More thoughts on Masks for Infection Prevention for the General Public

I am no longer quite sure how I feel about mask use for the general public. I present some links below for your information. I definitely can not medically vouch for anything in my links or my advice. There is quite a lot of information pro and con about mask use.  I think the following four pieces of advice could be generic enough to be universally recognized as important:

• If possible, don't let your mask use lessen your 'social distancing' practices in general.
• Wear and use your mask with appropriate 'infection control'. Tech yourself 'infection control' for PPE (e.g. masks and gloves)
• Choose a mask(s) based on the best technical and engineering specifications you can afford.
• Do not wear a mask if it negatively effects your breathing so as to put your respiratory or cardiovascular health at risk. (e.g. Don't suffer an asthma or heart attack because of your mask.)

A mask is a safety tool for infection prevention in a Pandemic. Masks are engineered and manufactured to different safety 'ASTM' safety levels. These specifications are worth understanding, even if it is tough to find ASTM certified masks for the general public. The ASTM levels teach you mask effectiveness and some basic mask science.

Obviously, if you are going to work in crowded places or live in crowded cities in a Pandemic, face mask use could really benefit you. You should have a tight fitting face mask that allows you to breathe well. You should change the mask if it becomes moist or infected. Ideally, you may want a high quality washable mask or many disposable masks you can change as needed. Of course, you should 'don' and 'doff' the mask correctly without ever touching the mask face itself. Health and hospital workers routinely use anti-septic gel before and after such 'donning' and 'doffing' of surgical masks. Remember that your mask could be a source of infection to you or others.  Common recognized infectious mask practices include:

• wearing masks around your neck
• wearing the mask under your nose
• wearing a loose fitting mask
• using a contaminated mask from one environment elsewhere
• using a mask with gaps or 'exhale ducts' that leak your breath
• using unclean hands to touch your mask (anywhere)

These practices above are all generally considered infectious practice in clinical and health settings. As a test engineer (but not a medical researcher), I think the best masks for the general public should probably have these characteristics:

• uniform infection preventing material suitable to the target prevention size (e.g. virus microns)
• tight fitting around face and nose but comfortable and breathable so as to be worn continually for the needed period of time
• able to be used with infection control practices that alleviate the threat of mask contamination of yourself or others 
• affordable enough to be used for the above reasons for the appropriate periods of time your mask is needed

Some basic PDFs on ASTM face mask levels
https://healthcentricadvisors.org/wp-content/uploads/2017/04/3_MaskEnomics_Poster_2012.pdf
https://www.cardinalhealth.com/content/dam/corp/web/documents/whitepaper/Face%20Mask%20Selection%20Guide.pdf

Some sites on Infection Control
https://www.cdc.gov/infectioncontrol/index.html
https://www.who.int/infection-prevention/en/
https://www.infectioncontroltoday.com/
https://www.cnbc.com/2020/04/09/how-to-use-and-clean-homemade-face-mask-to-prevent-covid19.html

Interesting Technical Background on Masks from "SmartFilters"
https://smartairfilters.com/en/blog/comparison-mask-standards-rating-effectiveness/
https://smartairfilters.com/en/blog/whats-the-difference-between-n95-and-kn95-masks/
https://smartairfilters.com/en/blog/difference-between-n95-and-kf94-masks/

The WHO vs CDC conflicting advice on Mask Use for the General Public
WHO on Mask use for General Public:
https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks
CDC on Mask use for General Public:
https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html
ABC interview with expert on Why WHO and CDC disagree:
https://abcnews.go.com/Health/cdc-offer-conflicting-advice-masks-expert-tells-us/story?id=70958380
King5 commentary on CDC vs WHO on Mask use for General Public:
https://www.king5.com/article/news/health/coronavirus/to-mask-or-not-to-mask-preventing-spread-in-the-time-of-coronavirus/281-13cfc52a-e9fc-4469-849d-a0b2a942c392

How to wear mask and gloves
https://elemental.medium.com/the-right-way-to-wear-a-mask-and-gloves-399469c0ecf
https://jamanetwork.com/journals/jama/fullarticle/2764955

Hong Kong is making the innovative 'CU Mask +" for all of its residents:
https://www.qmask.gov.hk/
https://www.qmask.gov.hk/about

Expensive but probably well engineered masks
https://hydrafacial.com/facelifemask/
https://o2canada.com/

KN95 masks
https://accumed.com/kn95-mask-for-sale-respirator-safety-mask-k1.html

Some Copper masks:
https://www.coppercompression.com/products/copper-infused-face-mask/
https://www.coppermask.com/
https://copperwearmask.com/
https://cupron.com/cupron-reusable-face-masks/
Copper face masks on Etsy

Articles on Copper as Antimicrobial
https://en.wikipedia.org/wiki/Antimicrobial_properties_of_copper
https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/jam.13681
https://theconversation.com/copper-is-great-at-killing-superbugs-so-why-dont-hospitals-use-it-73103
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3067274/
https://www.smithsonianmag.com/science-nature/copper-virus-kill-180974655/

Well quoted technical piece on the utility of cloth masks as a face covering/antiviral strategy 
https://pubs.acs.org/doi/full/10.1021/acsnano.0c03252
https://pubs.acs.org/doi/10.1021/acsnano.0c03252?goto=supporting-info
https://pubs.acs.org/doi/suppl/10.1021/acsnano.0c03252/suppl_file/nn0c03252_si_001.pdf

Pro Mask: Why we should all Wear Masks
https://www.today.com/health/copper-face-masks-protect-against-coronavirus-do-they-work-t182589
https://medium.com/@Cancerwarrior/covid-19-why-we-should-all-wear-masks-there-is-new-scientific-rationale-280e08ceee71

Against Mask: How face masks for the general public can be Dangerous and Infectious
https://www.news-medical.net/news/20200315/Wearing-masks-may-increase-your-risk-of-coronavirus-infection-expert-says.aspx
https://www.cnn.com/2020/03/02/health/surgeon-general-coronavirus-masks-risk-trnd/index.html
https://www.sciencedaily.com/releases/2015/04/150422121724.htm