Estimated Inactivation of Coronaviruses by Solar Radiation With Special Reference to COVID-19

Photochem Photobiol. 2020 Jul;96(4):731-737. doi: 10.1111/php.13293. Epub 2020 Jul 9.


Using a model developed for estimating solar inactivation of viruses of biodefense concerns, we calculated the expected inactivation of SARS-CoV-2 virus, cause of COVID-19 pandemic, by artificial UVC and by solar ultraviolet radiation in several cities of the world during different times of the year. The UV sensitivity estimated here for SARS-CoV-2 is compared with those reported for other ssRNA viruses, including influenza A virus. The results indicate that SARS-CoV-2 aerosolized from infected patients and deposited on surfaces could remain infectious outdoors for considerable time during the winter in many temperate-zone cities, with continued risk for re-aerosolization and human infection. Conversely, the presented data indicate that SARS-CoV-2 should be inactivated relatively fast (faster than influenza A) during summer in many populous cities of the world, indicating that sunlight should have a role in the occurrence, spread rate and duration of coronavirus pandemics.

MeSH terms

  • Aerosols / radiation effects
  • Air Microbiology
  • Betacoronavirus / radiation effects*
  • COVID-19
  • Coronavirus Infections / prevention & control*
  • Coronavirus Infections / transmission*
  • Coronavirus Infections / virology
  • Environmental Microbiology
  • Humans
  • Models, Biological
  • Pandemics / prevention & control*
  • Pneumonia, Viral / prevention & control*
  • Pneumonia, Viral / transmission*
  • Pneumonia, Viral / virology
  • Radiation Tolerance
  • SARS-CoV-2
  • Seasons
  • Solar Energy*
  • Sunlight*
  • Ultraviolet Rays
  • Virus Inactivation / radiation effects*
  • Weather


  • Aerosols