Introduction to N95 Protective Masks

An N95 respirator is a particle filtering mask that meets the National Institute for Occupational Safety and Health (NIOSH) N95 air filtration classification and can filter at least 95% of airborne particles. It provides protection against particulates, but no protection against gases or vapors.

N95 respirators are considered functionally equivalent to certain respirators prescribed in countries other than the United States. Such as the EU's FFP2 respirator and China's KN95 respirator. N95 masks require a fine web of synthetic polymer fibers, created through a process called melt blowing, that creates an inner filter layer that filters out harmful particles.

Industrial applications

N95 masks were originally designed for industrial use in industries such as mining, construction, and paint. Effective protection against engineered nanoparticles has been demonstrated.

N series respirators, including N95 masks, are only effective when there are no oil particles such as lubricating oil, cutting fluid or glycerin. For substances that are harmful to the eyes, a protective face shield is recommended. They are not effective in firefighting, hypoxia, or unknown environments; in such cases, self-contained breathing apparatus is recommended.

medical use

N95 masks are approved both as respirators by NIOSH and as medical devices similar to surgical masks by the U.S. Food and Drug Administration (fda). As part of the Families First Coronavirus Response Act, in response to a shortage of respirators during the COVID-19 pandemic, the liability and certification laws were changed to allow the use of N95 masks in healthcare settings.

In the United States, the Occupational Safety and Health Administration (OSHA) requires healthcare workers to wear N95 masks when engaging in activities with patients suspected or confirmed to have COVID-19.

Unlike N95 masks, surgical masks are only designed to provide barrier protection against droplets and do not have an airtight seal to protect the wearer to the same degree from airborne particles such as viral substances.

Use during shortages

N95 masks, not approved as standard care for daily cleaning and reuse. However, their decontamination and reuse may need to be considered as a crisis response strategy to ensure continued availability.

Researchers at Duke University have unveiled a method for cleaning N95 masks that can be reused a limited number of times using evaporated hydrogen peroxide without damaging the respirator.

NIOSH recommends that in the event of a shortage, N95 respirators can be used up to five times without cleaning, as long as the aerosol-generating process is not going on and the respirators are not contaminated with the patient's body fluids. Contamination can be reduced by wearing a cleanable face shield over N95 respirators, as well as using clean gloves when using N95 respirators, and discarding gloves immediately after checking the seal.

Compared to surgical masks

A surgical mask is a loose, single-use device that creates a physical barrier between the wearer's mouth and nose and potentially contaminates the surrounding environment. Surgical masks, because of the looseness between the mask surface and the face, can help block large droplets, splashes, splatters or splashes that may contain viruses and bacteria, and cannot completely prevent bacteria and other contaminants. When using NIOSH-certified test parameters to measure masks from different manufacturers, surgical mask filtration rates ranged from 10% to 90%. Even surgical masks with "good" filters failed osha-approved qualitative fit tests in 80-100% of subjects, while quantitative tests showed 12-25% leakage,

history

The N95 mask has several historical predecessors. One is a cloth face mask designed by Lien-teh Wu. In the autumn of 1910, when the plague broke out in Manchuria, Wu Liande worked in the Chinese court. It was the first mask to protect users from bacterial infection in experimental tests and was used during the 1918 flu pandemic. Another predecessor was a gas mask developed during World War I and used by miners. They are reusable but bulky and uncomfortable due to their fiberglass filters and heavy rubber construction, single-use respirators were standardised in the 1970s by the Bureau of Mines and NIOSH , 3M developed the first N95 mask, which was approved in 1972.