I raised this issue at work and this is what I was told: in order for viral particles to become airborne and capable of traveling through the air, they need to attach themselves to something (i.e, dust particles, respiratory droplets, mold spores, et etc), that has enough mass to be lifted by air currents, and viral particles are too small to travel through the air by themselves.
I’m still pondering the explanation that I was given.
I previously thought, perhaps erroneously, that getting sick had to do with the amount of viral particles to which one was exposed, and it wasn’t exposure per se that made one sick, but rather the amount of viral particles that one was exposed to, and respiratory droplets measuring 0.3 microns or larger contained enough viral particles to make one sick.
I am not a virologist or researcher, I’m just your average layperson, and I do not know the correct answer to these questions.