We believe that this method provides excellent versatility and throughput for the estimation of mouth-level exposure to a wide range of toxins in cigarette smoke under naturalistic conditions. In addition, this method allows a far more accurate measure of exposure both from a single cigarette as well as from daily smoking.

Background: Benzo[a]pyrene (BaP) is one of the most potent carcinogens generated in cigarette smoke. During smoking, cigarette filters trap a significant portion of mainstream smoke benzo [a]pyrene. This trapped portion is proportional to what exits the end of the filter and is drawn into the mouth of smokers.Methods: We developed a new method to estimate mouth-level BaP intake using filter analysis. In this analysis, cigarettes are smoked by a smoking machine using a variety of conditions to yield a range of mainstream smoke deliveries, which approximate a range of human puffing characteristics. Mainstream smoke BaP collected on Cambridge filter pads and the corresponding 1-cm mouth-end cigarette filter butts is extracted, purified by solid-phase extraction, and quantified by high-performance liquid chromatography coupled with a fluorescence detector. On the basis of the amount of BaP retained in cigarette butts and the amount collected on pads, we can relate them using a linear regression model.Results: Using this model and subsequently analyzing cigarette filters collected from smokers, we are able to estimate their mouth-level intakes, which smokers received when they consumed cigarettes. We made a series of measurements using research cigarettes and select commercial cigarettes having a wide range of machine smoke "tar" and nicotine deliveries.Conclusions: In all cases, results indicate a linear relation of BaP between cigarette filter butts and Cambridge filter pads, with R 2 ranging from 0.93 to 0.98.

Colour can be used to market cigarettes as 'milder', independently of ISO yields and 'Light'/'Mild' descriptors. Banning of 'Light' and 'Mild' brand descriptors may be inadequate to end belief in less harmful cigarettes so long as the tobacco industry remains free to engineer 'mildness' and to use colours, other descriptors and design features to characterise varieties it wants to market as 'milder'.