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Respirator
A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres including lead, 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. Air-purifying respirators range from relatively inexpensive, single-use, disposable face masks, known as filtering facepiece respirators, reusable models with replaceable cartridges called elastomeric respirators, to powered air-purifying respirators (PAPR), which use a pump or fan to constantly move air through a filter and supply purified air into a mask, helmet or hood. History Earliest records to 19th c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N95 Respirator
An N95 respirator is a disposable Respirator#Filtering facepiece, 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 median aerodynamic diameter#Mass median aerodynamic diameter, 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 in the United States, HIV/AIDS epidemic in the United States. Since then, N95 respirator has continued to be used as a Source control (respiratory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastomeric Respirator
Elastomeric respirators, also called reusable air-purifying respirators, seal to the face with elastomeric material, which may be a Natural rubber, natural or synthetic rubber. They are generally reusable. Full-face versions of elastomeric respirators seal better and protect the eyes. Elastomeric respirators consist of a reusable mask that seals to the face, with exchangeable filters. Elastomeric respirators can be used with chemical cartridge filters that remove gases, Mechanical filter (respirator), mechanical filters that retain particulate matter, or both. As particulate filters, they are comparable (or, due to the quality and error-tolerance of the elastomeric seal, possibly superior) to filtering facepiece respirators such as most ''disposable'' N95 respirators and FFP masks. Elastomeric air-purifying respirators are designed to be safely reused for years. Provided the cartridge integrity and filter have not been compromised, current practice shows that the filters could b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filtering Facepiece Respirator
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. Mechanism of operation Mechanical filter respirators retain particulate matter such as dust created during woodworking or metal processing, when contaminated air is passed through the filter material. Wool is still used today as a filter, along with plastic, glass, cellulose, and combinations of two or more of these materials. Since the filters cannot be cleaned and reused and have a limited lifespan, cost and disposability are key factors. Single-use, disposable and replaceable-cartridge models exist. Mechanical filters remove contaminants from air in the following ways: # by ''interception'' when particles following a line of flow in the airstream come within one radius of a fiber and adhere to it; # by ''impaction'', when larger particles unable to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Powered Air-purifying Respirator
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 Respirator assigned protection factors, assigned protection factor than filtering facepiece respirators such as N95 masks. PAPRs are sometimes called positive-pressure masks, blower units, or just blowers. Description The modularity of PAPRs allows them to be customized for different working environments. Regardless of type, a PAPR consists of: * some kind of headgear (mask or hood), * a powered (motor-driven) fan (mechanical), fan which forces incoming air into the device, * a filter (air), filter (or multiple filters) for delivery to the user for breathing, and * a battery or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NIOSH
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury, illness, disability, and death. Its functions include gathering information, conducting scientific research both in the laboratory and in the field, and translating the knowledge gained into products and services.About NIOSH National Institute for Occupational Safety and Health. Among NIOSH's programs are determination of recommended exposure limits for toxic chemicals and other hazards, field research such as the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particulate Matter
Particulate matter (PM) or particulates are microscopic particles of solid or liquid matter suspended in the air. An ''aerosol'' is a mixture of particulates and air, as opposed to the particulate matter alone, though it is sometimes defined as a subset of aerosol terminology. Sources of particulate matter can be natural or anthropogenic. Particulates have impacts on climate and precipitation that adversely affect human health. Types of atmospheric particles include suspended particulate matter; thoracic and respirable particles; inhalable coarse particles, designated PM, which are coarse particles with a diameter of 10 micrometers (μm) or less; fine particles, designated PM, with a diameter of 2.5 μm or less; ultrafine particles, with a diameter of 100 nm or less; and soot. Airborne particulate matter is a Group 1 carcinogen. Particulates are the most harmful form of air pollution as they can penetrate deep into the lungs and brain from blood streams, ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viruses
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. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or ''virions'', consisting of (i) genetic material, i.e., long molecules of DNA or RNA that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julius Jeffreys
Julius Jeffreys (1800–1877) was a British surgeon and writer, was the inventor of the respirator, and was a pioneer in the development of early air conditioning systems. Early life Julius Jeffreys was born on 14 September 1800 at Hall Place, Bexley, Kent, England, where his father was the principal of a private school. He was the tenth of sixteen children born to the Reverend Richard and Sarah Jeffreys. When he was three, the family moved to India, where his father had accepted a post as chaplain to the British East India Company. While in India the family was based in Calcutta, but spent some months travelling along the Ganges river on a houseboat. Sarah died in 1809. The family returned to England around 1811. Education and training Along with most of his brothers, Julius was educated by their father. Most of his brothers attended Cambridge University, but Julius was admitted to the University of Edinburgh in 1817 to study medicine. He completed his medical education in Lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Stenhouse
John Stenhouse FRS FRSE FIC FCS (21 October 1809 – 31 December 1880) was a British chemist. In 1854, he invented one of the first practical respirators. He was a co-founder of the Chemical Society in 1841. Life John Stenhouse was born in Barrhead in Glasgow on 21 October 1809. He was the eldest son of William Stenhouse, a calico-printer in the family firm of John Stenhouse & Co of 302 High Street, Glasgow, and Elizabeth Currie; he was the only one of their children to survive beyond infancy. After education at the Glasgow Grammar School, he studied at the University of Glasgow from 1824 to 1828. Initially he intended to pursue a career in literature, but later his interests switched to chemistry, which he studied first under Professor Thomas Graham at the university and then under Dr. Thomas Thomson at Anderson's University in Glasgow (now part of the University of Strathclyde, one of whose buildings is named after him). During 1837–1839, he attended the chemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activated Carbon
Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that greatly increase the surface area available for ''adsorption '' or chemical reactions. (Adsorption, not to be confused with Absorption (chemistry), absorption, is a process where atoms or molecules adhere to a surface). The pores can be thought of as a microscopic "sponge" structure. Activation is analogous to making popcorn from dried corn kernels: popcorn is light, fluffy, and its kernels have a high surface-area-to-volume ratio. ''Activated'' is sometimes replaced by ''active''. Because it is so porous on a microscopic scale, one gram of activated carbon has a surface area of over , as determined by gas absorption and its porosity can run 10ML/day in terms of treated water per gram. Researchers at Cornell University synthesized an ultrahigh surface area activated ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Tyndall
John Tyndall (; 2 August 1820 – 4 December 1893) was an Irish physicist. His scientific fame arose in the 1850s from his study of diamagnetism. Later he made discoveries in the realms of infrared radiation and the physical properties of air, proving the connection between atmospheric Carbon dioxide, CO and what is now known as the greenhouse effect in 1859. Tyndall also published more than a dozen science books which brought state-of-the-art 19th century experimental physics to a wide audience. From 1853 to 1887 he was professor of physics at the Royal Institution of Great Britain in London. He was elected as a member to the American Philosophical Society in 1868. Early years and education Tyndall was born in Leighlinbridge, County Carlow, Ireland. His father was a local police constable, descended from Gloucestershire emigrants who settled in southeast Ireland around 1670. Tyndall attended the local schools (Ballinabranna Primary School) in County Carlow until his late t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliny The Elder
Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vespasian. He wrote the encyclopedic (''Natural History''), a comprehensive thirty-seven-volume work covering a vast array of topics on human knowledge and the natural world, which became an editorial model for encyclopedias. He spent most of his spare time studying, writing, and investigating natural and geographic phenomena in the field. Among Pliny's greatest works was the twenty-volume ''Bella Germaniae'' ("The History of the German Wars"), which is Lost literary work, no longer extant. ''Bella Germaniae'', which began where Aufidius Bassus' ''Libri Belli Germanici'' ("The War with the Germans") left off, was used as a source by other prominent Roman historians, including Plutarch, Tacitus, and Suetonius. Tacitus may have used ''Bella Ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
