Man wearing surgical mask

Aerosol Particle Escape

Angie Szumlinski Studies

In a recent article published in Scientific Reports, there was a discussion regarding the use of surgical masks to reduce the emission of expiratory particles produced via breathing, talking, coughing, or sneezing. Two factors play a primary role in determining the overall particle reduction efficiency of a given mask type: the material filtering efficiency, which depends on the particle size, and the mask fit, which determines the fraction of air inhaled or exhaled air that passes through the mask versus around the sides of the mask.

In this study, the effectiveness of surgical masks was examined to identify if they reduce emission of expiratory particles. The findings were that air escaping out of the mask tope (the nose area) carries the most particles and provides the smallest reduction compared to no mask-wearing. Air escaping out the sides leads to a somewhat greater reduction in particles compared to air that escapes at the top.

As a key conclusion, the results strongly corroborate the efficacy of surgical masks at significantly reducing emission of expiratory particles into the surrounding air, despite the existence of non-filtered leakage flows around the sides of the mask. Without a mask, the expiratory airflow will travel directly away from the talker or cougher in a high-velocity plume towards others who may be nearby. Believe it or not, masks do work. If you are in a situation where you aren’t sure about your personal safety please continue to mask up! Stay well, stay informed, and stay tuned!