In order to promote smoking bans to protect nonsmokers from the hazards of secondhand smoke exposure, a number of anti-smoking groups are appropriately providing estimates of the cigarette equivalent exposure of nonsmokers. This is an estimation of the amount of a particular tobacco smoke constituent that a nonsmoker would inhale in a given environment in comparison to the amount of that same constituent which would be smoked by an active smoker of a given amount of cigarettes per day.
Such a comparison is very useful and important because it gives policy makers and the public a sense of the actual amount of tobacco smoke constituents that a nonsmoker may inhale. This may be more meaningful to a lay person than simply providing data on the level of a constituent in the ambient air.
For example, if I say that the level of NDMA in a restaurant is 0.05 ng/L, it might not mean anything to a policy maker. But if I say that the amount of NDMA that a nonsmoker working in such a restaurant would inhale over an 8-hour shift is the same amount inhaled by an active smoker of 1 pack of cigarettes per day [this is just a hypothetical example], that provides a lot more meaningful data for the policy maker.
So the desire and attempt to present cigarette equivalents is a natural one and a reasonable one.
A number of anti-smoking groups are presently disseminating estimates of cigarette equivalents on their web sites:
Smoke-Free Illinois: "One eight hour shift in a smoky workplace is the equivalent of smoking 16 cigarettes."
Pennsylvania Alliance to Control Tobacco: "During an 8-hour shift, bartenders “smoke” the equivalent of a pack of cigarettes without ever lighting up."
SmokeFreeOhio: "Working in a smoker-friendly office 8 hours" is equivalent to actively smoking 6 cigarettes.
Smoke Free Cleveland: "Working in a smoker-friendly office 8 hours" is equivalent to actively smoking 6 cigarettes.
Smoke Free Cleveland: "Research from the University of California at Berkeley shows that sitting in the non-smoking section of a restaurant for two hours is the equivalent of smoking one and one half cigarettes. Working an 8-hour shift at a bar, a nonsmoker would inhale the equivalent of 16 cigarettes."
Smoke Free Galveston: "Sitting in the non-smoking section of a restaurant for over an hour can be as harmful as smoking 1-1/2 cigarettes. Two hours in a smoky bar is the same as smoking nearly four cigarettes."
Kentucky Center for Smoke-Free Policy: "Working a shift in a smoky bar is equivalent to smoking a pack of cigarettes per day. If you are in a smoky bar for two hours, it is the same as smoking four cigarettes."
Smoke Free Arizona: "Working a shift in a smoky restaurant or bar is equivalent to actively smoking nearly a pack of cigarettes."
Smokefree Mecklenburg: "If you worked in a smoker-friendly office for eight hours, you would smoke six cigarettes without even lighting up."
Smokefree Naperville: "One eight-hour shift in a smoky workplace is the equivalent of smoking 16 cigarettes."
The Rest of the Story
The problem with cigarette equivalent statements is that the number of cigarette equivalents varies widely, depending on the specific smoke constituent that one is talking about. So if you don't provide the tobacco smoke constituent, then your statement is going to be very misleading.
Note that the deceptive nature of cigarette equivalent claims can work both ways.
If you claim, as the anti-smoking groups do above, that an 8-hour shift in a smoky bar is the equivalent of actively smoking 16 cigarettes, you are presumably referring to the nonsmoker's dose of NDMA (N-nitroso-dimethylamine) or some similar constituent which is much more highly concentrated in sidestream smoke than in mainstream smoke.
The problem is that under the same conditions, the number of cigarette equivalents of some other tobacco smoke constituents is much smaller. The most pronounced is nicotine itself, for which the cigarette equivalents under the above conditions is only about 0.8 cigarettes.
So it would be technically correct for a smoking ban opponent to claim that in terms of nicotine, the exposure of a nonsmoker working in a smoky bar for 8 hours is equivalent to less than a single cigarette.
It would be equally correct for a smoking ban proponent to claim that in terms of inhaled NDMA, working in a smoky bar for 8 hours is the equivalent exposure as an active smoker of about 16 cigarettes.
Both of these statements are correct, and accurate.
However, you can easily see that by leaving out the smoke constituent you are talking about, you can easily create a misleading statement.
For example, a smoking ban opponent could state that working in a smoky bar for 8 hours is no worse than actively smoking less than a single cigarette.
A smoking ban proponent could state that working in a smoky bar for 8 hours is the same as actively smoking 16 cigarettes.
Both of these statements are wrong. They are certainly very misleading. And by leaving out the smoke constituent in question, it seems to me that the intent of someone make such an unqualified claim is to deceive.
The smoking ban proponents who are claiming that the nonsmoker exposed for 8 hours will suffer the same health effects as if they smoked 16 cigarettes a day are wrong, and they are being deceptive, probably intentionally.
The smoking ban opponents who are claiming that the nonsmoker exposed to 8 hours will suffer the same health effects as if they smoked less than a cigarette are also wrong, and they are also being deceptive, probably intentionally.
So you see, the only way to be accurate and not to be deceptive is to simply make it clear for what smoke constituent you are estimating exposure.
In this case, including the "caveat" marks the difference between a correct and an incorrect statement. While Dr. Glantz has argued that we cannot include the caveats because the public cannot understand them, I strongly disagree. I think the caveats are what mark the difference between accuracy and inaccuracy, correctness and incorrectness, objective science and subjective manipulation, honesty and deception, truth and falsehood.
In fact, it is the "caveats" that mark honesty and objectivity against deception and politically-motivated bias.
I have already made my own opinion clear: the fact that nonsmokers in a smoky bar are inhaling the equivalent amount of even one carcinogen as an active smoker of about 1 pack per day is alarming, and argues for the protection of those workers from exposure to that carcinogen. The fact that other cigarette equivalents may be less does not obviate the need to protect the nonsmoker from the highest harmful constituent exposure.
However, while that fact may argue for the need for smoking bans, it does not justify the inaccurate communication of this information to policy makers and the public, as the above anti-smoking groups are doing.
Why the need to be deceptive? The truth should be enough. If nonsmokers are inhaling the equivalent amount of NDMA - a single carcinogen - as active smokers of nearly a pack per day, then how can one justify failing to protect them from this exposure?
There's no need for deception here. Just tell the truth.
(Thanks to Bill Hannegan for the tip and for the links.)