N95 respirator

An N95 filtering facepiece respirator, commonly abbreviated N95 respirator, is a particulate-filtering facepiece respirator that meets the U.S. National Institute for Occupational Safety and Health (NIOSH) N95 classification of air filtration, meaning that it filters at least 95% of airborne particles. This standard does not require that the respirator be resistant to oil; another standard, P95, adds that requirement. The N95 type is the most common particulate-filtering facepiece respirator. It is an example of a mechanical filter respirator, which provides protection against particulates but not against gases or vapors. An authentic N95 respirator is marked with the text "NIOSH" or the NIOSH logo, the filter class ("N95"), a "TC" approval number of the form XXX-XXXX, the approval number must be listed on the NIOSH Certified Equipment List (CEL) or the NIOSH Trusted-Source page, and it must have headbands instead of ear loops.

The N95 mask filter was invented by Taiwanese-American Peter Tsai and his team, and received its U.S. patent in 1995. N95 respirators are considered similar to other respirators regulated under non-U.S. jurisdictions, but slightly different criteria are used to certify their performance, such as the filter efficiency, test agent and flow rate, and permissible pressure drop. For example, FFP2 respirators of the European Union are required to meet at least 94% filtration, and KN95 respirators of China are expected to meet at least 95% filtration. However, NIOSH found that some products labeled "KN95" failed to meet these standards, some of them filtering out as little as one percent. Both the U.S. Food and Drug Administration and Health Canada require such KN95 products failing to meet the filtration standards to be re-labeled as "face masks" instead of "respirators", when being sold in the U.S. and Canada.

The N95 respirator requires a fine mesh of synthetic polymer fibers, specifically a nonwoven polypropylene fabric. It is produced by melt blowing and forms the inner filtration layer that filters out hazardous particles.

Use

Fit testing is a critical component to a respiratory protection program whenever workers use tight-fitting respirators. OSHA (US) requires an initial respirator fit test to identify the right model, style, and size respirator for each worker; as well, as annual fit tests. Additionally, tight-fitting respirators, including the N95, require a user seal check each time one is put on. Facial hair at the sealing area of the respirator will cause it to leak.

Respirators require a medical evaluation before use because they can make breathing more difficult. Some conditions that could prevent respirator use include heart conditions, lung disease, and psychological conditions such as claustrophobia. In the United States medical evaluation is required once, prior to initial fit testing and use, although it may need to be repeated if any adverse signs or symptoms are observed. Correct use of the respirator decreases the chances of airborne contamination by viruses.

For persons who are medically disqualified from negative-pressure respirators, or who cannot pass a fit test due to facial hair or other reasons, a powered air-purifying respirator is a possible alternative.

In industry

N95 respirators were originally designed for industrial use in sectors such as mining, construction, and painting. They have also been shown to be effective as protection against engineered nanoparticles.

According to the NIOSH Respirator Selection Logic, respirators with filters in the N, R, and P series are recommended for concentrations of hazardous particulates that are greater than the relevant occupational exposure limit but less than the immediately dangerous to life or health level and the manufacturer's maximum use concentration, subject to the respirator having a sufficient assigned protection factor.

N series respirators, including the N95 respirator, are only effective in the absence of oil particles, such as lubricants, cutting fluids, or glycerine. For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended. They are not effective during firefighting, in oxygen-deficient atmosphere, or in an unknown atmosphere; in these situations a self-contained breathing apparatus is recommended instead. They are not effective against hazardous gases or vapors, for which a cartridge respirator is recommended.

In industrial settings where infectious disease exposure is not a concern, users can wear and reuse a filtering facepiece respirator until it is damaged, soiled, or causing noticeably increased breathing resistance, unless there is a manufacturer-specified duration of use. However, in laboratories at biosafety level 2 and higher, respirators are recommended to be discarded as hazardous waste after a single use.

Some industrial N95 series respirators have an exhaust valve to improve comfort, making exhalation easier, reducing leakage on exhalation and steaming-up of glasses. It was previously believed that if the exhalation air from those respirators was not filtered, then an additional well-fitting cloth facemask or other exhalation filter needed to be used with the respirator for source control to prevent the spread of disease, such as COVID-19, when worn by asymptomatic, but possibly infected users. Newer research indicates that source control of valved respirators can be "similar to or better than those provided by surgical masks and unregulated barrier face coverings." According to the CDC, the "study also shows that modifications uch as the use of an electrocardiogram pad or surgical tape secured over the valve from the inside of the FFR ..can further reduce particle emissions." The CDC recommends that "In general, individuals wearing NIOSH-approved N95s with an exhalation valve should not be asked to use one without an exhalation valve or to cover it with a face covering or mask."

In healthcare

Respirators used in healthcare are traditionally a specific variant called a surgical respirator, which is both approved by NIOSH as a respirator and cleared by the Food and Drug Administration as a medical device similar to a surgical mask. These may also be labeled "Surgical N95", "medical respirators", or "healthcare respirators". The difference lies in the extra fluid-resistant layer outside, typically colored blue. As part of the Families First Coronavirus Response Act, changes were made to liability and certification laws to allow industrial respirators to be used in healthcare settings, in response to shortages of respirators during the COVID-19 pandemic.

In the United States, the Occupational Safety and Health Administration (OSHA) requires healthcare workers who are expected to perform patient activities with those suspected or confirmed to be infected with COVID-19 to wear respiratory protection, such as an N95 respirator. The CDC recommends the use of respirators with at least N95 certification to protect the wearer from inhalation of infectious particles including ''Mycobacterium tuberculosis'', avian influenza

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