• 한국산업보건학회지
• /
• 제20권4호
• /
• pp.274-281
• /
• 2010

The objectives of this study are (a) to investigate the distribution patterns and exposure concentrations of biological agents in sawmill industries and (b) to compare sampling methods of biological agents. The representative processes of 5 sawmills were selected to measure total airborne bacteria, fungi, endotoxin as well as dust. Airborne bacteria and fungi were measured with one stage impactor, six stage impactor and gelatin filteration methods. Endotoxin was collected with polycarbonate filters and analysed by kinetic chromogenic Limulus Amebocyte Lysate method. Geometric mean levels of airborne bacteria, fungi, endotoxin and dust were 1,864 CFU/$m^3$, 2,252 CFU/$m^3$, 31.5 EU/$m^3$ and 2.4 mg/$m^3$. The ratios of indoor/outdoor concentrations were 3.7 for bacteria, 4.1 for fungi, 3.3 for endotoxin and 9.7 for dust. The respiratory fractions of bacteria were 68.0, 50.9, 49.2 and 45.1% in band-saw, table-saw, rip-saw process and outdoor air. The respiratory fractions of fungi were 78.7, 90.8, 87.5 and 84.8% in band-saw, table-saw, rip-saw process and outdoor air, respectively. There was no significant differences in bacterial concentrations among single stage, six stage impaction and filteration methods. But, fungal concentrations measured with filtration methods were significantly higher than those with impaction methods. Geometric mean levels of airborne bacteria and fungi were higher than the OSHA guideline values of 1,000 CFU/$m^3$. The respiratory fractions of fungi were above 75%. The concentrations of biological agents were significantly different among culture-based sampling methods. In the exposure assessments of biological agents, further studies are needed for the comparisons of diverse sampling methods and the investigations of environmental factors.

• 한국환경보건학회지
• /
• 제35권5호
• /
• pp.355-361
• /
• 2009

This study evaluated the bacterial concentrations and affecting factors at the laboratories of a university in Seoul, Korea. Thirty-three samples of total airborne bacteria (TAB) and eighteen samples of gram negative bacteria (GNB) were collected from both microbiology laboratories (7) and chemistry laboratories (6). GM (GSD) of TAB and GNB concentrations were 194 (2.52) $cfu/m^3$, 24 (4.1) $cfu/m^3$, respectively. TAB concentrations in the chemical laboratories (GM (GSD): 193 (2.0) $cfu/m^3$) were not significantly different from those in microbial laboratories (GM (GSD): 202 (2.7) $cfu/m^3$, (p>0.05)). GM (GSD) of TAB concentrationsat the top of sink, the center of laboratory, and the front of ventilation ventilation device within laboratories, 182 (3.2) $cfu/m^3$, 217 (2.2) $cfu/m^3$, 176 (2.4) $cfu/m^3$, respectively, were not significantly different (p=0.48). Related factors were measured such as temperature, relative humidity, floor of laboratory, number of persons and laboratory area. TAB concentrations were significantly related to temperature (r=0.36, p<0.05), and the floor of laboratory and temperature were also significantly related (r=0.49, p<0.001). However, other factors such as relative humidity, number of persons and laboratory area did not show any significant relationship with TAB concentrations (p>0.05). TAB concentrations were affected significantly by cleaning frequency (p<0.001) and floor of laboratory (p<0.05). There was also a significant difference (p<0.01) between TAB indoor concentrations and TAB outdoor concentrations. However, other factors such as general ventilation did not affect TAB concentrations (p>0.05) in this study.

• 한국환경과학회지
• /
• 제16권7호
• /
• pp.785-791
• /
• 2007

The current study evaluated the technical feasibility of the application of titanium dioxide ($TiO_{2}$) photo-catalytic air cleaners for the disinfection of bioaerosols present in indoor air. The evaluation included both laboratory and field tests and the tests of hydraulic diameter (HD) and lamp type (LT). Disinfection efficiency of photocatalytic oxidation (PCO) technique was estimated by survival ratio of bacteria or fungi calculated from the number of viable cells which form colonies on the nutrient agar plates. It was suggested that the reactor coating with $TiO_{2}$ did not enhance the adsorption of bioaerosols, and that the UV irradiation has certain extent of disinfection efficiency. The disinfection efficiency increased as HD decreased, most likely due to the decrease in the light intensity since the distance of the catalyst from the light source increased when increasing the HD. It was further suggested that the mass transfer effects were not as important as the light intensity effects on the PCO disinfection efficiency of bioaerosols. Germicidal lamp was superior to the black lamp for the disinfection of airborne bacteria and fungi, which is supported by the finding that the disinfection efficiencies were higher when the germicidal lamp was used compared to the black lamp in the laboratory test. These findings, combined with operational attributes such as a low pressure drop across the reactor and ambient temperature operation, can make the PCO reactor a possible tool in the effort to improve indoor bioaerosol levels.

• Safety and Health at Work
• /
• 제13권1호
• /
• pp.9-16
• /
• 2022

Background: The global shift toward greener societies demands new technologies and work operations in the waste-management sector. However, progressive industrial methods do not necessarily consider workers' health. This study characterized workers' exposure to bioaerosols and investigated the bioaerosols' potential to engage the immune system in vitro. Methods: Full shift personal aerosol sampling was conducted over three consecutive days. Dust load was analyzed by gravimetry, fungal and actinobacterial spores were analyzed by scanning electron microscopy, and endotoxin by limulus amebocyte lysate (LAL) assay. In vitro exposure of HEK cells to airborne dust samples was used to investigate the potential of inducing an inflammatory reaction. Results: The total dust exposure level exceeded the recommended occupational exposure limit (OEL) of 5.0 mg/m³ in 3 out of 15 samples. The inhalable endotoxin level exceeded the recommended exposure level by a 7-fold, whereas the fungal spore level exceeded the recommended exposure level by an 11-fold. Actinobacterial spores were identified in 8 out of 14 samples. In vitro experiments revealed significant TLR2 activation in 9 out of 14 samples vs. significant TLR4 activation in all samples. Conclusion: The present study showed that the dust samples contained potentially health-impairing endotoxin, fungi, and actinobacterial levels. Furthermore, the sampled dust contained microbial components capable of inducing TLR activation and thus have the potential to evoke an inflammatory response in exposed individuals.

• 한국산업보건학회지
• /
• 제10권1호
• /
• pp.115-125
• /
• 2000

Three major hospitals with over 500 beds located in and near Seoul were surveyed for airbone microorganisms from February 1, 1998 to February 18, 1998. The purpose of the study was to identify and quantify microbiological organisms circulating in the air of three different areas in the hospitals. For the study, a RCS air sampler was utilized equipped with two different collection media, the agar strip GK-A for bacteria and the agar strip HS for fungi. The areas investigated were the intensive care unit (ICU) in the Department of internal medicine, the Newborns room in the Department of Obstetrics, and the microbiology laboratory. The results were as follows; 1. The average numbers of general microbiological particles collected on the agar strip GK-A media were $205CFU/m^3$, $232CFU/m^3$, and $128CFU/m^3$ in each hospitals. The highest concentration of $387CFU/m^3$ was found in the ICU of A hospital at 15:00 during the day. Further analysis of the collected bioaerosols by gram staining, revealed that there were gram positive cocci (89.5%), gram positive bacilli (7.2%), gram negative bacilli (2.8%), and fungi (0.5%), in descending order of frequency. 2. Ten different genes were identified from the agar strip GK-A. The most frequently identified organisms were: the Coagulase negative staphylococcus (55.0%), Micrococcus (21.4%), Enterococcus species(10.4%), and Bacillus species (7.2%). A series of antibiotics susceptibility test were conducted against the aforementioned four(4) organisms. Ninety percent of coagulase negative stapylococcus were sensitive to Penicillins. Pathogenic microbes isolated include: Staphylococcus aureus, Acinetobacter species, Klebsiella pneumonia, Klebsiella oxytoca, and Pseudomonas aeroginosa. 3 Although 56.8% of the microorganisms grown on the strip HS media for fungi could not be identified, some of them were successfully identified. The most frequently found fungi were Aspergillus (35.3%), Yeast or Molds (6.2%), and Penicillium (0.7%). Based on the results obtained from the study, it was concluded that some areas in the hospitals had abnormally high bioaerosol concentrations which could be attributed to human activity. Therefore, it is recommended that periodic assessments of indoor bioaerosols aiming to identify the possible sources should be conducted in order to maintain clean indoor environment in the hospitals.

• 미생물학회지
• /
• 제41권3호
• /
• pp.188-194
• /
• 2005

미생물학적 실내공기질을 평가하기 위하여, 울산에 위치한 중${\cdot}$고등학교 3곳이 교실과 복도에서, 학기 중(수업시간, 점심시간, 방과 후)과 방학 중 등 상황별로 공기중 미생물의 농도를 조사하였다. 미생물의 포집에는 충돌식 공기 채취기를 사용하였으며, 세균수는 plate count agar, 진균수는 dichloran rose bengal chloramphenicol agar를 사용하여 측정하였고, 이들 배지로부터 세균과 진균을 분리하여 동정하였다. 학기 중 세균 농도는 점심시간의 복도에서 평균 $1,111\;MPN/m^{3}$로 가장 높았고, 수업시간의 복도에서 평균 $132\;MPN/m^{3}$로 가장 낮았으며, 방학 중의 측정값은 교실과 복도에서 각각 학기 중 수업시간의 $5{\%}$와 $27{\%}$ 수준이었다. 조사한 집락의 $60{\%}$는 병원성과 관련이 적은 Micrococcus spp.로 동정되었고. Staphylococdcus 속은 $12{\%}$를 차지하였다. 학기 중 진균의 평균 농도는 상황별로 $105{\~}213\;MPN/m^{3}$의 범위였으며, 방학 중의 측정값은 교실과 복도에서 각각 $32\;MPN/m^{3}$와 $83\;MPN/m^{3}$이었다. 공기중 진균의 집락으로부터 Cladosporium 속, Penicillium 속, Aspergillus 속 등을 확인할 수 있었으며, 언급한 3 속이 조사한 집락의 $77{\%}$를 차지하였다. 연구의 결과는 학교 실내에서 학생수와 함께 활동성과 연관된 상황에 따른 세균 농도의 변이를 보여주었으며, 학교 환경에서 bioaerosol의 허용수준을 결정함에 있어 이를 고려해야 함을 제안하고 있다.

• 한국미생물·생명공학회지
• /
• 제43권2호
• /
• pp.142-149
• /
• 2015

바이오에어로졸은 0.02-100 μm 입자로, 자연 및 인위적 환경 또는 사람의 활동에 의해 발생된다. 바이오에어로졸은 바이러스, 세균, 곰팡이, 원생생물, 곰팡이 포자, 미생물 독소, 꽃가루, 동식물 기원의 물질, 타액 또는 글루칸 등으로 구성되며, 인간과 동물에게 호흡기 등의 질환을 유발한다. 본 연구에서는 농업, 축산, 하수처리장, 해변 및 청청지역의 바이오에어로졸 시료에서 분리한 배양성 미생물을 동정 및 계통분석을 수행한 결과, 우점 및 종의 구성 등 환경 유형 별 차이가 분석되었다. 한편 모든 시료에서 31 분리주가 Bacillus cereus로 동정되었고, 실내 양계장에서 Acinetobacter baumannii가 분리되었다. 또한 농업, 축산 및 해변에서 분리한 미생물 중 Domibacillus속, Chryceobacterium속, Nocardioides속 및 Comamonadaceae과에 속하는 새로운 종 또는 속이 분리되었다.

• 한국산업보건학회지
• /
• 제26권3호
• /
• pp.324-333
• /
• 2016

Objectives: We aimed to compare the sampling performance of different flow-based impactor samplers for collecting fungal spores and bacteria and to explore the association of the level of bioaerosols with activity patterns of occupants in daycare center settings. Methods: For comparison of sampling performance, two different flow-based samplers (greater than 100 L/min or not) were selected; a low flow-based sampler (one-stage Andersen sampler) and two high flow-based samplers (DUO SAS SUPER 360 sampler, BUCK bio-culture sampler). We collected airborne mold and bacteria in 30 daycare centers with various levels of contaminated air. Three repeat samplings per each sampler were performed. Mold and bacteria were grown for 96 hours at $25{\pm}1^{\circ}C$ and 48 hours at $35{\pm}1^{\circ}C$, respectively. The Andersen and SAS samplers were used for investigating the association between the level of bioaerosols and the activity patterns of occupants in daycares. Particular matters 10($PM_{10}$), temperature, and relative humidity were monitored as well. Samplings were carried out with one-hour interval from 9 to 5 O'clock. For statistical comparisons, Kruskal-Wallis test, Wilcoxon's signed rank test, and multiple regression analysis were carried out. Results: The airborne level of molds by the low flow-based sampler were significantly higher than that of high flow-based samplers (indoor, P=0.037; outdoor, P=0.041). However, no statistical difference was observed in the airborne level of bacteria by each sampler. Also the level of bioaerosols varied by the time, particularly with different activity patterns in daycare centers. The higher level of mold and bacteria were observed in play time in indoor. Similarly, the concentrations of $PM_{10}$ were significantly associated with the level of bioaerosols (P<0.05). Conclusions: Our findings indicate that the flow rate of sampler, rather than total air volume, could be able to affect the results of sampling. Also, the level of airborne mold and bacteria vary behavior patterns of occupants in indoor of daycare settings. Therefore, different samplers with other flow rate may be selected for mold or bacteria sampling, and activity patterns should be considered for bioaerosol sampling as well.

• 미생물학회지
• /
• 제39권4호
• /
• pp.253-259
• /
• 2003

미생물학적 실내공기질을 평가하기 위하여, 울산에 위치한 3곳의 유치원을 대상으로, 2002년 4월에서 2003년 1월에 걸쳐 계절별로 공기 중의 미생물 농도를 결정하였다. 미생물의 포집에는 충돌식 공기 채취기를 사용하였으며, 세균수는 Staphylococcus medium과 plate count agar, 진균수는 dichloran rose bengal chloramphenicol agar를 사용하여 측정하였다. Staphylococcus medium에서 생장한 세균의 평균 농도는 827.0 MPN/㎥ 로 83.5~4,149.1 MPN/㎥의 범위였으며, plate count agar의 경우는 평균이 580.3 MPN/㎥로 50.0~2,636.0 MPN/㎥의 범위였다. 계절별 평균값은 여름이 가장 높았고, 가을, 봄, 겨울의 순이었으며, 세균의 집락수와 실내온도는 양의 상관관계가 있었다. 계절에 따라 그람양성의 구균은 전체 세균 집락의 45.6~61.0%, 그람음성의 막대균이 8.5~20.6%를 차지하였으며, Micrococcus spp.가 가장 우점하였다. 진균의 농도는 평균이 660.8 MPN/㎥로 0~1,887.5 MPN/㎥의 범위였으며, 계절별 평균값은 여름이 가장 높았고, 겨울이 가장 낮았다. 실내외 공기의 진균 집락으로부터 Penicillium spp.와 Aspergillus spp.를 확인할 수 있었다. 연구의 결과는 계절에 따른 미생물 농도의 변이와 학교의 실내환경에서 bioaerosol의 허용수준을 결정함에 있어 이를 고려해야 할 필요가 있음을 보여주었다.

• 한국산학기술학회논문지
• /
• 제10권9호
• /
• pp.2485-2491
• /
• 2009

2007년 4월 1일부터 5월 31일까지 2개월 동안 1개 광역도 1개 도농복합도시 지역의 노인요양시설 5곳을 대상으로 실내 외의 공기 중 바이오에어로졸 조사하기 위해 관성충돌 채취법을 적용한 미생물 채취기인 air $IDEAL^{TM}$(Biomerieux)를 이용하여 면양혈액한천배지와 Sabouraud Dextrose Ager를 사용하여 채취하여 배양하였다. 배양하여 분리 동정한 결과 다음과 같은 결과를 얻었다. 1. 각 시설별 전체 미생물의 분리는 300 L 실내에서 S 요양원이 263 cfu/$m^3$로 가장 많았고, U 요양원이 123 cfu/$m^3$로 가장 낮은 수가 분리되었다. 2. 실내에서 300 L를 채취한 배지에서 분리된 세균의 수는 기타 동정되지 않거나 비병원성 그람양성구균이 321개로 가장 많이 분리되었으며, 기타 그람양성구균의 대부분은 CNS(Coagulase Negative Staphylococcus)이었다. 3. 실내에서 300 L를 채취한 배지에서 분리된 진균의 수는 Aspergillus spp. 가 66개로 가장 많이 분리되었으며, 다음으로 Mucor spp. 62개, Penicillium spp. 53개, Alternaria spp. 50개, 기타 동정되지 않거나 비병원성 진균들이 42개의 순으로 분리되었다. 4. 실내 외의 오염비율은 실외보다는 실내에서 모두 평균 집락수가 많았으며, 300 L와 500 L의 공기량의 차이를 둔 조사에서는 공기량이 많을수록 양적으로는 많은 세균이 검출되었지만 균종으로는 큰 변화가 없었다.