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

Secondhand electronic cigarette (e-cigarette) aerosol (SHA) might impair indoor air quality and expose bystanders. This study aims to investigate exposure SHA in controlled conditions of enclosed settings simulating real-world scenario. An experiment was performed a car room, which generated during 30-minute ad libitum use an e-cigarette. The replicated on five consecutive days each setting. We measured PM2.5, airborne nicotine concentrations, biomarkers SHA, such as metabolites, tobacco-specific nitrosamines, propylene glycol, glycerol bystanders’ saliva samples before, during, after the period. Self-reported health symptoms related were also recorded. results showed that highest median PM2.5 concentration recorded period, being 21 µg/m3 room setting 16 setting—about twofold increase compared baseline. Most concentrations all below limit quantification both settings. Bystanders experienced some short-term irritation symptoms, expressed dry throat, nose, eyes, phlegm. In conclusion, e-cigarette confined spaces increased level caused