As a measurement of consistent aerosol delivery, simultaneous multi-sensor analysis of physical characteristics of electrically heated tobacco product (eHTP) aerosol reveals the inherent difficulties of utilising commercially available, or specially selected “near commercially available” eHTP systems, as a reference for collaborative or proficiency studies.

Five commercially available systems were explored using a custom aerosol analysis chamber fitted with sensors measuring physical properties such as temperature (in “mouth” and at “lip”), pressure drop and humidity. Data capture was synchronised in a post processing operation. System A and System B used the same consumable sticks and alternate blade heating devices whilst system C, D and E used different heating principle.

System to system variability, as indicated by the COV of a measurement, is illustrated, although each physical measurement shows a different variability hierarchy. For PD COV D>>A>E>B>C; for humidity B>E>D=C>A and for mouth temperature B>C>E=A>D.

Typical variation for the same stick and different device types (A/B) is demonstrated: Heater type A, first puff PD mean of 94.8 mmWg, COV of 0.16, Heater type B PD mean 107 mmWg COV of 0.08. A more consistent aerosol formation was observed with one of the alternate heating systems (Heater type C) where first puff PD was measured at 79 mmWG with COV 0.04. Similarly mouth temperature first puff Heater A, mean 26.4 °C, SD0.86, Heater B mean 25.15° SD1.15.

Consistent aerosol delivery might be improved by strict control of the temperature of aerosol creation with improved uniformity of heating of a standard substrate using an “oven” system. A simple commercial system operating at 182 °C and 215 °C loaded with 0.2 g of cast leaf was investigated. The advantages/disadvantages of this approach and the merits of adopting such an approach for a reference is discussed.