From a compelling article by Professor of Chemisry Jose-Luis Jimenez on the argument that COVID is transmitted via aerosols:

The visual analogy of smoke can help guide our risk assessment and risk reduction strategies. One just has to imagine that others they encounter are all smoking, and the goal is to breathe as little smoke as possible.

When I’m in uncomfortably close proximity, I naturally hold my breath. It’s nice to know that’s not entirely insane.

I propose the following: Avoid Crowding, Indoors, low Ventilation, Close proximity, long Duration, Unmasked, Talking/singing/Yelling (“A CIViC DUTY”).

That’s a horribly difficult acronym to remember. But, the visual model of dealing with smoke drives home the required change in behaviour.

I’m happy that Ontario schools concentrated on ventilation and moving classes outside, even before the evidence was perfectly clear.

This model could turn out to be wrong, but the additional precautions don’t seem like a heavy burden against the potentially significant increase in safety.