N95s

N95s are a class of filtering facepiece respirators certified by the United States National Institute for Occupational Safety and Health (NIOSH). They are designed to seal tightly to the face and filter at least 95% of airborne particles that do not contain oil, as demonstrated under standardized testing. The N designation means not resistant to oil, and the 95 indicates the minimum filtration efficiency. Models that are approved for workplace use carry a NIOSH approval number and labeling that can be checked for legitimacy.

Design and use: Most N95s are disposable and intended for single use, though guidelines may allow limited reuse in shortages. Protection is highly dependent on a proper fit and a good seal; a user seal check should be performed each time the respirator is donned, and fit testing is required in many workplaces for tight-fitting respirators. Some models include an exhalation valve to reduce heat buildup, but valves do not provide source control and may be avoided in sterile or infection-control settings.

Healthcare and variants: Some N95s are also classified as surgical N95s, which meet additional fluid-resistance requirements (per ASTM F1862) and are suitable for procedures with potential exposure to blood or bodily fluids. Not all N95s are surgical; the two categories share the same filtration performance but differ in fluid resistance and regulatory clearance.

Limitations and care: N95s do not protect against gases or vapors. Their effectiveness depends on a proper seal; facial hair and certain facial shapes can impede fit. They are generally not washable and are intended to be discarded when damaged, soiled, difficult to breathe through, or after a prescribed period of use. During supply disruptions, institutions may implement reuse or extended-use policies under guidance from health and safety authorities.