| Measure | Units | Explanation* |
| 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 drop | mm water | Also 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 drop | mm water | Filter pressure drop represents the effort required to draw air through the filter. Indirectly related to smoke removal efficiency |
| Tobacco rod length | mm | Length of tobacco filler |
| Filter length | mm | Length of filter |
| Cigarette diameter | mm | Width 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 length | mm | Distance 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 weight | g | Amount of tobacco matter in the cigarette. Levels of smoke constituents are directly related to the amount of tobacco that is burned |
| Filter weight | g | Mass 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 density | mg/cm3 | Calculated from observed tobacco weight, rod length and diameter. Gives an estimate of average cigarette packing density |
| Filter density | mg/cm3 | Calculated 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