N95 and better filter 95% of 0.3 micron particles. But they do BETTER for both larger AND smaller particles. 0.3 microns is the hardest size to filter, even harder than smaller sizes.
Mandates don't work because:
1) they result in mostly theatre, not common sense use of the masks in a beneficial way
2) enforcement increases spread between the people most likely to exhale the virus and officers
3) trying to force people often triggers a disobedience reaction
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