Coronavirus loses 90 percent of its ability to infect people within 20 minutes of becoming airborne – with most of the loss occurring within the first five minutes, according to the world's first simulations of how the virus survives in exhaled air.

The findings re-emphasise the importance of short-range Covid transmission, with physical distancing and mask-wearing likely to be the most effective means of preventing infection, reports The Guardian.
Ventilation, though still worthwhile, is likely to have a lesser impact.

"People have been focused on poorly ventilated spaces and thinking about airborne transmission over metres or across a room. I'm not saying that doesn't happen, but I think still the greatest risk of exposure is when you're close to someone," The Guardian quotes Prof Jonathan Reid, director of the University of Bristol's Aerosol Research Centre and the study's lead author, as saying.
"When you move further away, not only is the aerosol diluted down, there's also less infectious virus because the virus has lost infectivity [as a result of time]," she added.