Wearing a used mask could be more dangerous than not wearing one when avoiding COVID-19, according to a new study.
A new three-layer surgical mask is 65% effective at filtering particles into the air, but when used, that number drops to 25%, according to the study published Tuesday in the journal Physics of Fluids.
Researchers at the University of Massachusetts Lowell and Baptist University in California say masks slow down airflow, making people more susceptible to particulate respiration and a dirty mask not being able to effectively filter out more drops. small.
“It’s natural to think that wearing a mask, whether new or old, should always be better than nothing,” said author Jinxiang Xi.
“Our results show that this belief is only true for particles larger than 5 micrometers, but not for fine particles smaller than 2.5 micrometers.”
To achieve their findings, the researchers used a computer model of a person wearing a pleated three-layer surgical mask to track how the covering face affected airflow and how particles passed. They also observed how the small drops landed on the face, airways, and where they landed in the nose, pharynx, or deep lung.
They found that wearing a mask “significantly decreases” airflow, reducing the effectiveness of the mask and making a person more susceptible to inhaling aerosols in the nose, where SARS-CoV-2 likes to ambush. -se.
“In this study, we found that the protective effectiveness of a mask for the nasal airways decreases at lower inhalation flow rates,” the study said.
The folds of a face mask also significantly affect airflow patterns and their effectiveness changes with increased use, the researchers found. The team plans to study how the shapes of the masks affect protection against COVID-19.
“We hope that public health authorities will strengthen the current preventive measures to curb the transmission of COVID-19, such as choosing a more effective mask, wearing it properly for maximum protection and avoiding the use of an excessively used surgical mask. or expired, ”Xi said.