Passive smoking, or 'secondhand smoke,' occurs when an individual inhales the toxins and chemicals released from burning cigarettes, either exhaled by someone actively smoking or from smoke generated by the smoldering tip of a lit cigarette. Considerable research has been done regarding the effects of combustible cigarette smoke, and laws have been put in place over the years to help reduce its decidedly harmful impact on the public population.

As vaping became a popular alternative to smoking, many laws regarding secondhand smoke were hastily amended to include secondhand vapor as if the risk of exposure to bystanders was comparable to that of smoke. This, however, has sparked debate regarding the safety of vapor exhaled from e-cigarettes - is it really as dangerous as these law changes imply?

Secondhand Exposure to Vapor From Electronic Cigarettes

In 2014, an early research study was conducted that focused on secondhand exposure to nicotine and other emissions generated by e-cigarettes. This was done by measuring airborne markers of secondhand vapor and secondhand smoke including nicotine, aerosol particles, carbon monoxide, and volatile organic compounds. Vapor samples were taken from three brands of e-cigarettes that were used in a controlled exposure smoking machine. Also compared was secondhand vapor and smoke created by five participants who identified as dual users.

This research focused on two studies of e-cig emissions, the first of which focused on factors that could affect exposure patterns. Vapor was generated from three models of e-cigs and released into an exposure chamber. Researchers found that the nicotine levels in the e-cigs varied based on their labels, showing that even though the liquid was marketed as 18mg/ml it ranged from 11mg/ml to 19mg/ml. Evaluations of the emissions were taken after one hour of vaping, which were compared to a baseline taken one hour before the vaping began in the exposure chamber. Models included Colinss Age, the Dekang 510 Pen, and the Mild M201 Pen, all three e-cigs tested were popular in Poland at the time of the study (though they're terribly outdated today), were purchased online or in mall kiosks, and were charged for twenty-four hours before the experiment.

Five male volunteers who used both e-cigs and traditional cigarettes participated in the second study conducted by the researchers. In this section, the control group emission levels were taken in the chamber, and then the participant was asked to enter and smoke their e-cigarettes for five minutes with thirty minutes in between. After measurements were taken, the room was cleared, and the same participant asked to smoke two traditional cigarettes, with the second being lit thirty minutes after the first. Measurements were once again taken. Cigarettes and e-cigs were not provided by the researchers, but by the participants themselves.

Results of the Research

Key findings of the research indicated that while e-cigarettes release detectable levels of nicotine, they do not release significant levels of carbon monoxide or volatile organic compounds. The level of secondhand nicotine from the vapor depended on the e-cigarette brand. However, the study found that the emissions from nicotine from e-cigarettes were significantly lower than those of standard tobacco cigarettes. Overall, e-cigs have nicotine in their secondhand vapor, but not the combustible toxicants associated with secondhand smoke. Secondhand smoke from cigarettes has nicotine levels ten times higher than that of secondhand vapor released through e-cigs. This study didn't delve into the effects of nicotine, which means that vapers should take consideration when vaping around vulnerable populations.

The findings however, are somewhat supported by that of Dr. Michael Siegal, who noted the results of a California State Health Department air sampling from a vape shop that found virtually no 'secondhand vapor' effect. In this study, a shop lacking ventilation was examined, and while employees and customers vaped at whim, samples were taken. The samples found that formaldehyde levels were consistent with normal indoor and outdoor air levels under baseline conditions, and the only other quantified chemicals were ethanol and isopropyl alcohol. The nicotine levels were almost nonexistent, and this sample was taken from an extreme case, there was no ventilation, and vape clouds lingered as visible. From this information Dr. Siegal, who had previously worked to ban smoking in bars, restaurants, indoor workplaces, and outdoor dining, concluded that there was no significant risk from secondhand vapor.