditions to compare vapors from three different e-cigarette brands; and the second was to compare emissions from e-cigarettes and cigarette smoke generated by users of both products. Among the findings:
- Nicotine was detected in the air during all experiments where e-cigarette vapor was generated with the smoking machine and released into the exposure chamber;
- The average concentration of nicotine resulting from smoking tobacco cigarettes was 10 times higher than from e-cigarettes;
- Aerosol particles were detected in the air during all experiments with vapor generated with the smoking machine and released into the exposure chamber;
- The average concentration of aerosol particles resulting from smoking tobacco cigarettes was seven times higher than from e-cigarettes;
- There were no changes in carbon monoxide concentration after using e-cigarettes in both studies—however, smoking of two tobacco cigarettes in the second study increased the concentration in the exposure chamber on average by two to three parts per million (volume/volume);
- Toluene was the only volatile organic compound (VOC) detected in the exposure chamber during the study with machine-generated e-cigarette vapor, and no statistical difference was found between average toluene concentrations after release of e-cigarette vapor and baseline values;
- Smoking two tobacco cigarettes increased the concentration of four VOCs: toluene, ethylbenzene, m p-xylene, and o-xylene; and
- Compared with that in smoking e-cigarettes, the average concentration after smoking tobacco cigarettes was 3.5-fold higher for toluene.
The study also notes that future research is needed to explore emissions and exposure to other toxins and compounds identified in e-cigarettes (such as formaldehyde, acetaldehyde, and acrolein), but not reported in this study, as well as research to investigate whether the vapor from e-cigarettes is deposited on surfaces to form “third-hand” e-cigarette vapor. And, data are also needed to determine whether secondhand exposure to e-cigarette vapors results in reinforcement of nicotine addiction.