These indices indicate the time that has to pass until a certain percentage of the present COVID-19 concentration decays. Recent investigations showed that the decay of COVID-19 was enhanced by either increased humidity or temperature (Biryukov et al., 2020). Additionally, there is also a dependence on sunlight, which has an impact on the potential for aerosol transmission of COVID-19 (Schuit et al., 2020). The indices are based on the numbers of the SARS-CoV-2 Airborne Calculator published by Homeland Security.
Half-life of the virus outdoors in minutes:
Time in minutes until 90% of the virus died:
Time in minutes until 99% of the virus died:
The chart below shows the 90 % decay time of COVID-19 for North America, where the influece of heat in the south-western United States on the virus' lifetime can be seen:
Below is a time series that shows the 90 % and 99 % decay times of COVID-19 as well as the half life time for Zurich:
Biryukov J, Boydston JA, Dunning RA, Yeager JJ, Wood S, Reese AL, Ferris A, Miller D, Weaver W, Zeitouni NE, Phillips A, Freeburger D, Hooper I, Ratnesar-Shumate S, Yolitz J, Krause M, Williams G, Dawson DG, Herzog A, Dabisch P, Wahl V, Hevey MC, Altamura LA. 2020. Increasing temperature and relative humidity accelerates inactivation of SARS-CoV2 on surfaces. mSphere 5:e00441-20. https://doi.org/10.1128/mSphere.00441-20
Michael Schuit, Shanna Ratnesar-Shumate, Jason Yolitz, Gregory Williams, Wade Weaver, Brian Green, David Miller, Melissa Krause, Katie Beck, Stewart Wood, Brian Holland, Jordan Bohannon, Denise Freeburger, Idris Hooper, Jennifer Biryukov, Louis A Altamura, Victoria Wahl, Michael Hevey, Paul Dabisch, Airborne SARS-CoV-2 Is Rapidly Inactivated by Simulated Sunlight, The Journal of Infectious Diseases, Volume 222, Issue 4, 15 August 2020, Pages 564–571, https://doi.org/10.1093/infdis/jiaa334