Influence of nicotine concentration and flavours on mouth level exposure and puffing topography among regular e-cigarette consumers in New Zealand.

E-cigarette aerosols have substantially reduced toxicant profiles relative to cigarette smoke. Consumers' actual exposure is influenced by the way in which they use these products. We have assessed whether consumer puffing topography (e.g., puff duration, volume and frequency), mouth level exposure (MLE) to nicotine and aerosol, or average daily consumption (ADC) are affected by nicotine concentration or flavour. The study was conducted in New Zealand in 2023 among 90 adult e-cigarette users. Puffing topography and MLE were measured for eight e-liquid variants (five nicotine levels, four flavours) in (1) 15-minute vaping sessions during central location testing (CLT); and (2) 7-day home use testing (HUT). The CLT estimated MLE to nicotine increased with increasing concentration of nicotine, while MLE to aerosol decreased, puff duration decreased and interpuff interval increased, indicating that users alter puffing behaviour to achieve a preferred level of nicotine. Results from the HUT supported these findings. In CLT, less acceptable flavours (e.g., Golden Tobacco) led to significantly fewer puffs of shorter duration compared with more acceptable flavours (e.g., Crisp Mint and Tropical Mango). When the participants used their preferred flavour in HUT, there were no differences in MLE per day or ADC among flavours. E-cigarette users maintain a preferred level of nicotine exposure per day by altering the duration and number of puffs taken in response to nicotine concentration. Overall liking of a flavour is likely to be important in providing a satisfactory alternative to continued smoking for smokers who would not otherwise quit.