Towards improved social distancing guidelines: Space and time dependence of virus transmission from speech-driven aerosol transport between two individuals

Yang, Fan; Pahlavan, Amir A.; Mendez, Simon; Abkarian, Manouk; Stone, Howard A.

doi:10.1103/physrevfluids.5.122501

Cited by 78 publications

(128 citation statements)

References 31 publications

Supporting

Mentioning

117

Contrasting

Order By: Relevance

“…[7] corresponds to the risk of transmission from respiratory jets deduced by Yang et al . (96), aside from the factor p p . We note that any such guideline intended to mitigate against short-range airborne transmission by respiratory plumes will be, as is [7], dependent on geometry, flow and human behavior, while our guideline for the mitigation of long-range airborne transmission [5] is universal.…”

Section: Application To Covid-19mentioning

confidence: 99%

Beyond Six Feet: A Guideline to Limit Indoor Airborne Transmission of COVID-19

Bazant

Bush

2020

Preprint

View full text Add to dashboard Cite

The revival of the global economy is being predicated on the Six-Foot Rule, a guideline that offers little protection from pathogen-bearing droplets sufficiently small to be continuously mixed through an indoor space. The importance of indoor, airborne transmission of COVID-19 is now widely recognized; nevertheless, no quantitative measures have been proposed to protect against it. In this article, we build upon models of airborne disease transmission in order to derive a safety guideline that would impose a precise upper bound on the cumulative exposure time, the product of the number of occupants and their time in an enclosed space. We demonstrate the manner in which this bound depends on the ventilation rate and dimensions of the room; the breathing rate, respiratory activity and face-mask use of its occupants; and the infectiousness of the respiratory aerosols, a disease-specific parameter that we estimate from available data. Case studies are presented, implications for contact tracing considered, and appropriate caveats enumerated.

show abstract

Section: Application To Covid-19mentioning

confidence: 99%

Beyond Six Feet: A Guideline to Limit Indoor Airborne Transmission of COVID-19

Bazant

Bush

2020

Preprint

View full text Add to dashboard Cite

show abstract

“…This situation has been analyzed recently for speech-driven aerosol transport including time dependence. 83 U ∞ significantly exceeds V j ; this could correspond, for instance, to a person breathing normally with an expiratory velocity of ∼1 m/s 84 on a windy day with wind velocities upwards of 10 miles/h. Neglecting buoyancy effects, this situation can be modeled as a horizontal plume from a point source in a crossflow, and studies 85,86 suggest that C ( x ) ∼ x −3/2 beyond the near-field region.…”

Section: Model Predictionsmentioning

confidence: 99%

“…Here, we employ data generated from a wall-modeled large-eddy simulation 87 of a plume from a point source located 1.5 m above the ground in a turbulent atmospheric boundary layer, with a mean wind velocity corresponding to 2 m/s. 83 The model is designed to mimic normal breathing with the scalar (representing the respiratory aerosol) being released as puffs at regular intervals of 3 s. The exhaled breath is assumed to be at a temperature of 37 °C, and two ambient temperature conditions are considered: 0 °C and 42 °C. In the model, buoyancy effects are included using the Boussinesq approximation.…”

Section: Model Predictionsmentioning

confidence: 99%

“…This situation has been analyzed recently for speech-driven aerosol transport including time dependence. 83 …”

Section: Model Predictionsmentioning

confidence: 99%

“… 35 The inequality assumes that the rate of arrival of virion-bearing aerosols in the vicinity of the susceptible is constant in time. The recent analysis 83 of speech driven aerosol transport takes into account the start time and travel duration in scenario (2) treated in Sec. VIII .…”

Section: Caveatsmentioning

confidence: 99%

See 2 more Smart Citations

A mathematical framework for estimating risk of airborne transmission of COVID-19 with application to face mask use and social distancing

2020

View full text Add to dashboard Cite

A mathematical model for estimating the risk of airborne transmission of a respiratory infection such as COVID-19 is presented. The model employs basic concepts from fluid dynamics and incorporates the known scope of factors involved in the airborne transmission of such diseases. Simplicity in the mathematical form of the model is by design so that it can serve not only as a common basis for scientific inquiry across disciplinary boundaries but it can also be understandable by a broad audience outside science and academia. The caveats and limitations of the model are discussed in detail. The model is used to assess the protection from transmission afforded by face coverings made from a variety of fabrics. The reduction in the transmission risk associated with increased physical distance between the host and susceptible is also quantified by coupling the model with available and new large eddy simulation data on scalar dispersion in canonical flows. Finally, the effect of the level of physical activity (or exercise intensity) of the host and the susceptible in enhancing the transmission risk is also assessed.

show abstract

From Microscopic Droplets to Macroscopic Crowds: Crossing the Scales in Models of Short‐Range Respiratory Disease Transmission, with Application to COVID‐19

2023

Self Cite

View full text Add to dashboard Cite

Short‐range exposure to airborne virus‐laden respiratory droplets is an effective transmission route of respiratory diseases, as exemplified by Coronavirus Disease 2019 (COVID‐19). In order to assess the risks associated with this pathway in daily‐life settings involving tens to hundreds of individuals, the chasm needs to be bridged between fluid dynamical simulations and population‐scale epidemiological models. This is achieved by simulating droplet trajectories at the microscale in numerous ambient flows, coarse‐graining their results into spatio‐temporal maps of viral concentration around the emitter, and coupling these maps to field‐data about pedestrian crowds in different scenarios (streets, train stations, markets, queues, and street cafés). At the individual scale, the results highlight the paramount importance of the velocity of the ambient air flow relative to the emitter's motion. This aerodynamic effect, which disperses infectious aerosols, prevails over all other environmental variables. At the crowd's scale, the method yields a ranking of the scenarios by the risks of new infections, dominated by the street cafés and then the outdoor market. While the effect of light winds on the qualitative ranking is fairly marginal, even the most modest air flows dramatically lower the quantitative rates of new infections.

show abstract

Towards improved social distancing guidelines: Space and time dependence of virus transmission from speech-driven aerosol transport between two individuals

Cited by 78 publications

References 31 publications

Beyond Six Feet: A Guideline to Limit Indoor Airborne Transmission of COVID-19

Beyond Six Feet: A Guideline to Limit Indoor Airborne Transmission of COVID-19

A mathematical framework for estimating risk of airborne transmission of COVID-19 with application to face mask use and social distancing

From Microscopic Droplets to Macroscopic Crowds: Crossing the Scales in Models of Short‐Range Respiratory Disease Transmission, with Application to COVID‐19

Contact Info

Product

Resources

About