It is lately believed that coronavirus is airborne, which means that it can be carried through the air in a viable form.
For the coronavirus specifically, the virus can not travel long distances. Still, it can traverse the length of a room, and recent experiments data show that the virus can remain viable as an aerosol for up to 3 hours.
Scientists have insisted for months that infected people are also releasing aerosols when they cough or sneeze and even when they breathe or talk. Now we have the answer to why people can spread the virus even in the absence of symptoms. Aerosols are the explanation for this phenomenon.
Until recently, however, the risk from these aerosols wasn’t taken into consideration.
The W.H.O. and other public health organizations insisted that the virus was primarily transmitted by coughing or sneezing droplets – larger particles that settle more quickly and are less likely to accumulate in the air. As they have only focused on the virus’s ability to spread through large droplets, the existence of aerosols as being a longer-term threat that can stay aloft in the stagnant air was excluded.
It took pressure from more than 200 scientists for the WHO to take the initiative. They published an open letter to the WHO calling for attention and guidance around aerosols as a route of transmission. They urged the organization to recognize the risks in airborne transmission of coronavirus via aerosols.
The WHO responded on July 9 with an update in which it acknowledged that airborne transmission could be partially accountable for the spread of the disease.
“The possibility of airborne transmission in public settings, especially in very specific conditions — crowded, closed, poorly ventilated settings — cannot be ruled out. However, the evidence needs to be gathered and interpreted,” said Dr. Benedetta Allegranzi, WHO’s technical lead for infection prevention and control.
Although they acknowledged the growing evidence, they can’t say for sure how much transmission aerosolized particles are responsible for versus droplets and contaminated surfaces.
Therefore, it is still unclear how often the virus is spread via these tiny droplets compared with larger droplets.
Aerosols contain much less virus than droplets do since they are smaller, but being lighter, they can remain in the air for a significant period of time, even more so in the absence of fresh air.
There is a major risk in crowded indoor spaces with poor ventilation where a single infected person can release enough aerosolized virus to cause super-spreading events by infecting a significant number of people.
For our safety, we are advised to consider minimizing time indoors with people outside our families. Public buildings should add powerful new air filters and ultraviolet lights that can kill airborne viruses. Also, we should never forget to wear masks!