What is an N95?
An N95 respirator is a respiratory protective device designed to achieve a very close facial fit and very efficient filtration of airborne particles.
Most N95 respirators are manufactured for use in construction and other industrial type jobs that expose workers to dust and small particles. They are regulated by the National Personal Protective Technology Laboratory (NPPTL) in the National Institute for Occupational Safety and Health (NIOSH), which is part of the Centers for Disease Control and Prevention (CDC).
Some N95 respirators are intended for use in a health care setting. Specifically, single-use, disposable respiratory protective devices used and worn by health care personnel during procedures to protect both the patient and health care personnel from the transfer of microorganisms, body fluids, and particulate material. All N95s provide the same level of filtration (> 95% of particulates over 0.3 microns), with medical or surgical N95s adding a layer for splash protection.
For the Center for Disease Control's information on NIOSH certification and standards, see https://www.cdc.gov/niosh/index.htm.
What is the difference between an N95 and a regular face mask?
Unlike NIOSH-approved N95s, facemasks are loose-fitting and provide only barrier protection against droplets, including large respiratory particles. Most facemasks do not effectively filter small particles from the air and do not prevent leakage around the edge of the mask when the user inhales. They can provide some protection for the wearer, and provide significant benefits to others in preventing the wearer from potentially spreading COVID-19.
A note from the CDC about N95 respirators (and when standard or surgical is required)
"N95 respirators include standard and surgical N95 respirators. In the United States, all N95 respirators used in occupational settings are approved by the National Institute for Occupational Safety and Health (NIOSH) and used in accordance with OSHA standards.
A surgical N95 respirator is a NIOSH-approved N95 respirator that has also been cleared by the FDA as a surgical mask. Surgical N95 respirators (sometimes called medical respirators) are recommended only for use by HCP who need protection from both airborne and fluid hazards, such as splashes or sprays. In times of shortage, only HCP who are working in a sterile field or who may be exposed to high-velocity splashes, sprays, or splatters of blood or body fluids should be provided these respirators. Other HCP can use standard N95 respirators. If surgical N95 respirators are not available, and there is a risk that the worker may be exposed to high velocity splashes, sprays, or splatters of blood or body fluids, then a faceshield should be worn over the standard N95 respirator."