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Microbiological indoor air quality in subtropical areas
Eavironmtnt International, Vol. 19, pp. 233-239, 1993 Printed in the U.S.A. All fights reserved.
0160-4120/93 $6.00 +.00 Copyright 01993 Pergamon Press Ltd.
MICROBIOLOGICAL INDOOR AIR QUALITY IN SUBTROPICAL AREAS Chih-Shan Li and Yu-Mei Kuo Division of Environmental Health Science, Institute of Public Health, College of Medicine, National Taiwan University, Taipei, Taiwan, R.O.C.
E19212-208 M (Received 17 December 1992; accepted 13 February 1993)
In Taiwan, a subtropical country, bioaerosols are regarded to be quick to grow, because of high relative humidity and high temperature all year around. Field investigations of microbiological indoor air quality were performed in six apartments in the Taipei area. Two-stage Andersen viable impuctors were used to determine the concentration, genus, and respirable fraction of fungi indoors and outdoors. The fungi characteristics in living rooms, bedrooms, kitchens, bathrooms, and outdoors were compared. The concentrations of indoor and outdoor fungi in different locutions of the six apartments were found to vary widely. The geomentric mean concentrations of indoor and outdoor fungi were higher than I000 CFU m "3. Moreover, more than 80% of indoor and outdoor fungi were observed to be respirable. In addition, the ratios of indoor to outdoor fungi concentrations were too low to indicate the presence of any indoor fungi sources. In some homes, the concentrations of the asthma-related fungi genus, Aspergillus, Penicillium, and Cladosporium, were found to exceed 500 CFU m -3.
INTRODUCTION
al. 1990). Currently, it is suggested by the American Conference of Governmental Industrial Hygiene (ACGIH 1986) that bioaerosol concentrations higher than 500 CFU m "3 be considered as a sign of the presence of a building-related air pollution source. It was pointed out from bioaerosol investigations in Finnish homes (Reponen et al. 1989; Nevalinen et al. 1991), that high concentrations of airborne fungal spores and bacterias were related with health complaints from the residents. In addition, the relationship between the microbiological concentrations and children's respiratory health problems was investigated during summer and winter seasons in 150 homes ( S u e t al. 1990). It was found that hay fever
In recent years, indoor air quality has become an important issue, because of the occurrance of the "sick building syndrom" and the factthat most people spend more than 80% of their time indoors (NRC 1981). Indoor bioaerosols have been well recognized as the major cause of symptoms in reports of, for example, absences in classrooms and officesor lower productivity in hospitals and occupational environments (Burge 1991; Chatigny et al. 1989). Moreover, it was found that the fungi concentrations inside the buildings significantlyexceeded the outdoor levels, being higher than 500 C F U m "3 in six residences and offices in Minneapolis (Reynolds et 233
234
has a significant correlation with indoor fungi, such as Cladosporium, Epicoccum, and Yeast. Furthermore, children's respiratory symptoms and wheezing and/or asthma complaints of school-age children have shown a statistically significant association with indoor Aspergillus concentrations. From the previous reports mentioned above, many of the building-related illnesses had been identified, and bioaerosols were found to be responsible for the observed health effects. Taiwan, a subtropical country, has warm weather (20-37°C) and high relative humidity (65%-90%) all year round. From an investigation of the influence of temperature and relative humidity on fungal growth (Pasanen et al. 1991), it was found that temperature of 21-30°C and relative humidity of 75%-92% could induce fungal germination and growth more quickly. Therefore, it is considered that bioaerosols are much easier to grow in subtropical areas. It is necessary to evaluate whether there is a microbiological indoor air quality problem in Taiwan. In this investigation, field characterizations of indoor and outdoor fungi in six Taipei apartments were conducted. Two-stage Andersen viable impactors were used to determine concentrations and the genus of nonrespirable and respirable fungi in living rooms, bedrooms, kitchens, bathrooms, and outdoor environments. Therefore, it was possible to evaluate the fungi characteristics in different indoor locations and outdoors. MATERIALS AND METHODS
The field evaluation of microbiological indoor air quality in six Taipei apartments was performed in May and June of 1992. Fungi were sampled with two-stage Andersen viable impactors on malt extract agar (ACGIH 1986). These samplers can classify fungi into nonrespirable (>4.7 lxm) and respirable (<4.7 Ixm) fractions at a constant flowrate of 28.4 L/min. The sampling locations included living rooms, bathrooms, bedrooms, kitchens, and outdoor areas of the six homes with duplicate measurements in each place. During the field measurements, the sampling time ranged from 20 sec to 1 rain. The temperature and relative humidity were recorded. The samplers for indoor and outdoor measurements were located 1.2m to 1.5 m above the floor to simulate the human breathing zone. The plates were incubated at 250C for four to six days to measure the fungi. The biological m e a s u r e m e n t s w e r e c l a s s i f i e d i n t o
Alternaria, Aureobasidiura, Cladosporium, Curvularia, Drechslera, Asperillus, Penicillium, Paecilomyces, Fusarium, Trichoderma, Scopulariopsis, Acremonium,
C.-S. Li and Y.-M. Kuo
Geotrichum, Monilia,Rizopus, Mucor, Syncephalastrum, Yeast, and others; or they were not classified. Original concentrations of airborne fungi measured in different locations of the six residences (in CFU m "3) were transformed by natural logarithm to approximate normality in the analysis. A SAS statistical p a c k a g e was utilized for s t a t i s t i c a l analysis. RESULTS AND DISCUSSIONS
The field investigation of indoor and outdoor fungi was conducted in six apartments in Tapei for evaluating whether bioaerosols are an indoor air quality problem in Taiwan. During the field measurements, temperature and relative humidity were found to be in the range of 21-3 I°C and 70%-85%, respectively. The concentrations of indoor and outdoor fungi in different locations of six apartments were observed to vary widely. The average indoor fungi concentrations were in the range of 140-3200 CFU m -3 in the living room, 420-1800 CFU m "3 in the bathrooms, 4382870 CFU m -3 in the bedrooms, and 508-3000 CFU m -3 in the kitchens. In addition, the average outdoor concentrations ranged from 400 CFU m "3 to 4200 CFU m'3. It was found that indoor fungi concentrations in Tapei were significantly higher than those observed in San Francisco (Macher et al. 1991) and Edinburgh (Flannigan et al. 1990), as well as comparable to those found in Finnish moldy homes (Reponen et al. 1989; Nevalinen et al. 1991). Furthermore, the observed maximum concentrations of indoor and outdoor fungi_in every case could be as high as 3500 CFU m "3" The overall average with standard deviation and geometric mean of the total fungi concentrations were found to exceed 1000 CFU m"3 in each sampling location of the six homes (as shown in Fig. 1). The fungi concentrations measured in June were found to be much higher than those observed in May. Moreover, the average ratio of indoor to outdoor fungi concentrations ranged from 0.35 to 2.01, which is regarded as too low to indicate any presence of indoor fungi sources. In regard to respirable fungi, the average concentrations were 100-2200 CFU m "3 in the living rooms, 18-3000 CFU m "3 in the bathrooms, 2452400 CFU m 3 in the bedrooms, and 0-2600 CFU m -3 in the kitchens. Aditionally, the average outdoor concentrations ranged from 70 to 3600 CFU m "3. It was found that respirable fungi constituted approximately 70%-85% of the total counts. The overall average with standard deviation and geometric mean concentrations of respirable fungi varied from 500 to 1500 CFU m "3, as shown in Fig. 2.
Microbiological indoor air quality in subtropical areas
235
3000
• May I I
[][] June May/June
2000 v
o
cD
1000
I.
o
Out
LR
Bedm
Kit
Bath
Sampling Locations
• May [] June [] May/June
2000
[.u o
o¢ J o
L)
,l:ioioFff/ i [ O |
. . . .
Out
I
LR
Bedm
Kit
Bath
Sampling Locations Fig. 1. The overall average with standard deviation (upper) and geometric mean (lower) of the total fungi concentrations in different sampling locations.
Regarding the relationship of culturable airborne fungi between outdoors and living rooms, the Pearson correlation coefficient was found to be 0.56 (Fig. 3). The indoor fungi concentrations are considered to be directly correlated with those observed outdoors. Table 1 shows the Pearson correlation coefficients calculated between the CFU m "3
values found in living rooms, bedrooms, kitchens, bathrooms, and outdoors. A high correlation coefficient was found (r>0.60; p<0.05) between the concentrations in living rooms and kitchens. A correlation coefficient of only 0.366 was observed between the concentrations in bath-rooms and outdoors.
236
C.-S. Li and Y.-M. Kuo
3000
2000 •
v
May
[] June
O
[] May/June
1000 {.} 0
0. Out
LR
Bedm
Kit
Bath
Sampling Locations
2000
1500 • 0
°¢-,
1000
May
[] June [] May/June
¢.3,
0
0
Out
LR
Bedm
Kit
Bath
Sampling Locations Fig. 2. The overall average with standard deviation (upper) and geometric mean (lower) of the respirable fungi concentrations in different sampling locations.
Concerning the fungi genus identifications, Aspergillus, PeniciUium, and Cladosporium are the health-related fungi, which were mainly isolated from both indoor and outdoor samples. The maximum airborne concentrations of Aspergillus, Penicillium, and Cladosporium in the six cases are shown in Fig. 4. Large variations were observed in the concentrations of Aspergillus, Penicillium, and Cladosporium. In
some conditions, the c o n c e n t r a t i o n s of Aspergillus, Penicillium, and Cladosporium could reach as high as 1500 CFff m "3. The prevalence of children's asthma in Taipei was 1.3% in 1974 and increased to 5.07% in 1985 (Hsieh and Shen 1988). Whether the high prevalent rate of children's asthma in Taipei correlates with the measured high c o n c e n t r a t i o n s of asthma-related fungi needs further studies.
Microbiological indoor air quality in subtropical areas
o
237
tO000
o
hi) .~.~ .,=.l
% E 100o Q
oe
r = 0.56
o o
100 lO0
I
I
I
I
i
I
t
I
•
,
.
1000
.
.
.
.
|
10000
Concentration (CFU/m 3) outdoors Fig. 3. The relationship between outdoor and indoor airborne fungi in six residences.
Table 1. Pearson correlation coefficients between the concentrations of CFU/m~(In-transformed)obtained in different sampling locations.
Living Room Bedroom Kitchen Bathroom
Outdoor
Living Room Bedroom
Kitchen
0.561 0.445 0.466 0.366
0.544 0.629 0.521
0.471
0.422 0.578
• Boldface type indicates a significant (P < 0.05) associationbetween the paried variables.
CONCLUSIONS
The field characterizations of indoor and outdoor fungi were evaluated in six residences in the Taipei area. The concentrations of indoor and outdoor fungi were observed to be higher than the level ACGIH suggested to be present from indoor bioaerosol sources. From the results of these field measurements, the high temperature and high relative humidity in Taiwan should play an important role in the observed high
fungi c o n c e n t r a t i o n s . In addition, the respirable f u n g i d o m i n a t e d and c o n s t i t u t e d 70%-85% of the total fungi numbers. The airborne Aspergillus, Penicillium, and Cladosporiumconcentrations indoors and outdoors could reach as high as 1500 CFU m "3. One-year field measurements of indoor and outdoor fungi are undertaken to evaluate the seasonal variations of microbiological indoor air quality in Taiwan.
C.-S. Li and Y.-M. Kuo
238
1500
1000
[] [] [] []
o C~ 0 0
500
Indoor, May Outdoor, May Indoor, June Outdoor, June
o
0 case 1
case 2
case 3
case 4
case 5
case 6
Sampling Locations 2000 1500 o
[] [] [] []
1000
0
o
500
Indoor, May Outdoor, May Indoor, June Outdoor, June
// i
/-1.
case 1
case 2
case 3
.
case 4
case 5
case 6
Sampling Locations 2000
1500
P, .= i
• [] [] []
1000
Indoor, May Outdoor, May Indoor, June Outdoor, June
500 0 case 1
case2
case3
case4
case5
case6
Sampling Locations Fig. 4. The m a x i m u m concentrations of Aspergiilus (upper), Peniciilium (middle), and Cladosporium (lower) in six residences.
Microbiological indoor air quality in subtropical areas
-This work was supported by the Taiwan National Science Council under Grant NSC 81-0421-B-002-609-Z and NSC 81-0421 -F-002-541-Z.
Acknowled&ment
REFERENCES ACGIH (American Conference of Governmental Industrial Hygiene). Bioaerosols: Rationale for monitoring airborne viable microorganisms in the office environment. Appl. Ind. Hyg. 4: R19-R23; 1986. Burge, H.A. Bioaerosols: prevalence and health effects in the indoor environment. L Allergy Clin. Immunol. 86:687-701; 1991. Chatigny, M.A.; Macher, J.M.; Burge, H.A.; Solomon, W.R. Sampling airborne microorganisms and aeroallergens. In: Air sampling instruments. Cincinnati, OH: ACGIH; 1986: 199-220. Flannigan, B.; McCabe, E.M.; McGarry, F.; Strachan, D.P. Wheeze in children: an investigation of the air spore in the home. In: Walkinshaw, D.S., ed. Proc. 5th int. conf. Indoor Air Quality and Climate, Vol. 4. Ottawa: Canada Mortgage and Housing Corporation; 1990: 27-32. Hsieh, K.H.; Shen, J.L Prevalence of children asthma in Taipei, Taiwan, and other Asian Pacific countries. J. Asthma 25: 73-82; 1988.
239
Macher, J.M.; Huang, F.Y.; Flores, M.A. A two-year study of microbiological indoor air quality in a new apartment. Arch. Environ. Health 46: 25-29; 1991. NRC (National Research Council). Indoor pollutants; Committee on Indoor Pollutants. Washington, DC: National Academy Press; 1981. Nevalinen, A. Pasanen, A.-L.; Nininen, M.; Reponen, T.; Kalliokoski, P.; Jantunen, M.J. The indoor air quality in Finnish homes with mold problems. Environ. Int. 17: 299-302; 1991. Pasanen, A.L.; Kalliokoski, O.; Pasanen, P.; Jantunen, M.J.; Nevalainen, A. Laboratory studies on the relationship between fungal growth and atmospheric temperature and humidity. Environ. Int. 17: 225-228; 1991. Reponen, S.L; Nevalainen, A.; Raunemaa, T. Bioaerosol and particle mass levels and ventilation in Finnish homes. Environ. Int. 15: 203-208; 1989. Reynolds, S.J.; Streifel, A.J.; McJilton, C.E. Elevated airborne concentrations of fungi in residential and office environments. Am. Ind. Hyg. Assoc. J. 51: 601-604; 1990. Su, H.J.; Burge, H.A. Examination of microbiological concnetrations and association with children respiratory health. In: Walkinshaw, D.S., ed. Proc. 5th int. conf. Indoor Air Quality and Climate, Vol. 4. Canada Mortgage and Housing Corporation; 1990: 21-26.
0160-4120/93 $6.00 +.00 Copyright 01993 Pergamon Press Ltd.
MICROBIOLOGICAL INDOOR AIR QUALITY IN SUBTROPICAL AREAS Chih-Shan Li and Yu-Mei Kuo Division of Environmental Health Science, Institute of Public Health, College of Medicine, National Taiwan University, Taipei, Taiwan, R.O.C.
E19212-208 M (Received 17 December 1992; accepted 13 February 1993)
In Taiwan, a subtropical country, bioaerosols are regarded to be quick to grow, because of high relative humidity and high temperature all year around. Field investigations of microbiological indoor air quality were performed in six apartments in the Taipei area. Two-stage Andersen viable impuctors were used to determine the concentration, genus, and respirable fraction of fungi indoors and outdoors. The fungi characteristics in living rooms, bedrooms, kitchens, bathrooms, and outdoors were compared. The concentrations of indoor and outdoor fungi in different locutions of the six apartments were found to vary widely. The geomentric mean concentrations of indoor and outdoor fungi were higher than I000 CFU m "3. Moreover, more than 80% of indoor and outdoor fungi were observed to be respirable. In addition, the ratios of indoor to outdoor fungi concentrations were too low to indicate the presence of any indoor fungi sources. In some homes, the concentrations of the asthma-related fungi genus, Aspergillus, Penicillium, and Cladosporium, were found to exceed 500 CFU m -3.
INTRODUCTION
al. 1990). Currently, it is suggested by the American Conference of Governmental Industrial Hygiene (ACGIH 1986) that bioaerosol concentrations higher than 500 CFU m "3 be considered as a sign of the presence of a building-related air pollution source. It was pointed out from bioaerosol investigations in Finnish homes (Reponen et al. 1989; Nevalinen et al. 1991), that high concentrations of airborne fungal spores and bacterias were related with health complaints from the residents. In addition, the relationship between the microbiological concentrations and children's respiratory health problems was investigated during summer and winter seasons in 150 homes ( S u e t al. 1990). It was found that hay fever
In recent years, indoor air quality has become an important issue, because of the occurrance of the "sick building syndrom" and the factthat most people spend more than 80% of their time indoors (NRC 1981). Indoor bioaerosols have been well recognized as the major cause of symptoms in reports of, for example, absences in classrooms and officesor lower productivity in hospitals and occupational environments (Burge 1991; Chatigny et al. 1989). Moreover, it was found that the fungi concentrations inside the buildings significantlyexceeded the outdoor levels, being higher than 500 C F U m "3 in six residences and offices in Minneapolis (Reynolds et 233
234
has a significant correlation with indoor fungi, such as Cladosporium, Epicoccum, and Yeast. Furthermore, children's respiratory symptoms and wheezing and/or asthma complaints of school-age children have shown a statistically significant association with indoor Aspergillus concentrations. From the previous reports mentioned above, many of the building-related illnesses had been identified, and bioaerosols were found to be responsible for the observed health effects. Taiwan, a subtropical country, has warm weather (20-37°C) and high relative humidity (65%-90%) all year round. From an investigation of the influence of temperature and relative humidity on fungal growth (Pasanen et al. 1991), it was found that temperature of 21-30°C and relative humidity of 75%-92% could induce fungal germination and growth more quickly. Therefore, it is considered that bioaerosols are much easier to grow in subtropical areas. It is necessary to evaluate whether there is a microbiological indoor air quality problem in Taiwan. In this investigation, field characterizations of indoor and outdoor fungi in six Taipei apartments were conducted. Two-stage Andersen viable impactors were used to determine concentrations and the genus of nonrespirable and respirable fungi in living rooms, bedrooms, kitchens, bathrooms, and outdoor environments. Therefore, it was possible to evaluate the fungi characteristics in different indoor locations and outdoors. MATERIALS AND METHODS
The field evaluation of microbiological indoor air quality in six Taipei apartments was performed in May and June of 1992. Fungi were sampled with two-stage Andersen viable impactors on malt extract agar (ACGIH 1986). These samplers can classify fungi into nonrespirable (>4.7 lxm) and respirable (<4.7 Ixm) fractions at a constant flowrate of 28.4 L/min. The sampling locations included living rooms, bathrooms, bedrooms, kitchens, and outdoor areas of the six homes with duplicate measurements in each place. During the field measurements, the sampling time ranged from 20 sec to 1 rain. The temperature and relative humidity were recorded. The samplers for indoor and outdoor measurements were located 1.2m to 1.5 m above the floor to simulate the human breathing zone. The plates were incubated at 250C for four to six days to measure the fungi. The biological m e a s u r e m e n t s w e r e c l a s s i f i e d i n t o
Alternaria, Aureobasidiura, Cladosporium, Curvularia, Drechslera, Asperillus, Penicillium, Paecilomyces, Fusarium, Trichoderma, Scopulariopsis, Acremonium,
C.-S. Li and Y.-M. Kuo
Geotrichum, Monilia,Rizopus, Mucor, Syncephalastrum, Yeast, and others; or they were not classified. Original concentrations of airborne fungi measured in different locations of the six residences (in CFU m "3) were transformed by natural logarithm to approximate normality in the analysis. A SAS statistical p a c k a g e was utilized for s t a t i s t i c a l analysis. RESULTS AND DISCUSSIONS
The field investigation of indoor and outdoor fungi was conducted in six apartments in Tapei for evaluating whether bioaerosols are an indoor air quality problem in Taiwan. During the field measurements, temperature and relative humidity were found to be in the range of 21-3 I°C and 70%-85%, respectively. The concentrations of indoor and outdoor fungi in different locations of six apartments were observed to vary widely. The average indoor fungi concentrations were in the range of 140-3200 CFU m -3 in the living room, 420-1800 CFU m "3 in the bathrooms, 4382870 CFU m -3 in the bedrooms, and 508-3000 CFU m -3 in the kitchens. In addition, the average outdoor concentrations ranged from 400 CFU m "3 to 4200 CFU m'3. It was found that indoor fungi concentrations in Tapei were significantly higher than those observed in San Francisco (Macher et al. 1991) and Edinburgh (Flannigan et al. 1990), as well as comparable to those found in Finnish moldy homes (Reponen et al. 1989; Nevalinen et al. 1991). Furthermore, the observed maximum concentrations of indoor and outdoor fungi_in every case could be as high as 3500 CFU m "3" The overall average with standard deviation and geometric mean of the total fungi concentrations were found to exceed 1000 CFU m"3 in each sampling location of the six homes (as shown in Fig. 1). The fungi concentrations measured in June were found to be much higher than those observed in May. Moreover, the average ratio of indoor to outdoor fungi concentrations ranged from 0.35 to 2.01, which is regarded as too low to indicate any presence of indoor fungi sources. In regard to respirable fungi, the average concentrations were 100-2200 CFU m "3 in the living rooms, 18-3000 CFU m "3 in the bathrooms, 2452400 CFU m 3 in the bedrooms, and 0-2600 CFU m -3 in the kitchens. Aditionally, the average outdoor concentrations ranged from 70 to 3600 CFU m "3. It was found that respirable fungi constituted approximately 70%-85% of the total counts. The overall average with standard deviation and geometric mean concentrations of respirable fungi varied from 500 to 1500 CFU m "3, as shown in Fig. 2.
Microbiological indoor air quality in subtropical areas
235
3000
• May I I
[][] June May/June
2000 v
o
cD
1000
I.
o
Out
LR
Bedm
Kit
Bath
Sampling Locations
• May [] June [] May/June
2000
[.u o
o¢ J o
L)
,l:ioioFff/ i [ O |
. . . .
Out
I
LR
Bedm
Kit
Bath
Sampling Locations Fig. 1. The overall average with standard deviation (upper) and geometric mean (lower) of the total fungi concentrations in different sampling locations.
Regarding the relationship of culturable airborne fungi between outdoors and living rooms, the Pearson correlation coefficient was found to be 0.56 (Fig. 3). The indoor fungi concentrations are considered to be directly correlated with those observed outdoors. Table 1 shows the Pearson correlation coefficients calculated between the CFU m "3
values found in living rooms, bedrooms, kitchens, bathrooms, and outdoors. A high correlation coefficient was found (r>0.60; p<0.05) between the concentrations in living rooms and kitchens. A correlation coefficient of only 0.366 was observed between the concentrations in bath-rooms and outdoors.
236
C.-S. Li and Y.-M. Kuo
3000
2000 •
v
May
[] June
O
[] May/June
1000 {.} 0
0. Out
LR
Bedm
Kit
Bath
Sampling Locations
2000
1500 • 0
°¢-,
1000
May
[] June [] May/June
¢.3,
0
0
Out
LR
Bedm
Kit
Bath
Sampling Locations Fig. 2. The overall average with standard deviation (upper) and geometric mean (lower) of the respirable fungi concentrations in different sampling locations.
Concerning the fungi genus identifications, Aspergillus, PeniciUium, and Cladosporium are the health-related fungi, which were mainly isolated from both indoor and outdoor samples. The maximum airborne concentrations of Aspergillus, Penicillium, and Cladosporium in the six cases are shown in Fig. 4. Large variations were observed in the concentrations of Aspergillus, Penicillium, and Cladosporium. In
some conditions, the c o n c e n t r a t i o n s of Aspergillus, Penicillium, and Cladosporium could reach as high as 1500 CFff m "3. The prevalence of children's asthma in Taipei was 1.3% in 1974 and increased to 5.07% in 1985 (Hsieh and Shen 1988). Whether the high prevalent rate of children's asthma in Taipei correlates with the measured high c o n c e n t r a t i o n s of asthma-related fungi needs further studies.
Microbiological indoor air quality in subtropical areas
o
237
tO000
o
hi) .~.~ .,=.l
% E 100o Q
oe
r = 0.56
o o
100 lO0
I
I
I
I
i
I
t
I
•
,
.
1000
.
.
.
.
|
10000
Concentration (CFU/m 3) outdoors Fig. 3. The relationship between outdoor and indoor airborne fungi in six residences.
Table 1. Pearson correlation coefficients between the concentrations of CFU/m~(In-transformed)obtained in different sampling locations.
Living Room Bedroom Kitchen Bathroom
Outdoor
Living Room Bedroom
Kitchen
0.561 0.445 0.466 0.366
0.544 0.629 0.521
0.471
0.422 0.578
• Boldface type indicates a significant (P < 0.05) associationbetween the paried variables.
CONCLUSIONS
The field characterizations of indoor and outdoor fungi were evaluated in six residences in the Taipei area. The concentrations of indoor and outdoor fungi were observed to be higher than the level ACGIH suggested to be present from indoor bioaerosol sources. From the results of these field measurements, the high temperature and high relative humidity in Taiwan should play an important role in the observed high
fungi c o n c e n t r a t i o n s . In addition, the respirable f u n g i d o m i n a t e d and c o n s t i t u t e d 70%-85% of the total fungi numbers. The airborne Aspergillus, Penicillium, and Cladosporiumconcentrations indoors and outdoors could reach as high as 1500 CFU m "3. One-year field measurements of indoor and outdoor fungi are undertaken to evaluate the seasonal variations of microbiological indoor air quality in Taiwan.
C.-S. Li and Y.-M. Kuo
238
1500
1000
[] [] [] []
o C~ 0 0
500
Indoor, May Outdoor, May Indoor, June Outdoor, June
o
0 case 1
case 2
case 3
case 4
case 5
case 6
Sampling Locations 2000 1500 o
[] [] [] []
1000
0
o
500
Indoor, May Outdoor, May Indoor, June Outdoor, June
// i
/-1.
case 1
case 2
case 3
.
case 4
case 5
case 6
Sampling Locations 2000
1500
P, .= i
• [] [] []
1000
Indoor, May Outdoor, May Indoor, June Outdoor, June
500 0 case 1
case2
case3
case4
case5
case6
Sampling Locations Fig. 4. The m a x i m u m concentrations of Aspergiilus (upper), Peniciilium (middle), and Cladosporium (lower) in six residences.
Microbiological indoor air quality in subtropical areas
-This work was supported by the Taiwan National Science Council under Grant NSC 81-0421-B-002-609-Z and NSC 81-0421 -F-002-541-Z.
Acknowled&ment
REFERENCES ACGIH (American Conference of Governmental Industrial Hygiene). Bioaerosols: Rationale for monitoring airborne viable microorganisms in the office environment. Appl. Ind. Hyg. 4: R19-R23; 1986. Burge, H.A. Bioaerosols: prevalence and health effects in the indoor environment. L Allergy Clin. Immunol. 86:687-701; 1991. Chatigny, M.A.; Macher, J.M.; Burge, H.A.; Solomon, W.R. Sampling airborne microorganisms and aeroallergens. In: Air sampling instruments. Cincinnati, OH: ACGIH; 1986: 199-220. Flannigan, B.; McCabe, E.M.; McGarry, F.; Strachan, D.P. Wheeze in children: an investigation of the air spore in the home. In: Walkinshaw, D.S., ed. Proc. 5th int. conf. Indoor Air Quality and Climate, Vol. 4. Ottawa: Canada Mortgage and Housing Corporation; 1990: 27-32. Hsieh, K.H.; Shen, J.L Prevalence of children asthma in Taipei, Taiwan, and other Asian Pacific countries. J. Asthma 25: 73-82; 1988.
239
Macher, J.M.; Huang, F.Y.; Flores, M.A. A two-year study of microbiological indoor air quality in a new apartment. Arch. Environ. Health 46: 25-29; 1991. NRC (National Research Council). Indoor pollutants; Committee on Indoor Pollutants. Washington, DC: National Academy Press; 1981. Nevalinen, A. Pasanen, A.-L.; Nininen, M.; Reponen, T.; Kalliokoski, P.; Jantunen, M.J. The indoor air quality in Finnish homes with mold problems. Environ. Int. 17: 299-302; 1991. Pasanen, A.L.; Kalliokoski, O.; Pasanen, P.; Jantunen, M.J.; Nevalainen, A. Laboratory studies on the relationship between fungal growth and atmospheric temperature and humidity. Environ. Int. 17: 225-228; 1991. Reponen, S.L; Nevalainen, A.; Raunemaa, T. Bioaerosol and particle mass levels and ventilation in Finnish homes. Environ. Int. 15: 203-208; 1989. Reynolds, S.J.; Streifel, A.J.; McJilton, C.E. Elevated airborne concentrations of fungi in residential and office environments. Am. Ind. Hyg. Assoc. J. 51: 601-604; 1990. Su, H.J.; Burge, H.A. Examination of microbiological concnetrations and association with children respiratory health. In: Walkinshaw, D.S., ed. Proc. 5th int. conf. Indoor Air Quality and Climate, Vol. 4. Canada Mortgage and Housing Corporation; 1990: 21-26.