/sci/ - Science & Math

As filter ventilation increases, the cigarette is burned down less rapidly on the smoking machine, and there are more puffs per cigarette (54–59).

As the tobacco rod burns down less rapidly, there is more time for the coal to smolder and form more toxic constituents (54,55,57).

With increased ventilation in the range of most commercial cigarettes, there is decreased air flow through the burning coal tip and lower coal temperatures, resulting in more incomplete combustion and toxic constituents (60–66). An important publication for the chemical yields of two commercial cigarettes that differ by the amount of filter ventilation shows that most toxic constituents are statistically significantly increased (67). The analysis of this study was done with smoke constituent yields on a per-mg-of-nicotine basis, mimicking smoke intake for a smoker adjusting their smoking behavior to compensate for lower nicotine delivery. Among the increased toxicants was (N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), a potent lung carcinogen, in agreement with other published studies (57,64,68–72). Blocking ventilation holes decreases NNK levels (73).

Increasing filter ventilation increases cigarette smoke mutagenicity as measured by the Salmonella Reverse Mutation Assay (Ames test), which is a highly replicated and extensively used assay for the screening of mutagenic potential (74–78) (Supplementary Figure 1, available online) (79). Filter ventilation increases mutagenicity across the full range of cigarette ventilation (69,74,80). An internal tobacco company study assessed six different design parameters to model the contribution of various design changes, including ventilation to mutagenicity, using 30 different research cigarettes (81). Filter ventilation statistically significantly increased the mutagenicity of tar independent of other cigarette designs and tobacco formulations (Figure 6) (81).