In
an open letter to the German government and state premiers, five leading members of the Association for Aerosol Research (GAeF) write that "The transmission of SARS-CoV-2 viruses takes place indoors almost without exception. Transmission outdoors is extremely rare and never leads to cluster infections as can be observed indoors."
The researchers observe that aerosols linger for much longer in confined spaces. "Wearing a mask in a pedestrian zone and then sitting at home having a coffee with friends is not our understanding of effectively preventing infections," the letter goes on to say.
The Robert-Koch-Institute (RKI), which also monitors and evaluates the provenance of infection hotspots, did not respond to a DW request for a comment on the letter. However, the RKI points out that the debate should not focus merely on the risk of infection outside in parks or pedestrian zones — but also the journey there, for example by bus or train. Nevertheless, in its
coronavirus profile, the RKI also posits that "overall, transmissions outdoors rarely occur. If the minimum distance is maintained, the probability of transmission outdoors is very low due to the flow of air."