A gas mask is a piece of personal protective equipment 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 masks are also respirators, though the word gas mask is often used to refer to military equipment, the scope used in this article. Gas masks only protect the user from ingesting or inhaling chemical agents, as well as preventing contact with the user's eyes. Most combined gas mask filters will last around 8 hours in a biological or chemical situation. Filters against specific chemical agents can last up to 20 hours.
HEPA filter, also known as a high efficiency particulate arresting filter, is an efficiency standard of air filters.
A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres including lead fumes, vapors, gases and particulate matter such as dusts and airborne pathogens such as viruses. There are two main categories of respirators: the air-purifying respirator, in which respirable air is obtained by filtering a contaminated atmosphere, and the air-supplied respirator, in which an alternate supply of breathable air is delivered. Within each category, different techniques are employed to reduce or eliminate noxious airborne contaminants.
A particulate air filter is a device composed of fibrous, or porous materials which removes particulates such as smoke, dust, pollen, mold, viruses and bacteria from the air. Filters containing an adsorbent or catalyst such as charcoal (carbon) may also remove odors and gaseous pollutants such as volatile organic compounds or ozone. Air filters are used in applications where air quality is important, notably in building ventilation systems and in engines.
A dust mask is a flexible paper pad held over the nose and mouth made for protection against chronically toxic nuisance dusts, like from occupational exposure to plant dusts like hay. They are not intended to provide protection from most airborne hazards. The European FFP1 mask, the lowest-grade standard available in the jurisdiction, is an example of a dust mask, being only certified to remove ~80% of dusts and mists.
ANSI/ISEA 110-2003, the American National Standard for Air-Purifying Respiratory Protective Smoke Escape Devices was established to define test criteria and approval methods for fire/smoke escape hoods published by the American National Standards Institute (ANSI). ANSI/ISEA 110 provides design guidance to Respiratory Protective Smoke Escape Devices (RPED) manufacturers in the form of a detailed set of performance requirements and testing procedures. Key sections of the standard cover certification, labeling, design, performance, conditioning and testing requirements.
The clean air delivery rate (CADR) is a figure of merit that is the cubic feet per minute (CFM) of air that has had all the particles of a given size distribution removed. For air filters that have air flowing through them, it is the fraction of particles that have been removed from the air, multiplied by the air flow rate through the device. More precisely, it is the CFM of air in a 1,008-cubic-foot (28.5 m3) room that has had all the particles of a given size distribution removed from the air, over and above the rate at which the particles are naturally falling out of the air. Different filters have different abilities to remove different particle distributions, so three CADR's for a given device are typically measured: smoke, pollen, and dust. By combining the amount of airflow and particle removal efficiency, consumers are less likely to be misled by a high efficiency filter that is filtering a small amount of air, or by a high volume of air that is not being filtered very well.
A respirator fit test checks whether a respirator properly fits the face of someone who wears it. The fitting characteristic of a respirator is the ability of the mask to separate a worker's respiratory system from ambient air.
A respirator cartridge or gas mask canister is a type of filter that removes gases, volatile organic compounds (VOCs), and other vapors from the air through adsorption, absorption, or chemisorption. It is one of two basic types of filters used by air-purifying respirators. The other is a mechanical filter, which removes only particulates. Hybrid filters combine the two.
A powered air-purifying respirator (PAPR) is a type of respirator used to safeguard workers against contaminated air. PAPRs consist of a headgear-and-fan assembly that takes ambient air contaminated with one or more type of pollutant or pathogen, actively removes (filters) a sufficient proportion of these hazards, and then delivers the clean air to the user's face or mouth and nose. They have a higher assigned protection factor than filtering facepiece respirators such as N95 masks. PAPRs are sometimes called positive-pressure masks, blower units, or just blowers.
The respiratory protective devices (RPD) can protect workers only if their protective properties are adequate to the conditions in the workplace. Therefore, specialists have developed criteria for the selection of proper, adequate respirators, including the Assigned Protection Factors (APF) - the decrease of the concentration of harmful substances in the inhaled air, which to be provided with timely and proper use of a certified respirator of certain types (design) by taught and trained workers, when the employer performs an effective respiratory protective device programme.
Respiratory protective equipment (RPE), also called protective breathing equipment (PBE) in the US, is a form of personal protective equipment designed to protect the wearer from a variety of airborne hazards in the form of a gas, fume, mist, dust or vapour. Respirators filter the air to remove harmful particles and alongside the breathing apparatus (BA) provides clean air for the worker to breathe.
Respirators, also known as respiratory protective equipment (RPE) or respiratory protective devices (RPD), are used in some workplaces to protect workers from air contaminants. Initially, respirator effectiveness was tested in laboratories, but in the late 1960s it was found that these tests gave misleading results regarding the level of protection provided. In the 1970s, workplace-based respirator testing became routine in industrialized countries, leading to a dramatic reduction in the claimed efficacy of many respirator types and new guidelines on how to select the appropriate respirator for a given environment.
The health and safety hazards of nanomaterials include the potential toxicity of various types of nanomaterials, as well as fire and dust explosion hazards. Because nanotechnology is a recent development, the health and safety effects of exposures to nanomaterials, and what levels of exposure may be acceptable, are subjects of ongoing research. Of the possible hazards, inhalation exposure appears to present the most concern, with animal studies showing pulmonary effects such as inflammation, fibrosis, and carcinogenicity for some nanomaterials. Skin contact and ingestion exposure, and dust explosion hazards, are also a concern.
An N95 respirator is a disposable filtering facepiece respirator or reusable elastomeric respirator filter that meets the U.S. National Institute for Occupational Safety and Health (NIOSH) N95 standard of air filtration, filtering at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers under 42 CFR 84, effective July 10, 1995. A surgical N95 is also rated against fluids, and is regulated by the US Food and Drug Administration under 21 CFR 878.4040, in addition to NIOSH 42 CFR 84. 42 CFR 84, the federal standard which the N95 is part of, was created to address shortcomings in the prior United States Bureau of Mines respirator testing standards, as well as tuberculosis outbreaks, caused by the HIV/AIDS epidemic in the United States. Since then, N95 respirator has continued to be used as a source control measure in various pandemics that have been experienced in the United States and Canada, including the 2009 swine flu and the COVID-19 pandemic.
Mechanical filters, a part of particulate respirators, 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.
Peter Tsai is a Taiwanese-American inventor and material scientist who is best known for inventing and patenting improved meltblown filtration manufacturing techniques, used in respirators (like N95 respirators, which is a 1995 NIOSH standard made to address the shortcomings of USBM standards). He is an expert in the field of nonwoven fabric. Tsai was a Professor Emeritus at the University of Tennessee, but ended his retirement during the COVID-19 pandemic to research mask and respirator sterilization.
Source control is a strategy for reducing disease transmission by blocking respiratory secretions produced through breathing, speaking, coughing, sneezing or singing. Multiple source control techniques can be used in hospitals, but for the general public wearing personal protective equipment during epidemics or pandemics, respirators provide the greatest source control, followed by surgical masks, with cloth face masks recommended for use by the public only when there are shortages of both respirators and surgical masks.
Elastomeric respirators, also called reusable air-purifying respirators, seal to the face with elastomeric material, which may be a natural or synthetic rubber. They are generally reusable. Full-face versions of elastomeric respirators seal better and protect the eyes.
The European respirator standards refer to the filtering classification by EN 149, EN 14683, and EN 143, all European standards of testing and marking requirements for respirators. FFP standard masks cover the nose, mouth and chin and may have inhalation and/or exhalation valves.
