It is pity that the surgical face mask was not studied, because this is the most often used mask. It is often used, because it is cheap and easily accessible in stores, at least, at my place.

Very topical, but hard to take any physics publication seriously when it mixes imperial measurements with metric units. We are trying to bring the rest of the population forward, at least to the 19th century, but this sort of thing keeps dragging us back.