Making effective DIY masks
A research-backed guide to help you choose the best materials to make the most effective masks.
A few weeks ago the prevailing school of thought was an N-95 or nothing because everything else seemed useless in preventing COVID-19 infection. Even surgical masks were portrayed as having little or no preventive abilities against the virus by some news outlets. I think some of the initial misinformation disseminated stemmed from the fear that people would panic buy masks and hoard them as they did with toilet paper and disinfectant. But now thanks to the CDC’s recommendations masked faces are slowly becoming a norm in our dystopian present.
To Mask Or Not to Mask
Here are a few reasons to join the mask ‘trend’, If you are still on the fence ….
- COVID-19 spreads through respiratory droplets from breathing sneezing or coughing
- Even the most basic masks, your respiratory droplets will have a shorter projectile hence reduce the likelihood of spreading it.
- Many carriers are asymptomatic, so you could be infected and a mask would slow the rate of spread.
- If you get an N95 or a well-made home mask (made with the right materials) then you can actually decrease the likelihood of becoming infected with COVID-19 from another person’s droplets.
The Spectrum
SARS-CoV — 2 ranges from around 0.2 to several hundred microns.
The N95 Respirator, considered the best mask to have, is able to prevent about 90% of particles as small as 0.3 microns when fitted well. Then there's the medical-grade surgical mask made of polypropylene, which has a filtration rate of 60–80%. And then there's the home mask which is useful for larger sized particles and primarily as a way to prevent others from your droplets. Here’s a great table of masks. Of the many materials tested scarfs and bandanna masks were deemed the least protective.
Research
A research article published in the Cambridge Journal of Disaster Med Public Health Preparedness in 2013 titled: Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic, compared homemade masks to commercially available masks.
It was shown that although homemade masks made with cotton t-shirts reduced the number of microorganisms expelled via respiratory droplets, surgical masks were proven to be 3 times more effective against influenza viral particles.
The conclusion of the study considered homemade mask ‘as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection’. (Disaster Med Public Health Preparedness. 2013;0:1–6)(Cambridge)
Although this is true we have found that the efficacy of a homemade mask is dependent on the materials used. According to the study by Dr. Prof. Supratik Guha at University of Chicago:
Homemade masks made of natural silk or chiffon and high thread cotton may boost protection. Using this combination was proven to prevent 80–99% of aerosolized particles.
The Light Test
Dr. Scott Segal, of Wake Forest Baptist Health, states that a simple way to determine which fabrics are better than others is to do a light test. Which is hold up the material against the light the more you can see the light through the material the worse it is.
Non-cloth materials
Air filters have been tested with allergy-reduction HVAC filter being the best. The problem is, these filters have tiny fibers that can be inhaled. To prevent this, the best method is to place an air filter between a cloth mask. Other household items like coffee filters are great for filtering but have low efficacy because it’s difficult to breathe with.
Quick tips for materials
- Combo 1: chiffon + natural silk or polyester-cotton flannel
- Combo 2: No Sewmask Combo but place HVAC air filter in the middle
- Combo 3: A cotton quilt with cotton-polyester batting
- Make your mask multilayer — 4 layers better than 2
- Natural fibers are generally better than synthetic fibers.
- Mask should be washed regularly — more care tips here
Your mask is only as good as its weakest link — make sure it has a snug fit!
How to Determine your Mask is a good fit and Comfortable
(1) normal breathing,
(2) deep breathing,
(3) head moving side to side,
(4) head moving up and down,
(5) talking aloud (reading a prepared paragraph),
(6) bending at the waist as if touching their toes, and
(7) normal breathing
(Source: Cambridge)
No-Sew Mask
If the idea of attempting to sew anything is causing anxiety, then check out the CDC’s super easy No-Sew mask instructions
TL:DR
- Masks reduce the likelihood of infection, but it will not eliminate the risk
- Wearing a mask does not mean you should stop social distancing
- Wear a mask whether you think you have the symptoms or not.
- Any mask is better than none.
- Continue washing your hands and prevent touching your face.
- If you are interested in creating masks for health care workers #projectprotect will send you the material and resources you need to make the mask and mail it back to them.
