As described in this web site’s sections “Saliva and mucous droplets” and “Aerosols,” larger droplets often fall from the air in one or two meters, and small aerosol particles can float for many meters.  So, the greater the distance you are from an infected person, the less likely that you will inhale many of their viruses (Anfinrud et al.; Asadi et al.; Bourouiba; Brosseau; Dhand, Li; Meselson; Tang, Li et al.; Stadnytskyi et al.).  A comparison of studies of the effects of physical distancing in household, community, and healthcare settings found that “at least 1 m physical distancing seem to be strongly associated with a large protective effect, and distances of 2 m could be more effective” (Chu et al.).