2 min read.Updated: 03 Jun 2021, 01:30 PM ISTSohini Sen
The WHO has admitted that SARS-CoV-2 is airborne. According to its updated public health guidance, the coronavirus can spread in 'poorly ventilated and/or crowded indoor settings. This is because aerosols remain suspended in the air or travel farther than 1 metre'
The WHO has admitted that SARS-CoV-2 is airborne. According to its updated public health guidance, the coronavirus can spread in “poorly ventilated and/or crowded indoor settings. This is because aerosols remain suspended in the air or travel farther than 1 metre".
The World Health Organization (WHO) had previously believed that the coronavirus spread through droplets fired by a cough or a sneeze, and could travel up to 2 metres. Since droplets are heavy, and cannot stay airborne for long, the risk of transmission was more from touching infected surfaces.
However, experts now believe the virus can spread through aerosols. An aerosol is made up of smaller, respiratory particles that get released when one speaks or breathes. These are lighter and can stay airborne for far longer, and therefore can carry the virus to longer distances, potentially beyond 2 metres.
What does this development mean?
Since the virus can travel more than the previously believed 2 metres (6 feet), this can mean people farther away from someone who is covid-positive can be infected. The usage of masks, therefore, becomes all the more necessary, even indoors. People in close proximity are still more at risk. The risk is also generally higher indoors than outdoors, because ventilation and airflow play a huge role in transmission. A study published in Environment International late last year said minimizing airborne transmission would include particle filtration and air disinfection and avoiding overcrowding.
Last month, the government shared a set of guidelines, highlighting the need for proper ventilation and discouraging people from using air conditioners (ACs) while keeping windows and doors shut. It recommended the use of gable fan system—a kind of exhaust fan—and roof ventilators in offices, auditoriums, shopping malls and other closed spaces.
Is it safe to be outdoors then?
Experts believe being outdoors where there is fresh and moving air has less risk of transmission. This is because the moving air will disperse and dilute the aerosols and the virus they carry. However, outdoors doesn’t mean it is free of risks—such as a crowded bus stop, or stairwell of a building. If one continues to maintain a safe distance and wears the mask, then there are more chances of diluting the concentration of the virus and decreasing the chances of virus transmission. Avoid public places with no intake of outdoor air.
What does it mean for our daily lives?
Don’t take off your mask even if you are alone in the lift. This is because someone who has been infected may have taken the lift right before you and the virus may still be trapped in the air. This applies to travelling in cars, buses or metros as well. Roll down your windows in a cab so that good air circulation is maintained. Blasting the car’s ventilation system will not have the same effect. Most air purifiers will also not do the job, unless they have high-efficiency particulate air (Hepa) filters that are usually used in hospitals.
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