People are being urged to regularly open windows while socialising with others at home in order to prevent the spread of Covid.
A government-back campaign has been launched to show the importance of good ventilation in the fight against the virus, as the pandemic enters its second winter.
The public will be told opening a window for 10 minutes every hour when socialising indoors can help tackle the spread of Covid.
This message will be put across in an explainer film, that will be shared on NHS and government online channels.
The video will show how someone with Covid, who is talking with another person at home, produces a build-up of virus particles in the air.
These particles linger in an unventilated room, increasing the risk of catching Covid.
The video will explain good ventilation, even if just for a short time, can help Covid particles to disperse quickly.
“Small but important actions can help protect us against Covid-19,” Dr Thomas Waite, the deputy chief medical officer for England, said.
He said while vaccines, wearing face coverings in enclosed spaces and regular tests were important, it was “crucial that we don’t overlook the value of ventilation”.
“People with Covid-19 release virus particles into the air whenever they speak, breathe or cough and these can linger in unventilated settings,” Dr Waite said.
“With winter fast approaching and people spending more time indoors, it’s vital everyone understands the importance of using ventilation, such as regularly opening windows - even if just for a few minutes - to keep the air moving and prevent infections.”
The government also put out a message last year telling the public to open windows to improve ventilation and reduce the risk of catching Covid in winter.
The latest campaign comes after research showed nearly two thirds of the public did not know ventilation was an effective way to prevent Covid from spreading at home, the government said.
Earlier this week, Jonathan Van-Tam, another deputy chief medical officer for England, warned the UK’s high Covid rates and rising deaths mean there are “hard months to come” this winter.
