민감 계층 이용시설 내 실외 주변 환경 특성에 따른 부유세균 종분포 특성

조은민,이정섭,조용민,이철민 한국냄새환경학회 2020 실내환경 및 냄새 학회지 Vol.19 No.4

This study examines the effects of surrounding outdoor environmental characteristics in multi-use public facilities that are used by the susceptible population, on the concentration and distribution of indoor airborne bacteria. For this study, areas were divided into ‘factory area,’ ‘city area,’ and ‘forest area.’ The research was conducted from October 2017 to April 2018, and the selected target facilities were daycare centers, hospitals, postpartum care centers, and nursing homes for the elderly. In order to measure airborne bacteria, indoor air samples were collected using a six-stage viable particulate cascade impactor, and airborne bacteria samples were collected using MCE (Mixed cellulose esters) filters. Moreover, the outdoor airborne bacteria concentration was also measured to determine the concentration ratio (I/O ratio) of the total indoor airborne bacteria and total outdoor airborne bacteria concentrations. The results showed that the total outdoor airborne bacteria concentration was highest in the city area, with 74.2 ± 60.0 CFU/m3, and the lowest in the factory area, with 45.9 ± 35.8 CFU/m3. Furthermore, the distribution of the total outdoor airborne bacteria concentrations significantly differed across each surrounding environment (p < 0.05). On the other hand, no statistically significant difference in total indoor airborne bacteria concentrations, according to surrounding environments, was observed (p > 0.05). These findings suggest that the concentration of outdoor airborne bacteria differs across surrounding environments, unlike that of the indoor airborne bacteria.

경기북부지역 어린이집 부유미생물 발생과 실내공기와의 상관관계 분석

손해준,이강혁,정연훈,김진길,임윤정,유한조,최인태,윤수현,최형주,김종수 한국냄새환경학회 2021 실내환경 및 냄새 학회지 Vol.20 No.3

This study was conducted to help manage total floating bacteria and fungi in the indoor air by studying the characteristics of total floating bacteria and fungi according to the indoor CO2 concentration of daycare centers. The sampling and analysis of samples was based on the indoor air quality process test method, and the result analysis was conducted using the SPSS statistical program to perform correlation and regression analysis. Correlation and regression results show that CO2 and total airborne bacteria showed positive relationships, but airborne mold did not show relevance. In addition, in order to identify factors affecting airborne mold, correlation analysis and regression analysis were performed regarding total airborne bacteria, PM10, PM2.5, HCHO, outdoor mold, I/O ratio, indoor temperature/ humidity, area per classroom and volume. The results showed that the factors affecting airborne mold were I/O ratio, outdoor airborne mold, and total airborne bacteria. Research results show that CO2 and total airborne bacteria can be reduced and controlled by natural ventilation, and in the case of airborne mold, mechanical forced ventilation such as hoods will be necessary due to the introduction of outdoor airborne mold. In addition, it is necessary to consider I/O ratio criteria in order to confirm effective indoor mold contamination, taking into account the effect of outdoor mold inflow.

Microorganism-ionizing respirator with reduced breathing resistance suitable for removing airborne bacteria

Park, Miri,Son, Ahjeong,Chua, Beelee Elsevier 2018 Sensors and actuators. B, Chemical Vol.276 No.-

<P><B>Abstract</B></P> <P>In this paper, we have demonstrated the feasibility of using microorganism-ionizing respirators with reduced breathing resistance to remove airborne bacteria. Using a miniaturized corona ionizer and two pairs of separator electrodes, airborne bacteria were ionized and removed from the airflow. Two microorganism-ionizing respirator designs were experimentally evaluated with flow rates ranging from ∼10 to 20 L/min and yielded airborne bacterial removal efficiencies of ∼75%–100%. Further, they were in close agreement with the analytical airborne particle removal efficiencies, at a similar range of flow rates. These flow rates also correspond to the breathing rates of standing and walking adults. More importantly, the breathing resistance could be reduced by more than 50% for flow rates of ∼200 L/min. Using manganese (IV) oxide coated mesh, the ozone concentration in the air outflow was reduced to less than 0.1 ppm, at a flow rate of ∼20 L/min, thus enabling safe use. The power consumption was less than 1 W.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We demonstrated the ability of microorganisms ionizing respirator to remove airborne bacteria. </LI> <LI> It uses miniaturized corona ionizer and separator electrodes. </LI> <LI> Airborne bacteria was electrically charged and removed from air flow. </LI> <LI> Its breathing resistance was less than that of commercial N95 respirator. </LI> <LI> Contributes to the comfort and ease of breathing of the wearer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

실내공기 부유세균의 전국 현황 및 특성 분석

박용성,권순현,이준환,이효선,박송이,기선호,윤원석 한국냄새환경학회 2022 실내환경 및 냄새 학회지 Vol.21 No.3

Distribution of airborne bacteria in the entire regions of South Korea was investigated and analyzed by region and type of multi-use facilities. At first, 10 public facilities were selected including general restaurant, retail store, public transport, retail market, apartment house, underground parking lot, financial institution, business facility, educational institution, and public toilet, which are located at the regions such as Seoul, Busan, Daejeon, Gwangju, Gyeonggi, Jeju, and Gangwon. The regional distribution of the floating bacteria was identified that Micrococcus sp. was highly prevalent in Seoul (21.5 percent). In Daejeon, Bacillus sp. was highly prevalent (12.4 percent). In Busan, Micrococcus sp. was highly prevalent (22.8 percent). In Gwangju, Bacillus sp. was 9.35%. In Gyeonggi, Micrococcus sp. was 13.7%, and in Gwangju and Jeju, Micrococcus sp. was 11.2 percent and 92%. All in all, Micrococcus sp. and Bacillus sp. were highly detected throughout the entire region and multi-use facilities. Next, whether or not these airborne bacteria could influence the health of people was examined using HaCat human skin cell line which is human epithermal Karatinocytes related to allergic dermatitis. Among these isolated microorganisms, the HaCat cell proliferation was decreased by Arthrobacter sp., Bacillus sp., Brachybacterium sp., Brevundimonas sp., Kocuria sp., Mammaliicoccus sp., Norcardia sp., Prestia sp., Phychrobacillus sp., and Rhodococcus sp., while it was affected by the other bacteria. Therefore, these results have suggested that the airborne floating bacteria could be considered as the marker for the environmental risk management against atopic dermatitis, and it is needed for controlling the bacteria number that suppressed the proliferation of HaCat cells. .

A Detection of Airborne Particles Carrying Viable Bacteria in an Urban Atmosphere of Japan

Hara, Kazutaka,Zhang, Daizhou,Yamada, Maromu,Matsusaki, Hiromi,Arizono, Koji Korean Society for Atmospheric Environment 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.3

Viable bacteria on water-insoluble airborne particles were detected in the urban atmosphere of Kumamoto ($134^{\circ}45'E$, $32^{\circ}28'N$), Japan, in autumn 2008. Airborne particles were collected onto film-covered Cu meshes under clear weather conditions. The samples were stained by fluorescent stains, and then viewed and photographed with an epifluorescent microscope. Non-biological and bacterial parts in particles larger than 0.8 ${\mu}m$ were distinguished by their morphologies, fluorescent colors and fluorescent intensities. Bacterial viable statuses were discriminated according to cell membrane damage. In total, 2681 particles were investigated and it was found that 78 airborne particles were associated with bacteria. Viable bacteria were identified on 48 particles. A few particles carried multiple viable bacteria. These results provide the evidence that airborne particles act as carriers of viable bacteria in the atmosphere.

A Detection of Airborne Particles Carrying Viable Bacteria in an Urban Atmosphere of Japan

Kazutaka Hara,Daizhou Zhang,Maromu Yamada,Hiromi Matsusaki,Koji Arizono 한국대기환경학회 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.3

Viable bacteria on water-insoluble airborne particles were detected in the urban atmosphere of Kumamoto (134^ㅇ45′E, 32^ㅇ28′N), Japan, in autumn 2008. Airborne particles were collected onto film-covered Cu meshes under clear weather conditions. The samples were stained by fluorescent stains, and then viewed and photographed with an epifluorescent microscope. Non-biological and bacterial parts in particles larger than 0.8 μm were distinguished by their morphologies,fluorescent colors and fluorescent intensities. Bacterial viable statuses were discriminated according to cell membrane damage. In total, 2681 particles were investigated and it was found that 78 airborne particles were associated with bacteria. Viable bacteria were identified on 48 particles. A few particles carried multiple viable bacteria. These results provide the evidence that airborne particles act as carriers of viable bacteria in the atmosphere.

가정용 가습기의 사용자 습관에 따른 실내공기 중 바이오에어로졸의 발생특성

김익현,김기연,김대근,Kim, Ik-Hyeon,Kim, Ki Youn,Kim, Daekeun 한국환경보건학회 2012 한국환경보건학회지 Vol.38 No.6

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.

The development of paper discs immobilized with luciferase/D-luciferin for the detection of ATP from airborne bacteria

Nguyen, Dung T.,Kim, Hye Ri,Jung, Jae Hee,Lee, Kang-Bong,Kim, Byoung Chan Elsevier 2018 Sensors and actuators. B Chemical Vol.260 No.-

<P><B>Abstract</B></P> <P>The presence of various microbes in the air is one of the main causes of respiratory diseases or ailments affecting the health of humans and livestock. Therefore, early identification and detection of microorganisms in the air are key to preventing the risk associated with microbial infection. In this study, we prepared paper discs (diameter = 0.5 cm) immobilized with luciferase/D-luciferin and found that these discs could be used to determine the adenosine triphosphate (ATP) directly from the heat-lysates of airborne bacteria. The repetition of sequential adsorption/drying of the mixture solution (luciferase and D-luciferin) was performed using paper disc. The storage stability of the paper discs at room temperature was maintained for one month following their preparation while the storage stability of the liquid-based ATP assay not maintained even for one day. The paper discs could detect ATP extracted from aerosolized <I>Escherichia coli</I> (<I>E. coli</I>) as low as 1.17 × 10<SUP>3</SUP> CFU/mL in pure bacteria samples or 2.32 × 10<SUP>3</SUP> CFU/mL in bacteria samples containing dust (1 mg/mL). ATP evaluation using the paper discs for detection of aerosolized bacteria may reduce the detection time to be less than 7 min after sampling. Novel paper discs immobilized with luciferase/D-luciferin will be valuable for the development of fast and sensitive sensors for early detection and enumeration of airborne microorganisms without preparation of enzyme solution for ATP assay.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The paper discs immobilized with luciferase/D-luciferin were prepared to detect ATP extracted from airborne bacteria. </LI> <LI> The immobilization of luciferase/D-luciferin in paper discs was prepared by repeats of adsorption/dry loops process. </LI> <LI> The paper discs prepared maintained storage stability over 30 days after initial preparation. </LI> <LI> The ATP extracted from bacteria by heat lysis method could be measured within 7 min using paper discs. </LI> </UL> </P>

의료폐기물 보관소 내 자외선(UV-C)램프의 살균효과

이종태 ( Lee Jong Tae ),서경오 ( Seo Kyoung Oh ),최수정 ( Choi Su Jung ) 국군의무사령부 2018 대한군진의학학술지 Vol.49 No.1

Objectives; Medical units above division and military hospitals are obliged to discharge medical waste. Because medical waste could be contaminated with various pathogens, it must be strictly controlled by wasted management law. However, liquid sterilization only once a week as presented in the guideline may be harmful due to insufficient sterilization effect. Therefore, this study is conducted to investigate the effective quantity, location and sterilization time of ultraviolet light (UV) lamp, which is easy to install and low maintenance cost, for sterilization of medical waste storage. Methods; We used UV-C lamp (220V, 40W). The airborne bacteria collected from medical waste storage were cultured and irradiated with UV at intervals of 1 meter from 1 meter to 5 meter to observe the microbial sterilization status. Results; UV intensity decreased sharply with distance form the light source. Within 5 meter of UV irradiation, all smear microorganisms are killed within 1 hour. The airborne bacteria of medical waste storage decreased 97% after 2 hours of UV irradiation. Conclusions; UV-C lamp (220V, 40W) is effective for the sterilization of medical waste storage. By irradiation for 1∼2 hours per day, it is possible to reduce 95% of airborne bacteria. Medical waste storage of military hospitals could be air - sterilized with one to three lamps via sterilization for 1∼2 hours per day.

실내공기 중 생물학적 오염물질에 관한 국내 연구 동향

허은혜,원동환,문경환,Huh, Eun-Hae,Won, Dong-Hwan,Moon, Kyong-Whan 한국환경보건학회 2012 한국환경보건학회지 Vol.38 No.4

Objectives: Indoor air quality problems in public spaces have recently become a very important issue in South Korea, because many spend a long time every day indoors. In this study, an extensive literature review was performed on the subject of suspended bacteria and fungi in public facilities. The objective of this study was to evaluate the extent and types of suspended bacteria and fungi in indoor air in South Korea. This study will provide direction to the research in the field of indoor air. Methods: Article reviews was conducted using a search engine and the following keywords; 'bacteria', 'total suspended bacteria', 'fungi' and 'indoor air' from published articles since 2000. Results: Most of the places of measurement were schools, kindergartens, childcare centers and general hospitals. The highest concentrations of total suspended bacteria and fungi were found in schools and kindergartens. Some public facilities exceeded the standard of 800 CFU/$m^3$. There were few studies on other suspended bacteria: Gram Negative Bacteria, Staphylococcus and Klebsiella pneumoniae. Conclusions: It appears that more studies with intensive controls are needed. It was found that schools and kindergartens were most susceptible to microbial indoor air pollution. These results may be able to suggest an indoor standard for suspended bacteria and fungi in South Korea.