Sorry vapers, it’s not “just water”. A study in Nature found quite dreadful air quality at a vaping convention where indoor use of e-cigarettes was allowed.
The estimated 24-h time-weighted average (TWA) PM10 was 1800 μg/m3, 12-fold higher than the EPA 24-h regulation (150 μg/m3). Median (range) indoor TVOCs concentration was 0.13 (0.04–0.3) ppm. PM10 and TVOC concentrations were highly correlated with CO2 concentrations, indicating the high number of people using e-cigarettes and poor indoor air quality. Air nicotine concentration was 125 μg/m3, equivalent to concentrations measured in bars and nightclubs.