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o PDCICFI46M THE BUILD UP AND DECAY OF AMBIENT CIGARETTE SMOKE COMPONENTS BY P.D. CASE /f Introductlon When examining the question of ambient cigarette smoke from an analytical chemistry standpoint, (which is how the question is going to be addressed during this presentation), there are effectively two ways to developing an understanding in this area. The first relates to monitoring ambient cigarette smoke in real life situations, (such as restaurants, bars, public transport etc.) which is the subject my colleague from B.A.T., C.J. Proctor, has addressed in his presentation. The second involves studying the build up and decay of ambient cigarette smoke under closely controlled environmental conditions of temperature, relative humidity, air circulation and ventilation which is the subject of this presentation. Therefore this presentation will be broken into two major areas, the first relating to a description of the pupose built smoke assessment facility constructed at our laboratories and the second describes some initial information gathered on the build up and decay of ambient cigarette smoke under one particular set of environmental conditions. Discussion Consequently slide I gives a simplified schematic diagram of the ambient smoke assessment facility purpose built on the roof of our research laboratories in Southampton. The overall design specification was arrived at after internal discussions with interested parties within our own organlsation~ and after briefing an external firm of heating and ventilating engineers. The fundamental characteristics of these rooms are that they CZD t.n CO r~D ClibPDF - www.fastio.com

-2- are purpose built and are supplied with independent air conditioning systems. The two rooms have a volume of 25m3 and are mirror images of one another with no windows, lighting being provided by fluorescent tubes. Air is introducted from the air conditioning units in the plant room and passes into a plenum wall cavity. This cavity has perforated steel grilles on the front and the air passes through these grilles across the room and is exhausted back via an identical steel grille and plenum to the air conditioning unit. ,f The other walls and ceilings of the rooms have a painted plaster finish, the paint being impervious to give an easily cleaned down surface. The flooring is constructed of heavy duty non slip PVC again to give an easily cleaned down surface. These surfaces do not preclude future studies involving the use of furnishings, carpets, curtains etc., which can be added and removed as necessary. The sniff boxes are effectively small chambers through which air is fed and returned from the exhaust plenum via a small fan and allows for subjective assessments to be made, if required, without people entering either of the two rooms whilst experiments are in progress. Both rooms have 'air locks' on them to prevent cross contamination of the laboratory with respect to both smoke plus temperature and relative humidity levels set in the rooms. It should be stressed that the 'air locks'~ the rooms themselves and the air conditioning units are not totally gas tight and leakage does occur, details of which are supplied later. Part of the philosophy behind constructing two rooms was to enable simultaneous testing of different cigarettes under identical environmental CID C~ CXD ClibPDF - wvvvv.fastio.com

-3- conditions or testing the same cigarettes under differing environmental conditions, For a11 the analytical experiments described in this presentation, smoking was carried out in room 2 with samples being taken via bulkhead unions in the wall seperating room 2 from the laboratory area, ¸,i-¸ The make up of the conditioning units located in the plant room is shown in slide 2. Before describing the function of the various pieces of equipment that make up the air conditioning unit it is important to appreciate the difference between the ~erms of ventilation and air change rate which will be used throughout this presentation. Ventilation is ehe percentage of fresh air (from outside) which is drawu into the air conditioning plant and hence into the rooms, with an equal percentage being expelled from the system. Air change rate is the number of times air passes around the air conditioning system and rooms in a given time e.g. 30 air changes per hour. The role of the various pieces of equipment that make up the air conditioning unit is as follows:- a) Mixing box - to produce a homogenous mixing of the air returning from the room with fresh air being drawn in from outside. b) c) Heater units - effectively to warm up the fresh air being drawn In from outside when the external conditions are below those set in the rooms. Coarse filter - to remove large particulate material (I0 microns CO ClibPDF - vvww.fastio.com

- 4 - or larger) being drawn in from outside. This unit can be removed for cleaning or removed completely if required. d) Electrostatic filter - for removal of particulate material (between 0.i and I0 microns) present in the air, the mode of operation is similar to that used for mainstream electrostatic precipitation. This unit can be turned off or on or if needs be it can be removed from the system. e) Carbon filter - used for the removal of organic vapour present in the air. If this unit is not required for operation, dampers effectively by pass It so air does not pass over the carbon beds, Again these units can be removed. f) Cooling unit - used to provide both cooling of the air if low temperature work is to be carried out and it can be used to reduce the relative humidity level, by condensing out moisture present in the air. Essentially this is a tube arrangement through which an anti- freeze mixture at I°C passes. The air then passes across the external surface of the tube to give both the cooling required and the condensation of any moisture that is present. g) h) Reheat unit - to warm up if needed~ the air to the temperature set within the rooms. This is done by passing hot water through a set of tubes on the outside of which fins are present to increase the surface area of contact. Humidifier unit - to increase the relative humidity if required, to the level set in the room. This is achieved by injecting steam via a lance into the air conditioning unit. t.n CO ClibPDF - www.fastio.com

-5- Additionally, (but not shown on slide 2) are two variable speed fans one of which supplies air to the room and the other extracts alr. Finally dampers are used to control the level of ventilation supplied to the rooms. Bavlng constructed the facilities determination of the operating characteristics was undertaken and slide 3 shows the calibration curve obtained for air change rate versus fan speed setting. This was undertaken by taking a matrix of air flow measurements across the various ducts leading to and exiting from the system using a pitot tube or hand held anemometer and then carrying out the appropriate conversions into volume flow per unit time interval. Clearly it can be seen that the calibration curve is non-linear and lacking somewhat in sensitivity and consequently some caution has to be exercised when setting up various experimental conditions° The use of fans with more linear calibration characteristics would be advantageous, additionally flow measuring systems (critical flow orifice plates etc.) in the system along with uncongested ducting would have been an advantage. There is no effect on the air change rate versus fan speed calibration on going from 0 to 100% ventilation. Variation in ventilation is achieved by motor driven dampers and in order to determine the level of ventilation achieved tracer gas studies were undertaken. The resultant calibration curve for room 2 is given in slide 4. Again a non linear response is produced and some variation in results are seen at high set levels of ventilation, due to the fact that the motorised dampers do not move to exactly the same position when a particular level of ventilation is set. Consequently ventilation levels are checked before each experiment is carried out by using the previously mentioned tracer gas technique. Additionally, the minimum level of ventilation achieved is approximately 7% due to natural leakage within the air conditioning units and rooms themselves, 0 0 CO Ox ClibPDF - www.fastio.com

-6- The overall operating characteristics of the rooms are defined in slide 5. Additionally heating and cooling of the room is achieved by air movement through the overall system and with low levels of air movement (i.e. low air change rates) the question of temperature and realtlve humldity stability arises, however few problems are observed in this area after the conditions have inltlally been set. r Thus, having established the operating characteristics of the rooms, a standard king size flue cured cigarette was selected to observe the effects of build up and decay of ambient cigarette smoke, one set of envlronental conditions being used. These being:- a) b) c) d) Temperature - 21.5 + l'C Relative humidity - 55 ~ 5Z Ventilation - 10Z Air change rate - 30 air changes per hour The cigarettes were allowed to smoulder on a rotary Borgwaldt RM20 smoking engine with only a lighting puff being taken. The mainstream particulate matter being trapped on a cambridge filter pad and the vapour phase being exhausted from room 2 via the bulkhead nnlon previously described, Continuous monitoring of particulate matter (using a plezo balance) carbon monoxide, carbon dioxide (using non dispersive infra red) oxides of nitrogen (using chemiluminesence) and hydrocarbons (using flame ionization) was undertaken. Slide 6 gives typical build up and decay characteristics for particulate matter and carbon monoxide. A number of interesting points arise from these plots:- J O CD ~m CO ClibPDF - w\,"4vv.fastio.col]l

a) -7- There is a rapid build up of the components monitored for as the cigarettes are allowed to smoulder. This reaches a maximum just after the cigarettes are extinguished. h) The decay of the components illustrated can be described on the basis of first order kinetics and slide 7 shows the time taken for the components illustrated in slide 6 plus nitric oxide to decay to half their ~axlmum values. Comparison of the particulate matter decay time with that for carbon monoxide and nitric oxide gives evidence to suggest that particulate matter is removed more rapidly under this set of conditions than are gas phase components. This suggests that Impaction, precipitation and deposition of particulate matter is occurring. The gas phase components being removed by the effect of ventilation and air change rate. Nitric oxide is removed more rapidly than carbon monoxide, due to its conversion to nitrogen dioxide. This data is independent of the number of cigarettes smoked but will depend upon the air change rate and ventilation level set. Raving looked at the build up and decay characteristics of ambient cigarette smoke the effect of smouldering different numbers of cigarettes was assessed and the results are illustrated in slide 8. ~n this instance the maximum values for various components are recorded. The results show for the majority of components increasing the number of cigarettes brings about a corresponding increase in the components of interest. Differences do exist but it should be remembered that a small sample of smoke is being taken from a large volume (unlike conventional mainstream smoking). All the results are corrected for background readings and the maximum background readings detected are recorded. The maximum background values C C ~r t J" Oc C~ ClibPDF - vvww.fastio.com

-8- for carbon monoxide and carbon dioxide correspond with maximum vehicle traffic movement on a main arterial road running out of Southampton, which passes close to our research laboratories. Additionally Threshold Limit Values (TLV's) (which are published annually by the American Conference of Governmental ~ndustrial Hygienists) which is "the time weighted average concentration for a normal 8-hour work day and a 40 hour work week, to which nearly all workers may be repeatedly exposed, day after day, without adverse effects" are not exceeded for any of the parameters even when 20 cigarettes are smouldered simultaneously. However when two or more materials (which have individual TLV's) are present within an environment their combined effect may be considered as additive as displayed in slide 9, where C is the concentration of one component and T is the corresponding TLV value for that component. If this summation exceeds unity then the TLV of the mixture, as defined by the American Conference of Industrial ~yglenlsts, should be considered as being exceeded. Thus from slide 9 with approximately 12 cigarettes being smouldered simultaneously one can exceed this value. However it is extremely unlikely that this situation would ever arise in practice, i.e. having twelve cigarettes being smouldered simultaneously in a room of 25m3 volume. In addition to undertaking a series of experiments in which differing numbers of cigarettes were smouldered under identical environmental conditions a reproducibility study was undertaken in which the same number of cigarettes were simultaneously smouldered under identical conditions on a number of occasions. The results are illustrated in slide I0. The precision of the measurements is extremely good, however the particulate matter level recorded is somewhat higher than the results indicated in 0 0 ¢.n CO ClibPDF-www.fastio.com

-9- slide 8 and this is in this exercise the particulate matter monitor was placed inside the room and not outside as previously described. The reason for the difference in carbon monoxide levels is probably due to s slightly dlfferenZ elgarette construc=ion being used. Examination of this data and experimental design shows some limitations, the first being that the particulate level burden found in the rooms does not equate when multlplied by the room volume to the level that would be expected on the basis of the sidestream yields from the same cigarette. This paratlcular problem does not manifest itself when the carbon monoxide, carbon dioxide and nitric oxide results are examined in a similar fashion. Needless to say this discrepancy is still being investigated. Additionally, no specific tobacco smoke marker has been examined in this study. Currently we are developlng a technique similar to that described by Muramatsu (and used by my colleague in his presentation) for the measurement of nicotine in ambient smoke but we are experiencing similar problems as those described for particulate matter with the technique at present, and again this discrepancy is being investigated. Conclusion In conclusion B.A.T. has developed an ambient smoke assessment facility, the characterlstlcs of which have been described, and these facilities have been used to galn an initial impression of the build up and decay characteristics of ambient cigarette smoke. As with all research programs, problem solving and experimental work is continuing. 0 0 t2n 0 ClibPDF-www.fastio.com

SLIDE l SIMPLIFIED SCHEMATIC PLAN VIEW i ii i ii OF B.A.T. AMBIENT SMOKE ASSESSMENT FACILITIES • i n ,, i • i , t -- -- A.L. = AIR LOCK S.B. -- SNIFF BOXES .n i SERVICE CORRIDOR PLANT ROOM uJ • • ~='1~ "1='---- m i~ 911----'==--" ROOM 1 ROOM 2 OFFICE A.L S. B. A,L!i ~ m LABORATORY 161S~SOOI DIRECTION OF AIR FLOW I