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Indoor Air Quality Scientific Aspects of Environmental Tobacco Smoke and Indoor Air

Indoor Air Ouality Summary This overview of literature on indoor air quality suggests that at most, tobacco smoke has only a minor influence upon normally ventilated indoor environments compared to common household or work- place sources, such as stoves, heaters and furnishings. Yet tobacco smoke, because it is so easily identifiable, has become a target for those who apparently want a quick, simple solution~ to the problem of indoor air pollution. Environmental to- bacco smoke can be visible in poorly ven- tilated areas. However the concentrations of substances derived from tobacco smoke in indoor air with normal ventila- tion are so low, that they are difficult to determine even with highly sensitive methods and equipment. Whilst it is not at all valid to compare exposure to smoke from ETS with that of active smoking due to the qualitative and quantitative dif- ferences in the composition of ETS it is possible to give an impression of the amounts of exposure involved by meas- urements of nicotine and particulate mat- ter. These measurements indicate that it would~take hundreds of hours of exposure to ETS to be exposed to the "equivalent" of a single cigarette. The persistence of visible tobacco smoke in a room is an indicator of poor ventilation and that the building's ventila- tion system needs improvement. Inadequate ventilation arises when the amount of 'fresh' air is insufficient to dilute the level of indoor constituents, and results in increases in the concentration of fungal and bacterial spores, and dusts and chemicals from other sources. Many com- plaints about indoor air quality have been traced to building contamination and in- adequate ventilation whether or not smo- kers are present. The claim that ETS is the major source of indoor air pollution is not supported by numerous recent studies. Introduction Until relatively recently, concern about indoor air quality was largely restricted to occupational exposure in the workplace. It has become appreciated that members of the public are exposed to a wide range of substances contaminating the air in their homes and in other buildings.1 There is an increasing realisation that little is known about many of the substances commonly found in indoor air where people may spend 80-90% of their time.2 Indoor contaminants are mostly produced by human activities or from building ma- terials. Indoor air quality is determined~by the air quality outside, by emissions with- in the building and by the ventilation rate and number of occupants. The overriding problem is, however, that because of en- ergy considerations ventilation in build- ings and houses has been reduced causing a gradual increase of various substances which may result in adverse health ef- fects.3 The benefit of any energy savings achieved by reducing ventilation may have to be set against a deterioration in indoor air quality4s and, particularly when heating and insulation are inad'equ- ate, by dampness from condensation and its consequent effects on health and ma- terials.6 Environmentai Tobacco Smoke The scientific literature indicates that, except under experimental or unrealistic conditions, ETS does not have a signifi- can,t~ influence on the quality of indoor air. It is frequently suggested that side- stream smoke, or the smoke from the burning end of the cigarette, contains much higher amounts of certain consti- tuents than mainstream smoke, or the smoke inhaled by smokers. However, dis- cussions of the relative amounts of com- ponents in~ mainstream and sidestream smoke is not relevant to the issue of ETS because it fails to take into account that sidestream smoke is immediately diluted in the surrounding air. The impact of ex- tensive dilution on sidestream smoke in room air cannot be over-emphasised. Scientists have estimated that under nor- mal, realistic conditions, the quantity of various constituents in ETS are only a tiny fraction - from 1/100th to 1/1000th - of those found in sidestream smoke.g In ad- dition, there are a number of physical differences between mainstream and side- stream smoke. For example, sidestream smoke has a higher pH (i.e. is less acidic)) than mainstream smoke, the particle size of sidestream smoke is smaller than that of mainstream smoke and the temperature of sidestream smoke is lower than that of Page 1

Indoor Air Ouality mainstream smoke. These characteristics account for the qualitative differences be- tween mainstream and sidestream smoke 9 The potential, toxicity of ETS has been assessed in a number of studies.10-14 These studies typically tested the body fluids of non-smokers exposed to ETS for mutagens, or substances capable of alter- ing the genetic structure of cells. Al- though it can be argued that the scientific literature on this subject is very limited, and that the laoratory tests employed are crude, the studies reported no mutagenic activity attributable to ETS exposure in the body fluids of non-smokers. Animal inhalation experiments using sidestream smoke or, constituents of side- stream smoke are also inconclusive. 15,16 German scientists exposed rats and ham- sters to very hi& levels of sidestream smoke during a 90,.day inhalation experi~ ment.15 The researchers reported no sig- nificant physiologieali effects on the tissues of the animals: In his comprehens- ive review of the literature on suspected pulmonary carcinogens, Dr Domingo Aviado observed that none of the consti- tuents ini sidestream smoke which have been identified as potentially carci- nogenic has induced pulmonary cancer in animals under experimental conditions. 16 A comparison is often made between sidestreatn and mainstream smoke consti- tuents, or sidestream to mainstream smoke ratios, to support claims about ETS. (A ratio obtained by dividing the amount of a constituent in sidestream smoke by the amount of that same consti- tuent in mainstream smoke. For example, a ratio of 2 for nicotine would indicate that there is twice as much in sidestream as in mainstream smoke). However, such a ratio is derived from laboratory measure- ments taken from the burning ends of cigarettes using small volume laboratory apparatus. Given these conditions, it is not surprising that some levels of sidestrearn smoke constituents may be greater than those in mainstream smoke. These ex- perimental techniques do not take into account the impact of dilution which oc- curs under realistic settings. A number of constituents are typically cited in the literature to demonstrate the contribution of ETS to the indoor air. These include carbon monoxide, particu- lates, nicotine and other substances. How- ever, the use of one or any combination of such constituents to determine ETS levels presents many problems. For example, although methods for sampling and ana- lysis of individual components have been developed, there is at present no com- pletely satisfactory and uniform proce- dure for measuring ETS.17,18 The findings of studies which measure consti- tuents in experimental conditions (e.g. in unventilated chambers) over-exaggerate the potential effect of ETS on indoor air and have little, if any, similarity to those studies which attempt to measure ETS in realistic settings. And finally, very few of the constituents which have been used as a surrogate measure for ETS are charac- teristic of ETS alone. Other sources, such as oil heaters, coal and wood stoves, insu- lation materials and furnishings and motor vehicle exhaust fumes from outdoors often generate substances at levels greater than those found in ETS. Carbon Monoxide The scientific literature on carbon monoxide from environmental tobacco smoke contains numerous examples of studies conducted under unrealistic con- ditions. For instance, in one such experi" ment, 80 cigarettes and 2 cigars were burned during a 78-minute period in a small unventilated simulated~ conference room.19 In another case, 9 cigarettes were smoked one after another in an unven- tialted automobile.20 Not surprisingly, the levels of carbon~ monoxide measured~ in those unusual situations were very high. Regrettably, studies of that sort are often cited as conclusive evidence of the impact of ETS on ordinary room air. On the other hand, when carbon mono- xide from ETS has been measured under realistic conditions, its contributions have been determined to be minimal. 21-28 In 1987 scientists in the United Kingdom monitored carbon monoxide and other constituents in over 3 000 locations throughout the country.ii They reported that carbon monoxide levels did not differ significantly between smoking and non- smoking environments. Putting such studies into perspective, Hutcheon, in a review of the literature, noted: "Environ- mental studies suggest that tobacco smoke has little impact on the carbon monoxide content of the room air except under high- ly artificial conditions:"29 Page 2

Indoor Air Oual What then are the sources of carbon monoxide in~public places? Research has shown that the main sources in the out- door urban environment are motor ve- hicles and industrial processes,30 and~that indoor levels are affected by these outdoor sources, mainly through ventilation4 and by numerous activities such as cooking and heating, In fact, studies have indicated that gas stoves in kitchens and heatingg units are often major sources of carbon monoxide in homes.31-33 After their review of such studies, par- ticipantsat a Geneva symposium on ETS concluded that carbon monoxide from en- vironmental tobacco smoke "is not im- portant from a health point of view:"34 Similarly, researchers from the Lawrence Berkeley Laboratory in the U.S., who are otherwise critical of tobacco smoke, con- cluded that "based on theoretical and em- pirical results, carbon monoxide side stream emissionsfrorn cigarettes have often been over-emphasised."35 Particulates A paper published in 1980, in which the authors reported the results of their efforts to measure particles or particulates in the air of smoking and non-smoking areas, is often cited to support the claim that ETS is a major indoor pollutant.36 The authors, Repace and Lowrey, contend that the levels of particles they observed in the smoking areas were much higher than in the non-smoking areas. However, their study results are inconsistent with many others. For example, the average particle count attributed~ to ETS in their study was nearly twice as high as that determined in a study of 44 offices,28 and nearly three to five times higher than the average levels reported in other studies of office buildings, restaurants and residen- ces.28X-44 There are a number of explanations for the authors' apparent over-estimadon of ETS exposure. First, they selectively sam- pled environments such as meeting and game rooms, bars and sandwich shops which did not represent normal occup- ancy conditions and where particulate le- vels wouW likely be high regardless of the presence or absence of tobacco smoke. Second, through inapproprate testing methods, they incorrectly assumed all particles in the air arose from ETS. How- ever, as several researchers have noted, ETS typically contributes less than half to overall particle levels in indoor spaces. 45-47 In 1989, researchers using methods ca- pable of separating the contribution of ETS to particulates in office air showed in a study of smokers' offices that ETS was not the major source of particles and that the Repace and Lowrey data was a gross overestimate (by over 10 dmes).48 More- over, particles also are generated by people and their everyday routine acti- vities such as movement and cooking. 49-50 In addition to ignoring potential indoor sources or particles, the study has been criticised on other grounds. For exarnple,. Repace and Lowrey did not measure ven- tilation rates and they failed to calibrate properly their instrument prior to test- ing.50 Indeed, according to some authors,, the testing device they used "Mno longer recommended" for tobacco smoke meas- urements.17,i8 Repace and Lowrey implied that the particle levels attributed to ETS are poten- tially harmful to the health of non-smo- kers. However, an earlier study by Bouhuys and; co-workers found "no evi- dence that high total suspended particu- lates levels in homes with smokers were associated with increased symptoms or lung function loss among non-smokers in the same home."51 Binder and co-wor- kers found that respirable particulate le- vels in homes were "independent of the presence or absence of respiratory dis- ease."19 More recently, Lebowitz and co- workers reported on data which showed that respiratory symptoms in asthmatics were associated with total particulate le- vels indoors (e.g. dust), but not with the presence of tobacco stnoke.53-54 Nicotine Unlike mainstream smoke, virtually all of the nicotine found in ETS exists in the gas (vapour) phase of the smoke. (Nico- tine is found in the particulate phase in mainstream smoke.) It is therefore of limited use as a marker for total smoke exposure (vapour and particulate phases). Nevertheless, since environmental nico- tine is produced exclusively by burning tobacco, it is often used as an indicator of the amount of tobacco smoke in the envi- ronment. Studies which have used nico- tine in this way suggest that Page 3

indoor Air Ouality environmental tobacco smoke contributes little to the indoor atmosphere.24-28, 41-44,. 5$'60 For example, Hinds and First of the Harvard School of Public Health found very small amounts of nicotine in the at- mosphere of bars, bus and airline tenni- nals, restaurants, and cocktail and student lounges.57 In a 1980 publication, Hinds wrote that in public places, "the typical, average airborne concentration" of the to- bacco smoke to which the non-smoker is exposed is equivalent to a small fraction of a cigarette per hour. 63 French researchers, using a different method'of nicotine measurement to assess the amount of tobacco smoke in the at- mosphere, reported higher concentrations of nicotine than Hinds and First.55 How- ever, they still concluded that "smoking does not present a risk to non-smokers." In 1984 and 1987, Japanese re- searchers reported on the use of a personal nicotine monitor in a number of public places, including offices, restaurants, lob- bies, terminals and~ on public transport. They reported levels of nicotine exposure equivalent to one-thousandth (1/1000) to four one-hundreths (4/100) of a cigarette per hour.$9,60 In a more recent nationwide sampling survey in the United Kingdom, re- searchers monitored nearly 3000 sites in travel, work, home and leisure locations for arnbient nicotine, carbon monoxide and particle levels.28 Smoking was known to have occurred at almost half of those sites, yet in three quarters of the samples, nicotine levels were too low to be detected. Canadian researchers also re- ported levels of nicotine at or below levels of detection even in locations with recir- culated air from designated smoking areas.50 Nicotine, particulates and carbon monoxide were measured in air samples taken in 23 office buildings and 48 res- taurants in New York City. The scientists reported such low levels that a typical New Yorker would have to work for near- ly five working weeks, or dine for 400 hours, in order to be exposed to the nico- tine "equivalent" of one cigarette.41 In 1987, scientists from IT Corporation, a company specialising in the assessment and reduction of environmental substan- ces, repeated the New York study in of- fices and restaurants in Dallas, Texas and in Ottawa, Canada.42,43 They reported average nicotine exposure levels equival- ent to three one-hundredths (3/100) of a cigarette per eight-hour workday, and three one-thousandths (3/1000l of a ciga- rette during a one-hour meal.4 Research in the UK, measuring ETS in the smoking compartments of trains, showed extremely low levels of nicotine (equivalent to 0.007 of a single cigarette for a typical journey).61 Similar work revealed that allowing smoking on single deck buses had little impact on the air quality, with the air being full of diesel exhaust 62 In betting shops in the UK, nicotine levels were found to be 25 times lower (better) than government standards and again vehicle exhaust fumes were the major source of airborne substances.61 There is little to suggest that the small amount of nicotine to which a non-smoker may be exposed is related to human dis- ease. For example, two German scientists monitored several physiological respon- ses in non-smokers exposed to tobacco smoke under laboratory conditions.64 They concluded that the amount of nico- tine to which their subjects were exposed was too small to alter sensitive test meas- urements of heart rate, heart muscle trac- ing, blood pressure or skin temperature. Similar findings were reported in 1982 by a Japanese physiologist.65 In a study of non-smoking flight attendants, re- searchers measured exposures to nicotine during transpacific flights. The re- searchers concluded that the concentra- tions of nicotine achieved were so small that they were "unlikely to have physio- logic effects:"66 In 1986, researchers monitored levels of nicotine, carbon monoxide and particulates in 66 commer- cial flights in the U.S. They concluded that segregation significantly reduces the exposure of persons seated in the no- smoking sections to ETS.67 Other Constituents Other constitutents which have been identified in analyses of sidestream smoke are often assumed to contribute substan- tially to indoor air in the form of ETS. The most commonly mentioned constitutents include nitrogen dioxide, formaldehyde and volatile organic compounds. How- ever, these compounds are present in very small amounts in ETS and difficult to measure 68'7Q Recent studies report no correlations between ETS and levels of Page 4

Indoor Air 0ualky nitrogen dioxide and volatile organic compounds in residences and of- fices.48, 71,72 Indeed, research indicates that levels of these components generated from other ordinary sources (e.g. cooking stoves, heaters and buidling materials) are much greater than those contributed by cigarette smoking.68,73 Sick Building Syndrome Advocates of smoking restrictions in the workplace commonly argue that ETS exposure gives rise to a number of com- plaints, including headaches, nausea,, coughs, sore eyes and breathing difficul- ties. However, research indicates that this complex pattern of symptoms, the so- called 'sick building syndrome', com- monly occurs in modern office buildin~s whether or not smokers are present?4- Concern about the reportedly high in- cidence of sickness among people who work in sealed buildings, especially of- fices, has attracted considerable attention. The term 'sick building syndrome' has been accorded recognition by the World Health Organisation.77 The prevalence and overall effect of 'sick building syn- drome' are difficult to assess since most people occasionally suffer from some symptoms whilst at work, particularly headaches and chest complaints. Some papers suggest that up to 30% of new and remodelled buildings (with recirculating ventilation or air conditioning systems) have an excess of illness among staff and that up to 85% of staff in such buildings suffer from some symptoms.78-81 In general, according to Sykes, it is difficult to show a link between smoking and 'sick building syndrome' 78 The evi- dence, he states, "of field studies is incon- clusive and many researchers believe there is no link." Sterling and co-workers, in an extensive review of over 150 indoor air quality evaluations of office buildings compiled by U.S. government agencies, universities and others, concluded that smoking did not significantly affect either indoor atmospheres or the frequency of worker complaints and symptoms.75 They maintain that "the review of avail- able studies does not provide any objec- tive evidence that either pollution levels or patterns of health related complaints differ in some remarkable way between locations with or without smoking restric- tions." Similarly, in a review of 203 air quality investigations of government and business offices, schools and health care facilities by the U'.S. National, Institute of Occupational Safety and Health, the gov- ernment researchers concluded that tobac- co smoke played a contributing role in, only four of the buildings invesugated.74 A large majority of all complaints were traced to general building contamination and inadequate ventilation. A similar picture has emerged from a sample of 223 individual indoor air quality investigations of public and pri- vately owned office budildings in as much as ETS was implicated in onl 4 per cent of the buildings investigated.7~The inves- tigators traced the majority of indoor air quality problems in modem office build- ings to inadequate fresh aircirculation and to poorly maintained ventilation systems which act as breeding grounds for fungi, bacteria and other contaminants. References 1. WorldlHealth Organization, in "Air Quality Guidelines for Europe", WHO Re- gional Publications, European Series No. 23 Copenhagen 1987, p426. 2. United Nations Environment Pro- gramme/World Health Organization, in "As- sessment of Urban Air Quality Worldwide", United Nations Environmental Programme - Global Environmental Monitoring System. UNEP/WHO Government Expert Meeting,. Geneva, September 1988. Appendix 1. pp 81-88. 3. Royal Commission on Environmental Pollution, in "Tackling Pollution - Experi- ence and Prospects", 10th Report, Chairman Southwood„R., HMSO, London 1984. pp. 119-130. 4. World Health Organization, in "Health Aspects Related to Indoor Air Quality", Eu- ropean Series No. 21, Copenhagen 1979. 5. National Research Council, in "Indoor Pollutants", National Academy Press, Wash- ington, D.C., 1981. 6. Anon., "Mould Growth in Buildings - A Persisting Problem"; Building Estab- lishment News, No. 53, 2-4. Page 5

Indoor Air Quality 7. Sterling„T., et al., "Indoor Byproduct Levels of Tobacco Smoke: A Critical Re- view of the Literature," J Air Pollut Control Assoc 32(3): 250-259, 1982. 8. Nystrom, C. and C. Green, "Assessingg the Impact of Environmental Tobacco Smoke on Indoor Air Quality: Current Status," Presentation, ASHRAE Indoor Air Quality Conference, Atlanta, GA, April 21, 1986. 9. Adlkofer, F., "Biological Effects After Exposure To ETS," Indoor Air Quality: Symposium (Buenos Aires, National Acade- my of Sciences of Buenos Aires, 1989): 61- 76: 10. Hoepfner„1., et al., "Hydroxy-Phenan- threnes in the Urine of Non-Smokers and Smokers," Toxicology Letters 35(1):67-71, 1987'. 11. Husgafvel-Pursianinen, K., "Sister- Chromatid Exchange an&Cell Proliferation in Cultured Lymphocytes of Passively and Actively Smoking in Restaurant Personnel," Mutation Research 190: 211-215, 1987. 12. Scherer„G., et all, "Urinary Mutage- nicity After Controlled Exposure to Environ- mental Tobacco Smoke (ETS),"Toxicology Letters 35(1): 135-140, 1987. 13. Sonnenfeldd, G. and D. Wilson, "The Effect of Smoke Age and Dilution on the Cytotoxicity of Sidestream (Passive) Smoke," Toxicology Letters 35(l ): 89-94, 1987: 14. Sorsa, M., eu al., "Cytogenetic Effects of Tobacco Smoke Exposure Among Invol- untary Smokers," Mutation Res 222(2): 111- 116, 1989. 15. Adlkofer, F., et al:, "Exposure of Ham~- sters and Rats to Sidestream Smoke of Ciga- rettes: Preliminary Results of a 90-Day-Inhalation Study," Indoor and Am- bient Air Quality, eds: R. Perry and P. Kirk (London: Selper Ltd:,1988)` 252-258. 16. Aviado, D., "Suspected Pulmonary Car- cinogens in Envitonmental, Tobacco Smoke," Indoor and Ambient Air Quality, eds. R. Perry and P. Kirk (London: Selper Ltd., 1988): 141-146. 17. First, M., "Environmental Tobacco Smoke Measurements: Retrospect and Pros- pect," ETS-Environmental Tobacco Smoke: Report from a Workshop on Effects and Ex- posure Levels, eds. R. Rylander„et al., Eur J Respir Dis; Suppl. 133(65):9-16, 1984. 18. Jenkins, R. and M. Guerin, "Analytical Chemical Methods for the Detection of En- vironmental Tobacco Smoke Constituents," ETS-Environmental Tobacco Smoke: Re- port from a Workshop onEffects and Expo- sure Levels, eds: R. Rylander, et a1., Eur J Respir Dis, Suppl. 133(65): 33-46, 1984. 19. Russell, M. et al., "Absorption by Non- Smokers of Carbon Monoxide From Room Air Polluted by Tobacco Smoke," Lancet i:576-579, 1973. 20. Harke, H., et al., "Zum Problem des Passivrauchens 11. Untersuchungen iiber den Kohlenmonoxidgehalt der Luft im, Kraftfahrzeug durch das Rauchen von Ziga- retten (The Problem of Passive Smoking. ll. Investigations of CO Level in the Auto- mobile After Cigarette Smoking)," 1nt Arch Arbeitsmed 33(3): 207-220,1974. Transla- tion. 21. Anderson, G. and T. Dalhamn, "HWsor- iskema vid passiv rOkning (Health Hazards from Passive Smoking)," LBkartidningen 70(33): 2833-2836, 1973. Translation. 22. Bridge, D. and M. Com, "Contribution to the Assessment of Exposure of Nonsmo- kers to Air Pollution From Cigarette and Cigar Smoke in Occupied Spaces," Environ Res 5(2): 192-209, 1972. 23. Duncan, D. and P. Greavey, "Passive Smoking and Uptake of Carbon Monoxide in Flight Attendants," JAMA 251(20): 120- 21,1984. 24. Hugod, C:, "Passive Smoking," Ugeskr Laeger 143(34); 21,81-2184, 1981. Transla- tion.. 25. Jones, R. and R. Fagan, "Carboxyhemo- globin in Nonsmokers: A Mathematical Model," Arch Environ Health 30(4):184- 189, 1975.. 26. Klosterkotter, W. and E. Gono, "Zum Problem des Passivrauchens (The Problem of Passive Smoking)," Zbl Bakt Hyg, I abt orig 162 162:51-69, 1976. Translation. 27. Szadkowski, D., et al., Kohlenmonoxid- belastung durch Passivrauchen in Biiro- r9umen (Carbon Monoxide Levels From Passive Smoking in Offices),"' Inn Med 3(6):310-313,1976. 28. Kirk, P.W., et al., "Environmental To- bacco Smoke in Indoor Air,'"' Indoor and Ambient Air Quality, eds. R. Perry and P.W. Kirk (London: Selper Ltd., 1988): 99- 112. 29. Hutcheon, D., Statement, State of New ~' Jersey Public Health Council, Public Hear- O ing on Regulation of Smoking in Certain N Public Places, Trenton, New Jersey, Decem, ber 12, 1978'. ~ ~ O Page 6 ~ ~

Indoor Air ©uallty 30. Stewart, R., "The Effects of Low Con- centrations of Carbon Monoxide in Man," Environmental Tobacco Smoke Effects on the Nonsmoker: Report from a Workshop,, ed. R. Rylander, Scand J Respir Dis, Suppl. 91: 56-62, 1974. 31. Wade, W., "A Study of Indoor Air Quality," J Air Pollut Control Assoc 25(9):933-939,1975. 32. Yocom, J., "Indoor-Outdoor Air Quality Relationships," J Air Poliut Control Assoc 32(5): 500•520, 1982: 33. Cox, B.D. and M.J. Whichelow,'"Carb- on Monoxide Levels in the Breath of Smo- kers and Nonsmokers: Effect of Domestic Heating Systems," J Epidemiol Community Health 39:75-78, 1985. 34. Rylander, R., "Workshop Perspec- tives," ETS-Environmental Tobacco Smoke: Report from a Workshop onEffects and Exposure Levels, eds. R. Rylander, et al., Eur J Respir Dis, Suppl. 133(65);143- 145, 1984. 35. Girman, J. and G. Traynor, "Indoor Concentrations," J'Am Pollut Control Assoc 33(2): 89 1983. 36. Repace, J. and A. Lowrey, "Indoor Air Pollution, Tobacco Smoke and Public Health," Science 208: 464-472, 1980: 37. Weber,,A. and T. Fischer, "Passive Smoking at Work" In[ Arch Occup Environ Health 47: 209-221, 1980. 38. Sterling, T., et al., "Environmental To- bacco Smoke and Indoor Air Quality in Modem Office Work Environments," J Occup Med 29( l):57-62, 1987. 39. Giseke, J., et al., "Collection and Char- acterization of Airborne Particulate Matter in Buildings," ASHRAE Transactions. 84(1):572-589,1978. 40. Spengler, J., et al., "Long-tetm Meas- urements of Respirable Sulfates and Par- ticles Inside and Outside Homes," Atmos Environ 15:23-30, 198'1. 41. Press Release, "Study of Air Quality in 100 N.Y.C. Restaurants, Offices Shows To- bacco Smoke is Insignifcant Factor," The (U.S.) Tobacco Institute, December 10, 1986. 42. TT Corporation, Final, Report: Environ- mental Tobacco Smoke Survey, Dallas, Texas, Sur;jmitted to Tobacco Institute, Washington, D.C:, August 4, 1987. 43. Carson, J.R. and C.A. Erikson, "Results from Survey of Environmental Tobacco Smoke in Offices in Ottawa, Ontario," Envi- ron Technol Letters: 9: 501-508,,1988'. 44. Sterling, T., "ETS Concentrations Under Different Conditions of Ventilation and Smoking Regulations," Indoor and Am- bient Air Quality, eds. R. Perry and P.W. Kirk (London: Selper Ltd., 1988): 89-9& 45. Ogden, M.W. and K.C. Maiolo, "Col- lection and Analysis of Solanesol as a Tracer of Environmental Tobacco Smoke (ETS)," Indoor and Ambient Air Quality, eds. R. Perry and P.W. Kirk (London: Sel- per Ltd., 1988): 77-88. 46. Proctor, C.J., "The Analysis of the Con- tribution of ETS to Indoor Air," Indoor and Ambient Air Quality, eds. R. Perry and P. W: Kirk (London: Selper Ltd., 1988): 57- 66. 47. Eatough, D.J., et al., "Assessing Expo- sure to Environmental Tobacco Smoke," In- door and Ambient Air Quality, eds. R. Perry and P. W'. Kirk (London: Selper LtdL, 1!988): 131-140: 48. Proctor, C.J., et al ,"Measurements of Environmental Tobacco Smoke in an Air- conditioned Building",Environ Tech Lett., 10, 1003-1018; 1989. 49. First, M., "Constituents of Sidestream and Mainstream Tobacco Smoke and Mar- kers to Quantify Exposure to Them," Indoor Air and Human Health (Chelsea, Michigan: Lewis Publishers, 1985): 195-203. 50. Sterling, T., "Discussion - Tobacco Smoke,, Ventilation, and Indoor Air Quality," ASHRAE Transactions 88(1):911- 912„ 1982. 51. Bouhuys, A., et al., "Do Present Levels of Air Pollution Outdoors Affect Respir- atory Health?" Nature 276 (5687): 466-471, 1978. 52. Binder, R., et al., "Importance of the In- door Environment in Air Pollution Expo- sun:,"'Arch Environ Health 31(6): 277-279„ 1976. 53. Lebowitz, M.,'"The Effects of Environ- mental Tobacco Smoke Exposure and Gas Stoves on Daily Peak Flow Rates in As- thmatic and Non-Asthmatic Families," "ETS-Environmental Tobacco Smoke: Re- port from a Workshop on Effects and Expo- sure Levels, Eur J Respir Dis, Suppl. eds, R. Rylander, et al. 133(65): 90-97, 1984. 54. Lebowitz,,M., et al., "Respiratory Symptoms and Peak Flow Associated with Indoor and Outdoor Air Pollutants in the Southwest," J Air Pollut Control Assoc 35: 1154-1158,1985: Page 7

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