Can DIY Masks Protect Us from Coronavirus?

Can DIY masks filter out viruses and coronavirus

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.

N95 air pollution masks sold out due to coronavirus

People have scrambled to make their own masks, but can homemade masks really protect you from the coronavirus?

One Users' DIY air pollution anti-virus mask

One Person’s DIY ‘anti-virus’ mask

Can DIY Masks Capture Viruses?

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.

Efficacy of Homemade Masks Viruses Pandemic

The researchers asked volunteers to make their own masks using cotton t-shirts and a sewing machine, using a simple protocol they’d devised. Then the researchers shot tiny 1-micron size bacteria (called “Bacillus atrophaeus”) at the masks and measured what percentage the homemade masks could capture. These particles are roughly the size of the particles behind the plague and anthrax.

The DIY masks captured fewer particles than the surgical mask, but they still managed to capture 69% of 1-micron particles.

But is that the smallest particle homemade masks can capture? The researchers stepped it up a notch by shooting .02-micron “Bacteriophage MS2” particles at the masks. These are even smaller than coronavirus particles.

DIY Mask vs 0.023 Micron Particles at capturing viruses covid

Again, the surgical mask captured more particles, but the homemade cloth mask captured 51% of these nanoparticles.

OK, But They’re Leaky, Right?

At this point, smart skeptical readers are probably thinking, “sure, cloth can capture particles, but they probably don’t seal around the face, so they’re ineffective.”

Fortunately the researchers fit-tested the DIY masks too. In fit-tests, scientists measure the number of particles inside the mask versus outside the mask while someone is actually wearing the mask.

Mask Fit Test Procedure

The fit-test machine measures particles from .02 to 1 microns, which includes the size of the coronavirus.

DIY Mask Fit Test Effectiveness Virus

Across 21 volunteers, the homemade cotton masks captured 50% of 0.02-1 micron particles, compared with 80% for the surgical mask. Thus, DIY masks still managed to capture particles while people were actually wearing them. Based on this data, the researchers concluded that homemade masks would be better than nothing.

DIY homemade masks should only be used as a last resort for capturing viruses

Coronavirus & Mask Livestream

Wondering whether masks work to protect you against the coronavirus? Check out our livestream recap covering all the info here!

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, but what about other materials? A group of researchers in the Netherlands tested homemade masks made from dish cloth (called “tea cloth” in the UK).

DIY homemade mask made out of tea cloth

They also used a fit-test machine to test the masks while people were actually wearing them.

Homemade DIY tea cloth mask tests testing how long you can use them for

The dish cloth mask captured 60% of the .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.

DIY Mask Cloth Effectiveness Particle Capture

How Long Can You Wear DIY Masks for?

Next, they tested the DIY masks’ effectiveness after people had worn them for 3 hours. Do masks become less effective after getting all wet and humid?

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.

Homemade DIY Mask Effectiveness Children

Interestingly, the surgical masks and FFP2 (N95) 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.

Children's Mask Fit Test

Bottom Line: DIY Masks for Fighting Viruses

Although they capture fewer particles than surgical and N95 masks, 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. 

Covid19 coronavirus best masks materials fundraiser

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Acv Acv

The article i was looking for! In Turkey, you have to wear masks everywhere. They are slightly cheap so almost everyone using surgical masks but they are causing pollution so i was making a research what if we wear homemade masks. Sooo i’ll stick to surgical masks for a while.

Barbara Ffrench

? I heard that nonwoven interfacing has fibres that are very close together, ie 0.3 microns, and thuuse make an excellent layer in a D.I.Y. facemask. True?

Liz - Smart Air

Hi Barbara, Liz here! In general, natural fiber works better than synthetics, tightly waved fiber works better than loose knit. We have how to pick the material here in this article: You can pick the material fits your needs the best!


When talking about a tea or dish towel, is that for the terry cloth fabric towels, or more like a flour sack smooth cotton dish towel? We have both in the United States. Please clarify to someone who doesn’t live abroad, and, isn’t familiar with the type of dish towels there. It’s hard to tell from the pictures if it’s terry cloth or flour sack material. Thank you.

Liz - Smart Air

Hi Laurie, Liz here. The tea towel is the terry cloth fabric towels.


(1) Wouldn’t it be better to have the special filtering layer (e.g., non-woven polypropylene, heavy/dense Pellon interfacing, etc.) as a 2nd layer of the mask–be part of the constructed mask, sandwiched between tightly woven, high-thread cotton or cotton blendINSTEAD of having it as an “insert”. If it is an “insert”, won’t the incoming air take the path of lease resistance and enter the mask in the areas where the filter is not there? (2) Any suggestions for a “fit test” for a cotton face mask? From what I’ve read, if you have a good mask material-wise–at least 3 layers, with… Read more »

Hi Gretchen, great thoughts here! For fit-testing, I’m presuming you don’t have a $10,000 quantitative fit-test machine! Without that, I recommend trying out what I call the “poor man’s fit test.” I describe how to do that here: For the filter layer, I share your intuition! Unfortunately I don’t have any good data on it. My guess is that, if the filter is very strong, then very little air will want to go through the filter. Instead, it’ll go through the weaker parts of the mask. But if it’s a more moderately strong filter, the difference may be smaller.… Read more »

Dr Pravesh Mehra

How about disinfecting the mask, using 1% hypochlorite solution.
Then drying in a clean area either under UV light or sun for 3 hrs.
Then reusing.
So, for every 8 hrs of use, disinfect n dry, use for the next 6 days.
Hope the fit n filtration stays to the prescribed limits.
This will clearly help us, as healthcare providers, n be economical, cost effective and at the same time provide quality care, during this time of pandemic.

Liz - Smart Air

Hi Dr. Pravesh, Liz here. Have you read our article on how to disinfect the mask? Here is the link: we also have an article on how UV light can help to disinfect the mask, So leaving the mask under UV light and let it dry for a enough amount of time would do the work.