Exhaled aerosol properties in a room following use of electronic cigarettes and conventional cigarettes
Use of electronic cigarettes (e-cigarettes) is rapidly increasing among smokers as an alternative to conventional tobacco cigarettes (CC). As e-cigarettes do not contain tobacco and do not require combustion, the mechanism of aerosol generation within an e-cigarette and CC is fundamentally different. There is little data available on the properties of exhaled e-cigarette aerosols in the scientific literature and as a result there is a growing discussion amongst the public health community as to whether the “particles” exhaled following use of such products has potential implications for indoor air quality. This study aimed to investigate the aerosol properties within a room during use of e-cigarettes and smoking of CC.
A room-simulating chamber with controllable ventilation rates was used with a bystander simulated using a heated mannequin. Human volunteers vaped an e-cigarette or smoked a CC according to a set puffing regime (i.e. 1 puff every 30 seconds; total 5 puffs). Aerosol particle samples were analysed using a Fast Mobility Particle Sizer (FMPS) spectrometer, Electrical Low Pressure Impactor (ELPI), and Scanning Mobility Particle Sizer (SMPS) at the bystander’s position. The influence of several parameters was tested during this study: product type, room ventilation rate, and the distance between the volunteer and the bystander mannequin.
Our results suggest that particles exhaled following use of e-cigarettes are liquid droplets mainly composed of water. These particles evaporated very fast and disappeared within 10-15 seconds after the puff and were independent of the ventilation rate. By contrast, combustion particles emitted during smoking of CC were much more stable than those exhaled during e-cigarette use (30-45 minutes), and were dependent upon the ventilation rate. This study shows the clear and substantial differences between exhaled e-cigarette liquid droplets and CC smoke particles and should have a positive implication for continued use of e-cigarettes in indoor areas.