Ask the experts
How long can the coronavirus stay airborne? I have read different estimates. How long can the coronavirus that causes COVID-19 survive on surfaces? What do I need to do to disinfect my home?
In general, the coronavirus doesn’t stay airborne for a long period of time. Gravity does a good job of pulling down the infected droplets of saliva from people coughing, usually within minutes.
For example, the number of viable COVID-19 virus particles in an aerosol drops by half after about three hours, with the biggest drops in infectious viral numbers at roughly the one-hour mark, according to a March 17 study in the New England Journal of Medicine comparing the Wuhan coronavirus to the similar one that caused the 2003 SARS outbreak.
- In outdoor conditions, this risk of contracting COVID-19 from aerosols is smaller if you maintain your six feet of social distancing.
- You can still get infected if someone sprays on you; for instance, sneezes in your face or on your hands.
- Different weather conditions affect this, as well
It’s mainly person-to-person, so you are mainly going to pick it up through contact, but it can survive on surfaces. It survives a pretty long time on hard plastic and stainless steel, and it does a little bit worse on copper and cardboard, for example.
- The study showed a small number of virus particles could stay viable for up to 72 hours on hard plastic and stainless steel,
- Data show a steep drop in the viral numbers at 48 hours for both surfaces, however.
Viruses in infected saliva droplets or other secretions don't do as well on copper or cardboard.
- The virus can remain viable on copper surfaces for up to 8 to 10 hours.
- Virus particles are still measureable on cardboard surfaces after 24 hours.
Despite its long survival rate on some surfaces, the COVID-19 virus is easy to kill with standard disinfectants and cleaning practices.
- We’re just not sure how easy it is, and it depends on the disinfectant.
- Following the instructions on the disinfectant label is the best bet – some may say “let stand for two minutes,” for example.
- Instructions vary from compound to compound.
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van Doremalen N et al.
New England Journal of Medicine