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Niu Y, Wang F, Luo D, Shu Z, Huang J, Zhang Y, Liu C, Qian H. Vertical transmission of infectious aerosols through building toilet drainage system: An experimental study. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 343:123284. [PMID: 38163630 DOI: 10.1016/j.envpol.2023.123284] [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: 07/06/2023] [Revised: 12/23/2023] [Accepted: 12/30/2023] [Indexed: 01/03/2024]
Abstract
The building's toilet drainage system has been identified as a potential route for the transmission of SARS-CoV-2 during outbreaks. This study employed agar-fluorescein sodium semi-solid as trace particles to investigate the possibility of vertical transmission of the SARS-CoV-2 in drainage system. In both scenarios, where floor drains were all properly sealed or dried out, simulated faeces containing fluorescein sodium were flushed into the toilet bowl. Air sampling was conducted in each restroom, and differential pressure measurements at the floor drain locations were taken. The experimental results showed that when all floor drains were properly sealed, the differential pressure at each floor drain was 0. The fluorescein sodium-traced aerosol did not transmit through the drainage system to various floors, which significantly reduced the risk of infection for users through this route. However, when all floor drains dried out, toilet users above the neutral pressure layer (NPL) were at a high risk of virus infection. Due to the increasing maximum negative pressure at the floor drain above the NPL with ascending floor levels, users on each floor above the NPL faced an elevated infection risk in restrooms. Specifically, users on the top floor were exposed to infectious aerosols roughly 1.6 times that of the first floor above the NPL. Conversely, owing to the increasing maximum positive pressure at the floor drain below the NPL with descending floor levels, users below the NPL experienced a comparatively lower infection risk. This finding has important implications for understanding the vertical transmission dynamics of SARS-CoV-2 in residential or public building and can inform the development of effective control measures.
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Affiliation(s)
- Yuanyuan Niu
- School of Energy and Environment, Southeast University, Nanjing, 210096, China
| | - Fang Wang
- School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Danting Luo
- School of Energy and Environment, Southeast University, Nanjing, 210096, China
| | - Zhiyong Shu
- School of Energy and Environment, Southeast University, Nanjing, 210096, China
| | - Jiayu Huang
- School of Energy and Environment, Southeast University, Nanjing, 210096, China
| | - Yongpeng Zhang
- School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Cong Liu
- School of Energy and Environment, Southeast University, Nanjing, 210096, China
| | - Hua Qian
- School of Energy and Environment, Southeast University, Nanjing, 210096, China.
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2
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Ijaz MK, Sattar SA, Nims RW, Boone SA, McKinney J, Gerba CP. Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization. PeerJ 2023; 11:e16420. [PMID: 38025703 PMCID: PMC10680453 DOI: 10.7717/peerj.16420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.
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Affiliation(s)
- M. Khalid Ijaz
- Global Research & Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, United States of America
| | - Syed A. Sattar
- Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Stephanie A. Boone
- Water & Energy Sustainable Technology Center, University of Arizona, Tucson, AZ, United States of America
| | - Julie McKinney
- Global Research & Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, United States of America
| | - Charles P. Gerba
- Water & Energy Sustainable Technology Center, University of Arizona, Tucson, AZ, United States of America
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3
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Chair SY, Ng ST, Chao CYH, Xu JF. Heating, ventilation, and air-conditioning systems in healthcare: a scoping review. J Hosp Infect 2023; 141:33-40. [PMID: 37640266 DOI: 10.1016/j.jhin.2023.08.012] [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: 02/25/2023] [Revised: 08/09/2023] [Accepted: 08/13/2023] [Indexed: 08/31/2023]
Abstract
Guidelines for heating, ventilation, and air-conditioning systems have been developed for different settings. However, there is a lack of up-to-date evidence providing concrete recommendations for the heating, ventilation, and air-conditioning systems of an isolation room, which is essential to appropriately guide infection control policies. To highlight the guidelines for heating, ventilation, and air-conditioning systems in isolation rooms to inform relevant stakeholders and policymakers. A systematic search was performed based on Joanna Briggs Methodology using five databases (CINAHL, Embase, Joanna Briggs Institute, Medline, and Web of Science) and websites. Eight articles published by government departments were included in this review. Most studies recommended controlled airflow without recirculation, 12 air changes per hour, high-efficiency particulate air filtrate to exhaust contaminated air from the airborne isolation room, humidity ≤60%, and temperature in the range of 18-30 °C. This review provides further evidence that there is a need for interdisciplinary collaborative research to quantify the optimum range for heating, ventilation, and air conditioning system parameters, considering door types, anterooms, and bed management, to effectively reduce the transmission of infection in isolation rooms.
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Affiliation(s)
- S Y Chair
- The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
| | - S T Ng
- Department of Architecture & Civil Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - C Y H Chao
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China; Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - J F Xu
- Department of Architecture & Civil Engineering, City University of Hong Kong, Hong Kong SAR, China
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4
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Abdugheni R, Li L, Yang ZN, Huang Y, Fang BZ, Shurigin V, Mohamad OAA, Liu YH, Li WJ. Microbial Risks Caused by Livestock Excrement: Current Research Status and Prospects. Microorganisms 2023; 11:1897. [PMID: 37630456 PMCID: PMC10456746 DOI: 10.3390/microorganisms11081897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023] Open
Abstract
Livestock excrement is a major pollutant yielded from husbandry and it has been constantly imported into various related environments. Livestock excrement comprises a variety of microorganisms including certain units with health risks and these microorganisms are transferred synchronically during the management and utilization processes of livestock excrement. The livestock excrement microbiome is extensively affecting the microbiome of humans and the relevant environments and it could be altered by related environmental factors as well. The zoonotic microorganisms, extremely zoonotic pathogens, and antibiotic-resistant microorganisms are posing threats to human health and environmental safety. In this review, we highlight the main feature of the microbiome of livestock excrement and elucidate the composition and structure of the repertoire of microbes, how these microbes transfer from different spots, and they then affect the microbiomes of related habitants as a whole. Overall, the environmental problems caused by the microbiome of livestock excrement and the potential risks it may cause are summarized from the microbial perspective and the strategies for prediction, prevention, and management are discussed so as to provide a reference for further studies regarding potential microbial risks of livestock excrement microbes.
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Affiliation(s)
- Rashidin Abdugheni
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
| | - Li Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen-Ni Yang
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yin Huang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bao-Zhu Fang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
| | - Vyacheslav Shurigin
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
| | - Osama Abdalla Abdelshafy Mohamad
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
| | - Yong-Hong Liu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
| | - Wen-Jun Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
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Kwiatkowska A, Granicka LH. Anti-Viral Surfaces in the Fight against the Spread of Coronaviruses. MEMBRANES 2023; 13:membranes13050464. [PMID: 37233525 DOI: 10.3390/membranes13050464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 04/22/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023]
Abstract
This review is conducted against the background of nanotechnology, which provides us with a chance to effectively combat the spread of coronaviruses, and which primarily concerns polyelectrolytes and their usability for obtaining protective function against viruses and as carriers for anti-viral agents, vaccine adjuvants, and, in particular, direct anti-viral activity. This review covers nanomembranes in the form of nano-coatings or nanoparticles built of natural or synthetic polyelectrolytes--either alone or else as nanocomposites for creating an interface with viruses. There are not a wide variety of polyelectrolytes with direct activity against SARS-CoV-2, but materials that are effective in virucidal evaluations against HIV, SARS-CoV, and MERS-CoV are taken into account as potentially active against SARS-CoV-2. Developing new approaches to materials as interfaces with viruses will continue to be relevant in the future.
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Affiliation(s)
- Angelika Kwiatkowska
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks. Trojdena 4 St., 02-109 Warsaw, Poland
| | - Ludomira H Granicka
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks. Trojdena 4 St., 02-109 Warsaw, Poland
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6
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Lyu X, Luo Z, Shao L, Awbi H, Lo Piano S. Safe CO 2 threshold limits for indoor long-range airborne transmission control of COVID-19. BUILDING AND ENVIRONMENT 2023; 234:109967. [PMID: 36597420 PMCID: PMC9801696 DOI: 10.1016/j.buildenv.2022.109967] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/16/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
CO2-based infection risk monitoring is highly recommended during the current COVID-19 pandemic. However, the CO2 monitoring thresholds proposed in the literature are mainly for spaces with fixed occupants. Determining CO2 threshold is challenging in spaces with changing occupancy due to the co-existence of quanta and CO2 remaining from previous occupants. Here, we propose a new calculation framework for deriving safe excess CO2 thresholds (above outdoor level), C t, for various spaces with fixed/changing occupancy and analyze the uncertainty involved. We categorized common indoor spaces into three scenarios based on their occupancy conditions, e.g., fixed or varying infection ratios (infectors/occupants). We proved that the rebreathed fraction-based model can be applied directly for deriving C t in the case of a fixed infection ratio (Scenario 1 and Scenario 2). In the case of varying infection ratios (Scenario 3), C t derivation must follow the general calculation framework due to the existence of initial quanta/excess CO2. Otherwise, C t can be significantly biased (e.g., 260 ppm) when the infection ratio varies greatly. C t can vary significantly based on specific space factors such as occupant number, physical activity, and community prevalence, e.g., 7 ppm for gym and 890 ppm for lecture hall, indicating C t must be determined on a case-by-case basis. An uncertainty of up to 6 orders of magnitude for C t was found for all cases due to uncertainty in emissions of quanta and CO2, thus emphasizing the role of accurate emissions data in determining C t.
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Affiliation(s)
- Xiaowei Lyu
- School of the Built Environment, University of Reading, UK
| | - Zhiwen Luo
- Welsh School of Architecture, Cardiff University, UK
| | - Li Shao
- School of the Built Environment, University of Reading, UK
| | - Hazim Awbi
- School of the Built Environment, University of Reading, UK
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7
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Hwang KS, Seo EU, Choi N, Kim J, Kim HN. 3D engineered tissue models for studying human-specific infectious viral diseases. Bioact Mater 2023; 21:576-594. [PMID: 36204281 PMCID: PMC9519398 DOI: 10.1016/j.bioactmat.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/13/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022] Open
Abstract
Viral infections cause damage to various organ systems by inducing organ-specific symptoms or systemic multi-organ damage. Depending on the infection route and virus type, infectious diseases are classified as respiratory, nervous, immune, digestive, or skin infections. Since these infectious diseases can widely spread in the community and their catastrophic effects are severe, identification of their causative agent and mechanisms underlying their pathogenesis is an urgent necessity. Although infection-associated mechanisms have been studied in two-dimensional (2D) cell culture models and animal models, they have shown limitations in organ-specific or human-associated pathogenesis, and the development of a human-organ-mimetic system is required. Recently, three-dimensional (3D) engineered tissue models, which can present human organ-like physiology in terms of the 3D structure, utilization of human-originated cells, recapitulation of physiological stimuli, and tight cell–cell interactions, were developed. Furthermore, recent studies have shown that these models can recapitulate infection-associated pathologies. In this review, we summarized the recent advances in 3D engineered tissue models that mimic organ-specific viral infections. First, we briefly described the limitations of the current 2D and animal models in recapitulating human-specific viral infection pathology. Next, we provided an overview of recently reported viral infection models, focusing particularly on organ-specific infection pathologies. Finally, a future perspective that must be pursued to reconstitute more human-specific infectious diseases is presented. 3D in vitro models are different from the traditional model in the infection process. Human-specific infection research requires a 3D microenvironment and human cells. 3D in vitro infectious models can be useful for basic research on infectious disease. 3D in vitro infectious models recapitulate the complex cell-virus-immune interaction.
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Affiliation(s)
- Kyeong Seob Hwang
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- School of Mechanical Engineering, Yonsei University, Seoul, 03722, Republic of Korea
| | - Eun U Seo
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Nakwon Choi
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Jongbaeg Kim
- School of Mechanical Engineering, Yonsei University, Seoul, 03722, Republic of Korea
- Corresponding author.
| | - Hong Nam Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- School of Mechanical Engineering, Yonsei University, Seoul, 03722, Republic of Korea
- Yonsei-KIST Convergence Research Institute, Yonsei University, Seoul, 03722, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
- Corresponding author. Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
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8
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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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9
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Chen W, Liu L, Hang J, Li Y. Predominance of inhalation route in short-range transmission of respiratory viruses: Investigation based on computational fluid dynamics. BUILDING SIMULATION 2022; 16:765-780. [PMID: 36575690 PMCID: PMC9782262 DOI: 10.1007/s12273-022-0968-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/19/2022] [Accepted: 11/25/2022] [Indexed: 05/28/2023]
Abstract
During the Coronavirus disease 2019 pandemic, short-range virus transmission has been observed to have a higher risk of causing infection than long-range virus transmission. However, the roles played by the inhalation and large droplet routes cannot be distinguished in practice. A recent analytical study revealed the predominance of short-range inhalation over the large droplet spray route as causes of respiratory infections. In the current study, short-range exposure was analyzed via computational fluid dynamics (CFD) simulations using a discrete phase model. Detailed facial membranes, including eyes, nostrils, and a mouth, were considered. In CFD simulations, there is no need for a spherical approximation of the human head for estimating deposition nor the "anisokinetic aerosol sampling" approximation for estimating inhalation in the analytical model. We considered two scenarios (with two spheres [Scenario 1] and two human manikins [Scenario 2]), source-target distances of 0.2 to 2 m, and droplet diameters of 3 to 1,500 µm. The overall CFD exposure results agree well with data previously obtained from a simple analytical model. The CFD results confirm the predominance of the short-range inhalation route beyond 0.2 m for expiratory droplets smaller than 50 µm during talking and coughing. A critical droplet size of 87.5 µm was found to differentiate droplet behaviors. The number of droplets deposited on the target head exceeded those exposed to facial membranes, which implies a risk of exposure through the immediate surface route over a short range. Electronic Supplementary Material ESM the Supplementary Materials are available in the online version of this article at 10.1007/s12273-022-0968-y.
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Affiliation(s)
- Wenzhao Chen
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Li Liu
- Department of Building Science, Tsinghua University, Beijing, 100084 China
| | - Jian Hang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519082 China
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Faculty of Architecture, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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10
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Avni O, Dagan Y. Dispersion of free-falling saliva droplets by two-dimensional vortical flows. THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS 2022; 36:993-1011. [PMID: 36373071 PMCID: PMC9638496 DOI: 10.1007/s00162-022-00633-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
ABSTRACT The dispersion of respiratory saliva droplets by indoor wake structures may enhance the transmission of various infectious diseases, as the wake spreads virus-laden droplets across the room. Thus, this study analyzes the interaction between vortical wake structures and exhaled multi-component saliva droplets. A self-propelling analytically described dipolar vortex is chosen as a model wake flow, passing through a cloud of micron-sized evaporating saliva droplets. The droplets' spatial location, velocity, diameter, and temperature are traced, coupled to their local flow field. For the first time, the wake structure decay is incorporated and analyzed, which is proved essential for accurately predicting the settling distances of the dispersed droplets. The model also considers the nonvolatile saliva components, adequately capturing the essence of droplet-aerosol transition and predicting the equilibrium diameter of the residual aerosols. Our analytic model reveals non-intuitive interactions between wake flows, droplet relaxation time, gravity, and transport phenomena. We reveal that given the right conditions, a virus-laden saliva droplet might translate to distances two orders of magnitude larger than the carrier-flow characteristic size. Moreover, accounting for the nonvolatile contents inside the droplet may lead to fundamentally different dispersion and settling behavior compared to non-evaporating particles or pure water droplets. Ergo, we suggest that the implementation of more complex evaporation models might be critical in high-fidelity simulations aspiring to assess the spread of airborne respiratory droplets.
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Affiliation(s)
- Orr Avni
- Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, 320003 Haifa, Israel
| | - Yuval Dagan
- Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, 320003 Haifa, Israel
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Zhang S, Niu D, Lin Z. Occupancy-aided ventilation for airborne infection risk control: Continuously or intermittently reduced occupancies? BUILDING SIMULATION 2022; 16:733-747. [PMID: 36373145 PMCID: PMC9638348 DOI: 10.1007/s12273-022-0951-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/24/2022] [Accepted: 10/09/2022] [Indexed: 05/25/2023]
Abstract
Ventilation is an important engineering measure to control the airborne infection risk of acute respiratory diseases, e.g., Corona Virus Disease 2019 (COVID-19). Occupancy-aided ventilation methods can effectively improve the airborne infection risk control performance with a sacrifice of decreasing working productivity because of the reduced occupancy. This study evaluates the effectiveness of two occupancy-aided ventilation methods, i.e., the continuously reduced occupancy method and the intermittently reduced occupancy method. The continuously reduced occupancy method is determined by the steady equation of the mass conservation law of the indoor contaminant, and the intermittently reduced occupancy method is determined by a genetic algorithm-based optimization. A two-scenarios-based evaluation framework is developed, i.e., one with targeted airborne infection risk control performance (indicated by the mean rebreathed fraction) and the other with targeted working productivity (indicated by the accumulated occupancy). The results show that the improvement in the airborne infection risk control performance linearly and quadratically increases with the reduction in the working productivity for the continuously reduced occupancy method and the intermittently reduced occupancy method respectively. At a given targeted airborne infection risk control performance, the intermittently reduced occupancy method outperforms the continuously reduced occupancy method by improving the working productivity by up to 92%. At a given targeted working productivity, the intermittently reduced occupancy method outperforms the continuously reduced occupancy method by improving the airborne infection risk control performance by up to 38%.
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Affiliation(s)
- Sheng Zhang
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Dun Niu
- School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, China
| | - Zhang Lin
- Division of Building Science and Technology, City University of Hong Kong, Hong Kong, China
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12
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Jimenez JL, Marr LC, Randall K, Ewing ET, Tufekci Z, Greenhalgh T, Tellier R, Tang JW, Li Y, Morawska L, Mesiano‐Crookston J, Fisman D, Hegarty O, Dancer SJ, Bluyssen PM, Buonanno G, Loomans MGLC, Bahnfleth WP, Yao M, Sekhar C, Wargocki P, Melikov AK, Prather KA. What were the historical reasons for the resistance to recognizing airborne transmission during the COVID-19 pandemic? INDOOR AIR 2022; 32:e13070. [PMID: 36040283 PMCID: PMC9538841 DOI: 10.1111/ina.13070] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 05/05/2023]
Abstract
The question of whether SARS-CoV-2 is mainly transmitted by droplets or aerosols has been highly controversial. We sought to explain this controversy through a historical analysis of transmission research in other diseases. For most of human history, the dominant paradigm was that many diseases were carried by the air, often over long distances and in a phantasmagorical way. This miasmatic paradigm was challenged in the mid to late 19th century with the rise of germ theory, and as diseases such as cholera, puerperal fever, and malaria were found to actually transmit in other ways. Motivated by his views on the importance of contact/droplet infection, and the resistance he encountered from the remaining influence of miasma theory, prominent public health official Charles Chapin in 1910 helped initiate a successful paradigm shift, deeming airborne transmission most unlikely. This new paradigm became dominant. However, the lack of understanding of aerosols led to systematic errors in the interpretation of research evidence on transmission pathways. For the next five decades, airborne transmission was considered of negligible or minor importance for all major respiratory diseases, until a demonstration of airborne transmission of tuberculosis (which had been mistakenly thought to be transmitted by droplets) in 1962. The contact/droplet paradigm remained dominant, and only a few diseases were widely accepted as airborne before COVID-19: those that were clearly transmitted to people not in the same room. The acceleration of interdisciplinary research inspired by the COVID-19 pandemic has shown that airborne transmission is a major mode of transmission for this disease, and is likely to be significant for many respiratory infectious diseases.
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Affiliation(s)
- Jose L. Jimenez
- Department of Chemistry and Cooperative Institute for Research in Environmental SciencesUniversity of ColoradoBoulderColoradoUSA
| | - Linsey C. Marr
- Department of Civil and Environmental EngineeringVirginia TechBlacksburgVirginiaUSA
| | | | | | - Zeynep Tufekci
- School of JournalismColumbia UniversityNew YorkNew YorkUSA
| | - Trish Greenhalgh
- Department of Primary Care Health SciencesMedical Sciences DivisionUniversity of OxfordOxfordUK
| | | | - Julian W. Tang
- Department of Respiratory SciencesUniversity of LeicesterLeicesterUK
| | - Yuguo Li
- Department of Mechanical EngineeringUniversity of Hong KongHong KongChina
| | - Lidia Morawska
- International Laboratory for Air Quality and HeathQueensland University of TechnologyBrisbaneQueenslandAustralia
| | | | - David Fisman
- Dalla Lana School of Public HealthUniversity of TorontoTorontoOntarioCanada
| | - Orla Hegarty
- School of Architecture, Planning & Environmental PolicyUniversity College DublinDublinIreland
| | - Stephanie J. Dancer
- Department of MicrobiologyHairmyres Hospital, Glasgow, and Edinburgh Napier UniversityGlasgowUK
| | - Philomena M. Bluyssen
- Faculty of Architecture and the Built EnvironmentDelft University of TechnologyDelftThe Netherlands
| | - Giorgio Buonanno
- Department of Civil and Mechanical EngineeringUniversity of Cassino and Southern LazioCassinoItaly
| | - Marcel G. L. C. Loomans
- Department of the Built EnvironmentEindhoven University of Technology (TU/e)EindhovenThe Netherlands
| | - William P. Bahnfleth
- Department of Architectural EngineeringThe Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Maosheng Yao
- College of Environmental Sciences and EngineeringPeking UniversityBeijingChina
| | - Chandra Sekhar
- Department of the Built EnvironmentNational University of SingaporeSingaporeSingapore
| | - Pawel Wargocki
- Department of Civil EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Arsen K. Melikov
- Department of Civil EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Kimberly A. Prather
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCaliforniaUSA
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13
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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:v14071567. [PMID: 35891547 PMCID: PMC9322782 DOI: 10.3390/v14071567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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
- Correspondence:
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14
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Luo Q, Ou C, Hang J, Luo Z, Yang H, Yang X, Zhang X, Li Y, Fan X. Role of pathogen-laden expiratory droplet dispersion and natural ventilation explaining a COVID-19 outbreak in a coach bus. BUILDING AND ENVIRONMENT 2022; 220:109160. [PMID: 35615259 PMCID: PMC9122785 DOI: 10.1016/j.buildenv.2022.109160] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 05/30/2023]
Abstract
The influencing mechanism of droplet transmissions inside crowded and poorly ventilated buses on infection risks of respiratory diseases is still unclear. Based on experiments of one-infecting-seven COVID-19 outbreak with an index patient at bus rear, we conducted CFD simulations to investigate integrated effects of initial droplet diameters(tracer gas, 5 μm, 50 μm and 100 μm), natural air change rates per hour(ACH = 0.62, 2.27 and 5.66 h-1 related to bus speeds) and relative humidity(RH = 35% and 95%) on pathogen-laden droplet dispersion and infection risks. Outdoor pressure difference around bus surfaces introduces natural ventilation airflow entering from bus-rear skylight and leaving from the front one. When ACH = 0.62 h-1(idling state), the 30-min-exposure infection risk(TIR) of tracer gas is 15.3%(bus rear) - 11.1%(bus front), and decreases to 3.1%(bus rear)-1.3%(bus front) under ACH = 5.66 h-1(high bus speed).The TIR of large droplets(i.e., 100 μm/50 μm) is almost independent of ACH, with a peak value(∼3.1%) near the index patient, because over 99.5%/97.0% of droplets deposit locally due to gravity. Moreover, 5 μm droplets can disperse further with the increasing ventilation. However, TIR for 5 μm droplets at ACH = 5.66 h-1 stays relatively small for rear passengers(maximum 0.4%), and is even smaller in the bus middle and front(<0.1%). This study verifies that differing from general rooms, most 5 μm droplets deposit on the route through the long-and-narrow bus space with large-area surfaces(L∼11.4 m). Therefore, tracer gas can only simulate fine droplet with little deposition but cannot replace 5-100 μm droplet dispersion in coach buses.
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Affiliation(s)
- Qiqi Luo
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Cuiyun Ou
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Jian Hang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Zhiwen Luo
- School of the Built Environment, University of Reading, Reading, UK
| | - Hongyu Yang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Xia Yang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Xuelin Zhang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Xiaodan Fan
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
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15
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Ijaz MK, Nims RW, McKinney J. Emerging SARS-CoV-2 Mutational Variants of Concern Should Not Vary in Susceptibility to Microbicidal Actives. Life (Basel) 2022; 12:987. [PMID: 35888077 PMCID: PMC9323193 DOI: 10.3390/life12070987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/20/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023] Open
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is evolving, with emergence of mutational variants due to the error-prone replication process of RNA viruses, in general. More recently, the Delta and Omicron variants (including sub-variants BA.1-5) predominate globally, and a Delta-Omicron recombinant termed Deltacron has emerged. The emergence of variants of concern (VOC) demonstrating immune evasion and potentially greater transmissibility and virulence naturally raises concern in both the infection control communities and the public at large, as to the continued suitability of interventions intended to mitigate the risk of viral dissemination and acquisition of the associated disease COVID-19. We evaluated the virucidal efficacy of targeted surface hygiene products (an ethanol/quaternary ammonium compound (QAC)-containing disinfectant spray, a QAC disinfectant wipe, a lactic acid disinfectant wipe, and a citric acid disinfectant wipe) through both theoretical arguments and empirical testing using international standard methodologies (ASTM E1053-20 hard surface test and EN14476:2013+A2:2019 suspension test) in the presence of soil loads simulating patients' bodily secretions/excretions containing shed virus. The results demonstrate, as expected, complete infectious viral inactivation (≥3.0 to ≥4.7 log10 reduction in infectious virus titer after as little as 15 s contact time at room temperature) by these surface hygiene agents of the original SARS-CoV-2 isolate and its Beta and Delta VOC. Through appropriate practices of targeted surface hygiene, it is expected that irrespective of the SARS-CoV-2 VOC encountered as the current pandemic unfolds (and, for that matter, any emerging and/or re-emerging enveloped virus), the chain of infection from virus-contaminated fomites to the hand and mucous membranes of a susceptible person may be disrupted.
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Affiliation(s)
- M. Khalid Ijaz
- Global Research and Development for Lysol and Dettol, Reckitt Benckiser LLC, One Phillips Drive, Montvale, NJ 07645, USA;
| | | | - Julie McKinney
- Global Research and Development for Lysol and Dettol, Reckitt Benckiser LLC, One Phillips Drive, Montvale, NJ 07645, USA;
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16
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Luo L, Zeng X, Wu Y, An F, Huang J, Yang H, Jiang Q, Ou Q, Du J, Song N. Influencing Factors of Students Aged 10–20 Non-participating in Home Physical Exercise During the COVID-19 Isolation Policy Period: A Cross-Sectional Study From China. Front Public Health 2022; 10:787857. [PMID: 35784228 PMCID: PMC9240655 DOI: 10.3389/fpubh.2022.787857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 05/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background A number of public health measures are required during the COVID-19 pandemic. To stop the spread of COVID-19, the Chinese government has adopted isolation policies, including closing non-essential businesses, public transportation and schools, moving students' face-to-face learning to online, and recommending the cancellation of all non-essential activities and outdoor activities. However, while this isolation strategy has reduced human-to-human transmission of COVID-19, it has led to dramatic changes in students' daily lives and learning styles, including reduced physical activity and increased sedentary time. Considering the potentially harmful effects of physical inactivity, this study hoped to explore the incidence and influencing factors of non-participation in home physical exercise among Chinese students aged 10–20 during the implementation of the COVID-19 isolation policy. Methods Through an online questionnaire platform, this study created an open-ended questionnaire (from March 1, 2020 to March 10, 2020) and distributed it to students in areas where isolation policies were enforced. The questionnaire was initially distributed by 10 recruited volunteers, and then the questionnaire was voluntarily forwarded and shared by the subjects or others, in a “snowball” way, to expand distribution. Finally, the survey data of 4,532 Chinese students aged 10–20 were collected. The incidence of respondents non-participating in home physical activity was determined using univariate analysis. Using odds ratios and 95% confidence intervals of a multivariate binary logistic regression model, factors influencing non-participation in home physical exercise were estimated. Results Among the sample students, the incidence rate of non-participating in home physical exercise was 25.86% (24.06–27.15%). Exercise intentions, exercise habits, self-assessed health, beliefs in physical health, family exercise, family exercise recommendations, home exercise conditions, school exercise guidance, and health education programs had a negative impact on students non-participating in home physical exercise. Academic performance and electronic product use had a positive effect on non-participating in home physical exercise. Conclusions A variety of forward leaning factors, enabling factors and demand factors have affected the occurrence of students” non-participating in home physical exercise. Future health isolation policies should take into account these influencing factors to reduce the occurrence of students” non-participating in home physical exercise and to promote students' independent participation in physical exercise.
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Affiliation(s)
- Lin Luo
- College of Physical Education, Guizhou Normal University, Guiyang, China
- Basic Education Research Center, Southwest University, Chongqing, China
- East China Normal University-Xuhui Postdoctoral Workstation, Shanghai, China
- *Correspondence: Lin Luo
| | - Xiaojin Zeng
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Yan Wu
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Fei An
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Jiahong Huang
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Hao Yang
- Zhongxu School Affiliated to East China Normal University, Chongqing, China
| | - Quanning Jiang
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Qiang Ou
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Jianjun Du
- College of Physical Education, Guizhou Normal University, Guiyang, China
| | - Naiqing Song
- Basic Education Research Center, Southwest University, Chongqing, China
- East China Normal University-Xuhui Postdoctoral Workstation, Shanghai, China
- Naiqing Song
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17
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Jimenez JL, Peng Z, Pagonis D. Systematic way to understand and classify the shared-room airborne transmission risk of indoor spaces. INDOOR AIR 2022; 32:e13025. [PMID: 35622715 DOI: 10.1111/ina.13025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 05/22/2023]
Affiliation(s)
- Jose L Jimenez
- Department of Chemistry and CIRES, University of Colorado, Boulder, Colorado, USA
| | - Zhe Peng
- Department of Chemistry and CIRES, University of Colorado, Boulder, Colorado, USA
| | - Demetrios Pagonis
- Department of Chemistry and CIRES, University of Colorado, Boulder, Colorado, USA
- Department of Chemistry and Biochemistry, Weber State University, Ogden, Utah, USA
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18
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Ding S, Lee JS, Mohamed MA, Ng BF. Infection risk of SARS-CoV-2 in a dining setting: Deposited droplets and aerosols. BUILDING AND ENVIRONMENT 2022; 213:108888. [PMID: 35169378 PMCID: PMC8828387 DOI: 10.1016/j.buildenv.2022.108888] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 05/06/2023]
Abstract
Considering that safe-distancing and mask-wearing measures are not strictly enforced in dining settings in the context of SARS-CoV-2, the infection risks of patrons in a dining outlet (e.g., a cafe) is assessed in this study. The size-resolved aerosol emission rate (AER) and droplets deposition rate (DDR) on dining plates from speaking were obtained through chamber measurements and droplet deposition visualization via fluorescent imaging technique (FIT), respectively. The AER from speaking was 24698 #/min in the size range of 0.3-5.5 μm, while the DDR was 365 #/min in the size range of 43-2847 μm. Furthermore, an infection risk model was adopted and revised to evaluate the infection risk of 120 diners for a "3-h event" in the cafe. In a four-person dining setting around a rectangular table, a diner seated diagonally across an infected person posed the least infection risk due to the deposited droplets on dining plates. The deposited droplets on a dining plate were dominant in possible viral transmission as compared to the long-range airborne route when a diner shared a table with the infected person. Yet, long-range airborne transmission had the potential to infect other diners in the cafe, even resulting in super-spreading events. A fresh air supply of 12.1-17.0 L/s per person is recommended for the cafe to serve 4-20 diners concurrently to minimize infection risks due to aerosols. Current ventilation standards (e.g., 8-10 L/s per person) for a cafe are not enough to avoid the airborne transmission of SARS-CoV-2.
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Affiliation(s)
- Shirun Ding
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Jia Shing Lee
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Mohamed Arif Mohamed
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Bing Feng Ng
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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19
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Wilson AM, Sleeth DK, Schaefer C, Jones RM. Transmission of Respiratory Viral Diseases to Health Care Workers: COVID-19 as an Example. Annu Rev Public Health 2022; 43:311-330. [DOI: 10.1146/annurev-publhealth-052120-110009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Health care workers (HCWs) can acquire infectious diseases, including coronavirus disease 2019 (COVID-19), from patients. Herein, COVID-19 is used with the source–pathway–receptor framework as an example to assess evidence for the role of aerosol transmission and indirect contact transmission of viral respiratory infectious diseases. Evidence for both routes is strong for COVID-19 and other respiratory viruses, but aerosol transmission is likely dominant for COVID-19. Key knowledge gaps about transmission processes and control strategies include the distribution of viable virus among respiratory aerosols of different sizes, the mechanisms and efficiency by which virus deposited on the facial mucous membrane moves to infection sites inside the body, and the performance of source controls such as face coverings and aerosol containment devices. To ensure that HCWs are adequately protected from infection, guidelines and regulations must be updated to reflect the evidence that respiratory viruses are transmitted via aerosols. Expected final online publication date for the Annual Review of Public Health, Volume 43 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Amanda M. Wilson
- Department of Family and Preventive Medicine, School of Medicine, University of Utah, Salt Lake City, Utah, USA;, ,
- Department of Community, Environment and Policy, Mel and Enid Zuckerman College of Public Health, The University of Arizona, Tucson, Arizona, USA
| | - Darrah K. Sleeth
- Department of Family and Preventive Medicine, School of Medicine, University of Utah, Salt Lake City, Utah, USA;, ,
| | - Camie Schaefer
- Department of Family and Preventive Medicine, School of Medicine, University of Utah, Salt Lake City, Utah, USA;, ,
| | - Rachael M. Jones
- Department of Family and Preventive Medicine, School of Medicine, University of Utah, Salt Lake City, Utah, USA;, ,
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20
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Abstract
Coronaviruses are well known airborne viruses that infect humans, other mammals, and birds. COVID-19 is the disease caused by the last emerging type of corona viruses; SARS-CoV-2 which resulted in the ongoing pandemic. Since its first identification, SARS-CoV-2 has spread globally causing significant morbidity and mortality. Fast and reliable diagnostic methods are crucial to control the virus outbreak. In this chapter, we summarize the traditional methods used to detect corona viruses. Various biosensors used for the detection of the virus antibodies and antigens were briefly discussed. Different biosensing approaches for the detection of corona viruses were presented with special emphasis on the reported biosensors for the detection of SARS-CoV-2. Major advancements in the biosensors area for corona viruses such as the use of cotton, magnetic nanoparticles, graphene, gold nanoparticles, and portable devices are highlighted. The challenges and future perspectives in the biosensors for the detection of corona viruses are discussed.
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21
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Nazaroff WW. Indoor aerosol science aspects of SARS-CoV-2 transmission. INDOOR AIR 2022; 32:e12970. [PMID: 34873752 DOI: 10.1111/ina.12970] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 11/17/2021] [Accepted: 11/26/2021] [Indexed: 05/04/2023]
Abstract
Knowledge about person-to-person transmission of SARS-CoV-2 is reviewed, emphasizing three components: emission of virus-containing particles and drops from infectious persons; transport and fate of such emissions indoors; and inhalation of viral particles by susceptible persons. Emissions are usefully clustered into three groups: small particles (diameter 0.1-5 µm), large particles (5-100 µm), and ballistic drops (>100 µm). Speaking generates particles and drops across the size spectrum. Small particles are removed from indoor air at room scale by ventilation, filtration, and deposition; large particles mainly deposit onto indoor surfaces. Proximate exposure enhancements are associated with large particles with contributions from ballistic drops. Masking and social distancing are effective in mitigating transmission from proximate exposures. At room scale, masking, ventilation, and filtration can contribute to limit exposures. Important information gaps prevent a quantitative reconciliation of the high overall global spread of COVID-19 with known transmission pathways. Available information supports several findings with moderate-to-high confidence: transmission occurs predominantly indoors; inhalation of airborne particles (up to 50 µm in diameter) contributes substantially to viral spread; transmission occurs in near proximity and at room scale; speaking is a major source of airborne SARS-CoV-2 virus; and emissions can occur without strong illness symptoms.
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Affiliation(s)
- William W Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, California, USA
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22
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Marr LC, Tang JW. A Paradigm Shift to Align Transmission Routes With Mechanisms. Clin Infect Dis 2021; 73:1747-1749. [PMID: 34415335 DOI: 10.1093/cid/ciab722] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Indexed: 11/14/2022] Open
Abstract
Current infection-control guidelines subscribe to a contact/droplet/airborne paradigm that is based on outdated understanding. Here, we propose to modify and align existing guidelines with a more accurate description of the different transmission routes. This will improve the effectiveness of control measures as more transmissible variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerge.
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Affiliation(s)
- Linsey C Marr
- Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia, USA
| | - Julian W Tang
- Respiratory Sciences, University of Leicester, Leicester, United Kingdom
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23
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Cortellessa G, Stabile L, Arpino F, Faleiros DE, van den Bos W, Morawska L, Buonanno G. Close proximity risk assessment for SARS-CoV-2 infection. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148749. [PMID: 34225157 PMCID: PMC8242194 DOI: 10.1016/j.scitotenv.2021.148749] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 05/04/2023]
Abstract
Although the interpersonal distance represents an important parameter affecting the risk of infection due to respiratory viruses, the mechanism of exposure to exhaled droplets remains insufficiently characterized. In this study, an integrated risk assessment is presented for SARS-CoV-2 close proximity exposure between a speaking infectious subject and a susceptible subject. It is based on a three-dimensional transient numerical model for the description of exhaled droplet spread once emitted by a speaking person, coupled with a recently proposed SARS-CoV-2 emission approach. Particle image velocimetry measurements were conducted to validate the numerical model. The contribution of the large droplets to the risk is barely noticeable only for distances well below 0.6 m, whereas it drops to zero for greater distances where it depends only on airborne droplets. In particular, for short exposures (10 s) a minimum safety distance of 0.75 m should be maintained to lower the risk below 0.1%; for exposures of 1 and 15 min this distance increases to about 1.1 and 1.5 m, respectively. Based on the interpersonal distances across countries reported as a function of interacting individuals, cultural differences, and environmental and sociopsychological factors, the approach presented here revealed that, in addition to intimate and personal distances, particular attention must be paid to exposures longer than 1 min within social distances (of about 1 m).
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Affiliation(s)
- G Cortellessa
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy
| | - L Stabile
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy
| | - F Arpino
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy
| | - D E Faleiros
- Maritime and Transport Technology, TU Delft, Netherlands
| | - W van den Bos
- Maritime and Transport Technology, TU Delft, Netherlands
| | - L Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia
| | - G Buonanno
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, FR, Italy; International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Qld, Australia.
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24
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Ding S, Teo ZW, Wan MP, Ng BF. Aerosols from speaking can linger in the air for up to nine hours. BUILDING AND ENVIRONMENT 2021; 205:108239. [PMID: 34393326 PMCID: PMC8349476 DOI: 10.1016/j.buildenv.2021.108239] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/01/2021] [Accepted: 08/07/2021] [Indexed: 05/06/2023]
Abstract
Airborne transmission of respiratory diseases has been under intense spotlight in the context of coronavirus disease 2019 (COVID-19) where continued resurgence is linked to the relaxation of social interaction measures. To understand the role of speech aerosols in the spread of COVID-19 globally, the lifetime and size distribution of the aerosols are studied through a combination of light scattering observation and aerosol sampling. It was found that aerosols from speaking suspended in stagnant air for up to 9 h with a half-life of 87.2 min. The half-life of the aerosols declined with the increase in air change per hour from 28 to 40 min (1 h-1), 10-14 min (4 h-1), to 4-6 min (9 h-1). The speech aerosols in the size range of about 0.3-2 μm (after dehydration) witnessed the longest lifetime compared to larger aerosols (2-10 μm). These results suggest that speech aerosols have the potential to transmit respiratory viruses across long duration (hours), and long-distance (over social distance) through the airborne route. These findings are important for researchers and engineers to simulate the airborne dispersion of viruses in indoor environments and to design new ventilation systems in the future.
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Affiliation(s)
- Shirun Ding
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Zhen Wei Teo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Man Pun Wan
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Bing Feng Ng
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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25
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Polianski IJ. Airborne infection with Covid-19? A historical look at a current controversy. Microbes Infect 2021; 23:104851. [PMID: 34126250 PMCID: PMC8193962 DOI: 10.1016/j.micinf.2021.104851] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 12/03/2022]
Abstract
Since the start of the COVID-19 pandemic, experts and the broader public have vigorously debated the means by which SARS CoV-2 is spread. And understandably so, for identifying the routes of transmission is crucial for selecting appropriate nonpharmaceutical interventions to control the pandemic. The most controversial question in the debate is the role played by airborne transmission. What is at stake is not just the clinical evidence, but the implications for public health policy, society, and psychology. Interestingly, however, the issue of airborne transmission is not a new controversy. It has reappeared throughout the history of western medicine. This essay traces the notion of airborne infection from its development in ancient medical theories to its manifestation in the modern era and its impact today.
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26
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Li Y, Nazaroff WW, Bahnfleth W, Wargocki P, Zhang Y. The COVID-19 pandemic is a global indoor air crisis that should lead to change: A message commemorating 30 years of Indoor Air. INDOOR AIR 2021; 31:1683-1686. [PMID: 34661309 PMCID: PMC8653253 DOI: 10.1111/ina.12928] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 05/19/2023]
Affiliation(s)
- Yuguo Li
- Department of Mechanical EngineeringThe University of Hong KongHong Kong SARChina
| | | | - William Bahnfleth
- Department of Architectural EngineeringPennsylvania State University (Penn State)University ParkPAUSA
| | - Pawel Wargocki
- Department of Civil EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Yinping Zhang
- Department of Building ScienceTsinghua UniversityBeijingChina
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27
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Li Y. Hypothesis: SARS-CoV-2 transmission is predominated by the short-range airborne route and exacerbated by poor ventilation. INDOOR AIR 2021; 31:921-925. [PMID: 34002888 PMCID: PMC8242709 DOI: 10.1111/ina.12837] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/13/2021] [Accepted: 03/24/2021] [Indexed: 05/07/2023]
Affiliation(s)
- Yuguo Li
- Department of Mechanical EngineeringThe University of Hong KongHong KongChina
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28
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Vouriot CVM, Burridge HC, Noakes CJ, Linden PF. Seasonal variation in airborne infection risk in schools due to changes in ventilation inferred from monitored carbon dioxide. INDOOR AIR 2021; 31:1154-1163. [PMID: 33682974 DOI: 10.1177/1420326x211043564] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 05/27/2023]
Abstract
The year 2020 has seen the world gripped by the effects of the COVID-19 pandemic. It is not the first time, nor will it be last, that our increasingly globalized world has been significantly affected by the emergence of a new disease. In much of the Northern Hemisphere, the academic year begins in September, and for many countries, September 2020 marked the return to full schooling after some period of enforced closure due to COVID-19. In this paper, we focus on the airborne spread of disease and investigate the likelihood of transmission in school environments. It is crucial to understand the risk airborne infection from COVID-19 might pose to pupils, teachers, and their wider social groups. We use monitored CO2 data from 45 classrooms in 11 different schools from within the UK to estimate the likelihood of infection occurring within classrooms regularly attended by the same staff and pupils. We determine estimates of the number of secondary infections arising via the airborne route over pre/asymptomatic periods on a rolling basis. Results show that, assuming relatively quiet desk-based work, the number of secondary infections is likely to remain reassuringly below unity; however, it can vary widely between classrooms of the same school even when the same ventilation system is present. Crucially, the data highlight significant variation with the seasons with January being nearly twice as risky as July. We show that such seasonal variations in risk due to changes in ventilation rates are robust and our results hold for wide variations in disease parameterizations, suggesting our results may be applied to a number of different airborne diseases.
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Affiliation(s)
- Carolanne V M Vouriot
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Henry C Burridge
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Catherine J Noakes
- School of Civil Engineering, Woodhouse Lane, University of Leeds, Leeds, UK
| | - Paul F Linden
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, UK
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29
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Aerosols should not be defined by distance travelled. J Hosp Infect 2021; 115:131-132. [PMID: 34048848 PMCID: PMC8149158 DOI: 10.1016/j.jhin.2021.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 05/16/2021] [Indexed: 01/21/2023]
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30
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Li Y. The respiratory infection inhalation route continuum. INDOOR AIR 2021; 31:279-281. [PMID: 33620780 PMCID: PMC8014729 DOI: 10.1111/ina.12806] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 05/05/2023]
Affiliation(s)
- Yuguo Li
- Department of Mechanical EngineeringThe University of Hong KongHong KongChina
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