One of the potential concerns of secondhand vapor consumption is that the intake of smoke can deposit small particulate matter in the lungs. These particles could then induce inflammation or cell damage. However, a recent study by Qingyu Meng and colleagues at the Rutgers School of Public Health suggests that most or even all small particles from vapor are not harmful.
The research conducted shows that low power e-cigarettes do not deposit many particles, nor do these particles seem to affect lung function. High power devices, like sub ohm vapes, have a higher chance of depositing particles in the respiratory tract, but these particles still were easily flushed out by regular immune function and homeostatic properties of the human body. The overall conclusion from this research supported the idea that while particles do get deposited in the respiratory tract, these extremely small bits of matter don’t tend to be harmful.
Another study on secondhand smoke from vaping devices recently came from researchers at the Department of Public Health and Infectious Diseases at the Sapienza University of Rome. Here, the scientists wanted to find out whether ultra-fine particles - particles smaller than 0.1 micrometers in diameter - were deposited in the respiratory tract of those passing by someone vaping. The researchers also wanted to determine if there was a different concentration of particles in respiratory tracts of people at different ages, including infants and senior citizens.
These researchers confirmed that there is particle deposit from e-cigarettes and other vaping devices, but the concentration of these particles is 10 times less abundant than those deposited from traditional cigarettes. The study also showed that there are fewer particles produced from a normal e-cigarette than from other vaping devices. Overall, this study showed that e-cigarettes are far healthier for both direct vapers and for those who accidentally intake the smoke secondhand.
A third study came out last year that examined the inhalation of potential toxicants from e-liquids. This work, done by researchers at Lawrence Berkeley National Laboratory, modeled inhalation rates of nine different compounds and potential effects on health. The three most common of these toxicants are acrolein, acetaldehyde, and formaldehyde. These are all commonly found in the propylene glycol or vegetable glycerin mixture, though in low enough doses to be totally harmless.
The researchers showed that higher voltage devices produced more aerosolized emissions of these three toxicants, though the per-puff emission rate of each was barely above 100 micrograms. The research also showed that though the toxicants are retained on a day-to-day basis during secondhand intake, the concentrations are far too low to cause any significant harm. Though the doses are extremely low, this study showed a solid foundation for what ingredients of e-liquids should potentially be replaced with less harmful ones.
Scientific studies are necessary to fully understand the effects of vaping on both primary users and those who intake secondhand smoke. While there is still uncertainty by the public on how harmful secondhand smoke is, the research so far indicates that there is no significant effect of vapor on general health. Long-term studies are still looking at health effects over time, but there is no need to worry - current scientific consensus suggests the long-term effects will be minuscule or nonexistent compared to traditional cigarette smoke.