Jet Fans in the Underground Car Parks and Virus Transmission&amp;nbsp;

Nazari, Ata; Jafari, Moharram; Rezaei, Naser; Taghizadeh‐Hesary, Farzad

doi:10.21203/rs.3.rs-93879/v1

Cited by 6 publications

(7 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The simulation-based study of an COVID-19 outbreak in a restaurant was examined by Liu et al , 23 showing the influence of the air-conditioning. The transmission of aerosols in underground car parking areas by fans was presented by Nazari et al , 24 identifying critical zones. An analysis of the particle transmission in school buses was presented by Zhang et al 25 The influence of HVAC systems and open windows was determined with a CFD analysis.…”

Section: Introductionmentioning

confidence: 99%

Transmission and reduction of aerosols in classrooms using air purifier systems

Burgmann

Janoske

2021

Physics of Fluids

View full text Add to dashboard Cite

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 μ m), 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.

show abstract

Section: Introductionmentioning

confidence: 99%

Transmission and reduction of aerosols in classrooms using air purifier systems

Burgmann

Janoske

2021

Physics of Fluids

View full text Add to dashboard Cite

show abstract

“…6 Thus, understanding how particles are transported by the action of moving fluids is key in designing and implementing preventative strategies including the use of masks, 7–9 indoor ventilation, 10,11 and social distancing measures. 12 Numerical simulations of specific indoor and public transportation environments such as isolation rooms, 13 airliner cabin sections, 14 urban buses, 15 elevators, 16 parking areas, 17 restaurants, 18 and offices 19 have been conducted in order to design robust transmission mitigation strategies.…”

Section: Introductionmentioning

confidence: 99%

Direct numerical simulation of turbulent dispersion of evaporative aerosol clouds produced by an intense expiratory event

et al. 2021

View full text Add to dashboard Cite

Airborne particles are a major route for transmission of COVID-19 and many other infectious diseases. When a person talks, sings, coughs, or sneezes, nasal and throat secretions are spewed into the air. After a short initial fragmentation stage, the expelled material is mostly composed of spherical particles of different sizes. While the dynamics of the largest droplets are dominated by gravitational effects, the smaller aerosol particles, mostly transported by means of hydrodynamic drag, form clouds that can remain afloat for long times. In subsaturated air environments, the dependence of pathogen-laden particle dispersion on their size is complicated due to evaporation of the aqueous fraction. Particle dynamics can significantly change when ambient conditions favor rapid evaporation rates that result in a transition from buoyancy-to-drag dominated dispersion regimes. To investigate the effect of particle size and evaporation on pathogen-laden cloud evolution, a direct numerical simulation of a mild cough was coupled with an evaporative Lagrangian particle advection model. The results suggest that while the dispersion of cough particles in the tails of the size distribution are unlikely to be disrupted by evaporative effects, preferential aerosol diameters (30–40 μ m) may exhibit significant increases in the residence time and horizontal range under typical ambient conditions. Using estimations of the viral concentration in the spewed fluid and the number of ejected particles in a typical respiratory event, we obtained a map of viral load per volume of air at the end of the cough and the number of virus copies per inhalation in the emitter vicinity.

show abstract

“…Zhang et al (2021) simulated aerosol transport in urban buses under different ventilation rates, with and without fresh air ventilation, and the impact of mask-wearing in this environment. Nazari et al (2021) studied the role of ventilation in underground car parking structures, which can produce hazardous areas with respect to aerosol inhalation when walking through the car park.…”

Section: Introductionmentioning

confidence: 99%

Computer simulation of the SARS-CoV-2 contamination risk in a large dental clinic

Komperda

Peyvan

et al. 2021

Physics of Fluids

View full text Add to dashboard Cite

COVID-19, caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus, has been rapidly spreading worldwide since December 2019, causing a public health crisis. Recent studies showed SARS-CoV-2's ability to infect humans via airborne routes. These motivated the study of aerosol and airborne droplet transmission in a variety of settings. This study performs a large-scale numerical simulation of a real-world dentistry clinic that contains aerosol-generating procedures. The simulation tracks the dispersion of evaporating droplets emitted during ultrasonic dental scaling procedures. The simulation considers 25 patient treatment cubicles in an open plan dentistry clinic. The droplets are modeled as having a volatile (evaporating) and nonvolatile fraction composed of virions, saliva, and impurities from the irrigant water supply. The simulated clinic's boundary and flow conditions are validated against experimental measurements of the real clinic. The results evaluate the behavior of large droplets and aerosols. We investigate droplet residence time and travel distance for different droplet diameters, surface contamination due to droplet settling and deposition, airborne aerosol mass concentration, and the quantity of droplets that escape through ventilation. The simulation results raise concerns due to the aerosols' long residence times (averaging up to 7.31 min) and travel distances (averaging up to 24.45 m) that exceed social distancing guidelines. Finally, the results show that contamination extends beyond the immediate patient treatment areas, requiring additional surface disinfection in the clinic. The results presented in this research may be used to establish safer dental clinic operating procedures, especially if paired with future supplementary material concerning the aerosol viral load generated by ultrasonic scaling and the viral load thresholds required to infect humans.

show abstract

Jet Fans in the Underground Car Parks and Virus Transmission

Cited by 6 publications

References 23 publications

Transmission and reduction of aerosols in classrooms using air purifier systems

Transmission and reduction of aerosols in classrooms using air purifier systems

Direct numerical simulation of turbulent dispersion of evaporative aerosol clouds produced by an intense expiratory event

Computer simulation of the SARS-CoV-2 contamination risk in a large dental clinic

Contact Info

Product

Resources

About