The inventor of N95 masks had retired. But he now works 20 hours a day, mostly for free, to fight covid-19.

Washington Post:

Peter Tsai retired two years ago, but the materials scientist says he’s never been busier.

When the novel coronavirus began gripping the globe in March, Tsai was summoned from his short-lived retirement. He was in urgent demand because he is the inventor who, in 1995, patented the filtration material used in disposable N95 respirators.