: Which DIY mask is most effective? There have been a number of do-it-yourself (DIY) mask designs released and tested by both universities and other institutions on account of world wide Personal Protection Equipment (PPE)

DIY Designs - most do not carry efficacy data claims

Note that many of these are only respiratory protection designs. You also need to protect your eyes in a high risk situation eg. looking after an infected relative. Get protective goggles or your own glasses and attach a plastic shield eg. plastic pamphlet holder to the glasses for a full face shield.

Combined mask with face shield

University of Hong Kong-Shenzen Paper Towel Mask

Claims 90% filter protection of a surgical mask

Masks only

Freesewing sew your own mask from cotton T-shirt etc

A4 PDF Pattern

CDC letter - simple mask (uses heavyweight T shirt material)

CDC

Instructables Cloth Masks patterns

as with all cloth based, wash in hot water to pre-shrink

Instructables

Copper 3D design using PLA 3-D printer

seems to need their special filter but perhaps use HEPA material?

3d printed masks unsafe poor fit or build up of CO2

Instructions

Face shield only

Prusa Printers RC2
Budmen 3D Printed Face Sheild V2
Laser Cut Shield - University of Auckland

Field Respirators

First industrialized field 3D printed emergency respiration device to support hospitals and ICUs.

Door Handle Opener

Hands free Materialise Door handle Opener

More Reading
smartairfilters.com/en/blog/best-materials-make-diy-face-mask-virus/

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From {1}:

References:

{1} 2020-03-25 - Stanford COVID-19 Evidence Service - Addressing COVID-19 Face Mask Shortages [v1.2] archive.org/details/20200325stanfordcovid19evidenceserviceaddressingcovid19facemaskshortagesv1.2

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In a scenario of being forced to choose from DIY designs (yikes!): Perhaps understanding: How are masks tested for efficacy? would provide insight into comparing DIY mask designs.

Efficacy Test example: www.astm.org/Standards/F2101.htm
Possible Mask features that drive efficacy:

physical design: does the design effectively position the filter?
filter material & design: Which materials will work better than others?
comfort: Will users be able to wear these for extended periods without discomfort?

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Here is a relevant link on the best materials to use in creating a handmade face mask:
www.cambridge.org/core/journals/disaster-medicine-and-public-health-preparedness/article/testing-the-efficacy-of-homemade-masks-would-they-protect-in-an-influenza-pandemic/0921A05A69A9419C862FA2F35F819D55
Also, here is relevant study on the effectiveness of a saline solution applied to a face mask that can kill flu-like viruses (through the osmotic effect) even within five minutes:
www.thestar.com/news/canada/2020/02/11/salt-is-the-secret-ingredient-in-these-face-masks-that-could-prevent-spread-of-next-coronavirus.html www.nature.com/articles/srep39956

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There is literature to support that wearing a mask decreases transmission of infection ([Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C. et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med 26, 676–680 (2020).1), however, there is exceedingly limited evidence that wearing an improvised mask is anywhere near as effective as standard protective equipment (N95 respirator or better).

However, with that said, although I wear a powered air purifying respirator at work (and my company owns the equipment specifically for my personal use, so I could in theory use it elsewhere), I use a homemade cotton mask when outside of home for routine tasks (shopping, getting the vehicle fixed, etc.).

As others have said, wearing a mask is for protection of others from droplets that you might generate, and as such these masks function similar to how the surgical mask was designed (to protect the patient from the surgeon, not vice versa). If everyone was to wear a mask, this could be compared to the concept of "herd immunity" where people are protecting each other. It is a bigger concept than purely personal protection, which an improvised mask fails at any way you wish to look at it.

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