Environmental and individual exposure to secondhand aerosol of electronic cigarettes in confined spaces: Results from the TackSHS Project.

Introduction:
This text provides a summary of a study on the exposure to secondhand aerosol (SHA) of electronic cigarettes (e-cigarettes) in confined spaces. The study aimed to comprehensively investigate bystanders' short-term exposure to SHA in controlled conditions that emulate real-life scenarios by carrying out a combination of environmental and biological assessments in confined settings.

Key Points:

* The study was an experimental study in two confined settings, a room and a car, where two bystanders were exposed to aerosol produced from short-term e-cigarette use.
* The study was performed with volunteers in the course of one week in each setting and was conducted in July and August 2019.
* The participants were recruited through a database of previous studies and personal contacts of the research team.
* Environmental measurements included gas-phase nicotine and real-time airborne mass of PM 2.5 concentration.
* Biological measurements included saliva samples collected from the two non-users four times in each daily replicate in both settings.
* Observational measurements included puff frequency and self-reported health symptoms.
* The study found that short-term e-cigarette use in confined spaces increased indoor PM 2.5 level and caused some irritation symptoms in bystanders.

Main Message:
The main message of the study is that e-cigarette use should be considered in indoor clean air policy given its ability to impair the indoor air quality and negatively affect bystanders. The study demonstrates that short-term e-cigarette use in confined spaces, a room and a car, more than doubled the PM 2.5 concentration and, in a room, the concentration remained higher than the baseline level after the e-cigarette use was stopped. Additionally, although very low levels of airborne nicotine and biomarkers of passive exposure to e-cigarette aerosol were detected, bystanders reported some mild irritation symptoms, such as dry throat, eyes, and nose, after the exposure to e-cigarette aerosol. Therefore, policy makers should consider these findings when developing regulations for e-cigarette use in indoor spaces.

Amalia B, Fu M, Tigova O, et al. Environmental and individual exposure to secondhand aerosol of electronic cigarettes in confined spaces: Results from the TackSHS Project. Indoor air. 2021;31(5):1601-1613. doi:10.1111/ina.12841