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Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes. Proc Natl Acad Sci U S A 2022; 119:e2203086119. [PMID: 35727979 PMCID: PMC9245670 DOI: 10.1073/pnas.2203086119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Respiratory droplets are widely recognized as the primary vehicle in viral respiratory disease transmission. Accurate information on their number and size distributions is important for appropriate mitigation strategies, for quantitative modeling of airborne disease transmission, and for evaluating the relative importance of droplets originating from saliva versus airway lining fluid. A straightforward experimental setup using inexpensive, readily available components is developed for simultaneous characterization of larger particles by video analysis of laser light scattering and monitoring of smaller sizes by an optical particle counter. Measurements indicate that in a healthy volunteer, the airborne mass of speech aerosol far exceeds that generated by breathing, even when accounting for faster sedimentation of the larger particles. Accurate measurements of the size and quantity of aerosols generated by various human activities in different environments are required for efficacious mitigation strategies and accurate modeling of respiratory disease transmission. Previous studies of speech droplets, using standard aerosol instrumentation, reported very few particles larger than 5 μm. This starkly contrasts with the abundance of such particles seen in both historical slide deposition measurements and more recent light scattering observations. We have reconciled this discrepancy by developing an alternative experimental approach that addresses complications arising from nucleated condensation. Measurements reveal that a large volume fraction of speech-generated aerosol has diameters in the 5- to 20-μm range, making them sufficiently small to remain airborne for minutes, not hours. This coarse aerosol is too large to penetrate the lower respiratory tract directly, and its relevance to disease transmission is consistent with the vast majority of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections initiating in the upper respiratory tract. Our measurements suggest that in the absence of symptoms such as coughing or sneezing, the importance of speech-generated aerosol in the transmission of respiratory diseases is far greater than generally recognized.
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Li W, Chong A, Lasternas B, Peck TG, Tham KW. Quantifying the effectiveness of desk dividers in reducing droplet and airborne virus transmission. INDOOR AIR 2022; 32:e12950. [PMID: 34704624 PMCID: PMC8653303 DOI: 10.1111/ina.12950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/21/2021] [Accepted: 10/13/2021] [Indexed: 05/30/2023]
Abstract
The utilization of physical dividers has been recommended as a practical approach to reducing the droplet and aerosol transmissions of the COVID-19 virus (SARS-CoV-2). This study conducted a series of experiments using video recording with a high-speed camera, particle image velocimetry (PIV) technique, and concentration measurements. The effectiveness of Perspex desk dividers impeding the transient transmission during coughing in five representative layouts was investigated. The results showed that the divider effectively protected the exposed person from an infector's cough seated in a face-to-face arrangement at a distance of 1.5 m. The aerosol concentration at the breathing zone was reduced by 99% compared to the layout without dividers. However, the reflection of aerosols from the dividers increased the exposure risk to the person seated beside the infector. Such risk was substantially reduced if the dividers were placed parallel between the infector and exposed person seated side-by-side. When the exposed person was staggered (face-to-face but displaced sideways laterally) to the infector with a 0.55-m lateral distance, the dividers reduced the potential exposure at the breathing zone by 60%. Considering the effectiveness in exposure reduction, the staggered configuration of desk dividers between the infector and exposed persons offers the best reduction to exposure.
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Affiliation(s)
- Wenxin Li
- Department of the Built EnvironmentSchool of Design and EnvironmentNational University of SingaporeSingapore117566Singapore
| | - Adrian Chong
- Department of the Built EnvironmentSchool of Design and EnvironmentNational University of SingaporeSingapore117566Singapore
| | - Bertrand Lasternas
- Department of the Built EnvironmentSchool of Design and EnvironmentNational University of SingaporeSingapore117566Singapore
| | - Thian Guan Peck
- Office of Safety, Health and EnvironmentNational University of SingaporeSingapore119246Singapore
| | - Kwok Wai Tham
- Department of the Built EnvironmentSchool of Design and EnvironmentNational University of SingaporeSingapore117566Singapore
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Hofstätter N, Hofer S, Duschl A, Himly M. Children's Privilege in COVID-19: The Protective Role of the Juvenile Lung Morphometry and Ventilatory Pattern on Airborne SARS-CoV-2 Transmission to Respiratory Epithelial Barriers and Disease Severity. Biomedicines 2021; 9:1414. [PMID: 34680531 PMCID: PMC8533273 DOI: 10.3390/biomedicines9101414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/01/2021] [Accepted: 10/06/2021] [Indexed: 11/17/2022] Open
Abstract
The incidence of severe COVID-19 in children is low, and underlying mechanisms for lower SARS-CoV-2 susceptibility and self-limiting disease severity are poorly understood. Severe clinical manifestations in adults require SARS-CoV-2 inoculation in the lower respiratory tract, establishing a pulmonary disease phase. This may be either accomplished by direct inoculation of the thoracic region upon exposure to virion-laden aerosols, or by infection of the upper respiratory system and aspiration of virion-laden aerosols originating right there into the lower respiratory tract. The particularities of epithelial barriers as the anatomical site of first viral deposition specifically determine the initial characteristics of an innate immune response, emerging respiratory tissue damage and dysfunctionality, and hence, severity of clinical symptoms. We, thus, investigated by in silico modeling whether the combined effect of juvenile lung morphometry, children's ventilatory pattern and the peculiarities of the virion-laden aerosols' properties, render children more resilient to aerosol deposition in the lower respiratory tract. Our study presents evidence for major age-dependent differences of the regional virion-laden aerosol deposition. We identified deposition hotspots in the alveolar-interstitial region of the young adult. Our data reveal that children are void of corresponding hotspots. The inoculum quantum in the alveolar-interstitial region hotspots is found to be considerably related to age. Our results suggest that children are intrinsically protected against SARS-CoV-2 inoculation in the lower respiratory tract, which may help to explain the lower risk of severe clinical manifestations associated with a pulmonary phase.
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Affiliation(s)
| | | | | | - Martin Himly
- Department of Biosciences, Paris Lodron University of Salzburg (PLUS), 5020 Salzburg, Austria; (N.H.); (S.H.); (A.D.)
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Hofer S, Hofstätter N, Duschl A, Himly M. SARS-CoV-2-Laden Respiratory Aerosol Deposition in the Lung Alveolar-Interstitial Region Is a Potential Risk Factor for Severe Disease: A Modeling Study. J Pers Med 2021; 11:431. [PMID: 34069409 PMCID: PMC8159114 DOI: 10.3390/jpm11050431] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/10/2021] [Accepted: 05/17/2021] [Indexed: 12/23/2022] Open
Abstract
COVID-19, predominantly a mild disease, is associated with more severe clinical manifestation upon pulmonary involvement. Virion-laden aerosols and droplets target different anatomical sites for deposition. Compared to droplets, aerosols more readily advance into the peripheral lung. We performed in silico modeling to confirm the secondary pulmonary lobules as the primary site of disease initiation. By taking different anatomical aerosol origins into consideration and reflecting aerosols from exhalation maneuvers breathing and vocalization, the physicochemical properties of generated respiratory aerosol particles were defined upon conversion to droplet nuclei by evaporation at ambient air. To provide detailed, spatially-resolved information on particle deposition in the thoracic region of the lung, a top-down refinement approach was employed. Our study presents evidence for hot spots of aerosol deposition in lung generations beyond the terminal bronchiole, with a maximum in the secondary pulmonary lobules and a high preference to the lower lobes of both lungs. In vivo, initial chest CT anomalies, the ground glass opacities, resulting from partial alveolar filling and interstitial thickening in the secondary pulmonary lobules, are likewise localized in these lung generations, with the highest frequency in both lower lobes and in the early stage of disease. Hence, our results suggest a disease initiation right there upon inhalation of virion-laden respiratory aerosols, linking the aerosol transmission route to pathogenesis associated with higher disease burden and identifying aerosol transmission as a new independent risk factor for developing a pulmonary phase with a severe outcome.
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Affiliation(s)
| | | | | | - Martin Himly
- Department of Biosciences, Paris Lodron University of Salzburg (PLUS), 5020 Salzburg, Austria; (S.H.); (N.H.); (A.D.)
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Blocken B, van Druenen T, Ricci A, Kang L, van Hooff T, Qin P, Xia L, Ruiz CA, Arts JH, Diepens JFL, Maas GA, Gillmeier SG, Vos SB, Brombacher AC. Ventilation and air cleaning to limit aerosol particle concentrations in a gym during the COVID-19 pandemic. BUILDING AND ENVIRONMENT 2021; 193:107659. [PMID: 33568882 PMCID: PMC7860965 DOI: 10.1016/j.buildenv.2021.107659] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 01/28/2021] [Accepted: 01/31/2021] [Indexed: 05/03/2023]
Abstract
SARS-CoV-2 can spread by close contact through large droplet spray and indirect contact via contaminated objects. There is mounting evidence that it can also be transmitted by inhalation of infected saliva aerosol particles. These particles are generated when breathing, talking, laughing, coughing or sneezing. It can be assumed that aerosol particle concentrations should be kept low in order to minimize the potential risk of airborne virus transmission. This paper presents measurements of aerosol particle concentrations in a gym, where saliva aerosol production is pronounced. 35 test persons performed physical exercise and aerosol particle concentrations, CO2 concentrations, air temperature and relative humidity were obtained in the room of 886 m³. A separate test was used to discriminate between human endogenous and exogenous aerosol particles. Aerosol particle removal by mechanical ventilation and mobile air cleaning units was measured. The gym test showed that ventilation with air-change rate ACH = 2.2 h-1, i.e. 4.5 times the minimum of the Dutch Building Code, was insufficient to stop the significant aerosol concentration rise over 30 min. Air cleaning alone with ACH = 1.39 h-1 had a similar effect as ventilation alone. Simplified mathematical models were engaged to provide further insight into ventilation, air cleaning and deposition. It was shown that combining the above-mentioned ventilation and air cleaning can reduce aerosol particle concentrations with 80 to 90% , depending on aerosol size. This combination of existing ventilation supplemented with air cleaning is energy efficient and can also be applied for other indoor environments.
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Affiliation(s)
- B Blocken
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
- Building Physics and Sustainable Design, Department of Civil Engineering, KU Leuven, Kasteelpark Arenberg 40 - Bus 2447, 3001, Leuven, Belgium
| | - T van Druenen
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - A Ricci
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
- Building Physics and Sustainable Design, Department of Civil Engineering, KU Leuven, Kasteelpark Arenberg 40 - Bus 2447, 3001, Leuven, Belgium
- Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
| | - L Kang
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - T van Hooff
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - P Qin
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - L Xia
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - C Alanis Ruiz
- Building Physics and Sustainable Design, Department of Civil Engineering, KU Leuven, Kasteelpark Arenberg 40 - Bus 2447, 3001, Leuven, Belgium
| | - J H Arts
- Department of Industrial Design, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
- School of Sport Studies, Fontys University of Applied Sciences, Theo Koomenlaan 3, 5644HZ Eindhoven, the Netherlands
| | - J F L Diepens
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - G A Maas
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - S G Gillmeier
- Unit Building Physics and Services, Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
| | - S B Vos
- Department of Industrial Design, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
- School of Sport Studies, Fontys University of Applied Sciences, Theo Koomenlaan 3, 5644HZ Eindhoven, the Netherlands
| | - A C Brombacher
- Department of Industrial Design, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, the Netherlands
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Riediker M, Tsai DH. Estimation of Viral Aerosol Emissions From Simulated Individuals With Asymptomatic to Moderate Coronavirus Disease 2019. JAMA Netw Open 2020; 3:e2013807. [PMID: 32716517 DOI: 10.1001/jamanetworkopen.2020.13807] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
IMPORTANCE Individuals with asymptomatic or mild coronavirus disease 2019 (COVID-19) have been reported to frequently transmit the disease even without direct contact. The severe acute respiratory syndrome coronavirus 2 has been found at very high concentrations in swab and sputum samples from such individuals. OBJECTIVE To estimate the virus levels released from individuals with asymptomatic to moderate COVID-19 into different aerosol sizes by normal breathing and coughing, and to determine what exposure could result from this in a room shared with such individuals. DESIGN, SETTING, AND PARTICIPANTS This mathematical modeling study combined the size-distribution of exhaled breath microdroplets for coughing and normal breathing with viral swab and sputum concentrations as approximation for lung lining liquid to obtain an estimate of emitted virus levels. Viral data were obtained from studies published as of May 20, 2020. The resulting emission data fed a single-compartment model of airborne concentrations in a room of 50 m3, the size of a small office or medical examination room. MAIN OUTCOMES AND MEASURES Modeling was used to estimate the viral load emitted by individuals breathing normally or coughing, and the concentrations expected in the simulated room at different ventilation rates. RESULTS The mean estimated viral load in microdroplets emitted by simulated individuals while breathing regularly was 0.0000049 copies/cm3, with a range of 0.0000000049 to 0.637 copies/cm3. The corresponding estimates for simulated coughing individuals were a mean of 0.277 copies/cm3 per cough, with a range of 0.000277 to 36 030 copies/cm3 per cough. The estimated concentrations in a room with an individual who was coughing frequently were very high, with a maximum of 7.44 million copies/m3 from an individual who was a high emitter. However, regular breathing from an individual who was a high emitter was modeled to result in lower room concentrations of up to 1248 copies/m3. CONCLUSIONS AND RELEVANCE In this modeling study, breathing and coughing were estimated to release large numbers of viruses, ranging from thousands to millions of virus copies per cubic meter in a room with an individual with COVID-19 with a high viral load, depending on ventilation and microdroplet formation process. The estimated infectious risk posed by a person with typical viral load who breathes normally was low. The results suggest that only few people with very high viral load pose an infection risk in poorly ventilated closed environments. These findings suggest that strict respiratory protection may be needed when there is a chance to be in the same small room with an individual, whether symptomatic or not, especially for a prolonged period.
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Affiliation(s)
- Michael Riediker
- Swiss Centre for Occupational and Environmental Health, Winterthur, Switzerland
| | - Dai-Hua Tsai
- Swiss Centre for Occupational and Environmental Health, Winterthur, Switzerland
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital of Psychiatry, University of Zurich, Zurich, Switzerland
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Bake B, Larsson P, Ljungkvist G, Ljungström E, Olin AC. Exhaled particles and small airways. Respir Res 2019; 20:8. [PMID: 30634967 PMCID: PMC6330423 DOI: 10.1186/s12931-019-0970-9] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 01/01/2019] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Originally, studies on exhaled droplets explored properties of airborne transmission of infectious diseases. More recently, the interest focuses on properties of exhaled droplets as biomarkers, enabled by the development of technical equipment and methods for chemical analysis. Because exhaled droplets contain nonvolatile substances, particles is the physical designation. This review aims to outline the development in the area of exhaled particles, particularly regarding biomarkers and the connection with small airways, i e airways with an internal diameter < 2 mm. MAIN BODY Generation mechanisms, sites of origin, number concentrations of exhaled particles and the content of nonvolatile substances are studied. Exhaled particles range in diameter from 0.01 and 1000 μm depending on generation mechanism and site of origin. Airway reopening is one scientifically substantiated particle generation mechanism. During deep expirations, small airways close and the reopening process produces minute particles. When exhaled, these particles have a diameter of < 4 μm. A size discriminating sampling of particles < 4 μm and determination of the size distribution, allows exhaled particle mass to be estimated. The median mass is represented by particles in the size range of 0.7 to 1.0 μm. Half an hour of repeated deep expirations result in samples in the order of nanogram to microgram. The source of these samples is the respiratory tract ling fluid of small airways and consists of lipids and proteins, similarly to surfactant. Early clinical studies of e g chronic obstructive pulmonary disease and asthma, reported altered particle formation and particle composition. CONCLUSION The physical properties and content of exhaled particles generated by the airway reopening mechanism offers an exciting noninvasive way to obtain samples from the respiratory tract lining fluid of small airways. The biomarker potential is only at the beginning to be explored.
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Affiliation(s)
- B. Bake
- Unit of Respiratory Medicine and Allergy, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - P. Larsson
- Unit of Occupational and Environmental Medicine, Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - G. Ljungkvist
- Unit of Occupational and Environmental Medicine, Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - E. Ljungström
- Atmospheric Science, Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - A-C Olin
- Unit of Occupational and Environmental Medicine, Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Bake B, Ljungström E, Claesson A, Carlsen HK, Holm M, Olin AC. Exhaled Particles After a Standardized Breathing Maneuver. J Aerosol Med Pulm Drug Deliv 2017; 30:267-273. [PMID: 28277815 DOI: 10.1089/jamp.2016.1330] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Particles in exhaled air (PEx) provide samples of respiratory tract lining fluid from small airways and offer a new opportunity to monitor pathological changes. The exhaled particles are produced by reopening of closed small airways and contain surfactant. The amount of PEx varies by orders of magnitude among subjects. A standardized breathing pattern reduces the variation, but it remains large and the reasons are unknown. The aim of the present study was to assess to what extent sex, age, body size, and spirometry results explain the interindividual variation of PEx among healthy middle-aged subjects. METHODS The PExA® instrument was used to measure PEx in 126 healthy middle-aged nonsmoking subjects participating in the European Respiratory Community Health Survey (ERCS-III). The subjects performed a standardized breathing maneuver involving expiration to residual volume, a breath-hold of 3 seconds, a full inspiration, and then a full expiration into the PExA instrument. PEx number concentrations were expressed per exhalation and per exhaled liter. Age and anthropometric and spirometric variables were analyzed as potential predictors. RESULTS PEx/L was consistently and negatively associated to lung size-related variables and accordingly lower in men than in women. PEx/Exhalation was similar in women and men. Increasing age was associated with increasing PEx. Reference equations are presented based on age, weight, and spirometry variables and independent of sex. These predictors explained 28%-29% of the interindividual variation. CONCLUSIONS The interindividual variation of PEx after a standardized breathing maneuver is large and the considered predictors explain a minor part only.
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Affiliation(s)
- Björn Bake
- 1 Department of Respiratory Medicine and Allergology, Sahlgrenska Academy at University of Gothenburg , Gothenburg, Sweden
| | - Evert Ljungström
- 2 Department of Chemistry and Molecular Biology, University of Gothenburg , Gothenburg, Sweden
| | - Annika Claesson
- 3 Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg, Sweden
| | - Hanne Krage Carlsen
- 3 Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg, Sweden
| | - Matthias Holm
- 3 Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg, Sweden
| | - Anna-Carin Olin
- 3 Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg , Gothenburg, Sweden
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Zamuruyev KO, Aksenov AA, Pasamontes A, Brown JF, Pettit DR, Foutouhi S, Weimer BC, Schivo M, Kenyon NJ, Delplanque JP, Davis CE. Human breath metabolomics using an optimized non-invasive exhaled breath condensate sampler. J Breath Res 2016; 11:016001. [PMID: 28004639 DOI: 10.1088/1752-7163/11/1/016001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Exhaled breath condensate (EBC) analysis is a developing field with tremendous promise to advance personalized, non-invasive health diagnostics as new analytical instrumentation platforms and detection methods are developed. Multiple commercially-available and researcher-built experimental samplers are reported in the literature. However, there is very limited information available to determine an effective breath sampling approach, especially regarding the dependence of breath sample metabolomic content on the collection device design and sampling methodology. This lack of an optimal standard procedure results in a range of reported results that are sometimes contradictory. Here, we present a design of a portable human EBC sampler optimized for collection and preservation of the rich metabolomic content of breath. The performance of the engineered device is compared to two commercially available breath collection devices: the RTube™ and TurboDECCS. A number of design and performance parameters are considered, including: condenser temperature stability during sampling, collection efficiency, condenser material choice, and saliva contamination in the collected breath samples. The significance of the biological content of breath samples, collected with each device, is evaluated with a set of mass spectrometry methods and was the primary factor for evaluating device performance. The design includes an adjustable mass-size threshold for aerodynamic filtering of saliva droplets from the breath flow. Engineering an inexpensive device that allows efficient collection of metalomic-rich breath samples is intended to aid further advancement in the field of breath analysis for non-invasive health diagnostic. EBC sampling from human volunteers was performed under UC Davis IRB protocol 63701-3 (09/30/2014-07/07/2017).
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Affiliation(s)
- Konstantin O Zamuruyev
- Department of Mechanical and Aerospace Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Tinglev ÅD, Ullah S, Ljungkvist G, Viklund E, Olin AC, Beck O. Characterization of exhaled breath particles collected by an electret filter technique. J Breath Res 2016; 10:026001. [DOI: 10.1088/1752-7155/10/2/026001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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11
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Lärstad M, Almstrand AC, Larsson P, Bake B, Larsson S, Ljungström E, Mirgorodskaya E, Olin AC. Surfactant Protein A in Exhaled Endogenous Particles Is Decreased in Chronic Obstructive Pulmonary Disease (COPD) Patients: A Pilot Study. PLoS One 2015; 10:e0144463. [PMID: 26656890 PMCID: PMC4676630 DOI: 10.1371/journal.pone.0144463] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/18/2015] [Indexed: 01/24/2023] Open
Abstract
Background Exhaled, endogenous particles are formed from the epithelial lining fluid in small airways, where surfactant protein A (SP-A) plays an important role in pulmonary host defense. Based on the knowledge that chronic obstructive pulmonary disease (COPD) starts in the small airway epithelium, we hypothesized that chronic inflammation modulates peripheral exhaled particle SP-A and albumin levels. The main objective of this explorative study was to compare the SP-A and albumin contents in exhaled particles from patients with COPD and healthy subjects and to determine exhaled particle number concentrations. Methods Patients with stable COPD ranging from moderate to very severe (n = 13), and healthy non-smoking subjects (n = 12) were studied. Subjects performed repeated breath maneuvers allowing for airway closure and re-opening, and exhaled particles were optically counted and collected on a membrane using the novel PExA® instrument setup. Immunoassays were used to quantify SP-A and albumin. Results COPD patients exhibited significantly lower SP-A mass content of the exhaled particles (2.7 vs. 3.9 weight percent, p = 0.036) and lower particle number concentration (p<0.0001) than healthy subjects. Albumin mass contents were similar for both groups. Conclusions Decreased levels of SP-A may lead to impaired host defense functions of surfactant in the airways, contributing to increased susceptibility to COPD exacerbations. SP-A in exhaled particles from small airways may represent a promising non-invasive biomarker of disease in COPD patients.
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Affiliation(s)
- Mona Lärstad
- Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
- * E-mail:
| | - Ann-Charlotte Almstrand
- Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Per Larsson
- Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Björn Bake
- Department of Respiratory Medicine and Allergology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Sven Larsson
- Department of Respiratory Medicine and Allergology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Evert Ljungström
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Ekaterina Mirgorodskaya
- Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Anna-Carin Olin
- Department of Occupational and Environmental Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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12
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Pantelic J, Tham KW, Licina D. Effectiveness of a personalized ventilation system in reducing personal exposure against directly released simulated cough droplets. INDOOR AIR 2015; 25:683-93. [PMID: 25615014 DOI: 10.1111/ina.12187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 01/15/2015] [Indexed: 05/07/2023]
Abstract
UNLABELLED The inhalation intake fraction was used as an indicator to compare effects of desktop personalized ventilation and mixing ventilation on personal exposure to directly released simulated cough droplets. A cough machine was used to simulate cough release from the front, back, and side of a thermal manikin at distances between 1 and 4 m. Cough droplet concentration was measured with an aerosol spectrometer in the breathing zone of a thermal manikin. Particle image velocimetry was used to characterize the velocity field in the breathing zone. Desktop personalized ventilation substantially reduced the inhalation intake fraction compared to mixing ventilation for all investigated distances and orientations of the cough release. The results point out that the orientation between the cough source and the breathing zone of the exposed occupant is an important factor that substantially influences exposure. Exposure to cough droplets was reduced with increasing distance between cough source and exposed occupant. PRACTICAL IMPLICATIONS The results from this study show that an advanced air distribution system such as personalized ventilation reduces exposure to cough-released droplets better than commonly applied overhead mixing ventilation. This work can inform HVAC engineers about different aspects of air distribution systems’ performance and can serve as an aid in making critical design decisions.
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Affiliation(s)
- J Pantelic
- School of Public Health, Maryland Institute for Applied Environmental Health, University of Maryland at College Park, College Park, MD, USA
| | - K W Tham
- Department of Building, School of Design and Environment, National University of Singapore, Singapore, Singapore
| | - D Licina
- Department of Building, School of Design and Environment, National University of Singapore, Singapore, Singapore
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Copenhagen, Denmark
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13
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Greguš M, Foret F, Kubáň P. Single-breath analysis using a novel simple sampler and capillary electrophoresis with contactless conductometric detection. Electrophoresis 2015; 36:526-33. [PMID: 25377628 DOI: 10.1002/elps.201400456] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 10/29/2014] [Accepted: 10/29/2014] [Indexed: 11/11/2022]
Abstract
The analysis of ionic content of exhaled breath condensate (EBC) from one single breath by CE with C(4) D is demonstrated for the first time. A miniature sampler made from a 2-mL syringe and an aluminum cooling cylinder for collection of EBC was developed. Various parameters of the sampler that influence its collection efficiency, repeatability, and effect of respiratory patterns were studied in detail. Efficient procedures for the cleanup of the miniature sampler were also developed and resulted in significant improvement of sampling repeatability. Analysis of EBC was performed by CE-C(4) D in a 60 mM MES/l-histidine BGE with 30 μM CTAB and 2 mM 18-crown-6 at pH 6 and excellent repeatability of migration times (RSD < 1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 12 inorganic anions, cations, and organic acids was obtained. It has been shown that the breathing pattern has a significant impact on the concentration of the analytes in the collected EBC. As the ventilatory pattern can be easily controlled during single exhalation, the developed collection system and method provides a highly reproducible and fast way of collecting EBC with applicability in point-of-care diagnostics.
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Affiliation(s)
- Michal Greguš
- Bioanalytical Instrumentation, CEITEC, Masaryk University, Brno, Czech Republic; Department of Chemistry, Masaryk University, Brno, Czech Republic
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14
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Berchtold C, Bosilkovska M, Daali Y, Walder B, Zenobi R. Real-time monitoring of exhaled drugs by mass spectrometry. MASS SPECTROMETRY REVIEWS 2014; 33:394-413. [PMID: 24272872 DOI: 10.1002/mas.21393] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 06/02/2023]
Abstract
Future individualized patient treatment will need tools to monitor the dose and effects of administrated drugs. Mass spectrometry may become the method of choice to monitor drugs in real time by analyzing exhaled breath. This review describes the monitoring of exhaled drugs in real time by mass spectrometry. The biological background as well as the relevant physical properties of exhaled drugs are delineated. The feasibility of detecting and monitoring exhaled drugs is discussed in several examples. The mass spectrometric tools that are currently available to analyze breath in real time are reviewed. The technical needs and state of the art for on-site measurements by mass spectrometry are also discussed in detail. Off-line methods, which give support and are an important source of information for real-time measurements, are also discussed. Finally, some examples of drugs that have already been successfully detected in exhaled breath, including propofol, fentanyl, methadone, nicotine, and valproic acid are presented. Real-time monitoring of exhaled drugs by mass spectrometry is a relatively new field, which is still in the early stages of development. New technologies promise substantial benefit for future patient monitoring and treatment.
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Affiliation(s)
- Christian Berchtold
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093, Zürich, Switzerland
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15
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Abstract
Over the past three decades, the goal of many researchers is analysis of exhaled breath condensate (EBC) as noninvasively obtained sample. A total quality in laboratory diagnostic processes in EBC analysis was investigated: pre-analytical (formation, collection, storage of EBC), analytical (sensitivity of applied methods, standardization) and post-analytical (interpretation of results) phases. EBC analysis is still used as a research tool. Limitations referred to pre-analytical, analytical, and post-analytical phases of EBC analysis are numerous, e.g. low concentrations of EBC constituents, single-analyte methods lack in sensitivity, and multi-analyte has not been fully explored, and reference values are not established. When all, pre-analytical, analytical and post-analytical requirements are met, EBC biomarkers as well as biomarker patterns can be selected and EBC analysis can hopefully be used in clinical practice, in both, the diagnosis and in the longitudinal follow-up of patients, resulting in better outcome of disease.
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Affiliation(s)
- Slavica Dodig
- Department of Clinical Laboratory Diagnosis, Srebrnjak Children's Hospital, Zagreb, Croatia.
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16
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Kubáň P, Foret F. Exhaled breath condensate: Determination of non-volatile compounds and their potential for clinical diagnosis and monitoring. A review. Anal Chim Acta 2013; 805:1-18. [DOI: 10.1016/j.aca.2013.07.049] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/16/2013] [Accepted: 07/20/2013] [Indexed: 12/31/2022]
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17
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Pantelic J, Tham KW. Adequacy of air change rate as the sole indicator of an air distribution system's effectiveness to mitigate airborne infectious disease transmission caused by a cough release in the room with overhead mixing ventilation: A case study. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/10789669.2013.842447] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Lindsley WG, King WP, Thewlis RE, Reynolds JS, Panday K, Cao G, Szalajda JV. Dispersion and exposure to a cough-generated aerosol in a simulated medical examination room. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2012; 9:681-90. [PMID: 23033849 PMCID: PMC4688889 DOI: 10.1080/15459624.2012.725986] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Few studies have quantified the dispersion of potentially infectious bioaerosols produced by patients in the health care environment and the exposure of health care workers to these particles. Controlled studies are needed to assess the spread of bioaerosols and the efficacy of different types of respiratory personal protective equipment (PPE) in preventing airborne disease transmission. An environmental chamber was equipped to simulate a patient coughing aerosol particles into a medical examination room, and a health care worker breathing while exposed to these particles. The system has three main parts: (1) a coughing simulator that expels an aerosol-laden cough through a head form; (2) a breathing simulator with a second head form that can be fitted with respiratory PPE; and (3) aerosol particle counters to measure concentrations inside and outside the PPE and at locations throughout the room. Dispersion of aerosol particles with optical diameters from 0.3 to 7.5 μm was evaluated along with the influence of breathing rate, room ventilation, and the locations of the coughing and breathing simulators. Penetration of cough aerosol particles through nine models of surgical masks and respirators placed on the breathing simulator was measured at 32 and 85 L/min flow rates and compared with the results from a standard filter tester. Results show that cough-generated aerosol particles spread rapidly throughout the room, and that within 5 min, a worker anywhere in the room would be exposed to potentially hazardous aerosols. Aerosol exposure is highest with no personal protective equipment, followed by surgical masks, and the least exposure is seen with N95 FFRs. These differences are seen regardless of breathing rate and relative position of the coughing and breathing simulators. These results provide a better understanding of the exposure of workers to cough aerosols from patients and of the relative efficacy of different types of respiratory PPE, and they will assist investigators in providing research-based recommendations for effective respiratory protection strategies in health care settings.
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Affiliation(s)
- William G Lindsley
- National Institute for Occupational Safety and Health, Health Effects Laboratory Division, 1095 Willowdale Road, Morgantown, WV 26505-2845, USA.
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19
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Chao CYH, Wan MP, Morawska L, Johnson GR, Ristovski ZD, Hargreaves M, Mengersen K, Corbett S, Li Y, Xie X, Katoshevski D. Characterization of expiration air jets and droplet size distributions immediately at the mouth opening. JOURNAL OF AEROSOL SCIENCE 2009. [PMID: 32287373 DOI: 10.1016/j.jaerosci.2011.07.009] [Citation(s) in RCA: 337] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 μm and it was 16.0 μm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm-3 per cough and 0.004-0.223 cm-3 for speaking.
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Affiliation(s)
- C Y H Chao
- Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - M P Wan
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - L Morawska
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - G R Johnson
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - Z D Ristovski
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - M Hargreaves
- International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD, Australia
| | - K Mengersen
- School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - S Corbett
- Centre for Population Health, Western Sydney West Area Health Service, Sydney, NSW, Australia
| | - Y Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - X Xie
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - D Katoshevski
- Department of Biotechnology and Environmental Engineering, Ben-Gurion University of Negev, Beer-Sheva, Israel
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