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'THF. ELECTRICITY C(~~~IL RESEARCH CENTRE ~ ECRC/M870 COyFTDE'3'f I111. VENTILATION REQUIREMENTS IN ROOMS OCCUPIED BY SMOKERS: A RF.VIEW .(,V1 I _ _ ~ i i A_:,Lt,I 1U'H ltlrU L1LL lU 1'JUI•.., vftL t ,BRUNiLRf;T'T, GW . Ventilation requirements in rooms occupi-," ed by smokers: a review F:lectr Counc Res 0(0'19) : '1-56 ecem~ber, 1- 9~ 75 ,The fresh air needed to dilute cigarette smoke to an acceptable increasing the irritation. nose irritation thamsmokers but eye irritation affects both. Humidity has an important influence on irritation, lower humidities level is the dominant criterion for ventilation design of buildings. The literature is reviewed and brought to a common basis of dilution air per cigarette. Non-smokers are more sensitive to smell' and Health criteria are compared with the compounds released in the cigarette smoke. Carbon monoxide is the most critical if the EPA recommended limit of 9ppm is accepted. .-Nine cubic metres of 3 ,fresh air are needed per cigarette. Preferred values of 26m /h per person agree well with current ventilation guides. The.little data available suggests a wide difference between people and care must therefore be taken in choosing mean votes for an 1-1 assessment of smoke. If the smoke is considered acceptable by the average person, then 267% of the population are likely to find it objectionable. Some allowance for this spread of sensitivities Application of the research data to offices shows a particular problem related to office size. If the office contains a hundred or more people then the population in it can be considered representative of the working population i.e. containing 50% smokers. -1-

ECRC/M810 If the office only contains a small number of people then it is likely to contain a wide variety of smokers/non-smokers/heavy z. . smokers/light smokers from time to time. Some provision to cater for different needs of such offices is suggested. Finally comparison of British and.American recommendations agrees reasonably well with the smoking habits of the two countries in normal large offices. The British IHVE Guide 1970 treats smoking in the same way as body.odours andrelates it to personal space. The ASHRAE Guide more correctly treats it as a simple contaminant. The preferred ventilation criteria would be related to body odours in crowded areas and smoking requirements in more spacious areas. This Memorandum is published as part of the Electricity Council's Research Programme and any technical query on the contents or permission to reproduce any part of it should be addressed to the Author. December, 1975. -2-

v- ECRC[M870 CONTENTS Page N BACKGROUND 4 THE INFLUENCE OF ROOM CONDITIONS ON ODOUR 13 THE INFLUENCE OF SMOKE ON THE PASSIVE SMOKER 15 SMOKE GENERATION' 5 ci IDENTIFICATION OF SMOKE DISCOMFORT ODOURLESS GASES: CARBON MONOXIDE AND CARBW DIOXIDE 19 COMPARISON OF GUIDES (SEE APPENDICES 1& 2) 23 DISCUSSION 25 DESIGN IMPLICATIONS 28 11. .. CONCLUSIONS 30 I REFE REN CES 32 ACKNOWLE DGEMENTS TABLES 1 - 8 3- 43 44-52 53 L

F.CRC/,M870 Insulation techniques to minimise the heat loss through the fabric of a building exist and are being widely used. The other type. of heat loss is through ventilation.Current research is se.ekit:F low cost solutions for controliled'ventilation and the key questior: is how much ventilation is neede&. One criteria is the dilutlion of cigarette smoke to an acceptable lievel of comfort and health. This note surveys the availablie literature• in four fields. The first is that of smoke generation by the cigarette, the second is the sensitivity of people to smoke, the third is the toxicity of smoke to the passive smoke and the fourth is an examination of ventilation needs. t, V

duri.ng"the puff period. Those mainstream products not absorbed When a cigarette is smoked the products of combustion are divided between the mainstream products and the sidestream ones. The :nainstream products are drawn through the cigarettt by th:r smoti.r.Y by the smoker are expelled in subsequent breaths. The :;idEstream smoke is released directly into the room air during the smouldering combustion stage which occurs between puffs. Most research has concentrated on identifying and quantifying the products of the mainstream smoke to enable the toxic compounds to be reduced. Only recently has interest revived in the sidestream smoke so that the problems of the non-smoker working in a smoky room can be examined. Machine simulated smoking tends to use a.35 ml puff of two second generation at a. rate of one puff a minute. The butt length is usually 23'or 30 mm and the tobacco has a 10% moisture content. This characterizes the smoker. In general more tobacco is burned during the smoulder period than the puff period (20% 110% more in the sidestream). ,Reviews of smoke generation by Wynder and Hoffman 1967 and . Hoegg 1972 show the complexity of the combustion process. ECRC/M870 The to . sidestream smoke released depends upon the smoulder.rate. Tobaccos with high smoulder rates such as Turkish types have over three , ' the nicotine in the sidestream to increase with increasing moisture times the tobacco burned during the smoulder period than the puff periodi(Johnson 1973). Hensen & Haley 1935 and Neurath 1964 showed content in the tobacco. Smoker habits will also influence the balance ,between sidestream and mainstream. Deep, frequent puffs will increase the mainstream smoke at the expense of the sidestream. finding over a hundred times more in the sidestream and tiorne ten times inure pyridine. lle also noted that hydrogen cyanide was The general agreement that the sidestream and mainstream combustion products are proportionred according to the amount of tobacco burned ii, smouldering and puffing does no,: af:ply to certain cc,mpounds. Rogen 1929 found mcure ammonia itt llr,. :,idestreara. 1973 ngrcE.i, -S. I +

ECRC/M870 principally in the mainstream. The particular probl~em of oxides of nitrogen was raised by Haagen-Srdit, Brunelle & Hara 1959 and studied by Bokhovemet al. 1961.` Bokhoven found equal volumes of nitric oxide and nitt:agPn dioxide which amounted to 0.04 mg and 0.51 mg respectively. Galuskinova 1964 searched for benzpyrene, a product of cigarette smoke, and found it varied with the number of cigarettes smoked in rooms. More recently attention has been directed towards the carbon monoxide dangers of cigarette smoke. More carbon monoxide is released in the sidestream than the mainstrem. Brunneman and Hoffman 1974 showe6how the mainstream carbon monoxide and carbon dioxide increased with time as the cigarette was smoked. The quantity per puff doubled from first to last puff. Russell, Cole, Idle and Adams 1975 studied a wide range of British cigarettes and'foun&the mainstream yiel&of carbon monoxide varied from 5-20 mg per cigarette for conventional cigarettes, with a higher value of 28 mg for a semi-synthetic one. In the low nicotine ' cigarettes the carbon monoxide increased with nicotine content of the tobacco but there was no clear relationship for the high nicotine ones. A summary of the work on carbon monoxide generation Analyses by Hobbs 1956 indicated acrolein to be an important product of mainstream smoke. Work by Weber 1975 using a smoking machine in an environmental chamber showed significant amounts of acrolein. Data on acrolein in cigarettes is given in Table 1. Illustrations of general chemicals in smoke are given in Table 2 and the differences between authors of the major compounds are .shown in Table 3. This analytical work on smoke defines yields in terms of a cigarette. The concentrated sidestream compoutuls -aeed diluting to an acceptable level for health a.nd comfort. Treating sm.ke as a simple contaminant means that the necessary dilution can be most clearly expressed in terms of fresh air per cigarette. This -6-

ECRCJ148'70 also has the advantage of comparing the subjective Lesults of different authors on a common basis. It has two disadvantages. The.first is that the early American cigarettes contained one gram'of tobacco while British filter cigarettes contain approximately 600 mg. Fortunately the smoking habits in America are such~th<.t a large stub is usually discarded unlike British praccice. The tobacco content of current American Filter cigarettes is also lower ('875 mg) than in earlier years. The se_ond potential problem is the wide difference in tar and nicotine between brands which can vary by an order of magnitude (Department cff Hedl'th 1974). There has been a significant reduction in tar content over recent years but fortunately the tar and nicotine contents of the current market leaders are similar, Table 5, Figure 1. The smoke in rooms is the sum of the sidestream smc,!<e and the exhaled smoke. Mitchell 1962'found that 20-50% by wcight of the mainstream smoke was.retained in the smoker even when~no smoke adsorbed and 87-96% of the nitrogen oxides. carbon monoxide. They found between 82-87% of the carbon monoxide retained the smaller were the exhaled particles. Bokhoven & Niessen 1961 measured the absorption of nitrogen oxides and was inhaled. Retention was 82% when inhaled'for five seconds and reached'97Z after thirty seconds. Thelonger the smoke was V . -7- i .

IDENTIFICATION OF SMOKE DISCOMFORT ECRC/M870 The three types of problem~associate&with tobacco smoke are poorr visibility, unpleasant odour and personal distress through headache or irritation of the eyes or throat. There is common agreement amongst non-smokers of the types of irritation, with eyes being the most sensitive, Table 6. The visibility criteria is dependent upon the viewing position. Cinemas, where the direction of view is in line with the projection beam, are relatively insensitive to smoke cloud. Enclosed sports arenas where the principal lighting is directly over the action do have to consider the appearance of the smoke haze. Leopold 1945 studied this by experimenting with the ventilation . of a large sports arena. He measured the acceptability of the atmosphere by recording the impressions of five trained individuals who included one non-smoker and one heavy smoker. The recommended 3 ventilation for an acceptablie appearance was 32-53 m/h/person. Less than 207, of a sample of the spectators were smoking. This would be approximately 26 m3/cigarette. When the fresh air was reduced to 20-34m3/h/person the cloud became objectionable ;(approx. 17 m3/cig.). Eye irritation was experienced at the slightly 3 lower flows of 19`31 m /h/person (approx. 16 m3/cig.). The nature of the activity means that spectators enter and leave at the same time, enjoying two hours of entertainment. They rapidly acclimatise to the odours and no problems of unpleasant smells were noted. Odour sensitivity and'irritation to eyes tend to change with time. The sense of smell rapidly adapts to a new odour while the irriltation effects become stronger with exposure. Yaglou 1955 investigated three types of response to people smoking in a room. One type was that of an observer freshly entering the room, one was the of non-smokers who had been exposed to tobacco smoke for 2-4 hours and the final type was the response of the smokers'themselves. -8- i

I I I I 0 I I ECRC/M820 C Acceptable strength of the tobacco smoke was defined as one of moderate odour or irritation with little or no objection. Tiit: visitor required a dilution of 9m3/cigarette for acceptability. The comparable figure for the non-smoker was 5.5 m3/eigaroette. The smokers were unable to smelli the smoke odour and based their judgements on irritation of the eyes, nose and throat and .headaches. The dilution required for this was 4m3/cigarette. At smoke dilutions of lm3/cigarette and less the smoke odour was difficult to perceive by everyone, irritation becoming the major response (Figure 2). In an earlier study Yaglou 1937 (15) examined the disappearance characteristic of tobacco smoke odours once the smoking had stopped. Rather than naturally decaying, the od'our intensity of the stale tobacco smoke increased with time for the first hour or two and only then d'iminished (Figure 3). The practical implication of this is that rooms in which smoking is permitted' should be small in size and highly ventilated so that the residence time of the combustion products is kept as short as practicable. Yaglou. al'so measured the effectiveness of the air distribution system whi~ch was supplied through perforations near to the ceiling and air was the effectiveness of the air supply was down to 65% because of 3 occupants. At high air flow rates (550 m/h -14 air changes/hour) the by-passing of air straight into the exhaust. The effectiveness of the air distribution system should receive particular attention at high ventilation rates. Harmesen and Effenberger 1957 investigated room polluti~on and carefully graded air qual'ity in terms of chemical concentrations of nicotine, carbon monoxide and the physical concentration of particulates. They found'ithe quality slightly disagreeable to non-smokers at nicotine concentrations below lmg/m3. From Neurath's data (1964) this would mean dilutions of 4m3/cigarette for the sidestream component alone'. 3 extracted' at floor level. At low air flow rates (26ni /h ^' 0.65 changes/hour) the supply air mixed well with the room air and practically 100% effective in diluting the air around the room, I ( -9-

ECRC/M870 Keuhner 1953 used'a dilution principle to assess the odour strength of cigarettes. He found'that the odour of tobacco smoke was insensitive to the brand of cigarette, its burning rate or its freshness. Halfpenny & Starrett 1961 undertook a careful study on the ventilation needs for aircraft passengers. Likely contamination levels were assessed from specially undertakemfield surveys. Subjective assessments were made on a group of peopl'e sitting inside a simulated aircraft under a range of contamination conditions. The influence of charcoal filters on odour level was also investigated. The test procedure maintained a single smoke concentration for each test and the irritation level was recorded once the maximum steady response was reached i.e. after 25-30 minutes. Humidity wasuncontrolled, with the majority of experiments (80Z) carried out between 40-487 r.h. The range of humidity encountered varied from 24-59%. The conclusions showed irritation of eyes, nose and throat to be the comfort criteria since after a few minutes' adaptation observers were unable to detect tobacco smoke. Accepting their finding that an average Americancigarette burns 550 mg of tobacco we can interpret the results in terms same smoke concentration were large, Figure 4. Johansson & Ronge 1964 investigated the irritation effects of a room which was progressively filled' with smoke. The strongest irritation effects occurred under warm dry conditions. of 15.6 m3 fresh air/cigarette and objectionable levels were 6.9 m3/cigarette. Personal differences in irritation to the 26m /cigarette, moderate irritation occurred at smoke dilutions of fresh air per cigarette. Threshold irritation occurred at 3 The three responses studied were eye irritation~, nose irritation and air quality. Air quality was the most sensitive factor. Non-smoker.s were much more sPnsitive than smokers requiri.ng approxima.tely 5.5 m3/'cigarette dilution air. Smokers accepted a dilution of 1.6 m3/cigarette. Eye irritation was the next most sensitive factor with li~ttle difference in response between smokers and ncn--smokers. 1'hreshol&irritation occurred at R i