145-485: Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis , together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires (including stoves , candles , internal combustion engines , oil lamps , and fireplaces ), but may also be used for pest control ( fumigation ), communication ( smoke signals ), defensive and offensive capabilities in
290-520: A diameter of 10 micrometers (μm) or less; fine particles, designated PM 2.5 , 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 (other than ultra-fines ) of air pollution as they can penetrate deep into the lungs and brain from blood streams, causing health problems such as heart disease , lung disease , cancer and preterm birth . There
435-502: A climate feedback) by the IPCC due to the interdependence between it and the hydrological cycle. However, it has previously been classified as a negative radiative forcing. Sulfate aerosols are mostly inorganic sulfur compounds like (SO 4 ),HSO 4 and H 2 SO 4 , which are mainly produced when sulfur dioxide reacts with water vapor to form gaseous sulfuric acid and various salts (often through an oxidation reaction in
580-522: A completely enclosed system or facility, and fit any vent or exhaust with an effective fabric filter or equivalent air pollution control system or equipment, enclose the scaffolding of the building with dust screens, use impervious sheeting to enclose both material hoist and debris chute, wet debris with water before it is dumped into a debris chute, have water sprayed on the facade surface before and during grinding work, use grinder equipped with vacuum cleaner for facade grinding work, spray water continuously on
725-481: A component of ambient air pollution due to the burning of coal in power plants, forest fires or other sources, although the concentration of pollutants in ambient air is typically much less than that in cigarette smoke. One day of exposure to PM2.5 at a concentration of 880 μg/m, such as occurs in Beijing, China, is the equivalent of smoking one or two cigarettes in terms of particulate inhalation by weight. The analysis
870-438: A conductive layer on the circuits can cause crosstalks and other deteriorations of the operating parameters or even cause short circuits and total failures. Electrical contacts can be affected by corrosion of surfaces, and by deposition of soot and other conductive particles or nonconductive layers on or across the contacts. Deposited particles may adversely affect the performance of optoelectronics by absorbing or scattering
1015-627: A danger to health. Particulate toxicity has been found to vary by region and source contribution which affects the particles chemical composition. 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 much light is scattered and absorbed. The composition of particulate matter that generally causes visual effects, haze , consists of sulfur dioxide, nitrogen oxides, carbon monoxide, mineral dust, and organic matter. The particles are hygroscopic due to
1160-516: A density of about 2200 kg/m and a melting point of 600 K (327 °C; 620 °F). It maintains high strength, toughness and self-lubrication at low temperatures down to 5 K (−268.2 °C; −450.7 °F), and good flexibility at temperatures above 194 K (−79.15 °C; −110.5 °F). PTFE gains its properties from the aggregate effect of carbon-fluorine bonds , as do all fluorocarbons. The only chemicals known to affect these carbon-fluorine bonds are highly reactive metals like
1305-410: A first step or "pre-cleaner" to other more efficient collectors. Well-designed cyclonic separators can be very efficient in removing even fine particulates, and may be operated continuously without requiring frequent shutdowns for maintenance. Fabric filters or baghouses are the most commonly employed in general industry. They work by forcing dust-laden air through a bag-shaped fabric filter leaving
1450-523: A global mean radiative forcing of +0.2 W/m (was +0.1 W/m in the Second Assessment Report of the IPCC, SAR), with a range +0.1 to +0.4 W/m . A study published in 2013 however, states that "the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W/m with 90% uncertainty bounds of (+0.08, +1.27) W/m " with "total direct forcing by all-black carbon sources, without subtracting
1595-537: A good indication of the levels of smoke. Indeed, several jurisdictions use CO measurement as the basis of smoke control . However it is far from clear how accurate the correspondence is. Throughout recorded history, humans have used the smoke of medicinal plants to cure illness. A sculpture from Persepolis shows Darius the Great (522–486 BC), the king of Persia , with two censers in front of him for burning Peganum harmala and/or sandalwood Santalum album , which
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#17327730788581740-562: A high sulfur content, primarily coal and certain less-refined fuels, like aviation and bunker fuel , had dominated. By 1990, global human-caused emissions of sulfur into the atmosphere became "at least as large" as all natural emissions of sulfur-containing compounds combined , and were at least 10 times more numerous than the natural aerosols in the most polluted regions of Europe and North America, where they accounted for 25% or more of all air pollution. This led to acid rain , and also contributed to heart and lung conditions and even
1885-696: A large amount of hydrocarbons , both aliphatic ( methane , ethane , ethylene , acetylene ) and aromatic ( benzene and its derivates, polycyclic aromatic hydrocarbons ; e.g. benzo[a]pyrene , studied as a carcinogen, or retene ), terpenes . It also results in the emission of a range of smaller oxygenated volatile organic compounds ( methanol , acetic acid , hydroxy acetone , methyl acetate and ethyl formate ) which are formed as combustion by products as well as less volatile oxygenated organic species such as phenolics, furans and furanones . Heterocyclic compounds may be also present. Heavier hydrocarbons may condense as tar ; smoke with significant tar content
2030-408: A lingering odor even long after the fire. Partial oxidation of the released hydrocarbons yields in a wide palette of other compounds: aldehydes (e.g. formaldehyde , acrolein , and furfural ), ketones, alcohols (often aromatic, e.g. phenol , guaiacol , syringol , catechol , and cresols ), carboxylic acids ( formic acid , acetic acid , etc.). The visible particulate matter in such smokes
2175-591: A material to coat valves and seals in the pipes holding highly reactive uranium hexafluoride at the vast K-25 uranium enrichment plant in Oak Ridge, Tennessee . In 1954, Colette Grégoire urged her husband, the French engineer Marc Grégoire, to try the material he had been using on fishing tackle on her cooking pans. He subsequently created the first PTFE-coated, non-stick pans under the brand name Tefal (combining "Tef" from "Teflon" and "al" from aluminium). In
2320-645: A minimal loss of performance over the lifetime of the gasket. PTFE is an ultraviolet (UV) transparent polymer. However, when exposed to an excimer laser beam it severely degrades due to heterogeneous photothermal effect . Processing PTFE can be difficult and expensive because its high melting temperature, 327 °C (621 °F), is above its decomposition temperature. Even when molten, PTFE does not flow due to its exceedingly high melt-viscosity. The viscosity and melting point can be decreased by inclusion of small amount of comonomers such as perfluoro (propylvinyl ether) and hexafluoropropylene (HFP). These cause
2465-562: A mixture of both, monthly. The size distribution time series shows that in the planet's most southerly latitudes, nearly all the aerosols are large, but in the high northern latitudes, smaller aerosols are very abundant. Most of the Southern Hemisphere is covered by the ocean, where the largest source of aerosols is natural sea salt from dried sea spray. Because the land is concentrated in the Northern Hemisphere,
2610-426: A net negative radiative forcing. The magnitude of the resultant radiative forcing due to the direct effect of an aerosol is dependent on the albedo of the underlying surface, as this affects the net amount of radiation absorbed or scattered to space. For example, if a highly scattering aerosol is above a surface of low albedo it has a greater radiative forcing than if it was above a surface of high albedo. The converse
2755-408: A particle. The SSA tends to unity if scattering dominates, with relatively little absorption, and decreases as absorption increases, becoming zero for infinite absorption. For example, the sea-salt aerosol has an SSA of 1, as a sea-salt particle only scatters, whereas soot has an SSA of 0.23, showing that it is a major atmospheric aerosol absorber. The Indirect aerosol effect consists of any change to
2900-488: A potent carcinogen , and other polychlorinated dibenzodioxins . Pyrolysis of fluoropolymers, e.g. teflon , in presence of oxygen yields carbonyl fluoride (which hydrolyzes readily to HF and CO 2 ); other compounds may be formed as well, e.g. carbon tetrafluoride , hexafluoropropylene , and highly toxic perfluoroisobutene (PFIB). Pyrolysis of burning material, especially incomplete combustion or smoldering without adequate oxygen supply, also results in production of
3045-432: A range of other psychosocial problems. As early as the 15th century Leonardo da Vinci commented at length on the difficulty of assessing smoke, and distinguished between black smoke (carbonized particles) and white 'smoke' which is not a smoke at all but merely a suspension of harmless water particulates. Smoke from heating appliances is commonly measured in one of the following ways: In-line capture. A smoke sample
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#17327730788583190-772: A regional scale. The failure of the Indian monsoon has been linked to the suppression of evaporation of water from the Indian Ocean due to the semi-direct effect of anthropogenic aerosol. Recent studies of the Sahel drought and major increases since 1967 in rainfall in Australia over the Northern Territory , Kimberley , Pilbara and around the Nullarbor Plain have led some scientists to conclude that
3335-1012: A significantly wider palette of compounds, many of them toxic. Partial oxidation of carbon produces carbon monoxide , while nitrogen-containing materials can yield hydrogen cyanide , ammonia , and nitrogen oxides. Hydrogen gas can be produced instead of water. Contents of halogens such as chlorine (e.g. in polyvinyl chloride or brominated flame retardants ) may lead to the production of hydrogen chloride , phosgene , dioxin , and chloromethane , bromomethane and other halocarbons . Hydrogen fluoride can be formed from fluorocarbons , whether fluoropolymers subjected to fire or halocarbon fire suppression agents . Phosphorus and antimony oxides and their reaction products can be formed from some fire retardant additives, increasing smoke toxicity and corrosivity. Pyrolysis of polychlorinated biphenyls (PCB), e.g. from burning older transformer oil , and to lower degree also of other chlorine-containing materials, can produce 2,3,7,8-tetrachlorodibenzodioxin ,
3480-472: A single instrument and apply an algorithm to give a good estimate of smoke. It has been claimed that these devices can differentiate types of smoke and so their probable source can be inferred, though this is disputed. Inference from carbon monoxide . Smoke is incompletely burned fuel , carbon monoxide is incompletely burned carbon, therefore it has long been assumed that measurement of CO in flue gas (a cheap, simple and very accurate procedure) will provide
3625-583: A single mass. The most common use of PTFE, consuming about 50% of production, is for the insulation of wiring in aerospace and computer applications (e.g. hookup wire, coaxial cables). This application exploits the fact that PTFE has excellent dielectric properties, specifically low group velocity dispersion , especially at high radio frequencies , making it suitable for use as an excellent insulator in connector assemblies and cables , and in printed circuit boards used at microwave frequencies. Combined with its high melting temperature, this makes PTFE
3770-401: A smoky odor. Just as there are contractors that specialize in rebuilding/repairing homes that have been damaged by fire and smoke, fabric restoration companies specialize in restoring fabrics that have been damaged in a fire. Smoke from oxygen-deprived fires contains a significant concentration of compounds that are flammable. A cloud of smoke, in contact with atmospheric oxygen, therefore has
3915-399: A standard in many countries. Optical scattering. A light beam is passed through the smoke. A light detector is situated at an angle to the light source, typically at 90°, so that it receives only light reflected from passing particles. A measurement is made of the light received which will be higher as the concentration of smoke particles becomes higher. Optical obscuration. A light beam
4060-401: A surfactant is the primary means of keeping PTFE in an aqueous medium. Surfactants in the past have included toxic perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). More recently, Perfluoro 3,6 dioxaoctanoic acid (PFO2OA) and FRD-903 (GenX) are being used as alternative surfactants. PTFE is a thermoplastic polymer , which is a white solid at room temperature, with
4205-406: A weight differential in his test cylinder, brought it to the attention of Roy Plunkett. The chemists in the lab sawed the bottle apart and found the bottle's interior coated with a waxy white material that was oddly slippery. Analysis showed that it was polymerized perfluoroethylene, with the iron from the inside of the container having acted as a catalyst at high pressure. Kinetic Chemicals patented
4350-433: Is hydrophobic : neither water nor water-containing substances wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low electric polarizability of fluorine. PTFE has one of the lowest coefficients of friction of any solid. Polytetrafluoroethylene is used as a non-stick coating for pans and other cookware. It is non-reactive, partly because of the strength of carbon–fluorine bonds , so it
4495-535: Is a brand of expanded PTFE (ePTFE), a material incorporating a fluoropolymer membrane with micropores. The roof of the Hubert H. Humphrey Metrodome in Minneapolis , US, was one of the largest applications of PTFE coatings. 20 acres (81,000 m ) of the material was used in the creation of the white double-layered PTFE-coated fiberglass dome. Because of its extreme non-reactivity and high temperature rating, PTFE
Smoke - Misplaced Pages Continue
4640-431: Is a concern especially for internal combustion engines . Molten sulfate and lead particulates also have such effect. Some components of smoke are characteristic of the combustion source. Guaiacol and its derivatives are products of pyrolysis of lignin and are characteristic of wood smoke; other markers are syringol and derivates, and other methoxy phenols . Retene , a product of pyrolysis of conifer trees,
4785-503: Is a first order effect and therefore classified as a radiative forcing by the IPCC . An increase in cloud droplet number due to the introduction of aerosol acts to reduce the cloud droplet size, as the same amount of water is divided into more droplets. This has the effect of suppressing precipitation, increasing the cloud lifetime, known as the cloud lifetime aerosol effect, second indirect effect or Albrecht effect. This has been observed as
4930-430: Is a synthetic fluoropolymer of tetrafluoroethylene , and has numerous applications because it is chemically inert . The commonly known brand name of PTFE-based composition is Teflon by Chemours , a spin-off from DuPont , which originally discovered the compound in 1938. Polytetrafluoroethylene is a fluorocarbon solid, as it is a high- molecular-weight polymer consisting wholly of carbon and fluorine . PTFE
5075-428: Is also dependent upon air flow rates and the partial pressure of the gases in the inspired air. The fate of a specific contaminant is dependent upon the form in which it exists (aerosol or particulate). Inhalation also depends upon the breathing rate of the subject. Another complexity not entirely documented is how the shape of PM can affect health, except for the needle-like shape of asbestos fibres which can lodge in
5220-761: Is an aerosol (or mist ) of solid particles and liquid droplets that are close to the ideal range of sizes for Mie scattering of visible light . The composition of smoke depends on the nature of the burning fuel and the conditions of combustion. Fires with high availability of oxygen burn at a high temperature and with a small amount of smoke produced; the particles are mostly composed of ash , or with large temperature differences, of condensed aerosol of water. High temperature also leads to production of nitrogen oxides . Sulfur content yields sulfur dioxide , or in case of incomplete combustion, hydrogen sulfide . Carbon and hydrogen are almost completely oxidized to carbon dioxide and water. Fires burning with lack of oxygen produce
5365-600: Is an indicator of forest fires . Levoglucosan is a pyrolysis product of cellulose . Hardwood vs softwood smokes differ in the ratio of guaiacols/syringols. Markers for vehicle exhaust include polycyclic aromatic hydrocarbons , hopanes , steranes , and specific nitroarenes (e.g. 1-nitropyrene ). The ratio of hopanes and steranes to elemental carbon can be used to distinguish between emissions of gasoline and diesel engines. Many compounds can be associated with particulates; whether by being adsorbed on their surfaces, or by being dissolved in liquid droplets. Hydrogen chloride
5510-550: Is applied across the tubes and wires so that the smoke particles become charged and are attracted to the sides of the tubes. This method can over-read by capturing harmless condensates, or under-read due to the insulating effect of the smoke. However, it is the necessary method for assessing volumes of smoke too great to be forced through a filter, i.e., from bituminous coal . Ringelmann scale . A measure of smoke color. Invented by Professor Maximilian Ringelmann in Paris in 1888, it
5655-409: Is classified as the direct effect. It encompasses many individual mechanisms, and in general is more poorly defined and understood than the direct and indirect aerosol effects. For instance, if absorbing aerosols are present in a layer aloft in the atmosphere, they can heat surrounding air which inhibits the condensation of water vapour, resulting in less cloud formation. Additionally, heating a layer of
5800-526: Is complicated, however, by the fact that the organic compounds present in various ambient particulates may have a higher carcinogenicity than the compounds in cigarette smoke particulates. Secondhand tobacco smoke is the combination of both sidestream and mainstream smoke emissions from a burning tobacco product. These emissions contain more than 50 carcinogenic chemicals. According to the United States Surgeon General 's 2006 report on
5945-596: Is composed mainly of silica and calcium oxide . Cenospheres are present in smoke from liquid hydrocarbon fuels. Minute metal particles produced by abrasion can be present in engine smokes. Amorphous silica particles are present in smokes from burning silicones ; small proportion of silicon nitride particles can be formed in fires with insufficient oxygen. The silica particles have about 10 nm size, clumped to 70–100 nm aggregates and further agglomerated to chains. Radioactive particles may be present due to traces of uranium , thorium , or other radionuclides in
Smoke - Misplaced Pages Continue
6090-483: Is composed of pure carbon clusters, skeleton balls and fullerenes , and is one of the most important absorbing aerosol species in the atmosphere. It should be distinguished from organic carbon (OC): clustered or aggregated organic molecules on their own or permeating an EC buckyball. Black carbon from fossil fuels is estimated by the IPCC in the Fourth Assessment Report of the IPCC, 4AR, to contribute
6235-586: Is considered a minor exposure pathway to PFOA. As a result of the lawsuits concerning the PFOA class-action lawsuit , DuPont began to use GenX, a similarly fluorinated compound, as a replacement for perfluorooctanoic acid in the manufacture of fluoropolymers , such as Teflon-brand PTFE. However, the EPA has classified GenX as more toxic than PFOA and it has proven to be a “regrettable substitute”; its effects may be equally harmful or even more detrimental than those of
6380-478: Is essentially a card with squares of black, white and shades of gray which is held up and the comparative grayness of the smoke judged. Highly dependent on light conditions and the skill of the observer it allocates a grayness number from 0 (white) to 5 (black) which has only a passing relationship to the actual quantity of smoke. Nonetheless, the simplicity of the Ringelmann scale means that it has been adopted as
6525-672: Is highest near the source of emission. Any information regarding DPM and the atmosphere, flora, height, and distance from major sources is useful to determine health effects. Particulate matter emissions are highly regulated in most industrialized countries. Due to environmental concerns , most industries are required to operate some kind of dust collection system. These systems include inertial collectors ( cyclonic separators ), fabric filter collectors (baghouses) , electrostatic filters used in facemasks, wet scrubbers , and electrostatic precipitators . Cyclonic separators are useful for removing large, coarse particles and are often employed as
6670-727: Is mainly because the presence of sulfate and nitrate causes the aerosols to increase to a size that scatters light effectively. Organic matter (OM) found in aerosols can be either primary or secondary, the latter part deriving from the oxidation of volatile organic compounds (VOCs); organic material in the atmosphere may either be biogenic or anthropogenic . Organic matter influences the atmospheric radiation field by both scattering and absorption. Some aerosols are predicted to include strongly light-absorbing material and are thought to yield large positive radiative forcing . Some secondary organic aerosols (SOAs) resulting from combustion products of internal combustion engines, have been identified as
6815-449: Is most commonly composed of carbon ( soot ). Other particulates may be composed of drops of condensed tar, or solid particles of ash. The presence of metals in the fuel yields particles of metal oxides . Particles of inorganic salts may also be formed, e.g. ammonium sulfate , ammonium nitrate , or sodium chloride . Inorganic salts present on the surface of the soot particles may make them hydrophilic . Many organic compounds, typically
6960-907: Is no longer being made in the United States. PTFE was added to the Living Building Challenge (LBC) Red List in 2016. The Red List bans substances prevalent in the building industry that pose serious risks to human health and the environment from construction that seeks to meet the criteria of the Living Building Challenge (LBC). Sodium trifluoroacetate and the similar compound sodium chlorodifluoroacetate can both be generated when PTFE undergoes thermolysis , as well as producing longer chain polyfluoro- and/or polychlorofluoro- (C3-C14) carboxylic acids which may be equally persistent. These products can accumulate in evaporative wetlands and have been found in
7105-851: Is no safe level of particulates. Worldwide, exposure to PM 2.5 contributed to 4.1 million deaths from heart disease, stroke, lung cancer, chronic lung disease, and respiratory infections in 2016. Overall, ambient particulate matter is one of the leading risk factor for premature death globally. Human activities generate significant amounts of particulates. For example: Some types of dust, e.g., ashes , soot , paint , glass , plastic and dust from certain man-made fibres, which are brittle and break easily (can fragment and "proliferate"), can pose greater threats and irritations to humans. Those with sharp edges may be even more problematic. The number, shapes, stickiness, etc. of particulates may also be altered by different meteorological conditions. Human-made (anthropogenic) aerosols account for about 10 percent of
7250-503: Is not significant for structural materials, but delicate structures, especially microelectronics , are strongly affected. Corrosion of circuit board traces, penetration of aggressive chemicals through the casings of parts, and other effects can cause an immediate or gradual deterioration of parameters or even premature (and often delayed, as the corrosion can progress over long time) failure of equipment subjected to smoke. Many smoke components are also electrically conductive ; deposition of
7395-568: Is notable for its extremely low coefficient of friction, its hydrophobia (which serves to inhibit rust), and for the dry film it forms after application, which allows it to resist collecting particles that might otherwise form an abrasive paste. Brands include GT85, Tri-Flow and WD-40 Specialist. PTFE is best known for its use in coating non-stick frying pans and other cookware, as it is hydrophobic and possesses fairly high heat resistance. The sole plates of some clothes irons are coated with PTFE. Other niche applications include: While PTFE
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#17327730788587540-403: Is often used as the liner in hose assemblies, expansion joints , and in industrial pipe lines, particularly in applications using acids, alkalis, or other chemicals. Its frictionless qualities allow improved flow of highly viscous liquids and for uses in applications such as brake hoses. PTFE architectural membranes are created by coating a woven glass-fibre base cloth with PTFE, forming one of
7685-669: Is often used in containers and pipework for reactive and corrosive chemicals. Where used as a lubricant , PTFE reduces friction, wear, and energy consumption of machinery. It is used as a graft material in surgery and as a coating on catheters . PTFE and chemicals used in its production are some of the best-known and widely applied PFAS , which are persistent organic pollutants . PTFE occupies more than half of all fluoropolymer production, followed by polyvinylidene fluoride (PVdF) . For decades, DuPont used perfluorooctanoic acid (PFOA, or C8) during production of PTFE, later discontinuing its use due to legal actions over ecotoxicological and
7830-402: Is passed through the smoke and a detector opposite measures the light. The more smoke particles are present between the two, the less light will be measured. Combined optical methods. There are various proprietary optical smoke measurement devices such as the ' nephelometer ' or the ' aethalometer ' which use several different optical methods, including more than one wavelength of light, inside
7975-449: Is present in emissions from oil fired power plants and refineries ; oil plants also emit some nickel . Coal combustion produces emissions containing aluminium , arsenic , chromium , cobalt , copper , iron , mercury , selenium , and uranium . Traces of vanadium in high-temperature combustion products form droplets of molten vanadates . These attack the passivation layers on metals and cause high temperature corrosion , which
8120-871: Is responsible for nearly half (43%) of annual PAH lung cancer-risk compared to the other sources and that wintertime PAH levels were 7 times higher than in other seasons, presumably due to an increased use of fireplaces and heaters. The largest exposure events are periods during the winter with reduced atmospheric dispersion to dilute the accumulated pollution, in particular due to the low wind speeds. Research conducted about biomass burning in 2015, estimated that 38% of European total particulate pollution emissions are composed of domestic wood burning. Wood smoke (for example from wildfires or wood ovens) can cause lung damage, artery damage and DNA damage leading to cancer, other respiratory and lung disease and cardiovascular disease. Air pollution, particulate matter and wood smoke may also cause brain damage because of particulates breaching
8265-417: Is simply sucked through a filter which is weighed before and after the test and the mass of smoke found. This is the simplest and probably the most accurate method, but can only be used where the smoke concentration is slight, as the filter can quickly become blocked. The ASTM smoke pump is a simple and widely used method of in-line capture where a measured volume of smoke is pulled through a filter paper and
8410-439: Is stable at lower temperatures, it begins to deteriorate at temperatures of about 260 °C (500 °F), it decomposes above 350 °C (662 °F), and pyrolysis occurs at temperatures above 400 °C (752 °F). The main decomposition products are fluorocarbon gases and a sublimate , including tetrafluoroethylene (TFE) and difluorocarbene radicals (RCF2). An animal study conducted in 1955 concluded that it
8555-528: Is the largest single source of PM2.5 annually. In some towns and cities in New South Wales , wood smoke may be responsible for 60% of fine particle air pollution in the winter. A year-long sampling campaign in Athens, Greece found a third (31%) of PAH urban air pollution to be caused by wood-burning, roughly as much as that of diesel and oil (33%) and gasoline (29%). It also found that wood-burning
8700-445: Is true of absorbing aerosol, with the greatest radiative forcing arising from a highly absorbing aerosol over a surface of high albedo. The direct aerosol effect is a first-order effect and is therefore classified as a radiative forcing by the IPCC . The interaction of an aerosol with radiation is quantified by the single-scattering albedo (SSA), the ratio of scattering alone to scattering plus absorption ( extinction ) of radiation by
8845-440: Is typically initiated with persulfate , which homolyzes to generate sulfate radicals: The resulting polymer is terminated with sulfate ester groups, which can be hydrolyzed to give OH end-groups . Granular PTFE is produced via suspension polymerization, where PTFE is suspended in an aqueous medium primarily via agitation and sometimes with the use of a surfactant. PTFE is also synthesized via emulsion polymerization, where
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#17327730788588990-571: Is unlikely that these products would be generated in amounts significant to health at temperatures below 250 °C (482 °F). Above those temperatures the degradation by-products can be lethal to birds , and can cause flu-like symptoms in humans ( polymer fume fever ), although in humans those symptoms disappear within a day or two of being moved to fresh air. Most cases of polymer fume fever in humans occur due to smoking PTFE-contaminated tobacco, although cases have occurred in people who have welded near PTFE components. PTFE-coated cookware
9135-434: Is unlikely to reach dangerous temperatures with normal use, as meat is usually fried between 204 and 232 °C (399 and 450 °F), and most cooking oils (except refined safflower and avocado oils) start to smoke before a temperature of 260 °C (500 °F) is reached. A 1973 study by DuPont's Haskell Laboratory found that a 4-hour exposure to the fumes emitted by PTFE cookware heated to 280 °C (536 °F)
9280-500: Is usually measured against polished steel. PTFE's coefficient of friction is 0.05 to 0.10, which is the third-lowest of any known solid material ( aluminium magnesium boride (BAM) being the lowest, with a coefficient of friction of 0.02; diamond-like carbon being second-lowest at 0.05). PTFE's resistance to van der Waals forces means that it is the only known surface to which a gecko cannot stick. In addition, PTFE can be used to prevent insects from climbing up surfaces painted with
9425-455: Is well absorbed in the soot particles. Inert particulate matter can be disturbed and entrained into the smoke. Of particular concern are particles of asbestos . Deposited hot particles of radioactive fallout and bioaccumulated radioisotopes can be reintroduced into the atmosphere by wildfires and forest fires ; this is a concern in e.g. the Zone of alienation containing contaminants from
9570-466: Is why clothing, unsealed surfaces, potable water, piping, wood, etc., are replaced in most cases of structural fires. Wood smoke is a major source of air pollution , especially particulate pollution , pollution by polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) such as formaldehyde . In the United Kingdom domestic combustion, especially for industrial uses,
9715-674: Is yellow to brown. Combustion of solid fuels can result in the emission of many hundreds to thousands of lower volatility organic compounds in the aerosol phase. Presence of such smoke, soot, and/or brown oily deposits during a fire indicates a possible hazardous situation, as the atmosphere may be saturated with combustible pyrolysis products with concentration above the upper flammability limit , and sudden inrush of air can cause flashover or backdraft . Presence of sulfur can lead to formation of gases like hydrogen sulfide, carbonyl sulfide , sulfur dioxide, carbon disulfide , and thiols ; especially thiols tend to get adsorbed on surfaces and produce
9860-596: The Chernobyl disaster . Polymers are a significant source of smoke. Aromatic side groups , e.g. in polystyrene , enhance generation of smoke. Aromatic groups integrated in the polymer backbone produce less smoke, likely due to significant charring . Aliphatic polymers tend to generate the least smoke, and are non-self-extinguishing. However presence of additives can significantly increase smoke formation. Phosphorus-based and halogen-based flame retardants decrease production of smoke. Higher degree of cross-linking between
10005-476: The alkali metals , at higher temperatures such metals as aluminium and magnesium, and fluorinating agents such as xenon difluoride and cobalt(III) fluoride . At temperatures above 650–700 °C (1,200–1,290 °F) PTFE undergoes depolymerization. However, it begins to decompose at about 260 °C (500 °F) through 350 °C (662 °F), and pyrolysis occurs at temperatures above 400 °C (752 °F). The coefficient of friction of plastics
10150-462: The aromatic hydrocarbons , may be also adsorbed on the surface of the solid particles. Metal oxides can be present when metal-containing fuels are burned, e.g. solid rocket fuels containing aluminium . Depleted uranium projectiles after impacting the target ignite, producing particles of uranium oxides . Magnetic particles, spherules of magnetite -like ferrous ferric oxide , are present in coal smoke; their increase in deposits after 1860 marks
10295-485: The clouds ), which are then thought to experience hygroscopic growth and coagulation and then shrink through evaporation . Some of them are biogenic (typically produced via atmospheric chemical reactions with dimethyl sulfide from mostly marine plankton ) or geological via volcanoes or weather-driven from wildfires and other natural combustion events, but in the recent decades anthropogenic sulfate aerosols produced through combustion of fossil fuels with
10440-460: The electrostatic analogues of permanent magnets . PTFE film is also widely used in the production of carbon fiber composites as well as fiberglass composites, notably in the aerospace industry. PTFE film is used as a barrier between the carbon or fiberglass part being built and, in breather and bagging materials, is used to incapsulate the bondment when debulking (vacuum removal of air from between layers of laid-up plies of material) and when curing
10585-438: The health effects of exposure to PFOA . Dupont's spin-off Chemours today manufactures PTFE using an alternative chemical it calls GenX , another PFAS. Although GenX was designed to be less persistent in the environment compared to PFOA, it has proven to be a “regrettable substitute.” Its effects may be equally harmful or even more detrimental than those of the chemical it was meant to replace. Polytetrafluoroethylene (PTFE)
10730-429: The 1990s, PTFE was not known to crosslink like an elastomer , due to its chemical inertness. Therefore, it has no "memory" and is subject to creep . Because of the propensity to creep, the long-term performance of such seals is worse than for elastomers that exhibit zero, or near-zero, levels of creep. In critical applications, Belleville washers are often used to apply continuous force to PTFE gaskets, thereby ensuring
10875-537: The 1990s, it was found that PTFE could be radiation cross-linked above its melting point in an oxygen-free environment. Electron beam processing is one example of radiation processing. Cross-linked PTFE has improved high-temperature mechanical properties and radiation stability. That was significant because, for many years, irradiation at ambient conditions has been used to break down PTFE for recycling. This radiation-induced chain scission allows it to be more easily reground and reused. Corona discharge treatment of
11020-452: The 1991 eruption of Mount Pinatubo which caused a global cooling of approximately 0.5 °C lasting several years. Research tracking the effect of light-scattering aerosols in the stratosphere during 2000 and 2010 and comparing its pattern to volcanic activity show a close correlation. Simulations of the effect of anthropogenic particles showed little influence at present levels. Aerosols are also thought to affect weather and climate on
11165-638: The Earth's radiative budget due to the modification of clouds by atmospheric aerosols and consists of several distinct effects. Cloud droplets form onto pre-existing aerosol particles, known as cloud condensation nuclei (CCN). Droplets condensing around human-produced aerosols such as found in particulate pollution tend to be smaller and more numerous than those forming around aerosol particles of natural origin (such as windblown dust ). For any given meteorological conditions, an increase in CCN leads to an increase in
11310-427: The United States alone. Yet, around the same time, research had shown that sulfate aerosols were affecting both the visible light received by the Earth and its surface temperature , and as the so-called global dimming ) began to reverse in the 1990s in line with the reduced anthropogenic sulfate pollution, climate change accelerated. As of 2021, state-of-the-art CMIP6 models estimate that total cooling from
11455-410: The United States, Marion A. Trozzolo , who had been using the substance on scientific utensils, marketed the first US-made PTFE-coated pan, "The Happy Pan", in 1961. Non-stick cookware has since become a common household product, now offered by hundreds of manufacturers across the world. The brand name Zepel was used for promoting its stain-resistance and water-resistance when applied to fabrics. In
11600-802: The absorption of its active chemical principles. Particulates Particulates or atmospheric particulate matter (see below for other names) are microscopic particles of solid or liquid matter suspended in the air . The term aerosol refers to the particulate/air mixture , 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 . They have impacts on climate and precipitation that adversely affect human health , in ways additional to direct inhalation. Types of atmospheric particles include suspended particulate matter; thoracic and respirable particles; inhalable coarse particles, designated PM 10 , which are coarse particles with
11745-464: The additive effects of hydrogen cyanide and phosgene . Smoke inhalation can therefore quickly lead to incapacitation and loss of consciousness. Sulfur oxides, hydrogen chloride and hydrogen fluoride in contact with moisture form sulfuric , hydrochloric and hydrofluoric acid , which are corrosive to both lungs and materials. Cigarette smoke is a major modifiable risk factor for lung disease , heart disease , and many cancers . Smoke can also be
11890-470: The aerosol haze over South and East Asia has been steadily shifting tropical rainfall in both hemispheres southward. The size of particulate matter (PM) is a key determinant of its potential to cause health problems. Particles of different sizes deposit in different regions of the respiratory tract , leading to various health effects. The particles are grouped by sizes: Particles can cause health effects through several mechanisms: inflammation in
12035-711: The amount of small aerosols from fires and human activities is greater there than in the Southern Hemisphere. Overland, 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. Places where human-triggered or natural fire activity is common (land-clearing fires in the Amazon from August–October, for example, or lightning-triggered fires in
12180-643: The area beginning in 1976 with the production of Nafion, and that PFAS including GenX had been released as a byproduct of the production of Vinyl Ethers since 1980, exposing the Cape Fear Basin for decades. A small nonprofit called Cape Fear River Watch sued NC DEQ for not taking swifter and stronger action, and sued the polluter, Chemours, for violations of the Clean Water Act and the Toxic Substances Control Act. The result
12325-479: The atmosphere relative to the surface results in a more stable atmosphere due to the inhibition of atmospheric convection . This inhibits the convective uplift of moisture, which in turn reduces cloud formation. The heating of the atmosphere aloft also leads to a cooling of the surface, resulting in less evaporation of surface water. The effects described here all lead to a reduction in cloud cover i.e. an increase in planetary albedo. The semi-direct effect classified as
12470-496: The beginning of the Industrial Revolution. (Magnetic iron oxide nanoparticles can be also produced in the smoke from meteorites burning in the atmosphere.) Magnetic remanence , recorded in the iron oxide particles, indicates the strength of Earth's magnetic field when they were cooled beyond their Curie temperature ; this can be used to distinguish magnetic particles of terrestrial and meteoric origin. Fly ash
12615-461: The blood of people who work in or live near factories where the chemical is used, and in people regularly exposed to PFOA-containing products such as some ski waxes and stain-resistant fabric coatings, but non-stick cookware was not found to be a major source of exposure, as the PFOA is burned off during the manufacturing process and not present in the finished product. Non-stick coated cookware has not been manufactured using PFOA since 2013, and PFOA
12760-452: The burning of living and dead vegetation would be different from those emitted from the burning of joss paper or construction wastes . Particles emitted from fuel combustion are not the same as those emitted from waste combustion. The particulate matter generated from the fire of a recycling yard or a ship full of scrap metal may contain more toxic substances than other types of burning. Teflon Polytetrafluoroethylene ( PTFE )
12905-588: The cardiovascular system and into the brain, which can increase the risk of developmental disorders, neurodegenerative disorders mental disorders, and suicidal behavior, although studies on the link between depression and some air pollutants are not consistent. At least one study has identified "the abundant presence in the human brain of magnetite nanoparticles that match precisely the high-temperature magnetite nanospheres, formed by combustion and/or friction-derived heating, which are prolific in urban, airborne particulate matter (PM)." Air pollution has also been linked to
13050-648: The chemical it was meant to replace. The chemicals are manufactured by Chemours , a corporate spin-off of DuPont, in Fayetteville, North Carolina . Fayetteville Works was the site where DuPont began manufacture of PFOA after the lawsuit in Parkersburg WV halted their production there. When EPA asked companies to voluntarily phase out PFOA production, it was replaced by GenX in Fayetteville Works. In June of 2017, The Wilmington Star-News broke
13195-451: The climate of the Earth by changing the amount of incoming solar radiation and outgoing terrestrial longwave radiation retained in the Earth's system. This occurs through several distinct mechanisms which are split into direct, indirect and semi-direct aerosol effects. The aerosol climate effects are the biggest source of uncertainty in future climate predictions. The Intergovernmental Panel on Climate Change (IPCC) stated in 2001: While
13340-424: The composite, usually in an autoclave. The PTFE, used here as a film, prevents the non-production materials from sticking to the part being built, which is sticky due to the carbon-graphite or fiberglass plies being pre-pregnated with bismaleimide resin. Non-production materials such as Teflon, Airweave Breather, and the bag itself would be considered F.O.D. (foreign object debris/damage) if left in layup. Gore-Tex
13485-473: The composition of sea water , and thus include magnesium , sulfate , calcium , potassium , and others. In addition, sea spray aerosols may contain organic compounds like fatty acids and sugars, which influence their chemistry. Some secondary particles derive from the oxidation of primary gases such as sulfur and nitrogen oxides into sulfuric acid (liquid) and nitric acid (gaseous) or from biogenic emissions. The precursors for these aerosols—i.e.
13630-457: The cooling from sulfate pollution while minimizing the negative effects on health through deploying in the stratosphere , where only a fraction of the current sulfur pollution would be needed to avoid multiple degrees of warming, but the assessment of costs and benefits remains incomplete, even with hundreds of studies into the subject completed by the early 2020s. Black carbon (BC), or carbon black, or elemental carbon (EC), often called soot,
13775-560: The currently present aerosols is between 0.1 °C (0.18 °F) to 0.7 °C (1.3 °F); the IPCC Sixth Assessment Report uses the best estimate of 0.5 °C (0.90 °F), with the uncertainty mainly caused by contradictory research on the impacts of aerosols of clouds . Some are certain that they cool the planet, though, and this led to solar geoengineering proposals known as stratospheric aerosol injection , which seeks to replicate and enhance
13920-456: The dark spot so formed is compared with a standard. Filter/dilution tunnel. A smoke sample is drawn through a tube where it is diluted with air, the resulting smoke/air mixture is then pulled through a filter and weighed. This is the internationally recognized method of measuring smoke from combustion . Electrostatic precipitation. The smoke is passed through an array of metal tubes which contain suspended wires. A (huge) electrical potential
14065-507: The dirty air through a scrubbing solution (usually a mixture of water and other compounds) allowing the particulate to attach to the liquid molecules. Electrostatic precipitators electrically charge the dirty air as it passes through. The now charged air then passes through large electrostatic plates which attract the charged particle in the airstream collecting them and leaving the now clean air to be exhausted or recirculated. For general building construction, some places that have acknowledged
14210-466: The early 20th century. The earliest methods included relatively crude Ringelmann charts , which were grey-shaded cards against which emissions from smokestacks could be visually compared, and deposit gauges , which collected the soot deposited in a particular location so it could be weighed. Automated, modern methods of measuring particulates include optical photodetectors , tapered element oscillating microbalances , and Aethalometers . Besides measuring
14355-405: The early, low-heat smoldering stage of a fire. Smoke from a typical house fire contains hundreds of different chemicals and fumes. As a result, the damage caused by the smoke can often exceed that caused by the actual heat of the fire. In addition to the physical damage caused by the smoke of a fire – which manifests itself in the form of stains – is the often even harder to eliminate problem of
14500-611: The end of the production and phase out of PFOA and PFOS in the US. The general population has been exposed to PFOA through massive dumping of C8 waste into the ocean and near the Ohio River Valley. PFOA has been detected in industrial waste, stain-resistant carpets, carpet cleaning liquids, house dust , microwave popcorn bags , water, food and PTFE cookware. As a result of a class-action lawsuit and community settlement with DuPont , three epidemiologists conducted studies on
14645-426: The fire itself. Cable fires are of special concern; low smoke zero halogen materials are preferable for cable insulation. When smoke comes into contact with the surface of any substance or structure, the chemicals contained in it are transferred to it. The corrosive properties of the chemicals cause the substance or structure to decompose at a rapid rate. Certain materials or structures absorb these chemicals, which
14790-472: The fire occurs is therefore primarily mediated by the smaller particles. Aerosol of particles beyond visible size is an early indicator of materials in a preignition stage of a fire. Burning of hydrogen-rich fuel produces water vapor ; this results in smoke containing droplets of water. In absence of other color sources (nitrogen oxides, particulates...), such smoke is white and cloud -like. Smoke emissions may contain characteristic trace elements. Vanadium
14935-407: The forests of northern Canada in Northern Hemisphere summer) are dominated by smaller aerosols. Human-produced (fossil fuel) pollution is largely responsible for the areas of small aerosols over developed areas such as the eastern United States and Europe, especially in their summer. Satellite measurements of aerosols, called aerosol optical thickness, are based on the fact that the particles change
15080-403: The fuel; hot particles can be present in case of fires during nuclear accidents (e.g. Chernobyl disaster ) or nuclear war . Smoke particulates, like other aerosols, are categorized into three modes based on particle size: Most of the smoke material is primarily in coarse particles. Those undergo rapid dry precipitation , and the smoke damage in more distant areas outside of the room where
15225-562: The gases from which they originate—may have an anthropogenic origin (from biomass and fossil fuel combustion ) as well as a natural biogenic origin. In the presence of ammonia , secondary aerosols often take the form of ammonium salts; i.e. ammonium sulfate and ammonium nitrate (both can be dry or in aqueous solution ); in the absence of ammonia, secondary compounds take an acidic form as sulfuric acid (liquid aerosol droplets) and nitric acid (atmospheric gas). Secondary sulfate and nitrate aerosols are strong light-scatterers . This
15370-418: The general US population in the low and sub- parts per billion range, and levels are higher in chemical plant employees and surrounding subpopulations. PFOA and perfluorooctanesulfonic acid (PFOS) have been estimated to be in every American person's blood stream in the parts per billion range, though those concentrations have decreased by 70% for PFOA and 84% for PFOS between 1999 and 2014, which coincides with
15515-607: The ground by gravity in a matter of hours. The smallest particles (less than 1 micrometer) can stay in the atmosphere for weeks and are mostly removed by precipitation . There are evidence that aerosols can "travel across the ocean". For example, in September 2017 wildfires burning across the western United States and Canada, and the smoke was found to have arrived over the United Kingdom and northern France in three days, as shown by satellite images. Diesel particulate matter
15660-494: The highest CI as the corrosive acids are formed directly with water produced by the combustion, polymers containing halogen only (e.g. polytetrafluoroethylene ) have lower CI as the formation of acid is limited to reactions with airborne humidity, and halogen-free materials (polyolefins, wood ) have the lowest CI. However, some halogen-free materials can also release significant amount of corrosive products. Smoke damage to electronic equipment can be significantly more extensive than
15805-438: The light beams. Corrosivity of smoke produced by materials is characterized by the corrosion index (CI), defined as material loss rate (angstrom/minute) per amount of material gasified products (grams) per volume of air (m). It is measured by exposing strips of metal to flow of combustion products in a test tunnel. Polymers containing halogen and hydrogen ( polyvinyl chloride , polyolefins with halogenated additives, etc.) have
15950-566: The local council. The composition and toxicity of aerosols , including particles, depends on their source and atmospheric chemistry and varies widely. Wind-blown mineral dust tends to be made of mineral oxides and other material blown from the Earth's crust ; this particulate is light-absorbing . Sea salt is considered the second-largest contributor in the global aerosol budget, and consists mainly of sodium chloride originated from sea spray ; other constituents of atmospheric sea salt reflect
16095-408: The lungs. Geometrically angular shapes have more surface area than rounder shapes, which in turn affects the binding capacity of the particle to other, possibly more dangerous substances. The table below lists the colours and shapes of some common atmospheric particulates: Composition of particles can vary greatly depending on their sources and how they are produced. For example, dust emitted from
16240-514: The material of choice as a high-performance substitute for the weaker, higher dispersion and lower-melting-point polyethylene commonly used in low-cost applications. In industrial applications, owing to its low friction, PTFE is used for plain bearings , gears , slide plates , seals, gaskets, bushings, and more applications with sliding action of parts, where it outperforms acetal and nylon . Its extremely high bulk resistivity makes it an ideal material for fabricating long-life electrets ,
16385-411: The material. For example, PTFE is used to prevent ants from climbing out of formicaria . There are surface treatments for PTFE that alter the surface to allow adhesion to other materials. Because of its chemical and thermal properties, PTFE is often used as a gasket material within industries that require resistance to aggressive chemicals such as pharmaceuticals or chemical processing. However, until
16530-521: The military ( smoke screen ), cooking , or smoking ( tobacco , cannabis , etc.). It is used in rituals where incense , sage , or resin is burned to produce a smell for spiritual or magical purposes. It can also be a flavoring agent and preservative. Smoke inhalation is the primary cause of death in victims of indoor fires . The smoke kills by a combination of thermal damage, poisoning and pulmonary irritation caused by carbon monoxide , hydrogen cyanide and other combustion products. Smoke
16675-587: The new fluorinated plastic (analogous to the already known polyethylene ) in 1941, and registered the Teflon trademark in 1945. By 1948, DuPont, which founded Kinetic Chemicals in partnership with General Motors , was producing over 910,000 kilograms (2,000,000 lb) of Teflon-brand polytetrafluoroethylene per year in Parkersburg, West Virginia . An early use was in the Manhattan Project as
16820-408: The number of cloud droplets. This leads to more scattering of shortwave radiation i.e. an increase in the albedo of the cloud, known as the cloud albedo effect, First indirect effect or Twomey effect . Evidence supporting the cloud albedo effect has been observed from the effects of ship exhaust plumes and biomass burning on cloud albedo compared to ambient clouds. The Cloud albedo aerosol effect
16965-424: The otherwise perfectly linear PTFE chain to become branched, reducing its crystallinity. Some PTFE parts are made by cold-moulding, a form of compression molding . Here, fine powdered PTFE is forced into a mould under high pressure (10–100 MPa). After a settling period, lasting from minutes to days, the mould is heated at 360 to 380 °C (680 to 716 °F), allowing the fine particles to fuse ( sinter ) into
17110-422: The particulate to collect on the outer surface of the bag and allowing the now clean air to pass through to either be exhausted into the atmosphere or in some cases recirculated into the facility. Common fabrics include polyester and fiberglass and common fabric coatings include PTFE (commonly known as Teflon). The excess dust buildup is then cleaned from the bags and removed from the collector. Wet scrubbers pass
17255-430: The pollution control facilities and retain the videos for one month for future inspections. Besides removing particulates from the source of pollution, they may also be cleaned in the open air (e.g. smog tower , moss wall , and water truck), while other control measures employ the use of barriers. Particulates have been measured in increasingly sophisticated ways since air pollution was first systematically studied in
17400-445: The polymer chains has such effect too. The naked eye detects particle sizes greater than 7 μm ( micrometres ). Visible particles emitted from a fire are referred to as smoke. Invisible particles are generally referred to as gas or fumes. This is best illustrated when toasting bread in a toaster. As the bread heats up, the products of combustion increase in size. The fumes initially produced are invisible but become visible if
17545-1031: The poor visibility due to the smoke that was in the Worcester Cold Storage Warehouse fire in Worcester, Massachusetts was the reason why the trapped rescue firefighters could not evacuate the building in time. Because of the striking similarity that each floor shared, the dense smoke caused the firefighters to become disoriented. Smoke can contain a wide variety of chemicals, many of them aggressive in nature. Examples are hydrochloric acid and hydrobromic acid , produced from halogen -containing plastics and fire retardants , hydrofluoric acid released by pyrolysis of fluorocarbon fire suppression agents , sulfuric acid from burning of sulfur -containing materials, nitric acid from high-temperature fires where nitrous oxide gets formed, phosphoric acid and antimony compounds from P and Sb based fire retardants, and many others. Such corrosion
17690-500: The population of Parkersburg, WV surrounding the (former DuPont) Chemours Washington Works chemical plant that was exposed to PFOA at levels greater than in the general population. The studies concluded that there was an association between PFOA exposure and six health outcomes: kidney cancer , testicular cancer , ulcerative colitis , thyroid disease , hypercholesterolemia (high cholesterol), and gestational hypertension (pregnancy-induced high blood pressure). Overall, PTFE cookware
17835-511: The possible health risks of construction dust for decades legally require the relevant contractor to adopt effective dust control measures, although inspections, fines and imprisonments are rare in recent years (for example, two prosecutions with a total fines of HKD$ 6000 in Hong Kong in the year 2021). Some of the mandatory dust control measures include load, unload, handle, transfer, store or dispose of cement or dry pulverized fuel ash in
17980-411: The potential of being ignited – either by another open flame in the area, or by its own temperature. This leads to effects like backdraft and flashover . Smoke inhalation is also a danger of smoke that can cause serious injury and death. Many compounds of smoke from fires are highly toxic and/or irritating. The most dangerous is carbon monoxide leading to carbon monoxide poisoning , sometimes with
18125-466: The preindustrial background, is estimated as +0.88 (+0.17, +1.48) W/m ". Volcanoes are a large natural source of aerosol and have been linked to changes in the Earth's climate often with consequences for the human population. Eruptions linked to changes in climate include the 1600 eruption of Huaynaputina which was linked to the Russian famine of 1601–1603 , leading to the deaths of two million, and
18270-465: The presence of sulfur, and SO 2 is converted to sulfate when high humidity and low temperatures are present. This causes reduced visibility and red-orange-yellow colors. Human-produced aerosols such as particle pollution tend to have a smaller radius than aerosol particles of natural origin (such as windblown dust). The false-color maps in the map of distribution of aerosol particles on the right show where there are natural aerosols, human pollution, or
18415-440: The problem some new laws were introduced since 2021. In some towns and cities in New South Wales wood smoke may be responsible for 60% of fine particle air pollution in the winter. There are a few ways to reduce wood smoke, e.g., buying the right wood heater and maintaining it well, choosing the right firewood and burning it the right way. There are also regulations in some countries where people can report smoke pollution to
18560-494: The radiative forcing due to greenhouse gases may be determined to a reasonably high degree of accuracy... the uncertainties relating to aerosol radiative forcings remain large, and rely to a large extent on the estimates from global modeling studies that are difficult to verify at the present time. The direct aerosol effect consists of any direct interaction of radiation with atmospheric aerosols, such as absorption or scattering. It affects both short and longwave radiation to produce
18705-856: The respiratory tract oxidative stress via reactive oxygen species, leading to cellular damage, and systemic effects, such as translocation of ultrafine particles into circulation affects organs beyond the lungs. Exposure to particulate matter is linked to various diseases across body systems, such as respiratory system (asthma, chronic obstructive pulmonary disease (COPD), lung cancer, and rhinosinusitis), cardiovascular system (heart attacks, hypertension, arrhythmias, and atherosclerosis), nervous system (cognitive decline and neurodegenerative diseases), metabolic system (diabetes and metabolic syndrome due to inflammatory pathways). The World Health Organization (WHO) provides guidelines to limit exposure: The site and extent of absorption of inhaled gases and vapors are determined by their solubility in water. Absorption
18850-517: The risk of preterm birth and low birth weight . Sulfate pollution also has a complex relationship with NOx pollution and ozone, reducing the also harmful ground-level ozone , yet capable of damaging the stratospheric ozone layer as well. Once the problem became clear, the efforts to remove this pollution through flue-gas desulfurization measures and other pollution controls were largely successful, reducing their prevalence by 53% and causing healthcare savings valued at $ 50 billion annually in
18995-427: The roots and seeds of wetland plant species, but has not been observed to have an adverse impact on plant health or germination success. Perfluorooctanoic acid (PFOA, or C8) has been used as a surfactant in the emulsion polymerization of PTFE, although several manufacturers have entirely discontinued its use. PFOA persists indefinitely in the environment. PFOA has been detected in the blood of many individuals of
19140-593: The story that GenX was found in the Cape Fear River – the drinking water supply for 500,000 people. The source of the pollution was determined to be the Fayetteville Works site, which had been run by DuPont since its founding in 1971 and then managed by DuPont spinoff, The Chemours Company, since 2015. The water utility confirmed they had no ability to filter these chemicals from the drinking water. The North Carolina Department of Environmental Quality (NC DEQ) records indicate that DuPont started release PFAS into
19285-784: The strongest and most durable materials used in tensile structures . Some notable structures featuring PTFE-tensioned membranes include The O2 Arena in London, Moses Mabhida Stadium in South Africa, Metropolitano Stadium in Spain and the Sydney Football Stadium Roof in Australia. PTFE is often found in musical instrument lubrication products, most commonly valve oil. PTFE is used in some aerosol lubricant sprays, including in micronized and polarized form. It
19430-666: The subject, exposures to secondhand tobacco smoke can activate platelets causing increased clotting and increased risk of thrombus and potentially damage the lining of blood vessels, decrease coronary flow velocity reserves, and reduce heart rate variability, potentially increasing the risk of a heart attack. The chances of these effects occurring increase with increased exposure and time of exposure. The American Cancer Society lists "heart disease, lung infections, increased asthma attacks, middle ear infections, and low birth weight" as ramifications of smoker's emission. Smoke can obscure visibility, impeding occupant exiting from fire areas. In fact,
19575-546: The suppression of drizzle in ship exhaust plume compared to ambient clouds, and inhibited precipitation in biomass burning plumes. This cloud lifetime effect is classified as a climate feedback (rather than a radiative forcing) by the IPCC due to the interdependence between it and the hydrological cycle. However, it has previously been classified as a negative radiative forcing. The Semi-direct effect concerns any radiative effect caused by absorbing atmospheric aerosol such as soot, apart from direct scattering and absorption, which
19720-524: The surface for any pneumatic or power-driven drilling, cutting, polishing or other mechanical breaking operation that causes dust emission, unless there is the operation of an effective dust extraction and filtering device, provide hoarding of not less than 2.4 m in height along the whole length of the site boundary, have hard paving on open area and wash every vehicle that leaves the construction sites. Use of automatic sprinkler equipment, automatic carwash equipment and installation of video surveillance system for
19865-485: The surface to increase the energy and improve adhesion has been reported. PTFE is produced by free-radical polymerization of tetrafluoroethylene . The net equation is Because tetrafluoroethylene can explosively decompose to tetrafluoromethane ( CF 4 {\textstyle {\ce {CF4}}} ) and carbon, a special apparatus is required for the polymerization to prevent hot spots that might initiate this dangerous side reaction. The process
20010-440: The toast is burnt. An ionization chamber type smoke detector is technically a product of combustion detector, not a smoke detector. Ionization chamber type smoke detectors detect particles of combustion that are invisible to the naked eye. This explains why they may frequently false alarm from the fumes emitted from the red-hot heating elements of a toaster, before the presence of visible smoke, yet they may fail to activate in
20155-528: The total mass of aerosols in the atmosphere as estimated in 2010. The remaining 90 percent comes from natural sources such as volcanoes , dust storms , forest and grassland fires, living vegetation and sea spray , emitting particulates such as volcanic ash, desert dust, soot and sea salt. In the United Kingdom domestic combustion is the largest single source of PM 2.5 and PM 10 annually, with domestic wood burning in both closed stoves and open fires responsible for 38% of PM 2.5 in 2019. To tackle
20300-422: The total mass of particles per unit volume of air (particle mass concentration), sometimes it is more useful to measure the total number of particles per unit volume of air ( particle number concentration ). This can be done by using a condensation particle counter (CPC). To measure the atomic composition of particulate samples, techniques such as X-ray spectrometry can be used. Atmospheric aerosols affect
20445-441: The way the atmosphere reflects and absorbs visible and infrared light. As shown in this page , an optical thickness of less than 0.1 (palest yellow) indicates a crystal clear sky with maximum visibility, whereas a value of 1 (reddish-brown) indicates very hazy conditions. In general, the smaller and lighter a particle is, the longer it will stay in the air. Larger particles (greater than 10 micrometers in diameter) tend to settle to
20590-465: Was a Consent Order, signed February 25, 2019 by Cape Fear River Watch, NC DEQ, and Chemours. The order has required Chemours to stop wastewater discharge, air emissions, groundwater discharge, sampling and filtration options to well users, and required sampling that proved there were upwards of 300 distinct PFAS compounds being released from Fayetteville Works. The Teflon trade name is also used for other polymers with similar compositions: These retain
20735-539: Was accidentally discovered in 1938 by Roy J. Plunkett while he was working in Chemours Chambers Works plant in New Jersey for DuPont . A team of Dupont chemists attempted to make a new chlorofluorocarbon refrigerant, called tetrafluoroethylene . The gas in its pressure bottle stopped flowing before the bottle's weight had dropped to the point signaling "empty". John J. Beall (chemist), noticing
20880-416: Was believed to protect the king from evil and disease. More than 300 plant species in 5 continents are used in smoke form for different diseases. As a method of drug administration , smoking is important as it is a simple, inexpensive, but very effective method of extracting particles containing active agents. More importantly, generating smoke reduces the particle size to a microscopic scale thereby increasing
21025-423: Was lethal for parakeets , although that was a higher temperature than the 260 °C (500 °F) required for fumes from pyrolyzed butter to be lethal to the birds. Perfluorooctanoic acid (PFOA), a chemical formerly used in the manufacture of PTFE products such as non-stick coated cookware, can be carcinogenic for people who are exposed to it (see Ecotoxicity ). Concerning levels of PFOA have been found in
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