AP03_6.vp 1 Introduction The increasing requirements for indoor air quality in buildings need more exact criteria in order to ascertain the real condition of the environment and to allow better optimi- zation of its level, to remove “sick building” symptoms, i.e. to get the real comfort within a building. Human physiology research makes evident that the Weber-Fechner law applies not only to noise perception, but also to the perception of other environmental components. Based on this fact, new decibel units for odor component representing indoor air quality in majority locations have been proposed: decicarbdiox dCd (for carbon dioxide CO2) and decitvoc dTv (for total volatile organic compound TVOC) – see Part 1 of this paper. Equations of these new units have been proved by applica- tion of a) experimental relationships between odor intensity (representing odor perception by the human body) and odor concentrations of CO2 and TVOC, b) individually measured CO2 and TVOC levels (concentrations) – from these new deci- bel units can be calculated and their values compared with decibel units of noise easured in the same locations. To be able to evaluate the indoor air quality in practice, we need to establish limits or, more exactly, admissible and toler- able ranges for both unadapted and adapted persons (P). 2 Carbon dioxide The starting points of these values are based on various studies (e.g. [23]) whose results are listed in Table 2.1 and in Fig. 2.1. See also Tables 1.2 and 1.3 (p. 24, 25) and Fig. 1.4 (p. 26) in Part 1. The optimal value overwhelmingly corresponds PD � 20 %. A better value of PD � 10 % could be prescribed © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ 31 Acta Polytechnica Vol. 43 No. 6/2003 Indoor Air Quality Assessment Based on Human Physiology – Part 2. Limits M. V. Jokl In order to evaluate indoor air quality in practice it is necessary to establish limits, or more exactly, tolerable ranges for unadapted and adapted persons. The optimal value overwhelmingly corresponds to PD � 20 %. A better value of PD � 10 % could be prescribed for asthmatics and for persons with increased requirements, i.e. those allergic to the environment and operators in airport control towers and atomic power stations. A worse value PD � 30 % could be accepted as an admissible value. These values differ for unadapted and adapted persons (as introduced by BSR/ASHRAE 62-1989 R). The long-term tolerable value is the end of SBS range (for CO2 it is based on USSR space research, for TVOC on Molhave). The short-term tolerable value is the beginning of the toxic range (for CO2 it is taken from British Guidance Note EH 40/90; for TVOC from Molhave). Keywords: indoor air quality, odors, air changes estimation. No. Limit Value Source [mg�m�3] [ppm] [dCd] 1 875 485 0 threshold 5.8 % dissatisfied 2 1080 600 8 USAF warning USAF Armstrong Laboratory 1992 3 1110 615 9 un asthm. optimal? 10 % dissatisfied unadapted 4 1440 800 20 OSHA warning OSHA: Federal Register 1994 5a 1800 1000 28 optimal limit Pettenkofer 1858 5b 1800 1000 28 acceptable limit ANSI/ASHRAE 62/1989 5c 1800 1000 28 opt. long-term WHO/EURO:Air Quality Guidelines 1992 6a 1825 1015 29 un optimal limit 20 % dissatisfied unadapted 6b 1825 1015 29 un asthm. admissible? 6c 2000 1110 32 concentration of no concern for non industrial buildings WHO (Levy 1992) Table 2.1: Various limits and ranges for CO2 concentrations: un � unadapted persons, asthm. � asthmatic persons, ? � for values of asthmatic persons there is no experimental background (analogy to TVOC is presumed) for asthmatics and for persons with increased requirements, i.e. those allergic to the environment and operators in airport control towers and power stations (especially atomic power stations). This is analogous to the TVOC limits (see later). 32 © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ Acta Polytechnica Vol. 43 No. 6/2003 No. Limit Value Source [mg�m�3] [ppm] [dCd] 7a 2160 1200 35 opt. short-term WHO/EURO:Air Quality Guidelines 1992 7b 2200 1225 36 ad asthm. optimal ? 10 % dissatisfied adapted 8 2830 1570 46 un admissible 30 % dissatisfied unadapted 9a 4350 2420 63 ad optimal limit 20 % dissatisfied adapted 9b 4350 2420 63 ad asthm. admissible? (BSR/ASHRAE Standard 62-1989R) 10a 5035 2800 68 limit for direct gas fired air heat- ers BS 5990: 1981 of British Standard Institu- tion 10b 5035 2800 68 limit for direct gas fired air heat- ers BS 6230: 1982 of British Standard Institu- tion 11a 6300 3500 77 long-term acceptable Env. Health Directorate, Canada 1989 11b 7000 3890 81 concentration of concern for nonindustrial buildings WHO (Levy 1992) 11c 7360 4095 83 ad admissible 30 % dissatisfied adapted 12a 9000 5000 91 long-term exposure limit 8 hrs Guidance Note EH 40/90 from HSE of GB 12b 9000 5000 91 average concentration for indus- trial and nonindustrial buildings Commission de la Sante et de la Securite du Travail 12c 9000 5000 91 long-term tolerable USSR space research (SBS range ends) 13a 18000 10000 118 maximum allowable concentration for ind. and nonind. buildings Commission de la Sante et de la Securite du Travail 13b 18000 10000 118 short-term tolerable USSR space research 14a 27000 15000 134 short-term tolerable toxic range begins 14b 27000 15000 134 short-term expos. lim. 10 min Guidance Note EH 40/90 from HSE of GB Un A 875–1825 485–1015 0–29 Optimal range Un A1 875–1110 485–615 0–9 Asthm. optimal range? Un A2 1110–1825 616–1015 10–29 Asthm. admissible range? Un B 1826–2830 1016–1570 30–46 Admissible range Un C 2831–9000 1571–5000 47–91 Long-term tolerable (SBS) range Un D 9001–2700 5001–15000 92–134 Short-term tolerable range Un E � 27001 � 15001 � 135 Intolerable range Un A 875–4350 485–2420 0–63 Optimal range Un A1 875–2200 485–1225 0–36 Asthm. optimal range? Un A2 2201–4350 1226–2420 37–63 Asthm. admissible range? Un B 4351–7360 2421–4095 64–83 Admissible range Un C 7361–9000 4096–5000 84–91 Long-term tolerable (SBS) range Un D 9001–27000 5001–15000 92–134 Short-term tolerable range Un E � 27001 � 15001 � 135 Intolerable range Table 2.1: Various limits and ranges for CO2 concentrations: un � unadapted persons, asthm. � asthmatic persons, ? � for values of asthmatic persons there is no experimental background (analogy to TVOC is presumed) (continue) A worse value of PD � 30 % could be accepted as an admissi- ble value. These values differ for unadapted and adapted persons (as introduced by BSR/ASHRAE 62-1989 R). The long-term tolerable values, which are quoted in occu- pational health standards and studies, are reached in build- ings with sick building syndrome (SBS). Short-term tolerable values are those at the beginning of the toxic range both for unadapted and adapted persons. Also the lowest, detectable value is the same for unadapted and adapted person (P). For unadapted persons optimal (PD � 20 %) and admissi- ble (PD � 30 %) values are 1015 ppm and 1570 ppm (Fig. 2.2), i.e. 29 dCd and 46 dCd. For adapted persons the curve must first be added into the diagram (Fig. 2.2) as follows: © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ 33 Acta Polytechnica Vol. 43 No. 6/2003 Fig. 2.1: The proposed CO2 limits: optimal admissible and tolerable values, the psycho-physical scale slightly modified by Fanger (1988) (ad � adapted persons, un � unadapted persons) For unadapted persons the equilibrium equation is valid (1) � � � � R G P P i e e � � � � � � � CO CO CO CO 2 2 2 2 10 3600 19 1000 36 1015 7 6 � � �. .5 [l�s�1�p�1](1) where RP � 7 5. l � s �1 � p�1, prescriptive outdoor air require- ment for unadapted persons [9]; GPCO2 19� 1� h �1 � p�1, CO2 load caused by a sedentary person (see Table 2.2); � iCO mg m2 1015 3 � � � , CO2 indoor air concentration for 20 % dissatisfied unadapted persons (see Fig. 2.2); � eCO2 310� ppm, CO2 outdoor air concentration as a result of Eq. (1). For adapted persons the same Eq. (1) is valid, but the prescriptive outdoor air requirements for them, according to [9], is only 2.5 1 � s�1� p�1 CO2 load caused by a sedentary person and outdoor CO2 concentration remain the same, i.e. G�CO2 19� 1 � h �1� p�1, � eCO2 310� ppm. So CO2 indoor con- centration � iCO2 can be calculated: � � RP i � � 19 3600 2 5 2 � CO . [l � s�1� p�1] (2) where � iCO2 2420� ppm, i.e. for 20 % dissatisfied adapted persons, CO2 indoor air concentration can be raised from 1015 ppm to 2420 ppm. Presuming the same character of the curve, i.e. � �� ���CO k PD2 5 98 4 � � �ln . [ppm] � �2420 310 20 5 98 4� � � �k ln . we get for adapted persons: � �� ���CO PD2 167 350 5 98 4 � � �. ln . (3) For adapted persons optimal (PD � 20 %) and admissible (PD � 30 %) values are 2420 ppm and 4095 ppm, i.e. 63 dCd and 83 dCd. Optimal (PD � 10 %) and admissible (PD � 20 %) values for asthmatics could be, for unadapted persons: 615 ppm, 9 dCd (PD � 10 %) and 1015 ppm, 29 dCd (PD � 20 %); and for adapted persons: 1225 ppm, 36 dCd (PD � 10 %) and 2420 ppm, 63 dCd (PD � 20 %). More experimental data are required. The long-term tolerable value (5000 ppm, 91 dCd; the end of the SBS range) is based on USSR space research; the short-term tolerable value (15000 ppm, 134 dCd; the begin- ning of the toxic range) is taken from British Guidance Note EH 40/90 as described previously. 34 © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ Acta Polytechnica Vol. 43 No. 6/2003 Fig. 2.2: The percentage of dissatisfied sedentary subjects as a function of the carbon dioxide concentration above outdoors Activity TVOC [�g � h �1 � p �1 ] 3) CO2 [l � h �1 � p �1 ] Sedentary, 1–1.2 met1) 0 % smokers 5140 19 20 % smokers2) 10290 19 40 % smokers2) 15430 19 100 % smokers2) 30870 19 Physical exercise Low level, 3 met 20580 50 Medium level, 6 met 51440 100 High level (athletes), 10 met 102890 170 Children Kindergarten, 3–6 years, 2.7 met 6170 18 School,14–16 years, 1–1.2 met 6690 19 1) 1 met is the metabolic rate of a resting sedentary person (1 met � 58 W� m�2 skin area, i.e. approx. 100 W for an average person) 2) average smoking rate 1.2 cigarettes/hour per smoker, emission rate 44 ml CO/cigarette 3) converted olf values presented in EUR 14449 EN Table 2.2: Pollution load caused by occupants No Limit Value Source [�g � m�3] [dTv] 1 50 0 threshold 5.8 % dissatisfied (1.0 by Yaglou Psycho-Physical Scale) 2 85 12 un asthm. optimal 10 % dissatisfied unadapted (EUR 14449 EN) 3a 200 30 un optimal limit 20% dissatisfied unadapted (EUR 14449 EN) old dwelling houses old office buildings Table 2.3: Various limits and sranges for TVOC concentrations © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ 35 Acta Polytechnica Vol. 43 No. 6/2003 No Limit Value Source [�g � m�3] [dTv] 3b 200 30 un asthm. admissible 4 250 35 ad asthm. optimal 10 % dissatisfied adapted 5 300 39 target guideline Seifert (1990) 6 360 43 un admissible 30 % dissatisfied unadapted (EUR 14449 EN) new dwelling houses new office buildings 7a 500 50 level of concern National Health and Medical Research Council of Aus- tralia (Dingle, Murray 1993) 7b 580 53 ad optimal limit 20 % dissatisfied adapted 7c 580 53 ad asthm.admissible 8 1040 66 ad admissible 30 % dissatisfied adapted 9a 3000 89 long-term tolerable SBS range ends 9b 3000 89 multifactorial exposure range limit Molhave (1990) 10a 25000 135 short-term tolerable toxic range begins 10b 25000 135 discomfort range limit Molhave (1990) No Limit Value [�g � m�3] [dTv] Un A 50–200 0–30 Optimal range Un A1 50–85 0–12 Asthm. optimal range Un A2 86–200 13–30 Asthm. admissible range Un B 201–360 31–43 Admissible range Un C 361–3000 44–89 Long-term tolerable (SBS) range Un D 3001–25000 90–135 Short-term tolerable range Un E 25001 136 Intolerable range Un A 50–580 0–53 Optimal range Un A1 50–250 0–35 Asthm. optimal range? Un A2 251–580 36–53 Asthm. admissible range? Un B 581–1040 54–66 Admissible range Un C 1041–3000 67–89 Long-term tolerable (SBS) range Un D 3001–25000 90–135 Short-term tolerable range Un E 25000 136 Intolerable range Table 2.3: Various limits and ranges for TVOC concentrations (continue) 36 © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ Acta Polytechnica Vol. 43 No. 6/2003 Fig. 2.3: The proposed TVOC limits: optimal, admissible and tolerable values. The psycho-physical scale slightly modified by Fanger (ad � adapted persons, asthm � asthmatic persons, un � unadapted persons) 3 Total volatile organic compounds The starting points of these values are based on various studies whose results are listed in Table 2.3 and in Fig. 2.3 (see also Tables 1.3 and 1.4 (p. 25 and 28) and Fig. 1.4 (p. 26) in Part 1). The philosophy behind the various limits is the same as previously presented for CO2. For unadapted persons optimal (PD � 20 %) and admissible (PD � 30 %) values are 200 �g � m�3 and 360 �g � m�3, i.e. 30 dTv and 43 dTv. For adapted persons the curve must first be added into the diagram (Fig. 2.4) as follows. For unadapted persons the equilibrium equation (4) is valid: � � � � R G B B i e e � � � � �TVOC TVOC TVOC TVOC36 5140 36 200 7 5 . . . � � � [l�s�1�p�1](4) where RB � 7 5. 1�s �1 �p�1, prescriptive outdoor air require- ment for unadapted persons [9] GBTVOC � 5140 �g�h �1 �p�1, TVOC load caused by sedentary person (see Table 2.2); � iTVOC � 200 �g � m �3, TVOC indoor air concentration for 20 % dissatisfied unadapted person (see Fig. 2.4); � eTVOC �10 �g � m �3, TVOC outdoor air concentration, as a result of Eq. (4). For adapted persons the same Eq. (4) is valid, but the prescriptive outdoor air requirement for them, according to BSR/ASHRAE 62-1989 R, is only 2.5 l � s�1� p�1; TVOC load caused by a sedentary person and outdoor air TVOC con- centration remain the same, i.e., GBTVOC � 5140 �g�h �1� p�1, � eTVOC �10 �g � m �3. So TVOC indoor air concentration � iTVOC can be calculated: � � RB i � � � 5140 3 6 10 2 5 . . � TVOC [l � s�1� p�1] (5) where � iTVOC � 580 �g � m �3, i.e. for 20 % dissatisfied adapted persons TVOC indoor air concentration can be raised from 200 �g � m�3 to 580 �g � m�3. Presuming the same character of the curve, i.e. � �� �� TVOC k PD� � �ln .5 98 4 � �580 20 5 98 4� � �k ln . [�g � m�3] we get for adapted persons, preferring again �p as it was with CO2, � �� ��� TVOC � � � �46000 5 98 104ln .PD [mg � m�3] (6) For adapted persons optimal (PD � 20 %) and admissible (PD � 30 %) values are 580 �g�m�3 and 1040 �g�m�3, i.e. 53 dTv and 66 dTv. Optimal (PD � 10 %) and admissible (PD � 20 %) value for asthmatics could be for unadapted persons: 85 �g�m�3, 12 dTv (PD � 10 %) and 200 �g�m�3, 30 dTv (PD � 20 %) and for adapted persons: 250 �g�m�3, 35 dTv (PD � 10 %) and 580 �g�m�3, 53 dTv (PD � 20 %). Besides asthmatics these values are also recommended for people with increased re- quirements: those allergic to the environment or those having responsible positions – operators in airport control towers and power stations, especially atomic power stations. The long-term tolerable value (3000 �g�m�3, 89 dTv; the end of the SBS range) and short-term tolerable value (25000 �g�m�3, 135 dTv; the beginning of the toxic range) are based on [36]. 4 Conclusions 1. The new units – decitvoc and decicarbdiox – can be a new basis for a constituent mutual interaction study. 2. The units dCd and dTv can be estimated by the direct measurement of TVOC and CO2 concentrations – instru- ments can be calibrated directly in the new units. 3. The units dCd and dTv, as indoor air quality criteria, allow an optimal range definition. 4. The units allow an optimal range definition (so-called asthmatics optimal range) for persons with increased requirements (e.g. those allergic to indoor air quality, operators in airport control towers, power stations etc.). 5. The unit allow the admissible range definition (for both healthy and allergic persons). 6. The units allow definition of the SBS range (correspond- ing to the long-term tolerable range). 7. The units allow the estimation of dangerous indoor air quality (corresponding to the short-term tolerable range, see Figs. 2.1 and 2.3). 8. The units allow the efficiency of air cleaners (and other indoor air-improving measures, e.g. using low polluting building materials) (see [30]) to be expressed, i.e. what is the decrease of air contamination after application? References See presented at the end of Part 3 (p. 44). Prof. Ing. Miloslav V. Jokl, DrSc. phone: +420 224 354 432 email: miloslav.jokl@fsv.cvut.cz Department of Engineering Equipment of Buildings Czech Technical University in Prague Faculty of Civil Engineering 166 29 Prague 6, Czech Republic © Czech Technical University Publishing House http://ctn.cvut.cz/ap/ 37 Acta Polytechnica Vol. 43 No. 6/2003 Fig. 2.4: The percentage of dissatisfied sedentary subjects as a function of total volatile organic compound concentra- tion above outdoors