Table 1 Descriptions of design features and physical parameters assessed in this study
Filter ventilation%Percentage of smoke that is diluted by air when a smoker takes a puff. Filter ventilation is measured at 17.5 ml/s flow rate
Cigarette pressure dropmm waterAlso known as draw resistance. Expression of the effort/pressure required to move air through a whole cigarette at a flow rate of 17.5 ml/s. Contributes to smokers’ acceptance of the product, as smokers find excess or insufficient draw resistance unacceptable
Filter pressure dropmm waterFilter pressure drop represents the effort required to draw air through the filter. Indirectly related to smoke removal efficiency
Tobacco rod lengthmmLength of tobacco filler
Filter lengthmmLength of filter
Cigarette diametermmWidth of the rod. Smaller diameter leads to less tobacco being burned and to increased oxygen availability during combustion, leading to lowered levels of tar, nicotine and other particulates
Tipping paper lengthmmDistance from the end of filter to end of tipping paper. Tipping paper attaches the filter tip to the tobacco rod. The difference between this and filter length determines “overwrap” length
Tobacco weightgAmount of tobacco matter in the cigarette. Levels of smoke constituents are directly related to the amount of tobacco that is burned
Filter weightgMass of the filter. Related to smoke removal insofar as it indirectly measures the number of cellulose acetate fibres on which smoke particles can impact
Rod densitymg/cm3Calculated from observed tobacco weight, rod length and diameter. Gives an estimate of average cigarette packing density
Filter densitymg/cm3Calculated from observed filter weight, length and diameter. Associated with particle removal efficiency (filter efficiency). A denser filter should trap more particles, assuming no differences in the fibre denier or number of fibre cross-connections from the plasticiser
  • *Sources: Browne25 and Norman.26