Electronic cigarette (e-cigarette) use has steadily increased since 2010. Indoor e-cigarette use exposes bystanders to a new source of particulate matter (PM) air pollution. Elevated short-term exposures to PM with a lower measuremented aerodynamic diameter (≤2.5 μm), PM2.5 and ultrafine particles (UFPs) have been linked to increased risk of adverse respiratory and cardiac events. This exposure study estimated concentrations of PM2.5 and UFPs from indoor e-cigarette use at 0.5 meters (m) and 1 m away from an e-cigarette user and investigated whether these indoor concentrations varied across three common e-cigarette models. One e-cigarette user tested three different e-cigarettes containing the same nicotine solution on three separate occasions and measured concentrations on PM2.5 and UFPs at 0.5 and 1 m in a ∼38 m3 office. Continuous measures of PM2.5 and UFPs were taken for 5.5 min before e-cigarette use, then the user puffed seven times for 6.5 min (exposure), and for 10 min after ceasing e-cigarette use. Following the initiation of e-cigarette use, levels of PM2.5 increased 160-fold at a distance of 0.5 m, and 103-fold at 1 m. The corresponding increases in UFP counts were 5.2, and 3.0-fold higher, respectively. The PM2.5 concentrations and UFP counts between e-cigarette models were statistically significantly different at 1 m, but not at 0.5 m. There was substantial variability between distances, e-cigarettes, and replicates. This study indicates that e-cigarette vapors influence PM2.5 and UFPs concentrations/counts at close proximity distances indoors; additional research is needed to characterize the composition of those particles and evaluate the impacts of other e-cigarette solutions on indoor air quality. Fine particle pollution concentrations at 0.5 and 1 m away from one e-cigarette user were substantially higher than baseline concentrations and demonstrated distinguishable peaks in concentrations following the exhalation of e-cigarette vapors.

Air pollution, Electronic cigarettes, Indoor, Particulate matter, Smoking
Environmental Pollution
Department of Health Sciences

Volesky, K.D. (Karena D.), Maki, A. (Anthony), Scherf, C. (Christopher), Watson, L. (Louis), Van Ryswyk, K. (Keith), Fraser, B. (Bruce), … Villeneuve, P. (2018). The influence of three e-cigarette models on indoor fine and ultrafine particulate matter concentrations under real-world conditions. Environmental Pollution, 243, 882–889. doi:10.1016/j.envpol.2018.08.069