This is kind of interesting. Check figure C.2. The behavior of droplets depends on size, but they all either evaporate or fall to the ground within 4.5 seconds. Knowing this has made me feel better about better about walking a dozen feet behind somebody outside.
If evaporation matters, then transmission rates should depend strongly upon humidity. However, there are studies saying transmission rates decrease with relative humidity. Maybe drying is irrelevant, or maybe there is another factor, or maybe the studies are wrong.
I distinctly remember reading recently that it's absolute, not relative, humidity that counts. The article did not give a reason, nor can I remember the source (sorry).
https://www.ncbi.nlm.nih.gov/books/NBK143281/