This helps reduce airborne transmission of pathogens and other aerosolized contaminants between the wearer and nearby people via respiratory droplets ejected when sneezing, coughing, forceful expiration or unintentionally spitting when talking, etc.

[2][3][4] Surgical masks are distinct from filtering respirators, such as those made to the American N95 standard, which are more airtight and purposefully designed to protect against finer airborne particles.

For example, the European EN 14683 Type II standard requires the material of the mask to filter particles (mean diameter close to 3 micrometres) containing the bacterium Staphylococcus aureus.

[13][14][15] In some East Asian countries, masks have often customarily been worn by people who are sick in order to avoid spreading it, to protect against air pollution or allergens, as a fashion statement, or to deter social interaction.

[20][21] A surgical mask serves as a mechanical barrier that interferes with direct airflow in and out of respiratory orifices (i.e. nose and mouth).

A surgical mask is a disposable device that creates a physical barrier between the respiratory tract openings (nose and mouth) of the wearer and potentially pathogenic contaminants in the immediate environment.

[22] Surgical masks help reduce exposure of the wearer's saliva and respiratory secretions to others[24] that could otherwise travel up to 7.9 metres (26 ft).

The outward-facing side of the mask is typically colored (usually blue, green, or yellow) and made thicker, tougher, and water impermeable.

[28] Some masks have an attached thin polyethylene faceshield (known as a "splash shield") to provide additional spray protection over the eye area.

These masks are typically made to the N95/P2 standards, and are commonly used for clinical situations that demand fine particulates protection, such as tuberculosis.

Small strips of foam or thickened fabric are often sewn along the top edge of the mask to help better seal away exhaled water vapors (which can fog up eyewears and faceshields) and soak up excess perspiration dripping from above.

Horizontal loops go around the head like tied straps, designed to exert tension on the top and bottom edges of the mask for firmer contact seal, and are usually seen on duckbill masks; while vertical loops hook around the ears with less tension (due to the weaker rigidity of the elastocartilaginous auricles compared to the bony skull) and thus less firmly secured to the face, but are more popular in non-procedural usages due to the ease of putting on and taking off.

[30][31][32][33][better source needed][medical citation needed] While there is some development work on making electret filtering materials that can stand being washed and reused,[34] current commercially produced electret filters are ruined by many forms of disinfection, including washing with soap and water or alcohol, which destroys the electric charge.

[35] During the COVID-19 pandemic, public health authorities issued guidelines on how to save, disinfect and reuse electret-filter masks without damaging the filtration efficiency.

[39] Face masks for use in surgery were developed in Europe by several physicians, including Jan Mikulicz-Radecki at the University of Breslau and Paul Berger in Paris, in the late nineteenth century, as a result of increasing awareness of germ theory and the importance of antiseptic procedures in medicine.

[40] In response to a pneumonic plague in Manchuria and Mongolia in 1910, Chinese-Malaysian epidemiologist Dr. Wu Lien-teh greatly improved on the designs he had seen in Europe to develop a face mask of layers of gauze and cotton that would protect both the wearer and others.

In community and healthcare settings, the use of face masks is intended as source control to limit transmission of the virus and for personal protection to prevent infection.

[45][47][48] Various case-control and population-based studies have also shown that increased levels of masking in a community reduces the spread of SARS-CoV-2,[47][48] though there is a paucity of evidence from randomized controlled trials (RCTs).

[58][59][60] In community and home settings, the use of facemasks and respirators generally are not recommended, with other measures preferred such as avoiding close contact, maintaining good hand hygiene,[27] and wearing cloth face coverings.

[62] In Japan and Taiwan, surgical masks have commonly been worn in winter months during the flu season by those who have respiratory illnesses as a courtesy intended to prevent viral transmission.

It has been suggested that mask-wearing as a custom appeared in East Asia rather than other parts of the world also facing pollution and disease due to the historical influence of Traditional Chinese Medicine and its ideas about air and wind.

In the European Economic Area (EEA), surgical masks have to be certified through the CE marking process in order to be commercialized.