[newsclues]

Fluid mechanics are well understood.

There are people who understand how air moves, and have a good understanding of how viruses travel.

Masks have been hailed as a silver bullet (so that people don't have to get active and eat well and be healthy, and government and businesses don't have to upgrade HVAC systems), to the point where people think they work outside!

Are there masks that work? Yes. Is that cheap surgical mask or a cotton one really effective? No.