University of California, Irvine team aims to determine best do-it-yourself protective coverings, finding bandanas more or less useless.
The air that pours into your lungs when you breathe travels, on average, at about 10 centimeters a second. But it’s often not just air you’re breathing. There can be dust, pollen, soot and bacteria in air, and now, floating inside the droplets that people emit when they cough and sneeze and talk, there can be the coronavirus.
“Even as much as singing and talking apparently have the capability of generating small particles that can be used as carriers for this virus,” says James Smith, UCI professor of chemistry, an aerosol expert who studies how things like dust and water droplets behave in the air.
Medical masks, he explains, can help stop these droplets. But with masks in such short supply that people are sewing their own, and with a raft of do-it-yourself mask-making videos emerging online, a team of UCI researchers led by Smith assembled to figure out how to make masks that are safe to use and that anyone can craft at home. They’ve already discovered that “things like bandanas – a common item people might use as a mask – are only effective at stopping the kinds of large droplets emitted when someone sneezes,” Smith says.
“Every day, I open up the news and I see another story about masks, about homemade masks, and about filtration in general, and I see a lot of misinformation about it,” he says. His team will post more findings alongside mask-making instructions on a new website.
The researchers applied for funding from the university but are getting to work before it arrives. “We couldn’t wait,” says Smith, whose aim is to use what he knows about aerosols to test how effective different kinds of household materials are at filtering out airborne particles like virus-laden water droplets. “I was so anxious to throw my hat in the ring. I was keen to see if I could make some kind of difference.”
Now, in his lab in the basement of Rowland Hall, there are two figures: Smith and what appears to be a man’s head locked inside a Plexiglas box. It’s the head of a mannequin, delivered last week by co-investigator Michael Kleinman, UCI adjunct professor of medicine. Smith is using it to simulate air flowing through the mannequin’s nose at the same average speed that we inhale air – about 10 centimeters a second. He straps everyday household fabrics such as furnace filters, bedsheets, pillowcases and bandanas to the mannequin’s face and, after fitting a breathing tube into the mannequin’s throat, injects particles into the box and measures the efficiency with which each material filters them. Smith employs a mannequin so he can mimic how air flows into the nose and to make sure the masks that he and his team devise will actually fit around a human face.
So far, they’ve tested more than 50 kinds of fabric. “What we’re trying to do is develop a simple-to-build mask that does a really good job of filtering,” Smith says. “Our best luck has actually been using a furnace filter made of nonwoven polypropylene that I pulled out of my garage and cut up.”
He cautions that not all fabrics found around the house are good options for a face mask. Some materials, including furnace filters made of Fiberglas, can send fibers into a person’s lungs. “We want people to understand what is effective and what is not,” Smith says. “We feel that in the next week we’ll have a design available.”
what about vaccuum bags???
That’s an interesting idea 🧐
Cloth Shower curtain
Please confirm that non woven Pellon interfacing is good. I use two layers of Pellon featherweight 911 F
What about top of the line HEPA air duct filtration fabric? Pkg says it removes dust, and air contaminates including bacteria and viruses…
Well written article and great research. The key piece is that everyone needs to wear them since they mostly protect the person not wearing them. Also a bit of humor and seriousness about shaving before you wear them here. https://thefutureprepared.com/best-mask-to-keep-virus-out/
Whenever I see bandanas recommended, the demonstration shows the bandana being folded so the result is 5 layers thick. Are the experts taking that into account when they say bandanas are useless? Five layers seem awfully thick to me.
4 layers of bandana and a paper tiwel inbetween is insufficient? Not enough details on the testing criteria
I’m using outer layer of 600 thread count Egyptian cotton sheets with a layer of non woven interfacing and a layer of cotton quilt batting sandwiched in between. The sheets are soft and kinder to your skin.Heres a thought… Silk! Its tightly woven and hypoallergenic,dust mites and other microbes won’t live in it!
Using bandanaa as face masks are helpful just as long as it is properly made. Added lining such as a coffee filter-unbleached does help. The use of a bandana are good for people who don’t know to sew, cost effective and easy to make, and for peopke who cannot afford to buy a face mask. Just having a face mask available is better than none at all. Thank you.
For some reason I can’t breathe with a face mask last time I had a panic attack because I couldn’t breathe with the mask my job provided it feels like the material is polyester it was getting to hot . freaking annoying someone please tell me which fabrics are the best for a mask and not get too hot .thank you
Huge difference in how a bandana is worn that I don’t see mentioned, that being just a triangle hanging loose in front of face totally vented to the atmosphere, vs tucking the “V” shape into shirt collar thereby giving total air seal all around.
Also, a pad of folded fabric or foam on nose to fill in and seal off the “eyeglass fog” leaks.
Also with bandana, MUCH larger surface area to filter through, less resistance, much greater filtering.