surgical mask is good only for one shift work, it goes together with other personal protective devices. Can not change them while inside a bio-security area. For general public use , it is not so critical but change as often as piratical. Can not reuse uncleaned and unsanitized masks due to cross-contamination.thought a surgical face mask would be good for just for like half of an hour (or less), and then (or sooner) should be replaced, but what do I know
Further info on sanitizing alcohol I mention before. Pure alcohol (100%) is not as effective because after initial scotching the bacterial, it create a sort of protective surface cover for the bacterial by blocking further penetration of the alcohol.