Introduction/ Background: Aerosols of electronic nicotine products contain various chemicals such as nicotine, flavoring compounds, propylene glycol, glycerin, volatile organic compounds (VOC) (e.g., formaldehyde, acrolein, benzene), and heavy metals (e.g., lead, cadmium, nickel). Clinical studies have revealed that secondhand vape exposure was associated with respiratory symptoms. Despite demonstrated changes in blood and urine in active vapers and the emerging epidemic of vaping that has increased risk of secondhand vape exposure among non-vapers, passive vaping has received little attention. This analysis aimed to detect blood and urine biomarkers associated with secondhand vape exposure in a nationally representative sample of non-vapers.

Methods: Data from 2017-2020 Pre-Pandemic National Health and Nutrition Examination Survey for participants over 12 years of age were analyzed. Participants were asked if they were in an indoor place where someone was using an e-cigarette or other similar electronic product during the previous 7 days. Samples for blood biomarkers and urine metabolites were obtained in Mobile Examination Centers. Differences between exposed and nonexposed participants were estimated using two-tailed t-test.

Results: Of 4,318 participants who responded to exposure question and provided laboratory samples, 495 (13.95%) reported exposure to secondhand vape in previous 7 days. Compared to nonexposed participants, exposed participants had a significantly higher mean for blood levels of phenyl mercapturic acid (p<0.0001), 2,5-dimethylfuran (p<0.0001), benzene (p<0.0001), benzonitrile (p<0.0001), furan (p<0.0001), selenium (p=0.0004), and cadmium (p<0.0001) as well as urine levels of manganese (p=0.0002). Some variations were observed by sex, race, and ethnicity.

Conclusions: Future research can examine socio-behavioral and attitudinal factors associated with secondhand vape exposure in various environments, long-term health outcomes, and how specific chemicals detected in blood and urine vary depending on aerosol concentration in the environment, duration of exposure, and individual susceptibility. Regulations, guidelines, and interventions are potentially needed to prevent harmful effects of secondhand vape exposure.