Effect of Propylene Glycol on Cigar Mainstream Smoke TNCO Yields

Summary 1,2-Propylene glycol (PG) is one of the most utilized humectants in the tobacco industry. The impact of PG on smoke yields has been extensively studied on cigarettes, but the results are still inconclusive, and, to our best knowledge, nothing has yet been published on the impact of PG on cigar smoke. In this study we investigate the effects of PG on cigar smoke yields, analyzing nicotine, carbon monoxide (CO), water and nicotine-free dry particulate matter (NFDPM or “tar”) content in mainstream smoke from different cigars. We performed a statistical retrospective analysis of four years of internal laboratory data of three cigar brands flavored with blends containing low, medium and high concentrations of PG. Furthermore, to avoid any interference other than PG, experimental cigars with only PG added were produced and analyzed. As for the retrospective analysis, smoke yields seem to be statistically related to tobacco PG content. Cigars with increasing amounts of PG show an increase in water and CO and a decrease in nicotine content. For NFDPM the trend seems quite ambiguous, since it doesn't show the roughly linear correlation with PG contents shared by the other analytes. For these cigars, the effective influence of PG is more difficult to determine due to the presence of complex flavoring blends. In the experimental cigars, the increase in CO, NFDPM and water is clearly related to a higher PG content. PG determines such increase triggering of some still unclarified mechanisms. Among them a variation in combustion conditions perhaps plays an important role. The increase in water content is also related to its higher percent per gram of cigar tobacco, due to the PG effects in both replacing tobacco and attracting and binding moisture. Thermal degradation of PG could also contribute to the increase in CO, while the increase in NFDPM is partly due to pure PG amount delivered from tobacco to smoke. The decrease in nicotine content seems totally related to reduced quantity of tobacco, due to the higher presence of PG.