Introduction: Particle Mask to Respirator Mask Modification N95+

​Designers find that layering two blue shop towels inside face masks makes the most effective homemade PPEs

At the beginning of Covid in 2019, California's Suay Sew Shop co-owners Lindsay Medoff and Heather Pavlu fashion designers tested a variety of materials for viral filtration capabilities.

They then bought a $1,400 Grainger particulate-counter device capable of measuring filtration down to 0.3 microns.

They found that 2-layers of easy-to-obtain blue shop towels (the kind usually sold at hardware and automotive stores) had the highest-filtration rates for 0.3 micron-sized particles (Sars-Cov-2 is 0.1 micrometer (µm) (Source).

N95 masks - which hospitals use - effectively block about 95 per cent of particles that are 0.3 microns or larger.

The blue shop towels (cost less than $5 for a 2-pak) are made of a polyester hydro knit and are used for cleaning up spills. They also identified that polypropylene towel that has strong filtration capabilities. They are recommending that people making homemade face masks should try lining them with polyester hydro knit shop towels as a way to increase the filtration rate of cotton masks. Cotton masks alone, filtered only 20 - 60 per cent of those size particles.

Step 1:

Step #1


Take one of the cotton filter pads provided with the mask and trace a pattern on a piece of cardboard. Use this as your template to make your blue shop towel filters.


Step #2


Place (2) blue filters inside the filter box.


Step #3


Close filter box and use as normal on face. Change filters out daily. Disinfect mask buy spraying surface lightly with 70% alcohol.


Cost Break Down


​3M N95 Aura Particulate Respirator 9205+, 10 Pack (source: wal-mart 3/2023) $21.00

Only 10 days protection.


​Equate Earloop Disposable Face Masks, 25 Pack (source: wal-mart 3/2023) $6.00

Does not stop transmission of infectious disease’s. Stated on the box.. Totally worthless.


Reusable Half Mask (source: wal-mart/amazon 3/2023) $10-$12

Blue Shop Towels 2-pak (source: wal-mart 3/2023) $6

Endless supply for N95+ mask!!


Where to Buy Half Mask Face Respirator Protect for Painting Spray Face-piece


Walmart Model #1 (fit unknown)


Amazon Model #1 (blue mouth piece fits large face)


Amazon Model #2 (gray mouth piece fits medium face)