Electronic cigarette use and indoor air quality in a natural setting

<h3>Introduction</h3> Secondhand smoke (SHS) from combustible cigarettes causes numerous diseases. Policies have been developed to prevent SHS exposure from indoor cigarette use to reduce health risks to non-smokers. However, fewer policies have been implemented to deter electronic cigarette (ECIG) use indoors, and limited research has examined the impact of secondhand exposure to ECIG aerosol. <h3>Methods</h3> Indoor air quality was measured at a 2-day ECIG event held in a large room at a hotel. Fine particulate matter (PM) was measured using 2 devices that measured concentrations of PM 2.5 μm aerodynamic diameter or smaller (PM_2.5). Measurements were taken before the event, over 2 days when the event was ongoing, and the day after the event. PM_2.5 measurements were also taken from the restaurant at the hotel hosting the event and a restaurant at a nearby hotel. <h3>Results</h3> During 6 time points when the event was ongoing, between 59 and 86 active ECIG users were present in the event room (room volume=4023 m³). While the event was ongoing, median PM_2.5 concentrations in the event room increased from a baseline of 1.92–3.20 μg/m³ to concentrations that ranged from 311.68 μg/m³ (IQR 253.44–411.84 μg/m³) to 818.88 μg/m³ (IQR 760.64–975.04 μg/m³). <h3>Conclusions</h3> PM_2.5 concentrations observed at the ECIG event were higher than concentrations reported previously in hookah cafés and bars that allow cigarette smoking. This study indicates that indoor ECIG use exposes non-users to secondhand ECIG aerosol. Regulatory bodies should consider establishing policies that prohibit ECIG use anywhere combustible cigarette use is prohibited.