It's a good point about other forms of transmission, but I think the air alone is an interesting question. What would be the limiting factor on how far it can

It's a good point about other forms of transmission, but I think the air alone is an interesting question. What would be the limiting factor on how far it can spread? Do the particles deactivate after a while in the air? Or is it that the concentration is not high enough? Latter case, wind patterns would matter a lot. Surely, when authorities talk about diseases being able to spread x many feet, it ignores many factors and is meant to be an actionable simplification that works in a statistical sense.