Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Nov 1;32(11):111706.
doi: 10.1063/5.0033306.

How coronavirus survives for days on surfaces

Rajneesh Bhardwaj  1 , Amit Agrawal  1
Affiliations

How coronavirus survives for days on surfaces

Rajneesh Bhardwaj et al. Phys Fluids (1994). .

Abstract

Our previous study [R. Bhardwaj and A. Agrawal, "Likelihood of survival of coronavirus in a respiratory droplet deposited on a solid surface," Phys. Fluids 32, 061704 (2020)] showed that the drying time of typical respiratory droplets is on the order of seconds, while the survival time of the coronavirus on different surfaces was reported to be on the order of hours in recent experiments. We attribute the long survival time of the coronavirus on a surface to the slow evaporation of a thin nanometer liquid film remaining after the evaporation of the bulk droplet. Accordingly, we employ a computational model for a thin film in which the evaporating mass rate is a function of disjoining and Laplace pressures inside the film. The model shows a strong dependence on the initial thickness of the film and suggests that the drying time of this nanometric film is on the order of hours, consistent with the survival time of the coronavirus on a surface, seen in published experiments. We briefly examine the change in the drying time as a function of the contact angle and type of surface. The computed time-varying film thickness or volume qualitatively agrees with the measured decay of the coronavirus titer on different surfaces. The present work provides insights on why coronavirus survival is on the order of hours or days on a solid surface under ambient conditions.

PubMed Disclaimer

Figures

FIG. 1.
FIG. 1.
Schematic of the problem considered in the present study. A respiratory droplet deposits on a surface as a sessile spherical cap and evaporates by diffusion of liquid vapor in air. The present study focuses on the evaporation of the thin film that forms in the later stages of the evaporation.
FIG. 2.
FIG. 2.
(a) Time-varying film thickness of a water film on a glass surface of initial film thickness h0 = 400 nm. (b) Evolution of disjoining and Laplace pressures inside the film. (c) Comparison among the time-varying film thickness of a water film on a glass surface for three cases of initial film thickness: h0 = 400 nm, 600 nm, and 800 nm.
FIG. 3.
FIG. 3.
Time-varying evaporating film thickness (h, red dashed line) and virus titer (V, blue circles) plotted on the left and right y axes, respectively. The frames in the left and right column correspond to 5 μl and 50 μl droplets, respectively. Virus titer for four different surfaces, namely, glass, copper, plastic (polypropylene), and stainless steel, are plotted, as reported in recent experiments. The initial film thickness in simulations is taken as 400 nm in all cases.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Dbouk T. and Drikakis D., “On coughing and airborne droplet transmission to humans,” Phys. Fluids 32, 053310 (2020).10.1063/5.0011960 - DOI - PMC - PubMed
    1. Dbouk T. and Drikakis D., “On respiratory droplets and face masks,” Phys. Fluids 32, 063303 (2020).10.1063/5.0015044 - DOI - PMC - PubMed
    1. Bhardwaj R. and Agrawal A., “Likelihood of survival of coronavirus in a respiratory droplet deposited on a solid surface,” Phys. Fluids 32, 061704 (2020).10.1063/5.0012009 - DOI - PMC - PubMed
    1. Bhardwaj R. and Agrawal A., “Tailoring surface wettability to reduce chances of infection of COVID-19 by a respiratory droplet and to improve the effectiveness of personal protection equipment,” Phys. Fluids 32, 081702 (2020).10.1063/5.0020249 - DOI - PMC - PubMed
    1. Agrawal A. and Bhardwaj R., “Reducing chances of COVID-19 infection by a cough cloud in a closed space,” Phys. Fluids 32(10), 101704 (2020).10.1063/5.0029186 - DOI - PMC - PubMed

LinkOut - more resources