Note Prof. Lin doesn't yet recommend wanton wearing of masks.:
"– At current infection rates and in normal activities, most people would be wasting masks.
– But masks would be useful in proximity with strangers (airplane, train, Uber/Lyft, and especially hospital or clinic)."

— Mickey Kaus (@kausmickey) March 28, 2020

from Twitter https://twitter.com/kausmickey