On Interpersonal Distance, Time of a Conversation and Perceived Virus Exposure

Most COVID-19 infections are caused by airborne corona viruses. A model based on empirical and theoretical studies of dispersion of particles in the air was used to estimate a person’s virus exposures during different times and distances from a virus infected person. Participants judged perceived virus exposure at different interpersonal distances in a face to face conversation with an infected person. The smallest average face to face distance from an infected person without a mask that a participant judged as sufficiently safe was 13.5 meters. A majority (75%) of the participants underestimated the effect on virus exposure following a change of interpersonal distance. By way of contrast, judgments of exposure as a function of the duration of a conversation were unbiased. The results are important for administrators and communications to the general public about social distancing and infection risks.