Which face masks actually work against COVID-19?

Facemasks have become big drivers of e-commerce. In August, Etsy’s quarterly earnings report showed mask sales on the site reached $346 million in the second quarter of 2020. During the same period, face mask sales netted the struggling retailer Gap Inc. $130 million. And the global mask market is projected to grow to $2.3 billion by 2027. Cloth and paper masks routinely make best seller lists