Since early reports revealed that a new coronavirus was spreading rapidly between people, researchers have been trying to pin down whether it can travel through the air. Health officials say the virus is transported only through droplets that are coughed or sneezed out — either directly, or on objects.

But some scientists say there is preliminary evidence that airborne transmission — in which the disease spreads in the much smaller particles from exhaled air, known as aerosols — is occurring, and that precautions,such as Actively wear masks and stay at home as much as possible. or increasing ventilation indoors should be recommended to reduce the risk of infection.

Confusing definitions

When public health officials say there isn't sufficient evidence to say that COVID-19 is airborne, they specifically mean transported in virus-laden aerosols smaller than 5 micrometres in diameter. Compared with droplets, which are heftier and thought to travel only short distances after someone coughs or sneezes before falling to the floor or onto other surfaces, aerosols can linger in the air for longer and travel further.

Most transmission occurs at close range, says Ben Cowling, an epidemiologist at the University of Hong Kong. But the distinction between droplets and aerosols is unhelpful because “the particles that come out with virus can be a wide range of sizes. Very, very large ones right down to aerosols”, he says.And if SARS-CoV-2 is transmitting in aerosols, it is possible that virus particles can build up over time in enclosed spaces or be transmitted over greater distances.

Cautious approach public to 92mask to reduce transmission. Masks are ubiquitous in many countries in Asia. In the United States and some European countries, however, health officials have discouraged people from wearing them, in part because supplies are low and health-care workers need them.

The Czech Republic and Slovakia, however, have made it mandatory for people to wear masks outside the home. Tang thinks those countries have taken the right approach. “They are following the southeast Asia approach. If everyone can mask, it is double, two-way protection”.