| 摘要 |
The smoking profile or delivery of particulate matter as a component of smoke in respect of each puff during the smoking of a cigarette is controlled by providing the paper wrapping enclosing the tobacco cylinder with one or more ventilation passages at either the inner or outer surface of the wrapper. The ventilation passages are provided by a strip of combustible material which is secured to the wrapping and has formed therein a number of grooves or channels, the grooves defining with the wrapping the respective ventilation passages. Blocking means are provided in the respective ventilation passages and prevent dilution air from entering the mouth end of the cigarette until a predetermined length of the cigarette has been smoked. The opening of the respective ventilation passages occurs at different times in correspondence to the increasingly higher levels of particulate matter produced as smoking proceeds, the increasing level of ventilation thereby provided controlling the smoking profile to flatten out the curve of particulate matter delivered with each puff. |
