In this sense, they could be considered as toxic reducers. When comparing

the results for the three additives in Figures 1a and 1b, Al-MCM-41 is by far the best one, showing always positive reductions, and followed by HUSY and NaY. With the latter, the reductions observed are negative in most cases (increase of the yield) but it behaves better than HUSY as the N(F + T) yield increases. The main ability of these mesoporous materials, such as Al-MCM-41, to reduce the yield of most compounds in MSS is demonstrated. By the other hand, the last recommendations on Tobacco Regulations proposed by the WHO (WHO, 2008) were trying to promote laws limiting the content in smoke of some specific toxics, especially the tobacco specific nitrosamines Selleckchem Bcl2 inhibitor (TSNA), which are well-known strong carcinogens. For different reasons these recommendations are still not being applied in the different Regulations on tobacco smoke. In this mean, Lin et al. (2013) TSA HDAC datasheet showed the ability of NaY and specially MCM-41, among other catalysts, to reduce

TSNA in tobacco smoke. As shown in Table 3, ASH is the only single parameter with an increasing trend when the additives are added to the cigarette rod. Figure 2 shows the increase in ASH calculated as the difference between the following ratios; ASH in the smoking experiment with additive to the WTS and ASH when there was no additive to the corresponding WTS and expressed in mass percentage. It can be observed

that the Al-MCM-41 is the one showing the largest increases of such solid residue with almost all brands, followed by the NaY and the HUSY. This increase is due to coke deposited on the material and must be related to the reduction observed in the yields of some compounds, as was proved in a previous paper [19]. Nevertheless, this correlation is not straightforward due to the large number of factors influencing the behaviour of the different systems in the pyrolysis and oxidation reactions. Factors such as the type of paper, its permeability, the number of ventilation holes in the filter, the type of tobacco, the type of material, the temperatures of the processes, etc. are affecting the final results ([1] and [3]). The effect of these additives on the brands studied from is quite different. In order to simplify the analysis, the reductions calculated are shown with more detail only for the best material, Al-MCM-41, and the 10 brands (Table 6). The addition of the catalysts may affect packing of the tobacco into the cigarettes rod, and consequently, to the oxygen permeability, to the temperature profiles during smoking [25] and to the yield of most compounds [22]. As commented above, if the amount of tobacco smoked is less, the yield of any compound is expected to be reduced accordingly.