Open your windows while eating a Christmas dinner: simulation reveals how fresh air sucks coronavirus particles in a dining room
- Hexagon Manufacturing Intelligence experts in Japan made the simulation
- Looked at what happens to particles expelled from the mouth of an infected person
- Reveals that opening windows and doors to improve ventilation and significantly affects the number of infectious particles in the room
A shocking new video reveals the risks people take by having a Christmas dinner with someone who lives in another household.
It shows how in a typical British dining room, coronavirus particles expelled from a person’s mouth circulate and infect other people.
Hexagon Manufacturing Intelligence experts in Japan built a model to demonstrate the level of risk that an asymptomatic person poses to other people at a table.
The engineers hope their simulation can help individuals and families estimate the risk of mixing during the holiday season.

Working on room dimensions of 4.9mx 3.7m (16ft x 12ft), the researchers ran two versions of their simulation, with the room closed off without ventilation (left) and another with two windows and a door open, each for ten minutes (turn right)
The researchers worked on room dimensions of 4.9mx 3.7m (16ft x 12ft) and ran two versions of their simulation, one with the room closed with no ventilation and another with two windows and a door open, each for ten minutes .
In the videos, the researchers map the particles expelled from a person’s mouth during regular breathing and talking.
This causes a relatively pedestrian dispersion of particles compared to a cough or sneeze.
“ Engineers at Hexagon in Japan have created the simulation as part of a public education effort to help authorities and the general public understand how best to protect themselves and each other from COVID-19 transmission, ” said Keith Perrin, Industry Director for Hexagon v MailOnline.
“Being Japanese, they were used to social aloofness and wore PPE when sick, so they were intrigued by different attitudes.”
Heat from radiators, food, and people sitting around a dining table forces particles towards the ceiling, but if there is insufficient ventilation they have nowhere to escape and are forced to return and swirl around the room.
However, if there is adequate ventilation through open windows, the particles will be sucked out almost immediately and away from other people.
“Good ventilation is essential – just make sure that as many windows and doors as possible are open to allow air to circulate and the particles not to accumulate,” said Mr. Perrin.


In the videos, the researchers map the particles expelled from a person’s mouth during regular breathing and talking. This causes a relatively pedestrian dispersion of particles compared to a cough or sneeze


Heat from radiators, food, and people sitting around a dining table forces particles towards the ceiling, but if there is insufficient ventilation they have nowhere to escape and are forced to return and swirl around the room


If there is adequate ventilation through open windows, infectious particles are almost immediately sucked out and away from other people
Social distance is important regardless of the ventilation in the room, but it is not safe – the unventilated simulation shows that the number of infected particles accumulate and travel beyond the recommended distance minimum of 2 meters, so it is very bad to get air in. get to the room. important to maximize the effectiveness of social distancing.
“At the end of the segment, however, there are some elements that compare the effect of an open window.”
He reveals that based on their calculations, an infected person in an unventilated room would infect six more people.
Statistically, however, in a ventilated average dining room, no one else would be infected.
This simple effort results in a significant statistical change.
“To give you an idea, over the course of three transmission iterations, assuming comparable circumstances, that mathematically would be 215 infected people less!” he says.
“Our studies show that it is not a matter of” whether “transmission will occur, but” when. “
Hexagon’s team used their expertise during the pandemic to show people how invisible droplets and aerosols can spread without people knowing.
One of their videos shows how suppressing a sneeze with an elbow is better than not stopping at all, but can still put people nearby at risk.
Another visualization showed what can happen if a person does not wear a mask on the tube or train.