Abstract
The equality of the two main methods employed to measure ventilation - measuring volume or measuring draw resistance - was demonstrated by various collaborative experiments. In the present paper, on the strength of the draw resistance method formulae were derived to estimate the influence which changes of various parameters have on the degree of ventilation. As cigarette papers with the same permeability can have a very varied effect on the degree of ventilation of the finished product (for this also depends on the draw resistance of the tobacco rod), an attempt was also made to derive formulae which define the contribution every component makes to the degree of ventilation of the finished product. After that, a correlation with the permeability measured was also established. With the help of the formulae, it is also possible to estimate the variations of the results of measurements that occur when ventilation is measured by the volume method with apparatus with high internal resistance. Distribution of the diluting air along the tobacco rod is discussed, both for the unlit and lit cigarette. The increase in the number of draws dependent on ventilation is calculated. The results provide a possibility of explaining the varying reduction of smoke components by ventilation.