Tobacco Documents Online

C Sidestream Smoke-Fact and Fiction ABSTRACT *` Proponents of :rion-smoker's rights to clean air have been anxious to reinforce their position with ''scientific evidence of heal!tK risks associated with passive exposure to tobacco`smoke."' Strong emotional pressures have influenced the design an6interpretation of research efforts in this area. However, the combined, evidence so far obtained does not support the contention that passive smoking under prevalent conditions is conducive to objectively measurable health risks. INTRODUCTION ` It ts important to recognize at the outset that today it is vimtual!ly impcssible to discuss the smoking and health issue in strictly objective and scientific terms. There is no denying that the subject is laden with moralistic overtones to the point where it is not always easy to separate fact from emotion. Personalily, I am prone to make strong statements to the effect that nobody should smoke and would certainly adivocate a smoke-free soc iety. But can one ignore the 60 million Americans who continue to smoke and the perhaps one billion people throu5hout the world who engage in this habit-- over 20% of the entire worlid population? L?7rt ~ For these people, an admonition has very little meaning; some of them actually may think of it as patronizing, but this does not deter me or many of my colleagues from trying to win,thef,smokers to our side by whatever arguments we might have. {The issue'of passive sm©king! - or better, invol'untary smoking!, - has been one of the strongest`arguments used and, in effect, it says to the smoker: "Your right to smoke denies me the right to be smoke free and in so doing it endangers my health." This argument has been used successfully to provide segregate& facilliities for smokers and nonsmokers in a variety of social gatherings. From a legdl and moral point of view, it has ha& a compelTing appeal, and it is likely to be used again and again to further advance the nonsmoking point:of view. • . ..: ~... : , . . . _. `' -At various times, many attempts have been made to buttress the legal and moral skeleton of this argument with supportive statements from the most popular and successfully persuasive force today, namely, science. But to a dispassionate observer it is apparent that, as one may predict, the grafting of scientific pursuits on to a vigorous advacacy, has resulted' in effective public relations, and even legislative action, but at the cost of leaving science abuse&in too many instances. This paper wilil attempt to take the point of view of science and! objectively appraise factual evidence related to passive smoking, and health. I am fully aware that such a statement on my part entail's substantial arrogance and the presumption that my analysis wili1 be indeed objective and respectful of scientific impartiality. Absolute faithfulness to this principl'e is obviously impossible, but I' wilil try, and the question-and'-answer period at the end may further expose my bias and balance it with that of other colleagues in the audience. 03'735113 Gio B. Gori, Vice President, Franklin Institute, Silver Spring, Maryland THIS PREPRINT FOR DISCUSSION PURPOSES ONLY. FOR INCLUSION 7N ASHRAE TRANSACTIONS 198A, V.90,R1. L Not to be reprinted in whole or in part without written permission of the American Society of Heating, Reffigerating and Air• Condi- tioning Engineers; Inc.. 1791 Tullie Circle NE. Atlanta. GA 30329. Opinions, findings, conclusions, or recommendations ex- pressed in this paper are those of the author(s) and'do not necessarily rellect the views of ASHRAE. i

L b. .~ , DISCUSSION There are many excellent reviews on this topic, and a goo&piace to start is with the assessment made in the Surgeon General"s Report (1979) and to account for the most salient publications thereafter. In considering the issue of passive smoking and'health, it is important to firmly keep in mind two, fundamental conditions. First, passive smoking is not a one time, one dose insult, but occurs naturally from virtually zero to very high concentrations, and the frequency or probabiTity of nonsmoker exposure is greater in natural! situations where the concentration of ambient smoke is low. Secondly, the exposed population of nonsmokers is not homogeneous and ranges from a majority of healthy individuals fully capable of withstanding, passive smoking, to smaller and' smaller groups of people as their susceptibility to passive smoking increases, due to innate systemic deficiencies or to concurrent diseases. The combination of these two conditions obviously creates a variety, of possible statements about their interactions, ranging from no effect whatsoever, when~ one matches low levels of exposure with nonsmokers in very robust health, to significant concern when matching high levels of exposure with highly susceptible, sick, or otherwise impaired nonsmokers. And, while the former situation would not reqNire any protective action,, the latter would obviously carry a strong message of needed protection, even thoughiit would be encountered in rare instances, easily identified and remedied. Bothi situations are abnormal, and the reali issue therefore centers on what might be the interactions between passive smoking and nonsmokers in the most prevalent natural conditions, namely, those conditions that are likely to effect large segments of the population and thus require massive intervention. The 1979 Surgeon General's Report recommende& that research priorities should be focused on children and' patients with coronary heart and chronic lung diseases. It recommended that prospective studies should analyze the reall prevalence of respiratory allness in children exposed to passive smoking and warned that care should be exercised to control a number of confounding factors that may bias the results. In effect, the report `.'recognized that the available evidence coul&not be taken at face value. Specifically, the :report indicated that parental neglect connected with socioeconomic status may play a role, or that children of smokers may have a greater opportunity to come in contact with illness because smokers as a group are more sociable. On a different subject, the report addressed the possibility of impairment of psychomotor performance, especially for the combinat'i~on of high carbon monoxide levels and ~alcohol intake. However, objective evidence indicated such impairment could only be expected at levels of CO exposure far above what is usually experienced by passive inhalers. In fact, a review conducted under the author's direction (Gori, 1978) at that time by a panel of distinguished'scientists at the National Institutes of Health addressed .the question of whether it may be prudent to ask pilots of commercial airlines to refrain from smoking while on duty. The panel unanimously concluded that, for pilots who are habitual smokers, the prohibition of smoking on the job may result in a greater danger to aircraft and passengers than if the pilots continued to smoke in their customary way. connected passive smoke exposure under laboratory conditions with aggravated symptoms of angina pectoris. In his studies, the levels of nicotine intake were extremely small, and the Surgeon General's Report itself warned that the results could welil be attributed to the stress imposed by the experiment rather than to the actual exposure to passive smoking. The 1979 Surgeon General's Report also focused on the studies by Aronow (1978), who Overall, the 1979 Surgeon General"s Report could only deal with circumstantial evidence about possible effects for small population segments that might be considered highly susceptible and at risk, that is, children and angina pectoris patients. The situation at that time was summarized by an authoritative editorial that appeared in the British Medical Journal ("Breathing Other People's Smoke" 1978), carrying the statement ' or the moment most - but not all - of the pressure for people (including many smokers),to breathe smoke free air must be based on aesthetic considerations rather than oni known serious risks." Levels of Passive Smoke 03735114 Since the 1979 Surgeon General's Report, various studies have appeared that can be divided into two main categories. Ohe type deals with levels of exposure to passive smoke, thQ other with observations om the potential health effects of passive smoke inhalation.

- Particulate levels in ambient air measured by various researchers range from a mean or 21 to a peak of 1,150 nanograms per cubic meter, the first in a hospital and' the latter inn pub. Other results clearly indicated that air pol!lutiun l!evels cani give large values of particulate matter, regardless of smoke contaminatiom. -.~. . ' ~. rs.. .. . 1leber'and Fischer (1980)1, and Repace and Lowrey ('198®) measured various levels of indoor pollution using a piezoelectric balance and'attributed various estimates of exposure to passive smoking. Their results were questioned for two main reasons. First, what was measured was total particulate matter and not necessarily, that exclusively derived from tobacco smoke. Second, the reliability and reproducibil,ity of results obtained with the instruments used are probably not sufficient to give confidence that the results would be consistently true. Third, certaiin standardizations used, particularly by Repace and Lowrey, have beenichallenged. Standardizing, as they did, to a cigarette that yields .5 mg of tar led to estimating very high tar exposures for passive smokers. It was noted that, in reality, the average cigarette yields over 15 mg! of tar, which would' have resulte6 in reducing thei'r.estimates by almost 30 times. • 3 In regard to"nicotine, Badre and his associates (1978) were able to measure levels up to 215 micrograms of nicotine per cubic meter in, an atmosphere heavily contaminated with smoke. `.:They were able to, point out that previous experiments attempting to measure nicotine in limited spaces had been biased because nicotine tended to revolatilize from, filter pads on which tar particl'es were trapped as a consequence of high gas flow through the filter, itself. However, even the significant level's recorded by Badre translate in terms of_average passive intake equivalent to less than 4% of one cigarette per hour. ; fCarbon: monoxide has been one of the most frequently used' indicators of smoke concentration..It should be noted, though, that CO is not specific to cigarette smoke unless studies are controlled very precisely for foreigni CO sources. Moreover, several studies have used an instrument known as the "Ecolyzer," which, while quite precise and reliable, can give erroneous readings whenithe measured air contains alcohol. Many of the studies have looked for high levells of smoke contamination in nightclubs and bars where the bias introduced by ethanol could obviously be more significant. 1~. Measuring! the differences of CO concentration between smoking and nonsmoking areas, Fischer (197k)i found an average of .7 ppm difference between smoking and nonsmoking areas in cafeterias. Differences between indoor and outdoor areas varied from no difference in the studies by Chappell and Parker (11,977) to levels of 9.5 ppm as measure& by Cuddelback and associates (1976). In general, the studies reported indicate that it is highly unlikely that passive smokers would exceed the 3% level of COHb in the blood, a level not associated with appreciable impairment. Other tobacco components or smoke components have been measured,''such as acroleine, polycyclic hydrocarbons, and nitrosamines, but their -levels have either not been~ reliably measured, or they were insignificant with regard to potential, risk. =;In general', passive smokers in most common circumstances are 1'ikely to be exposed to doses that are orders of magnitude smaliler than for inhaling smokers. Potential Health Effects Another group of studies since the 1979 Surgeon General's Report has focused on potential health effects associated with passive smoking. Two of these studies have made international headlines and have been the subjects of intensive scruti'my: the studies of Hirayama (1981) and of Trichopoulos and associates (1981). Both claimed that nonsmoking wives of smokers have a significant and greater ri'sk of 1'ung cancer than nonsmoking wives of nonsmokers. The second study mentioned involved only 40 lung cancer cases in nonsmoking women. The authors are careful' to point out that the sample is too small to allow significant conclusions, an& the study wouldlhave probably enjoyed'only passing attention, were it not that the Hirayama study was publii'shed at the same time. 03735115 The Japanese study was based on a much larger sample, but apparently it was plagued1by a host of methodological an& interpretive problems that have been extensively scrutinize6 in the public and scientific press and still occasionally resurface today (Lee, 1982; Lehnert, 1981). Without getting into the detail of the criticism, it is fair to say that the Hirayama study is difficult to accept, especially, because it implies a high risk in, nonsmokers, comparable to that of regular smokers, when indeed their exposure must be orders of magnitude smaller. The inconsistency of that study was emphasized by the subsequent publication of a study by the American Cancer Society (ACS) authored by Garfinkel (1981). i

This study was based'on the ACS"s very large prospective study and the United States veterans study, both combining almost three mililion people. The analysis could not find evidence of any trend in lung cancer for nonsmokers in both studies, and it showed that nonsmoking women married to smokers of over 20 cigarettes a day had lung, cancer rates virtually indistinguishable from wives of nonsmokers. A1'l this suggests that, because passive smokers receive low, doses, passive smoking has a negligible role in lung, cancer incidence. The conclusion is not that passive smoking is safe, but rather that its effects, if any, are too small to be detected and, hence, probably unimport'~ant. As far as pulmonary function is concerned, a paper by White and Froeb (1980) received considerable attention in the scientific and lay press. The study found some significant differences in forced mid'' expiratory flow and in forced end-expiratory flow in nonsmokers exposed tolpassive smoking,. The study was criticized on grounds that its instrumentation and methodologies were unreliable and out-dated and that the procedures used to, select the sample of 3000 men and women were not appropriate. Doubts about the validity of this paper further increased after the publication of a paper by Comstock and associates (1981), who came to the conclusion that "the presence of a smoker in the house other than the subject was not associated with the frequency of respiratory symptoms and only suggestively associated with evidence of impaired ventilatory function. The use of gas for cooking was related to an increased'frequency of respiratory symptoms and'impaired ventilatory functions among men, being most marked among men who had never smoked. There was no evidence that cooking with gas was harmfuli to women." A paper by Shepherd et al. (1979) reported a study by 14 volunteers and'~came to the conclusion that "data do not suggest that asthmatic subjects have an unusual sensitivity to (passive) cigarette smoke." Another paper by Dahms et al. (1981) reports impairment in asthmatics exposed to high levels of passive smoke in an environmental chamber, but it could, not be excluded that the effects were due to psychological factors, since the experiment lacked adeqNat'e controls. t In general, though, the issue of lung cancer risk in passive smokers has received most of the attention. The 1982 Surgeon General's Report summarized the overall situation as foll'ows: "Although the current evidence is not sufficient to conclude that passive or involuntary smoking causes lung cancer in nonsmokers, the evidence does raise concern about a possible serious publlic health problem." (1982). The ambiguity of this statement underscores the difficulty of separating reality from zeal. CONCLUSION In the final analysis, if one makes amends for the intrusion of advocacy in, the design, interpretation, and publicity given to various studies, it is clear that uncertainty about the health effects of passive smoking stiill prevails. This clearly is not for want of trying, as many people and organizations have strong interest in the results of such research. But what needs to be stated is that, despite numerous and extensive trials, available evidence has not been found that a massive public health problemiattributable to passive smoking!exits. Clearly, whatever problems may be associated with passive smoking are likely to be small compared to other publlic health problems faced'today. This, of course, is not to say smoking may not have dramatic adverse effects for certain, narrow segments of the susceptible population, but in such cases intervention is easy and forthright. Studies will obviously continue to explore this field, but it is a foregone prediction that except for special circumstances and special matches of heavy exposure and'suscepti'ble populations the likelihood of finding future correlations of passive smoking exposure an& significant publ'ic health problems is negligible. Passive smoking must be considered withih the wider scope of air pollution in general, especial!ly as it relates to indoor environments, an issue that has been recently and broadly analyzed by Spengler and Sexton (1983) and Lebowitz (1983'). 03735116 Without a sense of proportion and perspective, researchers risk diverting prodigious amounts of goodwill, work, and' scientific credibility toward issues whose soluti'on is likely to be unproductive, compared to other issues that are momentarily out of the public eye but of vastly greater health significance.

C The public health community and the attending engineering professions will eontinue to experience the heavy emotional pressures that are likely to animate the case of passive smoking for a long time to come. Hopefully, their decisions and choices will be influenced by sober restraint, as they bear the responsibil'ity of allocating and utilizing vast, but still limited, national resources. Aronow, W.S. 1978. "Effective of passive smoking on angina pectoris" New Engl J of Med 299, pp. 896-897. Badre, R.; Guillerm, R.; Abrani, NI.; Bourdin, M.; and Dumas, C. 1978, "Atmospheric pollution by smoking" Ann Pharm Fr 36, pp. 443-452. "Breathing other people's smoke"' 1978. (Editorial) Br Med J 2', p. 453. Chappel, S.B. and Parker R.J. 1977. "Smoking and carbon monoxiide levels in enclose&public places in New Brunswick" Can J of Public Hlth 68, pp. 159,1611. Comstock, G.W.; Speizer F.E.; Ferris, B.G.,Jr.; and Burrows, B. 1977. "A comparisoniof self-completion vs. personal interviews of three structured respiratory disease questionnaire in smoking, age and sex matched groups of adults" Presented at the 8th International Scientific Meeting!, International Epidemiiologic Association, p. 66. Comstock, G.W.; Meyer, M.B.; Helsing, K.J.; and Tockman, M.S. 1981. "Respiratory effects of household exposures to tobacco smoke andigas cooking" Am Rev Resp Dis 124, pp. 143-148'. Cuddelback, J.E.; Donovan, J.R.; and Burg, W.R. 1976. "Occupational' aspects of passive smoking" Am Ind Hyg Assn J, May, pp. 263-267. Dahms, T.E.; Bolin J.F.; and S1!aviin, R.G. 1981. "Passive smoking. effects on bronchical asthma" Chest 801, p. 530. Fischer, T.; Weber, A.; and Grandjean, E. 1978. "Air polllution due to tobacco smoke in taverns" Int Arch Occup,EnvironiHlth 41, pp. 267-280. Garfinkel, L. 198!11. "Time trends in lung cancer mortality among nonsmokers and a note on passive smoking" J Natl Cancer Inst 66, pp. 1061-1066. Gori, G.B. et al, 1978. Cigarette smoking and airline piilots, Bethesda, Maryland: National Institutes of Health. Hirayama, T. 1981. "Non-smoking wives of heavy smokers have a higher risk of lung cancer: a . 203. Repace, J.L. and'Lowrey, A.H. 1980. "Indoor air pollution, tobacco smoke, and public health" Science 208, pp. 464-472'. Shepherd', R.J.; Coll'ins, R.; and Silverman F. 1979. "Passive exposure of asthmatic subjects to cigarette smoke" Environ Res 20', pp. 392-402. Smokin and health: A report to the Surgeon General, 1979. Alanta, Georgia: Center for Disease ontro , 11-1-11-40. study from Japan" Br Med J 282, pp. 183-185. Lebowitz, M.D. 1983. "Health effects of indoor pollutants," Ann Rev Public Hlth, 4,. Lee, P.N. 1982. "Passive smoking" Food Chem Toxicol 20, p. 223. Lehnert, G. 1981. "Krank durch passiv-rauchen?" Muench Me&Wschr 123, p. 485. ~

Spengller, J.D and Sexton, K. 1981. "Indoor air pollution: A public health perspective" Science 221(4605), pp. 9-16. The heallth consequences of smoking. cancer. A report of the SurgeoniGeneral, 1982. Washington D.C.: Department of Health and Human Services. Trichopoulos, D.; Ka1andidi, A.; Sparros, L.; and McMahon, B. 198'11. "Lung cancer and passive smoking" Int J Cancer 27, pp. 1-4. Weber, A. an6 Fischer, T. 1980'. "Passive smoking at work" 1980. tnt Archi Occup Environ Hllth 47(3), pp..209-21. White, J.R'. and'Froebi, H.F. 1980. "Small-airways dysfunction in nonsmokers chronically exposed to tobacco smoke" New Engl Jiof Med 302, pp. 720'-i32. i