Hello dear readers,
it these days – March 2020, there is something common as danger in the world, no meter of your country. We are sharing one major problem – the Coronavirus or SARS-2 virus, which one is causing the Covid-19 deseese.
No matter the country you are, I’m pretty sure you have a problem buying a normal surgical mask for your protection. This is the reason why so many people start to produce their own surgical masks for their family. Most of them are using unknown fabric with unknown properties. So in this post, I want to share some studies with you, so you can end with a reasonable protection.
Let’s get started with little understandings about the virus and how the mask works:
How big is the Coronavirus SARS-2 / 2019-nCovid / Covid-19 virus
I will not explain everything for this virus, but the most important thing for this topic. The SARS-2 / 2019-nCovid / Covid-19 virus is relatively big virus. His dimensions vary from 50 nm to 100 nm in diameter. Keep in mind that your surgical mask material has to have a permeability for part smaller than this 50nm for 100% filtration from Coronavirus SARS-2 / 2019-nCovid / Covid-19 virus. This is the best possible solution.
The following picture will give you a breafly example what is the normal filtration for such big particle as the Coronavirus SARS-2 / 2019-nCovid / Covid-19 virus for different materials:
The author’s credits are in the picture
Keep in mind, that this is very, very briefly explained. The study is from researchers at Cambridge University. They tested household materials properties for homemade surgical masks. To measure effectiveness, they shot Bacillus atrophaeus bacteria (0.93-1.25 microns) and Bacteriophage MS virus (0.023 microns in size) at different household materials. Still the results are impressive for some materials.
Some of us will ask your self, okay, but what if we use double or triple layers? Some of the materials will be effective, but some will be not. Let’s see here:
The author’s credits are in the picture
As you can see, some of them are better, some not so much. Mainly it depends of the material that you use for your biological mask.
Okay, but how we can test our surgical mask?
Yes, a good question. We don’t have a viruses nor a sensors to measure this, right? I found a quite simple way to test our surgical mask. For some of us, it will be not so comfortable to do it, but… come on we are in pandemic times – we can use tobacco smoke! Yes, the deadly tobacco smoke! 🙂
According to Taiwan Association for Aerosol Research, they made a research that can be found here:
Aerosol and Air Quality Research, 13: 324–332, 2013
From the results we can find, that the tobacco smoke consist a particles from 100nm to 400nm – few times bigger than the Coronavirus SARS-2 / 2019-nCovid / Covid-19 virus, but you can still understand how worst is your DIY surgical mask!
Remember this is not a scientific test – it’s just a test that you can understand how worst is your material for your diy surgical mask.
My understanding for DIY medical mask test is that you can use a tobacco smoke. All you have to do is inhale a smoke from tobacco and exhale it trough the mask.
Make deep inhale, and start to exhale with not so much force. Be sure all of the exhaled smoke is going trough the mask. If there is no smoke at the other side of the mask, your mask is not so worst and definitely will be better than nothing! So, if the input and output smoke is different, your mask is filtering. You have to think how much by looking at the differences of the two – output and input. Keep in mind that if you use vapor from e-cigarettes they have a water vapor which is not easy to filter 🙂
Please, test my theory and report it here! Thank you!
Other tips for DIY surgical (medical) masks:
– Don’t wear them for long time – use them only you are moving around other people.
– Disinfect them with alcohol with concentration more than 70%.
– Use them with glasses.
– Never touch your surgical mask with undisinfected hands.
