Singing is also likely to expel more droplets further. I don't have a source, but a microbiologist I know was saying that safe distances, based on droplet phys

Singing is also likely to expel more droplets further. I don't have a source, but a microbiologist I know was saying that safe distances, based on droplet physics, depend on activity, e.g. standing in a single file line vs walking vs hiking vs running.