Airborne SARS-CoV-2 Is Rapidly Inactivated by Simulated Sunlight

J Infect Dis. 2020 Jul 23;222(4):564-571. doi: 10.1093/infdis/jiaa334.


Aerosols represent a potential transmission route of COVID-19. This study examined effect of simulated sunlight, relative humidity, and suspension matrix on stability of SARS-CoV-2 in aerosols. Simulated sunlight and matrix significantly affected decay rate of the virus. Relative humidity alone did not affect the decay rate; however, minor interactions between relative humidity and other factors were observed. Mean decay rates (± SD) in simulated saliva, under simulated sunlight levels representative of late winter/early fall and summer were 0.121 ± 0.017 min-1 (90% loss, 19 minutes) and 0.306 ± 0.097 min-1 (90% loss, 8 minutes), respectively. Mean decay rate without simulated sunlight across all relative humidity levels was 0.008 ± 0.011 min-1 (90% loss, 286 minutes). These results suggest that the potential for aerosol transmission of SARS-CoV-2 may be dependent on environmental conditions, particularly sunlight. These data may be useful to inform mitigation strategies to minimize the potential for aerosol transmission.

Keywords: COVID-19; SARS-CoV-2; aerosol decay; aerosol persistence; relative humidity; sunlight.

MeSH terms

  • Aerosols
  • Air Microbiology*
  • Animals
  • Betacoronavirus / radiation effects*
  • COVID-19
  • Chlorocebus aethiops
  • Computer Simulation
  • Coronavirus Infections / transmission*
  • Culture Media
  • Humidity
  • Hydrogen-Ion Concentration
  • Pandemics
  • Pneumonia, Viral / transmission*
  • Regression Analysis
  • SARS-CoV-2
  • Saliva / chemistry
  • Saliva / virology
  • Sunlight*
  • Vero Cells


  • Aerosols
  • Culture Media