> But kids are in school, together, for 6+ hours a day.
This is probably the relevant variable. If you're sharing the same air space with someone carrying an airborne virus, it probably doesn't matter that a mask is filtering 95% if you're both breathing the same air in an enclosed space for 6 hours. Some minimal viral load is needed for infection, and even with 95% filtering you'll probably surpass that threshold after 6 hours.
This is probably the relevant variable. If you're sharing the same air space with someone carrying an airborne virus, it probably doesn't matter that a mask is filtering 95% if you're both breathing the same air in an enclosed space for 6 hours. Some minimal viral load is needed for infection, and even with 95% filtering you'll probably surpass that threshold after 6 hours.