copper-infused face mask idea has been around for a while. Proposed in 2010 article listed by NIH. 
copper-infused face masks were also used in Korea, one of most successful countries in dealing with COVID. See this interesting presentation:
copper has unique anti-viral properties and, in addition, can be infused in fabrics in interesting ways.
I've been meaning to tweet about copper and its anti-viral properties for some time. Coronavirus dies on copper surfaces more than 10 times faster than on stainless steel or plastic surfaces. Its anti-viral (and anti-bacterial) properties have long been known.
Copper producers have long tried to interest hospitals in copper surfaces and copper-infused fabrics even prior to COVID. Seems like it would make a lot of sense right now, especially given dangerous working conditions for medical people.
in Canada, one nurse has tried to get licensed by Health Canada to market medical clothing (gowns) made with copper-infused fabrics, but, after a year of bureaucratic stonewalling, seems to have given up.
I've done quite a bit of recent research into copper and had been meaning to write about it. Some of my knowledge areas are a little quirky: I worked for a large copper producer when I was in my 20s and know a great deal about copper markets.
in Taiwan, some organizations placed adhesive-backed copper tape (used in electronics usually, I think) onto frequently touched surfaces to kill virus. See focustaiwan.tw/society/202003…
I spent some time recently looking for sources for these high-tech copper-infused fabrics and also nanoporous copper. All of these high-tech materials seem to be available only or almost only in China. They seem to have moved well beyond merely copying.
