A letter published in the Centers for Disease Control publication, Emerging Infectious Diseases (Volume 12, Number 6---June 2007) by Virginia M. Dato, David Hostler, and Michael E. Hahn from the University of Pittsburgh, Pittsburgh, Pennsylvania, USA*, compares the effectiveness of N95 masks to cotton masks. The authors created a "Simple Respiratory Mask" using layers of heavy-weight, bleached and pre-shrunk,100% cotton t-shirt fabric, all designed to protect health care workers during a past Avian Flu epidemic.
(See "Figure" below to view the mask, or see: https://wwwnc.cdc.gov/eid/article/12/6/05-1468-f1). The complete article about the testing process for their home made mask (shown below), may be found at: https://wwwnc.cdc.gov/eid/article/12/6/05-1468_article#tnF1
Prototype mask. A) Side view, B) Face side. This mask consisted of 1 outer layer (≈37 cm × 72 cm) rolled and cut as in panel B with 8 inner layers (<18 cm="" span="">) placed inside (against the face). The nose slit was first placed over the bridge of the nose, and the roll was tied below the back of the neck. The area around the nose was adjusted to eliminate any leakage. If the seal was not tight, it was adjusted by adding extra material under the roll between the cheek and nose or by pushing the rolled fabric above or below the cheekbone. Tie b was tied over the head. A cloth extension was added if tie b was too short. Finally, tie c was tied behind the head. The mask was then fit tested. ( https://wwwnc.cdc.gov/eid/article/12/6/05-1468-f1 )18>
*Citation: Dato, V. M., Hostler, D., & Hahn, M. E. (2006). Simple Respiratory Mask. Emerging Infectious Diseases, 12(6), 1033-1034. https://dx.doi.org/10.3201/eid1206.051468.
The Coronavirus (COVID-19) spread has caused a shortage of N95 masks, moving those who sew to step up and provide free mask patterns and instructions online, so more people may may sew these masks at home. Most mask patterns are similar to surgical masks. (Some mask-makers have even re-purposed individual foam bra cups in their masks.)
No claims have been made that home made masks are as effective as N95 masks, however. Authors state that are being used by some health care workers in shortage areas, with some medical institutions requesting that community members help sew masks for health care workers in their region.
The Centers for Disease Control and Prevention have some excellent advice about the use of protective clothing during the Coronavirus (COVID-19) outbreak, plus tips on masks and how they may be used to protect ourselves and others:
The CDC also has a large section of their Web site devoted to information about Coronavirus (COVID-19), at: https://www.cdc.gov/coronavirus/2019-ncov/index.html
If you or your group likes to sew, here are links to more surgical-style masks you can make at home:
From Joost De Cook at the FreeSewing.org Open Source Project in the Netherlands: https://freesewing.org/blog/facemask-frenzy/
The Turban Project (A site to aid cancer patients) also provides surgical mask patterns online: https://courierpressblogs.com/pdf/howtomakeafacemask.pdf
The New York Post has published an article which includes face mask patterns at: https://nypost.com/2020/03/20/doctors-are-now-running-out-of-face-masks-heres-how-to-make-your-own/
SewEasy.com also has face mask patterns online at: https://so-sew-easy.com/face-mask-sewing-patterns/
A home made mask may help, yet they are still not as effective as an N95 mask, according to the CDC, which has this caution online:
In settings where facemasks are not available, HCP might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort. However, homemade masks are not considered PPE, since their capability to protect HCP is unknown. Caution should be exercised when considering this option. Homemade masks should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face. https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/face-masks.html#crisis-capacityMany thanks to T.J. McCue and Forbes Magazine, for Calling all People Who Sew and Make, their March 20, 2020 article on sewing masks to aid health care workers: https://www.forbes.com/sites/tjmccue/2020/03/20/calling-all-people-who-sew-and-make-you-can-help-solve-2020-n95-type-mask-shortage/#2aebe3e34e41