Ah, it's that time of year again. The pitter patter of children's feet. The laughter of high school students as they flirt with each other.
The coughs of their parents.
Is a Portable Air Cleaner (PAC) on a desk aimed at the wee ones' faces going to protect them?
TLDR? No. They need to be in a N95 or KF94 purchased from legit distributors, not from Amazon, and eat their food outdoors, spaced far enough away from their friends so as not get infected. Or use @sipmask and protein shakes at lunch in the cafetaria.
You need to teach them
about how it can take as little as one breath of uncleaned-air to get infected (100 virions study on my profile). How it can mess them up in terms of their entire body.
You need to have the "Birds and the Bees and Covid" talk, in other words.