Face masks can drastically blunt the spread of Covid by halving how far contagious particles can travel, a study suggests.
University of Central Florida researchers found droplets emitted by infected people when they speak can float in the air for 4ft. Coughing propels them even further, to around 4.5ft.
But the particles, which can carry Covid, only travel around 2ft when people wear cloth masks.
Triple-layer disposable masks worked even better, cutting the distance travelled by the droplets to just 0.5ft.
Experts argued the findings offered proof that stringent social distancing guidelines could safely be relaxed, as long as masks are worn.
The World Health Organization still recommends people stay 3ft apart in public spaces, and avoid crowds and large gatherings.
The above shows the distance travelled by droplets from someone when they spoke or coughed for five minutes while un-masked, wearing a cloth mask, or wearing a disposable mask. Standard disposable masks have three layers
England did away with its controversial ‘one metre plus’ rule last year, but No10 still recommends people avoid close contact with anyone they don’t live with.
In Scotland, ‘one metre’ social distancing is required in pubs, bars and restaurants, and in Wales ‘two metre’ distancing is in place in public spaces.
The US also still has social distancing up to 6ft in places — but it has said children wearing masks in schools only need to keep a 3ft distance.
Evidence on how Covid spreads has shifted since the pandemic began.
Policymakers originally urged people to wash their hands because it was feared the virus spread through touching contaminated surfaces.
But an array of studies have since suggested that the pathogen actually transmits primarily through the air.
Covid may linger in bathrooms for 20 minutes, study shows
Covid may linger and remain infectious in shower and steam rooms for at least 20 minutes after an infected person has left, a study suggests.
Bristol University researchers found that the SARS-CoV-2 virus thrives in humid or damp environments.
Until now, studies into how infectious the coronavirus is in various settings relied on an imprecise method that involved spraying viral particles into sealed drums.
But they didn’t accurately replicate the nuances that occur when an infected person coughs, sneezes or breathes in a real-world environment.
Now scientists have developed what is thought to be the most accurate method of monitoring this process.
They found that as the virus particles leaves the moist conditions of the lungs and become airborne they quickly dry out.
But at 90 per cent humidity – the equivalent of a steam or shower room – half of particles were still infectious after five minutes.
At 20 minutes, around 10 per cent of the virus remained infectious.
Like for other respiratory diseases, Covid sufferers emit tiny virus-laden droplets when they breath, speak or sing.
Once these are suspended in the air, they can then be taken in by another person — allowing the infection to spread.
Scientists asked 14 participants — aged in their twenties and thirties — to recite a phrase and cough for five minutes.
It is thought that none of the participants had Covid when they took the test, although it is not clear how the results would change with an infected person.
They were asked to do the experiment under three scenarios, according to the study published in the Journal of Infectious Diseases.
Specialist machines tracked how far the droplets travelled from the individuals in all directions.
Professor Kareem Ahmed, study author, said: ‘The research provides clear evidence that 3ft of distancing with face coverings is better than 6ft of distancing without.’
Office for National Statistics surveys suggest 96 per cent of Britons wear face masks when they leave their home. And 91 per cent wear them while shopping.
In the US, polling suggests that the vast majority of people also wear face masks in public spaces.
Studies originally painted doubts over face masks, with some studies showing they had a huge impact on infection rates while others showed they had virtually none.
But evidence has since shown benefits of the coverings, which are able to block up to 80 per cent of virus-laden particles into the air.
It comes after a study by Bristol University found Covid may linger and remain infectious in shower and steam rooms for at least 20 minutes after an infected person has left.