COVID-19 Is Transmitted Through Aerosols. We Need to Adapt | Time
We should continue doing what has already been recommended: wash hands, keep six feet apart, and so on. But that is not enough. A new, consistent and logical set of recommendations must emerge to reduce aerosol transmission. I propose the following: Avoid Crowding, Indoors, low Ventilation, Close proximity, long Duration, Unmasked, Talking/singing/Yelling (“A CIViC DUTY”). These are the important factors in mathematical models of aerosol transmission, and can also be simply understood as factors that impact how much “smoke” we would inhale.
A CIViC DUTY first suggests that we should do as many activities as possible outdoors, as schools did to avoid the spread of tuberculosis a century ago, despite harsh winters. Given how much being outside reduces COVID-19 transmission risk, it is mind boggling that the U.S. National Guard is not busy setting up open canopy tents at every school around the country. That said, stepping outdoors is not a magical protection against contagion: a windy day in an open area while keeping our distance is very safe, but an unmasked close conversation with still air in a narrow passage between tall buildings is risky.
Second, masks are essential, even when we are able to maintain social distance. We should also pay attention to fitting masks snugly, as they are not just a parapet against ballistic droplets, but also a means to prevent “smoke” from leaking in through gaps. We should not remove masks to talk, nor allow someone who is not wearing a mask to talk to us, because we exhale aerosols 10 times as much when talking compared to breathing. Everyone should be careful to not stand behind someone with a poorly fitting mask, as the curvature of an ill-fitting mask can cause aerosols to travel behind the person wearing it.