Indoor Air Quality and Ventilation Strategies in the Use of Combustion Space Heating Appliances in Housing

Transcription

1 Hiroshima J. Med. Si. Vol.43, No.4, , Deember, 1994 HIJM Indoor Air Qality and Ventilation Strategies in the Use of Combstion Spae Heating Applianes in Hosing Onny SETIANI Department of Pbli Health, Hiroshima University Shool of Mediine, Kasmi, Minami-k, Hiroshima 734, Japan (Diretor: Prof. Fmitaka YOSHINAGAJ ABSTRACT Indoor air qality (IAQ) in the se of ombstion applianes is important for adeqate evalation of air polltion health risks. Sine people spend most of their time inside bildings, espeially the elderly and hildren, their exposre to indoor air ontaminants an inrease health problems in the ommnity. Combstion materials emitted from ombstion spae heating applianes in hosing dring the winter may beome a serios problem to health, sine sores of ventilation are sally left losed to obtain a omfortable temperatre level. To evalate the IAQ and fators that may derease ombstion materials emitted from heaters, a stdy was done by sing a hose exposre model. The stdy fond that IAQ in an nventilated hose dring ombstion heater se was poor de to lak of fresh air. When sing a heater, natral ventilation shold be sed to dilte air ontaminants emitted from the heater. A onentration of arbon dioxide at abot 1 and a omfortable temperatre of 2 C old be maintained by applying natral ventilation of abot.12 m 2 dring the se of an nvented kerosene spae heater. However, ventilation also depends on the nmber of the opants and the wind veloity. The se of a steamer is also important to provide optimm hmidity levels withot elevating the respirable dst onentration above the aeptable limit. Key words: Indoor air qality (IAQ), Combstion materials, Natral ventilation, Hmidifiation IAQ is reeiving inreased attention from researhers and pbli health offiials as a ritial omponent of hman exposre to a variety of air polltants. An inreasing nmber of health and omfort problems in relation to IAQ have been reported dring the winter. Indoor air ontaminants are thoght to ase adverse effets spanning a range of hemial, physial and biologial sbstanes, in whih the onentrations are often higher than those fond otdoors 6 12 ). To evalate the IAQ and determine the effets from exposre to emissions from polltant sores, a stdy was done by sing a hose exposre model. There are many reasons why investigations of IAQ are essential for the adeqate evalation of air polltion health risks. Sine people spend 8-9% of their time inside bildings, indoor air ontaminants at any signifiant level is bond to lead to inreased levels of omplaint and possibly to health problems 2 4 ). Espeially for the elderly and infants, the exposre to indoor air ontaminants is still higher. IAQ may be adversely related to trends toward reded ventilation in bildings, inreased se of syntheti materials, and inreased reliane on nvented ombstion applianes for spae heating. In modern bildings and apartments, the reded air exhange rate between onditioned indoor air and nonditioned otdoor air an inrease the indoor onentration of polltants5 14). One type of indoor air polltion sore is nvented ombstion sed for spae heating, inlding nvented kerosene spae heaters, nvented gas applianes, wood stoves and fireplaes ). Combstion sores in homes an emit arbon monoxide and arbon dioxide, oxides of nitrogen, formaldehyde, organi omponds, nitros and other aids and partilate matter that may affet IAQ. High temperatres from spae heating applianes may also inflene the air hmidity and affet the onentration of respirable dst 8 ). The aim of this stdy was to identify indoor air qality in the se of ombstion spae heating applianes in hosing and the fators that may rede indoor air ontaminants. Correspondene to: Onny Setiani, Department of Pbli Health, Hiroshima University Shool of Mediine, Kasmi, Minami-k, Hiroshima 734, Japan.

2 164. Setiani METHODS IAQ dring the se of ombstion spae heating applianes in hosing was measred by sing a hose exposre model. One Japanese style apartment with 2 rooms (floor, areas of 32 m 2 and volmes of 8 m 3 ) loated in Hiroshima, Japan was sed for this stdy. The stdy was done in Febrary, IAQ measrements, inlding the temperatre, relative h:mj_dity, onentration of arbon dioxide, arbon monoxide and respirable dst were taken dring the se of kerosene spae heating applianes. Two ;types of nvented kerosene spae heater were sed in this stdy. Type I was an nvented kerosene spae heater that was eqipped with a fan, steamer and atomati temperatre ontrol (Toyostove, LCB3D). The other was an ordinary nvented kerosene spae heater. Eah experiment was ondted by sing the two kinds. of heater for for days. Measrements were taken 5 hors eah day ntil a nearly satrated onentration of arbon dioxide was ahieved. To stdy the role of fresh air in dilting the ombstion materials emitted from the heater, natral ventilation was introded for abot one minte dring heater sing time. This was intended to stimlate the effet of people going ot and opening the door for one or two mintes. Air qality sampling was taken randomly five times eah hor in a spae at the height between. 6 and 1. 5 m. The differenes between arbon dioxide and arbon monoxide onentration before and after sing natral ventilation were also measred. Before arrying ot the experiment, the air qality otside and inside the hose was also adjsted by opening all the doors and the windows for abot one hor. The effet of hmidifiation when sing the heater was also stdied. Air temperatre and relative hmidity were reorded with a battery-operated psyhrometer. Indoor arbon monoxide and arbon dioxide onentrations were measred by olorimetri detetor tbes (Kitagawa, 16G and 126 B). Conentrations of respirable dst were measred by a Sibata P-5H2 digital dst monitor, a diret reading instrment based on light sattering alibrated by the manfatrer to,3 µm partiles of steari aid. RESULTS Figre 1 shows that the onentration of arbon dioxide inreased qikly in the first three hors and then the inrease slowed ntil it approahed satration after five hors. However, the arbon monoxide onentration will ontine to inrease as the heater sing time is prolonged. There was a slight differene between the onentration of arbon monoxide and arbon dioxide in the se of two types of heaters. It was also fond that the average onentration of arbon monoxide was higher with the se of type II heater. g 2:: 2 C J 1:: 1 se s :tain CO level 3 4 Time (hors) Fig. 1. Indoor C2 and CO onentration dring the se of nvented ombstion spae heater applianes. <> ;!:::.. Type I heater (with fan and steamer) +;.& Type II heater (withot fan and steamer) ,-3 C2 ] 15 1 "' o Oldoor temperatre e Indoor lemperatre oo "o o... oo.. o :' B I Time f hor3 l Fig. 2. Average C2 onentration and temperatre level dring the se of kerosene spae heater appliane with treatment by several forms of natral ventilation (starting time 1. a.m.) Tl: window open for 2 min T2: door open for 1 min T3: window open for 3 min T4: by applying.24 sqare meters of natral ventilation dring the orse of the stdy (bathroom window) T5: by applying.12 sqare meters of natral ventilation dring the orse of the stdy (livingroom window) T6: by applying.24 sqare meters of natral ventilation dring the orse of the stdy (ross ventilation) Figre 2 shows the onentration of arbon dioxide, arbon monoxide and the indoor temperatre with treatment by employing several sores of natral ventilation, and different opening drations. The reslts showed that a derease of arbon dioxide and arbon monoxide onentration was appropriate to the width of the window and the length of time the window was open. A 2 15

3 IAQ in the Use of Combstion Heater , 55 l;- 5 '6.E :r:.., 45. qj "a> : <> Type I Heater(A) +Type 11 l;feater(b) , 6 1 e Temperatre (CC) <'>' E ' s O? t (!.).., *' : Relative Hmidity(%) B o TypelHea.ter(A) TypellHea.ter(B) Fig. 3. Linear regression vales of the relative hmidity as a fntion of the indoor temperatre in the se of type I and II heater. Type I heater (A): HUMIDITY = -.58 TEMP ; R =.63, n = 18, p<.1 Type II heater (B): HUMIDITY = TEMP ; R =. 72, n = 18, p<.1; where HUMIDITY is the relative air hmidity, TEMP is the indoor temperatre, R is the orrelation oeffiient, n is the nmber of measrements and p is the two tailed p vale of the slope. Fig. 4. Linear regression vales of the respirable dst onentration as a fntion of the relative air hmidity in the se of the type I and type II heater. Type I heater (A): DUST =.37 HUMIDITY +.24; R =.58, n = 18, p<.1 Type II heater (B): DUST =.1 HUMIDITY +.17; R =.73, n = 18, p<.1; where DUST is the respirable dst onentration, HUMIDITY is the relative air hmidity, R is the orrelation oeffiient, n is the nmber of measrements and p is the two tailed p vale of the slope. lower onentration of arbon dioxide dring the se of the kerosene heater was ahieved when sing ross ventilation or when both sides of the window were opened at the same time. Figre 3 shows the relationship between relative air hmidity and indoor temperatre dring the se of a ombstion spae heating appliane. The linear regression vales of the respirable dst onentration as a fntion of the relative air hmidity is also shown in Fig. 4. DISCUSSION In hosing sing a kerosene spae heater, IAQ is poor de to the high onentration of ombstion materials emitted by the heater. It was fond that the onentration of arbon monoxide in the se of type I heater was lower, althogh the onentration of arbon dioxide was almost the same. However, the onentration of arbon dioxide was still high when sing either type I or type II heaters, althogh a small ventilation above the stove was kept opened. This showed that the air exhange is insffiient to dilte the air ontaminants from ombstion sores. Carbon dioxide onentrations are properly sed in indoor air qality stdies as a rde indiation of whether or not an aeptable otdoor air ventilation rate is being provided to dilte air ontaminants. If the arbon dioxide level exeeds 1 and gaseos and partilate air ontaminants are not otherwise removed, there is a strong likelihood that the amont of otdoor air being provided to the opied spae is inadeqate to dilte air ontaminants. As was reommended by the Amerian Soiety of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standard , indoor arbon dioxide onentration shold not exeeds 1 to satisfy the opant's omfort needs 7 ). When sing ombstion applianes in hosing natral ventilation is reqired to dilte air ontaminants from ombstion sores. The level of ombstion emissions within a bilding an also be lowered by ontrolling the sores or improving ventilation 3 ). By sing ross ventilation and mehanial ventilation the onentration of air ontaminants an be dilted almost perfetly with fresh otdoor air. It was fond that the onentration of arbon dioxide did not exeed 5, althogh the heater was still being sed, bt the temperatre fell as a onseqene of too mh ventilation. By opening the window of abot.12 m 2, the onentration of arbon dioxide old be maintained at abot 1 withot dereasing the temperatre too mh. The average temperatre sing this natral ventilation old be maintained at abot 2 C, a omfortable indoor temperatre dring the winter. By opening the door or the window for one or two mintes as a simlation of people entering or leaving the hose, the onentration of air ontaminants was fond to derease, bt the onentration wold beome higher shortly after the sores of ventilation were losed again. Based on

4 166. Setiani a preliminary observation in the ommnity that doors and windows are sally left losed in winter, the reslting high onentration of indoor air ontaminants old threaten the health of opants. Opening the window for a few mintes eah hor as sggested on heater applianes is not always pratial. A better way to. dilte air ontaminants in hosing is by natral ventilation when sing ombstion applianes, nless heating, ventilation, and air onditioning (HVAC) systems are provided. It was fond that a arbon dioxide onentration below 1 old be ahieved by sing natral ventilation of abot.12 m 2 or abot.4 % of the floor area, and a better diltion rate old be reahed by sing natral ventilation of abot 1.1 % of the floor area. However, the se of a high ventilation rate in winter is not appropriate for energy onservation. The se of a heater also had an inflene to hmidity and the respirable dst onentration. As the temperatre inreases, relative hmidity and the respirable dst onentration derease. Althogh a hmidity derease was still aeptable in the first five hors, a prolonged dration of heater se might derease the hmidity still frther and problems related to hmidifiation wold inrease 1 ). By sing a steamer that fntions as a hmidifier, the aeptable hmidity an be ahieved dring heater se. Most people are omfortable when the hmidity at 2 C is between 4% and 6 %. Very high indoor hmidity levels, e.g., more than 7%, enorage the growth of mold and other mirobiologial ontaminants, whereas levels below 3% an ase drying of the mos membrane 1 ). However, the se of a steamer has only a minor effet on the onentration of respirable dst and does not elevate the respirable dst onentration above an aeptable limit. Conseqently, the se of a steamer when sing a spae heating appliane is better for maintaining optimm hmidity levels. If it is felt that the air has to be hmidified, this is best done with steam ll). In onlsion, this stdy shows that indoor air qality in a losed hose dring the se of ombstion spae heater applianes is poor de to the lak of fresh air. The onentration of air ontaminants in hosing an be minimized by sing ventilation dring heater se. An adeqate intake of otdoor air is needed to dilte air ontaminants emitted from the heater. For ventilation strategies, at least abot.12 m 2 of natral ventilation is needed when sing a kerosene spae heater appliane. However, ventilation also depends on the nmber of the opants and wind veloity. With sh natral ventilation, arbon dioxide onentration in hosing an be maintained at abot 1, assming that the air exhange is adeqate to dilte air ontaminants withot dereasing the temperatre too low and does not threaten the opant with health hazards. Withot sing a steamer, the relative hmidity is still aeptable as long as the heater is not sed for more than five hors. ACKNOWLEDGEMENTS The athor is very gratefl to Prof. Fmitaka Yoshinaga and Dr. Masayki Kakehashi for their advie and gidane dring this researh and mansript preparation, and to Dr. Akihiko Seo, Dr. Satoko Tsr for giving enoragement and sggestions dring the orse of this stdy. The athor also wishes to thank Miss Noriko Kanda for her assistane in the preparation of instrments. REFERENCES 1. Hodgson, M Field stdies on the sik bilding syndrome. Ann. N. Y. Aad. Si. 641: Kreiss, K The epidemiology of bilding-related omplaints and illness. Philadelphia, Hanley and Belfs In. Vol.4, No Lambert, W.E. and Samet, J.M The role of ombstion prodts in bilding-assoiated illness. Philadelphia, Hanley and Belfs In. Vol.4, No Loftness, V. and Hartkopf, V The effets of bilding design and se on air qality. Philadelphia, Hanley and Belfs In. Vol.4, No Lyles, W.B., Greve, K.W., Baer, R.M., Ware, R.M., Shramke, C.J., Croh, J. and Hik, A Sik bilding syndrome. Soth. Med. J. 84: Moshandreas, D.J Combstion sores: emissions, effets, haraterization and ontrols (E2C2). Ann. N.Y. Aad. Si. 641: Morey, P.R. and Shattk, D.E Role of ventilation in the asation of bilding related illnesses. Opational Mediine: State of the Art Reviews. Philadelphia, Hanley and Belfs In. Vol.4, No Norbak, D., Torgen, M. and Edling, C Volatile organi omponds, respirable dst, and personal fators related to prevalene and inidene of sik bilding syndrome in primary shools. Br. J. Ind. Med. 47: Norbak, D., Mihel, I. and Widstrom, J Indoor air qality and personal fators related to the sik bilding syndrome. San. J. Work Environ. Health. 16: Qinlan, P., Maher, J.M., Alevantis, L.E. and Cone, J.E Protool for the omprehensive evalation of bilding-assoiated illness. Philadelphia, Hanley and Belfs In. Vol.4, N o Robertson, A Sik Bilding Syndrome. The Pratitioner. 233: Sexton, K. and Wesolowski, J.J Safegarding indoor air qality. Environ. Si. Tehnol. 19: Tihenor, B.A. and Mason, M.A Organi

5 IAQ in the Use of Combstion Heater 167 em1ss1ns from onsmer prodts and bilding materials to the indoor environment. JAPCA. 38: Traynor, G.W., Apte, M.G., Carrthers, A.R., Dillworth, J.F., Prill, R.J., Grimsrd, D.T. and Trk, B.H The effets of infiltration and inslation on the sore strengths and indoor air polltion from ombstion spae heating applianes. JAPCA. 38: