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Wearing This Mask Could Be Worse Than No Mask, Says Study

If a mask is dirty, it can’t filter out those tiny droplets.
FACT CHECKED BY Alek Korab
Woman wearing anti virus protection mask

Wearing a face mask is one of the fundamental tools we have in preventing the spread of COVID-19. Over the last year, researchers have been studying protective face coverings, attempting to fully understand which are most effective in filtering out virus particles, examining both medical grade masks as well as cloth. Now a new study warns that there is one type of mask that might be less effective than keeping the virus at bay then wearing no mask at all: a used mask. Read on to hear why, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus

Never Wear a Used Mask, Says Study

A study published Tuesday in the Physics of Fluids conducted by researchers from the University of Massachusetts Lowell and California Baptist University found that the average three-layer surgical mask is 65 percent efficient in filtering particles in the air—when it is new at least. Once it has been used and reworn, the number drops to 25 percent. They believe it has to do with the fact that masks slow down airflow, which can make people more susceptible to breathing in particles. If a mask is dirty, it can't filter out those tiny droplets. 

"It is natural to think that wearing a mask, no matter new or old, should always be better than nothing. 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," author Jinxiang Xi explained in an accompanying press release

Using a computer modeling system, they examined how the three-layer surgical mask affected airflow and how particles passed through. Additionally they looked at how and where they landed on the face and inside the nose, pharynx or deep lung.

While wearing a mask "significantly slows down" airflow, they "found that the protective efficacy of a mask for the nasal airway decreases at lower inhalation flow rates," per the study. 

They hope their findings will encourage health officials to look into more effective strategies for mask wearing. 

"We hope public health authorities strengthen the current preventative measures to curb COVID-19 transmission, like choosing a more effective mask, wearing it properly for the highest protection, and avoid using an excessively used or expired surgical mask," said Xi.

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How to Survive This Pandemic

As for yourself, follow the fundamentals and help end this surge, no matter where you live—wear a clean face mask, social distance, avoid large crowds, don't go indoors with people you're not sheltering with (especially in bars), practice good hand hygiene and to protect your life and the lives of others, and don't visit any of these 35 Places You're Most Likely to Catch COVID.