Background: Electronic cigarette (e-cigarette) conventions bring hundreds to thousands of e-cigarette users together socially regularly across the world. E-cigarette secondhand exposures to chemicals in this environment, likely the public setting with the highest concentration of e-cigarette secondhand aerosol, have not been characterized.
Methods: Air sampling for formaldehyde, acetaldehyde, acrolein, nicotine, and propylene glycol was conducted at three e-cigarette conventions and one smaller event from April 2016 to March 2017 in three states in the Southeastern United States. Volunteers attended the events as members of the public and wore backpacks containing air sampling pumps. Control sampling was conducted when venues were crowded for non-e-cigarette events. Additional control sampling was conducted in two venues when they were empty.
Results: Formaldehyde and acetaldehyde concentrations during e-cigarette events were comparable to background concentrations. The median formaldehyde concentrations during events, crowded control events, and empty control events were 12.0, 10.5, and 12.5 μg/m3, respectively. The median acetaldehyde concentrations during events, crowded control events, and empty control events were 9.7, 15.5, and 3.5 μg/m3, respectively. Propylene glycol and nicotine were not detected during control sampling. The median nicotine concentration during events was 1.1 μg/m3. The median propylene glycol concentration during events was 305.5 μg/m3.
Conclusion: Results indicate e-cigarette secondhand exposures are sources of elevated nicotine and propylene glycol exposures. Secondhand exposures to e-cigarettes did not contain consistently elevated concentrations of formaldehyde or acetaldehyde. Additional research is needed to characterize exposures via inhalation to propylene glycol at concentrations measured in this study.
Keywords: Electronic cigarettes; Nicotine; Secondhand exposure; Volatile organic compounds.
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