Physics of Fluids publishes new study quantifying face mask effectiveness during coughing

Journal Brief

A study published this month in Physics of Fluids presents fluid dynamics research on respiratory droplet travel through and around face masks.¹ Using computer modeling, the study's authors evaluated respiratory droplet transmission during mild coughing. The masks tested were of an "air-permeable filtering material made of porous fibrous layers."

The study, titled, "On Respiratory Droplets and Face Masks," found that wearing a face mask significantly reduced droplet clouds, and that face masks generally cut the farthest distance traveled by respiratory droplets by half (to approximately 35 cm or 14 inches). However, vulnerabilities of masks—both through sideways leakage and through the mask itself—were found to be more complex than previously thought. A spell of ten coughs was found to reduce the effectiveness of a mask by approximately 8%.

The authors drew a number of conclusions relevant to health-care providers. Among their recommendations were for manufacturers and regulatory authorities to "consider new criteria for assessing mask performance to account for the flow physics and cough dynamics."

The authors noted that masks remained an important tool during the COVID-19 pandemic in conjunction with social distancing, with masks serving as a way of limiting the distance of droplet flow and blocking incoming droplets. 

Read the full study here.

Reference

1. Dbouk T, Drikakis D. On respiratory droplets and face masks. Physics of Fluids. 2020;32(6). doi.org/10.1063/5.0015044