• 설비공학논문집
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• 제21권10호
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• pp.583-589
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• 2009

Activated carbon has long been used in purification processes for indoor air quality. However, the bioaerosol removal by activated carbon is not often sufficient to be used in an air control devise. In order to overcome these problems, silver nano-particles have been proposed as an antibacterial agent on the surface of activated carbon. Silver or silver ions have been known for antimicrobial activities. In this study, bioaerosol generated by using an Escherichia coli culture was introduced to a lab-scale column packed with activated carbon (AC) and silver nano-particles attached to activated carbon (Ag-AC). E. coli was almost completely removed in the Ag-AC column, whereas bioaerosol penetrated through the AC column. To determine the antibacterial effect of different filter materials in a full-scale air-handling system, another experiment was conducted using a wind tunnel equipped with a heat exchanger and three filter materials including commercial fabric, AC and Ag-AC. It was found that E. coli proliferated on the surface of the heat exchanger after 5 days, which dramatically increased bioaerosol counts in the effluent air stream. The fabric filter could not control the increased bioaerosol and most of the E. coli penetrated the filter. The bacterial removal efficiency was found to be approximately 45% in the AC filter, while the antibacterial efficiency increased to 70% using the Ag-AC filter. Consequently, the Ag-AC filter can be an effective method to control bioaerosol and improve indoor air quality.

• 한국환경보건학회지
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• 제42권2호
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• pp.133-140
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• 2016

Objectives: A pilot study was undertaken to assess the bioaerosol levels in restaurants and determine the effects of variations in temperature, relative humidity, and air movement on these levels. It focused on the differences between kitchens and dining areas, as well as between summer and winter. Methods: A field survey was performed in six restaurants. An Anderson type air sampler was used for sampling bioaerosols, such as total suspended bacteria (TSB), Gram-negative bacteria (GNB), Gram positive bacteria (GPB), opportunistic bacteria (OP), Staphylococcus spp., and total suspended fungi (TSF). Results: The average levels of TSB were $1{\times}10^2CFU/m^3$ and of TSF they were $1{\times}10^0{\sim}10^1CFU/m^3$. The kitchens had higher bioaerosol levels compared to dining areas, and summer showed much higher levels than winter. The concentration of OP in summer was more than six-fold that of winter. S. aureus was detected both in kitchens and dining areas, even in winter. The main effect of air movement on TSB levels was significant (p<0.05), as was air temperature, relative humidity and air movement on TSF levels (p<0.05). Conclusion: There was a wide variation in bioaerosol levels among different restaurants. The results indicate that cooking foods may be a key factor affecting bioaerosol levels. The effects of air temperature and relative humidity reveal that bioaerosol levels may vary according to the season. The observation of pathogenic bacteria suggests that the hygiene management of establishments should be improved. Future research is needed to characterize the relation between bioaerosol levels and the occupant density of the dining area.

• 한국환경보건학회지
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• 제40권4호
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• pp.304-312
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• 2014

Objectives: This study was performed to examine bioaerosols in indoor air in public restrooms, as well as to assess the effects of air temperature and relative humidity on bioaerosol levels. Methods: A cross-sectional survey was performed in ten male and ten female restrooms. An air sampler (Anderson type) was used for sampling total suspended bacteria (TSB), Gram-negative bacteria (GNB), Gram-positive bacteria (GPB), opportunistic bacteria (OP), Staphylococcus spp., and total suspended fungi (TSF). Results: The levels of TSB were $10-10^2CFU/m^3$ and TSF $10-10^2CFU/m^3$, respectively. The GNB level was $0-10CFU/m^3$, and GPB and OP levels were $10-10^2CFU/m^3$. Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were detected in 90% of the restrooms. The GPB level was higher in the female restrooms than in the male restrooms (p < 0.05). TSB, GNB, and TSF showed higher levels in restrooms in buildings over 30 years old (p < 0.01). The main effect of air temperature or relative humidity and interaction effect of the two factors on the TSB level were significant (p < 0.05), while the effect of relative humidity on the TSF level was significant (p < 0.001). Conclusions: These results indicate that there is a wide variation in the bioaerosol levels among different restrooms. The observed differences in bioaerosol levels reflect different building histories. The effects of air temperature and/or relative humidity reveal that bioaerosol levels may vary according to season or time of day. Future research is needed to further characterize the relation between the bioaerosol levels and surface contamination in restrooms.

• 한국환경보건학회지
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• 제38권6호
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• pp.503-509
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• 2012

Objectives: This study was performed in order to evaluate the generation characteristics of airborne bacteria and fungi while operating a household humidifier, in consideration of user habits. Methods: Microbial samples were collected in a closed chamber with a total volume of 2.76 $m^3$, in which a humidifier was operated according to experimental strategies. A cultivation method based on the viable counts of mesophilic heterotrophic bacteria and fungi was performed. Experimental strategies were divided into three classes: the type of water in the water reservoir (tap water, cooled boiled water); the frequency of filling the reservoir (refill every day, no refill); and the sterilization method (sterilization function mode, humidifier disinfectants). Results: Significant increases in the concentration of airborne bacteria were observed while the humidifier was in operation. The concentration had increased to 2,407 $CFU/m^3$ by 120 hours when tap water filled the reservoir without any application of sterilization, while for cooled boiled water, it was merely 393 $CFU/m^3$ at a similar time point. Usages of disinfectant in the water tank were more effective in decreasing bioaerosol generation compared to sterilization function mode operation. Generation characteristics of airborne fungi were similar to those of bacteria, but the levels were not significant in all experiments. Calculated exposure factor can be used as an indicator to compare biorisk exposure. Conclusion: This study identified the potential for bioaerosol generation in indoor environments while operating a household humidifier. User practices were critical in the generation of bioaerosol, or more specifically, airborne bacteria. Proper usage of a humidifier ensures that any biorisks resulting from generated bioaerosol can be prevented.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 Proceedings of KSEH.Minamata Forum
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• pp.83-84
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• 2005

This research was performed to measure the concentration distribution of Bioaero sol in apartment houses in the region of Chungnam (Chunan, Asan) for 1 month, December, 2004. The results are as follows.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.381-382
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• 2001

Bioaerosol은 인공적으로 생성되거나, 혹은 자연적으로 발생하는 생물학적 기원(biological origin)을 가진 물질로 정의한다. 실내공기 중에서 이러한 Bioaerosol 발생의 중요한 원인으로는 실외에서 유입되는 경우와 건물의 HVAC 시스템에 의한 경우, 실내에 거주하고 있는 사람이나 동물에 의한 경우가 대표적이다. 특히 이 세 가지 오염원 중에서 실내 거주자와 동물이 가장 중요한 역할을 하는 것으로 보고되고 있다(Pastuszka 등, 2000). (중략)

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2004년도 가을 학술발표회지 제13권(제2호)
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• pp.39-40
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• 2004

초등학교에서의 실내공기 중 미생물 농도를 측정하여 본 결과 수업시간에 비하여 쉬는 시간에 아이들의 활동도에 따른 bacteria의 농도가 2.07배 증가하였고 유의성이 있는 것으로 나타났다. 에어컨을 가동 후 15분에서 미생물 농도가 최대가 되었으며, 이때의 농도가 2시간동안 가동하였을 때의 농도에 비해 12.29배 높게 나타났다. 이러한 에어컨 오염은 에어컨 내부 오염원에 의한 원인인 것으로 사료된다.

• 공기청정기술
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• 제15권3호통권58호
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• pp.1-12
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• 2002

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.709-717
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• 2015

Airborne bacteria from hog farms may have detrimental impacts on human health, particularly in terms of antibiotic resistance and pathogen zoonosis. Despite human health risks, very little is known about the composition and diversity of airborne bacteria from hog farms and hog-related spray fields. We used pyrosequencing analysis of 16S rRNA genes to compare airborne bacterial communities in a North Carolina hog farm and lagoon spray field. In addition, we isolated and identified antibiotic-resistant bacteria from both air samples. Based on 16S rRNA gene pyrosequence analysis, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla in airborne bacterial communities from both hog farm and spray field sites. Within the Firmicutes genera, Clostridium spp. were more abundant in the hog farm, whereas Staphylococcus spp. were higher in the spray field. The presence of opportunitic pathogens, including several Staphylococcus species and Propionibacterium acnes, was detected in both bioaerosol communities based on phylogenetic analysis. The isolation and identification of antibiotic-resistant bacteria from air samples also showed similar results with dominance of Actinobacteria and Proteobacteria in both hog farm and spray field air. Thus, the existence of opportunistic pathogens and antibiotic resistant bacteria in airborne communities evidences potential health risks to farmers and other residents from swine bioaerosol exposure.

• 한국환경과학회지
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• 제13권3호
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• pp.215-222
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• 2004

This study was conducted to evaluate the characterization of airborne bioaerosol in public facilities in Seoul. A total of 17 public facilities were investigated from December, 2002 to February, 2003. As results of the survey, the mean concentrations of bacteria and fungi in indoor air of public facilities were $378.08\pm296.33$ CFU/㎥ by RCS and $106.38\pm171.63$ CFU/㎥ and $347.46\pm335.32$ CFU/㎥ and $95.23\pm62.61$ CFU/㎥, by Six-stage cascade air sampler respectively. The mean concentrations of bacteria in indoor air (by ventilation method) were $517.14\pm343.93$ CFU/㎥ of natural ventilation and $215,83\pm100.71$ CFU/㎥ of mechanical ventilation. The mean concentrations of fungi in indoor air (by ventilation method) were $83.14\pm79.16$ CFU/㎥ of natural ventilation and $133.50\pm248.07$ CFU/㎥ of mechanical ventilation. The mean concentrations of bacteria in indoor air were 449.44 CFU/㎥ for the ground and $217.50\pm103.68$ CFU/㎥ for the underground. The mean concentrations of fungi in indoor air were $63.89\pm77.66$ CFU/㎥ for the ground and $202.00\pm290.08$ CFU/㎥ for the underground.