OccuSafe Industrial Hygiene Consulting

There has been confusion during the COVID-19 pandemic on which facemask provides the best protection, an N-95 respirator or a surgical mask. An N-95 respirator has been tested by the National Institute of Occupational Safety & Health (NIOSH), a governmental organization, which is under the Centers for Disease Control (CDC). It has been laboratory tested to be 95% efficient for particulates, mists, and aerosols but is not rated for oil mists. An N95 respirator can be in the form of a dust mask, filters on a half or full-face respirator, or on an air positive air-purifying respirator (PAPR). For greater protection, NIOSH also approves some dust masks and filters that are rated to be 97% or 100% efficient.

To be effective, respirators must fit properly. Only then can they reduce the wearer’s exposure to the contaminant for which it is designed to minimize. This includes when the respirator is initially issued and fit tested and when the user wears the respirator out in the field. Failure to ensure proper fit can make the respirator ineffective and give the wearer a false sense of security. In addition, the user should be trained on how to properly wear, fit, change, and maintain it. Facial hair should not interfere with the seal of the respirator.

Surgical masks are fluid-resistant, disposable, and loose-fitting devices that create a physical barrier between the mouth and nose of the wearer but do not provide as much protection as an N95 respirator. Unlike respirators, surgical masks do not seal tightly to the wearer’s face, and therefore do not provide a reliable level of protection from inhaling infectious aerosols.

The U.S. Food and Drug Administration (FDA) reviews and clears for marketing surgical masks under 21 CFR 878.4040 as Class II medical devices. They may be labeled as surgical masks, surgical masks with an antimicrobial/antiviral agent, or pediatric/child facemask. Surgical masks can be used in many configurations and are not required to be tested for filtering efficiency.

Due to the current shortage of N-95 respirators, these devices should be reserved for medical personnel and first responders who have the greatest exposure to the novel corona virus. Recently, the CDC has recommended that the public wear face coverings in public, which may include all sorts of face coverings including homemade or commercial cloth coverings. They are meant to prevent the wearer from spreading a virus to others more than protecting wearer from exposure. In this time of worldwide pandemic, the general public should use a surgical mask or any other device that prevents the respiration of aerosols.

Be well, be smart, be 6 feet apart!