New guidelines released on Friday from the US Centre for Disease Control suggests that fine droplets spreading Covid can remain suspended in the air for hours.
According to a scientific brief, the top medical body found that very fine aerosolised particles released during respiration was the SARS-CoV-2 virus’ main method of infection.
It found that very fine droplets, along with aerosol particles formed when these droplets dry rapidly, are small enough to remain suspended in the air for minutes to hours.
"People release respiratory fluids during exhalation (quiet breathing, speaking, singing, exercise, coughing, sneezing) in the form of droplets across a spectrum of sizes. These droplets carry the virus and transmit infection," said the CDC, explaining that the risk of transmission was greatest within three to six feet of the source.
"These transmission events have involved the presence of an infectious person exhaling virus indoors for an extended time (more than 15 minutes and in some cases hours) leading to virus concentrations in the air space sufficient to transmit infections to people more than 6 feet away, and in some cases to people who have passed through that space soon after the infectious person left," it was added.
The medical body asserted that existing measures, such as hand washing, social distancing, mask-wearing, regular sanitisation, proper ventilation and avoiding crowded indoor spaces were still effective against the virus.