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Alhussain H, Ghani S, Eltai NO. Breathing Clean Air: Navigating Indoor Air Purification Techniques and Finding the Ideal Solution. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2024; 21:1107. [PMID: 39200716 PMCID: PMC11354768 DOI: 10.3390/ijerph21081107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 08/05/2024] [Accepted: 08/07/2024] [Indexed: 09/02/2024]
Abstract
The prevalence of airborne pathogens in indoor environments presents significant health risks due to prolonged human occupancy. This review addresses diverse air purification systems to combat airborne pathogens and the factors influencing their efficacy. Indoor aerosols, including bioaerosols, harbor biological contaminants from respiratory emissions, highlighting the need for efficient air disinfection strategies. The COVID-19 pandemic has emphasized the dangers of airborne transmission, highlighting the importance of comprehending how pathogens spread indoors. Various pathogens, from viruses like SARS-CoV-2 to bacteria like Mycobacterium (My) tuberculosis, exploit unique respiratory microenvironments for transmission, necessitating targeted air purification solutions. Air disinfection methods encompass strategies to reduce aerosol concentration and inactivate viable bioaerosols. Techniques like ultraviolet germicidal irradiation (UVGI), photocatalytic oxidation (PCO), filters, and unipolar ion emission are explored for their specific roles in mitigating airborne pathogens. This review examines air purification systems, detailing their operational principles, advantages, and limitations. Moreover, it elucidates key factors influencing system performance. In conclusion, this review aims to provide practical knowledge to professionals involved in indoor air quality management, enabling informed decisions for deploying efficient air purification strategies to safeguard public health in indoor environments.
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Affiliation(s)
- Hashim Alhussain
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar;
| | - Saud Ghani
- Department of Industrial and Mechanical Engineering, Qatar University, Doha P.O. Box 2713, Qatar;
| | - Nahla O. Eltai
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar;
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Văruț RM, Rotaru LT, Cimpoesu D, Corlade M, Singer CE, Popescu AIS, Popescu C, Iulian-Nicolae I, Mocanu A, Popescu M, Butoi MA, Nicolaescu OE. Enhanced Antibacterial Efficacy of Bioceramic Implants Functionalized with Ciprofloxacin: An In Silico and In Vitro Study. Pharmaceutics 2024; 16:998. [PMID: 39204343 PMCID: PMC11358898 DOI: 10.3390/pharmaceutics16080998] [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: 06/14/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 09/04/2024] Open
Abstract
This study explores the antibacterial efficacy and cytotoxicity of ciprofloxacin-functionalized bioceramic implants. We synthesized hydroxyapatite-ciprofloxacin (HACPXCS) composites and applied them to titanium substrates (Ti-HA-CPX), evaluating their performance in vitro against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). Antibacterial activity was assessed using the Kirby-Bauer disc diffusion method, while cytotoxicity was tested using mesenchymal stem cells. The results demonstrated that Ti-HA-CPX exhibited superior antibacterial activity, with inhibition zones of 33.5 mm (MIC 0.5 µg/mL) for Staphylococcus aureus (ATCC 25923) and 27.5 mm (MIC 0.25 µg/mL) for Escherichia coli (ATCC 25922). However, Ti-HA-CPX showed moderate cytotoxicity (80% cell viability). HACPXCS composites, whether chemically synthesized or mechanically mixed (HACPXMM), also displayed significant antibacterial activity, but with cytotoxicity ranging from low to moderate levels. Molecular docking studies confirmed strong binding affinities between ciprofloxacin and bacterial proteins, correlating with enhanced antibacterial efficacy. These findings suggest that Ti-HA-CPX composites offer a promising approach for single-stage surgical interventions in treating chronic osteomyelitis and infected fractures, balancing antibacterial effectiveness with manageable cytotoxicity.
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Affiliation(s)
- Renata-Maria Văruț
- Research Methodology Department, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania;
| | - Luciana Teodora Rotaru
- Emergency Medicine and First Aid Department, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (L.T.R.); (M.A.B.)
| | - Diana Cimpoesu
- Emergency St. Spiridon Hospital, Faculty of Medicine, University of Medicine and Pharmacy Gr. T. Popa, 700115 Iasi, Romania; (D.C.); (M.C.)
| | - Mihaela Corlade
- Emergency St. Spiridon Hospital, Faculty of Medicine, University of Medicine and Pharmacy Gr. T. Popa, 700115 Iasi, Romania; (D.C.); (M.C.)
| | - Cristina Elena Singer
- Department of Mother and Baby, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (C.E.S.); (I.I.-N.)
| | - Alin Iulian Silviu Popescu
- Department of Internal Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania
| | - Cristina Popescu
- Department of Anatomy, University of Medicine and Pharmacy, Discipline of Anatomy, 200349 Craiova, Romania
| | - Iliescu Iulian-Nicolae
- Department of Mother and Baby, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (C.E.S.); (I.I.-N.)
| | - Adriana Mocanu
- Pharmacist at the Military Emergency Clinical Hospital, 200749 Craiova, Romania;
| | - Mihaela Popescu
- Department of Endocrinology, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania;
| | - Mihai Alexandru Butoi
- Emergency Medicine and First Aid Department, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; (L.T.R.); (M.A.B.)
| | - Oana Elena Nicolaescu
- Department of Pharmaceutical Technique, University of Medicine and Pharmacy, Discipline of Anatomy, 200349 Craiova, Romania;
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Ballesteros Álvarez J, Romero Barriuso A, Villena Escribano B, Rodríguez Sáiz A, González-Gaya C. Investigating the effectiveness of a new indoor ventilation model in reducing the spread of disease: A case of sports centres amid the COVID-19 pandemic. Heliyon 2024; 10:e27877. [PMID: 38560668 PMCID: PMC10979208 DOI: 10.1016/j.heliyon.2024.e27877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 03/01/2024] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
The ventilation of buildings is crucial to ensure indoor health, especially when demanding physical activities are carried out indoors, and the pandemic has highlighted the need to develop new management methods to ensure adequate ventilation. In Spain, there are no specific ventilation regulations to prevent the spread of pathogens such as the coronavirus. Therefore, it is necessary to have a theoretical tool for calculating occupancy to maintain sports facilities in optimal safety conditions. The proposed theoretical method is based on the analysis of mathematical expressions from European standardisation documents and uses the concentration of CO2 as a bioeffluent. It is also based on the concept of background and critical concentration, which allows its application to be extrapolated to future crises caused by pathogens. This study presents a unique and novel dataset for sports centres. For this purpose, the calculation methods were applied to the data set provided by Mostoles City Council, Spain, during the pandemic years with the highest incidence of COVID-19, when the government introduced the assimilation of COVID-19 sick leave to occupational accidents. The data on this type of sick leave provided by the City Council correspond to the period between March 2020 and February 2022. Similarly, the data on the average use of sports facilities by activity, provided by the Sports Department, correspond to the years 2020 and 2021. In this way, it was possible to verify the effectiveness in preventing the spread of any type of coronavirus. In conclusion, the implementation of a theoretical occupancy calculation method based on the concentration of carbon dioxide as a bioeffluent can be an effective tool for the management of future crises caused by pathogens or hazardous chemicals in the air, and demonstrated its effectiveness in sports centres such as gyms, sports fields, and indoor swimming pools during the COVID-19 pandemic.
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Affiliation(s)
- J.M. Ballesteros Álvarez
- Department of Architectural Constructions & Construction and Land Engineering, University of Burgos, Burgos, Spain
| | | | - B.M. Villena Escribano
- Departmet of Construction and Manufacturing Engineering, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - A. Rodríguez Sáiz
- Department of Architectural Constructions & Construction and Land Engineering, University of Burgos, Burgos, Spain
| | - C. González-Gaya
- Departmet of Construction and Manufacturing Engineering, Universidad Nacional de Educación a Distancia, Madrid, Spain
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Satheesan MK, Tsang TW, Wong LT, Mui KW. The air we breathe: Numerical investigation of ventilation strategies to mitigate airborne dispersion of MERS-CoV in inpatient wards. Heliyon 2024; 10:e26159. [PMID: 38404798 PMCID: PMC10884507 DOI: 10.1016/j.heliyon.2024.e26159] [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: 06/15/2023] [Revised: 01/03/2024] [Accepted: 02/08/2024] [Indexed: 02/27/2024] Open
Abstract
Ventilation strategies for infection control in hospitals has been predominantly directed towards isolation rooms and operating theatres, with relatively less emphasis on perceived low risk spaces, such as general wards. Typically, the ventilation systems in general wards are intended to optimize patient thermal comfort and energy conservation. The emission of pathogens from exhalation activity, such as sneezing, by an undiagnosed infectious patient admitted to general wards, is a significant concern for infection outbreaks. However, the ventilation guidelines for general wards with respect to infection control are vague. This research article presents a numerical study on the effect of varying air change rates (3 h-1, 6 h-1, 9 h-1, 13 h-1) and exhaust flow rates (10%, 50% of supply air quantity) on the concentration of airborne pathogens in a mechanically ventilated general inpatient ward. The findings imply that the breathing zone directly above the source patient has the highest level of pathogen exposure, followed by the breathing zones at the bedside and adjacent patients close to the source patient. The dispersion of pathogens throughout the ward over time is also apparent. However, a key difference while adopting a lower ACH (3 h-1) and a higher ACH (13 h-1) in this study was that the latter had a significantly lower number of suspended pathogens in the breathing zone than the former. Thus, this research suggests high ventilation rates for general wards, contrary to current ventilation standards. In addition, combining a higher air change rate (13 h-1) with a high exhaust flow rate (50% of supply air) through a local exhaust grille dramatically reduced suspended pathogens within the breathing zone, further mitigating the risk of pathogen exposure for ward users. Therefore, this study presents an effective ventilation technique to dilute and eliminate airborne infectious pathogens, minimizing their concentration and the risk of infection.
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Affiliation(s)
- Manoj Kumar Satheesan
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Tsz Wun Tsang
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Ling Tim Wong
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Kwok Wai Mui
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
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Luceri A, Francese R, Perero S, Lembo D, Ferraris M, Balagna C. Antibacterial and Antiviral Activities of Silver Nanocluster/Silica Composite Coatings Deposited onto Air Filters. ACS APPLIED MATERIALS & INTERFACES 2024; 16:3955-3965. [PMID: 38195426 DOI: 10.1021/acsami.3c13843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
The indoor air quality should be better controlled and improved to avoid numerous health issues. Even if different devices are developed for air filtration, the proliferation of microorganisms under certain conditions must be controlled. For this purpose, a silver nanocluster/silica composite coating was deposited via a cosputtering technique onto fiber glass and polymeric based substrates. The aim of this work is focused on the evaluation of the antibacterial and antiviral effects of the developed coating. The preliminary results of the compositional and morphological tests showed an evenly distributed coating on filters surfaces. Several antibacterial tests were performed, confirming strong effect both in qualitative and quantitative methods, against S. epidermidis and E. coli. To understand if the coating can stop the proliferation of bacteria colonies spread on it, simulation of everyday usage of filters was performed, nebulizing bacteria solution with high colonies concentration and evaluating the inhibition of bacteria growth. Additionally, a deep understanding of the virucidal action and mechanism of Ag nanoclusters of the coating was performed. The effect of the coating both in aqueous medium and in dry methods was evaluated, in comparison with analysis on ions release. The virucidal performances are assessed against the human coronavirus OC43 strain (HCoV-OC43).
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Affiliation(s)
- Angelica Luceri
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Rachele Francese
- Department of Clinical and Biological Sciences, Laboratory of Molecular Virology and Antiviral Research, University of Turin, Regione Gonzole 10, 10043 Orbassano (TO), Italy
| | - Sergio Perero
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - David Lembo
- Department of Clinical and Biological Sciences, Laboratory of Molecular Virology and Antiviral Research, University of Turin, Regione Gonzole 10, 10043 Orbassano (TO), Italy
| | - Monica Ferraris
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Cristina Balagna
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
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Kompatscher K, van der Vossen JMBM, van Heumen SPM, Traversari AAL. Scoping review on the efficacy of filter and germicidal technologies for capture and inactivation of micro-organisms and viruses. J Hosp Infect 2023; 142:39-48. [PMID: 37797657 DOI: 10.1016/j.jhin.2023.08.026] [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: 07/14/2023] [Revised: 08/24/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023]
Abstract
The COVID-19 (SARS-CoV-2) pandemic increased the focus on preventing contamination with airborne pathogens (e.g. viruses, bacteria, and fungi) by reducing their concentration. Filtration, UV or ionization technologies could contribute to air purification of the indoor environment and inactivation of micro-organisms. The aim of this study was to identify the relevant literature and review the scientific evidence presented on the efficacy of filter and germicidal technologies (e.g. non-physical technologies) in air purification applications used to capture and inactivate micro-organisms and airborne viruses (e.g. SARS-CoV-2, rhinovirus, influenzavirus) in practice. A scoping review was performed to collect literature. Adopting exclusion criteria resulted in a final number of 75 studies to be included in this research. Discussion is presented on inactivation efficiencies of ultraviolet germicidal irradiation (UVGI) and ionization applications in laboratory studies and in practice. Specific attention is given to studies relating the use of UVGI and ionization to inactivation of the SARS-CoV-2 virus. Based on the consulted literature, no unambiguous conclusions can be drawn regarding the effectiveness of air purification technologies in practice. The documented and well-controlled laboratory studies do not adequately represent the practical situation in which the purifier systems are used.
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Affiliation(s)
- K Kompatscher
- Netherlands Organization for Applied Scientific Research, Department of Building and Energy Systems, Delft, The Netherlands.
| | - J M B M van der Vossen
- Netherlands Organization for Applied Scientific Research, Department of Microbiology and Systems Biology, Leiden, The Netherlands
| | - S P M van Heumen
- Netherlands Organization for Applied Scientific Research, Department of Building and Energy Systems, Delft, The Netherlands
| | - A A L Traversari
- Netherlands Organization for Applied Scientific Research, Department of Building and Energy Systems, Delft, The Netherlands
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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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Chawla H, Anand P, Garg K, Bhagat N, Varmani SG, Bansal T, McBain AJ, Marwah RG. A comprehensive review of microbial contamination in the indoor environment: sources, sampling, health risks, and mitigation strategies. Front Public Health 2023; 11:1285393. [PMID: 38074709 PMCID: PMC10701447 DOI: 10.3389/fpubh.2023.1285393] [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: 08/29/2023] [Accepted: 10/25/2023] [Indexed: 12/18/2023] Open
Abstract
The quality of the indoor environment significantly impacts human health and productivity, especially given the amount of time individuals spend indoors globally. While chemical pollutants have been a focus of indoor air quality research, microbial contaminants also have a significant bearing on indoor air quality. This review provides a comprehensive overview of microbial contamination in built environments, covering sources, sampling strategies, and analysis methods. Microbial contamination has various origins, including human occupants, pets, and the outdoor environment. Sampling strategies for indoor microbial contamination include air, surface, and dust sampling, and various analysis methods are used to assess microbial diversity and complexity in indoor environments. The review also discusses the health risks associated with microbial contaminants, including bacteria, fungi, and viruses, and their products in indoor air, highlighting the need for evidence-based studies that can relate to specific health conditions. The importance of indoor air quality is emphasized from the perspective of the COVID-19 pandemic. A section of the review highlights the knowledge gap related to microbiological burden in indoor environments in developing countries, using India as a representative example. Finally, potential mitigation strategies to improve microbiological indoor air quality are briefly reviewed.
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Affiliation(s)
- Hitikk Chawla
- Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
| | - Purnima Anand
- Department of Microbiology, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Kritika Garg
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, India
| | - Neeru Bhagat
- Department of Microbiology, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Shivani G. Varmani
- Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
| | - Tanu Bansal
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | - Andrew J. McBain
- School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Ruchi Gulati Marwah
- Department of Microbiology, Bhaskaracharya College of Applied Sciences, University of Delhi, New Delhi, India
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Tu J, Hu L, Mohammed KJ, Le BN, Chen P, Ali E, Ali HE, Sun L. Application of logistic regression, support vector machine and random forest on the effects of titanium dioxide nanoparticles using macroalgae in treatment of certain risk factors associated with kidney injuries. ENVIRONMENTAL RESEARCH 2023; 220:115167. [PMID: 36584853 DOI: 10.1016/j.envres.2022.115167] [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: 11/14/2022] [Revised: 12/16/2022] [Accepted: 12/25/2022] [Indexed: 06/17/2023]
Abstract
The use of titanium dioxide (TiO2) nanoparticles in many biological and technical domains is on the rise. There hasn't been much research on the toxicity of titanium dioxide nanoparticles in biological systems, despite their ubiquitous usage. In the current investigation, samples were exposed to various dosages of TiO2 nanoparticles for 4 days, 1 month, and 2 months following treatment. ICP-AES was used to dose TiO2 into the tissues, and the results showed that the kidney had a significant TiO2 buildup. On the other hand, apoptosis of renal tubular cells is one of the most frequent cellular processes contributing to kidney disease (KD). Nevertheless, the impact of macroalgal seaweed extract on KD remains undetermined. In this work, machine learning (ML) approaches have been applied to develop prediction algorithms for acute kidney injury (AKI) by use of titanium dioxide and macroalgae in hospitalized patients. Fifty patients with (AKI) and 50 patients (non-AKI group) have been admitted and considered. Regarding demographic data, and laboratory test data as input parameters, support vector machine (SVM), and random forest (RF) are utilized to build models of AKI prediction and compared to the predictive performance of logistic regression (LR). Due to its strong antioxidant and anti-inflammatory powers, the current research ruled out the potential of using G. oblongata red macro algae as a source for a variety of products for medicinal uses. Despite a high and fast processing of algorithms, logistic regression showed lower overfitting in comparison to SVM, and Random Forest. The dataset is subjected to algorithms, and the categorization of potential risk variables yields the best results. AKI samples showed significant organ defects than non-AKI ones. Multivariate LR indicated that lymphocyte, and myoglobin (MB) ≥ 1000 ng/ml were independent risk parameters for AKI samples. Also, GCS score (95% CI 1.4-8.3 P = 0.014) were the risk parameters for 60-day mortality in samples with AKI. Also, 90-day mortality in AKI patients was significantly high (P < 0.0001). In compared to the control group, there were no appreciable changes in the kidney/body weight ratio or body weight increases. Total thiol levels in kidney homogenate significantly decreased, and histopathological analysis confirmed these biochemical alterations. According to the results, oral TiO2 NP treatment may cause kidney damage in experimental samples.
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Affiliation(s)
- Jianxin Tu
- Department of Rheumatology and Immunology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Lingzhen Hu
- Department of Rheumatology and Immunology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Khidhair Jasim Mohammed
- Air Conditioning and Refrigeration Techniques Engineering Department, Al-Mustaqbal University College, Babylon 51001, Iraq
| | - Binh Nguyen Le
- Institute of Research and Development, Duy Tan University, Da Nang, VietNam; School of Engineering & Technology, Duy Tan University, Da Nang, VietNam.
| | - Peirong Chen
- Department of Rheumatology and Immunology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Elimam Ali
- Department of Civil Engineering, College of Engineering in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia
| | - H Elhosiny Ali
- Advanced Functional Materials & Optoelectronic Laboratory (AFMOL), Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; Research Center for Advanced Materials Science (RCAMS), King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; Physics Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt
| | - Li Sun
- Department of Rheumatology and Immunology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China.
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Argyropoulos CD, Skoulou V, Efthimiou G, Michopoulos AK. Airborne transmission of biological agents within the indoor built environment: a multidisciplinary review. AIR QUALITY, ATMOSPHERE, & HEALTH 2022; 16:477-533. [PMID: 36467894 PMCID: PMC9703444 DOI: 10.1007/s11869-022-01286-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
The nature and airborne dispersion of the underestimated biological agents, monitoring, analysis and transmission among the human occupants into building environment is a major challenge of today. Those agents play a crucial role in ensuring comfortable, healthy and risk-free conditions into indoor working and leaving spaces. It is known that ventilation systems influence strongly the transmission of indoor air pollutants, with scarce information although to have been reported for biological agents until 2019. The biological agents' source release and the trajectory of airborne transmission are both important in terms of optimising the design of the heating, ventilation and air conditioning systems of the future. In addition, modelling via computational fluid dynamics (CFD) will become a more valuable tool in foreseeing risks and tackle hazards when pollutants and biological agents released into closed spaces. Promising results on the prediction of their dispersion routes and concentration levels, as well as the selection of the appropriate ventilation strategy, provide crucial information on risk minimisation of the airborne transmission among humans. Under this context, the present multidisciplinary review considers four interrelated aspects of the dispersion of biological agents in closed spaces, (a) the nature and airborne transmission route of the examined agents, (b) the biological origin and health effects of the major microbial pathogens on the human respiratory system, (c) the role of heating, ventilation and air-conditioning systems in the airborne transmission and (d) the associated computer modelling approaches. This adopted methodology allows the discussion of the existing findings, on-going research, identification of the main research gaps and future directions from a multidisciplinary point of view which will be helpful for substantial innovations in the field.
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Affiliation(s)
| | - Vasiliki Skoulou
- B3 Challenge Group, Chemical Engineering, School of Engineering, University of Hull, Cottingham Road, Hull, HU6 7RX UK
| | - Georgios Efthimiou
- Centre for Biomedicine, Hull York Medical School, University of Hull, Cottingham Road, Hull, HU6 7RX UK
| | - Apostolos K. Michopoulos
- Energy & Environmental Design of Buildings Research Laboratory, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
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11
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Gu Y, Zhong K, Cao R, Yang Z. Aqueous lithium chloride solution as a non-toxic bactericidal and fungicidal disinfectant for air-conditioning systems: Efficacy and mechanism. ENVIRONMENTAL RESEARCH 2022; 212:113112. [PMID: 35346655 DOI: 10.1016/j.envres.2022.113112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
Airborne pathogenic bacteria and fungi transmitted through air-conditioning (AC) systems have been identified as a major public health risk. Air scrubbing is a promising liquid-based air disinfection technique that captures and inactivates airborne pathogens in liquid disinfectants. However, owing to the drawbacks of irritating odor and toxicity, the commonly-used chemical disinfectants cannot be employed for AC systems. This study aimed to unveil the inactivation performance and mechanism of non-toxic and chemically stable aqueous lithium chloride (LiCl) solution-the popular liquid desiccant in the AC systems-as a user-friendly disinfectant. Four prominent airborne pathogenic bacteria and fungi were exposed to the LiCl solution under various conditions. The inactivation effects were quantified with fluorescence-staining-based confocal microscopy and verified with the pathogens' membrane integrity variations, intracellular substance leakage, and morphological changes. Results showed that LiCl solution was remarkably efficient in inactivating the pathogens within 60 min, with an efficacy of 35.2-96.2%. The solution's inactivation ability was promoted by increasing the temperatures and concentrations; however, it appeared insensitive to exposure time over 30 min. We then explored the inactivation mechanism of LiCl solution by assessing cellular protein leakages and compared the inactivation rates with those of NaCl solution. The extracellular protein increased by over 470% after being exposed to LiCl solution. The inactivation rate was also considerably higher than in NaCl solution under the same osmotic pressure (24.79 MPa). We suggest that apart from osmotic pressure, the inactivation is reinforced by Li+-specific properties, including its strong water attraction that deprived the solvation shells of microbial protein and caused protein denaturation. We propose that aqueous LiCl solution may act as a user-friendly disinfectant for air-scrubbing due to its attractive characteristics, including its non-toxicity, odorless nature, and chemical stability. These findings may open up a "green" way to disinfect airborne pathogens and safeguard public health.
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Affiliation(s)
- Yuqian Gu
- Department of Civil Engineering, School of Environmental Science & Engineering, Donghua University, 201620, 2999, North Renmin Road, Songjiang District, Shanghai, China
| | - Ke Zhong
- Department of Civil Engineering, School of Environmental Science & Engineering, Donghua University, 201620, 2999, North Renmin Road, Songjiang District, Shanghai, China
| | - Rong Cao
- Department of Radiology, Shanghai General Hospital, Shanghai Jiao Tong University, China
| | - Zili Yang
- Department of Civil Engineering, School of Environmental Science & Engineering, Donghua University, 201620, 2999, North Renmin Road, Songjiang District, Shanghai, China.
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12
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Dudek D, Janus M. Photoactive Cements: A Review. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5407. [PMID: 35955340 PMCID: PMC9369819 DOI: 10.3390/ma15155407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
This article presents a short overview of modified cements with photocatalytic activity. First, the types and three main methods of obtaining photoactive cements are presented. The most frequently used modification method is the incorporation of a photocatalyst into the total mass of the cement. The second group analyzed is cements obtained by applying a thin layer of photoactive materials, e.g., paints, enamels, or TiO2 suspensions, using various techniques. The third group is cement mortars with a thick layer of photoactive concrete on the top. In addition, methods for determining the photoactivity of cement composites, mechanical properties, and physicochemical parameters of such materials are briefly presented. Finally, examples of investments with the use of photoactive cements and development prospects are shown.
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13
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Prophylactic Architecture: Formulating the Concept of Pandemic-Resilient Homes. BUILDINGS 2022. [DOI: 10.3390/buildings12070927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The lockdown instituted during the COVID-19 pandemic has drawn the world’s attention to the importance of homes as integrated structures for practicing all aspects of life. The home has been transformed from a mere place to live into a complete piece of infrastructure accommodating all activities of life, including study, work, shopping, exercise, entertainment, and even telehealth. Although quarantines were necessary to protect against viral infection, we have faced social and psychological challenges due to the failure of the current home design to accommodate the new lockdown lifestyle during the pandemic. Thus, this study aims to set a foundation for the development and design of resilient homes in a post-quarantine world by establishing a comprehensive framework for quarantine-resilient homes. The framework was established on the basis of the relevant literature and proposals from architects and experts. It brings a perspective to the future requirements of homes so as to provide architects, stakeholders, and policymakers with the appropriate knowledge to mitigate the impact of lockdowns on mental health and well-being in residential buildings by focusing on the physical and architectural environment.
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14
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Mahfooz S, Itrat M, Uddin H, Khan TN. Unani medicinal herbs as potential air disinfectants: an evidence-based review. REVIEWS ON ENVIRONMENTAL HEALTH 2022; 37:155-168. [PMID: 34384009 DOI: 10.1515/reveh-2021-0087] [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: 06/26/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVES Indoor air quality has a significant impact on our health and quality of life, as people spends 80-90% of their time indoors. Fumigation of several medicinal herbs has been recommended by Unani scholars to improve air quality, but their efficacy in air purification is still unknown. Hence, this article aims to discuss the applicability of proposed medicinal herbs in the light of current researches. METHODS A manual literature survey of classical Unani texts was conducted to collect information about the herbs recommended for air purification. In addition, research databases such as PubMed, Google Scholar, and ScienceDirect were extensively searched for evidence on the efficacy and mechanism of action of the suggested herbs in air purification. RESULTS In classical Unani texts, authors have found descriptions of 26 herbs that have been recommended for improving air quality. In-vitro studies have confirmed the antimicrobial activity of 19 of these herbs. Moreover, the efficacy of Styrax benzoin, Commiphora myrrha and Acorus calamus fumigation on aerial microbes have also been validated by studies. CONCLUSIONS The findings of the literature review clearly demonstrated that the herbs recommended by Unani scholars for air purification have broad-spectrum antimicrobial activity, indicating that these herbs could be a potential candidate for air disinfectant. Therefore, authors recommend the further researches on proposed herbs to validate their efficiency against airborne pathogens in the vapour phase.
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Affiliation(s)
- Shaista Mahfooz
- Department of Tahaffuzi wa Samaji Tib (Preventive and Social Medicine), National Institute of Unani Medicine, Bangalore, Karnataka, India
| | - Malik Itrat
- Department of Tahaffuzi wa Samaji Tib (Preventive and Social Medicine), National Institute of Unani Medicine, Bangalore, Karnataka, India
| | - Hamid Uddin
- Department of Ilmul Saidla (Unani Pharmacy), National Institute of Unani Medicine, Bangalore, Karnataka, India
| | - Tariq Nadeem Khan
- Department of Kulliyat-e-Tib (Basic Principles of Unani Medicine), National Institute of Unani Medicine, Bengaluru, Karnataka, India
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15
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Izadyar N, Miller W. Ventilation strategies and design impacts on indoor airborne transmission: A review. BUILDING AND ENVIRONMENT 2022; 218:109158. [PMID: 35573806 PMCID: PMC9075988 DOI: 10.1016/j.buildenv.2022.109158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/26/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
The COVID-19 outbreak has brought the indoor airborne transmission issue to the forefront. Although ventilation systems provide clean air and dilute indoor contaminated air, there is strong evidence that airborne transmission is the main route for contamination spread. This review paper aims to critically investigate ventilation impacts on particle spread and identify efficient ventilation strategies in controlling aerosol distribution in clinical and non-clinical environments. This article also examines influential ventilation design features (i.e., exhaust location) affecting ventilation performance in preventing aerosols spread. This paper shortlisted published documents for a review based on identification (keywords), pre-processing, screening, and eligibility of these articles. The literature review emphasizes the importance of ventilation systems' design and demonstrates all strategies (i.e., mechanical ventilation) could efficiently remove particles if appropriately designed. The study highlights the need for occupant-based ventilation systems, such as personalized ventilation instead of central systems, to reduce cross-infections. The literature underlines critical impacts of design features like ventilation rates and the number and location of exhausts and suggests designing systems considering airborne transmission. This review underpins that a higher ventilation rate should not be regarded as a sole indicator for designing ventilation systems because it cannot guarantee reducing risks. Using filtration and decontamination devices based on building functionalities and particle sizes can also increase ventilation performance. This paper suggests future research on optimizing ventilation systems, particularly in high infection risk spaces such as multi-storey hotel quarantine facilities. This review contributes to adjusting ventilation facilities to control indoor aerosol transmission.
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Affiliation(s)
- Nima Izadyar
- School of Built Environment, College of Engineering and Science, Victoria University, Melbourne, VIC, Australia
| | - Wendy Miller
- School of Architecture & Built Environment, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD, 4001, Australia
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16
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Kumar A, Soni V, Singh P, Parwaz Khan AA, Nazim M, Mohapatra S, Saini V, Raizada P, Hussain CM, Shaban M, Marwani HM, Asiri AM. Green aspects of photocatalysts during corona pandemic: a promising role for the deactivation of COVID-19 virus. RSC Adv 2022; 12:13609-13627. [PMID: 35530385 PMCID: PMC9073611 DOI: 10.1039/d1ra08981a] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 03/17/2022] [Indexed: 12/14/2022] Open
Abstract
The selection of a facile, eco-friendly, and effective methodology is the need of the hour for efficient curing of the COVID-19 virus in air, water, and many food products. Recently, semiconductor-based photocatalytic methodologies have provided promising, green, and sustainable approaches to battle against viral activation via the oxidative capabilities of various photocatalysts with excellent performance under moderate conditions and negligible by-products generation as well. Considering this, recent advances in photocatalysis for combating the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are inclusively highlighted. Starting from the origin to the introduction of the coronavirus, the significant potential of photocatalysis against viral prevention and -disinfection is discussed thoroughly. Various photocatalytic material-based systems including metal-oxides, metal-free and advanced 2D materials (MXenes, MOFs and COFs) are systematically examined to understand the mechanistic insights of virus-disinfection in the human body to fight against COVID-19 disease. Also, a roadmap toward sustainable solutions for ongoing COVID-19 contagion is also presented. Finally, the challenges in this field and future perspectives are comprehensively discussed involving the bottlenecks of current photocatalytic systems along with potential recommendations to deal with upcoming pandemic situations in the future.
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Affiliation(s)
- Abhinandan Kumar
- School of Advanced Chemical Sciences, Shoolini University Solan Himachal Pradesh 173229 India
| | - Vatika Soni
- School of Advanced Chemical Sciences, Shoolini University Solan Himachal Pradesh 173229 India
| | - Pardeep Singh
- School of Advanced Chemical Sciences, Shoolini University Solan Himachal Pradesh 173229 India
| | - Aftab Aslam Parwaz Khan
- Center of Excellence for Advanced Materials Research, King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia
- Chemistry Department, Faculty of Science, King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia
| | - Mohammed Nazim
- Department of Chemical Engineering, Kumoh National Institute of Technology 61 Daehak-ro Gumi-si Gyeongbuk-do 39177 Republic of Korea
| | - Satyabrata Mohapatra
- University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University Dwarka New Delhi 110078 India
| | - Vipin Saini
- Maharishi Markandeshwar Medical College Kumarhatti Solan Himachal Pradesh 173229 India
| | - Pankaj Raizada
- School of Advanced Chemical Sciences, Shoolini University Solan Himachal Pradesh 173229 India
| | | | - Mohamed Shaban
- Department of Physics, Faculty of Science, Beni-Suef University Beni-Suef 62514 Egypt
| | - Hadi M Marwani
- Center of Excellence for Advanced Materials Research, King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia
- Chemistry Department, Faculty of Science, King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia
| | - Abdullah M Asiri
- Center of Excellence for Advanced Materials Research, King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia
- Chemistry Department, Faculty of Science, King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia
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17
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Xu Q, Goh HC, Mousavi E, Nabizadeh Rafsanjani H, Varghese Z, Pandit Y, Ghahramani A. Towards Personalization of Indoor Air Quality: Review of Sensing Requirements and Field Deployments. SENSORS (BASEL, SWITZERLAND) 2022; 22:3444. [PMID: 35591133 PMCID: PMC9104953 DOI: 10.3390/s22093444] [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: 03/31/2022] [Revised: 04/20/2022] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
As humans spend more time indoors, ensuring acceptable indoor air quality (IAQ) through ubiquitous sensing systems has become a necessity. Although extensive studies have been conducted on the IAQ sensing systems, a holistic review of the performance and deployment of Ubiquitous IAQ Sensing (UIAQS) systems with associated requirements in IAQ sensing standards is still lacking. In this study, we first reviewed IAQ pollutants and other IAQ-related factors and the associated requirements in the prominent IAQ sensing standards. We found that while non-pollutant factors are influential on occupants' perception of IAQ and their satisfaction, they do not have evaluation metrics in the IAQ standards. Then, we systematically reviewed field studies on UIAQS technologies in the literature. Specific classes of information were recorded and analyzed further. We found that the majority of the UIAQS systems did not meet the requirements of the prominent IAQ sensing standards and identified four primary research gaps. We concluded that a new holistic and personalized approach that incorporates UIAQS measurements and subjective feedback is needed. This study provides valuable insights for researchers and policymakers to better improve UIAQS technologies by developing personalized IAQ sensors and sensing standards.
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Affiliation(s)
- Qian Xu
- Department of the Built Environment, College of Design and Engineering, National University of Singapore, Singapore 119077, Singapore; (Q.X.); (H.C.G.)
| | - Hui Ci Goh
- Department of the Built Environment, College of Design and Engineering, National University of Singapore, Singapore 119077, Singapore; (Q.X.); (H.C.G.)
| | - Ehsan Mousavi
- Department of Construction Science and Management, Clemson University, Clemson, SC 29634, USA;
| | | | - Zubin Varghese
- Trane Technologies PLC Engineering & Technology Centre, Bangalore 560029, India; (Z.V.); (Y.P.)
| | - Yogesh Pandit
- Trane Technologies PLC Engineering & Technology Centre, Bangalore 560029, India; (Z.V.); (Y.P.)
| | - Ali Ghahramani
- Department of the Built Environment, College of Design and Engineering, National University of Singapore, Singapore 119077, Singapore; (Q.X.); (H.C.G.)
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18
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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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19
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Zhai F, Luo Y, Zhang Y, Liao S, Cheng J, Meng X, Zeng Y, Wang X, Yang J, Yin J, Li L. Viscosity Simulation of Glass Microfiber and an Unusual Air Filter with High-Efficiency Antibacterial Functionality Enabled by ZnO/Graphene-Modified Glass Microfiber. ACS OMEGA 2022; 7:14211-14221. [PMID: 35559200 PMCID: PMC9089376 DOI: 10.1021/acsomega.2c00838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/05/2022] [Indexed: 05/25/2023]
Abstract
The current global pandemic of new coronary pneumonia clearly reveals the importance of developing highly efficient filtration and fast germicidal performance of multifunctional air filters. In this study, a novel air filter with a controllable morphology based on the rod-like to flower-like zinc oxide/graphene-based photocatalytic composite particles loaded on glass microfiber was prepared by one-step microwave rapid synthesis. The multifunctional air filter shows the following special functions: the 10 mg·L-1 organic pollutant solution RhB was completely degraded within 2 h under a 500 W xenon lamp, and also 99% of Escherichia coli and Staphylococcus aureus were inactivated under a 60 W light-emitting diode lamp. Furthermore, after introducing the controllable morphology zinc oxide/graphene-based photocatalytic composite particles, the filtration efficiency of the multifunctional air filter was also kept at the same level (99.8%) as the one without any addition, indicating no loss of high-efficiency filtration while obtaining the rapid bactericidal function. The rapid antibacterial principle of the multifunctional air filter has also been proposed through the UV-vis spectroscopies, photoluminescence, and electron-spin resonance spectrum. The zinc oxide/graphene-based photocatalytic composite particles tightly coated on the glass microfiber surface could increase the active sites by changing the morphology of zinc oxide and, in the meantime, promote the separation of zinc oxide photo-generated electron-hole pairs to improve the rapid sterilization ability of the multifunctional air filters. In addition, an empirical formula to evaluate the relationship between the composition, viscosity, and viscosity modulus of glass microfiber was proposed by testing the viscosity of glass microfiber composed of 14 different compositions at 1300 and 1400 °C, which can be used as a criterion to evaluate the production technology of glass microfiber filters.
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Affiliation(s)
- Fuqiang Zhai
- Research
Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China
- Chongqing
Materials Research Institute Co., Ltd., Chongqing 400707, China
| | - Yongyi Luo
- School
of Materials and Energy, Southwest University, Chongqing 400715, China
| | - Yingchun Zhang
- College
of Pharmaceutical Sciences, Southwest University, Chongqing 402160, China
| | - Shichang Liao
- School
of Materials and Energy, Southwest University, Chongqing 400715, China
| | - Jiang Cheng
- Research
Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Xiang Meng
- Research
Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China
| | - Yue Zeng
- College
of Pharmaceutical Sciences, Southwest University, Chongqing 402160, China
| | - Xinhui Wang
- College
of Pharmaceutical Sciences, Southwest University, Chongqing 402160, China
| | - Jinming Yang
- Chongqing
Zisun Technology Co., Ltd., Chongqing 401120, China
| | - Jiaqi Yin
- Beijing
Aerospace Smart Manufacturing Technology Development Co., Ltd., Beijing 100144, China
| | - Lu Li
- Research
Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China
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20
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Ghaddar N, Ghali K. Ten questions concerning the paradox of minimizing airborne transmission of infectious aerosols in densely occupied spaces via sustainable ventilation and other strategies in hot and humid climates. BUILDING AND ENVIRONMENT 2022; 214:108901. [PMID: 35197667 PMCID: PMC8853966 DOI: 10.1016/j.buildenv.2022.108901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/07/2022] [Accepted: 02/12/2022] [Indexed: 05/14/2023]
Abstract
Airborne disease transmission in indoor spaces and resulting cross-contamination has been a topic of broad concern for years - especially recently with the outbreak of COVID-19. Global recommendations on this matter consist of increasing the outdoor air supply in the aim of diluting the indoor air. Nonetheless, a paradoxical relationship has risen between increasing amount of outdoor air and its impact on increased energy consumption - especially densely occupied spaces. The paradox is more critical in hot and humid climates, where large amounts of energy are required for the conditioning of the outdoor air. Therefore, many literature studies investigated new strategies for the mitigation of cross-contamination with little-to-no additional cost of energy. These strategies mainly consist of the dilution and/or the capture and removal of contaminants at the levels of macroenvironment room air and occupant-adjacent microenvironment. On the macroenvironment level, the dilution occurs by the supply of large amounts of outdoor air in a sustainable way using passive cooling systems, and the removal of contaminants happens via filtering. Similarly, the microenvironment of the occupant can be diluted using localized ventilation techniques, and contaminants can be captured and removed by direct exhaust near the source of contamination. Thus, this work answers ten questions that explore the most prevailing technologies from the above-mentioned fronts that are used to mitigate cross-contamination in densely occupied spaces located in hot and humid climates at minimal energy consumption. The paper establishes a basis for future work and insights for new research directives for macro and microenvironment approaches.
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Affiliation(s)
- Nesreen Ghaddar
- Mechanical Engineering Department, American University of Beirut, P.O. Box 11-0236, Beirut, 1107-2020, Lebanon
| | - Kamel Ghali
- Mechanical Engineering Department, American University of Beirut, P.O. Box 11-0236, Beirut, 1107-2020, Lebanon
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21
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Sheikhnejad Y, Aghamolaei R, Fallahpour M, Motamedi H, Moshfeghi M, Mirzaei PA, Bordbar H. Airborne and aerosol pathogen transmission modeling of respiratory events in buildings: An overview of computational fluid dynamics. SUSTAINABLE CITIES AND SOCIETY 2022; 79:103704. [PMID: 35070645 PMCID: PMC8767784 DOI: 10.1016/j.scs.2022.103704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 01/13/2022] [Accepted: 01/15/2022] [Indexed: 05/03/2023]
Abstract
Pathogen droplets released from respiratory events are the primary means of dispersion and transmission of the recent pandemic of COVID-19. Computational fluid dynamics (CFD) has been widely employed as a fast, reliable, and inexpensive technique to support decision-making and to envisage mitigatory protocols. Nonetheless, the airborne pathogen droplet CFD modeling encounters limitations due to the oversimplification of involved physics and the intensive computational demand. Moreover, uncertainties in the collected clinical data required to simulate airborne and aerosol transport such as droplets' initial velocities, tempo-spatial profiles, release angle, and size distributions are broadly reported in the literature. There is a noticeable inconsistency around these collected data amongst many reported studies. This study aims to review the capabilities and limitations associated with CFD modeling. Setting the CFD models needs experimental data of respiratory flows such as velocity, particle size, and number distribution. Therefore, this paper briefly reviews the experimental techniques used to measure the characteristics of airborne pathogen droplet transmissions together with their limitations and reported uncertainties. The relevant clinical data related to pathogen transmission needed for postprocessing of CFD data and translating them to safety measures are also reviewed. Eventually, the uncertainty and inconsistency of the existing clinical data available for airborne pathogen CFD analysis are scurtinized to pave a pathway toward future studies ensuing these identified gaps and limitations.
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Affiliation(s)
- Yahya Sheikhnejad
- Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, Universidade de Aveiro, Aveiro 3810-193, Portugal
- PICadvanced SA, Creative Science Park, Via do Conhecimento, Ed. Central, Ílhavo 3830-352, Portugal
| | - Reihaneh Aghamolaei
- School of Mechanical and Manufacturing Engineering, Faculty of Engineering and Computing, Dublin City University, Dublin 9, Whitehall, Ireland
| | - Marzieh Fallahpour
- School of Mechanical and Manufacturing Engineering, Faculty of Engineering and Computing, Dublin City University, Dublin 9, Whitehall, Ireland
| | - Hamid Motamedi
- Department of Mechanical Engineering, Tarbiat Modares University, Iran
| | - Mohammad Moshfeghi
- Department of Mechanical Engineering, Sogang University, Seoul, South Korea
| | - Parham A Mirzaei
- Architecture & Built Environment Department, University of Nottingham, University Park, Nottingham, UK
| | - Hadi Bordbar
- School of Engineering, Aalto University, Finland
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22
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Schnabel T, Dutschke M, Schuetz F, Hauser F, Springer C. Photocatalytic Air Purification of Polycyclic Aromatic Hydrocarbons: Application of a Flow-Through Reactor, Kinetic Studies and Degradation Pathways. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.113993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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Impact of natural ventilation on exposure to SARS-CoV 2 in indoor/semi-indoor terraces using CO 2 concentrations as a proxy. JOURNAL OF BUILDING ENGINEERING 2022; 46:103725. [PMCID: PMC8632854 DOI: 10.1016/j.jobe.2021.103725] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/20/2021] [Accepted: 11/19/2021] [Indexed: 06/16/2023]
Abstract
Nowadays, it is necessary a better airborne transmission understanding of respiratory diseases in shared indoor and semi-indoor environments with natural ventilation in order to adopt effective people's health protection measures. The aim of this work is to evaluate the relative exposure to SARS-CoV 2 in a set of virtual scenarios representing enclosed and semi-enclosed terraces under different outdoor meteorological conditions. For this purpose, indoor CO2 concentration is used as a proxy for the risk assessment. Airflow and people exhaled CO2 in different scenarios are simulated through Computational Fluid Dynamics (CFD) modelling with Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach. Both spatial average concentrations and local concentrations are analyzed. In general, spatial average concentrations decrease as ventilation increases, however, depending on the people arrangement inside the terrace, spatial average concentrations and local concentrations can be very different. Therefore, for assessing the relative exposure to SARS-CoV 2 it is necessary to consider the indoor flow patterns between infectors and susceptibles. This research provides detailed information about CO2 dispersion in enclosed/semi-enclosed scenarios, which can be very useful for reducing the transmission risk through better natural ventilation designs and improving the classic risk models since it allows to check their hypotheses in real-world scenarios. Although CFD ventilation studies in indoor/semi-indoor environments have been already addressed in the literature, this research is focused on restaurant terraces, scenarios scarcely investigated. Likewise, one of the novelties of this study is to take into account the outdoor meteorological conditions to appropriately simulate natural ventilation.
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24
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Shamim JA, Hsu WL, Daiguji H. Review of component designs for post-COVID-19 HVAC systems: Possibilities and challenges. Heliyon 2022; 8:e09001. [PMID: 35224237 PMCID: PMC8863315 DOI: 10.1016/j.heliyon.2022.e09001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/16/2021] [Accepted: 02/18/2022] [Indexed: 11/01/2022] Open
Abstract
The globally occurring recurrent waves of the COVID-19 pandemic, primarily caused by the transmission of aerosolized droplets from an infected person to a healthy person in the indoor environment, has led to the urgency of designing new modes of indoor ventilation. To prevent cross-contaminations due to airborne viruses, bacteria, and other pollutants in indoor environments, heating ventilation and air-conditioning (HVAC) systems need to be redesigned with anti-pandemic components. The three vital anti-pandemic components for the post-COVID-19 HVAC systems, as identified by the authors, are: a biological contaminant inactivation unit, a volatile organic compound decomposition unit, and an advanced air filtration unit. The purpose of the current article is to provide an overview of the latest research outcomes toward designing these anti-pandemic components and pointing out the future promises and challenges. In addition, the role of personalized ventilation in minimizing the risk of indoor cross-contamination by employing various air terminal devices is discussed. The authors believe that this article will encourage HVAC designers to develop effective anti-pandemic components to minimize the indoor airborne transmission.
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Affiliation(s)
- Jubair A Shamim
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Wei-Lun Hsu
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hirofumi Daiguji
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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Song L, Zhou J, Wang C, Meng G, Li Y, Jarin M, Wu Z, Xie X. Airborne pathogenic microorganisms and air cleaning technology development: A review. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127429. [PMID: 34688006 DOI: 10.1016/j.jhazmat.2021.127429] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Transmission of pathogens through air is a critical pathway for the spread of airborne diseases, as airborne pathogenic microorganisms cause several harmful infections. This review summarizes the occurrence, transmission, and adverse impacts of airborne pathogenic microorganisms that spread over large distances via bioaerosols. Air cleaning technologies have demonstrated great potential to prevent and reduce the spread of airborne diseases. The recent advances in air cleaning technologies are summarized on the basis of their advantages, disadvantages, and adverse health effects with regard to the inactivation mechanisms. The application scope and energy consumption of different technologies are compared, and the characteristics of air cleaners in the market are discussed. The development of high-efficiency, low-cost, dynamic air cleaning technology is identified as the leading research direction of air cleaning. Furthermore, future research perspectives are discussed and further development of current air cleaning technologies is proposed.
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Affiliation(s)
- Lu Song
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, PR China; School of Environmental Science and Engineering, Tianjin University, Tianjin, PR China
| | - Jianfeng Zhou
- School of Civil and Environmental Engineering, Georgia Institute of Technology, GA, USA
| | - Can Wang
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, PR China; School of Environmental Science and Engineering, Tianjin University, Tianjin, PR China.
| | - Ge Meng
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, PR China; School of Environmental Science and Engineering, Tianjin University, Tianjin, PR China
| | - Yunfei Li
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, PR China; School of Environmental Science and Engineering, Tianjin University, Tianjin, PR China
| | - Mourin Jarin
- School of Civil and Environmental Engineering, Georgia Institute of Technology, GA, USA
| | - Ziyan Wu
- School of Civil and Environmental Engineering, Georgia Institute of Technology, GA, USA
| | - Xing Xie
- School of Civil and Environmental Engineering, Georgia Institute of Technology, GA, USA.
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Vlaskin MS. Review of air disinfection approaches and proposal for thermal inactivation of airborne viruses as a life-style and an instrument to fight pandemics. APPLIED THERMAL ENGINEERING 2022; 202:117855. [PMID: 34867067 PMCID: PMC8628600 DOI: 10.1016/j.applthermaleng.2021.117855] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/20/2021] [Accepted: 11/24/2021] [Indexed: 05/02/2023]
Abstract
COVID-19 (Coronavirus Disease 2019) pandemic highlighted the importance of air biosecurity because SARS-CoV-2 is mainly transmitted from person to person via airborne droplets. Preventing infectious droplets from entering the body is one of the best ways to protect against infection. This paper reviews the transmission patterns of airborne pathogens and air disinfection methods. A particular emphasis is put on studies devoted to the thermal inactivation of viruses. These reviews reveal that air heat treatment has not been seriously considered as a possible air disinfection approach. Simple calculations show that the energy input required for thermal disinfection of human's air daily consumption is almost the same as for daily water consumption (by heat treatment from room temperature to 100 °C). Moreover, it is possible to organize a continuous heat recovery from the air already heated during disinfection to the inlet air, thus significantly increasing the energy efficiency. Therefore, I propose a solution for the thermal inactivation of airborne pathogens based on air heating and its subsequent cooling in a heat exchanger with heat recovery. Such a solution could be used to create mobile personal and stationary indoor air disinfectors, as well as heating, ventilation, and air conditioning systems. Thermal disinfection of air to breathe might one day be part of people's daily life like thermal disinfection of drinking water. Aside from limiting infectious disease transmission, thermal inactivation might be the basis for developing inhaled vaccines using thermally inactivated whole pathogens.
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Affiliation(s)
- Mikhail S Vlaskin
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 13/2 Izhorskaya St, Moscow 125412, Russia
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27
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Formulation and evaluation of surface-fluorinated microsized-TiO2 based self-cleaning cement: characterization, self-cleaning, depollution and antimicrobial study. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02093-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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28
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Xu C, Liu W, Luo X, Huang X, Nielsen PV. Prediction and control of aerosol transmission of SARS-CoV-2 in ventilated context: from source to receptor. SUSTAINABLE CITIES AND SOCIETY 2022; 76:103416. [PMID: 34611508 PMCID: PMC8484231 DOI: 10.1016/j.scs.2021.103416] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 05/24/2023]
Abstract
Global spread of COVID-19 has seriously threatened human life and health. The aerosol transmission route of SARS-CoV-2 is observed often associated with infection clusters under poorly ventilated environment. In the context of COVID-19 pandemic, significant transformation and optimization of traditional ventilation systems are needed. This paper is aimed to offer better understanding and insights into effective ventilation design to maximize its ability in airborne risk control, for particularly the COVID-19. Comprehensive reviews of each phase of aerosol transmission of SARS-CoV-2 from source to receptor are conducted, so as to provide a theoretical basis for risk prediction and control. Infection risk models and their key parameters for risk assessment of SARS-CoV-2 are analyzed. Special focus is given on the efficacy of different ventilation strategies in mitigating airborne transmission. Ventilation interventions are found mainly impacting on the dispersion and inhalation phases of aerosol transmission. The airflow patterns become a key factor in controlling the aerosol diffusion and distribution. Novel and personalized ventilation design, effective integration with other environmental control techniques and resilient HVAC system design to adapt both common and epidemic conditions are still remaining challenging, which need to be solved with the aid of multidisciplinary research and intelligent technologies.
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Affiliation(s)
- Chunwen Xu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Wenbing Liu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Xilian Luo
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xingyu Huang
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Peter V Nielsen
- Division of Sustainability, Energy and Indoor Environment, Aalborg University, Aalborg 9000, Denmark
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Singer BC, Zhao H, Preble CV, Delp WW, Pantelic J, Sohn MD, Kirchstetter TW. Measured influence of overhead HVAC on exposure to airborne contaminants from simulated speaking in a meeting and a classroom. INDOOR AIR 2022; 32:e12917. [PMID: 34477251 DOI: 10.1111/ina.12917] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/08/2021] [Accepted: 07/11/2021] [Indexed: 06/13/2023]
Abstract
Tracer gas experiments were conducted in a 158 m3 room with overhead supply diffusers to study dispersion of contaminants from simulated speaking in physically distanced meeting and classroom configurations. The room was contained within a 237 m3 cell with open plenum return to the HVAC system. Heated manikins at desks and a researcher operating the tracer release apparatus presented 8-9 thermal plumes. Experiments were conducted under conditions of no forced air and neutral, cooled, or heated air supplied at 980-1100 cmh, and with/out 20% outdoor air. CO2 was released at the head of one manikin in each experiment to simulate small (<5 µm diameter) respiratory aerosols. The metric of exposure relative to perfectly mixed (ERM) is introduced to quantify impacts, based on measurements at manikin heads and at three heights in the center and corners of the room. Chilled or neutral supply air provided good mixing with ERMs close to one. Thermal stratification during heating produced higher ERMs at most manikins: 25% were ≥2.5 and the highest were >5× perfectly mixed conditions. Operation of two within-zone air cleaners together moving ≥400 cmh vertically in the room provided enough mixing to mitigate elevated exposure variations.
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Affiliation(s)
- Brett C Singer
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Haoran Zhao
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Chelsea V Preble
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- Department of Civil & Environmental Engineering, University of California, Berkeley, California, USA
| | - William W Delp
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Jovan Pantelic
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- Center for the Built Environment, University of California, Berkeley, California, USA
| | - Michael D Sohn
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Thomas W Kirchstetter
- Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- Department of Civil & Environmental Engineering, University of California, Berkeley, California, USA
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30
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Li Y, Cheng P, Jia W. Poor ventilation worsens short-range airborne transmission of respiratory infection. INDOOR AIR 2022; 32:e12946. [PMID: 34704625 PMCID: PMC8652937 DOI: 10.1111/ina.12946] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 08/31/2021] [Accepted: 10/12/2021] [Indexed: 05/20/2023]
Abstract
To explain the observed phenomenon that most SARS-CoV-2 transmission occurs indoors whereas its outdoor transmission is rare, a simple macroscopic aerosol balance model is developed to link short- and long-range airborne transmission. The model considers the involvement of exhaled droplets with initial diameter ≤50 µm in the short-range airborne route, whereas only a fraction of these droplets with an initial diameter within 15 µm or equivalently a final diameter within 5 µm considered in the long-range airborne route. One surprising finding is that the room ventilation rate significantly affects the short-range airborne route, in contrast to traditional belief. When the ventilation rate in a room is insufficient, the airborne infection risks due to both short- and long-range transmission are high. A ventilation rate of 10 L/s per person provides a similar concentration vs distance decay profile to that in outdoor settings, which provides additional justification for the widely adopted ventilation standard of 10 L/s per person. The newly obtained data do not support the basic assumption in the existing ventilation standard ASHRAE 62.1 (2019) that the required people outdoor air rate is constant if the standard is used directly for respiratory infection control. Instead, it is necessary to increase the ventilation rate when the physical distance between people is less than approximately 2 m.
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Affiliation(s)
- Yuguo Li
- Department of Mechanical EngineeringThe University of Hong KongHong Kong SARChina
| | - Pan Cheng
- Department of Mechanical EngineeringThe University of Hong KongHong Kong SARChina
| | - Wei Jia
- Department of Mechanical EngineeringThe University of Hong KongHong Kong SARChina
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Liu W, Liu L, Xu C, Fu L, Wang Y, Nielsen PV, Zhang C. Exploring the potentials of personalized ventilation in mitigating airborne infection risk for two closely ranged occupants with different risk assessment models. ENERGY AND BUILDINGS 2021; 253:111531. [PMID: 34611376 PMCID: PMC8483985 DOI: 10.1016/j.enbuild.2021.111531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/20/2021] [Accepted: 09/28/2021] [Indexed: 05/15/2023]
Abstract
In the context of COVID-19, new requirements are occurring in ventilation systems to mitigate airborne transmission risk in indoor environment. Personalized ventilation (PV) which directly delivers clean air to the occupant's breathing zone is considered as a promising solution. To explore the potentials of PV in preventing the spread of infectious aerosols between closely ranged occupants, experiments were conducted with two breathing thermal manikins with three different relative orientations. Nebulized aerosols were used to mimic exhaled droplets transmitted between the occupants. Four risk assessment models were applied to evaluate the exposure or infection risk affected by PV with different operation modes. Results show that PV was effective in reducing the user's infection risk compared with mixing ventilation alone. Relative orientations and operation modes of PV significantly affected its performance in airborne risk control. The infection risk of SARS-CoV-2 was reduced by 65% with PV of 9 L/s after an exposure duration of 2 h back-to-back as assessed by the dose-response model, indicating effective protection effect of PV against airborne transmission. While the side-by-side orientation was found to be the most critical condition for PV in airborne risk control as it would accelerate diffusion of infectious droplets in lateral diffusion to occupants by side. Optimal designs of PV for closely ranged occupants were hereby discussed. The four risk assessment models were compared and validated by experiments with PV, implying basically consistent rules of the predicted risk with PV among the four models. The relevance and applicability of these models were discussed to provide a basis for risk assessment with non-uniformly distributed pathogens indoor.
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Affiliation(s)
- Wenbing Liu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Li Liu
- Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an 710055, China
- Laboratory of Eco-Planning & Green Building, Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Chunwen Xu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Linzhi Fu
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an 710055, China
| | - Yi Wang
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an 710055, China
| | - Peter V Nielsen
- Division of Sustainability, Energy and Indoor Environment, Aalborg University, Aalborg 9000, Denmark
| | - Chen Zhang
- Division of Sustainability, Energy and Indoor Environment, Aalborg University, Aalborg 9000, Denmark
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Ahmadi Y, Bhardwaj N, Kim KH, Kumar S. Recent advances in photocatalytic removal of airborne pathogens in air. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148477. [PMID: 34198079 DOI: 10.1016/j.scitotenv.2021.148477] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/31/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
The abatement of airborne pathogens such as bacteria, viruses, and fungi has become an important goal of air-quality management. Efficient and effective treatment techniques such as photocatalysis are essential for disinfection of airborne microorganisms. This review focuses on recent advances in the formulation and development of photocatalytic disinfection, design of efficient photocatalysts, choice of photocatalytic reactor, removal and/or disinfection mechanisms, and the role of reactive ion species. Data from recent studies are analyzed to accurately assess the efficacy of such disinfection approaches. This review also highlights the application of innovative materials in individual and combined abatement systems against airborne bacterial, viral, and fungal pathogens. We discuss the efficiency and benefits presented by such systems, address the challenges, and provide a perspective for future research.
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Affiliation(s)
- Younes Ahmadi
- Department of Analytical Chemistry, Kabul University, Kabul 1001, Afghanistan
| | - Neha Bhardwaj
- Department of Biotechnology, University Institute of Engineering Technology (UIET), Panjab University, Chandigarh, India
| | - Ki-Hyun Kim
- Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Republic of Korea.
| | - Sandeep Kumar
- Department of Bio and Nano Technology, Guru Jambheshwar University of Science and Technology, Hisar, Haryana 125001, India.
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Bu Y, Ooka R, Kikumoto H, Oh W. Recent research on expiratory particles in respiratory viral infection and control strategies: A review. SUSTAINABLE CITIES AND SOCIETY 2021; 73:103106. [PMID: 34306994 PMCID: PMC8272400 DOI: 10.1016/j.scs.2021.103106] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 06/07/2021] [Accepted: 06/15/2021] [Indexed: 05/15/2023]
Abstract
The global spread of coronavirus disease 2019 poses a significant threat to human health. In this study, recent research on the characteristics of expiratory particles and flow is reviewed, with a special focus on different respiratory activities, to provide guidance for reducing the viral infection risk in the built environment. Furthermore, environmental influence on particle evaporation, dispersion, and virus viability after exhalation and the current methods for infection risk assessment are reviewed. Finally, we summarize promising control strategies against infectious expiratory particles. The results show that airborne transmission is a significant viral transmission route, both in short and long ranges, from infected individuals. Relative humidity affects the evaporation and trajectories of middle-sized droplets most, and temperature accelerates the inactivation of SARS-CoV-2 both on surfaces and in aerosols. Future research is needed to improve infection risk models to better predict the infection potential of different transmission routes. Moreover, further quantitative studies on the expiratory flow features after wearing a mask are needed. Systematic investigations and the design of advanced air distribution methods, portable air cleaners, and ultraviolet germicidal irradiation systems, which have shown high efficacy in removing contaminants, are required to better control indoor viral infection.
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Affiliation(s)
- Yunchen Bu
- Graduate School of Engineering, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Ryozo Ooka
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Hideki Kikumoto
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Wonseok Oh
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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Evaluation of Antimicrobial Effect of Zinc Pyrithione against Airborne Fungi and Bacteria Growth Collected onto New and Loaded HVAC Fibrous Filters. Processes (Basel) 2021. [DOI: 10.3390/pr9091528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Microbial growth onto HVAC filters was observed in real conditions with possible degradation of the indoor air quality. The filtration performance of marketed antimicrobial filters containing zinc pyrithione was tested under laboratory conditions and compared to that of similar filters with the same classification, F7 (EN779:2002). The filtration performance of the two tested filters during loading with PM10 particles was quantified in an experimental setup with filter pressure drop measurement and particle counting upstream and downstream of the filters. The microbial growth on the new and loaded filters, both contaminated with a microbial airborne consortium composed of two bacteria (Gram-positive and -negative) and fungi, was quantified by colony-forming units after conditioning the filters for a few days under controlled temperature (25 °C) and humidity (50% or 90% relative humidity). The results reveal that there was no degradation of the filtration performance of the filters treated with the antimicrobial agent. The efficiency of the antimicrobial treatment, i.e., the ability to inhibit the growth of microorganisms during the incubation period, was significant with the new filters regarding the fungal growth, but the results demonstrate that the antimicrobial treatment became inefficient with the loaded filters.
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COVID-19 Impact on Operation and Energy Consumption of Heating, Ventilation and Air-Conditioning (HVAC) Systems. ADVANCES IN APPLIED ENERGY 2021; 3. [PMCID: PMC8166037 DOI: 10.1016/j.adapen.2021.100040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Heating, ventilation and air-conditioning (HVAC) system is favourable for regulating indoor temperature, relative humidity, airflow pattern and air quality. However, HVAC systems may turn out to be the culprit of microbial contamination in enclosed spaces and deteriorate the environment due to inappropriate design and operation. In the context of COVID-19, significant transformations and new requirements are occurring in HVAC systems. Recently, several updated operational guidelines for HVAC systems have been issued by various institutions to control the airborne transmission and mitigate infection risks in enclosed environments. Challenges and innovations emerge in response to operational variations of HVAC systems. To efficiently prevent the spread of the pandemic and reduce infection risks, it is essential to have an overall understanding of impacts caused by COVID-19 on HVAC systems. Therefore, the objectives of this article are to: (a) provide a comprehensive review of the airborne transmission characteristics of SARS-CoV-2 in enclosed spaces and a theoretical basis for HVAC operation guideline revision; (b) investigate HVAC-related guidelines to clarify the operational variations of HVAC systems during the pandemic; (c) analyse how operational variations of HVAC systems affect energy consumption; and (d) identify the innovations and research trends concerning future HVAC systems. Furthermore, this paper compares the energy consumption of HVAC system operation during the normal times versus pandemic period, based on a case study in China, providing a reference for other countries around the world. Results of this paper offer comprehensive insights into how to keep indoor environments safe while maintaining energy-efficient operation of HVAC systems.
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Key Words
- energy impacts of hvac systems
- covid-19 pandemic
- airborne transmission
- hvac operation guidelines
- challenges and innovations
- ahu, air handing unit
- asc, architectural society of china
- ashrae, american society of heating refrigerating and air-conditioning engineers
- car, chinese association of refrigeration
- cciaq, canadian committee on indoor air quality
- cop, coefficient of performance
- dcv, demand-controlled ventilation
- ecdc, european centre for disease prevention and control
- eeaf, electrostatic enhanced air filter
- eepf, electrostatic enhanced pleated air filters
- hepa, high efficiency particulate air
- hphe, heat pipe heat exchanger
- epa, environmental protection agency
- hvac, heating, ventilation and air-conditioning
- ishrae, indian society of heating refrigerating and air conditioning engineers
- merv, minimum efficiency reporting value
- mohurd, ministry of housing and urban-rural development of the people's republic of china
- nhc, national health commission of china
- pho, public health ontario
- rehva, federation of european heating ventilation and air conditioning associations
- sac, standardization administration of the people's republic of china
- sbs, sick building syndrome
- shase, society of heating air-conditioning and sanitary engineers in japan
- uv, ultraviolet
- uvgi, ultraviolet germicidal irradiation
- who, world health organization
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Elsaid AM, Ahmed MS. Indoor Air Quality Strategies for Air-Conditioning and Ventilation Systems with the Spread of the Global Coronavirus (COVID-19) Epidemic: Improvements and Recommendations. ENVIRONMENTAL RESEARCH 2021; 199:111314. [PMID: 34048748 PMCID: PMC8146370 DOI: 10.1016/j.envres.2021.111314] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/06/2021] [Indexed: 05/08/2023]
Abstract
The coronavirus has come to the world and spread with great wide among the countries of the world and has resulted in numerous infections that exceeded 167,181,023 million patients and are close to 3.5 deaths by September 2021. It also brought with it panic and fear, halted many activities, and led to the decline of the global economy. It changed human behavior and forced people to change their lifestyles to avoid infection. One of the most sectors that must be taken into consideration through pandemic coronavirus (COVID-19) around the globe is the air conditioning systems. The HVAC systems depend on the air as a heat transfer medium. The air contains a group of pollutants, viruses, and bacteria, and it affects and destroys human life. The air filter plays a major role as an important component in the air conditioning systems. Thus, it requires more effort by researchers to improve its design to prevent the ultra-size of particles loaded with coronavirus (COVID-19). This paper provides insight into the design of existing combined air-conditioners on their suitability and their impact on the spread of the hybrid coronavirus epidemic and review efforts to obtain a highly efficient air filter to get rid of super-sized particles for protection against epidemic infection. In addition, important guideline recommendations have been made to limit the spread of the COVID-19 virus and to obtain indoor air quality in air-conditioned places.
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Affiliation(s)
- Ashraf Mimi Elsaid
- RHVAC Department of Technology, Faculty of Technology and Education, Helwan University, Cairo, 11282, Egypt.
| | - M Salem Ahmed
- Mechanical Power Engineering Department, Faculty of Technology and Education, Sohag University, Egypt
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Zafarnejad R, Griffin PM. Assessing school-based policy actions for COVID-19: An agent-based analysis of incremental infection risk. Comput Biol Med 2021; 134:104518. [PMID: 34102403 PMCID: PMC8163694 DOI: 10.1016/j.compbiomed.2021.104518] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/13/2021] [Accepted: 05/24/2021] [Indexed: 02/07/2023]
Abstract
Many schools and universities have seen a significant increase in the spread of COVID-19. As such, a number of non-pharmaceutical interventions have been proposed including distancing requirements, surveillance testing, and updating ventilation systems. Unfortunately, there is limited guidance for which policy or set of policies are most effective for a specific school system. We develop a novel approach to model the spread of SARS-CoV-2 quanta in a closed classroom environment that extends traditional transmission models that assume uniform mixing through air recirculation by including the local spread of quanta from a contagious source. In addition, the behavior of students with respect to guideline compliance was modeled through an agent-based simulation. Estimated infection rates were on average lower using traditional transmission models compared to our approach. Further, we found that although ventilation changes were effective at reducing mean transmission risk, it had much less impact than distancing practices. Duration of the class was an important factor in determining the transmission risk. For the same total number of semester hours for a class, delivering lectures more frequently for shorter durations was preferable to less frequently with longer durations. Finally, as expected, as the contact tracing level increased, more infectious students were identified and removed from the environment and the spread slowed, though there were diminishing returns. These findings can help provide guidance as to which school-based policies would be most effective at reducing risk and can be used in a cost/comparative effectiveness estimation study given local costs and constraints.
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Burridge HC, Bhagat RK, Stettler MEJ, Kumar P, De Mel I, Demis P, Hart A, Johnson-Llambias Y, King MF, Klymenko O, McMillan A, Morawiecki P, Pennington T, Short M, Sykes D, Trinh PH, Wilson SK, Wong C, Wragg H, Davies Wykes MS, Iddon C, Woods AW, Mingotti N, Bhamidipati N, Woodward H, Beggs C, Davies H, Fitzgerald S, Pain C, Linden PF. The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime. Proc Math Phys Eng Sci 2021; 477:20200855. [PMID: 35153550 PMCID: PMC8300604 DOI: 10.1098/rspa.2020.0855] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/10/2021] [Indexed: 12/23/2022] Open
Abstract
The year 2020 has seen the emergence of a global pandemic as a result of the disease COVID-19. This report reviews knowledge of the transmission of COVID-19 indoors, examines the evidence for mitigating measures, and considers the implications for wintertime with a focus on ventilation.
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Affiliation(s)
- Henry C. Burridge
- Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, South Kensington Campus, London SW7 2AZ, UK
| | - Rajesh K. Bhagat
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
| | - Marc E. J. Stettler
- Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, South Kensington Campus, London SW7 2AZ, UK
| | - Prashant Kumar
- Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, University of Surrey, Stag Hill, Guildford GU2 7XH, UK
| | - Ishanki De Mel
- Department of Chemical and Process Engineering, University of Surrey, Stag Hill, Guildford GU2 7XH, UK
| | - Panagiotis Demis
- Department of Chemical and Process Engineering, University of Surrey, Stag Hill, Guildford GU2 7XH, UK
| | - Allen Hart
- Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | | | | | - Oleksiy Klymenko
- Department of Chemical and Process Engineering, University of Surrey, Stag Hill, Guildford GU2 7XH, UK
| | - Alison McMillan
- Prifysgol Glyndŵr Wrecsam, Ffordd yr Wyddgrug, Wrecsam LL11 2AW: Wrexham Glyndŵr University, Mold Road, Wrexham LL11 2AW, UK
| | - Piotr Morawiecki
- Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Thomas Pennington
- Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Michael Short
- Department of Chemical and Process Engineering, University of Surrey, Stag Hill, Guildford GU2 7XH, UK
| | - David Sykes
- AEROS Consultancy, 35 Nairn St, Glasgow G3 8SE, UK
| | - Philippe H. Trinh
- Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Stephen K. Wilson
- Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK
| | - Clint Wong
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - Hayley Wragg
- Department of Mathematical Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Megan S. Davies Wykes
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
| | - Chris Iddon
- Chartered Institution of Building Services Engineers, 222 Balham High Road, London SW12 9BS, UK
| | - Andrew W. Woods
- BP Institute for Multiphase Flow, University of Cambridge, Madingley Rd, Cambridge CB3 0EZ, UK
| | - Nicola Mingotti
- BP Institute for Multiphase Flow, University of Cambridge, Madingley Rd, Cambridge CB3 0EZ, UK
| | - Neeraja Bhamidipati
- BP Institute for Multiphase Flow, University of Cambridge, Madingley Rd, Cambridge CB3 0EZ, UK
| | - Huw Woodward
- Centre for Environmental Policy, Imperial College London, London SW7 2AZ, UK
| | - Clive Beggs
- Carnegie School of Sport, Headingley Campus, Leeds Beckett University, Leeds LS6 3QT, UK
| | - Hywel Davies
- Chartered Institution of Building Services Engineers, 222 Balham High Road, London SW12 9BS, UK
| | - Shaun Fitzgerald
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
| | - Christopher Pain
- Department of Earth Science and Engineering, Imperial College London, Royal School of Mines, South Kensington Campus, London SW7 2AZ, UK
| | - P. F. Linden
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
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Dbouk T, Drikakis D. Fluid dynamics and epidemiology: Seasonality and transmission dynamics. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:021901. [PMID: 33746486 PMCID: PMC7976049 DOI: 10.1063/5.0037640] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 12/17/2020] [Indexed: 05/04/2023]
Abstract
Epidemic models do not account for the effects of climate conditions on the transmission dynamics of viruses. This study presents the vital relationship between weather seasonality, airborne virus transmission, and pandemic outbreaks over a whole year. Using the data obtained from high-fidelity multi-phase, fluid dynamics simulations, we calculate the concentration rate of Coronavirus particles in contaminated saliva droplets and use it to derive a new Airborne Infection Rate (AIR) index. Combining the simplest form of an epidemiological model, the susceptible-infected-recovered, and the AIR index, we show through data evidence how weather seasonality induces two outbreaks per year, as it is observed with the COVID-19 pandemic worldwide. We present the results for the number of cases and transmission rates for three cities, New York, Paris, and Rio de Janeiro. The results suggest that two pandemic outbreaks per year are inevitable because they are directly linked to what we call weather seasonality. The pandemic outbreaks are associated with changes in temperature, relative humidity, and wind speed independently of the particular season. We propose that epidemiological models must incorporate climate effects through the AIR index.
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Megahed NA, Ghoneim EM. Indoor Air Quality: Rethinking rules of building design strategies in post-pandemic architecture. ENVIRONMENTAL RESEARCH 2021; 193:110471. [PMID: 33197423 PMCID: PMC7661949 DOI: 10.1016/j.envres.2020.110471] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/20/2020] [Accepted: 11/09/2020] [Indexed: 05/20/2023]
Abstract
To effectively reduce the spread of SARS-CoV-2, it is crucial to highlight the effectiveness of building design strategies in mitigating threats to occupants. The ongoing pandemic research and actions focus on how poor Indoor Air Quality (IAQ) amplifies the effects of airborne viruses. This review aims to draw architects' attention toward the high risk of airborne transmission of diseases by providing the latest updates and solutions to understand better the environmental and health issues associated with COVID-19. Based on the complexity of the problem and the need for interdisciplinary research, this study presents a conceptual model that addresses the integration of engineering controls, design strategies and, air disinfection techniques required to achieve a better IAQ.
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Affiliation(s)
- Naglaa A Megahed
- Professor, Architecture and Urban Planning Department, Faculty of Engineering, Port Said University, Egypt.
| | - Ehab M Ghoneim
- Professor of Ophthalmology, Vice Dean for Community Services & Environmental Development Affairs, Faculty of Medicine, Port Said University, Egypt.
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Sengun IY, Senturk S, Gul S, Kilic G. Potential of essential oil combinations for surface and air disinfection. Lett Appl Microbiol 2021; 72:526-534. [PMID: 33377499 DOI: 10.1111/lam.13445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 11/29/2022]
Abstract
In this study, it was aimed to develop a novel disinfectant from various essential oils containing active components with antimicrobial activity. The mixture of oregano, cinnamon and clove oils (1 : 1 : 1) with 10% oil concentration (SOM) was used as potential disinfectant on various areas and showed the highest antimicrobial activity among oil combinations tested. SOM reduced the numbers of total mesophilic aerobic bacteria (TMAB; 2·27 log CFU per 25 cm2 ) and Escherichia coli (4·60 log CFU per 25 cm2 ) under the detection limits. Application of SOM (1, 2, 3, 4 and 6%) into incubators reduced TMAB and mould-yeast counts of incubator air by 82·9 and 100% respectively. SOM application (3%) into ambient air also reduced its TMAB and mould-yeast counts by 92 and 84·6% respectively. While ethanol is commonly used for the disinfection of environments, equipment and surfaces, SOM is an important alternative that may also be used for the disinfection of various surfaces as well as air.
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Affiliation(s)
- I Y Sengun
- Food Engineering Department, Engineering Faculty, Ege University, Bornova, Izmir, Turkey
| | - S Senturk
- Food Engineering Department, Engineering Faculty, Ege University, Bornova, Izmir, Turkey
| | - S Gul
- Food Engineering Department, Engineering Faculty, Ege University, Bornova, Izmir, Turkey
| | - G Kilic
- Food Engineering Department, Engineering Faculty, Ege University, Bornova, Izmir, Turkey
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42
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Saxena A, Khare D, Agrawal S, Singh A, Dubey AK. Recent advances in materials science: a reinforced approach toward challenges against COVID-19. EMERGENT MATERIALS 2021; 4:57-73. [PMID: 33644691 PMCID: PMC7898028 DOI: 10.1007/s42247-021-00179-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 01/27/2021] [Indexed: 05/15/2023]
Abstract
With the recent COVID-19 pandemic, medical professionals and scientists have encountered an unprecedented trouble to make the latest technological solutions to work. Despite of abundant tools available as well as initiated for diagnosis and treatment, researchers in the healthcare systems were in backfoot to provide concrete answers to the demanding challenge of SARS-CoV-2. It has incited global collaborative efforts in every field from economic, social, and political to dedicated science to confront the growing demand toward solution to this outbreak. Field of materials science has been in the frontline to the current scenario to provide major diagnostic tools, antiviral materials, safety materials, and various therapeutic means such as, antiviral drug design, drug delivery, and vaccination. In the present article, we emphasized the role of materials science to the development of PPE kits such as protecting suits, gloves, and masks as well as disinfection of the surfaces/surroundings. In addition, contribution of materials science towards manufacturing diagnostic devices such as microfluidics, immunosensors as well as biomaterials with a point of care analysis has also been discussed. Further, the efficacy of nanoparticles and scaffolds for antiviral drug delivery and micro-physiological systems as well as materials derived from human tissues for extracorporeal membrane oxygenation (ECMO) devices have been elaborated towards therapeutic applications.
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Affiliation(s)
- Abhinav Saxena
- Department of Ceramic Engineering, Indian Institute of Technology (Banaras Hindu University), -221005, Varanasi, India
| | - Deepak Khare
- Department of Ceramic Engineering, Indian Institute of Technology (Banaras Hindu University), -221005, Varanasi, India
| | - Swati Agrawal
- Department of Ceramic Engineering, Indian Institute of Technology (Banaras Hindu University), -221005, Varanasi, India
| | - Angaraj Singh
- Department of Ceramic Engineering, Indian Institute of Technology (Banaras Hindu University), -221005, Varanasi, India
| | - Ashutosh Kumar Dubey
- Department of Ceramic Engineering, Indian Institute of Technology (Banaras Hindu University), -221005, Varanasi, India
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43
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Ren YF, Huang Q, Marzouk T, Richard R, Pembroke K, Martone P, Venner T, Malmstrom H, Eliav E. Effects of mechanical ventilation and portable air cleaner on aerosol removal from dental treatment rooms. J Dent 2020; 105:103576. [PMID: 33388387 PMCID: PMC7834919 DOI: 10.1016/j.jdent.2020.103576] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/23/2020] [Accepted: 12/26/2020] [Indexed: 01/10/2023] Open
Abstract
Objectives To evaluate the mechanical ventilation rates of dental treatment rooms and assess the effectiveness of aerosol removal by mechanical ventilation and a portable air cleaner (PAC) with a high-efficiency particulate air (HEPA) filter. Methods Volumetric airflow were measured to assess air change rate per hour by ventilation (ACHvent). Equivalent ventilation provided by the PAC (ACHpac) was calculated based on its clean air delivery rate. Concentrations of 0.3, 0.5 and 1.0 μm aerosol particles were measured in 10 dental treatment rooms with various ventilation rates at baseline, after 5-min of incense burn, and after 30-min of observation with and without the PAC or ventilation system in operation. Velocities of aerosol removal were assessed by concentration decay constants for the 0.3 μm particles with ventilation alone (Kn) and with ventilation and PAC (Kn+pac), and by times needed to reach 95 % and 100 % removal of accumulated aerosol particles. Results ACHvent varied from 3 to 45. Kn and Kn+pac were correlated with ACHvent (r = 0.90) and combined ACHtotal (r = 0.81), respectively. Accumulated aerosol particles could not be removed by ventilation alone within 30-min in rooms with ACHvent<15. PAC reduced aerosol accumulation and accelerated aerosol removal, and accumulated aerosols could be completely removed in 4 to 12-min by ventilation combined with PAC. Effectiveness of the PAC was especially prominent in rooms with poor ventilation. Added benefit of PAC in aerosol removal was inversely correlated with ACHvent. Conclusions Aerosol accumulation may occur in dental treatment rooms with poor ventilation. Addition of PAC with a HEPA filter significantly reduced aerosol accumulation and accelerated aerosol removal. Clinical significance Addition of PAC with a HEPA filter improves aerosol removal in rooms with low ventilation rates.
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Affiliation(s)
- Yan-Fang Ren
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA.
| | - Qirong Huang
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA
| | - Tamer Marzouk
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA
| | - Ray Richard
- Facility Operations, University of Rochester Medical Center, Rochester, New York, USA
| | - Karen Pembroke
- Facility Operations, University of Rochester Medical Center, Rochester, New York, USA
| | - Pat Martone
- Facility Operations, University of Rochester Medical Center, Rochester, New York, USA
| | - Tom Venner
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA
| | - Hans Malmstrom
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA
| | - Eli Eliav
- Eastman Institute for Oral Health, University of Rochester Medical Center, Rochester, New York, USA
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44
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Sutton D, Bertozzi-Villa C, Lasky J, Fuchs K, Friedman A. Outcomes and epidemiology of COVID-19 infection in the obstetric population. Semin Perinatol 2020; 44:151283. [PMID: 32798094 PMCID: PMC7371575 DOI: 10.1016/j.semperi.2020.151283] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
As of June 19, 2020 there are more than 8.6 million COVID-19 cases worldwide with over 450,000 deaths. Providing obstetrical care in the setting of the pandemic poses challenges to the healthcare system in that, in comparison to many other medical specialties, obstetrical care cannot be deferred. Pregnant patients represent a high risk population for exposure and infection with respiratory pathogens and, as they require multiple points of contact with the healthcare system, are especially vulnerable. The purpose of this review is assess current epidemiology and outcomes research related to COVID-19 with a focus on obstetric patients. This review covers the global spread of the SARS-CoV-2 virus, symptomatology, modes of transmission, and current knowledge gaps related to epidemiology and outcomes for the obstetric population.
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Affiliation(s)
- Desmond Sutton
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, NewYork-Presbyterian Hospital/Columbia University Irving Medical Center, New York, NY, United States
| | - Clara Bertozzi-Villa
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, NewYork-Presbyterian Hospital/Columbia University Irving Medical Center, New York, NY, United States
| | - James Lasky
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, NewYork-Presbyterian Hospital/Columbia University Irving Medical Center, New York, NY, United States
| | - Karin Fuchs
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, NewYork-Presbyterian Hospital/Columbia University Irving Medical Center, New York, NY, United States
| | - Alexander Friedman
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, NewYork-Presbyterian Hospital/Columbia University Irving Medical Center, New York, NY, United States.
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45
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Chakhalian D, Shultz RB, Miles CE, Kohn J. Opportunities for biomaterials to address the challenges of COVID-19. J Biomed Mater Res A 2020; 108:1974-1990. [PMID: 32662571 PMCID: PMC7405498 DOI: 10.1002/jbm.a.37059] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 07/10/2020] [Indexed: 12/19/2022]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has revealed major shortcomings in our ability to mitigate transmission of infectious viral disease and provide treatment to patients, resulting in a public health crisis. Within months of the first reported case in China, the virus has spread worldwide at an unprecedented rate. COVID-19 illustrates that the biomaterials community was engaged in significant research efforts against bacteria and fungi with relatively little effort devoted to viruses. Accordingly, biomaterials scientists and engineers will have to participate in multidisciplinary antiviral research over the coming years. Although tissue engineering and regenerative medicine have historically dominated the field of biomaterials, current research holds promise for providing transformative solutions to viral outbreaks. To facilitate collaboration, it is imperative to establish a mutual language and adequate understanding between clinicians, industry partners, and research scientists. In this article, clinical perspectives are shared to clearly define emerging healthcare needs that can be met by biomaterials solutions. Strategies and opportunities for novel biomaterials intervention spanning diagnostics, treatment strategies, vaccines, and virus-deactivating surface coatings are discussed. Ultimately this review serves as a call for the biomaterials community to become a leading contributor to the prevention and management of the current and future viral outbreaks.
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Affiliation(s)
- Daniel Chakhalian
- Department of Chemistry and Chemical BiologyRutgers – The State University of New JerseyPiscatawayNew JerseyUSA
| | - Robert B. Shultz
- Department of Chemistry and Chemical BiologyRutgers – The State University of New JerseyPiscatawayNew JerseyUSA
- Department of NeurosurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Catherine E. Miles
- Department of Chemistry and Chemical BiologyRutgers – The State University of New JerseyPiscatawayNew JerseyUSA
| | - Joachim Kohn
- Department of Chemistry and Chemical BiologyRutgers – The State University of New JerseyPiscatawayNew JerseyUSA
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Rezaei N, Jafari M, Nazari A, Salehi S, Talati F, Torab R, Nejad-Rahim R. A novel methodology and new concept of SARS-CoV-2 elimination in heating and ventilating air conditioning systems using waste heat recovery. AIP ADVANCES 2020; 10:085308. [PMID: 33194314 PMCID: PMC7665056 DOI: 10.1063/5.0021575] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 07/14/2020] [Indexed: 05/07/2023]
Abstract
Heating and ventilation air conditioning systems in hospitals (cleanroom HVAC systems) are used to control the transmission/spreading of airborne diseases such as COVID-19. Air exiting from these systems may contribute to the spreading of coronavirus droplets outside of hospitals. Some research studies indicate that the shortest time of survival of SARS-CoV-2 in aerosol form (as droplets in the air) is four hours and the virus becomes inactive above 60 °C air temperature. Therefore, SARS-CoV-2 droplets cannot exit from the exhaust duct if the temperature is above 60 °C. At the condenser, heat is dissipated in the form of hot air which could be utilized to warm the exhaust air. The objective of this paper is to establish a novel technique for eliminating SARS-CoV-2 from cleanroom HVAC systems using the recovered heat of exhaust air. This can eliminate SARS-CoV-2 and reduce the greenhouse effect.
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Affiliation(s)
- Naser Rezaei
- University of Tabriz, Department of Mechanical
Engineering, Tabriz, Iran
| | - Moharram Jafari
- University of Tabriz, Department of Mechanical
Engineering, Tabriz, Iran
| | - Ata Nazari
- University of Tabriz, Department of Mechanical
Engineering, Tabriz, Iran
| | - Sina Salehi
- University of Tabriz, Department of Mechanical
Engineering, Tabriz, Iran
| | - Faramarz Talati
- University of Tabriz, Department of Mechanical
Engineering, Tabriz, Iran
| | - Reza Torab
- Tabriz University of Medical Sciences, Department
of Orthopedics, Tabriz, Iran
| | - Rahim Nejad-Rahim
- Urmia University of Medical Sciences, Department
of Dermatology and Infectious Diseases, Urmia,
Iran
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47
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Xu C, Wei X, Liu L, Su L, Liu W, Wang Y, Nielsen PV. Effects of personalized ventilation interventions on airborne infection risk and transmission between occupants. BUILDING AND ENVIRONMENT 2020; 180:107008. [PMID: 32834416 PMCID: PMC7260576 DOI: 10.1016/j.buildenv.2020.107008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/30/2020] [Accepted: 05/23/2020] [Indexed: 05/03/2023]
Abstract
The role of personalized ventilation (PV) in protecting against airborne disease transmission between occupants was evaluated by considering two scenarios with different PV alignments. The possibility that PV may facilitate the transport of exhaled pathogens was explored by performing experiments with droplets and applying PV to a source or/and a target manikin. The risk of direct and indirect exposure to droplets in the inhalation zone of the target was estimated, with these exposure types defined according to their different origins. The infection risk of influenza A, a typical disease transmitted via air, was predicted based on a dose-response model. Results showed that the flow interactions between PV and the infectious exhaled flow would facilitate airborne transmission between occupants in two ways. First, application of PV to the source caused more than 90% of indirect exposure of the target. Second, entrainment of the PV jet directly from the infectious exhalation increased direct exposure of the target by more than 50%. Thus, these scenarios for different PV application modes indicated that continuous exposure to exhaled influenza A virus particles for 2 h would correspond with an infection probability ranging from 0.28 to 0.85. These results imply that PV may protect against infection only when it is maintained with a high ventilation efficiency at the inhalation zone, which can be realized by reduced entrainment of infectious flow and higher clean air volume. Improved PV design methods that could maximize the positive effects of PV on disease control in the human microenvironment are discussed.
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Affiliation(s)
- Chunwen Xu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
| | - Xiongxiong Wei
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
| | - Li Liu
- Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an, 710055, China
- Corresponding author. Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China.
| | - Li Su
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an, 710055, China
| | - Wenbing Liu
- College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
| | - Yi Wang
- State Key Laboratory of Green Building in Western China, Xian University of Architecture & Technology, Xi'an, 710055, China
| | - Peter V. Nielsen
- Department of Civil Engineering, Aalborg University, Aalborg, 9000, Denmark
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48
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Xia T, Yang M, Marabella I, Lee EM, Olson B, Zarling D, Torremorell M, Clack HL. Inactivation of airborne porcine reproductive and respiratory syndrome virus (PRRSv) by a packed bed dielectric barrier discharge non-thermal plasma. JOURNAL OF HAZARDOUS MATERIALS 2020; 393:122266. [PMID: 32126420 DOI: 10.1016/j.jhazmat.2020.122266] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 02/04/2020] [Accepted: 02/08/2020] [Indexed: 05/16/2023]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSv) is one of the most significant airborne viruses impacting the pork industry in the US. Non-thermal plasmas (NTPs) are electrical discharges comprised of reactive radicals and excited species that inactivate viruses and bacteria. Our previous experiments using a packed bed NTP reactor demonstrated effective inactivation of bacteriophage MS2 as a function of applied voltage and power. The present study examined the effectiveness of the same reactor in inactivating aerosolized PRRSv. A PRRSv solution containing ∼105 TCID50/ml of PRRSv VR2332 strain was aerosolized at 3 ml/min by an air-jet nebulizer and introduced into 5 or 12 cfm air flow followed by NTP exposure in the reactor. Twin impingers upstream and downstream of the reactor collected samples of the virus-laden air flow for subsequent TCID50 assay and qPCR analyses. An optical particle sizer measured upstream and downstream aerosol size distributions, giving estimates of aerosol filtration by the reactor. The results showed that PRRSv was inactivated to a similar degree as MS2 at the same conditions, with the maximum 1.3-log inactivation of PRRSv achieved at 20 kV and 12 cfm air flow rate. The results demonstrate the potential of properly optimized NTPs in controlling PRRSv transmission.
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Affiliation(s)
- T Xia
- Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, United States.
| | - M Yang
- Veterinary Population Medicine, University of Minnesota, St. Paul, MN, United States
| | - I Marabella
- Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - E M Lee
- Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL, United States
| | - B Olson
- Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - D Zarling
- Mechanical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - M Torremorell
- Veterinary Population Medicine, University of Minnesota, St. Paul, MN, United States
| | - H L Clack
- Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, United States
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49
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Roberts JD, Tehrani SO. Environments, Behaviors, and Inequalities: Reflecting on the Impacts of the Influenza and Coronavirus Pandemics in the United States. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E4484. [PMID: 32580429 PMCID: PMC7345270 DOI: 10.3390/ijerph17124484] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/12/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022]
Abstract
In the past century, dramatic shifts in demographics, globalization and urbanization have facilitated the rapid spread and transmission of infectious diseases across continents and countries. In a matter of weeks, the 2019 coronavirus pandemic devastated communities worldwide and reinforced the human perception of frailty and mortality. Even though the end of this pandemic story has yet to unfold, there is one parallel that is undeniable when a comparison is drawn between the 2019 coronavirus and the 1918 influenza pandemics. The public health response to disease outbreaks has remained nearly unchanged in the last 101 years. Furthermore, the role of environments and human behaviors on the effect and response to the coronavirus pandemic has brought to light many of the historic and contemporaneous inequalities and injustices that plague the United States. Through a reflection of these pandemic experiences, the American burden of disparity and disproportionality on morbidity, mortality and overall social determinants of health has been examined. Finally, a reimagination of a post-coronavirus existence has also been presented along with a discussion of possible solutions and considerations for moving forward to a new and better normal.
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Affiliation(s)
- Jennifer D. Roberts
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD 20742, USA
| | - Shadi O. Tehrani
- School of Architecture and Environmental Design, Iran University of Science and Technology, Tehran 16846-13114, Iran;
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Analysis of Yearly Effectiveness of a Diaphragm Ground Heat Exchanger Supported by an Ultraviolet Sterilamp. ENERGIES 2020. [DOI: 10.3390/en13112804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ground heat exchangers supplement ventilation systems and provide notable power gains by heating ventilated air during winter and cooling it in summer. Additionally, they prevent recuperator exchangers from freezing. In atmospheric air, there are many types of contaminants and microorganisms that significantly affect the quality of ventilated air. The air that flows through the system of pipes of the heat exchanger may also become contaminated. In order to remove contamination from ventilated air, ultraviolet radiation may be used. This article presents a concept of using a UV-C (ultraviolet with a wavelength of 200–280 nm) lamp in the air duct in front of the air handling unit connected to the ground heat exchanger. The UV-C lamp, apart from clearing the air, may also decrease operational costs thanks to eliminating contamination that forms bacterial jelly on heat exchanger elements.
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