1
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Zhang TT, Xu X, Lv M. Measurement and prediction of the Aspergillus niger spore detachment from a vesicle unit subjected to air-blowing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168714. [PMID: 38007138 DOI: 10.1016/j.scitotenv.2023.168714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/17/2023] [Accepted: 11/18/2023] [Indexed: 11/27/2023]
Abstract
Detachment of fungal spores from growing colonies results in human exposure. Thus far, the distribution of the binding forces of the spores in a fungal unit is unknown, so that precise prediction of the spores detachment is quite challenging. This investigation used centrifugal separation to measure the binding forces of the spores. Aspergillus niger (A. niger) colonies on a culture plate were placed in a centrifuge, the detached spores were counted, and this number was used to obtain the distribution of binding forces. Next, the air-blowing of an A. niger unit was modeled by computational fluid dynamics (CFD). A spore was judged to be detached if the air-imposed drag force was greater than the binding force. For model validation, the predicted spore detachment ratios were compared with the ratios measured in a wind tunnel test. The results revealed that the binding forces of the spores obeyed the log-normal distribution. The binding forces of the distal spores from colonies with a growth age of 66 h ranged from 0 nN to 4.0 nN and had a mean of 0.65 nN. The CFD modeling predicted the detachment ratios of the distal spores with good accuracy.
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Affiliation(s)
- Tengfei Tim Zhang
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China; School of Civil Engineering, Dalian University of Technology, Dalian, China.
| | - Xinzi Xu
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Mengqiang Lv
- Tianjin Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
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2
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Nie C, Geng X, Zhang R, Wang L, Li L, Chen J. Abundant Cyanobacteria in Autumn Adhering to the Heating, Ventilation, and Air-Conditioning (HVAC) in Shanghai. Microorganisms 2023; 11:1835. [PMID: 37513007 PMCID: PMC10386019 DOI: 10.3390/microorganisms11071835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Cyanobacteria are ever-present, mainly flourishing in aquatic environments and surviving virtually in other habitats. The microbiota of indoor dust on the pre-filter of heating, ventilation, and air-conditioning (HVAC) systems, which reflect indoor microbial contamination and affect human health, has attracted attention. Contemporary studies on cyanobacteria deposited on the pre-filter of HVAC remain scant. By the culture-independent approach of qPCR and high throughput sequencing technologies, our results documented that the cyanobacterial concentrations were highest in autumn, occurred recurrently, and were about 2.60 and 10.57-fold higher than those in winter and summer. We proposed that aquatic and terrestrial cyanobacteria contributed to the pre-filter of HVAC by airborne transportation produced by wave breaks, bubble bursts, and soil surface by wind force, owing to the evidence that cyanobacteria were commonly detected in airborne particulate matters. The cyanobacteria community structure was characterized in Shanghai, where Chroococcidiopsaceae, norank_cyanobacteriales, Nostocaceae, Paraspirulinaceae, and others dominated the dust on the pre-filter of HVAC. Some detected genera, including Nodularia sp., Pseudanabaena sp., and Leptolyngbya sp., potentially produced cyanobacterial toxins, which need further studying to determine their potential threat to human health. The present work shed new insight into cyanobacteria distribution in the specific environment besides aquatic habitats.
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Affiliation(s)
- Changliang Nie
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200438, China
| | - Xueyun Geng
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200438, China
| | - Runqi Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200438, China
| | - Lina Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200438, China
| | - Ling Li
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200438, China
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science & Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200438, China
- IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather/Climate Extremes Impact and Public Health, Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
- Institute of Eco-Chongming (IEC), Shanghai 200062, China
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3
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Satari L, Iglesias A, Porcar M. The Microbiome of Things: Appliances, Machines, and Devices Hosting Artificial Niche-Adapted Microbial Communities. Microorganisms 2023; 11:1507. [PMID: 37375009 DOI: 10.3390/microorganisms11061507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 05/25/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
As it is the case with natural substrates, artificial surfaces of man-made devices are home to a myriad of microbial species. Artificial products are not necessarily characterized by human-associated microbiomes; instead, they can present original microbial populations shaped by specific environmental-often extreme-selection pressures. This review provides a detailed insight into the microbial ecology of a range of artificial devices, machines, and appliances, which we argue are specific microbial niches that do not necessarily fit in the "build environment" microbiome definition. Instead, we propose here the Microbiome of Things (MoT) concept analogous to the Internet of Things (IoT) because we believe it may be useful to shed light on human-made, but not necessarily human-related, unexplored microbial niches.
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Affiliation(s)
- Leila Satari
- Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, 46980 Paterna, Spain
| | - Alba Iglesias
- Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, 46980 Paterna, Spain
| | - Manuel Porcar
- Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, 46980 Paterna, Spain
- Darwin Bioprospecting Excellence SL., Parc Científic, Universitat de València, 46980 Paterna, Spain
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4
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Watanabe K, Yanagi U, Shiraishi Y, Harada K, Ogino F, Asano K. Bacterial Communities in Various Parts of Air-Conditioning Units in 17 Japanese Houses. Microorganisms 2022; 10:microorganisms10112246. [PMID: 36422316 PMCID: PMC9697849 DOI: 10.3390/microorganisms10112246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
HVAC systems have a significant impact on the indoor environment, and microbial contamination in HVAC systems has a significant effect on the indoor air quality. In this study, to gain a better understanding of the microbial contamination inside ACs, we used NGS to analyze the 16S rRNA gene of bacteria adhering to AC filters, cooling coils, fans, and air outlet surfaces. The five phyla in terms of the highest relative abundance were Proteobacteria, Firmicutes, Actinobacteria, Cyanobacteria, and Bacteroidetes. The surface of an AC filter provides a history of indoor airborne bacterial contamination, and of the 10 bacterial genera we detected with the highest abundance (in the following order: Pseudomonas > Staphylococcus > Paracoccus > Corynebacterium > Acinetobacter > Streptococcus > Methylobacterium > Enhydrobacter > Sphingomonas > Actinotignum) on the filter surface, the top 6 genera were Gram-negative bacteria. Furthermore, the seventh-most abundant genus adhering to the filter surface (Methylobacterium) was the second-most abundant genus on the cooling coil and fan, and the ninth-most abundant genus on the air filter (Sphingomonas) was the third-most abundant genus on the cooling coil. Various factors impact the bacterial flora inside AC units, including the location of the house, AC unit usage, and occupant activity.
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Affiliation(s)
- Kensuke Watanabe
- Graduate School of Engineering, Kogakuin University, Tokyo 163 8677, Japan
| | - U Yanagi
- School of Architecture, Kogakuin University, Tokyo 163 8677, Japan
- Correspondence: ; Tel.: +81-(03)-3340-1468
| | - Yoshiki Shiraishi
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara 259 1193, Japan
| | - Kazuhiro Harada
- Research & Development, Duskin Co., Ltd., Osaka 564 0043, Japan
| | - Fumitoshi Ogino
- Research & Development, Duskin Co., Ltd., Osaka 564 0043, Japan
| | - Koichiro Asano
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara 259 1193, Japan
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5
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Okada N, Shiraishi Y, Tomomatsu K, Oguma T, Asano K. Moldy odor from air conditioners in the residences of Japanese participants with and without asthma. INDOOR AIR 2022; 32:e13156. [PMID: 36437655 DOI: 10.1111/ina.13156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/08/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Fungi, a major allergen associated with asthma onset and severity, can contaminate air conditioners if not properly maintained. We surveyed the prevalence and risk factors associated with fungal contamination of air conditioners and patient behavior to reduce this contamination. Japanese adults aged ≥30 years registered in the database of an Internet research company were asked to participate in an online survey. A moldy odor from the air conditioners in their residences was used as an indicator of fungal contamination. Among a total of 1006 adults, including 631 patients with asthma, 37.1% reported a moldy odor from air conditioners. The prevalence was higher in residences with indoor condensation and in air conditioners used for ≥6 years or frequently during the summer, but was lower in air conditioners with an auto-cleaning function. The risk of indoor condensation was higher in apartments, in the presence of an aquarium, and in the absence of a 24-h ventilation system. These risk factors did not differ between the residences or air conditioners of participants with and without asthma. Asthmatic patients were conscious of indoor air quality; however, do not necessarily take appropriate measures to reduce indoor mold contamination, possibly due to a lack of knowledge. In conclusion, appropriate patient education is required to reduce environmental fungal contamination and improve asthma control.
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Affiliation(s)
- Naoki Okada
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Yoshiki Shiraishi
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Katsuyoshi Tomomatsu
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Tsuyoshi Oguma
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara, Japan
| | - Koichiro Asano
- Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Isehara, Japan
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6
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Li X, Liu D, Yao J. Aerosolization of fungal spores in indoor environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 820:153003. [PMID: 35031366 DOI: 10.1016/j.scitotenv.2022.153003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Fungi in indoor environments can cause adverse health effects through inhalation and epidermal exposure. The risk of fungal exposure originates from the aerosolization of fungal spores. However, spore aerosolization is still not well understood. This paper provides a review of indoor fungal contamination, especially the aerosolization of fungal spores. We attempted to summarize what is known today and to identify what more information is needed to predict the aerosolization of fungal spores. This paper first reviews fungal contamination in indoor environments and HVAC systems. The detachment of fungal spores from colonies and the spore aerosolization principle are then summarized. Based on the above discussion, prediction methods for spore aerosolization are discussed. This review further clarifies the current situation and future efforts required to accurately predict spore aerosolization. This information is useful for forecasting and controlling the aerosolization of fungal spores.
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Affiliation(s)
- Xian Li
- School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China.
| | - Dan Liu
- School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China
| | - Jian Yao
- School of Civil Engineering and Architecture, Linyi University, Linyi 276000, China
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7
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Schwartz-Narbonne H, Abbatt JPD, DeCarlo PF, Farmer DK, Mattila JM, Wang C, Donaldson DJ, Siegel JA. Modeling the Removal of Water-Soluble Trace Gases from Indoor Air via Air Conditioner Condensate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10987-10993. [PMID: 34342979 DOI: 10.1021/acs.est.1c02053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Water-soluble trace gas (WSTG) loss from indoor air via air conditioning (AC) units has been observed in several studies, but these results have been difficult to generalize. In the present study, we designed a box model that can be used to investigate and estimate WSTG removal due to partitioning to AC coil condensate. We compared the model output to measurements of a suite of organic acids cycling in an indoor environment and tested the model by varying the input AC parameters. These tests showed that WSTG loss via AC cycling is influenced by Henry's law constant of the compound in question, which is controlled by air and water temperatures and the condensate pH. Air conditioning unit specifications also impact WSTG loss through variations in the sensible heat ratio, the effective recirculation rate of air through the unit, and the timing of coil and fan operation. These findings have significant implications for indoor modeling. To accurately model the fate of indoor WSTGs, researchers must either measure or otherwise account for these unique environmental and operational characteristics.
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Affiliation(s)
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
| | - Peter F DeCarlo
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - James M Mattila
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Chen Wang
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
| | - D James Donaldson
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
| | - Jeffrey A Siegel
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, Ontario, Canada M5S 1A4
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada M5T 3M7
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8
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Sheu R, Fortenberry CF, Walker MJ, Eftekhari A, Stönner C, Bakker A, Peccia J, Williams J, Morrison GC, Williams BJ, Gentner DR. Evaluating Indoor Air Chemical Diversity, Indoor-to-Outdoor Emissions, and Surface Reservoirs Using High-Resolution Mass Spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10255-10267. [PMID: 34270218 PMCID: PMC8461992 DOI: 10.1021/acs.est.1c01337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Detailed offline speciation of gas- and particle-phase organic compounds was conducted using gas/liquid chromatography with traditional and high-resolution mass spectrometers in a hybrid targeted/nontargeted analysis. Observations were focused on an unoccupied home and were compared to two other indoor sites. Observed gas-phase organic compounds span the volatile to semivolatile range, while functionalized organic aerosols extend from intermediate volatility to ultra-low volatility, including a mix of oxygen, nitrogen, and sulfur-containing species. Total gas-phase abundances of hydrocarbon and oxygenated gas-phase complex mixtures were elevated indoors and strongly correlated in the unoccupied home. While gas-phase concentrations of individual compounds generally decreased slightly with greater ventilation, their elevated ratios relative to controlled emissions of tracer species suggest that the dilution of gas-phase concentrations increases off-gassing from surfaces and other indoor reservoirs, with volatility-dependent responses to dynamically changing environmental factors. Indoor-outdoor emissions of gas-phase intermediate-volatility/semivolatile organic hydrocarbons from the unoccupied home averaged 6-11 mg h-1, doubling with ventilation. While the largest single-compound emissions observed were furfural (61-275 mg h-1) and acetic acid, observations spanned a wide range of individual volatile chemical products (e.g., terpenoids, glycol ethers, phthalates, other oxygenates), highlighting the abundance of long-lived reservoirs resulting from prior indoor use or materials, and their gradual transport outdoors.
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Affiliation(s)
- Roger Sheu
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
| | - Claire F Fortenberry
- Department of Energy, Environmental, & Chemical Engineering and Center for Aerosol Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Michael J Walker
- Department of Energy, Environmental, & Chemical Engineering and Center for Aerosol Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Azin Eftekhari
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27515, United States
| | - Christof Stönner
- Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Alexa Bakker
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
| | - Jordan Peccia
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
| | - Jonathan Williams
- Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Glenn C Morrison
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27515, United States
| | - Brent J Williams
- Department of Energy, Environmental, & Chemical Engineering and Center for Aerosol Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Drew R Gentner
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
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9
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Zhao P, Li Y. Modeling and Experimental Validation of Microbial Transfer via Surface Touch. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4148-4161. [PMID: 33378200 DOI: 10.1021/acs.est.0c04678] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Surface touch spreads disease-causing microbes, but the measured rates of microbial transfer vary significantly. Additionally, the mechanisms underlying microbial transfer via surface touch are unknown. In this study, a new physical model was proposed to accurately evaluate the microbial transfer rate in a finger-surface touch, based on the mechanistic effects of important physical factors, including surface roughness, surface wetness, touch force, and microbial transfer direction. Four surface-touch modes were distinguished, namely, a single touch, sequential touches (by different recipients), repeated touches (by the same recipient), and a touch with rubbing. The tested transfer rates collated from 26 prior studies were compared with the model predictions based on their experimental parameters, and studies in which the transfer rates were more consistent with our model predictions were identified. New validation experiments were performed by accurately controlling the parameters involved in the model. Four types of microbes were used to transfer between the naked finger and metal surface with the assistance of a purpose-made touch machine. The measured microbial transfer rate data in our new experiments had a smaller standard deviation than those reported from prior studies and were closer to the model prediction. Our novel predictive model sheds light on possible future studies.
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Affiliation(s)
- Pengcheng Zhao
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China
- School of Public Health, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China
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10
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Haines SR, Siegel JA, Dannemiller KC. Modeling microbial growth in carpet dust exposed to diurnal variations in relative humidity using the "Time-of-Wetness" framework. INDOOR AIR 2020; 30:978-992. [PMID: 32403157 PMCID: PMC7496831 DOI: 10.1111/ina.12686] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/24/2020] [Accepted: 05/02/2020] [Indexed: 06/11/2023]
Abstract
Resuspension of microbes in floor dust and subsequent inhalation by human occupants is an important source of human microbial exposure. Microbes in carpet dust grow at elevated levels of relative humidity, but rates of this growth are not well established, especially under changing conditions. The goal of this study was to model fungal growth in carpet dust based on indoor diurnal variations in relative humidity utilizing the time-of-wetness framework. A chamber study was conducted on carpet and dust collected from 19 homes in Ohio, USA and exposed to varying moisture conditions of 50%, 85%, and 100% relative humidity. Fungal growth followed the two activation regime model, while bacterial growth could not be evaluated using the framework. Collection site was a stronger driver of species composition (P = 0.001, R2 = 0.461) than moisture conditions (P = 0.001, R2 = 0.021). Maximum moisture condition was associated with species composition within some individual sites (P = 0.001-0.02, R2 = 0.1-0.33). Aspergillus, Penicillium, and Wallemia were common fungal genera found among samples at elevated moisture conditions. These findings can inform future studies of associations between dampness/mold in homes and health outcomes and allow for prediction of microbial growth in the indoor environment.
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Affiliation(s)
- Sarah R. Haines
- Environmental Science Graduate ProgramOhio State UniversityColumbusOhioUSA
- Department of Civil, Environmental & Geodetic EngineeringCollege of EngineeringOhio State UniversityColumbusOhioUSA
- Division of Environmental Health SciencesCollege of Public HealthOhio State UniversityColumbusOhioUSA
| | - Jeffrey A. Siegel
- Department of Civil and Mineral EngineeringUniversity of TorontoTorontoONCanada
| | - Karen C. Dannemiller
- Department of Civil, Environmental & Geodetic EngineeringCollege of EngineeringOhio State UniversityColumbusOhioUSA
- Division of Environmental Health SciencesCollege of Public HealthOhio State UniversityColumbusOhioUSA
- Sustainability InstituteOhio State UniversityColumbusOhioUSA
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11
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Bakker A, Siegel JA, Mendell MJ, Prussin AJ, Marr LC, Peccia J. Bacterial and fungal ecology on air conditioning cooling coils is influenced by climate and building factors. INDOOR AIR 2020; 30:326-334. [PMID: 31845419 DOI: 10.1111/ina.12632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/06/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
The presence of biofilms on the cooling coils of commercial air conditioning (AC) units can significantly reduce the heat transfer efficiency of the coils and may lead to the aerosolization of microbes into occupied spaces of a building. We investigated how climate and AC operation influence the ecology of microbial communities on AC coils. Forty large-scale commercial ACs were considered with representation from warm-humid and hot-dry climates. Both bacterial and fungal ecologies, including richness and taxa, on the cooling coil surfaces were significantly impacted by outdoor climate, through differences in dew point that result in increased moisture (condensate) on coils, and by the minimum efficiency reporting value (MERV 8 vs MERV 14) of building air filters. Based on targeted qPCR and sequence analysis, low efficiency upstream filters (MERV 8) were associated with a greater abundance of pathogenic bacteria and medically relevant fungi. As the implementation of air conditioning continues to grow worldwide, better understanding of the factors impacting microbial growth and ecology on cooling coils should enable more rational approaches for biofilm control and ultimately result in reduced energy consumption and healthier buildings.
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Affiliation(s)
- Alexa Bakker
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA
| | - Jeffrey A Siegel
- Department of Civil & Mineral Engineering, The University of Toronto, Toronto, ON, Canada
- Dalla Lana School of Public Health, The University of Toronto, Toronto, ON, Canada
| | - Mark J Mendell
- California Department of Public Health, Environmental Health Laboratory Branch, Richmond, CA, USA
| | - Aaron J Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Jordan Peccia
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA
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12
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Quantitative evaluation of bioaerosols in different particle size fractions in dust collected on the International Space Station (ISS). Appl Microbiol Biotechnol 2019; 103:7767-7782. [PMID: 31388730 DOI: 10.1007/s00253-019-10053-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/17/2019] [Accepted: 07/26/2019] [Indexed: 12/20/2022]
Abstract
Exposure to bioaerosols can adversely influence human health through respiratory tract, eye, and skin irritation. Bioaerosol composition is unique on the International Space Station (ISS), where the size distribution of particles in the air differs from those on Earth. This is due to the lack of gravitational settling and sources of biological particles. However, we do not understand how microbes are influenced by particle size in this environment. We analyzed two types of samples from the ISS: (1) vacuum bag debris which had been sieved into five different size fractions and (2) passively collected particles on a tape substrate with a passive aerosol sampler. Using quantitative polymerase chain reaction (qPCR), the highest concentration of fungal spores was found in the 106-150 μm-sized sieved dust particles, while the highest concentration of bacterial cells was found in the 150-250 μm-sized sieved dust particles. Illumina MiSeq DNA sequencing revealed that particle size was associated with bacterial and fungal communities and statistically significant (p = 0.035, p = 0.036 respectively). Similar fungal and bacterial species were found within the passive aerosol sample and the sieved dust samples. The most abundant fungal species identified in the aerosol and sieved samples are commonly found in food and plant material. Abundant bacterial species were most associated with the oral microbiome and human upper respiratory tract. One limitation to this study was the suboptimal storage conditions of the sieved samples prior to analysis. Overall, our results indicate that microbial exposure in space may depend on particle size. This has implications for ventilation and filtration system design for future space vehicles and habitats.
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13
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Duncan SM, Tomaz S, Morrison G, Webb M, Atkin J, Surratt JD, Turpin BJ. Dynamics of Residential Water-Soluble Organic Gases: Insights into Sources and Sinks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:1812-1821. [PMID: 30633495 PMCID: PMC7279883 DOI: 10.1021/acs.est.8b05852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Water-soluble organic gas (WSOG) concentrations are elevated in homes. However, WSOG sources, sinks, and concentration dynamics are poorly understood. We observed substantial variations in 23 residential indoor WSOG concentrations measured in real time in a North Carolina, U.S., home over several days with a high-resolution time-of-flight chemical ionization mass spectrometer equipped with iodide reagent ion chemistry (I-HR-ToF-CIMS). Concentrations of acetic, formic, and lactic acids ranged from 30-130, 15-53, and 2.5-360 μg m-3, respectively. Concentrations of several WSOGs, including acetic and formic acids, decreased considerably (∼30-50%) when the air conditioner (AC) cycled on, suggesting that the AC system is an important sink for indoor WSOGs. In contrast to nonpolar organic gases, indoor WSOG loss rate coefficients were substantial for compounds with high oxygen-to-carbon (O/C) ratios (e.g., 1.6-2.2 h-1 for compounds with O/C > 0.75 when the AC system was off). Loss rate coefficients in the AC system were more uncertain but were estimated to be 1.5 h-1. Elevated concentrations of lactic acid coincided with increased human occupancy and cooking. We report several WSOGs emitted from cooking and cleaning as well as transported in from outdoors. In addition to indoor air chemistry, these results have implications to exposure and human health.
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Affiliation(s)
- Sara M. Duncan
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Environmental Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Sophie Tomaz
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Glenn Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marc Webb
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Joanna Atkin
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jason D. Surratt
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Barbara J. Turpin
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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