Emerging regulation of e-cigarettes may require that cell cultures and the like are exposed to whole e-cigarette aerosols. Part of the mechanics of this process involves first the generation of the aerosol and then the transport to the exposure system, the desire being that the aerosol used on the cell culture to be substantially similar to that generated at the mouth end of the e-cigarette.

An ideal puffing system was constructed and its performance explored using a number of different “cig-a-like” products A to G.

Firstly the mass lost in the system was examined and then the change in aerosol droplet size distribution through the puffing process. Brand to brand differences were observed as were differences associated with the experimental set up and puffing parameters.

Mass losses through the equipment were surprisingly low, between 3% and 7% by weight of the total being retained in the system. A “priming” process was observed where losses diminished with puffing.

Aerosol droplet size distribution varies on the basis of brand and puffing conditions at the mouth end of the e-cigarette and this has an observed impact on droplet size distribution at the exhaust of the system. When the median droplet diameter exceeded a defined size there was a noticeable loss of larger droplets through the system. Where the median distribution was below this limit the distribution of droplets at the exhaust was largely maintained unless the exhaust path was lengthened where upon an increase in larger droplets was observed presumably due to inelastic droplet/droplet collisions within the exhaust path.

The significance of these findings is discussed in the context of equipment design for use in non-clinical studies.