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Air purifier
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An air purifier or air cleaner is a device which removes contaminants from the air in a room. These devices are marketed as being beneficial to allergy sufferers and asthmatics. Air purifiers may also be used in industry to remove impurities such as CO2 from air before processing, pressure swing adsorbers or other adsorption techniques are typically used for this. In 1830, a patent was awarded to Charles Anthony Deane, a long leather hose attached to the rear of the helmet was to be used to supply air, the original concept being that it would be pumped using a double bellows. A short pipe allowed breathed air to escape, the garment was to be constructed from leather or airtight cloth, secured by straps. In the 1860s, John Stenhouse filed two patents applying the absorbent properties of charcoal to air purification, thereby creating the first practical respirator. A few years later, John Tyndall invented an improvement to the firemans respirator, dust, pollen, pet dander, mold spores, and dust mite feces can act as allergens, triggering allergies in sensitive people. Smoke particles and volatile compounds can pose a risk to health. Exposure to various such as VOCs increases the likelihood of experiencing symptoms of sick building syndrome. Air purifiers are becoming capable of capturing a greater number of bacterial, virus. Several different processes of varying effectiveness can be used to purify air, thermodynamic sterilization - This technology uses heat sterilization via a ceramic core with micro capillaries, which are heated to 200 °C. It is claimed that 99. 9% of microbiological particles - bacteria, viruses, dust mite allergens, mold, the air passes through the ceramic core by the natural process of air convection, and is then cooled using heat transfer plates and released. TSS is not a technology, as it does not trap or remove particles. TSS is claimed not to emit harmful by-products and also reduces the concentration of ozone in the atmosphere, ultraviolet germicidal irradiation - UVGI can be used to sterilize air that passes UV lamps via forced air. Air purification UVGI systems can be freestanding units with shielded UV lamps that use a fan to force air past the UV light, other systems are installed in forced air systems so that the circulation for the premises moves micro-organisms past the lamps. Key to this form of sterilization is placement of the UV lamps, for example, forced air systems by design impede line-of-sight, thus creating areas of the environment that will be shaded from the UV light. However, a UV lamp placed at the coils and drainpan of cooling system will keep micro-organisms from forming in these naturally damp places. The most effective method for treating the air rather than the coils is in-line duct systems, filter - based purification traps airborne particles by size exclusion
2.
Fiber
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Fiber or fibre is a natural or synthetic substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials, the strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene. Natural fibers develop or occur in the shape, and include those produced by plants, animals. Plant fibers are employed in the manufacture of paper and textile, wood fiber, distinguished from vegetable fiber, is from tree sources. Forms include groundwood, lacebark, thermomechanical pulp, and bleached or unbleached kraft or sulfite pulps, animal fibers consist largely of particular proteins. Instances are silkworm silk, spider silk, sinew, catgut, wool, sea silk and hair such as wool, mohair and angora, fur such as sheepskin, rabbit, mink, fox, beaver. Mineral fibers include the asbestos group, asbestos is the only naturally occurring long mineral fiber. Six minerals have been classified as asbestos including chrysotile of the serpentine class, short, fiber-like minerals include wollastonite and palygorskite. Instances are collagen family of proteins, tendon, muscle proteins like actin, cell proteins like microtubules and many others, spider silk, sinew, man-made or chemical fibers are fibers whose chemical composition, structure, and properties are significantly modified during the manufacturing process. Man-made fibers consist of regenerated fibers and synthetic fibers, the earliest semi-synthetic fiber is the cellulose regenerated fiber, rayon. Most semi-synthetic fibers are cellulose regenerated fibers, cellulose fibers are a subset of man-made fibers, regenerated from natural cellulose. The cellulose comes from sources, rayon from tree wood fiber, Modal from beech trees, bamboo fiber from bamboo, seacell from seaweed. In the production of fibers, the cellulose is reduced to a fairly pure form as a viscous mass. Therefore, the process leaves few characteristics distinctive of the natural source material in the finished products. Some examples are, rayon bamboo fiber Lyocell, a brand of rayon Modal, historically, cellulose diacetate and -triacetate were classified under the term rayon, but are now considered distinct materials. Synthetic come entirely from materials such as petrochemicals, unlike those man-made fibers derived from such natural substances as cellulose or protein. Metallic fibers can be drawn from ductile metals such as copper, gold or silver and extruded or deposited from more brittle ones, such as nickel, carbon fibers are often based on oxydized and via pyrolysis carbonized polymers like PAN, but the end product is almost pure carbon. Silicon carbide fibers, where the polymers are not hydrocarbons but polymers
3.
Porous
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Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0 and 100%. Strictly speaking, some measure the accessible void, the total amount of void space accessible from the surface. There are many ways to test porosity in a substance or part, the term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, earth sciences, soil mechanics and engineering. Void fraction usually varies from location to location in the flow channel and it fluctuates with time and its value is usually time averaged. In separated flow, it is related to flow rates of the gas and the liquid phase. It is defined by the ratio, ϕ = V V V T where VV is the volume of void-space and VT is the total or bulk volume of material, both the mathematical symbols ϕ and n are used to denote porosity. Porosity is a fraction between 0 and 1, typically ranging from less than 0.01 for solid granite to more than 0.5 for peat and it may also be represented in percent terms by multiplying the fraction by 100. The porosity of a rock, or sedimentary layer, is an important consideration when attempting to evaluate the potential volume of water or hydrocarbons it may contain. Sedimentary porosity is a function of many factors, including but not limited to, rate of burial, depth of burial, the nature of the connate fluids. The principal complication is that there is not a direct proportionality between porosity and hydraulic conductivity but rather an inferred proportionality, there is a clear proportionality between pore throat radii and hydraulic conductivity. Also, there tends to be a proportionality between pore throat radii and pore volume, if the proportionality between pore throat radii and porosity exists then a proportionality between porosity and hydraulic conductivity may exist. Well sorted materials have higher porosity than similarly sized poorly sorted materials, for tables of common porosity values for earth materials, see the further reading section in the Hydrogeology article. Consolidated rocks potentially have more complex dual porosities, as compared with alluvial sediment and this can be split into connected and unconnected porosity. Connected porosity is more easily measured through the volume of gas or liquid that can flow into the rock, porosity is the ratio of pore volume to its total volume. Porosity is controlled by, rock type, pore distribution, cementation, diagenetic history, porosity is not controlled by grain size, as the volume of between-grain space is related only to the method of grain packing. Rocks normally decrease in porosity with age and depth of burial, tertiary age Gulf Coast sandstones are in general more porous than Cambrian age sandstones. There are exceptions to this rule, usually because of the depth of burial and thermal history, porosity of surface soil typically decreases as particle size increases. This is due to soil formation in finer textured surface soils when subject to soil biological processes
4.
Particulates
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Atmospheric particulate matter – also known as particulate matter or particulates – are microscopic solid or liquid matter suspended in the Earths atmosphere. The term aerosol commonly refers to the mixture, as opposed to the particulate matter alone. Sources of particulate matter can be man-made or natural and they have impacts on climate and precipitation that adversely affect human health. The smaller PM2.5 were particularly deadly, with a 36% increase in lung cancer per 10 μg/m3 as it can penetrate deeper into the lungs, some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes, coal combustion in developing countries is the primary method for heating homes and supplying energy. The composition of aerosols and particles depends on their source, wind-blown mineral dust tends to be made of mineral oxides and other material blown from the Earths crust, this particulate is light-absorbing. In addition, sea spray aerosols may contain organic compounds, which influence their chemistry, Secondary particles derive from the oxidation of primary gases such as sulfur and nitrogen oxides into sulfuric acid and nitric acid. The gases from which they originate—may have an origin and a natural biogenic origin. In the presence of ammonia, secondary aerosols often take the form of ammonium salts and this is mainly because the presence of sulfate and nitrate causes the aerosols to increase to a size that scatters light effectively. Organic matter can be primary or secondary, the latter part deriving from the oxidation of VOCs. Organic matter influences the atmospheric radiation field by both scattering and absorption, another important aerosol type is elemental carbon, this aerosol type includes strongly light-absorbing material and is thought to yield large positive radiative forcing. Organic matter and elemental carbon together constitute the carbonaceous fraction of aerosols, Secondary organic aerosols, tiny tar balls resulting from combustion products of internal combustion engines, have been identified as a danger to health. The chemical composition of the aerosol directly affects how it interacts with solar radiation, the chemical constituents within the aerosol change the overall refractive index. The refractive index will determine how light is scattered and absorbed. The particles are hygroscopic due to the presence of sulfur, and SO2 is converted to sulfate when high humidity and this causes the reduced visibility and yellow color. Aerosol particles of natural origin tend to have a larger radius than human-produced aerosols such as particle pollution, the false-color maps in the third image on this page show where there are natural aerosols, human pollution, or a mixture of both, monthly. Most of the Southern Hemisphere is covered by ocean, where the largest source of aerosols is natural sea salt from dried sea spray. Because land is concentrated in the Northern Hemisphere, the amount of small aerosols from fires, over land, patches of large-radius aerosols appear over deserts and arid regions, most prominently, the Sahara Desert in north Africa and the Arabian Peninsula, where dust storms are common
5.
Dust
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Dust is fine particles of matter. It generally consists of particles in the atmosphere that come from sources such as soil, dust lifted by weather, volcanic eruptions. House dust mites are present indoors wherever humans live, positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopic arachnids whose primary food is dead skin cells. They and their feces and other allergens they produce are major constituents of house dust and they are generally found on the floor and other surfaces until disturbed. It could take somewhere between twenty minutes and two hours for dust mites to settle back down out of the air, Dust mites are a nesting species that prefers a dark, warm, and humid climate. They flourish in mattresses, bedding, upholstered furniture, and carpets and their feces include enzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within the human body. House dust mites did not become a problem until humans began to use textiles, such as western style blankets and clothing. Atmospheric or wind-borne dust, also known as aeolian dust, comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, Dust in the atmosphere is produced by saltation and sandblasting of sand-sized grains, and it is transported through the troposphere. This airborne dust is considered an aerosol and once in the atmosphere, saharan dust in particular can be transported and deposited as far as the Caribbean and the Amazon basin, and may affect air temperatures, cause ocean cooling, and alter rainfall amounts. Dust in the Middle East has been a historic phenomenon, recently, because of climate change and the escalating process of desertification, the problem has worsened dramatically. As a multi-factor phenomenon, there is not yet a consensus on the sources or potential solutions to the problem. In Iran, the dust is already affecting more than 5 million people directly, in the province of Khuzestan it has led to the severe reduction of air quality. The amount of pollutants in the air has surpassed more than 50 times the normal level several times in a year, recently, initiatives such as Project-Dust have been established to directly study the Middle Eastern dust. Dust kicked up by vehicles traveling on roads may make up 33% of air pollution, road dust consists of deposits of vehicle exhausts and industrial exhausts, particles from tire and brake wear, dust from paved roads or potholes, and dust from construction sites. Road dust is a significant source contributing to the generation and release of particulate matter into the atmosphere. Control of road dust is a significant challenge in urban areas, road dust may be suppressed by mechanical methods like street sweeper vehicles equipped with vacuum cleaners, vegetable oil sprays, or with water sprayers. Improvements in automotive engineering have reduced the amount of PM10s produced by road traffic, coal dust is responsible for the lung disease known as pneumoconiosis, including black lung disease that occurs among coal miners
6.
Pollen
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Pollen is a fine to coarse powdery substance comprising pollen grains which are male microgametophytes of seed plants, which produce male gametes. If pollen lands on a compatible pistil or female cone, it germinates, individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is useful in paleoecology, paleontology, archaeology. Pollen in plants is used for transferring haploid male genetic material from the anther of a flower to the stigma of another in cross-pollination. In a case of self-pollination, this takes place from the anther of a flower to the stigma of the same flower. Pollen itself is not the male gamete, each pollen grain contains vegetative cells and a generative cell. In flowering plants the vegetative tube cell produces the pollen tube, pollen is produced in the microsporangia in the male cone of a conifer or other gymnosperm or in the anthers of an angiosperm flower. Pollen grains come in a variety of shapes, sizes. Pollen grains of pines, firs, and spruces are winged, the smallest pollen grain, that of the forget-me-not, is around 6 µm in diameter. Wind-borne pollen grains can be as large as about 90–100 µm, in angiosperms, during flower development the anther is composed of a mass of cells that appear undifferentiated, except for a partially differentiated dermis. As the flower develops, four groups of cells form within the anther. The fertile sporogenous cells are surrounded by layers of cells that grow into the wall of the pollen sac. Some of the cells grow into nutritive cells that supply nutrition for the microspores that form by meiotic division from the sporogenous cells, in a process called microsporogenesis, four haploid microspores are produced from each diploid sporogenous cell, after meiotic division. After the formation of the four microspores, which are contained by callose walls, the exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive, in simultaneous microsporogenesis meiotic steps I and II are completed prior to cytokinesis, whereas in successive microsporogenesis cytokinesis follows. While there may be a continuum with intermediate forms, the type of microsporogenesis has systematic significance, the predominant form amongst the monocots is successive, but there are important exceptions. During microgametogenesis, the unicellular microspores undergo mitosis and develop into mature microgametophytes containing the gametes, in some flowering plants, germination of the pollen grain may begin even before it leaves the microsporangium, with the generative cell forming the two sperm cells. Except in the case of submerged aquatic plants, the mature pollen grain has a double wall
7.
Mold
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A mold or mould is a fungus that grows in the form of multicellular filaments called hyphae. In contrast, fungi that can adopt a single-celled growth habit are called yeasts, molds are a large and taxonomically diverse number of fungal species in which the growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism, the hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls may delimit connected compartments along the hyphae, each containing one or multiple, the dusty texture of many molds is caused by profuse production of asexual spores formed by differentiation at the ends of hyphae. The mode of formation and shape of spores is traditionally used to classify molds. Many of these spores are colored, making the much more obvious to the human eye at this stage in its life-cycle. Molds are considered to be microbes and do not form a taxonomic or phylogenetic grouping. In the past, most molds were classified within the Deuteromycota, molds cause biodegradation of natural materials, which can be unwanted when it becomes food spoilage or damage to property. They also play important roles in biotechnology and food science in the production of foods, beverages, antibiotics, pharmaceuticals. There are thousands of species of molds, which have diverse life-styles including saprotrophs, mesophiles, psychrophiles and thermophiles. They all require moisture for growth and some live in aquatic environments, like all fungi, molds derive energy not through photosynthesis but from the organic matter on which they live, utilising heterotrophy. Typically, molds secrete hydrolytic enzymes, mainly from the hyphal tips and these enzymes degrade complex biopolymers such as starch, cellulose and lignin into simpler substances which can be absorbed by the hyphae. In this way molds play a role in causing decomposition of organic material. Many molds also synthesise mycotoxins and siderophores which, together with lytic enzymes, molds can also grow on stored food for animals and humans, making the food unpalatable or toxic and are thus a major source of food losses and illness. Many strategies for food preservation are to prevent or slow growth as well as growth of other microbes. Molds reproduce by producing large numbers of spores, which may contain a single nucleus or be multinucleate. Mold spores can be asexual or sexual, many species can produce both types, other mold spores have slimy sheaths and are more suited to water dispersal. Mold spores are spherical or ovoid single cells, but can be multicellular
8.
Bacteria
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Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
9.
Atmosphere of Earth
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The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earths gravity. The atmosphere of Earth protects life on Earth by absorbing solar radiation, warming the surface through heat retention. By volume, dry air contains 78. 09% nitrogen,20. 95% oxygen,0. 93% argon,0. 04% carbon dioxide, and small amounts of other gases. Air also contains an amount of water vapor, on average around 1% at sea level. The atmosphere has a mass of about 5. 15×1018 kg, the atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km, or 1. 57% of Earths radius, is used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km, several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition. The study of Earths atmosphere and its processes is called atmospheric science, early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann. The three major constituents of air, and therefore of Earths atmosphere, are nitrogen, oxygen, water vapor accounts for roughly 0. 25% of the atmosphere by mass. The remaining gases are often referred to as gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide. Filtered air includes trace amounts of other chemical compounds. Various industrial pollutants also may be present as gases or aerosols, such as chlorine, fluorine compounds, sulfur compounds such as hydrogen sulfide and sulfur dioxide may be derived from natural sources or from industrial air pollution. In general, air pressure and density decrease with altitude in the atmosphere, however, temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions. In this way, Earths atmosphere can be divided into five main layers, excluding the exosphere, Earth has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere. It extends from the exobase, which is located at the top of the thermosphere at an altitude of about 700 km above sea level, to about 10,000 km where it merges into the solar wind. This layer is composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen. The atoms and molecules are so far apart that they can travel hundreds of kilometers without colliding with one another, thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space. These free-moving particles follow ballistic trajectories and may migrate in and out of the magnetosphere or the solar wind, the exosphere is located too far above Earth for any meteorological phenomena to be possible
10.
Absorption (chemistry)
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In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – gas, liquid or solid material. This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, a more general term is sorption, which covers absorption, adsorption, and ion exchange. Absorption is a condition in which something takes in another substance, for some examples of this effect, see liquid-liquid extraction. It is possible to extract from one phase to another a solute without a chemical reaction. Examples of such solutes are noble gases and osmium tetroxide, the process of absorption means that a substance captures and transforms energy. The absorbent distributes the material it captures throughout whole and adsorbent only distributes it through the surface and this equation is valid if concentrations are not too large and if the species x does not change its form in any of the two phases 1 or 2. In the case of gas absorption, one may calculate its concentration by using, e. g. the Ideal gas law, in alternative fashion, one may use partial pressures instead of concentrations. Absorption is a process that may be chemical or physical, chemical absorption or reactive absorption is a chemical reaction between the absorbed and the absorbing substances. Sometimes it combines with physical absorption and this type of absorption depends upon the stoichiometry of the reaction and the concentration of its reactants
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