Since COVID-19 started, there has been confusion on how to correctly where a surgical mask. But does wearing surgical masks the wrong way round affect their ability to capture viruses?
Some online sources claim it doesn’t matter, like this one.
Surgical masks are made up of 3 layers, and there is a specific way to wear them: with the colored, rough-textured side out.
But does the direction you wear it actually affect its ability to capture viruses? Smart Air tested sub-micron particle capture to see whether the orientation of a surgical mask really affects performance.
WATCH: What is the Right Way Round to Wear a Surgical Face Mask
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Testing Surgical Mask Efficiency from Both Sides
To test the surgical masks, we used the same wind tunnel setup that was used for our homemade mask materials tests. In that setup, a fan on one side of a wind tunnel pushes air through the mask on the other end. There, a Met One GT-521 laser particle counter measures how many particles penetrate the mask.
We tested the blue side and white side of four surgical masks.
We measured what percentage of particles 0.3 microns and above they could capture. Although COVID-19 is 0.12 microns on average, scientists sampled air in hospitals and found that SARS-CoV-2 sometimes travels on aerosols from 0.25-0.50 microns.
Surgical Mask Blue vs. White Side Results
Across four masks, putting the mask in the correct direction improved particle capture by 1.7% on average. On one mask model, the improvement was nearly 3%.
Although these numbers are pretty small, wearing the mask the right way will increase its effectiveness at capturing virus-sized particles.
Remember: Rough Blue Side Out, Soft White Side In
This data backs up the claim that the colored side of surgical masks (typically blue or green) should face out. The softer white layer should face in.
How I Protect Myself
Along with wearing masks, air purifiers with HEPA filters are also one of the best ways to stay safe from a variety of pollutants in our air including viruses and dangerous PM2.5. A recent CDC study confirmed significantly lower COVID-19 infection rates in schools that used HEPA air purifiers.
Smart Air is a certified B Corp committed to combating the myths big companies use to artificially inflate the price of clean air.
Smart Air provides empirically backed, no-nonsense purifiers and masks, that use the same HEPA filters (that filter 95-99.5% of particles of size 0.3 microns) for a fraction of the cost of big companies.