N95

N95 is a designation for a type of filtering respirator used in the United States. It refers to a class of particulate respirators approved by the National Institute for Occupational Safety and Health (NIOSH). N95 respirators are designed to filter out at least 95 percent of airborne particles.

NIOSH tests N95 respirators with a 0.3-micron sodium chloride aerosol and requires at least 95 percent filtration efficiency for non-oil particles. The “N” indicates the filter is not resistant to oil. Other NIOSH grades include R95 (some oil resistance) and P95 (oil-proof). Some N95s used in healthcare are labeled as Surgical N95s, which must meet additional fluid-resistance requirements and, in some cases, FDA clearance.

Certification and labeling: NIOSH-approved respirators carry an approval number and the manufacturer name or mark. The designation alone does not guarantee protection in all situations; proper fit and use are essential.

Design and use: N95s are commonly cup-shaped or fold-flat and are worn as a tight seal over the nose and mouth. A user seal check should be performed each time the respirator is donned; facial hair and a poor seal can reduce effectiveness. Most disposable models are intended for single use, though some can be decontaminated for limited reuse under controlled conditions.

Limitations: N95 respirators protect primarily against airborne particles and do not guard against gases or vapors. Their effectiveness depends on a proper fit, and protection may be reduced if the respirator becomes damaged, wet, or poorly maintained. They are widely used in healthcare, construction, and industrial settings and are available in various styles to suit different faces.