105 results about "Cigarette filter" patented technology

A cigarette filter, also known as a filter tip, is a component of a cigarette, along with cigarette paper, capsules and adhesives. It does not make cigarettes less unhealthy. The filter may be made from cellulose acetate fibre, paper or activated charcoal (either as a cavity filter or embedded into the cellulose acetate). Macroporous phenol-formaldehyde resins and asbestos have also been used in cigarette filters. The acetate and paper modify the particulate smoke phase by particle retention (filtration), and finely divided carbon modifies the gaseous phase (adsorption). In laboratory testing, filters have been shown to reduce "tar" and nicotine smoke yields up to 50%, with a greater removal rate for certain classes of compounds (e.g., phenols) compared to others—the filters are particularly inefficient at removing gases of very low molecular weight, such as carbon monoxide. In addition, most of these measured reductions occur only when the cigarette is smoked on a smoking machine; when smoked by a human, the compounds are delivered into the lungs regardless of whether or not a filter is used.