1
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Graf S, Engelmann L, Jeleff Wölfler O, Albrecht I, Schloderer M, Kramer A, Klankermayer L, Gebhardt F, Chaker AM, Spinner CD, Schwab R, Wollenberg B, Protzer U, Hoffmann D. Reopening the Bavarian State Opera Safely: Hygiene Strategies and Incidence of COVID-19 in Artistic Staff During Theater Season 2020/2021. J Voice 2024; 38:798.e7-798.e20. [PMID: 34906415 PMCID: PMC8627642 DOI: 10.1016/j.jvoice.2021.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/07/2021] [Accepted: 11/08/2021] [Indexed: 01/16/2023]
Abstract
Due to the drastically rising coronavirus disease (COVID-19) incidence since March 2020, social life was shut down across the globe, and most opera houses were closed. As a result, there are limited data on SARS-CoV-2 infections among artists. The Bavarian State Opera has been reopened in September 2020. This study aimed to identify the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among employees in the Bavarian State Opera. In addition, the various hygiene strategies for the work groups within the institution are described. During the study period from September 1, 2020 to July 31, 2021, 10,061 nasopharyngeal swabs were obtained from 1,460 artistic staff members in a rolling system. During the entire study period, 61 individuals tested positive for SARS-CoV-2. None of the patients had a severe disease course. Compared to the seven-day-incidence per 100,000 German inhabitants, the estimated corresponding incidence among employees was lower at 37 weeks and higher or equal at 9 weeks. Among the infected individuals, 58.3% were symptomatic, 23.3% were presymptomatic, and 18.3% were asymptomatic. Forty-five percent of employees reported that they had been infected in their private environment, 41.7% suspected that their colleagues were the main contact, and 13.3% were unsure about the origin of their infection. Twenty-four diseased employees were ballet dancers, eight from the orchestra, seven from the administration, seven from the choir singers, six from the costume department, 10 from technical support, and one guest solo singer. In the 2020/2021 theater season, increased SARS-CoV-2 infections and large disease outbreaks were avoided at the Bavarian State Opera. Hygiene strategies, that existed since the beginning, was specifically designed for various work areas in the opera. Regular, mandatory PCR testing and follow-up of positive cases with the issuance of quarantine were performed. Using this disease management approach, artistic work at and reopening of the Bavarian State Opera was feasible with a well-controlled risk.
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Affiliation(s)
- Simone Graf
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Otorhinolaryngology, Germany.
| | - Luca Engelmann
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Otorhinolaryngology, Germany
| | - Olivia Jeleff Wölfler
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Otorhinolaryngology, Germany
| | | | | | | | - Lucia Klankermayer
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Otorhinolaryngology, Germany
| | - Friedemann Gebhardt
- Technical University of Munich /Helmholtz Center, School of Medicine, Munich, Institute for Medical Microbiology, Immunology and Hygiene, Germany
| | - Adam M Chaker
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Otorhinolaryngology, Germany; Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Center of Allergy and Environment (ZAUM)
| | - Christoph D Spinner
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Internal Medicine II, Germany
| | | | - Barbara Wollenberg
- Technical University of Munich, School of Medicine, Munich, University hospital rechts der Isar, Department of Otorhinolaryngology, Germany
| | - Ulrike Protzer
- Technical University of Munich /Helmholtz Center, School of Medicine, Munich, Institute of Virology, Germany
| | - Dieter Hoffmann
- Technical University of Munich /Helmholtz Center, School of Medicine, Munich, Institute of Virology, Germany
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2
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Tanner K, Good KM, Goble D, Good N, Keisling A, Keller KP, L’Orange C, Morton E, Phillips R, Volckens J. Large Particle Emissions from Human Vocalization and Playing of Wind Instruments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15392-15400. [PMID: 37796739 PMCID: PMC10586367 DOI: 10.1021/acs.est.3c03588] [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: 05/11/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 10/07/2023]
Abstract
Humans emit large salivary particles when talking, singing, and playing musical instruments, which have implications for respiratory disease transmission. Yet little work has been done to characterize the emission rates and size distributions of such particles. This work characterized large particle (dp > 35 μm in aerodynamic diameter) emissions from 70 volunteers of varying age and sex while vocalizing and playing wind instruments. Mitigation efficacies for face masks (while singing) and bell covers (while playing instruments) were also examined. Geometric mean particle count emission rates varied from 3.8 min-1 (geometric standard deviation [GSD] = 3.1) for brass instruments playing to 95.1 min-1 (GSD = 3.8) for talking. On average, talking produced the highest emission rates for large particles, in terms of both number and mass, followed by singing and then instrument playing. Neither age, sex, CO2 emissions, nor loudness (average dBA) were significant predictors of large particle emissions, contrary to previous findings for smaller particle sizes (i.e., for dp < 35 μm). Size distributions were similar between talking and singing (count median diameter = 53.0 μm, GSD = 1.69). Bell covers did not affect large particle emissions from most wind instruments, but face masks reduced large particle count emissions for singing by 92.5% (95% CI: 97.9%, 73.7%).
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Affiliation(s)
- Ky Tanner
- Department
of Mechanical Engineering, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - Kristen M. Good
- Department
of Environmental and Radiological Health Sciences, Colorado State University, Fort
Collins, Colorado 80523, United States
- Colorado
Department of Public Health and Environment, Denver, Colorado 80246, United States
| | - Dan Goble
- School
of Music, Theatre, and Dance, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - Nicholas Good
- Department
of Civil and Environmental Engineering, Colorado State University, Fort
Collins, Colorado 80523, United States
| | - Amy Keisling
- Department
of Mechanical Engineering, Colorado State
University, Fort Collins, Colorado 80523, United States
- School
of Music, Theatre, and Dance, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - Kayleigh P. Keller
- Department
of Statistics, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Christian L’Orange
- Department
of Mechanical Engineering, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - Emily Morton
- School
of Music, Theatre, and Dance, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - Rebecca Phillips
- School
of Music, Theatre, and Dance, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - John Volckens
- Department
of Mechanical Engineering, Colorado State
University, Fort Collins, Colorado 80523, United States
- Department
of Environmental and Radiological Health Sciences, Colorado State University, Fort
Collins, Colorado 80523, United States
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3
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Nazari A, Hong J, Taghizadeh-Hesary F, Taghizadeh-Hesary F. Reducing Virus Transmission from Heating, Ventilation, and Air Conditioning Systems of Urban Subways. TOXICS 2022; 10:796. [PMID: 36548629 PMCID: PMC9784553 DOI: 10.3390/toxics10120796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Aerosols carrying the virus inside enclosed spaces is an important mode of transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as supported by growing evidence. Urban subways are one of the most frequented enclosed spaces. The subway is a utilitarian and low-cost transit system in modern society. However, studies are yet to demonstrate patterns of viral transmission in subway heating, ventilation, and air conditioning (HVAC) systems. To fill this gap, we performed a computational investigation of the airflow (and associated aerosol transmission) in an urban subway cabin equipped with an HVAC system. We employed a transport equation for aerosol concentration, which was added to the basic buoyant solver to resolve the aerosol transmission inside the subway cabin. This was achieved by considering the thermal, turbulent, and induced ventilation flow effects. Using the probability of encountering aerosols on sampling surfaces crossing the passenger breathing zones, we detected the highest infection risk zones inside the urban subway under different settings. We proposed a novel HVAC system that can impede aerosol spread, both vertically and horizontally, inside the cabin. In the conventional model, the maximum probability of encountering aerosols from the breathing of infected individuals near the fresh-air ducts was equal to 51.2%. This decreased to 3.5% in the proposed HVAC model. Overall, using the proposed HVAC system for urban subways led to a decrease in the mean value of the probability of encountering the aerosol by approximately 84% compared with that of the conventional system.
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Affiliation(s)
- Ata Nazari
- Department of Mechanical Engineering, University of Tabriz, Tabriz 51666-16471, Iran
| | - Jiarong Hong
- Mechanical Engineering & Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55455, USA
| | - Farzad Taghizadeh-Hesary
- ENT and Head and Neck Research Center and Department, The Five Sense Health Institute, School of Medicine, Iran University of Medical Sciences, Tehran 14535, Iran
| | - Farhad Taghizadeh-Hesary
- TOKAI Research Institute for Environment and Sustainability (TRIES), Tokai University, Hiratsuka-shi 259-1292, Kanagawa-ken, Japan
- School of Global Studies, Tokai University, Hiratsuka-shi 259-1292, Kanagawa-ken, Japan
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Berghöfer A, Rotter G, Pankert J, Icke K, Roll S, King R, Willich SN. SARS-CoV-2 infections in professional orchestra and choir musicians-a prospective cohort study. Eur J Epidemiol 2022; 37:1061-1070. [PMID: 36173478 PMCID: PMC9519404 DOI: 10.1007/s10654-022-00917-x] [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: 03/18/2022] [Accepted: 09/13/2022] [Indexed: 11/25/2022]
Abstract
During the COVID-19 pandemic, rehearsal and concert activities of professional orchestras and choirs were severely restricted based on the assumption of particularly high infection risks associated with wind instruments and singing. Therefore, our primary objective was to determine the incidence of SARS-CoV-2 infections in orchestra and choir musicians compared to controls. We also assessed influenza, flu, upper respiratory tract infections, and course of illness. Musicians from professional orchestras and choirs and controls from 23 institutions throughout Germany were included in a prospective cohort study. Data were collected from October 2020 to June 2021 by weekly online surveys. A mixed-effects cox proportional hazards model was used to assess the effect of exposure by professional activity on SARS-CoV-2 infection. In 1,097 participants (46.7 years (SD 10.3); 46.8% female; 705 orchestra, 154 choir, and 238 control subjects) 40 SARS-CoV-2 infections occurred. Cases per person-years were 0.06 in orchestras, 0.11 in choirs, and 0.03 in controls. Hazard ratios compared to controls were 1.74 (95% CI 0.58 to 5.25, p = 0.320) for orchestra musicians and 2.97 (0.87 to 10.28, p = 0.087) for choir singers. Infection source was suspected predominantly in private contexts. Disease courses were mild to moderate. Other respiratory infections were reported in 6.1% of study weeks in orchestras, 10.1% in choirs, and 8.0% in controls. Sick leave days of total study days were 0.5, 2.1 and 1.3%, respectively. This epidemiologic study during the pandemic in professional musicians indicates no increased risk of SARS-CoV-2 infections in orchestra musicians and a trend towards increased risk in choir singers compared to controls. However, the exact routes of infection could not be validated. If appropriate hygiene concepts are adhered to, safe orchestra and choir activity appears possible in pandemic times.
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Affiliation(s)
- Anne Berghöfer
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
| | - Gabriele Rotter
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Joachim Pankert
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Katja Icke
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Stephanie Roll
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ryan King
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Stefan N Willich
- Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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5
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Zhang X, Wu J, Smith LM, Li X, Yancey O, Franzblau A, Dvonch JT, Xi C, Neitzel RL. Monitoring SARS-CoV-2 in air and on surfaces and estimating infection risk in buildings and buses on a university campus. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2022; 32:751-758. [PMID: 35477766 PMCID: PMC9045468 DOI: 10.1038/s41370-022-00442-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 05/13/2023]
Abstract
BACKGROUND Evidence is needed on the presence of SARS-CoV-2 in various types of environmental samples and on the estimated transmission risks in non-healthcare settings on campus. OBJECTIVES The objective of this research was to collect data on SARS-CoV-2 viral load and to examine potential infection risks of people exposed to the virus in publicly accessible non-healthcare environments on a university campus. METHODS Air and surface samples were collected using wetted wall cyclone bioaerosol samplers and swab kits, respectively, in a longitudinal environmental surveillance program from August 2020 until April 2021 on the University of Michigan Ann Arbor campus. Quantitative rRT-PCR with primers and probes targeting gene N1 were used for SARS-CoV-2 RNA quantification. The RNA concentrations were used to estimate the probability of infection by quantitative microbial risk assessment modeling and Monte-Carlo simulation. RESULTS In total, 256 air samples and 517 surface samples were collected during the study period, among which positive rates were 1.6% and 1.4%, respectively. Point-biserial correlation showed that the total case number on campus was significantly higher in weeks with positive environmental samples than in non-positive weeks (p = 0.001). The estimated probability of infection was about 1 per 100 exposures to SARS-CoV-2-laden aerosols through inhalation and as high as 1 per 100,000 exposures from contacting contaminated surfaces in simulated scenarios. SIGNIFICANCE Viral shedding was demonstrated by the detection of viral RNA in multiple air and surface samples on a university campus. The low overall positivity rate indicated that the risk of exposure to SARS-CoV-2 at monitored locations was low. Risk modeling results suggest that inhalation is the predominant route of exposure compared to surface contact, which emphasizes the importance of protecting individuals from airborne transmission of SARS-CoV-2 and potentially other respiratory infectious diseases. IMPACT Given the reoccurring epidemics caused by highly infectious respiratory viruses in recent years, our manuscript reinforces the importance of monitoring environmental transmission by the simultaneous sampling and integration of multiple environmental surveillance matrices for modeling and risk assessment.
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Affiliation(s)
- Xin Zhang
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Jianfeng Wu
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Lauren M Smith
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Xin Li
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Olivia Yancey
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Alfred Franzblau
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - J Timothy Dvonch
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Chuanwu Xi
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Richard L Neitzel
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
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6
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Knobling B, Franke G, Beike L, Dickhuth T, Knobloch JK. Reading the Score of the Air-Change in Airborne Microbial Load in Contrast to Particulate Matter during Music Making. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:9939. [PMID: 36011574 PMCID: PMC9408517 DOI: 10.3390/ijerph19169939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
The potential impact of music-making on air quality around musicians was inferred at the outset of the SARS-CoV-2 pandemic from measurements on individual musical instruments and from theoretical considerations. However, it is unclear to what extent playing together in an orchestra under optimal ventilation conditions really increases infection risks for individual musicians. In this study, changes in indoor air quality were assessed by measuring common parameters, i.e., temperature, relative humidity, and carbon dioxide, along with particle counting and determining the presence of airborne pharyngeal bacteria under different seating arrangements. The study was conducted in cooperation with a professional orchestra on a stage ventilated by high volume displacement ventilation. Even with a full line-up, the particle load was only slightly influenced by the presence of the musicians on stage. At the same time, however, a clear increase in pharyngeal flora could be measured in front of individual instrument groups, but independent of seat spacing. Simultaneous measurement of various air parameters and, above all, the determination of relevant indicator bacteria in the air, enables site-specific risk assessment and safe music-making even during a pandemic.
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7
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Aerosol emissions from wind instruments: effects of performer age, sex, sound pressure level, and bell covers. Sci Rep 2022; 12:11303. [PMID: 35788635 PMCID: PMC9252563 DOI: 10.1038/s41598-022-15530-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/24/2022] [Indexed: 12/30/2022] Open
Abstract
Aerosol emissions from wind instruments are a suspected route of transmission for airborne infectious diseases, such as SARS-CoV-2. We evaluated aerosol number emissions (from 0.25 to 35.15 μm) from 81 volunteer performers of both sexes and varied age (12 to 63 years) while playing wind instruments (bassoon, clarinet, flute, French horn, oboe, piccolo, saxophone, trombone, trumpet, and tuba) or singing. Measured emissions spanned more than two orders of magnitude, ranging in rate from < 8 to 1,815 particles s-1, with brass instruments, on average, producing 191% (95% CI 81-367%) more aerosol than woodwinds. Being male was associated with a 70% increase in emissions (vs. female; 95% CI 9-166%). Each 1 dBA increase in sound pressure level was associated with a 28% increase (95% CI 10-40%) in emissions from brass instruments; sound pressure level was not associated with woodwind emissions. Age was not a significant predictor of emissions. The use of bell covers reduced aerosol emissions from three brass instruments tested (trombone, tuba, and trumpet), with average reductions ranging from 53 to 73%, but not for the two woodwind instruments tested (oboe and clarinet). Results from this work can facilitate infectious disease risk management for the performing arts.
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Wang L, Lin T, Da Costa H, Zhu S, Stockman T, Kumar A, Weaver J, Spede M, Milton DK, Hertzberg J, Toohey DW, Vance ME, Miller SL, Srebric J. Characterization of aerosol plumes from singing and playing wind instruments associated with the risk of airborne virus transmission. INDOOR AIR 2022; 32:e13064. [PMID: 35762243 PMCID: PMC9328346 DOI: 10.1111/ina.13064] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/25/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The exhalation of aerosols during musical performances or rehearsals posed a risk of airborne virus transmission in the COVID-19 pandemic. Previous research studied aerosol plumes by only focusing on one risk factor, either the source strength or convective transport capability. Furthermore, the source strength was characterized by the aerosol concentration and ignored the airflow rate needed for risk analysis in actual musical performances. This study characterizes aerosol plumes that account for both the source strength and convective transport capability by conducting experiments with 18 human subjects. The source strength was characterized by the source aerosol emission rate, defined as the source aerosol concentration multiplied by the source airflow rate (brass 383 particle/s, singing 408 particle/s, and woodwind 480 particle/s). The convective transport capability was characterized by the plume influence distance, defined as the sum of the horizontal jet length and horizontal instrument length (brass 0.6 m, singing 0.6 m and woodwind 0.8 m). Results indicate that woodwind instruments produced the highest risk with approximately 20% higher source aerosol emission rates and 30% higher plume influence distances compared with the average of the same risk indicators for singing and brass instruments. Interestingly, the clarinet performance produced moderate source aerosol concentrations at the instrument's bell, but had the highest source aerosol emission rates due to high source airflow rates. Flute performance generated plumes with the lowest source aerosol emission rates but the highest plume influence distances due to the highest source airflow rate. Notably, these comprehensive results show that the source airflow is a critical component of the risk of airborne disease transmission. The effectiveness of masking and bell covering in reducing aerosol transmission is due to the mitigation of both source aerosol concentrations and plume influence distances. This study also found a musician who generated approximately five times more source aerosol concentrations than those of the other musicians who played the same instrument. Despite voice and brass instruments producing measurably lower average risk, it is possible to have an individual musician produce aerosol plumes with high source strength, resulting in enhanced transmission risk; however, our sample size was too small to make generalizable conclusions regarding the broad musician population.
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Affiliation(s)
- Lingzhe Wang
- Department of Mechanical EngineeringUniversity of MarylandCollege ParkMarylandUSA
| | - Tong Lin
- Department of Mechanical EngineeringUniversity of MarylandCollege ParkMarylandUSA
| | - Hevander Da Costa
- Department of Mechanical EngineeringUniversity of MarylandCollege ParkMarylandUSA
| | - Shengwei Zhu
- Department of Mechanical EngineeringUniversity of MarylandCollege ParkMarylandUSA
| | - Tehya Stockman
- Department of Civil, Environmental, and Architectural EngineeringUniversity of Colorado BoulderBoulderColoradoUSA
| | - Abhishek Kumar
- Department of Mechanical EngineeringUniversity of Colorado BoulderBoulderColoradoUSA
| | - James Weaver
- National Federation of State High School AssociationsIndianapolisIndianaUSA
| | - Mark Spede
- Department of Performing ArtsClemson UniversityClemsonSouth CarolinaUSA
| | - Donald K. Milton
- Maryland Institute for Applied Environmental Health, School of Public HealthUniversity of MarylandCollege ParkMarylandUSA
| | - Jean Hertzberg
- Department of Mechanical EngineeringUniversity of Colorado BoulderBoulderColoradoUSA
| | - Darin W. Toohey
- Department of Atmospheric and Oceanic SciencesUniversity of Colorado BoulderBoulderColoradoUSA
| | - Marina E. Vance
- Department of Mechanical EngineeringUniversity of Colorado BoulderBoulderColoradoUSA
| | - Shelly L. Miller
- Department of Mechanical EngineeringUniversity of Colorado BoulderBoulderColoradoUSA
| | - Jelena Srebric
- Department of Mechanical EngineeringUniversity of MarylandCollege ParkMarylandUSA
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9
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Firle C, Steinmetz A, Stier O, Stengel D, Ekkernkamp A. Aerosol emission from playing wind instruments and related COVID-19 infection risk during music performance. Sci Rep 2022; 12:8598. [PMID: 35597808 PMCID: PMC9124212 DOI: 10.1038/s41598-022-12529-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 04/29/2022] [Indexed: 12/29/2022] Open
Abstract
The pandemic of COVID-19 led to restrictions in all kinds of music activities. Airborne transmission of SARS-CoV-2 requires risk assessment of wind instrument playing in various situations. Previous studies focused on short-range transmission, whereas long-range transmission risk has not been assessed. The latter requires knowledge of aerosol emission rates from wind instrument playing. We measured aerosol concentrations in a hermetically closed chamber of 20 m3 in an operating theatre as resulting from 20 min standardized wind instrument playing (19 flute, 11 oboe, 1 clarinet, 1 trumpet players). We calculated aerosol emission rates showing uniform distribution for both instrument groups. Aerosol emission from wind instrument playing ranged from 11 ± 288 particles/second (P/s) up to 2535 ± 195 P/s, expectation value ± uncertainty standard deviation. The analysis of aerosol particle size distributions shows that 70–80% of emitted particles had a size of 0.25–0.8 µm and thus are alveolar. Masking the bell with a surgical mask did not reduce aerosol emission. Aerosol emission rates were higher from wind instrument playing than from speaking or breathing. Differences between instrumental groups could not be found but high interindividual variance, as expressed by uniform distribution of aerosol emission rates. Our findings indicate that aerosol emission depends on physiological factors and playing techniques rather than on the type of instrument, in contrast to some previous studies. Based on our results, we present transmission risk calculations for long-range transmission of COVID-19 for three typical woodwind playing situations.
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Affiliation(s)
- Carl Firle
- GP Practice, Dr. Claudia-Isabella Wildfeuer, 10715, Berlin, Germany.
| | - Anke Steinmetz
- Physical and Rehabilitation Medicine, Department of Trauma, Reconstructive Surgery and Rehabilitation Medicine, University Medicine Greifswald, Greifswald, Germany
| | | | - Dirk Stengel
- BG Kliniken-Klinikverbund Der Gesetzlichen Unfallversicherung gGmbH, Berlin, Germany.,BG Klinikum Unfallkrankenhaus Berlin gGmbH, Berlin, Germany
| | - Axel Ekkernkamp
- Physical and Rehabilitation Medicine, Department of Trauma, Reconstructive Surgery and Rehabilitation Medicine, University Medicine Greifswald, Greifswald, Germany.,Department of Trauma, Reconstructive Surgery, and Rehabilitation Medicine, University Medicine Greifswald, Greifswald, Germany.,BG Klinikum Unfallkrankenhaus Berlin gGmbH, Berlin, Germany
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10
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Gantner S, Echternach M, Veltrup R, Westphalen C, Köberlein MC, Kuranova L, Peters G, Jakubaß B, Benthaus T, Döllinger M, Kniesburges S. Impulse dispersion of aerosols during playing wind instruments. PLoS One 2022; 17:e0262994. [PMID: 35239657 PMCID: PMC8893631 DOI: 10.1371/journal.pone.0262994] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 01/10/2022] [Indexed: 12/24/2022] Open
Abstract
Musical activities, especially singing and playing wind instruments, have been singled out as potentially high-risk activities for the transmission of SARS CoV-2, due to a higher rate of aerosol production and emission. Playing wind instruments can produce condensation, droplets of saliva, and aerosol particles, which hover and spread in the environmental air's convectional flows and which can be potentially infectious. The aim of this study is to investigate the primary impulse dispersion of aerosols that takes place during the playing of different wind instruments as compared to breathing and to speaking. Nine professional musicians (3 trumpeters, 3 flautists and 3 clarinetists) from the Bavarian Symphony Orchestra performed the main theme from the 4th movement of Ludwig van Beethoven's 9th symphony in different pitches and loudness. The inhaled air volume was marked with small aerosol particles produced using a commercial e-cigarette. The expelled aerosol cloud was recorded by cameras from different perspectives. Afterwards, the dimensions and dynamics of the aerosol cloud were measured by segmenting the video footage at every time point. Overall, the flutes produced the largest dispersion at the end of the task, reaching maximum forward distances of 1.88 m. An expulsion of aerosol was observed in different directions: upwards and downwards at the mouthpiece, at the end of the instrument, and along the flute at the key plane. In comparison, the maximum impulse dispersions generated by the trumpets and clarinets were lower in frontal and lateral direction (1.2 m and 1.0 m towards the front, respectively). Also, the expulsion to the sides was lower.
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Affiliation(s)
- Sophia Gantner
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Matthias Echternach
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Reinhard Veltrup
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Erlangen, Medical School, Friedrich-Alexander-University Erlangen-Nueremberg, Erlangen, Germany
| | - Caroline Westphalen
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Marie Christine Köberlein
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Liudmila Kuranova
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, University Hospital, LMU Munich, Munich, Germany
| | - Gregor Peters
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Erlangen, Medical School, Friedrich-Alexander-University Erlangen-Nueremberg, Erlangen, Germany
| | - Bernhard Jakubaß
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Erlangen, Medical School, Friedrich-Alexander-University Erlangen-Nueremberg, Erlangen, Germany
| | - Tobias Benthaus
- Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Michael Döllinger
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Erlangen, Medical School, Friedrich-Alexander-University Erlangen-Nueremberg, Erlangen, Germany
| | - Stefan Kniesburges
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head & Neck Surgery, University Hospital Erlangen, Medical School, Friedrich-Alexander-University Erlangen-Nueremberg, Erlangen, Germany
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11
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Charvet A, Bardin-Monnier N, Thomas D, Dufaud O, Pfrimmer M, Barrault M, Bourrous S, Mocho V, Ouf FX, Poirier S, Jeanmichel L, Segovia C, Ferry D, Grauby O. Impact of washing cycles on the performances of face masks. JOURNAL OF AEROSOL SCIENCE 2022; 160:105914. [PMID: 36530797 PMCID: PMC9749850 DOI: 10.1016/j.jaerosci.2021.105914] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 06/15/2023]
Abstract
The tension on the supply of surgical and FFP2 masks during the first wave of the COVID-19 pandemic leads to study the potential reuse of these masks. As washing is easily adaptable at home, this treatment solution was retained. In this work, thirty-six references of surgical masks and four FFP2 masks were tested without being worn or washed and after several washing cycles. The results highlighted a great heterogeneity of performances depending on the mask trademarks, both for surgical masks and FFP2. The quality of the meltblown and spunbond layers and the presence/absence of electrostatic charges at the fiber surface are put forward to explain the variability of results, both on differential pressures and filtration efficiencies. The differential pressure and the particle filtration efficiency of the washed masks were maintained up to 10 washing cycles and met the standard requirements. However, an immersion in water with a detergent induces an efficiency decrease for submicronic particles. This lower performance, constant after the first washing cycle, can be explained by the loss of electrostatic charges during the washing cycle. The modifications of surface properties after washing also lead to a loss of the hydrophobic behavior of type IIR surgical masks, which can therefore no more be considered as resistant to blood projections.
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Affiliation(s)
| | | | | | - Olivier Dufaud
- Université de Lorraine, CNRS, LRGP, F-54000, Nancy, France
| | | | - Mathieu Barrault
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SCA, Gif-Sur-Yvette, 91192, France
| | - Soleiman Bourrous
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SCA, Gif-Sur-Yvette, 91192, France
| | - Victor Mocho
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SCA, Gif-Sur-Yvette, 91192, France
| | - François-Xavier Ouf
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SCA, Gif-Sur-Yvette, 91192, France
| | - Stéphane Poirier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SCA, Gif-Sur-Yvette, 91192, France
| | | | - César Segovia
- CETELOR, Université de Lorraine, F-88000, Épinal, France
| | - Daniel Ferry
- Aix-Marseille Univ, CNRS, CINaM, F-13009, Marseille, France
| | - Olivier Grauby
- Aix-Marseille Univ, CNRS, CINaM, F-13009, Marseille, France
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12
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Stockman T, Zhu S, Kumar A, Wang L, Patel S, Weaver J, Spede M, Milton DK, Hertzberg J, Toohey D, Vance M, Srebric J, Miller SL. Measurements and Simulations of Aerosol Released while Singing and Playing Wind Instruments. ACS ENVIRONMENTAL AU 2021; 1:71-84. [PMID: 37155479 PMCID: PMC8525345 DOI: 10.1021/acsenvironau.1c00007] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Outbreaks from choir performances, such as the Skagit Valley Choir, showed that singing brings potential risk of COVID-19 infection. There is less known about the risks of airborne infection from other musical performances, such as playing wind instruments or performing theater. In addition, it is important to understand methods that can be used to reduce infection risk. In this study, we used a variety of methods, including flow visualization, aerosol and CO2 measurements, and computational fluid dynamics (CFD) modeling to understand the different components that can lead to transmission risk from musical performance and risk mitigation. This study was possible because of a partnership across academic departments and institutions and collaboration with the National Federation of State High School Associations and the College Band Directors National Association. The interdisciplinary team enabled us to understand the various aspects of aerosol transmission risk from musical performance and to quickly implement strategies in music classrooms during the COVID-19 pandemic. We found that plumes from musical performance were highly directional, unsteady and varied considerably in time and space. Aerosol number concentration measured at the bell of the clarinet was comparable to that of singing. Face and bell masks attenuated plume velocities and lengths and decreased aerosol concentrations measured in front of the masks. CFD modeling showed differences between indoor and outdoor environments and that the lowest risk of airborne COVID-19 infection occurred at less than 30 min of exposure indoors and less than 60 min outdoors.
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Affiliation(s)
- Tehya Stockman
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Shengwei Zhu
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Abhishek Kumar
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Lingzhe Wang
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Sameer Patel
- Department of Civil Engineering, Indian Institute of Technology, Gandhinagar, Gujrat 382355, India
| | - James Weaver
- National Federation of State High School Associations, Indianapolis, Indiana 46402, United States
| | - Mark Spede
- Department of Performing Arts, Clemson University, Clemson, South Carolina 29634, United States
| | - Donald K. Milton
- Maryland Institute for Applied Environmental Health, School of Public Health, University of Maryland, College Park, Maryland 20740, United States
| | - Jean Hertzberg
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Darin Toohey
- Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Marina Vance
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jelena Srebric
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Shelly L. Miller
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
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13
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Locke L, Dada O, Shedd JS. Aerosol Transmission of Infectious Disease and the Efficacy of Personal Protective Equipment (PPE): A Systematic Review. J Occup Environ Med 2021; 63:e783-e791. [PMID: 34419986 PMCID: PMC8562920 DOI: 10.1097/jom.0000000000002366] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Health care professionals and governmental agencies are in consensus regarding contact and droplet transmission of infectious diseases. However, personal protective equipment (PPE) efficacy is not considered for aerosol or airborne transmission of infectious diseases. This review discusses the inhalation of virus-laden aerosols as a viable mechanism of transmission of various respiratory infectious diseases and PPE efficacy. METHODS The Preferred Reporting Items for Systematic reviews, and Meta-Analysis (PRISMA) guidelines was used. RESULTS The transmission of infectious disease is of concern for all respirable diseases discussed (SARS-CoV-1, SARS-CoV-2, MERS, influenza, and tuberculosis), and the effectiveness of facemasks is dependent on the efficiency of the filter, fit, and proper use. CONCLUSION PPE should be the last resort in preventing the spread of infectious disease and should only be used for protection and not to control the transmission.
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Affiliation(s)
- Laramie Locke
- Department of Occupational Safety and Health, Murray State University, Kentucky (Mr Locke, Dr Dada); Eastman Chemical Company, Tennessee (Mr Locke); and Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, Alabama (Mr Shedd)
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14
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Hedworth HA, Karam M, McConnell J, Sutherland JC, Saad T. Mitigation strategies for airborne disease transmission in orchestras using computational fluid dynamics. SCIENCE ADVANCES 2021; 7:eabg4511. [PMID: 34162550 PMCID: PMC8221623 DOI: 10.1126/sciadv.abg4511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/07/2021] [Indexed: 06/09/2023]
Abstract
The COVID-19 pandemic forced performing arts groups to cancel shows and entire seasons due to safety concerns for the audience and performers. It is unclear to what extent aerosols generated by wind instruments contribute to exposure because their fate is dependent on the airflow onstage. We use transient, second-order accurate computational fluid dynamics (CFD) simulations and quantitative microbial risk assessment to estimate aerosol concentrations and the associated risk and assess strategies to mitigate exposure in two distinct concert venues. Mitigation strategies involved rearranging musicians and altering the airflow by changing HVAC settings, opening doors, and introducing flow-directing geometries. Our results indicate that the proposed mitigation strategies can reduce aerosol concentrations in the breathing zone by a factor of 100, corresponding to a similar decrease in the probability of infection.
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Affiliation(s)
- Hayden A Hedworth
- Department of Chemical Engineering, University of Utah Salt Lake City, UT 84112, USA
| | - Mokbel Karam
- Department of Chemical Engineering, University of Utah Salt Lake City, UT 84112, USA
| | - Josh McConnell
- Department of Chemical Engineering, University of Utah Salt Lake City, UT 84112, USA
| | - James C Sutherland
- Department of Chemical Engineering, University of Utah Salt Lake City, UT 84112, USA
| | - Tony Saad
- Department of Chemical Engineering, University of Utah Salt Lake City, UT 84112, USA.
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15
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Taylor H, Wall W, Ross D, Janarthanan R, Wang L, Aiano F, Ellis J, Gopal R, Andrews N, Patel M, Lackenby A, Myers R, Ramsay ME, Chow JY, Zambon M, Ladhani SN. Cross sectional investigation of a COVID-19 outbreak at a London Army barracks: Neutralising antibodies and virus isolation. THE LANCET REGIONAL HEALTH. EUROPE 2021; 2:100015. [PMID: 33870245 PMCID: PMC7834392 DOI: 10.1016/j.lanepe.2020.100015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Military personnel in enclosed societies are at increased risk of respiratory infections. We investigated an outbreak of Coronavirus Disease 2019 in a London Army barracks early in the pandemic. METHODS Army personnel, their families and civilians had nasal and throat swabs for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by reverse transcriptase -polymerase chain reaction (RT-PCR), virus isolation and whole genome sequencing, along with blood samples for SARS-CoV-2 antibodies. All tests were repeated 36 days later. FINDINGS During the first visit, 304 (254 Army personnel, 10 family members, 36 civilians, 4 not stated) participated and 24/304 (8%) were SARS-CoV-2 RT-PCR positive. Infectious virus was isolated from 7/24 (29%). Of the 285 who provided a blood sample, 7% (19/285) were antibody positive and 63% (12/19) had neutralising antibodies. Twenty-two (22/34, 64%) individuals with laboratory-confirmed infection were asymptomatic. Nine SARS-CoV-2 RT-PCR positive participants were also antibody positive but those who had neutralising antibodies did not have infectious virus. At the second visit, no new infections were detected, and 13% (25/193) were seropositive, including 52% (13/25) with neutralising antibodies. Risk factors for SARS-CoV-2 antibody positivity included contact with a confirmed case (RR 25.2; 95% CI 14-45), being female (RR 2.5; 95% CI 1.0-6.0) and two-person shared bathroom (RR 2.6; 95% CI 1.1-6.4). INTERPRETATION We identified high rates of asymptomatic SARS-CoV-2 infection. Public Health control measures can mitigate spread but virus re-introduction from asymptomatic individuals remains a risk. Most seropositive individuals had neutralising antibodies and infectious virus was not recovered from anyone with neutralising antibodies. FUNDING PHE.
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Affiliation(s)
- Hannah Taylor
- Immunisation and Countermeasures Division, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
- Army Medical Services, Robertson House, Camberley, GU15 4NP, UK
| | - William Wall
- Army Medical Services, Robertson House, Camberley, GU15 4NP, UK
| | - David Ross
- Army Medical Services, Robertson House, Camberley, GU15 4NP, UK
| | | | - Liyang Wang
- London Health Protection Team, Public Health England, London, UK
| | - Felicity Aiano
- Immunisation and Countermeasures Division, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Joanna Ellis
- Virus Reference Department, Public Health England, London, UK
| | - Robin Gopal
- Virus Reference Department, Public Health England, London, UK
| | - Nick Andrews
- Infectious Disease Informatics, Public Health England, London, UK
| | - Monika Patel
- Virus Reference Department, Public Health England, London, UK
| | - Angie Lackenby
- Virus Reference Department, Public Health England, London, UK
| | - Richard Myers
- Infectious Disease Informatics, Public Health England, London, UK
| | - Mary E Ramsay
- Immunisation and Countermeasures Division, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
| | - J. Yimmy Chow
- London Health Protection Team, Public Health England, London, UK
| | - Maria Zambon
- Virus Reference Department, Public Health England, London, UK
| | - Shamez N Ladhani
- Immunisation and Countermeasures Division, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK
- Paediatric Infectious Diseases Research Group, St. George's University of London, Cranmer Terrace, London SW17 0RE, UK
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16
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Burgmann S, Janoske U. Transmission and reduction of aerosols in classrooms using air purifier systems. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:033321. [PMID: 33897240 PMCID: PMC8060972 DOI: 10.1063/5.0044046] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/24/2021] [Indexed: 05/04/2023]
Abstract
SARS-CoV-2 (COVID-19) as an airborne respiratory disease led to a bunch of open questions: how teaching in classrooms is possible and how the risk of infection can be reduced, e.g., by the use of air purifier systems. In this study, the transmission of aerosols in a classroom is analyzed numerically and experimentally. The aerosol concentration in a classroom equipped with an air purifier system was measured with an aerosol spectrometer (optical particle sizer, TSI Incorporated) at different locations. The transient reduction of the aerosol concentration, which was artificially generated by an aerosol generator (di-ethyl hexyl sebacate-atomizer, detected particle size ranging from 0.3 to 10 μm), was monitored. The experimental results were used to validate a numerical simulation model of the classroom using the Open Source Computational Fluid Dynamics code OpenFOAM® (version 6). With the numerical simulation model, different scenarios with infected persons in the room have been analyzed, showing that the air purifier system leads to a significant reduction of airborne particles in the room dependent on the location of the infected person. The system can support additional ventilation strategies with fresh air, especially in cold seasons.
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Affiliation(s)
| | - Uwe Janoske
- Author to whom correspondence should be addressed:. URL:www.lsm.uni-wuppertal.de
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17
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Narayanan SR, Yang S. Airborne transmission of virus-laden aerosols inside a music classroom: Effects of portable purifiers and aerosol injection rates. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:033307. [PMID: 33746493 PMCID: PMC7978150 DOI: 10.1063/5.0042474] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 01/18/2021] [Indexed: 05/04/2023]
Abstract
The ongoing COVID-19 pandemic has shifted attention to the airborne transmission of exhaled droplet nuclei within indoor environments. The spread of aerosols through singing and musical instruments in music performances has necessitated precautionary methods such as masks and portable purifiers. This study investigates the effects of placing portable air purifiers at different locations inside a classroom and the effects of different aerosol injection rates (e.g., with and without masks, different musical instruments, and different injection modes). Aerosol deposition, airborne concentration, and removal are analyzed in this study. It was found that using purifiers could help in achieving ventilation rates close to the prescribed values by the World Health Organization, while also achieving aerosol removal times within the Center of Disease Control and Prevention recommended guidelines. This could help in deciding break periods between classroom sessions, which was around 25 min through this study. Moreover, proper placement of purifiers could offer significant advantages in reducing airborne aerosol numbers (offering several orders of magnitude higher aerosol removal when compared to nearly zero removal when having no purifiers), and improper placement of the purifiers could worsen the situation. This study suggests the purifier to be placed close to the injector to yield a benefit and away from the people to be protected. The injection rate was found to have an almost linear correlation with the average airborne aerosol suspension rate and deposition rate, which could be used to predict the trends for scenarios with other injection rates.
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Affiliation(s)
- Sai Ranjeet Narayanan
- Department of Mechanical Engineering, University of Minnesota–Twin
Cities, Minneapolis, Minnesota 55455, USA
| | - Suo Yang
- Department of Mechanical Engineering, University of Minnesota–Twin
Cities, Minneapolis, Minnesota 55455, USA
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18
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Mahjoub Mohammed Merghani K, Sagot B, Gehin E, Da G, Motzkus C. A review on the applied techniques of exhaled airflow and droplets characterization. INDOOR AIR 2021; 31:7-25. [PMID: 33206424 PMCID: PMC7753802 DOI: 10.1111/ina.12770] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 10/12/2020] [Accepted: 11/01/2020] [Indexed: 05/18/2023]
Abstract
In the last two decades, multidisciplinary research teams worked on developing a comprehensive understanding of the transmission mechanisms of airborne diseases. This article reviews the experimental studies on the characterization of the exhaled airflow and the droplets, comparing the measured parameters, the advantages, and the limitations of each technique. To characterize the airflow field, the global flow-field techniques-high-speed photography, schlieren photography, and PIV-are applied to visualize the shape and propagation of the exhaled airflow and its interaction with the ambient air, while the pointwise measurements provide quantitative measurements of the velocity, flow rate, humidity and temperature at a single point in the flow field. For the exhaled droplets, intrusive techniques are used to characterize the size distribution and concentration of the droplets' dry residues while non-intrusive techniques can measure the droplet size and velocity at different locations in the flow field. The evolution of droplets' size and velocity away from the source has not yet been thoroughly experimentally investigated. Besides, there is a lack of information about the temperature and humidity fields composed by the interaction of the exhaled airflow and the ambient air.
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