People are being urged to keep windows open in winter to reduce their risk of catching coronavirus.
The Department of Health has released a video illustrating how airborne coronavirus particles linger in spaces without ventilation.
Letting fresh air into indoor spaces can reduce the risk of infection from coronavirus by over 70%.
Experts recommend people either open windows fully for 10-to-15-minute periods regularly throughout the day or leave windows slightly open continuously.
Ensuring kitchen and bathroom extractor fans are regularly switched on can also help ventilate an indoor space.
Coronavirus is spread through the air by droplets and smaller particles, known as aerosols, that are exhaled from the nose and mouth of an infected person as they breathe, speak or cough.
They behave in a similar way to smoke, and the majority of virus transmissions happen indoors.
Without ventilation, the particles can remain suspended in the air for hours and build up over time.
Airing indoor spaces is particularly recommended when members of a bubble or tradespeople visit the home, and when someone in the household has the virus.
The new film, created with scientists and an engineer at Leeds University, will run across social and digital advertising in England.
It forms part of the Government’s wider ‘hands, face, space’ guidance.
Public Health Minister Jo Churchill said ventilation is ‘essential’ over winter.
She said: ‘As the weather gets colder and wetter, letting in fresh air in short burst helps to reduce the risk of coronavirus in our homes.
‘We should all remember: open your windows, and ‘hands, face, space’.’
Professor Catherine Noakes, from Leeds University who advised on the film, said: ‘When a room does not have any fresh air, and where people are generating large amounts of aerosol through activities such as singing and loud speech, that is when transmission of coronavirus is most likely.
‘Fresh air must come from outdoors – recirculating air just means the aerosols containing the virus move around the same room rather than being extracted outdoors.
‘Ventilation units or any household systems that use outdoor air can be just as effective as opening windows or doors as long as they are limiting the recirculation of the same air.’