Research Confirms That Masks Effectively Block Airborne Particles

Research confirms that outbound airborne particles from coughing or talking are effectively reduced with the use of surgical masks, even after taking into account leakage surrounding the mask edges. Using masks as well as other face coverings is effective in reducing the flow of particles that are airborne which are produced as a result of talking, breathing, sneezing or coughing, protecting other people from viruses transported by those particles like SARS-CoV2 and influenza.¹

High-efficacy masks like N95 respirators are made with having a tight seal on the face, whereas surgical and the majority of face masks made out of cloth leave small spaces around the edges, which may still be reduced if they’re worn properly.

Particles flowing from these spaces were examined by placing 12 participants facing a device that counts airborne particles as tiny as half a micron. They then coughed or read aloud, with and without the type surgical mask typically made use of, either with the mouth directly in front of the particle counter funnel, turned sideways or with the head lowered or elevated for counting particles that passed directly via the mask or leaked around the edges.

The researchers observed that particles passing directly through the mask were minimized by an average of 93% when using a mask, by 91% from the bottom of the mask, by 85% from the side of the mask and by 47% from the top of the mask, though with a substantial variation between participants. Similar results were observed for coughing.

Simulations were made use of for modeling the overall reduction in particles as a result of using a mask, taking into account edge leakage around. It was determined that the overall effectiveness of masks was approximately 90% for coughing and 70% for talking.

Although air escape does restrict the overall effectiveness of surgical masks at minimizing expiratory particle emissions, these masks nevertheless give significant reduction. The study results verify that mask wearing offers a considerable reduction in disease transmission probability via expiratory particles, particularly with both susceptible and infected individuals wearing masks. The flow from a high-velocity plume of air from the cougher or talker is also redirected away from any individual in front of them.