Analysis of Secondhand E-cigarette Aerosol Compounds in an Indoor Setting

Objectives: In this study, we measured concentrations of PM2.5 and major volatile organic compounds (VOCs) present during a real-world indoor e-cigarette event. Methods: Particulates of 2.5 mu m aerodynamic diameter or smaller (PM2.5) were measured using personal aerosol monitors, and air samples were collected using thermal desorption tubes, before and during the e-cigarette event. Results: The average median concentration of PM2.5 measured pre-event was 3.0 mu g/m(3) and during the event was 81.4 mu g/m(3). Event levels of PM2.5 ranged from 40.0-447.0 mu g/m(3). The total pre-event VOC concentration was 220 mu g/m(3) compared to 330 mu g/m(3) during the event. Compounds with the largest increase in concentration from pre-event to event samples were propylene glycol (PG) (3 mu g/m(3) to 110 mu g/m(3)) and vegetable glycerin (VG) (0 mu g/m(3) to 35 mu g/m(3)). Conclusions: PM2.5 concentrations during the event were comparable to those previously reported in bars where cigarette smoking was allowed. PG and VG concentrations were substantially higher in the event samples compared to pre-event samples. Given emerging knowledge on the health impacts of inhaling these compounds, regulators should consider policies that prevent exposure to secondhand e-cigarette aerosol in workspaces and public places.