N95 masks filter up to 95% of airborne particles when approved by NIOSH and a proper fit can be achieved. However, people should know that about 60% of KN95 masks in the United States are counterfeit and do not meet NIOSH standards. The CDC says you should wear the most protective mask possible that you wear regularly, that fits you well, and that is comfortable. Respirators such as non-surgical N95s provide the most protection.
KN95 and medical masks provide the next highest level of protection. CDC says N95 surgical masks should be reserved for healthcare providers. In closed public settings, surgical masks reduce the likelihood of testing positive by 66 percent, the CDC estimated. The top-of-the-line N95 and KN95 masks, the tight-fitting face coverings often worn by healthcare workers, reduce the likelihood of infection by 83 percent, the health agency said.
Cloth masks are those without a test standard that include cotton masks, self-made cloth masks and other substitutes. Taking into account limited resources in some regions, homemade masks have been shown to have comparable filtration efficiencies compared to medical masks. Gaps may be due to choosing the wrong size or type of mask and when wearing a mask with facial hair. These properties can also affect how easily you can breathe through the mask and how effectively the surgical mask protects you.
Until now, research communities have not been able to provide conclusive and unified comments on the effectiveness of masks on fundamental mechanisms and specific functions, although all states in the United States have recently issued requirements for face masks. Surgical masks also do not provide complete protection against germs and other contaminants due to the loose fit between the surface of the mask and the face. Prolonged wearing of tight-fitting masks can lead to bruising and facial abrasions, but bandages over these areas, such as wound barriers commonly seen over the nasal bridge, disrupt the mask's sealing. Learn how to improve your mask protection by visiting the CDC Improve How Your Mask Protects You page.
A recent study published in the journal Proceedings of the National Academy of Sciences estimated that the risk of transmission of COVID-19 can be reduced by up to 75 times when a sick person and someone close to them wear N95-style masks instead of surgical masks. They found that the particles traveled about four feet when participants were without a mask, compared to about two feet in a cloth mask and less than one foot in a surgical mask. Choose masks that have flexible nose straps, as they help prevent air from escaping through the top of the mask. If your surgical mask is damaged or dirty, or if you find it difficult to breathe through the mask, you should remove it, safely dispose of it, and replace it with a new one.
As health officials struggle to minimize the spread of the highly contagious Omicron variant, many experts have recommended that people switch from cloth or surgical masks to more protective N95 and KN95 masks. Surgical masks should not be shared and may be labeled as surgical, isolation, dental, or medical procedure masks.