Tar, nicotine and carbon monoxide (TNCO) cigarette yields determined under different smoking regimes form part of a continuous linear function, with filter ventilation both blocked and open, when linked to the reduction ∆t in the smoking time due to puffing (ST09 - CORESTA 2013). This means that the use of a single smoking regime is sufficient to characterise emissions for a particular product if the smoulder rate is known. However, this single smoking regime has to be carefully chosen because the application of intense conditions can produce high water yields leading to trapping issues, to high analytical variability and to over estimation of tar yields. In addition, the smoulder rate determination involved in the calculation of ∆t can be difficult for cigarettes with low ignition propensity design which present some tendency for self-extinguishment during measurement.

Experimental issues were overcome in a novel testing scheme involving the determination of smoking times under two smoking regimes and inputting this data into a burning model. Beyond inter-puff smoulder rate determination, the model was used to provide an extensive set of information such as the weight of tobacco burnt during puffs. Good correlations were observed between the mass of tobacco burnt during puffs and TNCO or benzo[a]pyrene yields derived under ISO validated methods.

It was concluded that the application of two smoking regimes is required to provide smoking times and ∆t but the analysis of the yields is required from only one of them; taken together, this is an optimal scheme since it provides comprehensive characterisation of products at reduced cost. An appropriate choice of validated smoking regime for yield determination (e.g. ISO regime) could then overcome the limitations observed with the Health Canada intense regime and still fit with the regulatory purposes of product monitoring and characterisation.