Up until now it's been all willy-nilly when it comes to face masks. Besides the N95 mask, what other face coverings are safe enough to keep COVID-19 at bey?
Quartz reports that a safety standard is finally being hammered out (bolding mine):
ASTM International, an organization that develops and sets all kinds of technical standards, is working with a number of industry and government partners to establish guidelines for the filtration efficacy of "barrier face coverings" (what ASTM calls face masks) sold by private industry. In the end, masks will bear some sort of label certifying they've met the guidelines.
Consumers need such a standard because there's a lot of variation in how well face coverings stop particles outside a medical setting. According to one 2008 study, N95 masks reduce exposure to respiratory viruses by 99%; surgical masks by 74%; and homemade tea towel masks by 58%. Another study, published this month, found that single layers of several common fabrics—polyester, cotton, silk, and linen—were especially ineffective because they are made of porous materials. In June, the World Health Organization published recommendations for a multi-fabric, three-layer mask, but few products sold today look anything like that design…
…ASTM's efforts started in July, and Marshall says a standard could be published before the end of 2020.
Having such a standard wouldn't kill the market for homemade masks that has proliferated on sites like Etsy, which sold $346 million worth of the products between March and August. "This standard is targeted…at the commercial manufacturers producing the vast majority of masks being sold today," says Marshall, noting that such a standard is also voluntary…
image of Snow White wearing a very questionable face mask via Children's Fairyland