Survival of Expiratory Aerosols in a Room: Study Using a Bi-compartment and Bi-component Indoor Air Model

Bathula, Sreekanth; Anand, S.; Thajudeen, Thaseem; Mayya, Y. S.; Chaudhury, Probal; Chaturvedi, S.

doi:10.4209/aaqr.200547

Cited by 12 publications

(6 citation statements)

References 53 publications

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“…Therefore, the use of mask and face shield should be used to prevent the virus [44][45][46]. The maintenance of ventilation in indoor situation is also very crucial to avoid the infection [48,49]. The maintenance of only a social distance of 2 meter as norm to avoid the virus is not corroborated by the present investigation because the aerosol created by the evaporation may remained suspended in the air for more than an hour.…”

Section: Summary and Discussionmentioning

confidence: 71%

Airborne virus transmission under different weather conditions

Das,

Alam,

Plumari

et al. 2021

Preprint

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The COVID19 infection is known to be disseminated through the droplets ejected by infected individual during coughing, sneezing, speaking and breathing. The spread of the infection and hence its menace will depend on how the virus-loaded droplets evolve in space and time with changing environmental conditions. In view of this, we investigate here the evolution of the droplets under the purview of the Brownian motion of the evaporating droplets in the air under the action of gravity with varying weather conditions of relative humidity, temperature and wind flow. We track the movement of the droplets till either they gravitationally settle on the ground or evaporate to aerosols of size 2µm or below and remain suspended in the air. The correction to drag force required for flow of droplets beyond the laminar regime has been taken into consideration. We find that on the one hand the larger evaporating droplets falls on the ground under the action of gravity and on the other hand the smaller evaporating droplets generate aerosols. The intermediate size droplets are very sensitive to the weather conditions which decides whether the intermediate size droplets will settle in the ground gravitationally or evaporate to aerosol. Therefore, it is clear that the weather condition play crucial in deciding the intensity of spreading of the infection. Since all the possible interactions of the droplets with the surroundings are taken into consideration the results obtained here can be applied for both big as well as small droplets. The effects of relative humidity and temperature on the evaporation of the droplet are found to be significant. It is also noted that under strong wind flow the droplet can travel large distances. These weather dependence effects indicate that the maintenance of physical separation to evade the virus is not corroborated and hence the use of face mask becomes indispensable.

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Section: Summary and Discussionmentioning

confidence: 71%

Airborne virus transmission under different weather conditions

Das,

Alam,

Plumari

et al. 2021

Preprint

View full text Add to dashboard Cite

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“…In other words, large droplets settled faster than they evaporated, whereas small droplets evaporated faster than they settled (Bourouiba, 2020 ; Wells, 1934 ). Similarly, Bathula et al ( 2021 ) reported that the diameter of the dry droplet nuclei decreased to 32% of the original diameter of the wet droplet due to evaporation. In the present study, the droplets with the diameters 1 and 6 μm were capable of complete evaporation and remained in the air for about 5 min as the droplet nuclei with SARS-CoV-2 at midnight and midday, respectively.…”

Section: Resultsmentioning

confidence: 89%

A model for indoor motion dynamics of SARS-CoV-2 as a function of respiratory droplet size and evaporation

Aydin

Savas

Evrendilek

et al. 2021

Environ Monit Assess

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A simplified model has been devised to estimate the falling dynamics of severe acute respiratory syndrome corona-virus 2 (SARS-CoV-2)-laden droplets in an indoor environment. Our estimations were compared to existing literature data. The spread of SARS-CoV-2 is closely coupled to its falling dynamics as a function of respiratory droplet diameter (1 to 2000 μm) of an infected person and droplet evaporation. The falling time of SARS-CoV-2 with a respiratory droplet diameter of about 300 μm from a height of 1.7 m remained almost the same among the Newtonian lift equation, Stokes’s law, and our simplified model derived from them so as to account for its evaporation. The evaporative demand peaked at midday which was ten times that at midnight. The evaporating droplets 6 μm lost their water content rapidly, making their lifetimes in the air shorter than their falling times. The droplets 6 μm were able to evaporate completely and remained in the air for about 5 min as droplet nuclei with SARS-CoV-2.

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“…A N U S C R I P T 3 sneeze, and talking produced from the oral cavity (Johnson et al, 2011;Lee et al, 2019;Stadnytskyi et al, 2021;El Hassan et al, 2022), as well as aerosol dispersion inside a room (Inthavong et al, 2013;Heschl et al, 2014;Ji et al, 2018;Tao et al, 2020;Bathula et al, 2021;Crawford et al, 2021;Shah et al, 2021;Shrestha et al, 2021) and outdoor environments (Feng et al, 2020;Gorbunov, 2021). Additionally, studies (Zhu et al, 2006;Scharfman et al, 2016) demonstrated the oral cough produced a droplet-laden cough jet and puff dynamics, as well as review articles on the fluid dynamics of respiratory droplets (Dbouk and Drikakis, 2020;Mittal et al, 2020;Katre et al, 2021), and mitigation strategies for reducing viral transmission (Hui et al, 2012;Khosronejad et al, 2020;Salati et al, 2021).…”

Section: A C C E P T E D Mmentioning

confidence: 99%

Exhaled Jet and Viral-Laden Aerosol Transport from Nasal Sneezing

Salati

Fletcher

Khamooshi

et al. 2022

Aerosol Air Qual. Res.

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The recognition that the spread of COVID-19 is primarily through airborne transmission has brought renewed urgency to understand the spread of aerosols generated from patients. Viral-laden aerosols generated from oral coughs have been well studied; however, aerosols generated from nasal sneezing has been overlooked. This scenario arises from patients who suffer allergenic rhinosinusitis, or the nasal cavity is irritated, particularly during naso-endoscopy. Nasal sneezing is characterised by an explosive blast of air exiting the nostrils, which can be considered as dual jets, resulting in the spread of viral-laden aerosols remaining suspended in the air. This study used computational fluid dynamics consisting of a hybrid RANS-LES turbulence method to model the airflow and the discrete phase model to track aerosol dispersion during nasal sneezing. The results demonstrated that the exhaled airflow jets during nasal sneezing resemble the flow characteristics of two parallel jets in co-flow. These two jets interfere with each other in the merging zone, and after they merge, the sneeze plume expands radially. The nasal sneeze forms a V-shaped plume with smaller particles in the core region. At the end of the sneeze, when the exhaled jets have lost their initial momentum, the large particle dispersion is dominated by gravity. We detected the presence of a 'sneeze puff' that transport droplets away from the body, similar to the buoyant puff observed in recent COVID-19 studies of oral coughs.

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Survival of Expiratory Aerosols in a Room: Study Using a Bi-compartment and Bi-component Indoor Air Model

Cited by 12 publications

References 53 publications

Airborne virus transmission under different weather conditions

Airborne virus transmission under different weather conditions

A model for indoor motion dynamics of SARS-CoV-2 as a function of respiratory droplet size and evaporation

Exhaled Jet and Viral-Laden Aerosol Transport from Nasal Sneezing

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