DIY masks to protect against from viruses sounds like a crazy idea. Data shows masks work incredibly well, and they’re also really cheap. Surgical masks cost a few pennies, and they’re capable of filtering out 80% of particles down to 0.007 microns (14 times smaller than the coronavirus).
However, the coronavirus outbreak brought with it a new problem: masks are sold out.
People have scrambled to make their own masks, but can homemade masks really protect you from the coronavirus? Smart Air has analyzed the data to give you the answer.
Testing DIY Masks
Scientists from the University of Cambridge asked this exact question in the aftermath of the 2009 H1N1 flu pandemic. They thought that in a global pandemic scenario, we might run out of N95 masks. Their predictions have come true during the coronavirus outbreak.
The researchers asked volunteers to make their own masks using cotton t-shirts and a sewing machine, using a simple protocol they’d devised. Next, they performed a fit test to test how well they could capture particles down to 0.02 microns. They compared the DIY masks against surgical masks.
The homemade cotton masks captured 50% of 0.02-1 micron particles, compared with 80% for the surgical mask. Although the surgical masks captured 30% more particles, the cotton masks did surprisingly well. The researchers concluded that homemade masks would be better than nothing.
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Is that the only test on DIY masks?
The Cambridge data shows that homemade masks made using cotton t-shirts can filter out some particles that are 0.02–1 microns in size. That’s pretty good, however its only one test. Is there any more data for other DIY masks available? A group of researchers in the Netherlands tested homemade masks made from a tea cloth for smaller particles, that are more similar in size to viruses.
They tested what percentage of particles the masks could capture for the same sized particles as the Cambridge researchers: from 0.02 to 1 micron. They also used a fit-test machine to test the masks while people were actually wearing them.
The tea cloth mask captured 60% of the 0.02 – 1 micron particles. Not surprisingly, the surgical mask and N95 mask captured more particles, but the data shows homemade mask was far from useless at capturing virus-sized particles.
How Long Can You Wear DIY Masks for?
Next, they tested the DIY masks’ effectiveness after people had worn them for 3 hours. The results showed that moisture and time had very little impact on effectiveness for any of the masks.
In fact, the homemade masks actually captured 5.8% more virus-sized particles after 3 hours. Thus, wearing them for several hours seems to have little impact on their effectiveness.
Do Homemade Masks Work for Children?
Next, they tested homemade masks with 11 children 5 to 11 years old. When kids wore the homemade masks, they removed just 52% of the 0.02 – 1 micron particles. That means the masks were roughly 15% less effective on kids than on adults.
Interestingly, the surgical masks and FFP2 (N92) masks also did worse on children. This fits with a Smart Air test of children’s masks in India that found lower effectiveness on children than adults. The data suggests that it is harder to fit masks on children’s faces.
Bottom Line on DIY Masks for Fighting Viruses
Data shows that DIY masks made with a single layer of cotton clothing or a tea towel can remove around 50-60% of virus-sized particles. This means they perform worse than surgical masks and FFP2 (N95) masks. Wearing the homemade masks for 3 hours had no significant effect on the filtration efficiency.
DIY masks also work for children, but they are less effective on kids than they are on adults.
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Paddy is the CEO of Smart Air, running operations from Beijing. He’s has a Masters in aeronautical engineering from Bristol University, UK having specialised in aerodynamics. An advocate for open data, free information and transparent business, he spends his spare time promoting honest business and social enterprise.