I imagine there is some kind of exponential risk decay curve with distancing. If you are 100 feet away, your risk is near zero. At 6 feet, perhaps it is 3% or something. Exposure time would also be a factor of course, presuming the individual is contagious.
The sneeze/cough vector would be attenuated if said person was wearing some sort of facial covering. Avoid skin contact with anyone outside your family. Don't share needles.