Smog

Smog is a type of air pollutant. The word "smog" was coined in the early 20th century as a blend of the words smoke and fog to refer to smoky fog, its opacity, and odour. The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid-20th century. This kind of visible air pollution is composed of nitrogen oxides, sulphur oxides, ozone, smoke or dirt particles and also less visible particles such as CFC's. Human-made smog is derived from coal emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions. Modern smog, as found for example in Los Angeles, is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog. In certain other cities, such as Delhi, smog severity is often aggravated by stubble burning in neighboring agricultural areas. The atmospheric pollution levels of Los Angeles, Beijing, Delhi, Lahore, Mexico City, Tehran and other cities are increased by inversion that traps pollution close to the ground. It is usually very highly toxic to humans and can cause severe sickness, shortened life or death.   Smog in New York City as viewed from the World Trade Center in 1988 Etymology Coinage of the term "smog" is generally attributed to Dr. Henry Antoine Des Voeux in his 1905 paper, "Fog and Smoke" for a meeting of the Public Health Congress. The 26 July 1905 edition of the London newspaper Daily Graphic quoted Des Voeux, "He said it required no science to see that there was something produced in great cities which was not found in the country, and that was smoky fog, or what was known as 'smog'." The following day the newspaper stated that "Dr. Des Voeux did a public service in coining a new word for the London fog." However, this is predated by a Los Angeles Times article of January 19, 1893, in which the word is attributed to "a witty English writer." Causes Coal Coal fires, used to heat individual buildings or in a power-producing plant, can emit significant clouds of smoke that contributes to smog. Air pollution from this source has been reported in England since the Middle Ages. London, in particular, was notorious up through the mid-20th century for its coal-caused smogs, which were nicknamed 'pea-soupers.' Air pollution of this type is still a problem in areas that generate significant smoke from burning coal. The emissions from coal combustions are one...

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Exhaust gas

Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline, petrol, biodiesel blends, diesel fuel, fuel oil, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack, or propelling nozzle. It often disperses downwind in a pattern called an exhaust plume. It is a major component of motor vehicle emissions (and from stationary internal combustion engines), which can also include: Crankcase blow-by Evaporation of unused gasoline Motor vehicle emissions contribute to air pollution and are a major ingredient in the creation of smog in some large cities. A 2013 study by MIT indicates that 53,000 early deaths occur per year in the United States alone because of vehicle emissions. According to another study from the same university, traffic fumes alone cause the death of 5,000 people every year just in the United Kingdom. This diesel-powered truck emits an exhaust gas rich in black particulate matter when starting its engine. Composition The largest part of most combustion gas is nitrogen (N2), water vapor (H2O) (except with pure-carbon fuels), and carbon dioxide (CO2) (except for fuels without carbon); these are not toxic or noxious (although carbon dioxide is a greenhouse gas that contributes to global warming). A relatively small part of combustion gas is undesirable, noxious, or toxic substances, such as carbon monoxide (CO) from incomplete combustion, hydrocarbons (properly indicated as CxHy, but typically shown simply as "HC" on emissions-test slips) from unburnt fuel, nitrogen oxides (NOx) from excessive combustion temperatures, and particulate matter (mostly soot). Exhaust gas temperature Exhaust gas temperature (EGT) is important to the functioning of the catalytic converter of an internal combustion engine. It may be measured by an exhaust gas temperature gauge. EGT is also a measure of engine health in gas-turbine engines (see below). Cold engines Steam from tailpipe of cold car During the first two minutes after starting the engine of a car that has not been operated for several hours, the amount of emissions can be very high. This occurs for two main reasons: Rich air-fuel ratio requirement in cold engines: When a cold engine is started, the fuel does not vaporize completely, creating higher emissions of hydrocarbons, nitrogen oxides and carbon monoxide, which diminishes only as the engine reaches operating temperature. The duration of this start-up phase has been reduced by advances in materials and technology, including computer-controlled fuel injection, shorter intake lengths, and pre-heating of fuel and/or inducted air. Inefficient catalytic converter under cold conditions: Catalytic converters are very inefficient until up to their operating temperature. This time has been much reduced by moving the converter closer to the exhaust manifold and even more so placing a small yet quick-to-heat-up converter directly at the...

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Automotive shredder residue

The shredding of automobiles and major household appliances is a process where a hammermill acts as a giant tree chipper by grinding the materials fed into it to fist-size pieces. The shredding of automobiles results in a mixture of ferrous metal, non-ferrous metal (e.g. alloys of copper and aluminium) and shredder waste, called automotive shredder residue or automobile shredder residue (ASR). ASR consists of glass, fiber, rubber, automobile liquids, plastics and dirt. ASR is sometimes differentiated into shredder light fraction and dust. Sometimes these residual materials are called "Car-fluff". ASR often contains hazardous substances such as lead, cadmium, and PCB. Therefore, some countries have classified ASR as hazardous waste and have established legislative controls. a blue 1990s Lincoln Town Car after crushing, with residue visible beneath Recycling It is estimated that every year in EU nations nearly 3 million tonnes of automotive shredder residue (ASR) are generated. While half of the waste which contains rubber, textiles and plastics can be transferred into alternative fuels or recycled, the remaining portion is primarily land-filled. The European Draft directive 2000/53/CE states that by the year 2015, only 5% of the vehicle's weight can be disposed of at landfill sites. Recycling techniques ASR waste contains 30% organic matter and inorganic compounds such as lead, zinc, quartz, calcite, magnetite, anhydrite and hematite. Some of the methods to recycle ASR are: Using as a retarder for ordinary Portland cement by transformation into aggregates after thermal treatment followed by chemical treatment. Conversion of automobile plastic residue into synthetic crude oil. This technology is patented by Agilyx. Recycling thermoplastic materials from residue plastic which can be used in construction and agriculture sector. Use of thermo-chemical processes, such as pyrolysis or gasification. References a b Vermeulen, I. (June 2011). "Automotive shredder residue (ASR): Reviewing its production from end-of-life vehicles (ELVs) and its recycling, energy or chemicals' valorisation". Journal of Hazardous Materials. 190 (1-3): 8–27. doi:10.1016/j.jhazmat.2011.02.088. Chabannet, M.; Péra, J. (April 2004). "Valorization of automotive shredder residue in building materials". Cement and Concrete Research. 34 (4): 557–562. doi:10.1016/j.cemconres.2003.09.004. Fiore, S; Zanetti, M C (April 2012). "Automobile Shredder Residues in Italy: Characterization and valorization opportunities". Waste Management. 32 (8): 1548–1559. doi:10.1016/j.wasman.2012.03.026. Archived from the original on 2015-06-01. "Where does your junk go". Junk Car Medics. Retrieved 30 May 2015. Taylor, Brian (15 May 2012). "Breakthrough Moment". recycling today. Retrieved 30 May 2015.

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Vehicle recycling

Vehicle recycling is the dismantling of vehicles for spare parts. At the end of their useful life, vehicles have value as a source of spare parts and this has created a vehicle dismantling industry. The industry has various names for its business outlets including wrecking yard, auto dismantling yard, car spare parts supplier, and recently, auto or vehicle recycling. Vehicle recycling has always occurred to some degree but in recent years manufacturers have become involved in the process. A car crusher is often used to reduce the size of the scrapped vehicle for transportation to a steel mill. Approximately 12-15 million vehicles reach the end of their use each year in just the United States alone. These automobiles, although out of commission, can still have a purpose by giving back the metal and other recyclable materials that are contained in them. The vehicles are shredded and the metal content is recovered for recycling, while in many areas, the rest is further sorted by machine for recycling of additional materials such as glass and plastics. The remainder, known as automotive shredder residue, is put into a landfill. The shredder residue of the vehicles that is not recovered for metal contains many other recyclable materials including 30% of it as polymers, and 5-10% of it as residual metals. Modern vehicle recycling attempts to be as cost-effective as possible in recycling those residual materials. Currently, 75% of the materials are able to be recycled. As the most recycled consumer product, end-of-life vehicles provide the steel industry with more than 14 million tons of steel. Crushed vehicles ready for transportation to a steel mill. Process Scrap vehicles at Barry Docks The process of recycling a vehicle is extremely complicated as there are many parts to be recycled and many hazardous materials to remove. Briefly, the process begins with incoming vehicles being inventoried for parts. The wheels and tires, battery and catalytic converter are removed. Fluids, such as engine coolant, oil, transmission fluid, air conditioning refrigerant, and gasoline, are drained and removed. Certain high value parts such as electronic modules, alternators, starter motors, infotainment systems - even complete engines or transmissions - may be removed if they are still serviceable and can be profitably sold on; either in "as-is" used condition or to a remanufacturer for restoration. Other hazardous materials such as mercury, and sodium azide (the propellant used in air bags) may also be removed. After all of the parts and products inside are removed, the remaining shell of the vehicle is sometimes subject to further...

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Automotive oil recycling

Automotive oil recycling involves the recycling of used oils and the creation of new products from the recycled oils, and includes the recycling of motor oil and hydraulic oil. Oil recycling also benefits the environment:increased opportunities for consumers to recycle oil lessens the likelihood of used oil being dumped on lands and in waterways. For example, one gallon of motor oil dumped into waterways has the potential to pollute one million gallons of water. Waste oil collection for recycling at the Fairgreen Amenity Site, Portadown Motor oil Oil being drained from an automobile Recycled motor oil can be combusted as fuel, usually in plant boilers, space heaters, or industrial heating applications such as blast furnaces and cement kilns. Recycled motor oil can be distilled into diesel fuel or marine fuel in a process similar to oil re-refining, but without the final hydrotreating process. The lubrication properties of motor oil persist, even in used oil, and it can be recycled indefinitely. Used motor oil re-refining Used oil re-refining is the process of restoring used oil to new oil by removing chemical impurities, heavy metals and dirt. Used Industrial and automotive oil is recycled at re-refineries. The used oil is first tested to determine suitability for re-refining, after which it is dehydrated and the water distillate is treated before being released into the environment. Dehydrating also removes the residual light fuel that can be used to power the refinery, and additionally captures ethylene glycol for re-use in recycled antifreeze. Next, industrial fuel is separated out of the used oil then vacuum distillation removes the lube cut (that is, the fraction suitable for reuse as lubricating oil) leaving a heavy oil that contains the used oil's additives and other by-products such as asphalt extender. The lube cut next undergoes hydro treating, or catalytic hydrogenation to remove residual polymers and other chemical compounds, and saturate carbon chains with hydrogen for greater stability. Final oil separation, or fractionating, separates the oil into three different oil grades: Light viscosity lubricants suitable for general lubricant applications, low viscosity lubricants for automotive and industrial applications, and high viscosity lubricants for heavy-duty applications. The oil that is produced in this step is referred to as re-refined base oil (RRBL). The final step is blending additives into these three grades of oil products to produce final products with the right detergent and anti-friction qualities. Then each product is tested again for quality and purity before being released for sale to the public. References Morton, Peter (November 26, 1991). "Refining sector kicks off oil recycling effort. (in Canada)". The Oil Daily. Retrieved April 17, 2012. (subscription required) a b Alongi , Paul (April 16, 2012). "Greenville County...

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Roadway noise

Roadway noise is the collective sound energy emanating from motor vehicles. It consists chiefly of road surface, tire, engine/transmission, aerodynamic, and braking elements. Noise of rolling tires driving on pavement is found to be the biggest contributor of highway noise which increases with higher vehicle speeds. In developed and developing countries, roadway noise contributes a proportionately large share of the total societal noise pollution. In the U.S., it contributes more to environmental noise exposure than any other noise source. Roadway noise is the most prevalent form of environmental noise. Pictured: São Paulo, Brazil. History Hong Kong roadway generating noise to adjacent land uses. Roadway noise began to be measured in a widespread manner in the 1960s, when computer modeling of this phenomenon was perfected. After passage of the National Environmental Policy Act and Noise Control Act, the demand for detailed analysis soared, and decision makers began to look to acoustical scientists for answers regarding the planning of new roadways and the design of noise mitigation. Partial bans on motor vehicles from urban areas have been shown to have minimal impacts upon reducing sound levels (as would become clear from later modeling studies); for example, the partial ban in Gothenburg, Sweden resulted in minuscule reduction of sound levels. Regulation in the EU and Japan of tire and power-train noise has only sought to reduce noise by approx 3 dB, and will only slowly take effect because a few older noisier vehicles can dominate the soundscape. Causes Speed Traffic operations noise is affected significantly by vehicle speeds, since sound energy roughly doubles for each increment of ten miles an hour in vehicle velocity; an exception to this rule occurs at very low speeds where braking and acceleration noise dominate over aerodynamic noise. Small reductions in vehicle noise occurred in the 1970s as states and provinces enforced unmuffled vehicle ordinances. The vehicle fleet noise has not changed very much over the last three decades; however, if the trend in hybrid vehicle use continues, substantial noise reduction will occur, especially in the regime of traffic flow below 35 miles per hour. Hybrid vehicles are so quiet at low speeds that they create a pedestrian safety issue when reversing or maneuvering when parking etc. (but not when going travelling forward), and so are typically fitted with electric vehicle warning sounds. Vehicles Trucks contribute a disproportionate amount of noise not only because of their large engines, but also the height of the diesel stack and the aerodynamic drag. Significant interior noise is usually present inside moving motor vehicles; in fact, passengers are generally not aware that these levels are high, because experience has led motorists to expect levels commonly exceeding 65 dBA. A sound level...

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