The CDC just updated their mask recommendations and said that cloth masks are not as effective as well-fitting surgical masks or respirators (KN95s/non-surgical N95s) in protecting the general population against covid.
Masking is a relatively low risk mitigation technique in otherwise healthy children and our goal is to keep children in school so if masking in general will help reduce the transmission of airborne particles between school children then the benefit outweighs the risk. N95 masks do have the best filtration of all the mask options, but they are arguably the most restrictive and uncomfortable of the options.
The bottom line is that the best mask is one that is well fitting on a child’s face and one that he or she will wear and tolerate wearing properly for the full school day.
We would rather children not have to wear a mask at all during school anymore. However, while not ideal, having to temporarily wear an N95 for multiple hours per day during school would not harm an otherwise healthy low-risk child.