Dispersion of expectorated cough droplets with seasonal influenza in an office

Physics of Fluids, Год журнала: 2023, Номер 35(8)

Опубликована: Авг. 1, 2023

We do not fully grasp viral droplet transmission processes in ventilated interior environments. The core focus of our research is to investigate the effectiveness protected occupied zone ventilation (POV) through computational fluid dynamics models a simplified office setting. large-eddy simulation technique with Eulerian–Lagrangian model was implemented address complicated indoor such as turbulence, flow–aerosol interaction, and impact. computationally investigated effects desk partitions POV on cough droplets an office. approach tested using two distinct exhaust layouts four different rates (1.0, 1.2, 1.5, 1.8 m/s). A comparative analysis flow fields, topologies, particle directions has been studied. findings indicate that plane jet's influence performance. distributed virus around room, but compared up-exhaust cases, down-exhaust cases appeared have better shielded healthy person. This pattern could placement outlet systems significantly influences aerosol dispersion. results also show substantial streams may carry tiny particles (≤70 μm) throughout their path. Large (≥100 go far gas clouds. Most deposit solid surfaces various work sites per specific rates. Office workers need be very cautious these hazardous areas.

Язык: Английский

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Review of factors affecting virus inactivation in aerosols and droplets

Journal of The Royal Society Interface, Год журнала: 2024, Номер 21(215)

Опубликована: Июнь 1, 2024

The inactivation of viruses in aerosol particles (aerosols) and droplets depends on many factors, but the precise mechanisms are not known. system involves complex physical biochemical interactions. We reviewed literature to establish current knowledge about these identify gaps. identified 168 relevant papers grouped results by following factors: virus type structure, or droplet size, temperature, relative humidity (RH) evaporation, chemical composition droplet, pH atmospheric composition. These factors influence dynamic microenvironment surrounding a virion thus may affect its inactivation. Results indicate that experience biphasic decay as carrier aerosols undergo evaporation equilibrate with air, their final state (liquid, semi-solid solid) RH. Virus stability, RH temperature interrelated, effects multifaceted still completely understood. Studies impact stability have raised new questions require further exploration. frequent practice studying large culture media limit our understanding for transmission, so we encourage use physiologically size future research.

Язык: Английский

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The effects of desk-partition layout on cough droplet dynamics relating to seasonal influenza

Physics of Fluids, Год журнала: 2024, Номер 36(1)

Опубликована: Янв. 1, 2024

The use of physical dividers as control measures for short-range viral transmission in indoor settings has gained increasing attention. However, the understanding regarding their correct usage under different seating arrangements is incomplete. In this study, we focused on assessing effectiveness impeding transient cough droplets three representative layouts using large-eddy simulation technique with Eulerian–Lagrangian model. We computationally also investigated effects ventilation droplet desk-divider layouts. approach was tested two rates (1.0 and 1.8 m/s). A comparative analysis flow fields, topologies, particle directions been studied. findings indicate that sitting arrangements, rates, partition play a significant role designing effective infection office setup considered. protected occupied zone (POV) worked best situations low m/s) cross-partition protecting healthy persons. addition, POV performed well high (1.8 face-to-face layout. side-by-side configuration poorly considered person seated directly opposite infected person. numerical predictions may be used to validate other experimental studies educate workers engineers airborne control.

Язык: Английский

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Mechanisms controlling the transport and evaporation of human exhaled respiratory droplets containing the severe acute respiratory syndrome coronavirus: a review

Environmental Chemistry Letters, Год журнала: 2023, Номер 21(3), С. 1701 - 1727

Опубликована: Фев. 22, 2023

Transmission of the coronavirus disease 2019 is still ongoing despite mass vaccination, lockdowns, and other drastic measures to control pandemic. This due partly our lack understanding on multiphase flow mechanics that droplet transport viral transmission dynamics. Various models evaporation have been reported, yet there limited knowledge about influence physicochemical parameters respiratory droplets carrying severe acute syndrome 2. Here we review effects initial size, environmental conditions, virus mutation, non-volatile components dispersion, stability. We present experimental computational methods analyze transport, factors controlling evaporation. Methods include thermal manikins, techniques, aerosol-generating nucleic acid-based assays, antibody-based polymerase chain reaction, loop-mediated isothermal amplification, field-effect transistor-based assay, discrete gas-phase modeling. Controlling turbulence, ventilation, ambient temperature, relative humidity, size distribution, components, mutation. Current results show medium-sized droplets, e.g., 50 µm, are sensitive humidity. Medium-sized experience delayed at high increase airborne lifetime travel distance. By contrast, low quickly shrink nuclei follow cough jet. Virus inactivation within a few hours generally occurs temperatures above 40 °C, presence particles in aerosols impedes

Язык: Английский

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Study on the evaporation characteristics of self-rewetting droplets on different wettability surfaces

International Journal of Thermal Sciences, Год журнала: 2025, Номер 211, С. 109698 - 109698

Опубликована: Янв. 11, 2025

Язык: Английский

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Infectious cough droplet dynamics in a makeshift hospital isolation ward

Physics of Fluids, Год журнала: 2025, Номер 37(2)

Опубликована: Фев. 1, 2025

The COVID-19 pandemic highlighted the need for rapidly deployable healthcare facilities, leading to increased use of modular construction methods. Nonetheless, knowledge about airflow patterns and spread bioaerosols in these wards remains insufficient, potentially heightening risk cross-infection among workers patients. This paper presents a ventilation design negative-pressure ward aimed at reducing infectious particles. We investigate effects various designs, patient postures (sitting supine), air changes per hour (ACH) on cough droplets an airborne infection isolation room using large eddy simulation Eulerian–Lagrangian model. Findings show that ceiling exhaust grilles (design 2) resulted lowest radial dispersion (3.64 m) 12 ACH, while sidewall exhausts (baseline) performed best higher ACH levels. Seated patients had quicker droplet evaporation compared those supine position. setups survival included bed's bottom ceiling, maintaining minimum ACH. Cases 5 13, with over patient's head bottom, showed concentrations DPM, under 0.008 km−3 near source less than 0.001 mid-room. Sitting posture consistently led lower DPM concentrations. research emphasizes critical role placement re-circulation transmission risks, ultimately contributing improved strategies control AII rooms.

Язык: Английский

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Influence of indoor environmental conditions on airborne transmission and lifetime of sneeze droplets in a confined space: a way to reduce COVID-19 spread

Environmental Science and Pollution Research, Год журнала: 2023, Номер 30(15), С. 44067 - 44085

Опубликована: Янв. 21, 2023

Язык: Английский

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Comprehensive Computational Study on the Influences of Particle Size and Relative Humidity on Aerosol/Droplet Transmission in a Ventilated Room Under Stationary and Dynamic Conditions

Indoor Air, Год журнала: 2024, Номер 2024(1)

Опубликована: Янв. 1, 2024

Given the concerns surrounding possibility of crosscontamination caused by airborne transmission respiratory aerosols (> 5 μ m in diameter) and droplets containing infectious viruses, there is a great need for simulations that reliably characterize behaviour these particles real‐world scenarios. This study performs comprehensive transient CFD analysis to investigate virus‐carrying released through coughing mobile patient within typical room equipped with ventilation system. computational elaborately examines how particle size relative humidity impact dispersion carrying virus both stationary conditions patients. To enhance accuracy this study, effective factors such as evaporation liquid content random distribution particles, along considerations buoyancy, drag, lift, Brownian motion, gravitational forces, are taken into account. influence aerosol droplet size, considers uniform distributions 1, 10, 100 diameter, comprising 98.2% water 1.8% solid content. Additionally, different levels, 0%, 50%, 90%, incorporated indicate their on pattern residence time dynamic According results, high levels individuals’ movement significantly affect turbulence intensity, airflow pattern, travelling distance, trajectory air pressure, density environments.

Язык: Английский

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Numerical investigation of the role of human motion in the spread of virus-laden droplets from coughing using CFD dynamic mesh technique

European Journal of Mechanics - B/Fluids, Год журнала: 2024, Номер 111, С. 42 - 60

Опубликована: Дек. 15, 2024

Язык: Английский

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Decay rate estimation of respiratory viruses in aerosols and on surfaces under different environmental conditions

International Journal of Hygiene and Environmental Health, Год журнала: 2023, Номер 251, С. 114187 - 114187

Опубликована: Май 19, 2023

Язык: Английский

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