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. 2017 May 22;109(12):djx075. doi: 10.1093/jnci/djx075

Figure 4.

Figure 4.

Sales-weighted average tar and nicotine deliveries, 1954 to 1993, and percentage of filter ventilation of cigarettes based on tar yields using the Federal Trade Commission. A) Tar and nicotine as measured by a smoking machine. Source: Hoffmann D, Djordjevic MV, Hoffman I. The changing cigarette. Prev Med. 1997;26(4):427–434. (19). B) Adapted from: Centers for Disease Control and Prevention. Filter ventilation levels in selected U.S. cigarettes, 1997. MMWR Morb Mortal Wkly Rep., 1997;46(44):1043–1047 (22). Bars represent 95% confidential interval. Percentage of filter ventilation is the percentage of a standard puff (two second duration, 35 mL), that is, air taken into puff through the filter vents. A cigarette with no filter ventilation would produce a puff undiluted by air from filter vents; a cigarette with 80% filter ventilation would produce a puff that is 80% air from vents and 20% smoke undiluted by air from vents. Descriptors are no longer allowed by law because they are misleading and because the classification and nicotine yields vary by definition in the literature. ET = expanded tobacco; F = filter; Nic. = nicotine; RT = reconstituted tobacco.