A new public health campaign has been launched to "stop COVID-19 hanging around" in the run up to Christmas.
With people spending more time socialising indoors in winter months, the campaign encourages people to open windows for 10 minutes each hour, highlighting the importance of ventilation.
An explainer film, to be used on NHS and government digital channels, has been released by scientists from the Universities of Cambridge and Leeds and shows the difference in airflow and airborne particle movement.
Voiced by Dr Helen Lawal, the film shows how someone infected with the virus talking and interacting in an unventilated room produces a build-up of COVID-19 particles.
Particles linger, which means the risk of catching the virus is significantly increased.
But the COVID-19 particles disperse quickly with good ventilation.
Dr Thomas Waite, deputy chief medical officer for England, said: "Small but important actions can help protect us against COVID-19. Getting vaccinations, wearing a face covering in enclosed spaces and taking regular COVID-19 tests all make an important difference but it is also 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.
"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."
It comes as new research found 64% of people do not know ventilation is an effective way to reduce the spread of COVID-19 at home.
Only 29% of people currently ventilate their home when they have visitors over and only 3% of those surveyed continue to ventilate their homes for a period after guests have left.
Professor Catherine Noakes, professor of environmental engineering at Leeds University, added: "As winter approaches, people will naturally spend more time indoors, welcoming friends and family into their home as the weather gets colder.
"While we've all been looking forward to this for so long, it's important to remember that coronavirus is still around us and can easily spread in the home."
The advice is also to keep taking free lateral flow tests on a regular basis, particularly before mixing in crowded indoor spaces or visiting vulnerable people.