![Surgical N95](https://upload.wikimedia.org/wikipedia/commons/1/12/Surgical_N95.jpeg)
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
Mechanical filters are a class of filter for air-purifying respirators that mechanically stops particulates from reaching the wearer's nose and mouth. They come in multiple physical forms.
Mechanism of operation
Mechanical filter respirator ...
, which provides protection against
particulates
Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The ter ...
but not against
gas
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma).
A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...
es 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
Peter Tsai (Chinese: 蔡秉燚; born February 6, 1952) is a Taiwanese-American inventor and material scientist who is best known for inventing and patenting the N95 mask filter. He is an expert in the field of nonwoven fabric. Tsai was a Professor ...
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
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
are required to meet at least 94% filtration, and
KN95
Mechanical filters are a class of filter for air-purifying respirators that mechanically stops particulates from reaching the wearer's nose and mouth. They come in multiple physical forms.
Mechanism of operation
Mechanical filter respirator ...
respirators of
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
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
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...
and
Health Canada
Health Canada (HC; french: Santé Canada, SC)Health Canada is the applied title under the Federal Identity Program; the legal title is Department of Health (). is the Structure of the Canadian federal government#Departments, with subsidiary unit ...
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
Some familiar household synthetic polymers include: Nylons in textiles and fabrics, Teflon in non-stick pans, Bakelite for electrical switches, polyvinyl chloride (PVC) in pipes, etc. The common PET bottles are made of a synthetic polymer, polye ...
fibers, specifically a
nonwoven polypropylene
Melt blowing is a conventional fabrication method of micro- and nanofibers where a polymer melt is extruded through small nozzles surrounded by high speed blowing gas. The randomly deposited fibers form a nonwoven sheet product applicable for fil ...
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
OSHA or Osha may refer to:
Work
* Occupational Safety and Health Administration, a federal agency of the United States that regulates workplace safety and health
* Occupational Safety and Health Act (United States) of 1970, a federal law in the Un ...
(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
Facial hair is hair grown on the face, usually on the chin, cheeks, and upper lip region. It is typically a secondary sex characteristic of human males. Men typically start developing facial hair in the later stages of puberty or adolescence, ...
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
Claustrophobia is the fear of confined spaces. It can be triggered by many situations or stimuli, including elevators, especially when crowded to capacity, windowless rooms, and hotel rooms with closed doors and sealed windows. Even bedrooms with ...
. 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
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...
, construction
Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and com ...
, and paint
Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...
ing. 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
The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent advers ...
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 lubricant
A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ...
s, cutting fluids, or glycerine
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
. For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended. They are not effective during firefighting
Firefighting is the act of extinguishing or preventing the spread of unwanted fires from threatening human lives and destroying property and the environment. A person who engages in firefighting is known as a firefighter.
Firefighters typically ...
, in oxygen-deficient atmosphere
Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen, rather than atmospheric air (which is composed largely of nitrogen and oxygen). Examples ...
, 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
Hazardous waste is waste that has substantial or potential threats to public health or the environment. Hazardous waste is a type of dangerous goods. They usually have one or more of the following hazardous traits: ignitability, reactivity, co ...
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
In software engineering, version control (also known as revision control, source control, or source code management) is a class of systems responsible for managing changes to computer programs, documents, large web sites, or other collections o ...
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
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
as a medical device similar to a surgical mask
A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of re ...
. 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
The Families First Coronavirus Response Act is an Act of Congress () meant to respond to the economic impacts of the ongoing COVID-19 pandemic. The act provides funding for free coronavirus testing, 14-day paid leave for American workers affected ...
, 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
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
.
In the United States, the Occupational Safety and Health Administration
The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agenc ...
(OSHA) requires healthcare workers who are expected to perform patient activities with those suspected or confirmed to be infected with COVID-19
Coronavirus disease 2019 (COVID-19) is a contagious disease caused by a virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was COVID-19 pandemic in Hubei, identified in Wuhan, China, in December ...
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
''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on its c ...
'', avian influenza, severe acute respiratory syndrome (SARS), pandemic influenza
An influenza pandemic is an epidemic of an influenza virus that spreads across a large region (either multiple continents or worldwide) and infects a large proportion of the population. There have been six major influenza epidemics in the las ...
, and Ebola
Ebola, also known as Ebola virus disease (EVD) and Ebola hemorrhagic fever (EHF), is a viral hemorrhagic fever in humans and other primates, caused by ebolaviruses. Symptoms typically start anywhere between two days and three weeks after becom ...
.
Unlike a respirator, a surgical mask
A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of re ...
is designed to provide barrier protection against droplets and does not have an air-tight seal and thus does not protect its wearer against airborne particles such as virus material to the same extent.[ ]
Use during shortages
During crisis situations where there is a shortage of N95 respirators, such as the COVID-19 pandemic
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
, the U.S. Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
(CDC) has recommended strategies for optimizing their use in healthcare settings.[ ] N95 respirators can be used beyond their manufacturer-designated shelf life, although components such as the straps and nose bridge material may degrade, making it particularly important that the wearer perform the expected seal check. N95 respirators can be reused a limited number of times after being removed, as long as they have not been used during aerosol-generating procedures and are not contaminated with patients' bodily fluids, because this increases the risk of surface contamination with pathogens. The respirator manufacturer may recommend a maximum number of donnings or uses; if no manufacturer guidance is available, preliminary data suggests limiting to five uses per device. Respirators approved under standards used in other countries and are similar to NIOSH-approved N95 respiratorsincluding FFP2 and FFP3 respirators regulated by the European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
can be used.
According to NIOSH, respirators may still be used in crisis situations if standard respirator fit testing is not available, as a respirator will still provide better protection than a surgical mask or no mask. In this case, best practices for getting a good face seal include trying different models or sizes, using a mirror or asking a colleague to check that the respirator is touching the face, and doing multiple user seal checks.
Given that the global supply of personal protective equipment
Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, elec ...
(PPE) is insufficient during the pandemic, as of 2 February 2020, the World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
recommends minimizing the need for PPE through telemedicine; physical barriers such as clear windows; allowing only those involved in direct care to enter a room with a COVID-19 patient; using only the PPE necessary for the specific task; continuing use of the same respirator without removing it while caring for multiple patients with the same diagnosis; monitoring and coordinating the PPE supply chain
In commerce, a supply chain is a network of facilities that procure raw materials, transform them into intermediate goods and then final products to customers through a distribution system. It refers to the network of organizations, people, acti ...
; and discouraging the use of masks for asymptomatic
In medicine, any disease is classified asymptomatic if a patient tests as carrier for a disease or infection but experiences no symptoms. Whenever a medical condition fails to show noticeable symptoms after a diagnosis it might be considered asy ...
individuals. It should be stressed that for advice updates up until 3 July 2020, the CDC and WHO recommend individuals wear non-medical face coverings in public settings where there is an increased risk of transmission and where social distancing measures are difficult to maintain. Many countries and local jurisdictions encourage or mandate the use of face masks or cloth face coverings by members of the public to limit the spread of the virus.
When it is no longer possible for all healthcare workers to wear N95 respirators when caring for a COVID-19 patient, CDC recommends that respirators be prioritized for workers performing aerosol-generating procedures on symptomatic persons, and those within three feet of an unmasked symptomatic person. Under these conditions, masking of symptomatic patients with a surgical mask
A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of re ...
and maintaining distance from the patient are particularly important to reduce the risk of transmission. When no respirators are left, workers who are at higher risk for severe illness may be excluded from caring for patients, and workers who have clinically recovered from COVID-19 may be preferred to care for patients. Portable fans with HEPA
HEPA (, high-efficiency particulate air) filter, also known as high-efficiency particulate absorbing filter and high-efficiency particulate arrestance filter, is an efficiency standard of air filters.
Filters meeting the HEPA standard must sa ...
filters may also be used to increase ventilation in isolation rooms when surgical masks are being used in place of respirators. A high-quality HEPA filter can trap 99.97% of dust particles that are 0.3 microns in diameter. If neither respirators nor surgical masks are available, as a last resort, it may be necessary for healthcare workers to use masks that have never been evaluated or approved by NIOSH or homemade masks, such as cloth face mask
A cloth face mask is a mask made of common textiles, usually cotton, worn over the mouth and nose. When more effective masks are not available, and when physical distancing is impossible, cloth face masks are recommended by public health agenci ...
s, although caution should be exercised when considering this option.
Decontamination
Disposable filtering facepiece respirators such as N95 respirators are not approved for routine decontamination and reuse as standard of care. However, their decontamination and reuse may need to be considered as a crisis capacity strategy to ensure continued availability.[ ]
There have been efforts to evaluate cleaning methods for respirators in emergency shortages, although there is concern that this may reduce filter performance, or affect mask fit by deforming the mask. Duke University
Duke University is a private research university in Durham, North Carolina. Founded by Methodists and Quakers in the present-day city of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco and electric power industrialist James ...
researchers have published a method for cleaning N95 respirators without damaging them using vaporized hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%†...
to allow reuse for a limited number of times. Battelle received an Emergency Use Authorization from the U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...
for its technology used to sterilize N95 respirators.
OSHA does not currently have any standards for disinfecting N95 respirators. NIOSH recommends that during shortages N95 respirators may be used up to five times without cleaning them, as long as aerosol
An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be natural or Human impact on the environment, anthropogenic. Examples of natural aerosols are fog o ...
-generating procedures are not performed, and respirators are not contaminated with patients' bodily fluids
Body fluids, bodily fluids, or biofluids, sometimes body liquids, are liquids within the human body. In lean healthy adult men, the total body water is about 60% (60–67%) of the total body weight; it is usually slightly lower in women (52-55%) ...
. Contamination can be reduced by wearing a cleanable face shield
A face shield, an item of personal protective equipment (PPE), aims to protect the wearer's entire face (or part of it) from hazards such as flying objects and road debris, chemical splashes (in laboratories or in industry), or potentially ...
over an N95 respirator, as well as using clean gloves when donning and seal-checking a used N95 respirator and discarding the gloves immediately after. According to CDC, ultraviolet germicidal irradiation
Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses short-wavelength ultraviolet (ultraviolet C or UV-C) light to kill or inactivate microorganisms by destroying nucleic acids and disrupting their DNA, leaving them unabl ...
, vaporous hydrogen peroxide and moist heat showed the most promise as potential methods to decontaminate N95 respirators and other filtering facepiece respirators.
Contrast with surgical mask
A surgical mask
A surgical mask, also known by other names such as a medical face mask or procedure mask, is a personal protective equipment used by healthcare professionals that serves as a mechanical barrier that interferes with direct airflow in and out of re ...
is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. If worn properly, a surgical mask is meant to help block large-particle droplets
A drop or droplet is a small column of liquid, bounded completely or almost completely by free surfaces. A drop may form when liquid accumulates at the lower end of a tube or other surface boundary, producing a hanging drop called a pendant d ...
, splashes, sprays, or splatter that may contain viruses and bacteria. Surgical masks may also help reduce exposure of the wearer's saliva and respiratory secretions to others.[ ]
A surgical mask, by design, does not filter or block very small particles in the air that may be transmitted by coughs, sneezes, or certain medical procedures. Surgical masks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the face mask and the face. Collection efficiency of surgical mask filters can range from less than 10% to nearly 90% for different manufacturers’ masks when measured using the test parameters for NIOSH certification. However, a study found that even for surgical masks with "good" filters, 80–100% of subjects failed an OSHA-accepted qualitative fit test, and a quantitative test showed 12–25% leakage.[ ]
The U.S. Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...
recommends surgical masks (over no mask) in procedures where there can be an aerosol
An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be natural or Human impact on the environment, anthropogenic. Examples of natural aerosols are fog o ...
generation from the wearer, if small aerosols can produce a disease to the patient.
History
N95 respirators have several historical predecessors. In the late 19th century, Miles Philips began using a "mundebinde" ("mouth bandage") of sterilized cloth which he refined by adapting a chloroform mask with two layers of cotton mull. Paul Berger
Paul Berger (; 6 January 1845 Beaucourt, Territoire de Belfort – 1908) was a French physician and surgeon who practised in Paris at the Hôpital Tenon and was Professor of Clinical Surgery and Pathology at the Faculté de médecine de Paris. ...
, a Paris surgeon, likewise investigated the protective effect of masks during surgery. Another mask design was a cloth facemask by Lien-teh Wu
Wu Lien-teh (; Goh Lean Tuck and Ng Leen Tuck in Minnan and Cantonese transliteration respectively; 10 March 1879 – 21 January 1960) was a Malayan physician renowned for his work in public health, particularly the Manchurian plague of 1910 ...
, who was working for the Chinese Imperial Court in the autumn of 1910 during the Manchurian plague
The Manchurian plague was a pneumonic plague that occurred mainly in Manchuria in 1910–1911. It killed 60,000 people, stimulating a multinational medical response and the wearing of the first personal protective equipment (PPE).
__TOC__
Histor ...
outbreak. It inspired masks used during the 1918 flu pandemic
The 1918–1920 influenza pandemic, commonly known by the misnomer Spanish flu or as the Great Influenza epidemic, was an exceptionally deadly global influenza pandemic caused by the H1N1 influenza A virus. The earliest documented case was ...
. Another predecessor was gas mask
A gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Most gas mask ...
s developed during World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, which were adapted for use by miners. They were reusable but bulky and uncomfortable due to their fiberglass
Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...
filters and heavy rubber construction.
Mass production of filtering facepieces was started in 1956 in the Soviet Union (the first mass-produced model was called meaning "petal" in Russian). The air was purified with nonwoven filtering material consisting of polymeric fibres carrying a strong electrostatic charge
Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respectiv ...
. Respirator was used in nuclear industry (as single-used PPE), and then in other branches of economy. In about 60 years, more than 6 billion respirators were manufactured. Unfortunately, the developers overestimated the efficiency ( APF 200–1000), which led to serious errors in the choice of personal protective equipment
Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, elec ...
by employers.
In the 1970s, the US Bureau of Mines and NIOSH developed standards for single-use respirators, and the first single-use N95 "dust" respirator was developed by 3M and approved in 1972. 3M used a melt blowing process that it had developed decades prior and used in products such as ready-made ribbon
A ribbon or riband is a thin band of material, typically cloth but also plastic or sometimes metal, used primarily as decorative binding and tying. Cloth ribbons are made of natural materials such as silk, cotton, and jute and of synthetic mater ...
bows and bra
A bra, short for brassiere or brassière (, or ; ), is a form-fitting undergarment that is primarily used to support and cover breasts. It can serve a range of other practical and aesthetic purposes, including enhancing or reducing the appear ...
cups; its use in a wide array of products had been pioneered by designer Sara Little Turnbull
Sara Little Turnbull (née Finkelstein; September 21, 1917 – September 3, 2015) was an American product designer, design innovator and educator. She advised corporate America on product design from 1935 – 2005, and has been described as "corp ...
.
Originally designed for industrial use, N95 respirators became a healthcare
Health care or healthcare is the improvement of health via the prevention, diagnosis, treatment, amelioration or cure of disease, illness, injury, and other physical and mental impairments in people. Health care is delivered by health profe ...
standard subsequent to virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
-blocking technology invented by University of Tennessee
The University of Tennessee (officially The University of Tennessee, Knoxville; or UT Knoxville; UTK; or UT) is a public land-grant research university in Knoxville, Tennessee. Founded in 1794, two years before Tennessee became the 16th state, ...
professor Peter Tsai
Peter Tsai (Chinese: 蔡秉燚; born February 6, 1952) is a Taiwanese-American inventor and material scientist who is best known for inventing and patenting the N95 mask filter. He is an expert in the field of nonwoven fabric. Tsai was a Professor ...
, and patented in 1995. The novel material consists of both positive and negative charges, which are able to attract particles (such as dust, bacteria and viruses) and trap at least 95% of them by polarization before the particles can pass through the mask. The anti-viral technology was first developed to prevent the spread of drug-resistant tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
. Following the onset of the COVID-19 pandemic
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
, Tsai ended his retirement to help alleviate shortages related to the COVID-19 pandemic
In economics, a shortage or excess demand is a situation in which the demand for a product or service exceeds its supply in a market. It is the opposite of an excess supply ( surplus).
Definitions
In a perfect market (one that matches a sim ...
by researching N95 mask decontamination.[
Many American companies stopped producing N95 respirators in the 2000s due to litigation costs and foreign competition.
]
Global shortages during the COVID-19 pandemic
On January 24, 2020, Taiwan announced that it was imposing a temporary ban on the export of masks. The respirators came to be in short supply and high demand during the COVID-19 pandemic
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
, causing price gouging and hoarding, often leading to confiscation of masks. Production of N95 respirators was limited due to constraints on the supply of nonwoven polypropylene
Melt blowing is a conventional fabrication method of micro- and nanofibers where a polymer melt is extruded through small nozzles surrounded by high speed blowing gas. The randomly deposited fibers form a nonwoven sheet product applicable for fil ...
fabric (which is used as the primary filter) as well as the cessation of exports from China.
In Canada, AMD Medicom began making masks in 1997 through an agreement with United Medical Enterprises in Atlanta, Georgia, US. Medicom added factories in Shanghai in 2002, Yilan Taiwan in 2010 and France in 2011. As the pandemic escalated, China, France and Taiwan either prohibited the export of masks, or requisitioned Medicom's output for local use. The federal government of Canada came to an agreement with Medicom to buy millions of masks over the next ten years, leading to Medicom announcing plans to open a new factory; in Montreal. Novo Textiles in British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
quickly acquired a surgical mask making machine, and announced plans to acquire an N95 making machine as well.
In March 2020, US President Donald Trump
Donald John Trump (born June 14, 1946) is an American politician, media personality, and businessman who served as the 45th president of the United States from 2017 to 2021.
Trump graduated from the Wharton School of the University of Pe ...
applied the Defense Production Act (DPA) against the American company 3M that allows the Federal Emergency Management Agency
The Federal Emergency Management Agency (FEMA) is an agency of the United States Department of Homeland Security (DHS), initially created under President Jimmy Carter by Presidential Reorganization Plan No. 3 of 1978 and implemented by two Exec ...
to obtain as many N95 respirators as it needs from 3M.
Also in early April 2020, the United States federal government
The federal government of the United States (U.S. federal government or U.S. government) is the Federation#Federal governments, national government of the United States, a federal republic located primarily in North America, composed of 50 ...
, invoking the DPA, ordered 3M to stop exporting N95 respirators to customers in Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
and Latin America
Latin America or
* french: Amérique Latine, link=no
* ht, Amerik Latin, link=no
* pt, América Latina, link=no, name=a, sometimes referred to as LatAm is a large cultural region in the Americas where Romance languages — languages derived f ...
, and to keep them within the U.S. instead. However, 3M refused, citing humanitarian implications, and the possibility of backfire: "Ceasing all export of respirators produced in the United States would likely cause other countries to retaliate and do the same, as some have already done. If that were to occur, the net number of respirators being made available to the United States would actually decrease. That is the opposite of what we and the administration, on behalf of the American people, both seek."
Selected patents
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See also
*List of Taiwanese inventions and discoveries
This is a list of inventions by people who were born in Taiwan (officially known as Republic of China) or citizens of Republic of China.
Food, food techniques and cuisine
;Bubble tea
:is a drink that contains flavored tea and tapioca pearls. ...
*Mechanical filter (respirator)
Mechanical filters are a class of filter for air-purifying respirators that mechanically stops particulates from reaching the wearer's nose and mouth. They come in multiple physical forms.
Mechanism of operation
Mechanical filter respirator ...
References
External links
{{Commons category, N95 (mask), N95 respirator
Q & A—Masks and COVID-19
by the WHO
"A Certain Type of N95 Respirator May Do More Harm Than Good"
at Healthline (front valve N95 respirators only protect the wearer)
1972 introductions
Medical masks
Respirators