When shopping for N95 masks, you may want to look up the NIOSH-approved N95 respirator checklist from the CCD, which will verify the masks you are looking at have been tested and conformed to the NIOSH regulations. If you have questions about a particular mask, you can check if it is listed as NIOSH-approved under the N95. You still want to be sure the industrial N95 mask is on this NIOSH-approved list, and will fit properly, tightly over your face.
The next best alternative is a K95 single-use surgical mask, which offers a close fit and good protection, although it is not rated by the CDC as highly as the NIOSH-approved respirators. Loosely knit cloth masks are least effective, but may offer an extra layer of protection if worn over the surgical mask. The CDC suggests a surgical mask over a cloth mask may provide an added layer of protection if using N95 is not feasible.
A cloth mask is better than no mask, but is not as good as a surgical three-layer mask, a KN95, or a N95 respirator for any of the options. N95 and KN95 masks are generally slightly tighter fit than a surgical mask, and the materials also filter more particles, so the air passing through the materials rather than around the mask is filtered better. Among the more protective masks are N95 high-filtration masks, which the CDC notes are also effective enough that health care workers wear them (but remember, they are not surgical masks).
As public health officials race to minimize spread of the highly infectious Omicron strain, many experts are recommending people transition away from cloth or surgical masks toward the more protective N95 and KN95 masks. The CDC recently updated its guidance, stating that cloth masks are not as effective at protecting against the Omicron variation of Covid-19 as other masks. The CDC recently modified the guidance on face masks to include N95 and KN95 respirators, which provide better protection from infection with Covid-19 than cloth or procedure masks.
N95 masks, also known as respirators, have been shown to offer better filtration and protection than cloth masks made before the pandemic. In its guidance to consumers on face masks, CDC notes that N95s and other respirators approved by the National Institutes of Health are the most protective options. Choices include NIOSH-approved N95 masks, which the CDC says provide the highest level of protection; the China-certified KN95; or the Korea-certified KF94.
N95 masks have to go through the NIOSH stringent inspection and certification process, whereas companies making KN95 masks have to get FDA approval via an Emergency Authorization, for foreign certification indicating the mask meets 95 percent of filtration requirements.