Assessment of indoor air quality at an electronic cigarette (Vaping) convention.

E-cigarette (vaping) conventions are public events promoting electronic cigarettes, in which indoor use of e-cigarettes is allowed. The large concentration of people using e-cigarettes and poor air ventilation can result in indoor air pollution. In order to estimate this worst-case exposure to e-cigarettes, we evaluated indoor air quality in a vaping convention in Maryland (MD), USA. Real-time concentrations of particulate matter (PM) and real-time total volatile organic compounds (TVOCs), CO and NO concentrations were measured. Integrated samples of air nicotine and PM concentrations were also collected. The number of attendees was estimated to range from 75 to 600 at any single observation time. The estimated 24-h time-weighted average (TWA) PM was 1800 μg/m, 12-fold higher than the EPA 24-h regulation (150 μg/m). Median (range) indoor TVOCs concentration was 0.13 (0.04-0.3) ppm. PM and TVOC concentrations were highly correlated with CO concentrations, indicating the high number of people using e-cigarettes and poor indoor air quality. Air nicotine concentration was 125 μg/m, equivalent to concentrations measured in bars and nightclubs. E-cigarette aerosol in a vaping convention that congregates many e-cigarette users is a major source of PM, air nicotine and VOCs, impairing indoor air quality. These findings also raise occupational concerns for e-cigarette vendors and other venue staff workers.