Close proximity risk assessment for SARS-CoV-2 infection

G. Cortellessa, L. Stabile, F. Arpino, D. E. Faleiros, W. van den Bos, L. Morawska, G. Buonanno*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

56 Citations (Scopus)


Although the interpersonal distance represents an important parameter affecting the risk of infection due to respiratory viruses, the mechanism of exposure to exhaled droplets remains insufficiently characterized. In this study, an integrated risk assessment is presented for SARS-CoV-2 close proximity exposure between a speaking infectious subject and a susceptible subject. It is based on a three-dimensional transient numerical model for the description of exhaled droplet spread once emitted by a speaking person, coupled with a recently proposed SARS-CoV-2 emission approach. Particle image velocimetry measurements were conducted to validate the numerical model. The contribution of the large droplets to the risk is barely noticeable only for distances well below 0.6 m, whereas it drops to zero for greater distances where it depends only on airborne droplets. In particular, for short exposures (10 s) a minimum safety distance of 0.75 m should be maintained to lower the risk below 0.1%; for exposures of 1 and 15 min this distance increases to about 1.1 and 1.5 m, respectively. Based on the interpersonal distances across countries reported as a function of interacting individuals, cultural differences, and environmental and sociopsychological factors, the approach presented here revealed that, in addition to intimate and personal distances, particular attention must be paid to exposures longer than 1 min within social distances (of about 1 m).

Original languageEnglish
Article number148749
Number of pages12
JournalScience of the Total Environment
Publication statusPublished - 2021


  • CFD analysis
  • Close proximity
  • Droplets
  • PIV
  • SARS-CoV-2
  • Virus transmission


Dive into the research topics of 'Close proximity risk assessment for SARS-CoV-2 infection'. Together they form a unique fingerprint.

Cite this