The widespread use of heat-not-burn products (HNB) is in its infancy and consumer acceptance will involve comparison with existing conventional cigarettes. User perception may be influenced by aerosol delivery temperature and how this is modified by different puffing parameters. The objective of this study was to establish how aerosol temperature varies as a consequence of changing puffing parameters for three commercially available HNB products.

Any change in aerosol temperature was explored using a vaping machine, a Cambridge filter holder modified with a K type thermocouple in the aerosol stream, logging temperature at 4 Hz. Three products, IQOS, glo™ and a Ploomtech, were tested. Experimental protocols were based upon changing the key puff parameters: duration; interval; volume and shape.

As puff count increased, Ploomtech generally increased aerosol temperature whilst IQOS and glo™ reached maximum aerosol temperature after two puffs (24 °C - 27 °C above ambient) with subsequent temperature decline. Increasing puff duration for constant volume/interval had little impact on the aerosol temperature profile of glo™ and IQOS. For Ploomtech and IQOS, changing volume yielded little change in aerosol temperature. For glo™, the lowest puff volume (35 ml) had lower aerosol temperatures. Changing puff interval for consistent puff condition (55 ml puff; 3 s duration) changed the aerosol generated from the glo™ in a not easily understood manner and had minimal impact on the temperature of the IQOS aerosol. The Ploomtech aerosols became hotter as the puff interval decreased (60 s = 1 °C rise, 15 s = 5° rise).

Aerosol temperature for IQOS and glo™ seems independent of the “intensity” of the puffing parameters chosen. Evidence is presented that after the initial two puffs a shorter puff interval yields marginally higher aerosol temperatures. The Ploomtech aerosol temperature increases for more “intense” regimes, shortening puff intervals having the most significant impact.