The impact of different e-cigarette types on indoor fine and ultrafine particulate matter concentrations at close distances

Abstract

Introduction E-cigarettes are increasing in popularity, yet few studies have investigated how they impact indoor concentrations of fine particulate matter (PM2.5; aerodynamic diameter ≤ 2.5 μm), and ultrafine particles (UFPs, aerodynamic diameter ≤ 0.1 μm). Short-term elevations of PM2.5 and UFP concentrations have been shown to adversely impact cardio-respiratory health. To investigate how e-cigarettes’ influence indoor air, our study estimated PM2.5 and UFP concentrations at two close-proximity distances from an e-cigarette user, and evaluated whether these concentrations varied across different types of e-cigarettes. Methods One e-cigarette user tested three types of e-cigarettes with the identical fruit-flavoured nicotine solution on three separate occasions. PM2.5 and UFP concentrations were measured at distances of 0.5 and 1 meter in a 14 m2 office. An adjustable voltage, 1st generation, and pen-style tank e-cigarette were tested. One-second concentrations were measured for 22-minutes divided into: baseline (5.5 minutes), exposure (7 puffs in 6.5 minutes), and post-exposure (10 minutes) periods. The mean concentrations across replicates for each period were calculated. Concentrations between e-cigarettes were compared using analysis of variance. Results At 0.5 meters from an e-cigarette user, the mean PM2.5 concentrations across replicates during the exposure periods were 364 (adjustable voltage), 709 (1st generation), and 1117 (pen-style tank) μg/m3. At 1 meter, the corresponding means were 235, 168, and 1193 μg/m3. The baseline PM2.5 concentrations ranged from 2–3 μg/m3 and the post-exposure concentrations ranged from 2–31 μg/m3. The differences between PM2.5 concentrations among e-cigarettes were statistically significant (P Conclusions At close distances, one e-cigarette notably increased PM2.5 concentrations and UFP counts in the indoor air, but there was high variability between replicates.