scholarly journals Microbial Assessment of Indoor Air Quality of Ventilation Systems

2019 ◽  
pp. 1-7
Author(s):  
H. O. Stanley ◽  
B. Onwuna ◽  
C. J. Ugboma
Keyword(s):  
Indoor Air ◽  
Natural Ventilation ◽  
Airborne Bacteria ◽  
Fungal Isolates ◽  
Enterococcus Spp ◽  
Bacillus Spp ◽  
Bacteria And Fungi ◽  
Klebsiella Spp

The aim of the study was to compare the indoor levels of airborne bacteria and fungi of air conditioned (AC) buildings and naturally ventilated (NV) buildings using a Supermarket, a Laboratory and an Eatery as a case study. The predominant bacterial isolates were Staphylococcus, Micrococcus spp., Escherichia coli, Bacillus spp., Streptococcus spp., Enterococcus spp., Klebsiella spp. The fungal isolates belong to the genera Penicillium, Aspergillus, Mucor, Trichophyton, Fusarium, Candida and Chaetomium. The levels of airborne bacteria and fungi were determined using settle plate method. In AC buildings the average air levels of bacteria (supermarket: 24.2 CFU m-3; laboratory: 29.2 CFU m-3; eatery: 51.0 CFU m-3 air) were higher than in NV (respectively: 54.3 CFU m-3; 100.7 CFU m-3; 134.3 CFU m-3 air). The average air levels for fungal isolates were higher in the eatery due to presence of poorly maintained AC system (supermarket: 7.8 CFU m-3; laboratory: 11.5 CFU m-3; eatery: 56.7 CFU m-3 air) than in NV (28.6 CFU m-3; 19.6 CFU m-3; 13.5 CFU m-3 air respectively). Findings from this study showed that AC buildings had lower levels of bacterial and fungal contamination compared to buildings with natural ventilation.

Assessment of the indoor air quality based on airborne bacteria and fungi measurements in a public school of Istanbul

2020 ◽  
Vol 13 (24) ◽  
Author(s):  
Nuket Sivri ◽  
Ahmet Ozgur Dogru ◽  
Arzu Funda Bagcigil ◽  
Kemal Metiner ◽  
Dursun Zafer Seker
Keyword(s):  
Air Quality ◽  
Public School ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Airborne Bacteria ◽  
Bacteria And Fungi

A Study on the Performance of Stratified Air Conditioning Design in Assembly Halls – A Case Study at the Dazhi Cultural Center in Taiwan

2013 ◽  
Vol 368-370 ◽  
pp. 599-602 ◽  
Author(s):  
Ian Hung ◽  
Hsien Te Lin ◽  
Yu Chung Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Air ◽  
Air Conditioning ◽  
Cfd Simulation ◽  
Indoor Temperature ◽  
Cultural Center ◽  
Computational Fluid Dynamics Cfd

This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.

An Attempt to Improve Air Quality in Primary Schools

2017 ◽  
Author(s):  
Marek Telejko ◽  
Ewa Zender-Swiercz
Keyword(s):  
Air Quality ◽  
Primary School ◽  
Indoor Air ◽  
Primary Schools ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Co2 Concentration ◽  
School Buildings ◽  
Maximum Value

Most primary school buildings in Poland rely on natural ventilation. This fact is attributed to the age of these buildings constructed more than dozen or even several tens of years ago. Few of them were fitted with a mechanical ventilation system allowing for the adjustment of microclimate parameters. The national requirements for gravity ventilation provide general guidelines, specifying strict description only for the airtightness of windows and doors and the minimum airflow to be supplied to the rooms. The minimum airflow supplied is independent of the number of occupants and purpose of the room. Low indoor air quality (IAQ) can impact occupants’ health and lead to poor productivity or low academic performance. Therefore the provision of good IAQ in classrooms and laboratories is very important. This paper presents the results of the investigation devoted to the quality of indoor air in classrooms of selected Polish primary school. Six primary school in a town with a population of 200 000 inhabitants were involved in the investigations. The participating school buildings were built between 1976 and 1994 and had gravity ventilation systems. The variability of basic IAQ parameters, i.e., temperature, relative humidity and carbon dioxide level, was analysed and the assessment of the classrooms in terms of microbiological purity was performed. The outcomes confirmed the low quality of the indoor air in these buildings. The maximum value of CO2 concentration amounted to more than 4000 ppm. Certain modifications aimed at improving IAQ were proposed during the investigations. Two solutions were implemented. The results of this study indicate that the proposed solution offers the potential to improve IAQ within classrooms.

scholarly journals Bacterial Contamination of Street Vended Food Pani Puri Available in Janakpurdham, Dhanusha

2019 ◽  
Vol 6 ◽  
pp. 70-75
Author(s):  
Nagendra Prasad Yadav ◽  
Rakesh Kumar Yadav ◽  
Satyam Prakash
Keyword(s):  
Escherichia Coli ◽  
Pathogenic Bacteria ◽  
Bacterial Contamination ◽  
Food Samples ◽  
Microbial Count ◽  
Microbiology Laboratory ◽  
Dilution Technique ◽  
Bacillus Spp ◽  
Klebsiella Spp

Objectives: To determine the level of bacterial contamination in food (Panipuri) available in market of Janakpur, Dhanusha, Nepal. Methods: Total 120 samples of Panipuri (60 solid matters and 60 masalaa Pani) collected aseptically from the market were transported to the microbiology laboratory and processed for microbial count by serial dilution technique. Microbial load and presence of pathogen were detected in each sample. Results: Analysis of the food samples revealed that 70% of Panipuri samples had high loads of bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Klebsiella spp, Pseudomonas spp, Bacillus spp.  Conclusion: This study depicted that the street vended food Panipuri of Janakpur are highly contaminated with pathogenic bacteria which can cause health risk to consumers. Thus, it is suggested that regular monitoring of the quality of street foods must be practiced to avoid any food bone illness in future.

scholarly journals Low Polluting Building Materials and Ventilation for Good Air Quality in Residential Buildings: A Cost–Benefit Study

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 102 ◽  
Author(s):  
Francesco Babich ◽  
Ingrid Demanega ◽  
Francesca Avella ◽  
Annamaria Belleri
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Building Materials ◽  
Cost Benefit Analysis ◽  
Residential Buildings ◽  
Cost Benefit ◽  
Capital Cost ◽  
Ventilation Rates

Nowadays, people spend an average of 87% of their time inside buildings, and about 69% at home. Hence, it is essential to ensure the highest possible level of indoor air quality (IAQ). Providing that the quality of the outdoor air is acceptable, the IAQ level is improved by increasing the ventilation rates. However, this means that a larger volume of air must be cooled down or warmed up to ensure the same level of thermal comfort. The aim of this study was to conduct a cost–benefit analysis of the IAQ in residential buildings. A case-study building was defined, and three sets of materials with different pollution emission levels were chosen: High, low, and very low. For each option, the ventilation rates required to have the same IAQ level were calculated, and the consequent energy consumption and costs were estimated by means of dynamic thermal simulation. The results show the range of the initial capital cost that could be compensated for by lower running costs, and the effect of each energy and economic input assumption on the appraisal of the affordable capital cost. In the discussion, insights into the IAQ co-benefits are also given.

Characterization of Bacteria and Fungi Bioaerosol in the Indoor Air of selected Primary Schools in Malaysia

2011 ◽  
Vol 20 (6) ◽  
pp. 607-617 ◽  
Author(s):  
Nor Husna Mat Hussin ◽  
Lye Munn Sann ◽  
Mariana Nor Shamsudin ◽  
Zailina Hashim
Keyword(s):  
Indoor Air ◽  
Primary Schools ◽  
Average Concentration ◽  
Outdoor Air ◽  
Inadequate Ventilation ◽  
Bacillus Spp ◽  
Bacteria And Fungi ◽  
Staphylococcus Spp ◽  
Indoor And Outdoor

This study reports the types and concentrations of bacterial and fungal bioaerosols found in five randomly selected primary schools in Malaysia. Normal flora bacteria was the most frequently isolated bacteria including Staphylococcus spp., Pseudomonas spp. and Bacillus spp. Terribacillus spp. found in this study had never been reported before. The most frequently isolated fungal genera were Aspergillus, Penicillium, Fusarium, Rhizopus and Zygomycetes. The average concentration of bacteria in indoor and outdoor air were 1025 ± 612 CFU/m3 and 1473 ± 1261 CFU/m3, respectively, while the average concentration of fungal bioaerosol in indoor and outdoor air were 292 ± 83 CFU/m3 and 401 ± 235 CFU/m3, respectively. The percentages of bacterial and fungal samples that were within the American Conference of Industrial Hygenists (ACGIH) recommended levels were 44% and 33.8%, respectively. The ratio of indoor to outdoor fungi concentration was below 1.0, suggesting minimal indoor generative source for fungal bioaerosols. However, the ratio of indoor to outdoor bacteria concentration was approaching 1.0, suggesting the presence of potential internal generative source and inadequate ventilation. Building occupants might be one of the potential sources of bacteria in the indoor air as the bacteria concentrations without occupants were significantly lower than with occupants (p < 0.05).

scholarly journals Bacterial Assessment of Unpasteurized Fruit Juices Sold in Port Harcourt, Nigeria

2020 ◽  
pp. 1-7
Author(s):  
Constancy Prisca Aleru ◽  
Vivian Nkemkanma Agi ◽  
Kingsley Njoku
Keyword(s):  
Fruit Juices ◽  
Plate Count ◽  
Heterotrophic Plate Count ◽  
E Coli ◽  
Port Harcourt ◽  
Bacillus Spp ◽  
Tiger Nuts ◽  
Staphylococcus Spp ◽  
Klebsiella Spp

This study assessed the bacterial quality of fresh fruit juices sold in some restaurants in Port Harcourt, Nigeria. A total of twenty (20) fruit juice samples were collected from four (4) different types of fruit juices sold at four (4) different restaurants. The fruits that were used for this study are: Orange, Watermelon, Pineapple and Tiger nuts. Samples of the fruit juices were collected for bacteriological assessment using heterotrophic plate count and most probable number techniques, while CHRO Magar for E. coli and other coliforms was used for the detection of E. coli. The results showed that E. coli, Bacillus spp, Klebsiella spp, Streptococcus spp and Staphylococcus spp were present in the fruit juices. The results of the heterotrophic plate count showed that the bacterial count ranged from 2.7 x 102 (Orange) to 7.1 x 103 (Tiger nuts), while the results of the total coliform count ranged from 11 MPN/100 ml to 28 MPN/100 ml. However, the study revealed that the total E. coli count ranged from 0 to 7. The number of E. coli in each of the fruit juices and restaurants ranged from 6 to 13, Bacillus spp 12 to 19, Klebsiella spp 4 to 10, Streptococcus spp 6 to 11 and Staphylococcus spp 4 to 13. Bacillus spp had the highest percentage (31.4%), followed by Staphylococcus spp (20.1%). The highest percentage of bacteria was recovered from Tiger nuts (29.4%), followed by Watermelon (28.4%). Regular monitoring of the quality of fresh fruit juices sold in restaurants in Port Harcourt and other parts of Nigeria should therefore be enforced.

scholarly journals A systematic review and meta-analysis of indoor bioaerosols in hospitals: The influence of heating, ventilation, and air conditioning

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259996
Author(s):  
Rongchen Dai ◽  
Shan Liu ◽  
Qiushuang Li ◽  
Hanting Wu ◽  
Li Wu ◽  
...  
Keyword(s):  
Air Quality ◽  
Air Conditioning ◽  
High Efficiency ◽  
Practical Implication ◽  
Meta Analysis ◽  
Hvac Systems ◽  
Cochrane Library ◽  
Airborne Bacteria ◽  
Bacteria And Fungi

Objectives To evaluate (1) the relationship between heating, ventilation, and air conditioning (HVAC) systems and bioaerosol concentrations in hospital rooms, and (2) the effectiveness of laminar air flow (LAF) and high efficiency particulate air (HEPA) according to the indoor bioaerosol concentrations. Methods Databases of Embase, PubMed, Cochrane Library, MEDLINE, and Web of Science were searched from 1st January 2000 to 31st December 2020. Two reviewers independently extracted data and assessed the quality of the studies. The samples obtained from different areas of hospitals were grouped and described statistically. Furthermore, the meta-analysis of LAF and HEPA were performed using random-effects models. The methodological quality of the studies included in the meta-analysis was assessed using the checklist recommended by the Agency for Healthcare Research and Quality. Results The mean CFU/m3 of the conventional HVAC rooms and enhanced HVAC rooms was lower than that of rooms without HVAC systems. Furthermore, the use of the HEPA filter reduced bacteria by 113.13 (95% CI: -197.89, -28.38) CFU/m3 and fungi by 6.53 (95% CI: -10.50, -2.55) CFU/m3. Meanwhile, the indoor bacterial concentration of LAF systems decreased by 40.05 (95% CI: -55.52, -24.58) CFU/m3 compared to that of conventional HVAC systems. Conclusions The HVAC systems in hospitals can effectively remove bioaerosols. Further, the use of HEPA filters is an effective option for areas that are under-ventilated and require additional protection. However, other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi. Limitation of study Although our study analysed the overall trend of indoor bioaerosols, the conclusions cannot be extrapolated to rare, hard-to-culture, and highly pathogenic species, as well as species complexes. These species require specific culture conditions or different sampling requirements. Investigating the effects of HVAC systems on these species via conventional culture counting methods is challenging and further analysis that includes combining molecular identification methods is necessary. Strength of the study Our study was the first meta-analysis to evaluate the effect of HVAC systems on indoor bioaerosols through microbial incubation count. Our study demonstrated that HVAC systems could effectively reduce overall bioaerosol concentrations to maintain better indoor air quality. Moreover, our study provided further evidence that other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi. Practical implication Our research showed that HEPA filters are more effective at removing bioaerosols in HVAC systems than the current LAF system. Therefore, instead of opting for the more costly LAF system, a filter with a higher filtration rate would be a better choice for indoor environments that require higher air quality; this is valuable for operating room construction and maintenance budget allocation.

scholarly journals Influence of tannery wastes and the surrounding environment of tannery industries on microbial growth and proliferation

2017 ◽  
Vol 7 (1) ◽  
pp. 14-18
Author(s):  
Nayan Chandra Das ◽  
Farzana Hossaini ◽  
Saurab Kishore Munshi
Keyword(s):  
Pathogenic Bacteria ◽  
Multidrug Resistant ◽  
Salmonella Spp ◽  
Tannery Waste ◽  
Surrounding Environment ◽  
Bacillus Spp ◽  
Tannery Wastes ◽  
Bacteria And Fungi ◽  
Staphylococcus Spp ◽  
Klebsiella Spp

The present study was carried out to assess the degree of microbiological proliferation in tannery wastes and the surrounding environment of the tannery industries. In this regard, a total of 8 tannery waste (n=4) and environmental (n=4) samples were tested. All the samples contained a huge load of bacteria and fungi in an average of 108 cfu/g or ml. An extended numbers of pathogenic bacteria were recovered. Among the pathogenic bacteria, Staphylococcus spp. was predominant. Most of the samples exhibited the presence of Pseudomonas spp. Salmonella spp. and fecal coliform were found each in one sample. Bacillus spp., Escherichia coli, Klebsiella spp. and Vibrio spp. were found in few samples. The average load of the pathogens was 104 cfu/g or ml. All the pathogenic isolates were found to be multidrug resistant. Higher resistance was found against penicillin and streptomycin. Tannery waste after lather treatment sample showed antibacterial activity against all the pathogens tested. Overall, presence of pathogenic microorganisms with multidrug resistance traits may pose serious public health threats. Stamford Journal of Microbiology, Vol.7(1) 2017: 14-18

Sign in / Sign up

Export Citation Format

Share Document