Risks of unsatisfactory airborne bacteria level in air-conditioned offices of subtropical climates

Mui, Kwok Wai; Wong, Ling Tim; Hui, P. S.

doi:10.1016/j.buildenv.2007.01.012

Cited by 29 publications

(23 citation statements)

References 13 publications

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“…Similar studies were conducted in four office buildings in Warsaw, Poland, and the results showed that the concentration of bacteria in the office rooms air was 500 CFU m −3 (Gołofit-Szymczak and Górny 2010). Results obtained in office buildings in Gliwice are analogous to the data found in studies carried out in air-conditioned office buildings in Hong Kong, where the mean concentration of airborne bacteria w a s 5 8 0 C F U m − 3 , w i t h a m a x i m u m v a l u e o f 2300 CFU m −3 (Mui et al 2008). A significantly lower concentration level of bacterial aerosol was found in Turin, Italy, during the summer, where the average concentration of bacterial aerosol was 198 CFU m −3 and the maximum concentration was 368 CFU m −3 (Bonetta et al 2010).…”

Section: Viable-culturable Count (Vcc) Of Bacterial Aerosolsupporting

confidence: 79%

Microbiological indoor air quality in an office building in Gliwice, Poland: analysis of the case study

Brągoszewska

Biedroń

Kozielska

et al. 2018

Air Qual Atmos Health

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Bioaerosols play a significant role in indoor air quality (IAQ) as they can be the cause of several health problems, including acute allergies and infectious diseases. This study aimed to characterize and compare the microbial air quality of air-conditioned (AC) and naturally ventilated (NV) office rooms in the Upper Silesia region of Poland. The bacterial samples were collected during the late spring season. Culturable bacteria were deposited on the nutrient media on Petri dishes to investigate the viable-culturable count (VCC) of bacteria and bacterial community structure using a Biolog GEN III system. In total, 12 species of bacteria were identified, with the most isolated Macrococcus equipercicus, Micrococcus luteus D, Staphylococcus xylosus (indoor), and Bacillus species (outdoor). The indoor mean concentrations of bacterial aerosol ranged from 10 2 to 10 3 CFU m −3 , below Polish proposals for threshold limit standards in office buildings. The indoor-to-outdoor (I/O) ratios indicated that studied air pollutants in the office rooms originated from the indoor air. These results, together with community composition of bacteria, indicate that most of the bacteria present in the studied office building were relatively fresh and of human origin. Multi-antibiotic resistance (MAR) tests showed that the most antibiotic-resistant features were present in Macrococcus species. The office building exposure dose (OBED) and mass median aerodynamic diameter (MMAD) of bacteria aerosol were estimated. The highest value of OBED over the study period was obtained for staff working in offices with natural ventilation (141 CFU kg −1 ), in contrast to the value for staff working in offices equipped with air conditioning (about 100 CFU kg −1 ). The MMAD of viable airborne bacteria was higher in AC offices (2.4 μm) than in NV offices (2.2 μm).

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Section: Viable-culturable Count (Vcc) Of Bacterial Aerosolsupporting

confidence: 79%

Microbiological indoor air quality in an office building in Gliwice, Poland: analysis of the case study

Brągoszewska

Biedroń

Kozielska

et al. 2018

Air Qual Atmos Health

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“…Staphylococcus and Micrococcus were dominant among the 11 genera identified in that study. Additionally, Grampositive cocci, including Staphylococcus and Micrococcus, have been reported to be dominant in the indoor air in schools (Aydogdu et al 2005;Bartlett et al 2004), homes (Pastuszka et al 2000), hospitals (Sarica et al 2002), offices (Mui et al 2008), and public buildings (Kim and Kim 2007). The bacterial genera isolated predominantly in our study are from both environmental and human sources.…”

Section: Discussionmentioning

confidence: 90%

Indoor and outdoor airborne bacteria in child day-care centers in Edirne City (Turkey), seasonal distribution and influence of meteorological factors

Aydoğdu

Asan

Otkun

2009

Environ Monit Assess

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This paper presents information about airborne mesophilic bacteria in the indoor and outdoor air of child day-care centers (CDCCs) in the city of Edirne, Turkey. Air samples were collected using the Petri plate gravitational settling method from the indoor and outdoor air of CDCCs. Counts of airborne bacteria were measured as colony forming units (CFU) collected by gravity onto Brain Heart Infusion Agar plates (with 5% sheep blood). Samples were taken monthly over a period of 12 months between January and December 2004. A total of 3,120 bacteria colonies were counted on 192 Petri plates. Four groups of culturable bacteria were identified: gram-positive cocci, gram-positive bacilli, endospore-forming gram-positive bacilli, and gram-negative bacteria. Airborne gram-positive bacteria were the most abundant at more than 95% of the measured population. While gram-positive cocci were more common in indoor environments, gram-positive bacilli were more dominant in outdoor air. Bacteria commonly isolated from CDCCs were identified at a genus level. Staphylococcus (39.16%), Bacillus (18.46%), Corynebacterium (16.25%), and Micrococcus (7.21%) were dominant among the genera identified in the present study. The dominant genera identified in the day-care centers were Staphylococcus, Micrococcus, and Corynebacterium for indoor air and Bacillus, Corynebacterium, and Staphylococcus for outdoor air. Staphylococcus, Streptococcus, Bacillus, and Corynebacterium genera were found in samples from every month. Bacterial colony counts were compared by sampling location (indoors and outdoors), seasons, and meteorological factors. We found negative correlations between the monthly total outdoor bacterial counts and the sampling day's average relative humidity and average rainfall, and the monthly average rainfall. Fluctuations in bacterial counts in different seasons were observed.

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“…Staphylococcus (50%), Micrococcus (15-20%), Corynebacterium (5-25%), and Bacillus (5-15%) were detected as the popular bacterial genera in Korea hospital (Kim et al, 2010). Moreover, Staphylococcus and Micrococcus were also considered as the prevalent bacteria in the air in other indoor environments such as in schools (Aydogdu et al, 2005), family homes (Pastuszka et al, 2000), university hospitals (Sarica et al, 2002), air-conditioned offices (Mui et al, 2008), public buildings (Kim and Kim, 2007), libraries and archives (Karbowska-Berent et al, 2011). All of these dominant airborne bacteria are originated from nature environment and center as human beings.…”

Section: Discussionmentioning

confidence: 99%

Characteristic and Concentration Distribution of Culturable Airborne Bacteria in Residential Environments in Beijing, China

Fang

Gong

Ouyang

et al. 2014

Aerosol Air Qual. Res.

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The present investigation was conducted to assess the culturable concentration and distribution characteristics of airborne bacteria in 31 homes with children aged from 1 to 10 years in Beijing, China. The results showed that the concentration of culturable airborne bacteria in these homes ranged from 47 colony forming units (CFU)/m 3 to 12341 CFU/m 3 , with a mean and a median of 1821 and 877 CFU/m 3 , respectively. A total of 632 bacterial isolates from the air in homes in different regions and different seasons were identified and distributed across 43 genera and 136 species of bacteria. Micrococcus (26.74%), Bacillus (14.56%), Kocuria (12.66%), and Staphylococcus (12.03%) were determined as the most common culturable airborne bacteria, and the dominant bacterial species were Micrococcus luteus (14.56%), Kocuria roseus (8.39%), Bacillus megaterium (4.75%), Staphylococcus cohnii (3.63%), and Micrococcus lylae (3.01%). Data analysis revealed that bacterial concentrations in homes with a male child were significantly higher than those with a female child (**P < 0.01), and a negative correlation was found between bacterial concentration and living area per person in the homes (**P < 0.01). Additionally, the mean bacterial concentration was highest in Spring, followed by Summer and Autumn, and lowest in Winter (**P < 0.01) in homes with child. The results provide an exposure database of airborne bacteria in family homes in Beijing, and suggest that the sex of children and living area per person in homes have a significant influence on the bacterial concentration in the air.

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Risks of unsatisfactory airborne bacteria level in air-conditioned offices of subtropical climates

Cited by 29 publications

References 13 publications

Microbiological indoor air quality in an office building in Gliwice, Poland: analysis of the case study

Microbiological indoor air quality in an office building in Gliwice, Poland: analysis of the case study

Indoor and outdoor airborne bacteria in child day-care centers in Edirne City (Turkey), seasonal distribution and influence of meteorological factors

Characteristic and Concentration Distribution of Culturable Airborne Bacteria in Residential Environments in Beijing, China

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