How does an microdroplet cloud move and dissipate?
Inside vs Outside - What's the difference?
What is so special about outside air? Let's consider some familiar settings:
Outside is the Current Buzz Word
The now familiar comments by Dr. Fauci And other public health officials about social distancing and using a mask to avoid virus transmission has started to evolve. Since mid July "Open the window to get some fresh air" has become a common message from public health and others.
So we are now hearing how opening the window is helpful to improve safety against Covid transmission. It seems like a simple message and quite a logical one
That short phrase “open the window to air out the place” is actually describing the value of ventilation (ie air movement) through the building.
This ventilation moves clean air in while moving air out of the building which may contain floating virus particles.
Once outside, the virus particle concentration becomes so dilute so as to be negligible and therefore no longer a concern for the virus transmission to other humans breathing the air .
The following clips from Japanese researchers helps us understand the way airborne particles become trapped indoors and the impact of ventilation.
The following graphics show six people gathering in an enclosed space for multiple hours.
After four hours together without wearing masks, five others will be infected by patient 0, even if safe distances were maintained.
Even when face mask are worn, four people are infected from the prolonged exposure in a poorly ventilated area.
When the area is ventilated, everyone wears face masks, and the duration of the gathering is cut in half, then the risk of infection drops to below one.