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 Cloth Mask Virus Capture Surgical Mask

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 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 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.

Covid19 coronavirus best masks materials fundraiser

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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.


I recommend testing Norwex microfiber masks. They are just being produced and tests show they capture 81% of .1 micron sized particles. I think that warrants further investigation. They are washable and reusable. Making them not only economical and safer than DIY masks, but also more eco-friendly than disposable masks.

Dawnie Dávila

How often do you need to replace filter?

Liz - Smart Air

Hi Dawnie, we haven’t tested any mask with an inserted layer yet. But if you want to use one, I’d say replace it as often as you would replace your mask. However, I don’t see the point of replacing just the middle layer when the outer layer is the most like to get in contact with the virus (if there’s any).


Are you asking about the Norwex microfiber mask? If so, there are no filters. Thd masks are made of the same microfiber material we use in our window cloths. Tbe fibers are extremely small, only 1/200th of a human hair.

Dominique Cuccia

What are the materials of your mask? They are printed- so what makes yours different than home made?

Liz - Smart Air

Hi Dominique, Liz here from Smart Air. Check out this new article for more testing materials we’ve done in the past weeks with more details on the materials we used:


Hi Dominique! Norwex’s microfiber is unlike anything you can buy off a shelf. Norwex’s personal use masks are made from the same microficer as their Window Cloths. All of Norwex’s microfiber is 1/200th the width of a human hair!! With homemade, you do not have access to microfiber that small. Most store bought microfiber is only split 6 ways, while Norwex’s fibers are split at least 200 ways. Hope that helps.

Jose Casiano

Ok what about microfiber towels. I detail cars and notice this on the package of one of my bags of microfiber towels. Useful Tip: Did you know that microfiber picks up approximately 99% of bacteria and viruses without the need of chemicals.
I have the larger packs i figure that a tighter not pattern would be best.

Liz - Smart Air

Hi Jose, We haven’t tested the microfiber towels yet. We know there’s a huge demand for reliable, science-backed data right now, so we’ve created a campaign to gather information on what our readers wants to test. To vote on what test you expect to see and support our campaign, visit our page here: