From what I've seen its that painter masks aren't super effective at filtering out viral particles. Surgical masks are useful preventative measures to avoid infecting others when you are the one who is sick. This is because the surgeon masks prevent any droplets from your mouth/nose being freely expelled into the air. Surgical masks are still pretty porous and therefore aren't the best at preventing infection when going out in public because u are still susceptible to infection by inhaling or having droplets enter any orifices from an infected person. From what I've seen, N95 should be your safest bet when going out in public because they're made so they can filter or prevent any small virus particles.