Surgical masks, which were once just a strip of cloth that attaches to a doctor or nurse's face, are today manufactured using non-woven fabrics made of plastics such as polypropylene to filter and protect. They are also available in many different styles and grades depending on the level of protection the wearer needs.

Surgical masks are designed to keep operating rooms sterile and to prevent the transmission of germs from the user's mouth and nose to the patient during surgery. Although they have seen a rise in popularity among consumers during epidemics such as the coronavirus, surgical masks are not designed to filter out viruses that are smaller than germs.

Masks provide the same protection for the wearer as a non-ventilated mask, but the valve does not prevent viruses from escaping, which could allow someone unaware they are infected to infect others. It's also important to note that a face shield without a mask can spread the virus evenly.

Mask Types

There are four levels of ASTM certification where surgical masks are classified based on the level of protection they provide to the wearer:

    Minimum protection face masks are for brief procedures or examinations with no liquids, sprays or aerosols.
    Level 1 face masks usually have ear loops and are the general standard for both surgical and procedural applications with a fluid resistance of 80 mmHg. For low-risk situations where there will be no liquid, spray, or aerosol.
    Level 2 masks with a liquid resistance of 120 mmHg provide a barrier to light or moderate aerosols, liquids and sprays.
    Level 3 face masks are for possible heavy exposure to aerosol, liquid and spray with a liquid resistance of 160 mmHG.

It should be noted that surgical masks are not the same as surgical respiratory masks. Masks are made to prevent splashes or aerosols (such as moisture from sneezing) and fit loosely to the face. Respirators are made to filter airborne particles such as viruses and bacteria, creating a seal around the mouth and nose. Respirators should be used when patients have a viral infection or particles, vapors or gases.

Surgical masks are also not the same thing as procedural masks. Procedural masks are used in clean environments in hospitals, including intensive care and maternity units, but are not approved for sterile environments such as operating rooms.