Transport and evaporation of virus-containing droplets exhaled by men and women in typical cough events

TL;DR

This study uses high-resolution simulations to compare how male and female exhaled droplets behave during coughing, revealing gender-related differences in droplet spread and evaporation that impact infection transmission.

Contribution

It provides the first detailed numerical analysis of how gender-specific airflow profiles influence droplet dispersion and evaporation during coughs.

Findings

Male and female coughs produce different droplet dispersion patterns.

Gender influences droplet evaporation time and final reach.

Results highlight the importance of considering physical exhalation differences in infection control.

Abstract

The spreading of the virus-containing droplets exhaled during respiratory events, e.g., cough, is an issue of paramount importance for the prevention of many infections such as COVID-19. According to the scientific literature, remarkable differences can be ascribed to several parameters that govern such complex and multiphysical problem. Among these, a particular influence appears associated with the different airflows typical of male and female subjects. Focusing on a typical cough event, we investigate this aspect by means of highly-resolved direct numerical simulations of the turbulent airflow in combination with a comprehensive Lagrangian particle tracking model for the droplet motion and evaporation. We observe and quantify major differences between the case of male and female subjects, both in terms of the droplet final reach and evaporation time. Our results can be associated with the different characteristics in the released airflow and thus confirm the influence of the subject gender (or other physical properties providing different exhalation profiles) on both short-range and long-range airborne transmission.