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Filter TechnologyTargets Irritating CompoundsIrritating cigarette smoke has been the bane of smokers as well as tobacco scientists for decades (1). Even with the some of the best scientific tools at their disposal, scientists in the tobacco industry as well as those in universities have struggled to understand why some cigarettes give an irritating smoke while apparently very similar cigarettes give a smooth smoke (2). As with most agricultural products, there are season-to-season and farm-to-farm differences in the same type and grade of tobacco. Tobaccos that give a good smoke one year, may give a harsh and irritating smoke the next year (3). Many smokers have noticed that their favorite brand will suddenly turn harsh and irritating without explanation and then return to normal when they buy the next carton. Perhaps they got a carton of stale cigarettes (4). All the smoker knows is that he has spent his hard-earned money and gotten a bad tasting, irritating smoke. Over the years, scientists in the tobacco industry have developed processes, additives, and filters to make a smoother smoke. For example, in some countries such as Japan, many cigarette brands have filters that contain activated charcoal. Such cigarettes have little irritation, but also have so little smoke taste that they are too bland for most American smokers (5). Until the advent of the patented Wellstone filter, it was difficult to find a cigarette that had consistently good taste without the irritation. On the outside, the patented Wellstone filter looks like the common cellulose acetate filter found on most filter cigarettes; but on the inside, there is a special additive that is derived from common vegetables. This special additive is believed to reduce the irritating compounds in smoke. Based on the available evidence, the patented Wellstone filter keeps the smoke smooth. Furthermore, it has been found that this patented Wellstone filter reduces the mutagenicity of the smoke as measured by the Ames assay. In studies of the relationships among several in vitro assays and rodent carcinogenicity, the Ames assay gave the best concordance (6,7). While it is not known if Ames assays on cigarette smoke are relevant to smoking-related diseases, toxicologists in the tobacco industry view lowered Ames activity as an indication of reduced biological activity (8,9).
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