Dispersion of expectorated cough droplets with seasonal influenza in an office

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(8)

Published: Aug. 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.

Language: Английский

---

Review of factors affecting virus inactivation in aerosols and droplets

Journal of The Royal Society Interface, Journal Year: 2024, Volume and Issue: 21(215)

Published: June 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.

Language: Английский

---

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

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(1)

Published: Jan. 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.

Language: Английский

---

Characteristics of droplets emission immediately around mouth during dental treatments

Building and Environment, Journal Year: 2023, Volume and Issue: 248, P. 111066 - 111066

Published: Nov. 25, 2023

Language: Английский

---

High instantaneous response quartz crystal microbalance humidity sensor for respiratory droplet detection

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 161366 - 161366

Published: March 1, 2025

Language: Английский

---

Infectious cough droplet dynamics in a makeshift hospital isolation ward

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(2)

Published: Feb. 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.

Language: Английский

---

Cough airflow dynamics and droplet transmission: Methods, characteristics, and implications

Building and Environment, Journal Year: 2025, Volume and Issue: unknown, P. 112974 - 112974

Published: April 1, 2025

Language: Английский

---

Temporal and Spatial Distribution of SARS-CoV-2 Aerosols in a Large-Scale Fangcang Shelter Hospital in Shanghai, China

Engineering, Journal Year: 2023, Volume and Issue: 28, P. 222 - 233

Published: July 7, 2023

The coronavirus disease 2019 (COVID-19) pandemic caused by frequently mutating severe acute respiratory syndrome 2 (SARS-CoV-2) has had a worldwide impact. However, detailed data on the potential aerosol transmission of SARS-CoV-2 in real-world and controlled laboratory settings remain sparse. During COVID-19 Shanghai, China 2022, samples were collected Fangcang shelter hospital, large-scale temporary hospital rapidly built converting existing National Exhibition Convention Center (Shanghai) into health care facility. Aerosol at different sites intervals around patients public areas, surface samples, pharyngeal swab from corresponding included. Samples tested for using real-time quantitative polymerase chain reaction (RT-qPCR) assays, followed sequencing if cycle threshold (Ct) value was < 30. positivity rate high contaminated zones (37.5%, 104/277), especially bed (41.2%, 68/165) near ventilation inlets (45.2%, 14/31). prevalence bed, air exhaust vents fluctuated closely related to among sampling sites. Some personal protective equipment medical staff rates. Sixty sequences joined ORF1ab spike genes obtained sixty represented two main clusters Omicron SARS-CoV-2. There consistency virus same patient their environment, detected matched those strains circulation during collection periods, which indicated likelihood cross-contamination hospital. In summary, results provide real landscape patient-centered view contamination large enclosed spaces offer useful guide taking targeted measures avoid nosocomial infections management or other diseases

Language: Английский

---

The effects of ventilation layout on cough droplet dynamics relating to seasonal influenza

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(11)

Published: Nov. 1, 2024

The primary aim of this paper is to investigate airborne virus transmission in a typical meeting room relating the heating, ventilation, and air conditioning (A.C.) systems. While installation 4-way cassette A.C. systems offices rooms has become increasingly common, their efficiency mitigating short-range spread remains poorly understood. Addressing gap critical post-pandemic era, where understanding limitations various ventilation paramount for public health. We systematically compare performance A.C., configurations mixing displacement systems, natural controlling respiratory viruses. Our research uniquely integrates evaporation models accurately simulate cough clouds' multiphase behavior under both quiescent thermally influenced conditions. study benchmarks these against two widely recognized standards (i.e., 5 changes per hour 10 l/s person), offering evidence-based insights applicable across diverse indoor settings. findings reveal significant thermal effects case, resulting 32.3%, 54.3%, 8.0% axial, vertical, lateral virus-laden droplets, respectively. Notably, 0.5 m/s system demonstrated superior performance, reducing axial by 29.6% compared other mechanical configurations. Furthermore, role exhaust outlets or doors was found be shaping pattern scenarios. This work can offer practical guidance office workers, engineers, health officials on enhancing infection control.

Language: Английский

---

Expiratory aerosols' spread, removing and infection risk investigation in public toilet: CFD and machine learning

Journal of Building Engineering, Journal Year: 2024, Volume and Issue: 97, P. 110725 - 110725

Published: Sept. 12, 2024

Language: Английский

---