Introduction
The fundamental principle of tobacco harm reduction is that the health burden of combustible cigarette smoking at both the individual and population levels can be reduced by encouraging smokers to switch to nicotine and tobacco products that support combustible cigarette displacementIt has been proposed that alongside offering sensorial performance and some subjective effects similar to those experienced during combustible cigarette smoking, e-cigarettes that more closely match the nicotine delivery from combustible cigarettes are likely to have greater acceptance and are also likely to be more effective for adult smokers in providing a complete substitute for cigarette smokingThere are several means by which nicotine delivery to e-cigarette users can be increased, such as increasing the e-liquid nicotine concentrationThe addition of various different protonating acids to e-liquid formulations is becoming more prevalent, with lactic, benzoic and levulinic acids recently identified as the three most commonly used among “top sellers”