Filtration and Retention Characteristics of Smoke Components in Filters

Abstract

SUMMARYThe filtration and retention characteristics of nicotine, phenol, benzo [a]pyrene (B[a]P), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), crotonaldehyde, hydrogen cyanide (HCN) and ammonia in conventional cellulose acetate fiber filters were investigated. By quantitatively analyzing their contents released in mainstream smoke and retained in filters, their filtration efficiencies, taken as the ratio of filter retention content to total yield, were determined under both International Organization for Standardization (ISO) and Health Canadian Intense (HCI) smoking regimes. Using a precision laser cutter, the filters were either cut transversely into 5-7 segments for longitudinal distribution pattern study, or cut transversely into 3 segments firstly and then each segment was cut concentrically into 3 concentric segments for spatial distribution pattern study. Contents of the named smoke components retained in these filter segments were quantitatively analyzed. The data were calibrated and then processed with interpolation analysis and polynomial fitting. The longitudinal distribution patterns for all components mentioned above, as well as spatial distribution patterns for nicotine, phenol, HCN, ammonia and crotonaldehyde, were obtained. The filtration efficiencies of different smoke components varied between 24% and 15% for HCN, 87% and 92% for phenol under ISO and HCI smoking regimes respectively. The filtration efficiencies of all the studied components under HCI smoking were lower than under ISO smoking to different extents except phenol which showed the opposite trend. Different mainstream smoke components have their own retention behavior and distribution characteristics which are determined by the physical and chemical properties of the component and its interaction with cellulose acetate fiber and the glycerol triacetate within the filter. The diversity of retention distribution patterns of different components shows the high complexity of cigarette smoke filtration in filters. [Beitr. Tabakforsch Int. 26 (2014)

Pressure and Gas Flow Distribution Inside the Filter of a Non-Filter Ventilated Lit Cigarette During Puffing

“…The temperature measurements obtained in this work broadly agree with previously published studies (21). When the filter temperature reaches about 60 to 70 °C it will cause softening of the cellulose acetate fibre and possible result in enhanced chemical interactions between the plasticiser and some semi-volatile compounds which otherwise would not occur to the same extent in the earlier puffs (22). Further work is ongoing to investigate the tailing effect of shorter puffs than the 6-s puffs used in this study and to understand the effect of inertial gas flow on filtration behaviour.…”

“…These factors interacted, affecting the filtration and retention of the smoke aerosol and resulted in the observed flow velocity distributions within the volume of the filter. In turn, the interaction of different classes of chemical compounds within both the particulate and vapour phase of the smoke will react differently, as has been experimentally revealed before (4,22,23). The temperature measurements obtained in this work broadly agree with previously published studies (21).…”

“…These highly interlinked chemical mass and heat transfer processes in the filter imply that the filtration mechanisms should be studied in a spatially-related way. In a recent study of this kind (22), localised filtration of a number of volatile, semivolatile and particulate phase smoke components (e.g., ammonia, phenol, nicotine, benzo[a]pyrene, hydrogen cyanide) within a cellulose acetate filter was quantified by analysing cut smoked filter segments -small segments of the used filter were cut using a precision laser cutter to provide averaged concentrations of filtered compounds. The results confirmed that the compounds trapped or filtered by the cellulose acetate filter display different retention patterns in the used filter, suggesting spatially variable filtration mechanisms which may be linked to the flow and accumulation of the smoke condensate on a puffby-puff basis (23).…”

Robustness of HPHC Reduction for THS 2.2 Aerosol Compared with 3R4F Reference Cigarette Smoke Under High Intensity Puffing Conditions

“…Phenol concentration in THS 2.2 aerosol increased simultaneously with puffing regime intensity, which resulted in a diminution of phenol reduction from 92.2 ± 1.4% (HCI) to 63.2 ± 5.8% (extreme regime) for the lowest performance and was reflected by a threshold limit of reduction of 55%. This was possibly caused by the progressive saturation and the subsequent elution of phenol adsorbed on tobacco and other filters (34)(35). PAHs can enter tobacco leaves during curing if the tobacco is exposed to exhaust gases from wood, or other organic fuel, heat sources (36).…”

The Effects of Cigarette Filter Ventilation on Delivery and Retention of Organic Acids

“…The methods for analyzing the retention and distribution patterns of organic acids in the filter were similar to those previously reported (23). A schematic illustration and the parameters of how the filters were cut are shown in Figure 1.…”