THE USE OF CIGARETTE EQUIVALENTS TO ASSESS ENVIRONMENTAL TOBACCO-SMOKE EXPOSURE

The development and use of the cigarette equivalent (CE) concept for e stimating exposure to environmental tobacco smoke (ETS) is reviewed. C E is a legitimate conceptual device for reporting and comparing ETS ex posures. However, extension of the CE concept to predicting potential increases in health risk is fraught with numerous assumptions and is, therefore, not as often used or as well accepted. Mathematically, the CE concept relates the magnitude of a nonsmoker's ETS exposure to the magnitude of mainstream smoke inhaled by a smoker. Historically, the C E concept has overestimated nonsmoker exposure in that it has ignored smokers' exposure to their own ETS. The equation defining CE exposure has been modified to include a term for the relative exposure of smoke rs versus nonsmokers which corrects this anomaly. To be meaningful, th e CE equation requires as input both the ETS exposure concentration to which nonsmokers are typically exposed and the mainstream yield for t ypical cigarette brand styles. To date, this type of information has e xisted for only a few ETS tracers (e.g., nicotine and respirable suspe nded particles (RSP)). In an attempt to partially fill this void, main stream smoke yields of several tracers used to assess ETS exposure wer e determined for the 50 leading U.S. cigarette brand styles representi ng 65% of cigarettes marketed in the U.S. during 1991. ETS tracers and other endpoints included tar, nicotine, ultraviolet particulate matte r (UVPM), fluorescent particulate matter (FPM), solanesol, and scopole tin. Sales-weighted, arithmetic mean yields in mainstream smoke on a p er cigarette basis were: tar, 13.8 mg; nicotine, 0.98 mg; UVPM, 10.42 mg; FPM, 7.83 mg; solanesol, 403 mu g; and scopoletin, 14.4 mu g. Thes e results are used in conjunction with ETS concentration data for the same markers obtained in several large ETS exposure-monitoring surveys conducted in the U.S. among nonsmokers. Typical home and workplace CE exposures are both shown to be less than one cigarette per year for a ll tobacco-selective analytes studied. Copyright (C) 1997 Elsevier Sci ence Ltd.