According to HPC Wire, 30 researchers from various institutions used a supercomputer to model a space with aisles between shelves to simulate a typical grocery store. Then, they introduced human figures in different aisles and had one couch, spraying a cloud of aerosol particles smaller than 20 micrometers in front of them.
The model shows how particles from a cough move across the simulated space of a grocery store, and demonstrate how one could be infected several minutes after the cough. Super freaky!