This standard rates masks based on filtration, breathability, and an optional leakage ratio. The CDC has a list of masks here, and it tells which masks pass enough of these criteria to qualify for either of the Workplace Performance labels (as of writing, there are only three that earned the label), but this is all based on data reported by suppliers and manufacturers. If you can't find N95 masks but don't work in a high-risk setting, these are also decent masks to pick up.Also, note that ASTM refers to the agency that classifies standards, but this workplace standard is not the only ASTM standard that governs masks. This standard is technically ASTM F3502-21, which only has the two Workplace Performance levels mentioned above. You may also see other masks that use labels like “ASTM Level 3,” which refer to different ASTM standards for medical masks. For our purposes, all of this means that if you're looking for low-risk masks for the office, look for the Workplace Performance labels.N...
