1
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Seo GM, Lee H, Kang YJ, Kim D, Sung JH. Development of in vitro model of exosome transport in microfluidic gut-brain axis-on-a-chip. LAB ON A CHIP 2024; 24:4581-4593. [PMID: 39230477 DOI: 10.1039/d4lc00490f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
The gut communicates with the brain in a variety of ways known as the gut-brain axis (GBA), which is known to affect neurophysiological functions as well as neuronal disorders. Exosomes capable of passing through the blood-brain-barrier (BBB) have received attention as a mediator of gut-brain signaling and drug delivery vehicles. In conventional well plate-based experiments, it is difficult to observe the exosome movement in real time. Here, we developed a microfluidic-based GBA chip for co-culturing gut epithelial cells and neuronal cells and simultaneously observing exosome transport. The GBA-chip is aimed to mimic the in vivo situation of convective flow in blood vessels and convective and diffusive transport in the tissue interstitium. Here, fluorescence-labeled exosome was produced by transfection of HEK-293T cells with CD63-GFP plasmid. We observed in real time the secretion of CD63-GFP-exosomes by the transfected HEK-293T cells in the chip, and transport of the exosomes to neuronal cells and analyzed the dynamics of GFP-exosome movement. Our model is expected to enhance understanding of the roles of exosome in GBA.
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Affiliation(s)
- Gwang Myeong Seo
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea.
| | - Hongki Lee
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
| | - Yeon Jae Kang
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea.
| | - Donghyun Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
| | - Jong Hwan Sung
- Department of Chemical Engineering, Hongik University, Seoul, 04066, Republic of Korea.
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2
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Bosch A, Guzman HV, Pérez R. Adsorption-Driven Deformation and Footprints of the RBD Proteins in SARS-CoV-2 Variants on Biological and Inanimate Surfaces. J Chem Inf Model 2024; 64:5977-5990. [PMID: 39083670 PMCID: PMC11323246 DOI: 10.1021/acs.jcim.4c00460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 08/02/2024]
Abstract
Respiratory viruses, carried through airborne microdroplets, frequently adhere to surfaces, including plastics and metals. However, our understanding of the interactions between viruses and materials remains limited, particularly in scenarios involving polarizable surfaces. Here, we investigate the role of the receptor-binding domain (RBD) of the spike protein mutations on the adsorption of SARS-CoV-2 to hydrophobic and hydrophilic surfaces employing molecular simulations. To contextualize our findings, we contrast the interactions on inanimate surfaces with those on native biological interfaces, specifically the angiotensin-converting enzyme 2. Notably, we identify a 2-fold increase in structural deformations for the protein's receptor binding motif (RBM) onto inanimate surfaces, indicative of enhanced shock-absorbing mechanisms. Furthermore, the distribution of adsorbed amino acids (landing footprints) on the inanimate surface reveals a distinct regional asymmetry relative to the biological interface, with roughly half of the adsorbed amino acids arranged in opposite sites. In spite of the H-bonds formed at the hydrophilic substrate, the simulations consistently show a higher number of contacts and interfacial area with the hydrophobic surface, where the wild-type RBD adsorbs more strongly than the Delta or Omicron RBDs. In contrast, the adsorption of Delta and Omicron to hydrophilic surfaces was characterized by a distinctive hopping-pattern. The novel shock-absorbing mechanisms identified in the virus adsorption on inanimate surfaces show the embedded high-deformation capacity of the RBD without losing its secondary structure, which could lead to current experimental strategies in the design of virucidal surfaces.
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Affiliation(s)
- Antonio
M. Bosch
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Horacio V. Guzman
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Department
of Theoretical Physics, Jožef Stefan
Institute, SI-1000 Ljubljana, Slovenia
| | - Rubén Pérez
- Departamento
de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed
Matter Physics Center (IFIMAC), Universidad
Autónoma de Madrid, E-28049 Madrid, Spain
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3
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Rasheed A, Parmar K, Jain S, Chakravortty D, Basu S. Weather-related changes in the dehydration of respiratory droplets on surfaces bolster bacterial endurance. J Colloid Interface Sci 2024; 674:653-662. [PMID: 38950464 DOI: 10.1016/j.jcis.2024.06.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 06/23/2024] [Accepted: 06/27/2024] [Indexed: 07/03/2024]
Abstract
HYPOTHESIS The study shows for the first time a fivefold difference in the survivability of the bacterium Pseudomonas Aeruginosa (PA) in a realistic respiratory fluid droplet on fomites undergoing drying at different environmental conditions. For instance, in 2023, the annual average outdoor relative humidity (RH) and temperature in London (UK) is 71 % and 11 °C, whereas in New Delhi (India), it is 45 % and 26 °C, showing that disease spread from fomites could have a demographic dependence. Respiratory fluid droplet ejections containing pathogens on inanimate surfaces are crucial in disease spread, especially in nosocomial settings. However, the interplay between evaporation dynamics, internal fluid flow and precipitation and their collective influence on the distribution and survivability of pathogens at different environmental conditions are less known. EXPERIMENTS Shadowgraphy imaging is employed to study evaporation, and optical microscopy imaging is used for precipitation dynamics. Micro-particle image velocimetry (MicroPIV) measurements reveal the internal flow dynamics. Confocal imaging of fluorescently labelled PA elucidates the bacterial distribution within the deposits. FINDINGS The study finds that the evaporation rate is drastically impeded during drying at elevated solutal concentrations, particularly at high RH and low temperature conditions. MicroPIV shows reduced internal flow under high RH and low temperature (low evaporation rate) conditions. Evaporation rate influences crystal growth, with delayed efflorescence and extending crystallization times. PA forms denser peripheral arrangements under high evaporation rates and shows a fivefold increase in survivability under low evaporation rates. These findings highlight the critical impact of environmental conditions on pathogen persistence and disease spread from inanimate surfaces.
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Affiliation(s)
- Abdur Rasheed
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore India
| | - Kirti Parmar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore India
| | - Siddhant Jain
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore India; School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala 695551 India.
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore India.
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4
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Longest AK, Rockey NC, Lakdawala SS, Marr LC. Review of factors affecting virus inactivation in aerosols and droplets. J R Soc Interface 2024; 21:18. [PMID: 38920060 DOI: 10.1098/rsif.2024.0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/25/2024] [Indexed: 06/27/2024] Open
Abstract
The inactivation of viruses in aerosol particles (aerosols) and droplets depends on many factors, but the precise mechanisms of inactivation are not known. The system involves complex physical and biochemical interactions. We reviewed the literature to establish current knowledge about these mechanisms and identify knowledge gaps. We identified 168 relevant papers and grouped results by the following factors: virus type and structure, aerosol or droplet size, temperature, relative humidity (RH) and evaporation, chemical composition of the aerosol or droplet, pH and atmospheric composition. These factors influence the dynamic microenvironment surrounding a virion and thus may affect its inactivation. Results indicate that viruses experience biphasic decay as the carrier aerosols or droplets undergo evaporation and equilibrate with the surrounding air, and their final physical state (liquid, semi-solid or solid) depends on RH. Virus stability, RH and temperature are interrelated, but the effects of RH are multifaceted and still not completely understood. Studies on the impact of pH and atmospheric composition on virus stability have raised new questions that require further exploration. The frequent practice of studying virus inactivation in large droplets and culture media may limit our understanding of inactivation mechanisms that are relevant for transmission, so we encourage the use of particles of physiologically relevant size and composition in future research.
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Affiliation(s)
- Alexandra K Longest
- Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, VA, USA
| | - Nicole C Rockey
- Department of Civil and Environmental Engineering, Duke University , Durham, NC, USA
| | - Seema S Lakdawala
- Department of Microbiology and Immunology, Emory University , Atlanta, GA, USA
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, VA, USA
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5
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Thite AG, Kale RD, Panda PK. Development of highly bacterial filtration efficient and antibacterial cellulose acetate/gum rosin composite nanofibers for facemask application. Int J Biol Macromol 2024; 270:132221. [PMID: 38729499 DOI: 10.1016/j.ijbiomac.2024.132221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/30/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024]
Abstract
Cellulose acetate (CA) is a non-toxic, renewable, and biodegradable polymeric material that can be effectively electrospuned into bacterial filtration efficient nanofiber membrane for face mask application. However, its fragile and non-antibacterial nature influenced its scalability. In this context, natural antibacterial gum rosin (GR) additive can be explored. Therefore, the present study aimed to produce a CA/GR composite nanofibers membrane for the finest bacterial filtration, excellent antibacterial moiety, and improved tensile properties for facemask application. Hence, in this work, we have studied the effect of GR concentrations (0-15 g) on the needleless electrospinning behavior and fibers' morphology through rheology, electrical conductivity, and SEM analysis. These analyses revealed that GR significantly affects the fibers' spinning behavior, morphology, and diameter of the produced fibers. Later, ATR-FTIR spectroscopy mapped the functional changes in the produced nanofibers that affirmed the integration of GR with CA polymer. This modification resulted in a 3-fold rise in tensile strength and an 11-fold decline in elongation% in 15 g CA/GR composite nanofibers membrane than the control sample. Furthermore, it has shown 98.79 ± 0.10% bacterial filtration efficiency and ∼ 93 % reduction in Staphylococcus Aureus and Klebsiella Pneumoniae bacterial growth, elucidating a high-efficiency level for potential facemask application.
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Affiliation(s)
- Amol G Thite
- Department of Fibres and Textile Processing Technology, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai 400 019, India; The Bombay Textile Research Association, LBS Marg, Ghatkopar (W), Mumbai 400 086, India
| | - Ravindra D Kale
- Department of Fibres and Textile Processing Technology, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai 400 019, India.
| | - Prasanta K Panda
- The Bombay Textile Research Association, LBS Marg, Ghatkopar (W), Mumbai 400 086, India.
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6
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Hussian S, Mehdi M, Ghaffar A, Lan K, Hu Y, Lin H, Qaisrani MA, Ali S, Lin J, Mehdi R, Ma R. Development of a dual point humidity sensor using POF based on twisted fiber structure. Sci Rep 2024; 14:10735. [PMID: 38730029 PMCID: PMC11087481 DOI: 10.1038/s41598-024-59853-3] [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: 02/16/2024] [Accepted: 04/16/2024] [Indexed: 05/12/2024] Open
Abstract
The humidity has often been measured through a single point sensor. Where, the humidity could be varied at different locations as well as depending on environmental conditions. The present paper developed the dual point humidity measuring sensor by using a polymer optical fiber (POF) based on a single illuminating fiber. The sensor's basic structure is to twist two fibers and bend them at a certain radius. However, the dual point sensor is developed through the cascading of twisted micro bend (TMB-1 and TMB-2). The twisting of fibers couples the light from one fiber to another fiber through the side coupling method. An increase in the humidity level leads to a change in the reflective index, which helps to get variation in coupled light intensity. To measure the humidity, the dual point sensors are placed into the control humidity chamber at two random positions. The power reading variation is significantly linear when the humidity level increases from 30 to 80%. The sensor has a fast response of about 1 s and a recovery time of about 4 s. Furthermore, the chemical coating is applied to improve the sensor's sensitivity. Between 30 and 80% range of humidity, the both sensors of dual point TMB-1 and TMB-2 have appropriate sensitivity and detection limits, which is about 680.8 nW/% and 763.9 nW/% and 1.37% and 1.98%, respectively. To measure the humidity at variable positions, the present dual points humidity sensor is well-stable, easy, and straightforward, which uses a less expensive method.
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Affiliation(s)
- Sadam Hussian
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou, 32400, Zhejiang, China
| | - Mujahid Mehdi
- Faculty of Design, Aror University of Art Architecture Design & Heritage Sindh, Sukkur, 65200, Pakistan
| | - Abdul Ghaffar
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou, 32400, Zhejiang, China
| | - Kun Lan
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou, 32400, Zhejiang, China.
| | - Yanjun Hu
- Taiyuan Institute of Technology, Taiyuan, China
| | - Huan Lin
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou, 32400, Zhejiang, China
| | - Mumtaz A Qaisrani
- School of Mechanical & Materials Engineering, University College Dublin, Dublin, Ireland
| | - Sikandar Ali
- Faculty of Design, Aror University of Art Architecture Design & Heritage Sindh, Sukkur, 65200, Pakistan
| | - Jie Lin
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou, 32400, Zhejiang, China
| | - Rehan Mehdi
- Faculty of Design, Aror University of Art Architecture Design & Heritage Sindh, Sukkur, 65200, Pakistan
| | - Rui Ma
- Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province, College of Mechanical Engineering, Quzhou University, Quzhou, 32400, Zhejiang, China
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7
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Huang J, Wang D, Zhu Y, Yang Z, Yao M, Shi X, An T, Zhang Q, Huang C, Bi X, Li J, Wang Z, Liu Y, Zhu G, Chen S, Hang J, Qiu X, Deng W, Tian H, Zhang T, Chen T, Liu S, Lian X, Chen B, Zhang B, Zhao Y, Wang R, Li H. An overview for monitoring and prediction of pathogenic microorganisms in the atmosphere. FUNDAMENTAL RESEARCH 2024; 4:430-441. [PMID: 38933199 PMCID: PMC11197502 DOI: 10.1016/j.fmre.2023.05.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 04/29/2023] [Accepted: 05/16/2023] [Indexed: 06/28/2024] Open
Abstract
Corona virus disease 2019 (COVID-19) has exerted a profound adverse impact on human health. Studies have demonstrated that aerosol transmission is one of the major transmission routes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pathogenic microorganisms such as SARS-CoV-2 can survive in the air and cause widespread infection among people. Early monitoring of pathogenic microorganism transmission in the atmosphere and accurate epidemic prediction are the frontier guarantee for preventing large-scale epidemic outbreaks. Monitoring of pathogenic microorganisms in the air, especially in densely populated areas, may raise the possibility to detect viruses before people are widely infected and contain the epidemic at an earlier stage. The multi-scale coupled accurate epidemic prediction system can provide support for governments to analyze the epidemic situation, allocate health resources, and formulate epidemic response policies. This review first elaborates on the effects of the atmospheric environment on pathogenic microorganism transmission, which lays a theoretical foundation for the monitoring and prediction of epidemic development. Secondly, the monitoring technique development and the necessity of monitoring pathogenic microorganisms in the atmosphere are summarized and emphasized. Subsequently, this review introduces the major epidemic prediction methods and highlights the significance to realize a multi-scale coupled epidemic prediction system by strengthening the multidisciplinary cooperation of epidemiology, atmospheric sciences, environmental sciences, sociology, demography, etc. By summarizing the achievements and challenges in monitoring and prediction of pathogenic microorganism transmission in the atmosphere, this review proposes suggestions for epidemic response, namely, the establishment of an integrated monitoring and prediction platform for pathogenic microorganism transmission in the atmosphere.
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Affiliation(s)
- Jianping Huang
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Danfeng Wang
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yongguan Zhu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zifeng Yang
- National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, First Affiliated Hospital of Guangzhou Medical University, State Key Laboratory of Respiratory Disease (Guangzhou Medical University), Guangzhou 510230, China
| | - Maosheng Yao
- College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xiaoming Shi
- China CDC Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, Beijing 100021, China
| | - Taicheng An
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Qiang Zhang
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing 100084, China
| | - Cunrui Huang
- Vanke School of Public Health, Tsinghua University, Beijing 100084, China
| | - Xinhui Bi
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Jiang Li
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Zifa Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Yongqin Liu
- Center for Pan-third Pole Environment, Lanzhou University, Lanzhou 730000, China
| | - Guibing Zhu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Siyu Chen
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jian Hang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 510640, China
| | - Xinghua Qiu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, China
| | - Weiwei Deng
- Shenzhen Key Laboratory of Soft Mechanics & Smart Manufacturing and Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Huaiyu Tian
- State Key Laboratory of Remote Sensing Science, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100101, China
| | - Tengfei Zhang
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tianmu Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xinbo Lian
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Bin Chen
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Beidou Zhang
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yingjie Zhao
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Rui Wang
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
| | - Han Li
- Collaborative Innovation Center for Western Ecological Safety, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
- College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
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8
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Mofidfar M, Mehrgardi MA, Xia Y, Zare RN. Dependence on relative humidity in the formation of reactive oxygen species in water droplets. Proc Natl Acad Sci U S A 2024; 121:e2315940121. [PMID: 38489384 PMCID: PMC10962988 DOI: 10.1073/pnas.2315940121] [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: 09/13/2023] [Accepted: 02/08/2024] [Indexed: 03/17/2024] Open
Abstract
Water microdroplets (7 to 11 µm average diameter, depending on flow rate) are sprayed in a closed chamber at ambient temperature, whose relative humidity (RH) is controlled. The resulting concentration of ROS (reactive oxygen species) formed in the microdroplets, measured by the amount of hydrogen peroxide (H2O2), is determined by nuclear magnetic resonance (NMR) and by spectrofluorimetric assays after the droplets are collected. The results are found to agree closely with one another. In addition, hydrated hydroxyl radical cations (•OH-H3O+) are recorded from the droplets using mass spectrometry and superoxide radical anions (•O2-) and hydroxyl radicals (•OH) by electron paramagnetic resonance spectroscopy. As the RH varies from 15 to 95%, the concentration of H2O2 shows a marked rise by a factor of about 3.5 in going from 15 to 50%, then levels off. By replacing the H2O of the sprayed water with deuterium oxide (D2O) but keeping the gas surrounding droplets with H2O, mass spectrometric analysis of the hydrated hydroxyl radical cations demonstrates that the water in the air plays a dominant role in producing H2O2 and other ROS, which accounts for the variation with RH. As RH increases, the droplet evaporation rate decreases. These two facts help us understand why viruses in droplets both survive better at low RH values, as found in indoor air in the wintertime, and are disinfected more effectively at higher RH values, as found in indoor air in the summertime, thus explaining the recognized seasonality of airborne viral infections.
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Affiliation(s)
| | - Masoud A. Mehrgardi
- Department of Chemistry, Stanford University, Stanford, CA94305
- Department of Chemistry, University of Isfahan, Isfahan81743, Iran
| | - Yu Xia
- Department of Chemistry, Stanford University, Stanford, CA94305
| | - Richard N. Zare
- Department of Chemistry, Stanford University, Stanford, CA94305
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9
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Chen M, Xing Y, Kong J, Wang D, Lu Y. Bubble manipulates the release of viral aerosols in aeration. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132534. [PMID: 37741211 DOI: 10.1016/j.jhazmat.2023.132534] [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: 03/17/2023] [Revised: 07/19/2023] [Accepted: 09/10/2023] [Indexed: 09/25/2023]
Abstract
Bubble bursting is a common phenomenon in many industrial and natural processes, plays an important role in mediating mass transfer across the water-air interface. But the interplay between bubbles and pathogens remains unclear and the mechanisms of virus aerosolization by the bubble properties have not been well studied. The main objective of this study was to evaluate the water-to-air transfer of viruses by bubbles of different sizes. Unlike the dominant view of smaller bubbles less bioaerosols, it was found that the smaller bubbles could generate significantly more viral aerosols regardless of the virus species (Phi6, MS2, PhiX174, and T7), when the Sauter mean bubble diameters were between 0.56 and 1.65 mm under constant aeration flow rate. The mechanism studies denied the possibilities of more aerosols or better dispersion of viruses in the aerosols generated by the smaller bubbles. However, deeper bubbling could transfer more viruses to the air for MS2, PhiX174, and T7. Their concentrations in aerosols were linearly related to the bubbling depth for these non-enveloped viruses, which demonstrates the bubble-scavenging effect as a main mechanism except for the enveloped virus Phi6. Whereas, unlike these three non-enveloped viruses, Phi6 could survive relatively better in the aerosols generated from the smaller bubbles, though the enhancement of aerosolization by the smaller bubbles was much larger than the improvement of survival. Other mechanisms still remain unknown for this enveloped virus. This study suggests that the attempt of decreasing the bubble size in aeration tank of the wastewater treatment plant might significantly increase the solubility of oxygen as well as the risk of viral aerosols.
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Affiliation(s)
- Menghao Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environment Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yingying Xing
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environment Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiayang Kong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environment Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Dongbin Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environment Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China.
| | - Yun Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environment Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China.
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10
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Coleman H, Saylor Perez J, Schwartz DK, Kaar J, Garcea RL, Randolph TW. Effect of mechanical stresses on viral capsid disruption during droplet formation and drying. Colloids Surf B Biointerfaces 2024; 233:113661. [PMID: 38006709 PMCID: PMC10986848 DOI: 10.1016/j.colsurfb.2023.113661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 11/10/2023] [Accepted: 11/19/2023] [Indexed: 11/27/2023]
Abstract
Identification of the mechanisms by which viruses lose activity during droplet formation and drying is of great importance to understanding the spread of infectious diseases by virus-containing respiratory droplets and to developing thermally stable spray dried live or inactivated viral vaccines. In this study, we exposed suspensions of baculovirus, an enveloped virus, to isolated mechanical stresses similar to those experienced during respiratory droplet formation and spray drying: fluid shear forces, osmotic pressure forces, and surface tension forces at interfaces. DNA released from mechanically stressed virions was measured by SYBR Gold staining to quantify viral capsid disruption. Theoretical estimates of the force exerted by fluid shear, osmotic pressures and interfacial tension forces during respiratory droplet formation and spray drying suggest that osmotic and interfacial stresses have greater potential to mechanically destabilize viral capsids than forces associated with shear stresses. Experimental results confirmed that rapid changes in osmotic pressure, such as those associated with drying of virus-containing droplets, caused significant viral capsid disruption, whereas the effect of fluid shear forces was negligible. Surface tension forces were sufficient to provoke DNA release from virions adsorbed at air-water interfaces, but the extent of this disruption was limited by the time required for virions to diffuse to interfaces. These results demonstrate the effect of isolated mechanical stresses on virus particles during droplet formation and drying.
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Affiliation(s)
- Holly Coleman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80303, United States
| | - J Saylor Perez
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80303, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80303, United States
| | - Joel Kaar
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80303, United States
| | - Robert L Garcea
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, CO 80303, United States
| | - Theodore W Randolph
- Department of Chemical and Biological Engineering, University of Colorado Boulder, CO 80303, United States.
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11
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Nikolaou N, Bouwer LM, Dallavalle M, Valizadeh M, Stafoggia M, Peters A, Wolf K, Schneider A. Improved daily estimates of relative humidity at high resolution across Germany: A random forest approach. ENVIRONMENTAL RESEARCH 2023; 238:117173. [PMID: 37734577 DOI: 10.1016/j.envres.2023.117173] [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: 02/08/2023] [Revised: 09/01/2023] [Accepted: 09/17/2023] [Indexed: 09/23/2023]
Abstract
The lack of readily available methods for estimating high-resolution near-surface relative humidity (RH) and the incapability of weather stations to fully capture the spatiotemporal variability can lead to exposure misclassification in studies of environmental epidemiology. We therefore aimed to predict German-wide 1 × 1 km daily mean RH during 2000-2021. RH observations, longitude and latitude, modelled air temperature, precipitation and wind speed as well as remote sensing information on topographic elevation, vegetation, and the true color band composite were incorporated in a Random Forest (RF) model, in addition to date for capturing the temporal variations of the response-explanatory variables relationship. The model achieved high accuracy (R2 = 0.83) and low errors (Root Mean Square Error (RMSE) of 5.07%, Mean Absolute Percentage Error (MAPE) of 5.19% and Mean Percentage Error (MPE) of - 0.53%), calculated via ten-fold cross-validation. A comparison of our RH predictions with measurements from a dense monitoring network in the city of Augsburg, South Germany confirmed the good performance (R2 ≥ 0.86, RMSE ≤ 5.45%, MAPE ≤ 5.59%, MPE ≤ 3.11%). The model displayed high German-wide RH (22y-average of 79.00%) and high spatial variability across the country, exceeding 12% on yearly averages. Our findings indicate that the proposed RF model is suitable for estimating RH for a whole country in high-resolution and provide a reliable RH dataset for epidemiological analyses and other environmental research purposes.
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Affiliation(s)
- Nikolaos Nikolaou
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; Institute for Medical Information Processing, Biometry and Epidemiology (IBE), Faculty of Medicine, LMU Munich, Pettenkofer School of Public Health, Munich, Germany.
| | - Laurens M Bouwer
- Climate Service Center Germany (GERICS), Helmholtz-Zentrum Hereon, Hamburg, Germany.
| | - Marco Dallavalle
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; Institute for Medical Information Processing, Biometry and Epidemiology (IBE), Faculty of Medicine, LMU Munich, Pettenkofer School of Public Health, Munich, Germany.
| | - Mahyar Valizadeh
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Massimo Stafoggia
- Department of Epidemiology, Lazio Regional Health Service - ASL Roma 1, Rome, Italy.
| | - Annette Peters
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; Institute for Medical Information Processing, Biometry and Epidemiology (IBE), Faculty of Medicine, LMU Munich, Pettenkofer School of Public Health, Munich, Germany.
| | - Kathrin Wolf
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Alexandra Schneider
- Institute of Epidemiology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
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12
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Carrazana E, Ruiz-Gil T, Fujiyoshi S, Tanaka D, Noda J, Maruyama F, Jorquera MA. Potential airborne human pathogens: A relevant inhabitant in built environments but not considered in indoor air quality standards. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165879. [PMID: 37517716 DOI: 10.1016/j.scitotenv.2023.165879] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 07/13/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
Potential airborne human pathogens (PAHPs) may be a relevant component of the air microbiome in built environments. Despite that PAHPs can cause infections, particularly in immunosuppressed patients at medical centers, they are scarcely considered in standards of indoor air quality (IAQ) worldwide. Here, we reviewed the current information on microbial aerosols (bacteria, fungal and viruses) and PAHPs in different types of built environments (e.g., medical center, industrial and non-industrial), including the main factors involved in their dispersion, the methodologies used in their study and their associated biological risks. Our analysis identified the human occupancy and ventilation systems as the primary sources of dispersal of microbial aerosols indoors. We also observed temperature and relative humidity as relevant physicochemical factors regulating the dispersion and viability of some PAHPs. Our analysis revealed that some PAHPs can survive and coexist in different environments while other PAHPs are limited or specific for an environment. In relation to the methodologies (conventional or molecular) the nature of PAHPs and sampling type are pivotal. In this context, indoors air-borne viruses are the less studies because their small size, environmental lability, and absence of efficient sampling techniques and universal molecular markers for their study. Finally, it is noteworthy that PAHPs are not commonly considered and included in IAQ standards worldwide, and when they are included, the total abundance is the single parameter considered and biological risks is excluded. Therefore, we propose a revision, design and establishment of public health policies, regulations and IAQ standards, considering the interactions of diverse factors, such as nature of PAHPs, human occupancy and type of built environments where they develop.
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Affiliation(s)
- Elizabeth Carrazana
- Programa de Doctorado en Ciencias Mención Biología Celular y Molecular Aplicada, Universidad de La Frontera, Temuco, Chile; Laboratorio de Ecología Microbiana Aplicada, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - Tay Ruiz-Gil
- Laboratorio de Ecología Microbiana Aplicada, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile; Programa de Doctorado en Ciencias de Recursos Naturales, Universidad de La Frontera, Temuco, Chile
| | - So Fujiyoshi
- Center for Holobiome and Built Environment (CHOBE), Hiroshima University, Japan; Microbial Genomics and Ecology, PHIS, The IDEC institute, Hiroshima University, Hiroshima, Japan
| | - Daisuke Tanaka
- School of Science Academic Assembly, University of Toyama, Toyama, Japan
| | - Jun Noda
- Graduate School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido, Japan
| | - Fumito Maruyama
- Center for Holobiome and Built Environment (CHOBE), Hiroshima University, Japan; Microbial Genomics and Ecology, PHIS, The IDEC institute, Hiroshima University, Hiroshima, Japan
| | - Milko A Jorquera
- Laboratorio de Ecología Microbiana Aplicada, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile; Center for Holobiome and Built Environment (CHOBE), Hiroshima University, Japan; Network for Extreme Environment Research (NEXER), Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Temuco, Chile.
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13
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Bhadola P, Chaudhary V, Markandan K, Talreja RK, Aggarwal S, Nigam K, Tahir M, Kaushik A, Rustagi S, Khalid M. Analysing role of airborne particulate matter in abetting SARS-CoV-2 outbreak for scheming regional pandemic regulatory modalities. ENVIRONMENTAL RESEARCH 2023; 236:116646. [PMID: 37481054 DOI: 10.1016/j.envres.2023.116646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/04/2023] [Accepted: 07/11/2023] [Indexed: 07/24/2023]
Abstract
The mutating SARS-CoV-2 necessitates gauging the role of airborne particulate matter in the COVID-19 outbreak for designing area-specific regulation modalities based on the environmental state-of-affair. To scheme the protocols, the hotspots of air pollutants such as PM2.5, PM10, NH3, NO, NO2, SO2, and and environmental factors including relative humidity (RH), and temperature, along with COVID-19 cases and mortality from January 2020 till December 2020 from 29 different ground monitoring stations spanning Delhi, are mapped. Spearman correlation coefficients show a positive relationship between SARS-COV-2 with particulate matter (PM2.5 with r > 0.36 and PM10 with r > 0.31 and p-value <0·001). Besides, SARS-COV-2 transmission showed a substantial correlation with NH3 (r = 0.41), NO2 (r = 0.36), and NO (r = 0.35) with a p-value <0.001, which is highly indicative of their role in SARS-CoV-2 transmission. These outcomes are associated with the source of PM and its constituent trace elements to understand their overtone with COVID-19. This strongly validates temporal and spatial variation in COVID-19 dependence on air pollutants as well as on environmental factors. Besides, the bottlenecks of missing latent data, monotonous dependence of variables, and the role air pollutants with secondary environmental variables are discussed. The analysis set the foundation for strategizing regional-based modalities considering environmental variables (i.e., pollutant concentration, relative humidity, temperature) as well as urban and transportation planning for efficient control and handling of future public health emergencies.
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Affiliation(s)
- Pradeep Bhadola
- Centre for Theoretical Physics & Natural Philosophy, Mahidol University, Nakhonsawan 60130, Thailand
| | - Vishal Chaudhary
- Department of Physics, Bhagini Nivedita College, University of Delhi, Delhi 110072, India.
| | - Kalaimani Markandan
- Department of Chemical & Petroleum Engineering, Faculty of Engineering, Technology and Built Environment, UCSI University, Cheras 56000, Kuala Lumpur, Malaysia
| | - Rishi Kumar Talreja
- Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi 110029, India
| | - Sumit Aggarwal
- Division of Epidemiology and Communicable Diseases (ECD), Indian Council of Medical Research (ICMR)-Headquaters, New Delhi 110029, India
| | - Kuldeep Nigam
- Division of Epidemiology and Communicable Diseases (ECD), Indian Council of Medical Research (ICMR)-Headquaters, New Delhi 110029, India
| | - Mohammad Tahir
- Department of Computing, University of Turku, FI-20014, Turun Yliopisto, Finland
| | - Ajeet Kaushik
- NanoBio Tech Laboratory, Department of Environmental Engineering, Florida Polytechnic University, Lakeland, FL, 33805, USA; School of Engineering, University of Petroleum and Energy Studies (UPES), Dehradun, Uttarakhand, India
| | - Sarvesh Rustagi
- School of Applied and Life Sciences, Uttaranchal University, Dehradun, Uttrakhand, India
| | - Mohammad Khalid
- Sunway Centre for Electrochemical Energy and Sustainable Technology (SCEEST), School of Engineering and Technology, Sunway University, No. 5, Jalan University, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia; Division of Research and Development, Lovely Professional University, Phagwara, 144411, Punjab, India; School of Engineering and Technology, Sharda University, Greater Noida, 201310, India.
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14
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Liu Z, Li H, Chu J, Huang Z, Xiao X, Wang Y, He J. The impact of high background particle concentration on the spatiotemporal distribution of Serratia marcescens bioaerosol. JOURNAL OF HAZARDOUS MATERIALS 2023; 458:131863. [PMID: 37354722 DOI: 10.1016/j.jhazmat.2023.131863] [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: 03/10/2023] [Revised: 06/07/2023] [Accepted: 06/13/2023] [Indexed: 06/26/2023]
Abstract
Airborne transmission is a well-established mode of dissemination for infectious diseases, particularly in closed environments. However, previous research has often overlooked the potential impact of background particle concentration on bioaerosol characteristics. We compared the spatial and temporal distributions of bioaerosols under two levels of background particle concentration: heavily polluted (150-250 μg/m3) and excellent (0-35 μg/m3) in a typical ward. Serratia marcescens bioaerosol was adopted as a bioaerosol tracer, and the bioaerosol concentrations were quantified using six-stage Andersen cascade impactors. The results showed a significant reduction (over at least 62.9%) in bioaerosol concentration under heavily polluted levels compared to excellent levels at all sampling points. The temporal analysis also revealed that the decay rate of bioaerosols was higher (at least 0.654 min-1) under heavily polluted levels compared to excellent levels. These findings suggest that background particles can facilitate bioaerosol removal, contradicting the assumption made in previous research that background particle has no effect on bioaerosol characteristics. Furthermore, we observed differences in the size distribution of bioaerosols between the two levels of background particle concentration. The average bioaerosols size under heavily polluted levels was found to be higher than that under excellent levels, and the average particle size under heavily polluted levels gradually increased with time. In conclusion, these results highlight the importance of considering background particle concentration in future research on bioaerosol characteristics.
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Affiliation(s)
- Zhijian Liu
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Haochuan Li
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Jiaqi Chu
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Zhenzhe Huang
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Xia Xiao
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Yongxin Wang
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China
| | - Junzhou He
- School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China.
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15
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Dofuor AK, Quartey NKA, Osabutey AF, Antwi-Agyakwa AK, Asante K, Boateng BO, Ablormeti FK, Lutuf H, Osei-Owusu J, Osei JHN, Ekloh W, Loh SK, Honger JO, Aidoo OF, Ninsin KD. Mango anthracnose disease: the current situation and direction for future research. Front Microbiol 2023; 14:1168203. [PMID: 37692388 PMCID: PMC10484599 DOI: 10.3389/fmicb.2023.1168203] [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: 02/17/2023] [Accepted: 08/03/2023] [Indexed: 09/12/2023] Open
Abstract
Mango anthracnose disease (MAD) is a destructive disease of mangoes, with estimated yield losses of up to 100% in unmanaged plantations. Several strains that constitute Colletotrichum complexes are implicated in MAD worldwide. All mangoes grown for commercial purposes are susceptible, and a resistant cultivar for all strains is not presently available on the market. The infection can widely spread before being detected since the disease is invincible until after a protracted latent period. The detection of multiple strains of the pathogen in Mexico, Brazil, and China has prompted a significant increase in research on the disease. Synthetic pesticide application is the primary management technique used to manage the disease. However, newly observed declines in anthracnose susceptibility to many fungicides highlight the need for more environmentally friendly approaches. Recent progress in understanding the host range, molecular and phenotypic characterization, and susceptibility of the disease in several mango cultivars is discussed in this review. It provides updates on the mode of transmission, infection biology and contemporary management strategies. We suggest an integrated and ecologically sound approach to managing MAD.
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Affiliation(s)
- Aboagye Kwarteng Dofuor
- Department of Biological Sciences, School of Natural and Environmental Sciences, University of Environment and Sustainable Development, Somanya, Ghana
| | - Naa Kwarley-Aba Quartey
- Department of Food Science and Technology, Faculty of Biosciences, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | | | - Kwasi Asante
- Coconut Research Program, Oil Palm Research Institute, Council for Scientific and Industrial Research, Sekondi-Takoradi, Ghana
| | - Belinda Obenewa Boateng
- Coconut Research Program, Oil Palm Research Institute, Council for Scientific and Industrial Research, Sekondi-Takoradi, Ghana
| | - Fred Kormla Ablormeti
- Coconut Research Program, Oil Palm Research Institute, Council for Scientific and Industrial Research, Sekondi-Takoradi, Ghana
| | - Hanif Lutuf
- Crop Protection Division, Oil Palm Research Institute, Council for Scientific and Industrial Research, Kade, Ghana
| | - Jonathan Osei-Owusu
- Department of Physical and Mathematical Sciences, School of Natural and Environmental Sciences, University of Environment and Sustainable Development, Somanya, Ghana
| | - Joseph Harold Nyarko Osei
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - William Ekloh
- Department of Biochemistry, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Seyram Kofi Loh
- Department of Built Environment, School of Sustainable Development, University of Environment and Sustainable Development, Somanya, Ghana
| | - Joseph Okani Honger
- Soil and Irrigation Research Centre, College of Basic and Applied Sciences, School of Agriculture, University of Ghana, Accra, Ghana
| | - Owusu Fordjour Aidoo
- Department of Biological Sciences, School of Natural and Environmental Sciences, University of Environment and Sustainable Development, Somanya, Ghana
| | - Kodwo Dadzie Ninsin
- Department of Biological Sciences, School of Natural and Environmental Sciences, University of Environment and Sustainable Development, Somanya, Ghana
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16
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Norvihoho LK, Yin J, Zhou ZF, Han J, Chen B, Fan LH, Lichtfouse E. Mechanisms controlling the transport and evaporation of human exhaled respiratory droplets containing the severe acute respiratory syndrome coronavirus: a review. ENVIRONMENTAL CHEMISTRY LETTERS 2023; 21:1701-1727. [PMID: 36846189 PMCID: PMC9944801 DOI: 10.1007/s10311-023-01579-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 02/13/2023] [Indexed: 05/24/2023]
Abstract
Transmission of the coronavirus disease 2019 is still ongoing despite mass vaccination, lockdowns, and other drastic measures to control the pandemic. This is due partly to our lack of understanding on the multiphase flow mechanics that control droplet transport and viral transmission dynamics. Various models of droplet evaporation have been reported, yet there is still limited knowledge about the influence of physicochemical parameters on the transport of respiratory droplets carrying the severe acute respiratory syndrome coronavirus 2. Here we review the effects of initial droplet size, environmental conditions, virus mutation, and non-volatile components on droplet evaporation and dispersion, and on virus stability. We present experimental and computational methods to analyze droplet transport, and factors controlling transport and evaporation. Methods include thermal manikins, flow techniques, aerosol-generating techniques, nucleic acid-based assays, antibody-based assays, polymerase chain reaction, loop-mediated isothermal amplification, field-effect transistor-based assay, and discrete and gas-phase modeling. Controlling factors include environmental conditions, turbulence, ventilation, ambient temperature, relative humidity, droplet size distribution, non-volatile components, evaporation and mutation. Current results show that medium-sized droplets, e.g., 50 µm, are sensitive to relative humidity. Medium-sized droplets experience delayed evaporation at high relative humidity, and increase airborne lifetime and travel distance. By contrast, at low relative humidity, medium-sized droplets quickly shrink to droplet nuclei and follow the cough jet. Virus inactivation within a few hours generally occurs at temperatures above 40 °C, and the presence of viral particles in aerosols impedes droplet evaporation.
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Affiliation(s)
- Leslie Kojo Norvihoho
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Jing Yin
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Zhi-Fu Zhou
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Jie Han
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Bin Chen
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
| | - Li-Hong Fan
- The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061 Shaanxi People’s Republic of China
| | - Eric Lichtfouse
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
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17
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Ching WY, Adhikari P, Jawad B, Podgornik R. Towards Quantum-Chemical Level Calculations of SARS-CoV-2 Spike Protein Variants of Concern by First Principles Density Functional Theory. Biomedicines 2023; 11:517. [PMID: 36831053 PMCID: PMC9953097 DOI: 10.3390/biomedicines11020517] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
The spike protein (S-protein) is a crucial part of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with its many domains responsible for binding, fusion, and host cell entry. In this review we use the density functional theory (DFT) calculations to analyze the atomic-scale interactions and investigate the consequences of mutations in S-protein domains. We specifically describe the key amino acids and functions of each domain, which are essential for structural stability as well as recognition and fusion processes with the host cell; in addition, we speculate on how mutations affect these properties. Such unprecedented large-scale ab initio calculations, with up to 5000 atoms in the system, are based on the novel concept of amino acid-amino acid-bond pair unit (AABPU) that allows for an alternative description of proteins, providing valuable information on partial charge, interatomic bonding and hydrogen bond (HB) formation. In general, our results show that the S-protein mutations for different variants foster an increased positive partial charge, alter the interatomic interactions, and disrupt the HB networks. We conclude by outlining a roadmap for future computational research of biomolecular virus-related systems.
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Affiliation(s)
- Wai-Yim Ching
- Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Puja Adhikari
- Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Bahaa Jawad
- Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, MO 64110, USA
- Department of Applied Sciences, University of Technology, Baghdad 10066, Iraq
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute of Theoretical Science, University of Chinese Academy of Sciences, Beijing 100049, China
- CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100090, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325000, China
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18
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Mondal M, Chakrabarti S, Gao YQ, Bhattacharyya D, Chakrabarti J. Microscopic model on indoor propagation of respiratory droplets. Comput Biol Chem 2023; 102:107806. [PMID: 36608615 DOI: 10.1016/j.compbiolchem.2022.107806] [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: 08/19/2022] [Revised: 12/06/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Indoor propagation of airborne diseases is yet poorly understood. Here, we theoretically study a microscopic model based on the motions of virus particles in a respiratory microdroplet, responsible for airborne transmission of diseases, to understand their indoor propagation. The virus particles are driven by a driving force that mimics force due to gushing of air by devices like indoor air conditioning along with the gravity. A viral particle within the droplet experiences viscous drag due to the droplet medium, force due to interfacial tension at the droplet boundary, the thermal forces and mutual interaction forces with the other viral particles. We use Brownian Dynamics (BD) simulations and scaling arguments to study the motion of the droplet, given by that of the center of mass of the viral assembly. The BD simulations show that in presence of the gravity force alone, the time the droplet takes to reach the ground level, defined by the gravitational potential energy being zero, from a vertical height H,tf∼γ-0.1 dependence, where γ is the interfacial tension. In presence of the driving force of magnitude F0 and duration τ0, the horizontal propagation length, Ymax from the source increase linearly with τ0, where the slope is steeper for larger F0. Our scaling analysis explains qualitatively well the simulation observations and show long-distance transmission of airborne respiratory droplets in the indoor conditions due to F0 ∼ nano-dyne.
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Affiliation(s)
- Manas Mondal
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518107, China.
| | - Srabani Chakrabarti
- Department of Physics, Lady Brabourne College, P-1/2, Suhrawardy Avenue, Kolkata 700017, West Bengal, India.
| | - Yi Qin Gao
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518107, China; Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking University, Beijing 100871, China.
| | - Dhananjay Bhattacharyya
- Computational Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
| | - Jaydeb Chakrabarti
- Department of Chemical, Biological and Macro-Molecular Sciences, Thematic unit of Excellence on Computational Materials Science and Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700098, India.
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19
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Gu Z, Han J, Zhang L, Wang H, Luo X, Meng X, Zhang Y, Niu X, Lan Y, Wu S, Cao J, Lichtfouse E. Unanswered questions on the airborne transmission of COVID-19. ENVIRONMENTAL CHEMISTRY LETTERS 2023; 21:725-739. [PMID: 36628267 PMCID: PMC9816530 DOI: 10.1007/s10311-022-01557-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Policies and measures to control pandemics are often failing. While biological factors controlling transmission are usually well explored, little is known about the environmental drivers of transmission and infection. For instance, respiratory droplets and aerosol particles are crucial vectors for the airborne transmission of the severe acute respiratory syndrome coronavirus 2, the causation agent of the coronavirus 2019 pandemic (COVID-19). Once expectorated, respiratory droplets interact with atmospheric particulates that influence the viability and transmission of the novel coronavirus, yet there is little knowledge on this process or its consequences on virus transmission and infection. Here we review the effects of atmospheric particulate properties, vortex zones, and air pollution on virus survivability and transmission. We found that particle size, chemical constituents, electrostatic charges, and the moisture content of airborne particles can have notable effects on virus transmission, with higher survival generally associated with larger particles, yet some viruses are better preserved on small particles. Some chemical constituents and surface-adsorbed chemical species may damage peptide bonds in viral proteins and impair virus stability. Electrostatic charges and water content of atmospheric particulates may affect the adherence of virion particles and possibly their viability. In addition, vortex zones and human thermal plumes are major environmental factors altering the aerodynamics of buoyant particles in air, which can strongly influence the transport of airborne particles and the transmission of associated viruses. Insights into these factors may provide explanations for the widely observed positive correlations between COVID-19 infection and mortality with air pollution, of which particulate matter is a common constituent that may have a central role in the airborne transmission of the novel coronavirus. Supplementary Information The online version contains supplementary material available at 10.1007/s10311-022-01557-z.
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Affiliation(s)
- Zhaolin Gu
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Jie Han
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Liyuan Zhang
- School of Water and Environment, Chang’an University, Xi’an, 710064 People’s Republic of China
| | - Hongliang Wang
- Health Science Center, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Xilian Luo
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Xiangzhao Meng
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Yue Zhang
- School of Architecture, Chang’an University, Xi’an, 710064 People’s Republic of China
| | - Xinyi Niu
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Yang Lan
- School of Public Health, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Shaowei Wu
- School of Public Health, Xi’an Jiaotong University, Xi’an, 710049 People’s Republic of China
| | - Junji Cao
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029 People’s Republic of China
| | - Eric Lichtfouse
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi People’s Republic of China
- CNRS, IRD, INRAE, CEREGE, Aix-Marseille University, 13100, Aix-en-Provence, France
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20
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Negishi N, Yamano R, Hori T, Koura S, Maekawa Y, Sato T. Development of a high-speed bioaerosol elimination system for treatment of indoor air. BUILDING AND ENVIRONMENT 2023; 227:109800. [PMID: 36407015 PMCID: PMC9651995 DOI: 10.1016/j.buildenv.2022.109800] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 06/12/2023]
Abstract
We developed a high-speed filterless airflow multistage photocatalytic elbow aerosol removal system for the treatment of bioaerosols such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human-generated bioaerosols that diffuse into indoor spaces are 1-10 μm in size, and their selective and rapid treatment can reduce the risk of SARS-CoV-2 infection. A high-speed airflow is necessary to treat large volumes of indoor air over a short period. The proposed system can be used to eliminate viruses in aerosols by forcibly depositing aerosols in a high-speed airflow onto a photocatalyst placed inside the system through inertial force and turbulent diffusion. Because the main component of the deposited bioaerosol is water, it evaporates after colliding with the photocatalyst, and the nonvolatile virus remains on the photocatalytic channel wall. The residual virus on the photocatalytic channel wall is mineralized via photocatalytic oxidation with UVA-LED irradiation in the channel. When this system was operated in a 4.5 m3 aerosol chamber, over 99.8% aerosols in the size range of 1-10 μm were removed within 15 min. The system continued delivering such performance with the continuous introduction of aerosols. Because this system exhibits excellent aerosol removal ability at a flow velocity of 5 m/s or higher, it is more suitable than other reactive air purification systems for treating large-volume spaces.
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Key Words
- AOP, advanced oxidation process
- Bioaerosol
- CFD, computational fluid dynamics
- COVID-19, coronavirus disease 2019
- DES, detached eddy simulation
- HEPA, high-efficiency particulate absorbing
- ISO, International Standard Organization
- Indoor air
- LES, Large eddy simulation
- RANS, Reynolds-averaged Navier–Stokes
- SARS-CoV-2
- SARS-CoV-2, severe acute respiratory syndrome coronavirus 2
- SCDLP, soya casein-digested lecithin polysorbate
- TiO2 photocatalyst
- UV, ultraviolet
- UVA, ultraviolet-A
- UVC, ultraviolet-C
- Windspeed
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Affiliation(s)
- Nobuaki Negishi
- Environment Management Research Institute, National Institute of Advanced Industrial Science and Technology, 1-16 Onogawa, Tsukuba, 305-8569, Japan
| | - Ryo Yamano
- Department of Applied Chemistry, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, 275-0016, Japan
| | - Tomoko Hori
- Environment Management Research Institute, National Institute of Advanced Industrial Science and Technology, 1-16 Onogawa, Tsukuba, 305-8569, Japan
| | - Setsuko Koura
- Department of Applied Chemistry, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, 275-0016, Japan
| | - Yuji Maekawa
- Kamaishi Electric Machinery Factory Co. Ltd., 9-171-4 Kasshi-cho, Kamaishi, 026-0055, Japan
| | - Taro Sato
- Kamaishi Electric Machinery Factory Co. Ltd., 9-171-4 Kasshi-cho, Kamaishi, 026-0055, Japan
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21
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Filipić A, Fric K, Ravnikar M, Kogovšek P. Assessment of Different Experimental Setups to Determine Viral Filtration Efficiency of Face Masks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:15353. [PMID: 36430072 PMCID: PMC9690668 DOI: 10.3390/ijerph192215353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Abstract
As a result of the COVID-19 pandemic, many new materials and masks came onto the market. To determine their suitability, several standards specify which properties to test, including bacterial filtration efficiency (BFE), while none describe how to determine viral filtration efficiency (VFE), a property that is particularly important in times of pandemic. Therefore, we focused our research on evaluating the suitability and efficiency of different systems for determining VFE. Here, we evaluated the VFE of 6 mask types (e.g., a surgical mask, a respirator, material for mask production, and cloth masks) with different filtration efficiencies in four experimental setups and compared the results with BFE results. The study included 17 BFE and 22 VFE experiments with 73 and 81 mask samples tested, respectively. We have shown that the masks tested had high VFE (>99% for surgical masks and respirators, ≥98% for material, and 87-97% for cloth masks) and that all experimental setups provided highly reproducible and reliable VFE results (coefficient of variation < 6%). Therefore, the VFE tests described in this study can be integrated into existing standards for mask testing.
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22
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Woodward H, de Kreij RJB, Kruger ES, Fan S, Tiwari A, Hama S, Noel S, Davies Wykes MS, Kumar P, Linden PF. An evaluation of the risk of airborne transmission of COVID-19 on an inter-city train carriage. INDOOR AIR 2022; 32:e13121. [PMID: 36305073 PMCID: PMC9827851 DOI: 10.1111/ina.13121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/02/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Experiments were conducted in an UK inter-city train carriage with the aim of evaluating the risk of infection to the SARS-CoV-2 virus via airborne transmission. The experiments included in-service CO2 measurements and the measurement of salt aerosol concentrations released within the carriage. Computational fluid dynamics simulations of the carriage airflow were also used to visualise the airflow patterns, and the efficacy of the HVAC filter material was tested in a laboratory. Assuming an infectious person is present, the risk of infection for a 1-h train journey was estimated to be 6 times lower than for a full day in a well-ventilated office, or 10-12 times lower than a full day in a poorly ventilated office. While the absolute risk for a typical journey is likely low, in the case where a particularly infectious individual is on-board, there is the potential for a number of secondary infections to occur during a 1-h journey. Every effort should therefore be made to minimize the risk of airborne infection within these carriages. Recommendations are also given for the use of CO2 sensors for the evaluation of the risk of airborne transmission on train carriages.
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Affiliation(s)
- Huw Woodward
- Centre for Environmental PolicyImperial College LondonLondonUK
| | | | - Emily S. Kruger
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical SciencesUniversity of CambridgeCambridgeUK
| | - Shiwei Fan
- Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Arvind Tiwari
- Global Centre for Clean Air Research (GCARE), Department of Civil & Environmental EngineeringUniversity of SurreyGuildfordUK
| | - Sarkawt Hama
- Global Centre for Clean Air Research (GCARE), Department of Civil & Environmental EngineeringUniversity of SurreyGuildfordUK
| | | | | | - Prashant Kumar
- Global Centre for Clean Air Research (GCARE), Department of Civil & Environmental EngineeringUniversity of SurreyGuildfordUK
| | - Paul F. Linden
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical SciencesUniversity of CambridgeCambridgeUK
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23
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Morawska L, Buonanno G, Mikszewski A, Stabile L. The physics of respiratory particle generation, fate in the air, and inhalation. NATURE REVIEWS. PHYSICS 2022; 4:723-734. [PMID: 36065441 PMCID: PMC9430019 DOI: 10.1038/s42254-022-00506-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/03/2022] [Indexed: 05/31/2023]
Abstract
Given that breathing is one of the most fundamental physiological functions, there is an urgent need to broaden our understanding of the fluid dynamics that governs it. There would be many benefits from doing so, including a better assessment of respiratory health, a basis for more precise delivery of pharmaceutical drugs for treatment, and the understanding and potential minimization of respiratory infection transmission. We review the physics of particle generation in the respiratory tract, the fate of these particles in the air on exhalation and the physics of particle inhalation. The main focus is on evidence from experimental studies. We conclude that although there is qualitative understanding of the generation of particles in the respiratory tract, a basic quantitative knowledge of the characteristics of the particles emitted during respiratory activities and their fate after emission, and a theoretical understanding of particle deposition during inhalation, nevertheless the general understanding of the entire process is rudimentary, and many open questions remain.
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Affiliation(s)
- Lidia Morawska
- Queensland University of Technology, International Laboratory for Air Quality & Health (ILAQH), Brisbane, Queensland Australia
- Global Centre for Clean Air Research, Department of Civil and Environmental Engineering, University of Surrey, Guildford, UK
| | - Giorgio Buonanno
- Queensland University of Technology, International Laboratory for Air Quality & Health (ILAQH), Brisbane, Queensland Australia
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy
| | - Alex Mikszewski
- Queensland University of Technology, International Laboratory for Air Quality & Health (ILAQH), Brisbane, Queensland Australia
| | - Luca Stabile
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy
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24
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Prediction of respiratory droplets evolution for safer academic facilities planning amid COVID-19 and future pandemics: A numerical approach. JOURNAL OF BUILDING ENGINEERING 2022; 54:104593. [PMCID: PMC9107331 DOI: 10.1016/j.jobe.2022.104593] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 04/06/2022] [Accepted: 04/27/2022] [Indexed: 05/29/2023]
Abstract
Airborne dispersion of the novel SARS-CoV-2 through the droplets produced during expiratory activities is one of the main transmission mechanisms of this virus from one person to another. Understanding how these droplets spread when infected humans with COVID-19 or other airborne infectious diseases breathe, cough or sneeze is essential for improving prevention strategies in academic facilities. This work aims to assess the transport and fate of droplets in indoor environments using Computational Fluid Dynamics (CFD). This study employs unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations with the Euler-Lagrange approach to visualize the location of thousands of droplets released in a respiratory event and their size evolution. Furthermore, we assess the dispersion of coughing, sneezing, and breathing saliva droplets from an infected source in a classroom with air conditioning and multiple occupants. The results indicate that the suggested social distancing protocol is not enough to avoid the transmission of COVID-19 since small saliva droplets ( ≤ 12 μm) can travel in the streamwise direction up to 4 m when an infected person coughs and more than 7 m when sneezes. These droplets can reach those distances even when there is no airflow from the wind or ventilation systems. The number of airborne droplets in locations close to the respiratory system of a healthy person increases when the relative humidity of the indoor environment is low. This work sets an accurate, rapid, and validated numerical framework reproducible for various indoor environments integrating qualitative and quantitative data analysis of the droplet size evolution of respiratory events for a safer design of physical distancing standards and air cleaning technologies.
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Abstract
The COVID-19 pandemic has significantly affected flight attendants' health, safety, and security. Members of this group work in a densely occupied and enclosed space where social distancing is virtually impossible, compliance with mask rules is uneven, aggressive passenger incidents are at an all-time high, and the vaccination status of passengers on domestic flights is unknown. Here is a description of the response by the federal government and the United States (U.S.) airline industry from the perspective of a flight attendant union between the early days of the COVID-19 pandemic and this writing. Specifically, the issues of ventilation, face masks, aggressive passengers, quarantine and isolation, and vaccinations are reviewed, including actions taken by the executive branch of the U.S. government, regulators, airlines, manufacturers, and our crew member union. Although there will be regional differences around the globe, many of these issues are universal.
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Affiliation(s)
- Judith Anderson
- Air Safety, Health, & Security Department, Association of Flight Attendants, Washington, DC, USA
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26
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Chaudhary V, Bhadola P, Kaushik A, Khalid M, Furukawa H, Khosla A. Assessing temporal correlation in environmental risk factors to design efficient area-specific COVID-19 regulations: Delhi based case study. Sci Rep 2022; 12:12949. [PMID: 35902653 PMCID: PMC9333075 DOI: 10.1038/s41598-022-16781-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 07/15/2022] [Indexed: 12/12/2022] Open
Abstract
Amid ongoing devastation due to Serve-Acute-Respiratory-Coronavirus2 (SARS-CoV-2), the global spatial and temporal variation in the pandemic spread has strongly anticipated the requirement of designing area-specific preventive strategies based on geographic and meteorological state-of-affairs. Epidemiological and regression models have strongly projected particulate matter (PM) as leading environmental-risk factor for the COVID-19 outbreak. Understanding the role of secondary environmental-factors like ammonia (NH3) and relative humidity (RH), latency of missing data structuring, monotonous correlation remains obstacles to scheme conclusive outcomes. We mapped hotspots of airborne PM2.5, PM10, NH3, and RH concentrations, and COVID-19 cases and mortalities for January, 2021-July,2021 from combined data of 17 ground-monitoring stations across Delhi. Spearmen and Pearson coefficient correlation show strong association (p-value < 0.001) of COVID-19 cases and mortalities with PM2.5 (r > 0.60) and PM10 (r > 0.40), respectively. Interestingly, the COVID-19 spread shows significant dependence on RH (r > 0.5) and NH3 (r = 0.4), anticipating their potential role in SARS-CoV-2 outbreak. We found systematic lockdown as a successful measure in combatting SARS-CoV-2 outbreak. These outcomes strongly demonstrate regional and temporal differences in COVID-19 severity with environmental-risk factors. The study lays the groundwork for designing and implementing regulatory strategies, and proper urban and transportation planning based on area-specific environmental conditions to control future infectious public health emergencies.
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Affiliation(s)
- Vishal Chaudhary
- Research Cell and Department of Physics, Bhagini Nivedita College, University of Delhi, New Delhi, 110043, India.
| | - Pradeep Bhadola
- Centre for Theoretical Physics and Natural Philosophy, Nakhonsawan Studiorum for Advanced Studies, Mahidol University, Nakhonsawan, 60130, Thailand.
| | - Ajeet Kaushik
- NanoBioTech Laboratory, Health System Engineering, Department of Environmental Engineering, Florida Polytechnic University, Lakeland, FL, 33805, USA
- School of Engineering, University of Petroleum and Energy Studies (UPES) , Dehradun, Uttarakhand, India
| | - Mohammad Khalid
- Graphene and Advanced 2D Materials Research Group (GAMRG), School of Engineering and Technology, Sunway University, No. 5, Jalan University, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia
- Sunway Materials Smart Science & Engineering (SMS2E) Research Cluster, Sunway University, No. 5, Jalan Universiti, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia
| | - Hidemitsu Furukawa
- Department of Mechanical Systems Engineering, Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata, 992-8510, Japan
| | - Ajit Khosla
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710126, People's Republic of China.
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27
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Rodriguez J, Price O, Jennings R, Creel A, Eaton S, Chesnutt J, McClellan G, Batni SR. A Novel Framework for Modeling Person-to-Person Transmission of Respiratory Diseases. Viruses 2022; 14:1567. [PMID: 35891547 PMCID: PMC9322782 DOI: 10.3390/v14071567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/27/2022] [Accepted: 07/08/2022] [Indexed: 11/16/2022] Open
Abstract
From the beginning of the COVID-19 pandemic, researchers assessed the impact of the disease in terms of loss of life, medical load, economic damage, and other key metrics of resiliency and consequence mitigation; these studies sought to parametrize the critical components of a disease transmission model and the resulting analyses were informative but often lacked critical parameters or a discussion of parameter sensitivities. Using SARS-CoV-2 as a case study, we present a robust modeling framework that considers disease transmissibility from the source through transport and dispersion and infectivity. The framework is designed to work across a range of particle sizes and estimate the generation rate, environmental fate, deposited dose, and infection, allowing for end-to-end analysis that can be transitioned to individual and population health models. In this paper, we perform sensitivity analysis on the model framework to demonstrate how it can be used to advance and prioritize research efforts by highlighting critical parameters for further analyses.
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Affiliation(s)
- Jason Rodriguez
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Owen Price
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Rachel Jennings
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Amy Creel
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Sarah Eaton
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Jennifer Chesnutt
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Gene McClellan
- Applied Research Associates, Inc. (ARA), 4300 San Mateo Blvd NE, Suite A220, Albuquerque, NM 87110, USA; (J.R.); (O.P.); (R.J.); (A.C.); (S.E.); (J.C.); (G.M.)
| | - Sweta R. Batni
- Defense Threat Reduction Agency (DTRA), 8725 John J. Kingman Road #6201, Fort Belvoir, VA 22060, USA
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28
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Ahlawat A, Mishra SK, Herrmann H, Rajeev P, Gupta T, Goel V, Sun Y, Wiedensohler A. Impact of Chemical Properties of Human Respiratory Droplets and Aerosol Particles on Airborne Viruses' Viability and Indoor Transmission. Viruses 2022; 14:v14071497. [PMID: 35891477 PMCID: PMC9318922 DOI: 10.3390/v14071497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/01/2022] [Accepted: 07/01/2022] [Indexed: 02/04/2023] Open
Abstract
The airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as a potential pandemic challenge, especially in poorly ventilated indoor environments, such as certain hospitals, schools, public buildings, and transports. The impacts of meteorological parameters (temperature and humidity) and physical property (droplet size) on the airborne transmission of coronavirus in indoor settings have been previously investigated. However, the impacts of chemical properties of viral droplets and aerosol particles (i.e., chemical composition and acidity (pH)) on viability and indoor transmission of coronavirus remain largely unknown. Recent studies suggest high organic content (proteins) in viral droplets and aerosol particles supports prolonged survival of the virus by forming a glassy gel-type structure that restricts the virus inactivation process under low relative humidity (RH). In addition, the virus survival was found at neutral pH, and inactivation was observed to be best at low (<5) and high pH (>10) values (enveloped bacteriophage Phi6). Due to limited available information, this article illustrates an urgent need to research the impact of chemical properties of exhaled viral particles on virus viability. This will improve our fundamental understanding of indoor viral airborne transmission mechanisms.
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Affiliation(s)
- Ajit Ahlawat
- Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany; (H.H.); (A.W.)
- Correspondence:
| | | | - Hartmut Herrmann
- Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany; (H.H.); (A.W.)
| | - Pradhi Rajeev
- Department of Civil Engineering, Indian Institute of Technology (IIT), Kanpur 208016, India; (P.R.); (T.G.)
| | - Tarun Gupta
- Department of Civil Engineering, Indian Institute of Technology (IIT), Kanpur 208016, India; (P.R.); (T.G.)
| | - Vikas Goel
- School of Interdisciplinary Research, Indian Institute of Technology (IIT), Delhi 110016, India;
| | - Yele Sun
- LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100017, China;
| | - Alfred Wiedensohler
- Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany; (H.H.); (A.W.)
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29
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Aganovic A, Bi Y, Cao G, Kurnitski J, Wargocki P. Modeling the impact of indoor relative humidity on the infection risk of five respiratory airborne viruses. Sci Rep 2022; 12:11481. [PMID: 35798789 PMCID: PMC9261129 DOI: 10.1038/s41598-022-15703-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 06/28/2022] [Indexed: 11/09/2022] Open
Abstract
With a modified version of the Wells-Riley model, we simulated the size distribution and dynamics of five airborne viruses (measles, influenza, SARS-CoV-2, human rhinovirus, and adenovirus) emitted from a speaking person in a typical residential setting over a relative humidity (RH) range of 20-80% and air temperature of 20-25 °C. Besides the size transformation of virus-containing droplets due to evaporation, respiratory absorption, and then removal by gravitational settling, the modified model also considered the removal mechanism by ventilation. The trend and magnitude of RH impact depended on the respiratory virus. For rhinovirus and adenovirus humidifying the indoor air from 20/30 to 50% will be increasing the relative infection risk, however, this relative infection risk increase will be negligible for rhinovirus and weak for adenovirus. Humidification will have a potential benefit in decreasing the infection risk only for influenza when there is a large infection risk decrease for humidifying from 20 to 50%. Regardless of the dry solution composition, humidification will overall increase the infection risk via long-range airborne transmission of SARS-CoV-2. Compared to humidification at a constant ventilation rate, increasing the ventilation rate to moderate levels 0.5 → 2.0 h-1 will have a more beneficial infection risk decrease for all viruses except for influenza. Increasing the ventilation rate from low values of 0.5 h-1 to higher levels of 6 h-1 will have a dominating effect on reducing the infection risk regardless of virus type.
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Affiliation(s)
- Amar Aganovic
- Department of Automation and Process Engineering, The Arctic University of Norway-UiT, 9019, Tromsø, Norway.
| | - Yang Bi
- Department of Energy and Process Engineering, Norwegian University of Science and Technology-NTNU, 7491, Trondheim, Norway
| | - Guangyu Cao
- Department of Energy and Process Engineering, Norwegian University of Science and Technology-NTNU, 7491, Trondheim, Norway
| | - Jarek Kurnitski
- REHVA Technology and Research Committee, Tallinn University of Technology, 19086, Tallinn, Estonia
| | - Pawel Wargocki
- Department of Civil Engineering, Technical University of Denmark, 2800, Copenhagen, Kgs, Denmark
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30
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A Review on Building Design as a Biomedical System for Preventing COVID-19 Pandemic. BUILDINGS 2022. [DOI: 10.3390/buildings12050582] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Sustainable design methods aim to obtain architectural solutions that assure the coexistence and welfare of human beings, inorganic structures, and living things that constitute ecosystems. The novel coronavirus emergence, inadequate vaccines against the present severe acute respiratory syndrome-coronavirus-(SARS-CoV-2), and increases in microbial resistance have made it essential to review the preventative approaches used during pre-antibiotic periods. Apart from low carbon emissions and energy, sustainable architecture for facilities, building designs, and digital modeling should incorporate design approaches to confront the impacts of communicable infections. This review aims to determine how architectural design can protect people and employees from harm; it models viewpoints to highlight the architects’ roles in combating coronavirus disease 2019 (COVID-19) and designing guidelines as a biomedical system for policymakers. The goals include exploring the hospital architecture evolution and the connection between architectural space and communicable infections and recommending design and digital modeling strategies to improve infection prevention and controls. Based on a wide-ranging literature review, it was found that design methods have often played important roles in the prevention and control of infectious diseases and could be a solution for combating the wide spread of the novel coronavirus or coronavirus variants or delta.
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31
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Agrawal A, Gopu M, Mukherjee R, Mampallil D. Microfluidic Droplet Cluster with Distributed Evaporation Rates as a Model for Bioaerosols. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4567-4577. [PMID: 35394793 DOI: 10.1021/acs.langmuir.1c03273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Aerosols and microdroplets are known to act as carriers for pathogens or vessels for chemical reactions. The natural occurrence of evaporation of these droplets has implications for the viability of pathogens or chemical processes. For example, it is important to understand how pathogens survive extreme physiochemical conditions such as confinement and osmotic stress induced by evaporation of aerosol droplets. Previously, larger evaporating droplets were proposed as model systems as the processes in the tiny aerosol droplets are difficult to image. In this context, we propose the concept of evaporation of capillary-clustered aqueous microdroplets dispersed in a thin oil layer. The configuration produces spatially segregated evaporation rates. It allows comparing the consequences of evaporation and its rate for processes occurring in droplets. As a proof of concept, we study the consequences of evaporation and its rate using Escherichia coli (E. coli) and Bacillus subtilis as model organisms. Our experiments indicate that the rate of evaporation of microdroplets is an important parameter in deciding the viability of contained microorganisms. With slow evaporation, E. coli could mitigate the osmotic stress by K+ ion uptake. Our method may also be applicable to other evaporating droplet systems, for example, microdroplet chemistry to understand the implications of evaporation rates.
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Affiliation(s)
- Akanksha Agrawal
- Indian Institute of Science Education and Research Tirupati, Mangalam P.O. PIN 517507 Tirupati, Andhra Pradesh, India
| | - Maheshwar Gopu
- Indian Institute of Science Education and Research Tirupati, Mangalam P.O. PIN 517507 Tirupati, Andhra Pradesh, India
| | - Raju Mukherjee
- Indian Institute of Science Education and Research Tirupati, Mangalam P.O. PIN 517507 Tirupati, Andhra Pradesh, India
| | - Dileep Mampallil
- Indian Institute of Science Education and Research Tirupati, Mangalam P.O. PIN 517507 Tirupati, Andhra Pradesh, India
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Ugarte-Anero A, Fernandez-Gamiz U, Portal-Porras K, Zulueta E, Urbina-Garcia O. Computational characterization of the behavior of a saliva droplet in a social environment. Sci Rep 2022; 12:6405. [PMID: 35437309 PMCID: PMC9016067 DOI: 10.1038/s41598-022-10180-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/04/2022] [Indexed: 11/21/2022] Open
Abstract
The conduct of respiratory droplets is the basis of the study to reduce the spread of a virus in society. The pandemic suffered in early 2020 due to COVID-19 shows the lack of research on the evaporation and fate of droplets exhaled in the environment. The current study, attempts to provide solution through computational fluid dynamics techniques based on a multiphase state with the help of Eulerian-Lagrangian techniques to the activity of respiratory droplets. A numerical study has shown how the behavior of droplets of pure water exhaled in the environment after a sneeze or cough have a dynamic equal to the experimental curve of Wells. The droplets of saliva have been introduced as a saline solution. Considering the mass transferred and the turbulence created, the results has showed that the ambient temperature and relative humidity are parameters that significantly affect the evaporation process, and therefore to the fate. Evaporation time tends to be of a higher value when the temperature affecting the environment is lower. With constant parameters of particle diameter and ambient temperature, an increase in relative humidity increases the evaporation time. A larger particle diameter is consequently transported at a greater distance, since the opposite force it affects is the weight. Finally, a neural network-based model is presented to predict particle evaporation time.
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Affiliation(s)
- Ainara Ugarte-Anero
- Nuclear Engineering and Fluid Mechanics Department, University of the Basque Country, UPV/EHU, Nieves Cano 12, 01006, Vitoria-Gasteiz, Araba, Spain
| | - Unai Fernandez-Gamiz
- Nuclear Engineering and Fluid Mechanics Department, University of the Basque Country, UPV/EHU, Nieves Cano 12, 01006, Vitoria-Gasteiz, Araba, Spain.
| | - Koldo Portal-Porras
- Nuclear Engineering and Fluid Mechanics Department, University of the Basque Country, UPV/EHU, Nieves Cano 12, 01006, Vitoria-Gasteiz, Araba, Spain
| | - Ekaitz Zulueta
- System Engineering and Automation Control Department, University of the Basque Country, UPV/EHU, Nieves Cano 12, 01006, Vitoria-Gasteiz, Araba, Spain
| | - Oskar Urbina-Garcia
- Nuclear Engineering and Fluid Mechanics Department, University of the Basque Country, UPV/EHU, Nieves Cano 12, 01006, Vitoria-Gasteiz, Araba, Spain
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Investigation on the evaporation and dispersion of human respiratory droplets with COVID-19 virus. INTERNATIONAL JOURNAL OF MULTIPHASE FLOW 2022; 147. [PMCID: PMC8603237 DOI: 10.1016/j.ijmultiphaseflow.2021.103904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
On March 11, 2020, COVID-19 was declared as a pandemic by World Health Organization (WHO). Effective prevention is indispensable for defeating the ongoing COVID-19 pandemic. The evaporation and diffusion characteristics of the droplet in the air are the critical factors for the virus transmission by droplets. To better understand transmission routes of COVID-19 through respiratory droplets, a new evaporation and dispersion model for respiratory droplets is proposed to estimate droplet lifetime and the size of spreading zone in air. The importance of respiratory activities and environmental factors on the transmission of respiratory viruses are further discussed. The predictive results demonstrate initial particle size, ambient temperature and relative humidity all have significant effect on the survival time and infection distance of respiratory droplets. Decreasing droplet initial size always shortens the lifetime and the transmission distance of respiratory droplets. The 100 μm droplets expelled by talking or coughing can be carried more than 2 m away. Increasing ambient temperature and decreasing ambient humidity can effectively reduce the lifetime and propagation distance of respiratory droplets, thus reducing the risk of viral infection. These findings could contribute to developing effective prevention measures for controlling infectious disease transmission via droplets.
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Mirzaei PA, Moshfeghi M, Motamedi H, Sheikhnejad Y, Bordbar H. A simplified tempo-spatial model to predict airborne pathogen release risk in enclosed spaces: An Eulerian-Lagrangian CFD approach. BUILDING AND ENVIRONMENT 2022; 207:108428. [PMID: 34658495 PMCID: PMC8511599 DOI: 10.1016/j.buildenv.2021.108428] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 05/19/2023]
Abstract
COVID19 pathogens are primarily transmitted via airborne respiratory droplets expelled from infected bio-sources. However, there is a lack of simplified accurate source models that can represent the airborne release to be utilized in the safe-social distancing measures and ventilation design of buildings. Although computational fluid dynamics (CFD) can provide accurate models of airborne disease transmissions, they are computationally expensive. Thus, this study proposes an innovative framework that benefits from a series of relatively accurate CFD simulations to first generate a dataset of respiratory events and then to develop a simplified source model. The dataset has been generated based on key clinical parameters (i.e., the velocity of droplet release) and environmental factors (i.e., room temperature and relative humidity) in the droplet release modes. An Eulerian CFD model is first validated against experimental data and then interlinked with a Lagrangian CFD model to simulate trajectory and evaporation of numerous droplets in various sizes (0.1 μm-700 μm). A risk assessment model previously developed by the authors is then applied to the simulation cases to identify the horizontal and vertical spread lengths (risk cloud) of viruses in each case within an exposure time. Eventually, an artificial neural network-based model is fitted to the spread lengths to develop the simplified predictive source model. The results identify three main regimes of risk clouds, which can be fairly predicted by the ANN model.
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Affiliation(s)
- P A Mirzaei
- Architecture & Built Environment Department, University of Nottingham, University Park, Nottingham, UK
| | - M Moshfeghi
- Department of Mechanical Engineering, Sogang University, Seoul, South Korea
| | - H Motamedi
- Department of Mechanical Engineering, Tarbiat Modares University, Iran
| | - Y Sheikhnejad
- Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, Universidade de Aveiro, 3810-193, Aveiro, Portugal
- PICadvanced SA, Creative Science Park, Via do Conhecimento, Ed. Central, 3830-352, Ílhavo, Portugal
| | - H Bordbar
- School of Engineering, Aalto University, Finland
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Zhu H, Lai J, Liu B, Wen Z, Xiong Y, Li H, Zhou Y, Fu Q, Yu G, Yan X, Yang X, Zhang J, Wang C, Zeng H. Automatic pulmonary auscultation grading diagnosis of Coronavirus Disease 2019 in China with artificial intelligence algorithms: A cohort study. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 213:106500. [PMID: 34768234 PMCID: PMC8550891 DOI: 10.1016/j.cmpb.2021.106500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 10/20/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Research on automatic auscultation diagnosis of COVID-19 has not yet been developed. We therefore aimed to engineer a deep learning approach for the automated grading diagnosis of COVID-19 by pulmonary auscultation analysis. METHODS 172 confirmed cases of COVID-19 in Tongji Hospital were divided into moderate, severe and critical group. Pulmonary auscultation were recorded in 6-10 sites per patient through 3M littmann stethoscope and the data were transferred to computer to construct the dataset. Convolutional neural network (CNN) were designed to generate classifications of the auscultation. F1 score, the area under the curve (AUC) of the receiver operating characteristic curve, sensitivity and specificity were quantified. Another 45 normal patients were served as control group. RESULTS There are about 56.52%, 59.46% and 78.85% abnormal auscultation in the moderate, severe and critical groups respectively. The model showed promising performance with an averaged F1 scores (0.9938 95% CI 0.9923-0.9952), AUC ROC score (0.9999 95% CI 0.9998-1.0000), sensitivity (0.9938 95% CI 0.9910-0.9965) and specificity (0.9979 95% CI 0.9970-0.9988) in identifying the COVID-19 patients among normal, moderate, severe and critical group. It is capable in identifying crackles, wheezes, phlegm sounds with an averaged F1 scores (0.9475 95% CI 0.9440-0.9508), AUC ROC score (0.9762 95% CI 0.9848-0.9865), sensitivity (0.9482 95% CI 0.9393-0.9578) and specificity (0.9835 95% CI 0.9806-0.9863). CONCLUSIONS Our model is accurate and efficient in automatically diagnosing COVID-19 according to different categories, laying a promising foundation for AI-enabled auscultation diagnosing systems for lung diseases in clinical applications.
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Affiliation(s)
- Hongling Zhu
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Jinsheng Lai
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Bingqiang Liu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Wuhan National Laboratory of Optoelectronics, Wuhan, Hubei 430074, China
| | - Ziyuan Wen
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Wuhan National Laboratory of Optoelectronics, Wuhan, Hubei 430074, China
| | - Yulong Xiong
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Honglin Li
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Yuhua Zhou
- Department of Cardiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Rui Jin Road II, Shanghai, 200025, China
| | - Qiuyun Fu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Wuhan National Laboratory of Optoelectronics, Wuhan, Hubei 430074, China
| | - Guoyi Yu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Wuhan National Laboratory of Optoelectronics, Wuhan, Hubei 430074, China
| | - Xiaoxiang Yan
- Department of Cardiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Rui Jin Road II, Shanghai, 200025, China
| | - Xiaoyun Yang
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Jianmin Zhang
- School of Artificial Intelligence, Jianghan University, Wuhan, Hubei 430056, China
| | - Chao Wang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China; Wuhan National Laboratory of Optoelectronics, Wuhan, Hubei 430074, China.
| | - Hesong Zeng
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
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Davidse A, Zare RN. Effect of Relative Humidity in Air on the Transmission of Respiratory Viruses. MOLECULAR FRONTIERS JOURNAL 2021. [DOI: 10.1142/s252973252140006x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Viral respiratory infections have plagued mankind over its known history. Unfortunately, there has been a lack of meaningful progress in preventing the spread of viral respiratory infections globally. The central dogma appears to be that viruses are the villains. This framing focuses on a viral load balance (VLB) in the air. It follows that physical dilution through various means have been the primary focus of attempts to reduce the spread of infections. The problem of obesity provides a good example of how paradigm blindness can slow down progress in a field. Obesity has been framed as an energy balance disorder that blames overeating and lack of exercise for weight gain. Reframing obesity as a disorder of fat metabolism and storage caused by the quantity and quality of carbohydrates in the diet, referred to as the carbohydrate-insulin model (CIM), opened an alternative line of questioning with a testable hypothesis. Similarly, we postulate an alternative way to frame the spread of viral respiratory infections that would lead to new insights and potentially new ways to prevent infections. It has long been recognized that viral respiratory infections show a pronounced seasonal variation, referred to as seasonal forging, such that they increase in the winter but decrease or virtually disappear in the summer. In temperate regions, people spend over 90% of their time indoors. This is, therefore, where most respiratory infections are expected to occur. Evidence has been accumulating for decades on the strong correlation between variations in indoor relative humidity (RH) and variations in infection rates. Within a RH Goldilocks zone of 40%-60%, encapsulated viruses like influenza and SARS are optimally inactivated outside the infected host. Below 40% and above 80%, viruses can survive for extended periods in the air or on surfaces. This may explain in part the seasonality of infections as the indoor level of RH in winter is typically about 20% and above 40% in summer in temperate regions. However, the mechanism for the inactivation at midrange RH (in summer) is not well understood. This paper offers a hypothesis that could explain these observations. We have demonstrated that H2O2 and other reactive oxygen species (ROS) are formed spontaneously at the water-air interface of pure water microdroplets. Using only water and a nebulizing gas in the presence of oxygen, we have demonstrated the significant disinfectant potential of pure water microdroplets caused by the activity of H2O2 and other ROS. We postulate that spontaneous H2O2 and ROS formation in viruses containing exhaled microdroplets have a similar virucidal effect at mid-range RH. The droplet evaporation rate is sufficient to concentrate the solutes and provide enough time for reactions to occur at significantly higher rates than in bulk solutions. The concentration of H2O2 has also been shown to be positively correlated to RH. In addition, several other ROS/RNS may be present or formed through interactions with H2O2 that may act as even more effective virucide disinfectants to inactivate the virus. Below RH 40% evaporation happens too rapidly for these reactions to make an impact before the droplet is desiccated, and above RH 80% the solutes remain too diluted. Rapid inactivation of viruses at midrange RH may therefore play a greater role in preventing infections than physical dilution of virus load in the air through excessive mechanical ventilation. Similar to obesity, we suggest that a new paradigm that considers virus infectivity outside the host rather than the virus load balance in the air alone could greatly contribute to our understanding of respiratory infections. The proposed new “Relative Humidity Infectivity” RHI paradigm could explain the causal mechanisms underlying seasonal respiratory infections. This can point to better prevention strategies that avoid further distortion of our indoor environment and create conditions within which humans can thrive and be optimally protected. We need more focus on testing the various hypotheses and more data to determine which of the two paradigms will lead us in the right direction or how to use the best of both in an optimal combination. The stakes cannot be higher, and the potential for eradicating future viral respiratory pandemics with nature-based solutions may be right under our noses, literally.
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Affiliation(s)
- Adriaan Davidse
- PO Box 93167 Headon PO, Burlington, Ontario, L7M 4A3, Canada
| | - Richard N. Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305 USA
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Jarvis MC. Drying of virus-containing particles: modelling effects of droplet origin and composition. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2021; 19:1987-1996. [PMID: 34754455 PMCID: PMC8569499 DOI: 10.1007/s40201-021-00750-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/17/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND PURPOSE Virus-containing aerosol droplets emitted by breathing, speech or coughing dry rapidly to equilibrium with ambient relative humidity (RH), increasing in solute concentration with effects on virus survival and decreasing in diameter with effects on sedimentation and respiratory uptake. The aim of this paper is to model the effect of ionic and macromolecular solutes on droplet drying and solute concentration. METHODS Deliquescence-efflorescence concepts and Kohler theory were used to simulate the evolution of solute concentrations and water activity in respiratory droplets, starting from efflorescence data on mixed NaCl/KCl aerosols and osmotic pressure data on respiratory macromolecules. RESULTS In NaCl/KCl solutions total salt concentrations were shown to reach 10-13 M at the efflorescence RH of 40-55%, depending on the K:Na ratio. Dependence on K:Na ratio implies that the evaporation curves differ between aerosols derived from saliva and from airway surfaces. The direct effect of liquid droplet size through the Kelvin term was shown to be smaller and restricted to the evolution of breath emissions. Modelling the effect of proteins and glycoproteins showed that salts determine drying equilibria down to the efflorescence RH, and macromolecules at lower RH. CONCLUSION Differences in solute composition between airway surfaces and saliva are predicted to lead to different drying behaviour of droplets emitted by breathing, speech and coughing. These differences may influence the inactivation of viruses.
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Affiliation(s)
- Michael C. Jarvis
- School of Chemistry, Glasgow University, Glasgow, Scotland G12 8QQ UK
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38
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Influence of ambient conditions on evaporation and transport of respiratory droplets in indoor environment. INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER 2021; 129. [PMCID: PMC8577817 DOI: 10.1016/j.icheatmasstransfer.2021.105750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Respiratory droplets are playing a significant role in the transmission of any flu type disease as well as SARS-Cov-2 virus. The presence of pathogens affects the evaporation of the liquid droplets along with ambient temperature and relative humidity (rh). Complete evaporation of droplets leads to the formation of aerosol or droplet nuclei which remain suspended in the air for a longer period of time and get spread over larger distances increasing the risk of disease transmission. In present work, a droplet evaporation model has been formulated considering the droplet as a salt solution and the formation of crystals has been taken into account which will be analogous to the aerosol formation. After the establishment of the evaporation model, the trajectories of the droplets are investigated considering a turbulent round jet model during exhalation. Aerosols are found to be spreading over distances of 8 to 9 m which is quite alarming. Large droplets get converted to smaller ones but the viral loading of the large droplets is much higher than the smaller as viral loading is proportional to initial size. This is highlighted by the viral load contour and the mean diameter line contour for a half-height window. Different weather conditions are investigated to observe the evaporation of droplets and the formation of aerosols in order to qualitatively analyse the risks associated with each city in specific weather conditions. Hot and dry conditions are most favourable to aerosol formation.
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Aganovic A, Bi Y, Cao G, Drangsholt F, Kurnitski J, Wargocki P. Estimating the impact of indoor relative humidity on SARS-CoV-2 airborne transmission risk using a new modification of the Wells-Riley model. BUILDING AND ENVIRONMENT 2021; 205:108278. [PMID: 34456454 PMCID: PMC8380559 DOI: 10.1016/j.buildenv.2021.108278] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 05/02/2023]
Abstract
A novel modified version of the Wells-Riley model was used to estimate the impact of relative humidity (RH) on the removal of respiratory droplets containing the SARS-CoV-2 virus by deposition through gravitational settling and its inactivation by biological decay; the effect of RH on susceptibility to SARS-CoV-2 was not considered. These effects were compared with the removal achieved by increased ventilation rate with outdoor air. Modeling was performed assuming that the infected person talked continuously for 60 and 120 min. The results of modeling showed that the relative impact of RH on the infection risk depended on the ventilation rate and the size range of virus-laden droplets. A ventilation rate of 0.5 ACH, the change of RH between 20% and 53% was predicted to have a small effect on the infection risk, while at a ventilation rate of 6 ACH this change had nearly no effect. On the contrary, increasing the ventilation rate from 0.5 ACH to 6 ACH was predicted to decrease the infection risk by half which is remarkably larger effect compared with that predicted for RH. It is thus concluded that increasing the ventilation rate is more beneficial for reducing the airborne levels of SARS-CoV-2 than changing indoor RH. PRACTICAL IMPLICATIONS The present results show that humidification to moderate levels of 40%-60% RH should not be expected to provide a significant reduction in infection risk caused by SARS-CoV-2, hence installing and running humidifiers may not be an efficient solution to reduce the risk of COVID-19 disease in indoor spaces. The results do however confirm that ventilation has a key role in controlling SARS-CoV-2 virus concentration in the air providing considerably higher benefits. The modified model developed in the present work can be used by public health experts, engineers, and epidemiologists when selecting different measures to reduce the infection risk from SARS-CoV-2 indoors allowing informed decisions concerning indoor environmental control.
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Affiliation(s)
- Amar Aganovic
- Department of Automation and Process Engineering, UiT The Arctic University of Norway, Tromsø, Norway
| | - Yang Bi
- Department of Energy and Process Engineering, Norwegian University of Science and Technology - NTNU, Trondheim, Norway
| | - Guangyu Cao
- Department of Energy and Process Engineering, Norwegian University of Science and Technology - NTNU, Trondheim, Norway
| | - Finn Drangsholt
- Department of Automation and Process Engineering, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jarek Kurnitski
- REHVA Technology and Research Committee, Tallinn University of Technology, Tallinn, Estonia
| | - Pawel Wargocki
- Department of Civil Engineering, Technical University of Denmark, Copenhagen, Denmark
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Bhardwaj J, Hong S, Jang J, Han CH, Lee J, Jang J. Recent advancements in the measurement of pathogenic airborne viruses. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126574. [PMID: 34252679 PMCID: PMC8256664 DOI: 10.1016/j.jhazmat.2021.126574] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 06/24/2021] [Accepted: 07/02/2021] [Indexed: 05/11/2023]
Abstract
Air-transmissible pathogenic viruses, such as influenza viruses and coronaviruses, are some of the most fatal strains and spread rapidly by air, necessitating quick and stable measurements from sample air volumes to prevent further spread of diseases and to take appropriate steps rapidly. Measurements of airborne viruses generally require their collection into liquids or onto solid surfaces, with subsequent hydrosolization and then analysis using the growth method, nucleic-acid-based techniques, or immunoassays. Measurements can also be performed in real time without sampling, where species-specific determination is generally disabled. In this review, we introduce some recent advancements in the measurement of pathogenic airborne viruses. Air sampling and measurement technologies for viral aerosols are reviewed, with special focus on the effects of air sampling on damage to the sampled viruses and their measurements. Measurement of pathogenic airborne viruses is an interdisciplinary research area that requires understanding of both aerosol technology and biotechnology to effectively address the issues. Hence, this review is expected to provide some useful guidelines regarding appropriate air sampling and virus detection methods for particular applications.
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Affiliation(s)
- Jyoti Bhardwaj
- Sensors and Aerosols Laboratory, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | | | - Junbeom Jang
- Sensors and Aerosols Laboratory, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Chang-Ho Han
- Sensors and Aerosols Laboratory, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaegil Lee
- Sensors and Aerosols Laboratory, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaesung Jang
- Sensors and Aerosols Laboratory, Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea; Department of Biomedical Engineering & Department of Urban and Environmental Engineering, UNIST, Ulsan 44919, Republic of Korea.
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Rezaei M, Netz RR. Water evaporation from solute-containing aerosol droplets: Effects of internal concentration and diffusivity profiles and onset of crust formation. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:091901. [PMID: 34588758 PMCID: PMC8474021 DOI: 10.1063/5.0060080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/18/2021] [Indexed: 05/22/2023]
Abstract
The evaporation of droplets is an important process not only in industrial and scientific applications, but also in the airborne transmission of viruses and other infectious agents. We derive analytical and semi-analytical solutions of the coupled heat and mass diffusion equations within a spherical droplet and in the ambient vapor phase that describe the evaporation process of aqueous free droplets containing nonvolatile solutes. Our results demonstrate that the solute-induced water vapor-pressure reduction considerably slows down the evaporation process and dominates the solute-concentration dependence of the droplet evaporation time. The evaporation-induced enhanced solute concentration near the droplet surface, which is accounted for using a two-stage evaporation description, is found to further slow-down the drying process. On the other hand, the presence of solutes is found to produce a lower limit for the droplet size that can be reached by evaporation and, also, to reduce evaporation cooling of the droplet, which tend to decrease the evaporation time. Overall, the first two effects are dominant, meaning that the droplet evaporation time increases in the presence of solutes. Local variation of the water diffusivity inside the droplet near its surface, which is a consequence of the solute-concentration dependence of the diffusion coefficient, does not significantly change the evaporation time. Crust formation on the droplet surface increases the final equilibrium size of the droplet by producing a hollow spherical particle, the outer radius of which is determined as well.
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Affiliation(s)
| | - Roland R. Netz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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Abstract
AbstractMist is generated by ultrasonic cavitation of water (Fisher Biograde, pH 5.5–6.5) at room temperature (20–25 °C) in open air with nearly constant temperature (22–25 °C) but varying relative humidity (RH; 24–52%) over the course of many months. Water droplets in the mist are initially about 7 μm in diameter at about 50% RH. They are collected, and the concentration of hydrogen peroxide (H2O2) is measured using commercial peroxide test strips and by bromothymol blue oxidation. The quantification method is based on the Fenton chemistry of dye degradation to determine the oxidation capacity of water samples that have been treated by ultrasonication. It is found that the hydrogen peroxide concentration varies nearly linearly with RH over the range studied, reaching a low of 2 parts per million (ppm) at 24% RH and a high of 6 ppm at 52% RH. Some possible public health implications concerning the transmission of respiratory viral infections are suggested for this threefold change in H2O2 concentration with RH.
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Rezaei M, Netz RR. Airborne virus transmission via respiratory droplets: Effects of droplet evaporation and sedimentation. Curr Opin Colloid Interface Sci 2021; 55:101471. [PMID: 34093064 PMCID: PMC8164513 DOI: 10.1016/j.cocis.2021.101471] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Airborne transmission is considered as an important route for the spread of infectious diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and is primarily determined by the droplet sedimentation time, that is, the time droplets spend in air before reaching the ground. Evaporation increases the sedimentation time by reducing the droplet mass. In fact, small droplets can, depending on their solute content, almost completely evaporate during their descent to the ground and remain airborne as so-called droplet nuclei for a long time. Considering that viruses possibly remain infectious in aerosols for hours, droplet nuclei formation can substantially increase the infectious viral air load. Accordingly, the physical-chemical factors that control droplet evaporation and sedimentation times and play important roles in determining the infection risk from airborne respiratory droplets are reviewed in this article.
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Affiliation(s)
- Majid Rezaei
- Fachbereich Physik, Freie Universität Berlin, Berlin, 14195, Germany
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Berlin, 14195, Germany
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Javidpour L, BoŽič A, Naji A, Podgornik R. Electrostatic interactions between the SARS-CoV-2 virus and a charged electret fibre. SOFT MATTER 2021; 17:4296-4303. [PMID: 33908595 DOI: 10.1039/d1sm00232e] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
While almost any kind of face mask offers some protection against particles and pathogens of different sizes, the most efficient ones make use of a layered structure where one or more layers are electrically charged. These electret layers are essential for the efficient filtration of difficult-to-capture small particles, yet the exact nature of electrostatic capture with respect to the charge on both the particles and the electret fibres as well as the effect of the immediate environment remain unclear. Here, we explore in detail the electrostatic interactions between the surface of a single charged electret fibre and a model of the SARS-CoV-2 virus. Using Poisson-Boltzmann electrostatics coupled to a detailed spike protein charge regulation model, we show how pH and salt concentration drastically change both the scale and the sign of the interaction. Furthermore, the configuration of the few spike proteins closest to the electret fibre turns out to be as important for the strength of the interaction as their total number on the virus envelope, a direct consequence of spike protein charge regulation. The results of our work elucidate the details of virus electrostatics and contribute to the general understanding of efficient virus filtration mechanisms.
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Affiliation(s)
- Leili Javidpour
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - AnŽe BoŽič
- Department of Theoretical Physics, JoŽef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Ali Naji
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran and School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran, 19395-5531, Iran
| | - Rudolf Podgornik
- School of Physical Sciences and Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. and Wenzhou Institute of the University of Chinese Academy of Sciences, Wenzhou, Zhejiang 325000, China
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