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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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Berlanga FA, Gomez P, Esteban A, Liu L, Nielsen PV. Three dimensional analysis of the exhalation flow in the proximity of the mouth. Heliyon 2024; 10:e26283. [PMID: 38434078 PMCID: PMC10906307 DOI: 10.1016/j.heliyon.2024.e26283] [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: 08/01/2023] [Revised: 02/02/2024] [Accepted: 02/09/2024] [Indexed: 03/05/2024] Open
Abstract
The human exhalation flow is characterized in this work from the three-dimensional velocimetry results obtained by using the stereo particle image velocimetry (SPIV) measurement technique on the flow emitted from a realistic airway model. For this purpose, the transient exhalation flow through the mouth of a person performing two different breaths corresponding to two metabolic rates, standing relaxed (SR) and walking active (WA), is emulated and studied. To reproduce the flow realistically, a detailed three-dimensional model obtained from computed tomography measurements on real subjects is used. To cope with the variability of the experimental data, a subsequent analysis of the results is performed using the TR-PIV (time resolved particle image velocimetry) technique. Exhalation produces a transient jet that becomes a puff when flow emission ends. Three-dimensional vector fields of the jet velocity are obtained in five equally spaced transverse planes up to a distance of Image 1 from the mouth at equally spaced time instants Image 2 which will be referred to as phases (φ), from the beginning to the end of exhalation. The time evolution during exhalation of the jet area of influence, the velocity field and the jet air entrainment have been characterized for each of the jet cross sections. The importance of the use of realistic airway models for the study of this type of flow and the influence of the metabolic rate on its development are also analyzed. The results obtained contribute to the characterization of the human exhalation as a pathway of the transmission of pathogens such as SARS-CoV-2 virus.
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Affiliation(s)
- F A Berlanga
- Dept. de Mecánica, ETSII, Universidad Nacional de Educación a Distancia (UNED), E-28040, Madrid, Spain
| | - P Gomez
- Dept. de Mecánica, ETSII, Universidad Nacional de Educación a Distancia (UNED), E-28040, Madrid, Spain
| | - A Esteban
- Dept. de Mecánica, ETSII, Universidad Nacional de Educación a Distancia (UNED), E-28040, Madrid, Spain
| | - L Liu
- Dept. of Building Science and Technology, School of Architecture, Tsinghua University, Haidian District, Beijing, China
| | - P V Nielsen
- Dept. of the Built Environment, Aalborg Universitet, Thomas Manns Vej 23 9220 Aalborg Øst, Denmark
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Sarkhoshkalat M, Nasab MA, Yari MR, Tabatabaee SS, Ghavami V, Joulaei F, Sarkhosh M. Assessment of UV radiation effects on airborne mucormycetes and bacterial populations in a hospital environment. Sci Rep 2024; 14:2708. [PMID: 38302627 PMCID: PMC10834397 DOI: 10.1038/s41598-024-53100-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 01/27/2024] [Indexed: 02/03/2024] Open
Abstract
Infections, such as mucormycosis, often result from inhaling sporangiospore present in the environment. Surprisingly, the extent of airborne Mucormycetes sporangiospore concentrations remains inadequately explored. This study aimed to assess the influence of UV radiation on microbial populations and Mucormycetes spore levels within a hospital environment in northern Iran. A comprehensive dataset comprising 298 air samples collected from both indoor and outdoor settings was compiled. The culture was conducted using Blood Agar and Dichloran Rose Bengal Chloramphenicol (DRBC) culture media, with Chloramphenicol included for fungal agents and Blood Agar for bacterial. Before UV treatment, the average count of Mucormycetes ranged from 0 to 26.4 ± 25.28 CFU m-3, fungal agents from 2.24 ± 3.22 to 117.24 ± 27.6 CFU m-3, and bacterial agents from 29.03 ± 9.9 to 359.37 ± 68.50 CFU m-3. Following UV irradiation, the averages were as follows: Mucormycetes ranged from 0 to 7.85 ± 6.8 CFU m-3, fungal agents from 16.58 ± 4.79 to 154.98 ± 28.35 CFU m-3, and bacterial agents from 0.38 ± 0.65 to 43.92 ± 6.50 CFU m-3. This study, notably marks the pioneering use of UV light to mitigate Mucormycetes spore counts and bacterial agents in northeastern Iran, contributing to the advancement of environmental health and safety practices in hospital settings.
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Affiliation(s)
| | - Mahdi Ahmadi Nasab
- Student Research Committee, Department of Environmental Health Engineering, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Reza Yari
- Student Research Committee, Department of Environmental Health Engineering, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Saeed Tabatabaee
- Social Determinants of Health Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
- Department of Management Sciences and Health Economics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Vahid Ghavami
- Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Fatemeh Joulaei
- Department of Environmental Health Engineering, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Sarkhosh
- Department of Environmental Health Engineering, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran.
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Abramova AV, Kozlov DA, Veselova VO, Kozlova TO, Ivanova OS, Mikhalev ES, Voytov YI, Baranchikov AE, Ivanov VK, Cravotto G. Coating of Filter Materials with CeO 2 Nanoparticles Using a Combination of Aerodynamic Spraying and Suction. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:3168. [PMID: 38133066 PMCID: PMC10745644 DOI: 10.3390/nano13243168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/08/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Textiles and nonwovens (including those used in ventilation systems as filters) are currently one of the main sources of patient cross-infection. Healthcare-associated infections (HAIs) affect 5-10% of patients and stand as the tenth leading cause of death. Therefore, the development of new methods for creating functional nanostructured coatings with antibacterial and antiviral properties on the surfaces of textiles and nonwoven materials is crucial for modern medicine. Antimicrobial filter technology must be high-speed, low-energy and safe if its commercialization and mass adoption are to be successful. Cerium oxide nanoparticles can act as active components in these coatings due to their high antibacterial activity and low toxicity. This paper focuses on the elaboration of a high-throughput and resource-saving method for the deposition of cerium oxide nanoparticles onto nonwoven fibrous material for use in air-conditioning filters. The proposed spraying technique is based on the use of an aerodynamic emitter and simultaneous suction. Cerium oxide nanoparticles have successfully been deposited onto the filter materials used in air conditioning systems; the antibacterial activity of the ceria-modified filters exceeded 4.0.
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Affiliation(s)
- Anna V. Abramova
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Daniil A. Kozlov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Varvara O. Veselova
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Taisiya O. Kozlova
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Olga S. Ivanova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia;
| | - Egor S. Mikhalev
- Limited Liability Company “Angstrem”, Bolshaya Polyanka, 51A/9, 119180 Moscow, Russia;
| | - Yuri I. Voytov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Alexandr E. Baranchikov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Vladimir K. Ivanov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 31, 119991 Moscow, Russia; (D.A.K.); (V.O.V.); (T.O.K.); (Y.I.V.); (V.K.I.)
| | - Giancarlo Cravotto
- Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, Via P. Giuria 9, 10125 Turin, Italy
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Voidarou C, Rozos G, Stavropoulou E, Giorgi E, Stefanis C, Vakadaris G, Vaou N, Tsigalou C, Kourkoutas Y, Bezirtzoglou E. COVID-19 on the spectrum: a scoping review of hygienic standards. Front Public Health 2023; 11:1202216. [PMID: 38026326 PMCID: PMC10646607 DOI: 10.3389/fpubh.2023.1202216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
The emergence of COVID-19 in Wuhan, China, rapidly escalated into a worldwide public health crisis. Despite numerous clinical treatment endeavors, initial defenses against the virus primarily relied on hygiene practices like mask-wearing, meticulous hand hygiene (using soap or antiseptic solutions), and maintaining social distancing. Even with the subsequent advent of vaccines and the commencement of mass vaccination campaigns, these hygiene measures persistently remain in effect, aiming to curb virus transmission until the achievement of herd immunity. In this scoping review, we delve into the effectiveness of these measures and the diverse transmission pathways, focusing on the intricate interplay within the food network. Furthermore, we explore the virus's pathophysiology, considering its survival on droplets of varying sizes, each endowed with distinct aerodynamic attributes that influence disease dispersion dynamics. While respiratory transmission remains the predominant route, the potential for oral-fecal transmission should not be disregarded, given the protracted presence of viral RNA in patients' feces after the infection period. Addressing concerns about food as a potential viral vector, uncertainties shroud the virus's survivability and potential to contaminate consumers indirectly. Hence, a meticulous and comprehensive hygienic strategy remains paramount in our collective efforts to combat this pandemic.
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Affiliation(s)
| | - Georgios Rozos
- Veterinary Directorate, South Aegean Region, Ermoupolis, Greece
| | - Elisavet Stavropoulou
- Department of Medicine, Lausanne University Hospital (CHUV), University of Lausanne, Lausanne, Switzerland
| | - Elpida Giorgi
- Laboratory of Hygiene and Environmental Protection, Department of Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Christos Stefanis
- Laboratory of Hygiene and Environmental Protection, Department of Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Georgios Vakadaris
- Laboratory of Hygiene and Environmental Protection, Department of Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Natalia Vaou
- Laboratory of Hygiene and Environmental Protection, Department of Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Christina Tsigalou
- Laboratory of Hygiene and Environmental Protection, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Yiannis Kourkoutas
- Laboratory of Applied Microbiology and Biotechnology, Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Eugenia Bezirtzoglou
- Laboratory of Hygiene and Environmental Protection, Department of Medicine, Democritus University of Thrace, Alexandroupolis, Greece
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Sabuco-Tébar EA, Arense-Gonzalo JJ, Campayo-Rojas FJ. Relationship Between Airborne Fungi Presence and the Position of the High Efficiency Particulate Air Filter in the Heating, Ventilation, and Air Conditioning System. HERD-HEALTH ENVIRONMENTS RESEARCH & DESIGN JOURNAL 2023; 16:56-68. [PMID: 37365804 DOI: 10.1177/19375867231181556] [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] [Indexed: 06/28/2023]
Abstract
AIM Establish the influence of the terminal or nonterminal position of High Efficiency Particulate Air (HEPA) filters in the Heating, Ventilation, and Air Conditioning (HVAC) system on the presence of airborne fungi in controlled environment rooms. BACKGROUND Fungal infections are an important cause of morbidity and mortality in hospitalized patients. METHODS This study was realized from 2010 to 2017, in rooms with terminal and nonterminal HEPA filters, in eight Spanish hospitals. In rooms with terminal HEPA filters, 2,053 and 2,049 samples were recollected, and in rooms with nonterminal HEPA filters, 430 and 428 samples were recollected in the air discharge outlet (Point 1) and in the center of the room (Point 2), respectively. Temperature, relative humidity, air changes per hour, and differential pressure were recollected. RESULTS Multivariable analysis showed higher odds ratio (OR) of airborne fungi presence when HEPA filters were in nonterminal position (OR: 6.78; 95% CI [3.77, 12.20]) in Point 1 and (OR: 4.43; 95% CI [2.65, 7.40]) in Point 2. Other parameters influenced airborne fungi presence, such as temperature (OR: 1.23; 95% CI [1.06, 1.41]) in Point 2 differential pressure (OR: 0.86; 95% CI [0.84, 0.90]) and (OR: 0.88; 95% CI [0.86, 0.91]) in Points 1 and 2, respectively. CONCLUSIONS HEPA filter in terminal position of the HVAC system reduces the presence of airborne fungi. To decrease the presence of airborne fungi, adequate maintenance of the environmental and design parameters is necessary in addition to the terminal position of the HEPA filter.
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Affiliation(s)
- Emiliana A Sabuco-Tébar
- Department of Preventive Medicine, "Reina Sofia" University Clinical Hospital, Murcia, Spain
| | - Julián J Arense-Gonzalo
- Division of Preventive Medicine and Public Health, Department of Public Health Sciences, University of Murcia School of Medicine, Spain
| | - F Javier Campayo-Rojas
- Department of Preventive Medicine, "Reina Sofia" University Clinical Hospital, Murcia, Spain
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Talukdar R, Sahu SK, Rajaram M. Implementation Status of Airborne Infection Control Measures in Primary and Secondary Public Health Facilities, Puducherry: A Mixed-Methods Study. Indian J Community Med 2023; 48:483-491. [PMID: 37469915 PMCID: PMC10353669 DOI: 10.4103/ijcm.ijcm_196_22] [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: 02/26/2022] [Accepted: 04/19/2023] [Indexed: 07/21/2023] Open
Abstract
Background Poor ventilation in healthcare settings is a concern for airborne infections, particularly in light of the potential for coronavirus disease 2019 (COVID-19) transmission. This study aimed to assess the implementation status of airborne infection control (AIC) measures in primary and secondary public healthcare facilities (HCFs) and to explore the facilitating factors and barriers in the implementation of AIC measures. Methods A mixed-methods approach was adopted, which includes a cross-sectional descriptive study using a checklist to collect data on the implementation of AIC measures in 22 primary and two secondary public HCFs in Puducherry, South India, between October 2020 and February 2021. Further, key informant interviews (KIIs) were conducted among medical officers (MOs). The qualitative data were manually analyzed, and transcripts created from handwritten notes and audio recordings were deductively evaluated. Results Of the twenty-four health facilities visited, 54.2% had infection control (IC) committees. Annual IC training was held for housekeeping staff, MOs, nurses, and laboratory technicians in 23 (95.8%), 21 (87.5%), 20 (83.4%), and 14 (58.4%) facilities, respectively. Respiratory symptomatic patients were counseled on cough etiquettes in 22 (91.6%) facilities. Adequate cross-ventilation was present in outpatient departments in 16 (66.6%) institutions. N95 masks and face shields were provided in 21 (87.5%) facilities. Training through the KAYAKALP program and the presence of a separate sputum collection area were facilitators of IC, while lack of patient adherence and delays in fund release were found as barriers. Conclusion Overall, the AIC measures were well-implemented, but improvements are needed in infrastructure development for patient segregation in outpatient departments and dedicated AIC training for all healthcare personnel.
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Affiliation(s)
- Rounik Talukdar
- Department of Preventive and Social Medicine, JIPMER, Puducherry, India
| | | | - Manju Rajaram
- Department of Pulmonary Medicine, JIPMER, Puducherry, India
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Oswin HP, Haddrell AE, Hughes C, Otero-Fernandez M, Thomas RJ, Reid JP. Oxidative Stress Contributes to Bacterial Airborne Loss of Viability. Microbiol Spectr 2023; 11:e0334722. [PMID: 36912675 PMCID: PMC10101003 DOI: 10.1128/spectrum.03347-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 01/18/2023] [Indexed: 03/14/2023] Open
Abstract
While the airborne decay of bacterial viability has been observed for decades, an understanding of the mechanisms driving the decay has remained elusive. The airborne transport of bacteria is often a key step in their life cycle and as such, characterizing the mechanisms driving the airborne decay of bacteria is an essential step toward a more complete understanding of microbial ecology. Using the Controlled Electrodynamic Levitation and Extraction of Bioaerosols onto a Substrate (CELEBS), it was possible to systematically evaluate the impact of different physicochemical and environmental parameters on the survival of Escherichia coli in airborne droplets of Luria Bertani broth. Rather than osmotic stress driving the viability loss, as was initially considered, oxidative stress was found to play a key role. As the droplets evaporate and equilibrate with the surrounding environment, the surface-to-volume ratio increases, which in turn increased the formation of reactive oxygen species in the droplet. These reactive oxygen species appear to play a key role in driving the airborne loss of viability of E. coli. IMPORTANCE The airborne transport of bacteria has a wide range of impacts, from disease transmission to cloud formation. By understanding the factors that influence the airborne stability of bacteria, we can better understand these processes. However, while we have known for several decades that airborne bacteria undergo a gradual loss of viability, we have not previously identified the mechanisms driving this process. In this work, we discovered that oxygen surrounding an airborne droplet facilitates the formation of reactive oxygen species within the droplet, which then gradually damage and kill bacteria within the droplet. This discovery indicates that adaptations to help bacteria deal with oxidative stress may also aid their airborne survival and be essential adaptations for bacterial airborne pathogens. Understanding the adaptations bacteria need to survive in airborne droplets could eventually lead to the development of novel antimicrobials designed to inhibit their airborne survival, helping to prevent the transmission of disease.
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Affiliation(s)
- Henry P. Oswin
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
| | - Allen E. Haddrell
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
| | - Cordelia Hughes
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
| | - Mara Otero-Fernandez
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
| | - Richard J. Thomas
- Defence Science Technology Laboratory (DSTL), Porton Down, Salisbury, United Kingdom
| | - Jonathan P. Reid
- School of Chemistry, Cantock’s Close, University of Bristol, Bristol, United Kingdom
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Muacevic A, Adler JR, Jalily QA, Dinesh Eshwar M, Dodda S. Assessment of the Occupational Risk of Tuberculosis & Air Borne Infection Control in High-Risk Hospital Wards and Its Implications on Healthcare Workers in a Tertiary Care Hospital in South India. Cureus 2023; 15:e33785. [PMID: 36819336 PMCID: PMC9931371 DOI: 10.7759/cureus.33785] [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] [Accepted: 01/14/2023] [Indexed: 01/16/2023] Open
Abstract
Introduction The indoor air in hospitals could play a significant role in the transmission of a wide array of infections, especially in respiratory intensive care units, pulmonary outpatient departments, and other areas. Unprotected coughing and sneezing may facilitate the release of aerosols and contaminate the indoor environment. The majority of infections transmitted through these modes include viral diseases, including tuberculosis (TB), influenza, and measles, among several others. Moreover, the possibility of direct and indirect transmission of microbes by air has been underestimated in hospital settings, especially in developing countries. This study therefore was carried out to assess the burden of microbes in the air of selected wards in a tertiary care hospital and evaluate the occupational risk of some infections among healthcare workers (HCWs). Methods This study was carried out between September 2019 and February 2021 at a tertiary care teaching hospital in South India. A total of 30 symptomatic healthcare workers (HCWs) were included in the study and were screened for present and past tuberculosis (TB) as well as other lower respiratory tract infections. A tuberculin skin test, chest X-ray, and sputum acid-fast staining were performed on all the HCWs who were negative for other bacterial infections and were symptomatic. The study was conducted in coordination with the pulmonology department. Active monitoring of air was performed by microbiological air sampler in the respiratory intensive care unit (RICU) and other high-risk areas including the pulmonology outpatient department (OPD), the radiology OPD, and the microbiology department. Results Sputum for tuberculous bacteria was positive in four (16.6%) HCWs. The chest X-ray showed radiological findings suggestive of TB in five (20.8%) HCWs. Three (12.5%) HCWs who were screened for extrapulmonary TB revealed one (33.3%) was positive for TB of the hip joint. Among the HCWs, eight (33%) returned positive tuberculin tests. Assessment of the hospital air in the RICU revealed the bacterial count (288 CFU/m3) exceeded the normal limit (≤50 CFU/m3). The COVID-19 isolation ward showed the lowest bacterial count (06 CFU/m3) and no fungi. The predominant bacterial isolates were gram-positive cocci in clusters (Methicillin-sensitive Staphylococcus aureus). After proper disinfection and correction of ventilation techniques, the resampling results noted microbial colonies under normal limits. Conclusion A high burden of TB was noted among the HCWs. The airborne infection control strategies are essential to minimize the risk of nosocomial infections and occupational TB risk to HCWs. Most microbes are transmitted through the airborne route and therefore it is extremely important to take measures to control the transmission of such pathogens in hospital settings.
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Long T, Ye Z, Tang Y, Shi J, Wen J, Chen C, Huo Q. Comparison of bacterial community structure in PM 2.5 during hazy and non-hazy periods in Guilin, South China. AEROBIOLOGIA 2023; 39:87-103. [PMID: 36568442 PMCID: PMC9762634 DOI: 10.1007/s10453-022-09777-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 12/09/2022] [Indexed: 05/19/2023]
Abstract
UNLABELLED In recent years, significant efforts have been made to study changes in the levels of air pollutants at regional and urban scales, and changes in bioaerosols during air pollution events have attracted increasing attention. In this study, the bacterial structure of PM2.5 was analysed under different environmental conditions during hazy and non-hazy periods in Guilin. A total of 32 PM2.5 samples were collected in December 2020 and July 2021, and the microbial community structures were analysed using high-throughput sequencing methods. The results show that air pollution and climate change alter the species distribution and community diversity of bacteria in PM2.5, particularly Sphingomonas and Pseudomonas. The structure of the bacterial community composition is related to diurnal variation, vertical height, and urban area and their interactions with various environmental factors. This is a comprehensive study that characterises the variability of bacteria associated with PM2.5 in a variety of environments, highlighting the impacts of environmental effects on the atmospheric microbial community. The results will contribute to our understanding of haze trends in China, particularly the relationship between bioaerosol communities and the urban environment. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10453-022-09777-0.
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Affiliation(s)
- Tengfa Long
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, 541006 China
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
| | - Ziwei Ye
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, 541006 China
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
| | - Yanchun Tang
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, 541006 China
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
| | - Jiaxin Shi
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, 541006 China
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
| | - Jianhui Wen
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
- Guilin Ecological Environmental Monitoring Center, Guilin, 541004 China
| | - Chunqiang Chen
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, 541006 China
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
| | - Qiang Huo
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, 541006 China
- College of Environment and Resources, Guangxi Normal University, Guilin, 541006 China
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Pan Y, Zhang H, Niu Z, An Y, Chen C. Boundary conditions for exhaled airflow from a cough with a surgical or N95 mask. INDOOR AIR 2022; 32:e13088. [PMID: 36040272 PMCID: PMC9538929 DOI: 10.1111/ina.13088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 06/10/2022] [Accepted: 07/16/2022] [Indexed: 05/12/2023]
Abstract
Wearing surgical or N95 masks is effective in reducing the infection risks of airborne infectious diseases. However, in the literature there are no detailed boundary conditions for airflow from a cough when a surgical or N95 mask is worn. These boundary conditions are essential for accurate prediction of exhaled particle dispersion by computational fluid dynamics (CFD). This study first constructed a coughing manikin with an exhalation system to simulate a cough from a person. The smoke visualization method was used to measure the airflow profile from a cough. To validate the setup of the coughing manikin, the results were compared with measured data from subject tests reported in the literature. The validated coughing manikin was then used to measure the airflow boundary conditions for a cough when a surgical mask was worn and when an N95 mask was worn, respectively. Finally, this study applied the developed airflow boundary conditions to calculate person-to-person particle transport from a cough when masks are worn. The calculated exhaled particle patterns agreed well with the smoke pattern in the visualization experiments. Furthermore, the calculated results indicated that, when the index person wore a surgical and a N95 mask, the total exposure of the receptor was reduced by 93.0% and 98.8%, respectively.
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Affiliation(s)
- Yue Pan
- Department of Mechanical and Automation EngineeringThe Chinese University of Hong KongHong Kong SARChina
| | - Haiqiang Zhang
- Department of Mechanical and Automation EngineeringThe Chinese University of Hong KongHong Kong SARChina
| | - Zhuolun Niu
- Department of Mechanical and Automation EngineeringThe Chinese University of Hong KongHong Kong SARChina
| | - Yuting An
- Department of Mechanical and Automation EngineeringThe Chinese University of Hong KongHong Kong SARChina
| | - Chun Chen
- Department of Mechanical and Automation EngineeringThe Chinese University of Hong KongHong Kong SARChina
- Shenzhen Research InstituteThe Chinese University of Hong KongShenzhenChina
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12
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Antibacterial Activity of Electrospun Polyacrylonitrile Copper Nanoparticle Nanofibers on Antibiotic Resistant Pathogens and Methicillin Resistant Staphylococcus aureus (MRSA). NANOMATERIALS 2022; 12:nano12132139. [PMID: 35807975 PMCID: PMC9268565 DOI: 10.3390/nano12132139] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/14/2022] [Accepted: 06/18/2022] [Indexed: 12/03/2022]
Abstract
Bacteria induced diseases such as community-acquired pneumonia (CAP) are easily transmitted through respiratory droplets expelled from a person’s nose or mouth. It has become increasingly important for researchers to discover materials that can be implemented in in vitro surface contact settings which disrupt bacterial growth and transmission. Copper (Cu) is known to have antibacterial properties and have been used in medical applications. This study investigates the antibacterial properties of polyacrylonitrile (PAN) based nanofibers coated with different concentrations of copper nanoparticles (CuNPs). Different concentrations of copper sulfate (CuSO4) and polyacrylonitrile (PAN) were mixed with dimethylformamide (DMF) solution, an electrospinning solvent that also acts as a reducing agent for CuSO4, which forms CuNPs and Cu ions. The resulting colloidal solutions were electrospun into nanofibers, which were then characterized using various analysis techniques. Methicillin-Resistant isolates of Staphylococcus aureus, an infective strain that induces pneumonia, were incubated with cutouts of various nanocomposites using disk diffusion methods on Luria-Bertani (LB) agar to test for the polymers’ antibacterial properties. Herein, we disclose that PAN-CuNP nanofibers have successfully demonstrated antibacterial activity against bacteria that were otherwise resistant to highly effective antibiotics. Our findings reveal that PAN-CuNP nanofibers have the potential to be used on contact surfaces that are at risk of contracting bacterial infections, such as masks, in vivo implants, or surgical intubation.
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13
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Ribaric NL, Vincent C, Jonitz G, Hellinger A, Ribaric G. Hidden hazards of SARS-CoV-2 transmission in hospitals: A systematic review. INDOOR AIR 2022; 32:e12968. [PMID: 34862811 DOI: 10.1111/ina.12968] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 09/17/2021] [Accepted: 11/19/2021] [Indexed: 05/04/2023]
Abstract
Despite their considerable prevalence, dynamics of hospital-associated COVID-19 are still not well understood. We assessed the nature and extent of air- and surface-borne SARS-CoV-2 contamination in hospitals to identify hazards of viral dispersal and enable more precise targeting of infection prevention and control. PubMed, ScienceDirect, Web of Science, Medrxiv, and Biorxiv were searched for relevant articles until June 1, 2021. In total, 51 observational cross-sectional studies comprising 6258 samples were included. SARS-CoV-2 RNA was detected in one in six air and surface samples throughout the hospital and up to 7.62 m away from the nearest patients. The highest detection rates and viral concentrations were reported from patient areas. The most frequently and heavily contaminated types of surfaces comprised air outlets and hospital floors. Viable virus was recovered from the air and fomites. Among size-fractionated air samples, only fine aerosols contained viable virus. Aerosol-generating procedures significantly increased (ORair = 2.56 (1.46-4.51); ORsurface = 1.95 (1.27-2.99)), whereas patient masking significantly decreased air- and surface-borne SARS-CoV-2 contamination (ORair = 0.41 (0.25-0.70); ORsurface = 0.45 (0.34-0.61)). The nature and extent of hospital contamination indicate that SARS-CoV-2 is likely dispersed conjointly through several transmission routes, including short- and long-range aerosol, droplet, and fomite transmission.
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Affiliation(s)
- Noach Leon Ribaric
- Faculty of Medicine, University Medical Center Hamburg-Eppendorf, University of Hamburg, Hamburg, Germany
| | - Charles Vincent
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Günther Jonitz
- German Medical Association, Berlin, Germany
- State Chamber of Physicians Berlin, Berlin, Germany
| | - Achim Hellinger
- Department of General, Visceral, Endocrine and Oncologic Surgery, Fulda Hospital, University Medicine Marburg Campus Fulda, Fulda, Germany
| | - Goran Ribaric
- Johnson & Johnson Institute, Norderstedt, Germany
- MedTech Europe, Antimicrobial Resistance (AMR) and Healthcare Associated Infections (HAI) Sector Group, Brussels, Belgium
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14
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Nunayon SS, Zhang HH, Chan V, Kong RYC, Lai ACK. Study of synergistic disinfection by UVC and positive/negative air ions for aerosolized Escherichia coli, Salmonella typhimurium, and Staphylococcus epidermidis in ventilation duct flow. INDOOR AIR 2022; 32:e12957. [PMID: 34796996 DOI: 10.1111/ina.12957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 10/29/2021] [Accepted: 10/30/2021] [Indexed: 06/13/2023]
Abstract
The efficacy of the in-duct application of ultraviolet waveband C (UVC) emitting at 254 nm wavelength and air ions against aerosolized bacteria was studied in a full-scale 9-m long ventilation duct. Combined positive and negative ion polarities (bipolar ions) and combined UVC and ions were tested. The UVC was generated by a mercury-type UVC lamp and air ions were generated by positive and negative polarity ionizers. Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), and Staphylococcus epidermidis (S. epidermidis)were tested at a concentration of 108 to 109 cells in 50 ml of sterilized distilled water. The case in which the positive ionizer was placed first, followed by the negative ionizer, demonstrated significantly higher disinfection efficiencies for E. coli (p = 0.007) and S. typhimurium (p < 0.001), but lower efficiency for S. epidermidis (p = 0.01) than the reversed sequence. The combination of UVC (3.71 J/m2 ) and air ions (1.13 × 1012 ions/m3 for positive ions and 8.00 × 1011 ions/m3 for negative ions) led to higher inactivation than individual disinfection agents operating under the same dose. A synergetic inactivation effect was observed for S. epidermidis under the combined UVC and positive ion case, while the combined UVC and negative ion case showed significant synergy effects for E. coli and S. typhimurium.
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Affiliation(s)
- Sunday S Nunayon
- Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China
| | - Hui H Zhang
- Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China
| | - Vincent Chan
- Department of Biomedical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
| | - Richard Y C Kong
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Alvin C K Lai
- Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China
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15
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Niazi S, Groth R, Spann K, Johnson GR. The role of respiratory droplet physicochemistry in limiting and promoting the airborne transmission of human coronaviruses: A critical review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:115767. [PMID: 33243541 PMCID: PMC7645283 DOI: 10.1016/j.envpol.2020.115767] [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: 08/13/2020] [Revised: 09/16/2020] [Accepted: 09/29/2020] [Indexed: 05/19/2023]
Abstract
Whether virulent human pathogenic coronaviruses (SARS-CoV, MERS-CoV, SARS-CoV-2) are effectively transmitted by aerosols remains contentious. Transmission modes of the novel coronavirus have become a hot topic of research with the importance of airborne transmission controversial due to the many factors that can influence virus transmission. Airborne transmission is an accepted potential route for the spread of some viral infections (measles, chickenpox); however, aerosol features and infectious inoculum vary from one respiratory virus to another. Infectious virus-laden aerosols can be produced by natural human respiratory activities, and their features are vital determinants for virus carriage and transmission. Physicochemical characteristics of infectious respiratory aerosols can influence the efficiency of virus transmission by droplets. This critical review identifies studies reporting instances of infected patients producing airborne human pathogenic coronaviruses, and evidence for the role of physical/chemical characteristics of human-generated droplets in altering embedded viruses' viability. We also review studies evaluating these viruses in the air, field studies and available evidence about seasonality patterns. Ultimately the literature suggests that a proportion of virulent human coronaviruses can plausibly be transmitted via the air, even though this might vary in different conditions. Evidence exists for respirable-sized airborne droplet nuclei containing viral RNA, although this does not necessarily imply that the virus is transmittable, capable of replicating in a recipient host, or that inoculum is sufficient to initiate infection. However, evidence suggests that coronaviruses can survive in simulated droplet nuclei for a significant time (>24 h). Nevertheless, laboratory nebulized virus-laden aerosols might not accurately model the complexity of human carrier aerosols in studying airborne viral transport. In summary, there is disagreement on whether wild coronaviruses can be transmitted via an airborne path and display seasonal patterns. Further studies are therefore required to provide supporting evidence for the role of airborne transmission and assumed mechanisms underlying seasonality.
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Affiliation(s)
- Sadegh Niazi
- Queensland University of Technology (QUT), Science and Engineering Faculty, School of Earth and Atmospheric Sciences, Brisbane, Australia
| | - Robert Groth
- Queensland University of Technology (QUT), Science and Engineering Faculty, School of Earth and Atmospheric Sciences, Brisbane, Australia
| | - Kirsten Spann
- Queensland University of Technology, Faculty of Health, School of Biomedical Sciences, Brisbane, Australia
| | - Graham R Johnson
- Queensland University of Technology (QUT), Science and Engineering Faculty, School of Earth and Atmospheric Sciences, Brisbane, Australia.
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16
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Hammond A, Khalid T, Thornton HV, Woodall CA, Hay AD. Should homes and workplaces purchase portable air filters to reduce the transmission of SARS-CoV-2 and other respiratory infections? A systematic review. PLoS One 2021; 16:e0251049. [PMID: 33914823 PMCID: PMC8084223 DOI: 10.1371/journal.pone.0251049] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 04/20/2021] [Indexed: 12/11/2022] Open
Abstract
Respiratory infections, including SARS-CoV-2, are spread via inhalation or ingestion of airborne pathogens. Airborne transmission is difficult to control, particularly indoors. Manufacturers of high efficiency particulate air (HEPA) filters claim they remove almost all small particles including airborne bacteria and viruses. This study investigates whether modern portable, commercially available air filters reduce the incidence of respiratory infections and/or remove bacteria and viruses from indoor air. We systematically searched Medline, Embase and Cochrane for studies published between January 2000 and September 2020. Studies were eligible for inclusion if they included a portable, commercially available air filter in any indoor setting including care homes, schools or healthcare settings, investigating either associations with incidence of respiratory infections or removal and/or capture of aerosolised bacteria and viruses from the air within the filters. Dual data screening and extraction with narrative synthesis. No studies were found investigating the effects of air filters on the incidence of respiratory infections. Two studies investigated bacterial capture within filters and bacterial load in indoor air. One reported higher numbers of viable bacteria in the HEPA filter than in floor dust samples. The other reported HEPA filtration combined with ultraviolet light reduced bacterial load in the air by 41% (sampling time not reported). Neither paper investigated effects on viruses. There is an important absence of evidence regarding the effectiveness of a potentially cost-efficient intervention for indoor transmission of respiratory infections, including SARS-CoV-2. Two studies provide ‘proof of principle’ that air filters can capture airborne bacteria in an indoor setting. Randomised controlled trials are urgently needed to investigate effects of portable HEPA filters on incidence of respiratory infections.
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Affiliation(s)
- Ashley Hammond
- Centre for Academic Primary Care, NIHR School for Primary Care Research, Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail:
| | - Tanzeela Khalid
- Centre for Academic Primary Care, NIHR School for Primary Care Research, Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Hannah V. Thornton
- Centre for Academic Primary Care, NIHR School for Primary Care Research, Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Claire A. Woodall
- Centre for Academic Primary Care, NIHR School for Primary Care Research, Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Alastair D. Hay
- Centre for Academic Primary Care, NIHR School for Primary Care Research, Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, United Kingdom
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17
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Dillon CF, Dillon MB. Multi-Scale Airborne Infectious Disease Transmission. Appl Environ Microbiol 2021; 87:AEM.02314-20. [PMID: 33277266 PMCID: PMC7851691 DOI: 10.1128/aem.02314-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Airborne disease transmission is central to many scientific disciplines including agriculture, veterinary biosafety, medicine, and public health. Legal and regulatory standards are in place to prevent agricultural, nosocomial, and community airborne disease transmission. However, the overall importance of the airborne pathway is underappreciated, e.g.,, US National Library of Medicine's Medical Subjects Headings (MESH) thesaurus lacks an airborne disease transmission indexing term. This has practical consequences as airborne precautions to control epidemic disease spread may not be taken when airborne transmission is important, but unrecognized. Publishing clearer practical methodological guidelines for surveillance studies and disease outbreak evaluations could help address this situation.To inform future work, this paper highlights selected, well-established airborne transmission events - largely cases replicated in multiple, independently conducted scientific studies. Methodologies include field experiments, modeling, epidemiology studies, disease outbreak investigations and mitigation studies. Collectively, this literature demonstrates that airborne viruses, bacteria, and fungal pathogens have the capability to cause disease in plants, animals, and humans over multiple distances - from near range (< 5 m) to continental (> 500 km) in scale. The plausibility and implications of undetected airborne disease transmission are discussed, including the notable underreporting of disease burden for several airborne transmitted diseases.
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Affiliation(s)
| | - Michael B Dillon
- Atmospheric, Earth, and Energy Division, Lawrence Livermore National Laboratory Livermore, California, USA 94551
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18
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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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19
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Yang XD, Li HL, Cao YE. Influence of Meteorological Factors on the COVID-19 Transmission with Season and Geographic Location. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:E484. [PMID: 33435301 PMCID: PMC7827058 DOI: 10.3390/ijerph18020484] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 12/23/2022]
Abstract
The purpose of this study is to investigate whether the relationship between meteorological factors (i.e., daily maximum temperature, minimum temperature, average temperature, temperature range, relative humidity, average wind speed and total precipitation) and COVID-19 transmission is affected by season and geographical location during the period of community-based pandemic prevention and control. COVID-19 infected case records and meteorological data in four cities (Wuhan, Beijing, Urumqi and Dalian) in China were collected. Then, the best-fitting model of COVID-19 infected cases was selected from four statistic models (Gaussian, logistic, lognormal distribution and allometric models), and the relationship between meteorological factors and COVID-19 infected cases was analyzed using multiple stepwise regression and Pearson correlation. The results showed that the lognormal distribution model was well adapted to describing the change of COVID-19 infected cases compared with other models (R2 > 0.78; p-values < 0.001). Under the condition of implementing community-based pandemic prevention and control, relationship between COVID-19 infected cases and meteorological factors differed among the four cities. Temperature and relative humidity were mainly the driving factors on COVID-19 transmission, but their relations obviously varied with season and geographical location. In summer, the increase in relative humidity and the decrease in maximum temperature facilitate COVID-19 transmission in arid inland cities, while at this point the decrease in relative humidity is good for the spread of COVID-19 in coastal cities. For the humid cities, the reduction of relative humidity and the lowest temperature in the winter promote COVID-19 transmission.
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Affiliation(s)
- Xiao-Dong Yang
- Department of Geography and Spatial Information Techniques/Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, China; (X.-D.Y.); (H.-L.L.)
- Ningbo Universities Collaborative Innovation Center for Land and Marine Spatial Utilization and Governance Research at Ningbo University, Ningbo 315211, China
| | - Hong-Li Li
- Department of Geography and Spatial Information Techniques/Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, China; (X.-D.Y.); (H.-L.L.)
- Institute of East China Sea, Ningbo University, Ningbo 315211, China
| | - Yue-E Cao
- School of Environmental and Geographical Science, Shanghai Normal University, Shanghai 200234, China
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20
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Zhao Y, Zhang J, Wang S, Yu L, Yu H, Wang Y, Feng L. Efficacy of 75% alcohol in pretreatment of the Andersen sampler in trapping maximum airborne microbes. AEROBIOLOGIA 2021; 37:171-178. [PMID: 33424104 PMCID: PMC7781652 DOI: 10.1007/s10453-020-09668-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
The present study was conducted to evaluate the effects of the pretreatment methods and sampling time on the sampling of airborne bacteria in hospitals. Methods for the pretreatment of Andersen samplers, namely, non-sterilized, 75% ethanol and autoclaving sampled for 5 min, 10 min and 15 min in the general ward and class 1000 clean operating department, respectively, were studied. Statistical analysis was used to compare the differences in sampling results of airborne bacteria under different pretreatment methods, sampling time and environmental conditions. In the first test, the sampling results of the airborne bacteria obtained by pretreatment of the sampler with 75% ethanol and without pre-treatment were not very different, and the sampling results showed a certain declining trend with the extension of the sampling time. In the second test, the pretreatment effect of autoclaving was significantly better than that of 75% ethanol, and the sampling time had no effect on the sampling results. After removing the influencing factors of the environment, the results were consistent with the results of the second test. It was observed that the Andersen samplers should not be pretreated with 75% ethanol before airborne microbes sampling. The pretreatment should be carried out by autoclaving, and the sampling time has little effect on the sampling results.
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Affiliation(s)
- Yan Zhao
- Department of Environment and Health, Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District, Tianjin, China
| | - Jingwei Zhang
- Department of Environment and Health, Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District, Tianjin, China
| | - Shumei Wang
- Department of Pathogen Microbiology, Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Lingqi Yu
- Department of Pathogen Microbiology, Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Hao Yu
- Department of Environment and Health, Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District, Tianjin, China
| | - Yuwen Wang
- Department of Environment and Health, Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District, Tianjin, China
| | - Lihong Feng
- Department of Environment and Health, Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District, Tianjin, China
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21
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Daubert G, Gillet G, Guet L, Marini H, Merle V. General Practitioners' Practice premises and Risk of Viral Cross-Transmission: A French Observational Multicenter Study. J Prim Care Community Health 2021; 12:21501327211043734. [PMID: 34486437 PMCID: PMC8424613 DOI: 10.1177/21501327211043734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The common areas of general practitioners' practices (eg, reception, secretariat, waiting room, toilets) are places at risk of cross-transmission of viral diseases such as COVID-19, however risk is poorly documented. AIM To evaluate the risks of viral cross-transmission in general practitioners' practices based on the organization of the common areas of the premises. DESIGN AND SETTING Cross-sectional multicenter observational study in randomly selected general practitioners' practices in a French department (Seine-Maritime). The practices were included in 4 strata (1, 2, 3-5, or ≥6 general practitioners). METHOD Each practice was visited and a questionnaire describing practice organization, cleaning of the premises, screening of high-risk patients was completed on site and observation of the premises). RESULTS Data collection started in December 2019 and was discontinued due to the national lockdown related to the global SARS-CoV-2 pandemic. Eighty-two practices were analyzed. A hydroalcoholic solution was available in 7.3% of practices and surgical masks in 1.2%. In a majority of waiting rooms, the minimum distance between chairs facing each other was >2 m (78.0%), but was more frequently 1 m for chairs at 90° (53.7%). Overall, 79.3% of waiting rooms could be properly ventilated and waste bins were present in 23.9% of cases. A cleaning protocol was reported in 39.2% of practices. CONCLUSION The COVID-19 epidemic allowed the national dissemination of standard precautions. It will be interesting to monitor over the next few years whether the renewed consideration of standard precautions to prevent viral cross-contamination will be maintained over time.
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Affiliation(s)
- Guillaume Daubert
- Department of Family Medicine, Normandy Rouen University, Rouen, France
| | - Gregoire Gillet
- Department of Family Medicine, Normandy Rouen University, Rouen, France
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Ye J, Qian H, Ma J, Zhou R, Zheng X. Using air curtains to reduce short-range infection risk in consulting ward: A numerical investigation. BUILDING SIMULATION 2021; 14:325-335. [PMID: 32837690 PMCID: PMC7317245 DOI: 10.1007/s12273-020-0649-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 05/05/2023]
Abstract
UNLABELLED Air curtains is promising in reducing the short-range infection risk in hospitals. To quantitatively evaluate its performance, this paper explores air curtains equipped on normal consulting desk to avoid doctor's direct exposure to the patient exhaled pollutants. A numerical investigation is conducted to evaluate the effects of supply air velocity and angle on cutting off performance. Simulation results show that the average mass fraction of exhaled pollutants decreases significantly (70%-90%) in the consulting ward, indicating satisfying performance of air curtains. Increasing supply air velocity is demonstrated to be conducive in forming full air curtains, whereas an excessively high supply air velocity may be of adverse effects by entraining exhaled flow. Besides, the supply air angle is also critical due to its coupling with supply air velocity. It is found that larger angle (0°-40°) is better where velocity is less than 3 m/s, otherwise a small angle (20°) is preferable where velocity is larger than 3 m/s. Exhaled flow could be well suppressed at the supply air angle 20° but moves over air curtains at 40°. This study can provide effective and intuitive guidance in applying air curtains in consulting wards. ELECTRONIC SUPPLEMENTARY MATERIAL ESM Supplementary material is available in the online version of this article at 10.1007/s12273-020-0649-7. The ESM files include the animation of patient exhaled droplets from the droplet birth at 0 s to 5 s under the supply air angle 0°, 20°, 40°, at supply air velocity 3 m/s.
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Affiliation(s)
- Jin Ye
- School of Energy and Environment, Southeast University, Nanjing, 210096 China
- Engineering Research Center of BEEE, Ministry of Education of China, Nanjing, 210096 China
| | - Hua Qian
- School of Energy and Environment, Southeast University, Nanjing, 210096 China
- Engineering Research Center of BEEE, Ministry of Education of China, Nanjing, 210096 China
| | - Jianchao Ma
- School of Energy and Environment, Southeast University, Nanjing, 210096 China
- Engineering Research Center of BEEE, Ministry of Education of China, Nanjing, 210096 China
| | - Rong Zhou
- First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510000 China
- Guangzhou Angel Biosafety Co., Ltd, Guangzhou, 510000 China
| | - Xiaohong Zheng
- School of Energy and Environment, Southeast University, Nanjing, 210096 China
- Engineering Research Center of BEEE, Ministry of Education of China, Nanjing, 210096 China
- Jiangsu Provincial Key Laboratory of Solar Energy Science and Technology, Nanjing, 210096 China
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23
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Culture Media and Sampling Collection Method for Aspergillus spp. Assessment: Tackling the Gap between Recommendations and the Scientific Evidence. ATMOSPHERE 2020. [DOI: 10.3390/atmos12010023] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Culturing is still the most widely used method for determining fungal growth. Thus, is important to identify the most suitable culture media to assess Aspergillus spp. The aim of this study was to analyze data obtained from previous studies, aiming at identifying the most suitable culture media (malt extract agar (MEA) or dichloran-glycerol agar (DG18) to assess Aspergillus spp. isolation and growth. This study was conducted by using environmental samples (n = 1153). Most of the active sampling methods (air samples) were impacted directly onto both culture media. As for passive sampling methods, fungi were extracted from environmental matrices inoculated onto both media. Overall, total Aspergillus counts were higher in MEA (n = 617, 53.5%) than in DG18 (n = 536, 46.5%). Regarding Aspergillus sections, significant associations were detected with the media (χ2 (7) = 241.118, p < 0.001), the sampling approach (p < 0.001, 95% CI = (0.3 × 10−4), and the indoor environment (p < 0.001, 95% CI = (0.3 × 10−4)). As such, sampling approach and the culture media should be accurately selected when dealing with Aspergillus spp. exposure assessment.
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Mehri R, Alatrash A, Ogrodnik N, Matida EA, Fiorenza F. In vitro investigation of the Flusso™ Bypass adapter efficiency upon ventilator circuit disconnect in a clinical simulated environment. ACTA ACUST UNITED AC 2020; 56:86-91. [PMID: 33313385 PMCID: PMC7724989 DOI: 10.29390/cjrt-2020-033] [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] [Indexed: 11/29/2022]
Abstract
Rationale Mechanically ventilated patients must be disconnected from the ventilator during intra-facility transfers. Intentional and accidental circuit disconnections represent a potential hazard to patients (sudden collapse and re-expansion of the alveoli) as well as to clinical staff (exposure to patient’s unfiltered exhalation). Therefore, avoiding abrupt circuit disconnections could better protect the patient’s health and reduce or eliminate contamination risks around clinical staff. Objective The purpose of this in-vitro work was to investigate and evaluate the potential for environmental exposure of Nitric Oxide (NO, as an indicator of any contamination exposure) before and after implementing the novel Flusso™ Bypass adapter during the disconnect procedure of a mechanical ventilator system. Methods A mechanical ventilator delivering NO was connected to a breathing simulator with and without the Flusso™ Bypass adapter. The ambient NO concentration was measured when the circuit was briefly disconnected (3 s) during inhalation and exhalation. Both volume and pressure ventilation modes were used. Measurements and main results Disconnecting the standard ventilator circuit (pressure-controlled mode) without the Flusso™ Bypass adapter produced higher NO escape to the surroundings (compared with the volume-controlled mode), leading to a longer NO dissipation time. No ambient NO traces were detected when the Flusso™ adapter was used. Conclusion The usage of the Flusso™ adapter drastically decreases the unwanted exposure among clinical staff dealing with potentially hazardous airborne biological aerosols emanating from the circuit. Avoiding abrupt disconnection in the ventilator circuit could reduce lung injuries and alveolar over distension and collapse.
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Affiliation(s)
- Rym Mehri
- Department of Mechanical & Aerospace Engineering, Carleton University, Ottawa, ON, Canada
| | - Abubakar Alatrash
- Department of Mechanical & Aerospace Engineering, Carleton University, Ottawa, ON, Canada
| | - Nick Ogrodnik
- Department of Mechanical & Aerospace Engineering, Carleton University, Ottawa, ON, Canada
| | - Edgar A Matida
- Department of Mechanical & Aerospace Engineering, Carleton University, Ottawa, ON, Canada
| | - Frank Fiorenza
- Product Development, McArthur Medical Sales Inc., Rockton, ON, Canada.,Respiratory Therapy Department, University of Ottawa Heart Institute, Ottawa, ON, Canada
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25
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Morawska L, Tang JW, Bahnfleth W, Bluyssen PM, Boerstra A, Buonanno G, Cao J, Dancer S, Floto A, Franchimon F, Haworth C, Hogeling J, Isaxon C, Jimenez JL, Kurnitski J, Li Y, Loomans M, Marks G, Marr LC, Mazzarella L, Melikov AK, Miller S, Milton DK, Nazaroff W, Nielsen PV, Noakes C, Peccia J, Querol X, Sekhar C, Seppänen O, Tanabe SI, Tellier R, Tham KW, Wargocki P, Wierzbicka A, Yao M. How can airborne transmission of COVID-19 indoors be minimised? ENVIRONMENT INTERNATIONAL 2020; 142:105832. [PMID: 32521345 PMCID: PMC7250761 DOI: 10.1016/j.envint.2020.105832] [Citation(s) in RCA: 554] [Impact Index Per Article: 138.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/21/2020] [Accepted: 05/21/2020] [Indexed: 05/17/2023]
Abstract
During the rapid rise in COVID-19 illnesses and deaths globally, and notwithstanding recommended precautions, questions are voiced about routes of transmission for this pandemic disease. Inhaling small airborne droplets is probable as a third route of infection, in addition to more widely recognized transmission via larger respiratory droplets and direct contact with infected people or contaminated surfaces. While uncertainties remain regarding the relative contributions of the different transmission pathways, we argue that existing evidence is sufficiently strong to warrant engineering controls targeting airborne transmission as part of an overall strategy to limit infection risk indoors. Appropriate building engineering controls include sufficient and effective ventilation, possibly enhanced by particle filtration and air disinfection, avoiding air recirculation and avoiding overcrowding. Often, such measures can be easily implemented and without much cost, but if only they are recognised as significant in contributing to infection control goals. We believe that the use of engineering controls in public buildings, including hospitals, shops, offices, schools, kindergartens, libraries, restaurants, cruise ships, elevators, conference rooms or public transport, in parallel with effective application of other controls (including isolation and quarantine, social distancing and hand hygiene), would be an additional important measure globally to reduce the likelihood of transmission and thereby protect healthcare workers, patients and the general public.
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Affiliation(s)
- Lidia Morawska
- International Laboratory for Air Quality and Heath (ILAQH), WHO Collaborating Centre for Air Quality and Health, School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.
| | - Julian W Tang
- Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - William Bahnfleth
- Department of Architectural Engineering, The Pennsylvania State University, USA
| | - Philomena M Bluyssen
- Faculty of Architecture and the Built Environment, Delft University of Technology, the Netherlands
| | - Atze Boerstra
- REHVA (Federation of European Heating, Ventilation and Air Conditioning Associations), BBA Binnenmilieu, the Netherlands
| | - Giorgio Buonanno
- Department if Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy
| | - Junji Cao
- Key Lab of Aerosol Chemistry and Physics Chinese Academy of Sciences, Xi'an, Beijing, China
| | - Stephanie Dancer
- Edinburgh Napier University and NHS Lanarkshire, Scotland, United Kingdom
| | - Andres Floto
- Department of Medicine, University of Cambridge, United Kingdom
| | | | - Charles Haworth
- Cambridge Centre for Lung Infection, Royal Papworth Hospital and Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Jaap Hogeling
- International Standards at ISSO, ISSO International Project, the Netherlands
| | | | - Jose L Jimenez
- Department of Chemistry, and Cooperative Institute for Research in Environmental Sciences (CIRES) University of Colorado, Boulder, USA
| | - Jarek Kurnitski
- REHVA Technology and Research Committee, Tallinn University of Technology, Estonia
| | - Yuguo Li
- Department of Mechancal Engineering, Hong Kong University, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Marcel Loomans
- Department of the Built Environment, Eindhoven University of Technology (TU/e), the Netherlands
| | - Guy Marks
- Centre for Air quality Research and evaluation (CAR), University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | | | | | - Arsen Krikor Melikov
- International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Denmark
| | - Shelly Miller
- Mechanical Engineering, University of Colorado, Boulder, USA
| | - Donald K Milton
- Environmental Health, School of Public Health, University of Maryland, USA
| | - William Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
| | - Peter V Nielsen
- Faculty of Engineering and Science, Department of Civil Engineering, Aalborg University, Denmark
| | - Catherine Noakes
- School of Civil Engineering, University of Leeds, United Kingdom
| | | | - Xavier Querol
- Institute of Environmental Assessment and Water Research, Department of Geosciences, Spanish National Research Council, Barcelona, Spain
| | - Chandra Sekhar
- Department of Building, National University of Singapore, Singapore
| | | | | | | | - Kwok Wai Tham
- Department of Building, National University of Singapore, Singapore
| | - Pawel Wargocki
- International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Denmark
| | | | - Maosheng Yao
- College of Environmental Sciences and Engineering, Peking University, Beijing, China
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26
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Assessment of antibiotic resistant coliforms from bioaerosol samples collected above a sewage-polluted river in La Paz, Bolivia. Int J Hyg Environ Health 2020; 228:113494. [DOI: 10.1016/j.ijheh.2020.113494] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/03/2020] [Accepted: 02/18/2020] [Indexed: 01/01/2023]
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27
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Zhang N, Chen W, Chan PT, Yen HL, Tang JWT, Li Y. Close contact behavior in indoor environment and transmission of respiratory infection. INDOOR AIR 2020; 30:645-661. [PMID: 32259319 DOI: 10.1111/ina.12673] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/29/2020] [Accepted: 03/25/2020] [Indexed: 05/05/2023]
Abstract
Close contact was first identified as the primary route of transmission for most respiratory infections in the early 20th century. In this review, we synthesize the existing understanding of the mechanisms of close contact transmission. We focus on two issues: the mechanism of transmission in close contact, namely the transmission of the expired particles between two people, and the physical parameters of close contact that affect the exposure of particles from one individual to another, or how the nature of close contact plays a role in transmission. We propose the existence of three sub-routes of transmission: short-range airborne, large droplets, and immediate body-surface contact. We also distinguish a "body contact," which is defined with an interpersonal distance of zero, from a close contact. We demonstrate herein that the short-range airborne sub-route may be most common. The timescales over which data should be collected to assess the transmission risk during close contact events are much shorter than those required for the distant airborne or fomite routes. The current paucity of high-resolution data over short distances and timescales makes it very difficult to assess the risk of infection in these circumstances.
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Affiliation(s)
- Nan Zhang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Wenzhao Chen
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Pak-To Chan
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Hui-Ling Yen
- School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Julian Wei-Tze Tang
- Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, UK
- Respiratory Sciences, University of Leicester, Leicester, UK
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- School of Public Health, The University of Hong Kong, Hong Kong, China
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Mbareche H, Veillette M, Bilodeau G, Duchaine C. Comparison of the performance of ITS1 and ITS2 as barcodes in amplicon-based sequencing of bioaerosols. PeerJ 2020; 8:e8523. [PMID: 32110484 PMCID: PMC7032056 DOI: 10.7717/peerj.8523] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/07/2020] [Indexed: 12/23/2022] Open
Abstract
This paper presents the performance of two eukaryotic genomic ribosomal regions, ITS1 and ITS2, in describing fungal diversity in aerosol samples using amplicon-based High-Throughput Sequencing (HTS). Composting sites, biomethanization facilities, and dairy farms, all affected by the presence of fungi, were visited to collect air samples. The amplicon-based HTS approach is a target enrichment method that relies on the amplification of a specific target using particular primers before sequencing. Thus, the results are highly dependent on the quality of amplification. For this reason, the authors of this paper used a shotgun metagenomic approach to compare its outcome with the amplicon-based method. Indeed, shotgun metagenomic does not rely on any amplification prior to sequencing, because all genes are sequenced without a specific target. In addition, culture methods were added to the analyses in biomethanization and dairy farms samples to validate their contribution to fungal diversity of aerosols. The results obtained are unequivocal towards ITS1 outperformance to ITS2 in terms of richness, and taxonomic coverage. The differential abundance analysis did demonstrate that some taxa were exclusively detected only by ITS2, and vice-versa for ITS1. However, the shotgun metagenomic approach showed a taxonomic profile more resembling to ITS1 than ITS2. Based on these results, neither of the barcodes evaluated is perfect in terms of distinguishing all species. Using both barcodes offers a broader view of the fungal aerosol population. However, with the actual knowledge, the authors strongly recommend using ITS1 as a universal fungal barcode for quick general analyses of diversity and when limited financial resources are available, primarily due its ability to capture taxonomic profiles similar to those obtained using the shotgun metagenomic. The culture comparison with amplicon-based sequencing showed the complementarity of both approaches in describing the most abundant taxa.
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Affiliation(s)
- Hamza Mbareche
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Quebec, Canada
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Canada
| | - Marc Veillette
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Quebec, Canada
| | - Guillaume Bilodeau
- Canadian Food Inspection Agency, Pathogen Identification Research Lab, Ottawa, Canada
| | - Caroline Duchaine
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, Quebec, Canada
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, Canada
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29
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Indoor air quality in health care facilities: a call for a concerted multidisciplinary effort. ASIAN BIOMED 2019. [DOI: 10.1515/abm-2019-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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30
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Mbareche H, Veillette M, Pilote J, Létourneau V, Duchaine C. Bioaerosols Play a Major Role in the Nasopharyngeal Microbiota Content in Agricultural Environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16081375. [PMID: 30995814 PMCID: PMC6518280 DOI: 10.3390/ijerph16081375] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/09/2019] [Accepted: 04/13/2019] [Indexed: 12/21/2022]
Abstract
Background: Bioaerosols are a major concern for public health and sampling for exposure assessment purposes is challenging. The nasopharyngeal region could be a potent carrier of long-term bioaerosol exposure agents. This study aimed to evaluate the correlation between nasopharyngeal bacterial flora of swine workers and the swine barns bioaerosol biodiversity. Methods: Air samples from eight swine barns as well as nasopharyngeal swabs from pig workers (n = 25) and from a non-exposed control group (n = 29) were sequenced using 16S rRNA gene high-throughput sequencing. Wastewater treatment plants were used as the industrial, low-dust, non-agricultural environment control to validate the microbial link between the bioaerosol content (air) and the nasopharynxes of workers. Results: A multivariate analysis showed air samples and nasopharyngeal flora of pig workers cluster together, compared to the non-exposed control group. The significance was confirmed with the PERMANOVA statistical test (p-value of 0.0001). Unlike the farm environment, nasopharynx samples from wastewater workers did not cluster with air samples from wastewater treatment plants. The difference in the microbial community of nasopharynx of swine workers and a control group suggest that swine workers are carriers of germs found in bioaerosols. Conclusion: Nasopharynx sampling and microbiota could be used as a proxy of air sampling for exposure assessment studies or for the determination of exposure markers in highly contaminated agricultural environments.
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Affiliation(s)
- Hamza Mbareche
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec G1V 4G5, Canada.
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec G1V 0A6, Canada.
| | - Marc Veillette
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec G1V 4G5, Canada.
| | - Jonathan Pilote
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec G1V 4G5, Canada.
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec G1V 0A6, Canada.
| | - Valérie Létourneau
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec G1V 4G5, Canada.
| | - Caroline Duchaine
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec G1V 4G5, Canada.
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec G1V 0A6, Canada.
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Prakash H, Singh S, Rudramurthy SM, Singh P, Mehta N, Shaw D, Ghosh AK. An aero mycological analysis of Mucormycetes in indoor and outdoor environments of northern India. Med Mycol 2019; 58:118-123. [DOI: 10.1093/mmy/myz031] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/06/2019] [Accepted: 03/15/2019] [Indexed: 11/14/2022] Open
Abstract
Abstract
Mucormycosis is an angio-invasive infection, predominantly acquired by inhalation of sporangiospores from the environment. However, the burden of Mucormycetes sporangiospores in the air is not well studied. We aimed to estimate the burden of Mucormycetes spores in the outdoor and indoor (hospital) environment across different seasons in north India. A total of 380 air samples from outdoor (n = 180) and indoor (n = 200) environment were included in the study. Air samples were suctioned using air sampler (100 l/min) and cultured on Dichloran Rose Bengal Chloramphenicol (DRBC) with benomyl for selective isolation of Mucormycetes. The isolates were identified by phenotypic and genotypic methods. The mean spore count (±SD) of Mucormycetes (cfu/m3) in outdoor samples varied from 0.73 (±0.96) to 8.60 (±5.70) across different seasons. In hospital, the mean spore count varied from 0.68 (±1.07) to 1.12 (±1.07) and 0.88 (±1.01) to 1.72 (±2.17) for air-conditioned wards and non-air-conditioned wards, respectively. Rhizopus arrhizus was the predominant agent isolated from both indoor and outdoor environment followed by Cunninghamella species. We also report a single isolate of the rare mucormycete agent, Apophysomyces variabilis from outdoor environment. The present study highlights the presence of low spore burden of Mucormycetes in outdoor and hospital settings in north India. This study also reports the first isolation of A. variabilis from air samples in the Indian subcontinent.
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Affiliation(s)
- Hariprasath Prakash
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Shreya Singh
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | | | - Pankaj Singh
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Neha Mehta
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Dipika Shaw
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Anup Kumar Ghosh
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Hui DS, Chow BK, Lo T, Tsang OTY, Ko FW, Ng SS, Gin T, Chan MTV. Exhaled air dispersion during high-flow nasal cannula therapy versus CPAP via different masks. Eur Respir J 2019; 53:13993003.02339-2018. [PMID: 30705129 DOI: 10.1183/13993003.02339-2018] [Citation(s) in RCA: 213] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 01/16/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND High-flow nasal cannula (HFNC) is an emerging therapy for respiratory failure but the extent of exhaled air dispersion during treatment is unknown. We examined exhaled air dispersion during HFNC therapy versus continuous positive airway pressure (CPAP) on a human patient simulator (HPS) in an isolation room with 16 air changes·h-1. METHODS The HPS was programmed to represent different severity of lung injury. CPAP was delivered at 5-20 cmH2O via nasal pillows (Respironics Nuance Pro Gel or ResMed Swift FX) or an oronasal mask (ResMed Quattro Air). HFNC, humidified to 37°C, was delivered at 10-60 L·min-1 to the HPS. Exhaled airflow was marked with intrapulmonary smoke for visualisation and revealed by laser light-sheet. Normalised exhaled air concentration was estimated from the light scattered by the smoke particles. Significant exposure was defined when there was ≥20% normalised smoke concentration. RESULTS In the normal lung condition, mean±sd exhaled air dispersion, along the sagittal plane, increased from 186±34 to 264±27 mm and from 207±11 to 332±34 mm when CPAP was increased from 5 to 20 cmH2O via Respironics and ResMed nasal pillows, respectively. Leakage from the oronasal mask was negligible. Mean±sd exhaled air distances increased from 65±15 to 172±33 mm when HFNC was increased from 10 to 60 L·min-1. Air leakage to 620 mm occurred laterally when HFNC and the interface tube became loose. CONCLUSION Exhaled air dispersion during HFNC and CPAP via different interfaces is limited provided there is good mask interface fitting.
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Affiliation(s)
- David S Hui
- Dept of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,Stanley Ho Center for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Benny K Chow
- Stanley Ho Center for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Thomas Lo
- Dept of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Owen T Y Tsang
- Dept of Medicine, Princess Margaret Hospital, Hong Kong, Hong Kong SAR, China
| | - Fanny W Ko
- Dept of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Susanna S Ng
- Dept of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Tony Gin
- Dept of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Matthew T V Chan
- Dept of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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Shajahan A, Culp CH, Williamson B. Effects of indoor environmental parameters related to building heating, ventilation, and air conditioning systems on patients' medical outcomes: A review of scientific research on hospital buildings. INDOOR AIR 2019; 29:161-176. [PMID: 30588679 PMCID: PMC7165615 DOI: 10.1111/ina.12531] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 12/10/2018] [Accepted: 12/21/2018] [Indexed: 05/04/2023]
Abstract
The indoor environment of a mechanically ventilated hospital building controls infection rates as well as influences patients' healing processes and overall medical outcomes. This review covers the scientific research that has assessed patients' medical outcomes concerning at least one indoor environmental parameter related to building heating, ventilation, and air conditioning (HVAC) systems, such as indoor air temperature, relative humidity, and indoor air ventilation parameters. Research related to the naturally ventilated hospital buildings was outside the scope of this review article. After 1998, a total of 899 papers were identified that fit the inclusion criteria of this study. Of these, 176 papers have been included in this review to understand the relationship between the health outcomes of a patient and the indoor environment of a mechanically ventilated hospital building. The purpose of this literature review was to summarize how indoor environmental parameters related to mechanical ventilation systems of a hospital building are impacting patients. This review suggests that there is a need for future interdisciplinary collaborative research to quantify the optimum range for HVAC parameters considering airborne exposures and patients' positive medical outcomes.
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Affiliation(s)
- Amreen Shajahan
- Energy Systems LaboratoryTexas A&M UniversityCollege StationTexas
- Department of ArchitectureTexas A&M UniversityCollege StationTexas
| | - Charles H. Culp
- Energy Systems LaboratoryTexas A&M UniversityCollege StationTexas
- Department of ArchitectureTexas A&M UniversityCollege StationTexas
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Villafruela JM, Olmedo I, Berlanga FA, Ruiz de Adana M. Assessment of displacement ventilation systems in airborne infection risk in hospital rooms. PLoS One 2019; 14:e0211390. [PMID: 30699182 PMCID: PMC6353581 DOI: 10.1371/journal.pone.0211390] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/11/2019] [Indexed: 01/07/2023] Open
Abstract
Efficient ventilation in hospital airborne isolation rooms is important vis-à-vis decreasing the risk of cross infection and reducing energy consumption. This paper analyses the suitability of using a displacement ventilation strategy in airborne infection isolation rooms, focusing on health care worker exposure to pathogens exhaled by infected patients. The analysis is mainly based on numerical simulation results obtained with the support of a 3-D transient numerical model validated using experimental data. A thermal breathing manikin lying on a bed represents the source patient and another thermal breathing manikin represents the exposed individual standing beside the bed and facing the patient. A radiant wall represents an external wall exposed to solar radiation. The air change efficiency index and contaminant removal effectiveness indices and inhalation by the health care worker of contaminants exhaled by the patient are considered in a typical airborne infection isolation room set up with three air renewal rates (6 h-1, 9 h-1 and 12 h-1), two exhaust opening positions and two health care worker positions. Results show that the radiant wall significantly affects the air flow pattern and contaminant dispersion. The lockup phenomenon occurs at the inhalation height of the standing manikin. Displacement ventilation renews the air of the airborne isolation room and eliminates the exhaled pollutants efficiently, but is at a disadvantage compared to other ventilation strategies when the risk of exposure is taken into account.
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Affiliation(s)
| | - Inés Olmedo
- Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Córdoba, Spain
| | - Félix A. Berlanga
- Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Córdoba, Spain
| | - Manuel Ruiz de Adana
- Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Córdoba, Spain
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Qin T, Zhang F, Zhou H, Ren H, Du Y, Liang S, Wang F, Cheng L, Xie X, Jin A, Wu Y, Zhao J, Xu J. High-Level PM2.5/PM10 Exposure Is Associated With Alterations in the Human Pharyngeal Microbiota Composition. Front Microbiol 2019; 10:54. [PMID: 30804895 PMCID: PMC6379047 DOI: 10.3389/fmicb.2019.00054] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/14/2019] [Indexed: 12/21/2022] Open
Abstract
Previous studies showed that high concentration of particulate matter (PM) 2.5 and PM10 carried a large number of bacterial and archaeal species, including pathogens and opportunistic pathogens. In this study, pharyngeal swabs from 83 subjects working in an open air farmer's market were sampled before and after exposure to smog with PM2.5 and PM10 levels up to 200 and 300 μg/m3, respectively. Their microbiota were investigated using high-throughput sequencing targeting the V3-V4 regions of the 16S rRNA gene. The genus level phylotypes was increased from 649 to 767 in the post-smog pharyngeal microbiota, of which 142 were new and detected only in the post-smog microbiota. The 142 new genera were traced to sources such as soil, marine, feces, sewage sludge, freshwater, hot springs, and saline lakes. The abundance of the genera Streptococcus, Haemophilus, Moraxella, and Staphylococcus increased in the post-smog pharyngeal microbiota. All six alpha diversity indices and principal component analysis showed that the taxonomic composition of the post-smog pharyngeal microbiota was significantly different to that of the pre-smog pharyngeal microbiota. Redundancy analysis showed that the influences of PM2.5/PM10 exposure and smoking on the taxonomic composition of the pharyngeal microbiota were statistically significant (p < 0.001). Two days of exposure to high concentrations of PM2.5/PM10 changed the pharyngeal microbiota profiles, which may lead to an increase in respiratory diseases. Wearing masks could reduce the effect of high-level PM2.5/PM10 exposure on the pharyngeal microbiota.
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Affiliation(s)
- Tian Qin
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Beijing, China
- Shanghai Public Health Clinical Center, Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai, China
| | - Furong Zhang
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Haijian Zhou
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Beijing, China
- Shanghai Public Health Clinical Center, Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai, China
| | - Hongyu Ren
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yinju Du
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Shengnan Liang
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Fei Wang
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Lihong Cheng
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Xuguang Xie
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Aoming Jin
- Peking University Clinical Research Institute, Beijing, China
| | - Yangfeng Wu
- Peking University Clinical Research Institute, Beijing, China
| | - Jinxing Zhao
- Centre for Disease Control and Prevention of Liaocheng, Liaocheng, China
| | - Jianguo Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Beijing, China
- Shanghai Public Health Clinical Center, Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai, China
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Bioaerosol Sampler Choice Should Consider Efficiency and Ability of Samplers To Cover Microbial Diversity. Appl Environ Microbiol 2018; 84:AEM.01589-18. [PMID: 30217848 DOI: 10.1128/aem.01589-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/12/2018] [Indexed: 02/06/2023] Open
Abstract
Bioaerosol studies aim to describe the microbial content and increase understanding of the aerosolization processes linked to diseases. Air samplers are used to collect, identify, and quantify bioaerosols. Studies comparing the performances of air samplers have typically used a culture approach or have targeted a specific microorganism in laboratory settings. The objective of this study was to use environmental field samples to compare the efficiencies of 3 high-airflow-rate samplers for describing bioaerosol diversity using a next-generation sequencing approach. Two liquid cyclonic impactors and one electrostatic filter dry sampler were used in four wastewater treatment plants to target bacterial diversity and in five dairy farms to target fungal diversity. The dry electrostatic sampler was consistently more powerful in collecting more fungal and bacterial operational taxonomic units (OTUs). Substantial differences in OTU abundances between liquid and dry sampling were revealed. The majority of the diversity revealed by dry electrostatic sampling was not identified using the cyclonic liquid impactors. The findings from this work suggest that the choice of a bioaerosol sampler should include information about the efficiency and ability of samplers to cover microbial diversity. Although these results suggest that electrostatic filters result in better coverage of the microbial diversity among the tested air samplers, further studies are needed to confirm this hypothesis. While it is difficult to determine a single universally optimal air sampler, this work provides an in-depth look at some of the considerations that are essential when choosing an air sampler for studying the microbial ecology of bioaerosols.IMPORTANCE Associating bioaerosol exposure and health problems is challenging, and adequate exposure monitoring is a priority for scientists in the field. Conclusions that can be drawn from bioaerosol exposure studies are highly dependent on the design of the study and the methodologies used. The air sampling strategy is the first methodological step leading to an accurate interpretation of what is present in the air. Applying new molecular approaches to evaluate the efficiencies of the different types of samplers used in the field is necessary in order to circumvent traditional approaches and the biases they introduce to such studies. The results and conclusions provided in this paper should be taken in consideration when conducting a bioaerosol study.
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Leung CCH, Joynt GM, Gomersall CD, Wong WT, Lee A, Ling L, Chan PKS, Lui PCW, Tsoi PCY, Ling CM, Hui M. Comparison of high-flow nasal cannula versus oxygen face mask for environmental bacterial contamination in critically ill pneumonia patients: a randomized controlled crossover trial. J Hosp Infect 2018; 101:84-87. [PMID: 30336170 DOI: 10.1016/j.jhin.2018.10.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 10/09/2018] [Indexed: 11/17/2022]
Abstract
Whereas high-flow nasal cannula use is gaining prevalence, its high gas flow raises concerns about aerosolization of infectious particles and spread of infection. This randomized controlled crossover non-inferiority trial (N = 20) evaluated the degree of environmental contamination by viable bacteria associated with the use of high-flow nasal cannula compared with conventional oxygen mask for critically ill patients with Gram-negative pneumonia. The results show that high-flow nasal cannula use was not associated with increased air or contact surface contamination by either Gram-negative bacteria or total bacteria, suggesting that additional infection control measures are not required.
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Affiliation(s)
- C C H Leung
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong
| | - G M Joynt
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong.
| | - C D Gomersall
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong
| | - W T Wong
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong
| | - A Lee
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong
| | - L Ling
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong
| | - P K S Chan
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong
| | - P C W Lui
- Department of Pathology, Union Hospital, Hong Kong
| | - P C Y Tsoi
- Department of Pathology, Union Hospital, Hong Kong
| | - C M Ling
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong
| | - M Hui
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong
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Ghanizadeh F, Godini H. A review of the chemical and biological pollutants in indoor air in hospitals and assessing their effects on the health of patients, staff and visitors. REVIEWS ON ENVIRONMENTAL HEALTH 2018; 33:231-245. [PMID: 30074898 DOI: 10.1515/reveh-2018-0011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/07/2018] [Indexed: 05/14/2023]
Abstract
Abstract
Indoor air quality in hospitals has been specifically considered in terms of its impact on health. Air quality is an important risk factor influencing the health of staff and patients who are in contact with indoor air inhaled in hospitals. Over the past two decades, hundreds of studies have been developed to assess pollution in hospital environment. Two hundred and fitfy papers from around the world, from the last two decades, were identified and reviewed. Recent studies have found that the presence of various chemical and biological pollutants affected the health of patients, staff and visitors. Nearly all the reports agree that chemical and biological pollutants in the hospital environment have adverse effects. In most of the reviewed papers, analysis of health hazards was conducted for personnel and patients to toxic metals, chlorine, fine (PM2.5) and coarse (PM2.5−10) particles, and bio-aerosol in the inhaled air of the hospital environment. Some papers showed that some of the metals are carcinogens and others do not have a carcinogenic risk. Bio-aerosols as a biological pollutant are usually defined as airborne bacteria, fungi, viruses, pollen and their by products. These biological pollutants are associated with a wide range of health effects in hospital environments. This review can serve as an introduction and as the statement of the problem for more original research in this regard.
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Affiliation(s)
- Fatemeh Ghanizadeh
- Lorestan University of Medical Sciences University, Integrated Higher Education of Health of Doroud, Khorramabad, Iran
| | - Hatam Godini
- Associated Prof, Research Center for Health, Safety and Environment, Alborz University of Medical Sciences, Karaj, Iran
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Abiola I, Abass A, Duodu S, Mosi L. Characterization of culturable airborne bacteria and antibiotic susceptibility profiles of indoor and immediate-outdoor environments of a research institute in Ghana. AAS Open Res 2018; 1:17. [PMID: 32259019 PMCID: PMC7118738 DOI: 10.12688/aasopenres.12863.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2018] [Indexed: 12/11/2022] Open
Abstract
Background: The study was conducted to determine the bacterial composition and antibiotic susceptibility profiles of a research institute at the University of Ghana where workers and students spend about 70-85% of their lives in indoor and immediate-outdoor environments. This is imperative as one-third of the recognized infectious diseases are transmitted through airborne-route. Furthermore, the increasing rate of bacterial antimicrobial resistance associated with such environments poses serious public health challenges. Methods: A total of 42 airborne samples were collected from eight major sites at the Department of Biochemistry, Cell and Molecular Biology (BCMB), using passive bacterial sampling techniques. Standard phenotypic microbiological procedures were used to characterize the isolates. Antibiotic susceptibility profiles were determined using standard disk diffusion method and guidelines of Clinical and Laboratory Standards Institute (CLSI). Results: Four groups of bacterial isolates were identified from the total samples collected with Gram positive bacilli as the most common. All the isolates showed resistance to beta lactam and sulfonamide classes of antibiotics with full resistance (100%) to ampicillin and penicillin. In total, seven different anti-biotypes were observed with the highest susceptibility displayed towards tetracycline and gentamycin. Significantly, the various air sampling sites of the institute indicated the presence of bacteria with the majority showing multiple antibiotics resistance. Conclusions: Although the recovery of bacteria from supposed sterile environments calls for attention, the observed low contamination rate as compared to the WHO standard suggests a minimum risk of exposure of students and workers to airborne microbial contamination.
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Affiliation(s)
- Isawumi Abiola
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) , University of Ghana, Accra, LG 54 , Ghana.,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, LG 54, Ghana
| | - Adiza Abass
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) , University of Ghana, Accra, LG 54 , Ghana.,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, LG 54, Ghana
| | - Samuel Duodu
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) , University of Ghana, Accra, LG 54 , Ghana.,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, LG 54, Ghana
| | - Lydia Mosi
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) , University of Ghana, Accra, LG 54 , Ghana.,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, LG 54, Ghana
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40
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Pinter-Wollman N, Jelić A, Wells NM. The impact of the built environment on health behaviours and disease transmission in social systems. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170245. [PMID: 29967306 PMCID: PMC6030577 DOI: 10.1098/rstb.2017.0245] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2018] [Indexed: 01/08/2023] Open
Abstract
The environment plays an important role in disease dynamics and in determining the health of individuals. Specifically, the built environment has a large impact on the prevention and containment of both chronic and infectious disease in humans and in non-human animals. The effects of the built environment on health can be direct, for example, by influencing environmental quality, or indirect by influencing behaviours that impact disease transmission and health. Furthermore, these impacts can happen at many scales, from the individual to the society, and from the design of the plates we eat from to the design of cities. In this paper, we review the ways that the built environment affects both the prevention and the containment of chronic and infectious disease. We bring examples from both human and animal societies and attempt to identify parallels and gaps between the study of humans and animals that can be capitalized on to advance the scope and perspective of research in each respective field. By consolidating this literature, we hope to highlight the importance of built structures in determining the complex dynamics of disease and in impacting the health behaviours of both humans and animals.This article is part of the theme issue 'Interdisciplinary approaches for uncovering the impacts of architecture on collective behaviour'.
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Affiliation(s)
- Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Andrea Jelić
- Department of Architecture, Design and Media Technology, Aalborg University, 9000 Aalborg, Denmark
| | - Nancy M Wells
- Department of Design and Environmental Analysis, Cornell University, Ithaca, NY 14853, USA
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41
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Ai ZT, Melikov AK. Airborne spread of expiratory droplet nuclei between the occupants of indoor environments: A review. INDOOR AIR 2018; 28:500-524. [PMID: 29683213 DOI: 10.1111/ina.12465] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 04/13/2018] [Indexed: 05/04/2023]
Abstract
This article reviews past studies of airborne transmission between occupants in indoor environments, focusing on the spread of expiratory droplet nuclei from mouth/nose to mouth/nose for non-specific diseases. Special attention is paid to summarizing what is known about the influential factors, the inappropriate simplifications of the thermofluid boundary conditions of thermal manikins, the challenges facing the available experimental techniques, and the limitations of available evaluation methods. Secondary issues are highlighted, and some new ways to improve our understanding of airborne transmission indoors are provided. The characteristics of airborne spread of expiratory droplet nuclei between occupants, which are influenced correlatively by both environmental and personal factors, were widely revealed under steady-state conditions. Owing to the different boundary conditions used, some inconsistent findings on specific influential factors have been published. The available instrumentation was too slow to provide accurate concentration profiles for time-dependent evaluations of events with obvious time characteristics, while computational fluid dynamics (CFD) studies were mainly performed in the framework of inherently steady Reynolds-averaged Navier-Stokes modeling. Future research needs in 3 areas are identified: the importance of the direction of indoor airflow patterns, the dynamics of airborne transmission, and the application of CFD simulations.
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Affiliation(s)
- Z T Ai
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Copenhagen, Denmark
| | - A K Melikov
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Copenhagen, Denmark
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42
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O'Neil CA, Li J, Leavey A, Wang Y, Hink M, Wallace M, Biswas P, Burnham CAD, Babcock HM. Characterization of Aerosols Generated During Patient Care Activities. Clin Infect Dis 2018; 65:1335-1341. [PMID: 29017249 PMCID: PMC6248660 DOI: 10.1093/cid/cix535] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/16/2017] [Indexed: 12/16/2022] Open
Abstract
Background Questions remain about the degree to which aerosols are generated during routine patient care activities and whether such aerosols could transmit viable pathogens to healthcare personnel (HCP). The objective of this study was to measure aerosol production during multiple patient care activities and to examine the samples for bacterial pathogens. Methods Five aerosol characterization instruments were used to measure aerosols during 7 patient care activities: patient bathing, changing bed linens, pouring and flushing liquid waste, bronchoscopy, noninvasive ventilation, and nebulized medication administration (NMA). Each procedure was sampled 5 times. An SKC BioSampler was used for pathogen recovery. Bacterial cultures were performed on the sampling solution. Patients on contact precautions for drug-resistant organisms were selected for most activity sampling. Any patient undergoing bronchoscopy was eligible. Results Of 35 sampling episodes, only 2 procedures showed a significant increase in particle concentrations over baseline: NMA and bronchoscopy with NMA. Bronchoscopy without NMA and noninvasive ventilation did not generate significant aerosols. Of 78 cultures from the impinger samples, 6 of 28 baseline samples (21.4%) and 14 of 50 procedure samples (28.0%) were positive. Conclusions In this study, significant aerosol generation was only observed during NMA, both alone and during bronchoscopy. Minimal viable bacteria were recovered, mostly common environmental organisms. Although more research is needed, these data suggest that some of the procedures considered to be aerosol-generating may pose little infection risk to HCP.
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Affiliation(s)
- Caroline A O'Neil
- Infectious Diseases Division, Washington University School of Medicine, St Louis, MS
| | - Jiayu Li
- School of Engineering and Applied Science, Department of Energy, Environmental, and Chemical Engineering, Aerosol and Air Quality Research Laboratory, Washington University, St Louis, Missouri
| | - Anna Leavey
- School of Engineering and Applied Science, Department of Energy, Environmental, and Chemical Engineering, Aerosol and Air Quality Research Laboratory, Washington University, St Louis, Missouri
| | - Yang Wang
- School of Engineering and Applied Science, Department of Energy, Environmental, and Chemical Engineering, Aerosol and Air Quality Research Laboratory, Washington University, St Louis, Missouri
| | - Matthew Hink
- Infectious Diseases Division, Washington University School of Medicine, St Louis, MS
| | - Meghan Wallace
- School of Medicine, Department of Pathology and Immunology, Washington University, St Louis, Missouri
| | - Pratim Biswas
- School of Engineering and Applied Science, Department of Energy, Environmental, and Chemical Engineering, Aerosol and Air Quality Research Laboratory, Washington University, St Louis, Missouri
| | - Carey-Ann D Burnham
- School of Medicine, Department of Pathology and Immunology, Washington University, St Louis, Missouri
| | - Hilary M Babcock
- Infectious Diseases Division, Washington University School of Medicine, St Louis, MS
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Heredia-Rodríguez M, Álvarez-Fuente E, Bustamante-Munguira J, Poves-Alvarez R, Fierro I, Gómez-Sánchez E, Gómez-Pesquera E, Lorenzo-López M, Eiros JM, Álvarez FJ, Tamayo E. Impact of an ultraviolet air sterilizer on cardiac surgery patients, a randomized clinical trial. Med Clin (Barc) 2018; 151:299-307. [PMID: 29807859 DOI: 10.1016/j.medcli.2018.04.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/16/2018] [Accepted: 04/19/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Numerous studies have evaluated the use of ultraviolet-C devices for terminal disinfection in hospitals, however, to date there is little information about the device's final impact on patients. We investigated the effect of an ultraviolet air sterilizer (UVAS) on the clinical outcomes of cardiac surgery patients. MATERIALS AND METHODS This random, prospective and non-interventional study included 1097 adult patients undergoing elective cardiac surgery: 522 stayed in an ICU room with UVAS (Medixair®) and 575 patients ICU room without UVAS and were used as a control. The primary outcome measure was to evaluate the effect of a UVAS on the overall prevalence of nosocomial infections in postoperative cardiac patients in ICUs. RESULTS No significant differences in ventilator-associated pneumonia (4.6% vs. 5.0%, p=0.77) and total infection (14.0% vs. 15.5%, p=0.45) rates were detected in patients with and without the UVAS. The length of stay in the intensive care unit and at the hospital was similar in both groups, UVAS (4.6 (8.2) days and 18.3 (5.5) days) and without UVAS (4.6 (7.3) days and 19.2 (18.6) days). The 30-day in-hospital mortality rate was 5.3%, no significant differences between groups were observed (p=0.053). CONCLUSION Novel ultraviolet-C technology has not been shown to significantly reduce nosocomial infections or mortality rates in cardiac surgery patients.
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Affiliation(s)
- María Heredia-Rodríguez
- Department of Anaesthesiology, Hospital Clínico Universitario, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain
| | - Elisa Álvarez-Fuente
- Department of Anaesthesiology, Hospital Clínico Universitario, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain
| | | | - Rodrigo Poves-Alvarez
- Department of Anaesthesiology, Hospital Clínico Universitario, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain.
| | - Inmaculada Fierro
- Department of Health Sciences, European University Miguel de Cervantes, Valladolid, Spain
| | - Esther Gómez-Sánchez
- Department of Anaesthesiology, Hospital Clínico Universitario, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain
| | - Estefanía Gómez-Pesquera
- Department of Anaesthesiology, Hospital Clínico Universitario, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain
| | - Mario Lorenzo-López
- Department of Anaesthesiology, Hospital Clínico Universitario, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain
| | - José María Eiros
- Department of Microbiology, Hospital Río Hortega, Valladolid, Spain
| | | | - Eduardo Tamayo
- Department of Pharmacology, University of Valladolid, Valladolid, Spain; BioCritic, Group for Biomedical Research in Critical Care Medicine, Valladolid, Spain
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Abiola I, Abass A, Duodu S, Mosi L. Characterization of culturable airborne bacteria and antibiotic susceptibility profiles of indoor and immediate-outdoor environments of a research institute. AAS Open Res 2018. [DOI: 10.12688/aasopenres.12863.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background:The study was conducted to determine the bacterial composition and antibiotic susceptibility profiles of a research institute at the University of Ghana where workers and students spend about 70-85% of their lives in indoor and immediate-outdoor environments. This is imperative as one-third of the recognized infectious diseases are transmitted through airborne-route. Furthermore, the increasing rate of bacterial antimicrobial resistance associated with such environments poses serious public health challenges.Methods:A total of 42 airborne samples were collected from eight major sites at the Department of Biochemistry, Cell and Molecular Biology (BCMB), using passive bacterial sampling techniques. Standard phenotypic microbiological procedures were used to characterize the isolates. Antibiotic susceptibility profiles were determined using standard disk diffusion method and guidelines of Clinical and Laboratory Standards Institute (CLSI).Results:Four groups of bacterial isolates were identified from the total samples collected with Gram positive bacilli as the most common. All the isolates showed resistance to beta lactam and sulfonamide classes of antibiotics with full resistance (100%) to ampicillin and penicillin. In total, seven different anti-biotypes were observed with the highest susceptibility displayed towards tetracycline and gentamycin. Significantly, the various air sampling sites of the institute indicated the presence of bacteria with the majority showing multiple antibiotics resistance.Conclusions:Although the recovery of bacteria from supposed sterile environments calls for attention, the observed low contamination rate as compared to the WHO standard suggests a minimum risk of exposure of students and workers to airborne microbial contamination.
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45
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Tanaka Y, Fujino K, Larkins GA, Osawa A, Hayashi Y, Taharaguchi S. Preventing the spread of norovirus-like infections by the airborne route using plasma assisted catalytic technology (PACT). J Vet Med Sci 2018; 80:1459-1462. [PMID: 29709903 PMCID: PMC6160878 DOI: 10.1292/jvms.17-0695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Zoonoses are frequently reported, and outbreaks of the highly pathogenic influenza virus, severe acute respiratory syndrome, and Middle East respiratory syndrome have occurred recently, in Africa, the Middle East, and Southeast Asia. Sterilization using a chemical reactor with plasma assisted catalytic technology (PACT) was investigated. Tests were carried out on the feline calicivirus (FCV) vaccine strain F9, which is a surrogate of airborne pathogen human norovirus. Results showed that the PACT device could inactivate FCV, which passed through the plasma chamber. Sterilization rate may be more than 99.99% (below the detection limit). These results indicate that PACT may be an effective mean to inactivate many viruses, including human norovirus, and potentially other airborne, infectious microorganisms.
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Affiliation(s)
- Yoshimoto Tanaka
- Laboratory of Microbiology II, Department of Veterinary Medicine, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan
| | - Kan Fujino
- Laboratory of Microbiology II, Department of Veterinary Medicine, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan
| | - Gerald Andrew Larkins
- Faculty of Engineering-Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan
| | - Atsushi Osawa
- I'm PACT World Ltd., 302 Apartment Kaya, 2-42-5, Den-en Choufu, Ota-ku, Tokyo 145-0071, Japan
| | - Yuji Hayashi
- I'm PACT World Ltd., 302 Apartment Kaya, 2-42-5, Den-en Choufu, Ota-ku, Tokyo 145-0071, Japan
| | - Satoshi Taharaguchi
- Laboratory of Microbiology II, Department of Veterinary Medicine, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan
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46
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Abrego N, Norros V, Halme P, Somervuo P, Ali-Kovero H, Ovaskainen O. Give me a sample of air and I will tell which species are found from your region: Molecular identification of fungi from airborne spore samples. Mol Ecol Resour 2018; 18:511-524. [PMID: 29330936 DOI: 10.1111/1755-0998.12755] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 11/26/2022]
Abstract
Fungi are a megadiverse group of organisms, they play major roles in ecosystem functioning and are important for human health, food production and nature conservation. Our knowledge on fungal diversity and fungal ecology is however still very limited, in part because surveying and identifying fungi is time demanding and requires expert knowledge. We present a method that allows anyone to generate a list of fungal species likely to occur in a region of interest, with minimal effort and without requiring taxonomical expertise. The method consists of using a cyclone sampler to acquire fungal spores directly from the air to an Eppendorf tube, and applying DNA barcoding with probabilistic species identification to generate a list of species from the sample. We tested the feasibility of the method by acquiring replicate air samples from different geographical regions within Finland. Our results show that air sampling is adequate for regional-level surveys, with samples collected >100 km apart varying but samples collected <10 km apart not varying in their species composition. The data show marked phenology, and thus obtaining a representative species list requires aerial sampling that covers the entire fruiting season. In sum, aerial sampling combined with probabilistic molecular species identification offers a highly effective method for generating a species list of air-dispersing fungi. The method presented here has the potential to revolutionize fungal surveys, as it provides a highly cost-efficient way to include fungi as a part of large-scale biodiversity assessments and monitoring programs.
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Affiliation(s)
- Nerea Abrego
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Veera Norros
- Department of Biosciences, University of Helsinki, Helsinki, Finland.,Marine Research Centre, Finnish Environment Institute, Helsinki, Finland
| | - Panu Halme
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Panu Somervuo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Heini Ali-Kovero
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Otso Ovaskainen
- Department of Biosciences, University of Helsinki, Helsinki, Finland.,Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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47
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Liu H, Zhang X, Zhang H, Yao X, Zhou M, Wang J, He Z, Zhang H, Lou L, Mao W, Zheng P, Hu B. Effect of air pollution on the total bacteria and pathogenic bacteria in different sizes of particulate matter. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 233:483-493. [PMID: 29101891 DOI: 10.1016/j.envpol.2017.10.070] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 10/16/2017] [Accepted: 10/17/2017] [Indexed: 05/21/2023]
Abstract
In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the "Human Pathogen Database" was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers.
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Affiliation(s)
- Huan Liu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Xu Zhang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Hao Zhang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Xiangwu Yao
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Meng Zhou
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jiaqi Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Zhanfei He
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Huihui Zhang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Liping Lou
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Weihua Mao
- The Center of Analysis and Measurement, Zhejiang University, Hangzhou, 310058, China
| | - Ping Zheng
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Baolan Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China.
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48
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Ma X, Zhao C, Gao Y, Liu B, Wang T, Yuan T, Hale L, Nostrand JDV, Wan S, Zhou J, Yang Y. Divergent taxonomic and functional responses of microbial communities to field simulation of aeolian soil erosion and deposition. Mol Ecol 2017; 26:4186-4196. [PMID: 28570016 DOI: 10.1111/mec.14194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 04/10/2017] [Accepted: 05/15/2017] [Indexed: 01/09/2023]
Abstract
Aeolian soil erosion and deposition have worldwide impacts on agriculture, air quality and public health. However, ecosystem responses to soil erosion and deposition remain largely unclear in regard to microorganisms, which are the crucial drivers of biogeochemical cycles. Using integrated metagenomics technologies, we analysed microbial communities subjected to simulated soil erosion and deposition in a semiarid grassland of Inner Mongolia, China. As expected, soil total organic carbon and plant coverage were decreased by soil erosion, and soil dissolved organic carbon (DOC) was increased by soil deposition, demonstrating that field simulation was reliable. Soil microbial communities were altered (p < .039) by both soil erosion and deposition, with dramatic increase in Cyanobacteria related to increased stability in soil aggregates. amyA genes encoding α-amylases were specifically increased (p = .01) by soil deposition and positively correlated (p = .02) to DOC, which likely explained changes in DOC. Surprisingly, most of microbial functional genes associated with carbon, nitrogen, phosphorus and potassium cycling were decreased or unaltered by both erosion and deposition, probably arising from acceleration of organic matter mineralization. These divergent responses support the necessity to include microbial components in evaluating ecological consequences. Furthermore, Mantel tests showed strong, significant correlations between soil nutrients and functional structure but not taxonomic structure, demonstrating close relevance of microbial function traits to nutrient cycling.
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Affiliation(s)
- Xingyu Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Cancan Zhao
- State Key Laboratory of Cotton Biology, Key Laboratory of Plant Stress Biology, College of Life Sciences, Henan University, Kaifeng, China
| | - Ying Gao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Bin Liu
- State Key Laboratory of Cotton Biology, Key Laboratory of Plant Stress Biology, College of Life Sciences, Henan University, Kaifeng, China
| | - Tengxu Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Tong Yuan
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Lauren Hale
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Joy D Van Nostrand
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Shiqiang Wan
- State Key Laboratory of Cotton Biology, Key Laboratory of Plant Stress Biology, College of Life Sciences, Henan University, Kaifeng, China
| | - Jizhong Zhou
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.,Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.,Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Yunfeng Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
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49
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Berlanga FA, Olmedo I, Ruiz de Adana M. Experimental analysis of the air velocity and contaminant dispersion of human exhalation flows. INDOOR AIR 2017; 27:803-815. [PMID: 27859708 DOI: 10.1111/ina.12357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 11/11/2016] [Indexed: 05/26/2023]
Abstract
Human exhalation flow is a potential source of pathogens that can constitute a cross-infection risk to people in indoor environments. Thus, it is important to investigate the characteristics of this flow, its development, area of influence, and the diffusion of the exhaled contaminants. This paper uses phase-averaged particle image velocimetry together with a tracer gas (CO2 ) to study two different exhalation flows over time: the exhalation of an average male (test M) and an average female (test F), using a life-sized thermal manikin in a supine position. The exhalation jets generated for both tests are similar in terms of symmetrical geometry, vorticity values, jet opening angles, and velocity and concentration decays. However, there is a difference in the penetration length of the two flows throughout the whole exhalation process. There is also a time difference in reaching maximum velocity between the two tests. It is also possible to see that the tracer gas dispersion depends on the momentum of the jet so the test with the highest velocity decay shows the lowest concentration decay. All these results are of interest to better understand cross-infection risk.
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Affiliation(s)
- F A Berlanga
- Department of Chemical Physics and Applied Thermodynamics, University of Córdoba, Córdoba, Spain
| | - I Olmedo
- Department of Chemical Physics and Applied Thermodynamics, University of Córdoba, Córdoba, Spain
| | - M Ruiz de Adana
- Department of Chemical Physics and Applied Thermodynamics, University of Córdoba, Córdoba, Spain
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50
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Mu D, Shu C, Gao N, Zhu T. Wind tunnel tests of inter-flat pollutant transmission characteristics in a rectangular multi-storey residential building, part B: Effect of source location. BUILDING AND ENVIRONMENT 2017; 114:281-292. [PMID: 32287970 PMCID: PMC7117001 DOI: 10.1016/j.buildenv.2016.12.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/22/2016] [Accepted: 12/23/2016] [Indexed: 05/19/2023]
Abstract
The pollutant behavior in and around a naturally ventilated building requires to be investigated quantitatively as the growing concern on air quality within the built environment. The objective of the present study is to further investigate the wind induced inter-flat pollutant transmission and cross contamination routes in typical buildings in Shanghai. In this paper, a set of experiments was carried out in a boundary layer wind tunnel using a 1:30 reduced scale model that represented the typical configuration of rectangular multi-storey residential buildings. Sulfur hexafluoride (SF6) was employed as a tracer gas in the wind tunnel tests. Two natural ventilation modes, single-sided ventilation and cross ventilation were considered. The conditions under prevailing wind direction with different source locations on the windward side were compared. The pressure coefficients on all of the building façades and tracer gas concentration distributions were monitored and analysed. The experimental results elucidated that contaminant released from windward units could spread vertically and horizontally to other units on the source façade and downstream units. The source location was a significant influence factor on the pollutant concentration in various units. In the single-sided ventilated building, the infected risks of leeward units were even higher than those in some windward units. In the cross ventilated building, the vertical transmission could be suppressed and the horizontal transmission was reinforced. The study is helpful for further understanding of the inter-flat airborne transmission within an isolated building.
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Affiliation(s)
| | | | - Naiping Gao
- School of Mechanical Engineering, Tongji University, Shanghai, China
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