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2010-12-18, 12:30
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رقم المشاركة : 2 | ||||
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اقتباس:
Air Pollution Causes and Effects  History Humans probably first experienced harm from air pollution when they built fires in poorly ventilated caves. Since then we have gone on to pollute more of the earth's surface. Until recently, environmental pollution problems have been local and minor because of the Earth's own ability to absorb and purify minor quantities of pollutants. The industrialization of society, the introduction of motorized vehicles, and the explosion of the population, are factors contributing toward the growing air pollution problem. At this time it is urgent that we find methods to clean up the air. The primary air pollutants found in most urban areas are carbon monoxide, nitrogen oxides, sulfur oxides, hydrocarbons, and particulate matter (both solid and liquid). These pollutants are dispersed throughout the world's atmosphere in concentrations high enough to gradually cause serious health problems. Serious health problems can occur quickly when air pollutants are concentrated, such as when massive injections of sulfur dioxide and suspended particulate matter are emitted by a large volcanic eruption. Air Pollution in the Home You cannot escape air pollution, not even in your own home. "In 1985 the Environmental Protection Agency (EPA) reported that toxic chemicals found in the air of almost every American home are three times more likely to cause some type of cancer than outdoor air pollutants". (Miller 488) The health problems in these buildings are called "sick building syndrome". "An estimated one-fifth to one-third of all U.S. buildings are now considered "sick". (Miller 489) The EPA has found that the air in some office buildings is 100 times more polluted than the air outside. Poor ventilation causes about half of the indoor air pollution problems. The rest come from specific sources such as copying machines, electrical and telephone cables, mold and microbe-harboring air conditioning systems and ducts, cleaning fluids, cigarette smoke, carpet, latex caulk and paint, vinyl molding, linoleum tile, and building materials and furniture that emit air pollutants such as formaldehyde. A major indoor air pollutant is radon-222, a colorless, odorless, tasteless, naturally occurring radioactive gas produced by the radioactive decay of uranium-238. "According to studies by the EPA and the National Research Council, exposure to radon is second only to smoking as a cause of lung cancer". (Miller 489) Radon enters through pores and cracks in concrete when indoor air pressure is less than the pressure of gasses in the soil. Indoor air will be healthier than outdoor air if you use an energy recovery ventilator to provide a consistent supply of fresh filtered air and then seal air leaks in the ****l of your home . Sources of Pollutants   To enlarge an image, click on it. The two main sources of pollutants in urban areas are transportation (predominantly automobiles) and fuel combustion in stationary sources, including residential, commercial, and industrial heating and cooling and coal-burning power plants. Motor vehicles produce high levels of carbon monoxides (CO) and a major source of hydrocarbons (HC) and nitrogen oxides (NOx). Whereas, fuel combustion in stationary sources is the dominant source of sulfur dioxide (SO2). Carbon Dioxide Carbon dioxide (CO2) is one of the major pollutants in the atmosphere. Major sources of CO2 are fossil fuels burning and deforestation. "The concentrations of CO2 in the air around 1860 before the Effects of industrialization were felt, is assumed to have been about 290 parts per million (ppm). In the hundred years and more since then, the concentration has increased by about 30 to 35 ppm that is by 10 percent". (Breuer 67) Industrial countries account for 65% of CO2 emissions with the United States and Soviet Union responsible for 50%. Less developed countries (LDCs), with 80% of the world's people, are responsible for 35% of CO2 emissions but may contribute 50% by 2020. "Carbon dioxide emissions are increasing by 4% a year". (Miller 450) In 1975, 18 thousand million tons of carbon dioxide (*****alent to 5 thousand million tons of carbon) were released into the atmosphere, but the atmosphere showed an increase of only 8 billion tons (*****alent to 2.2 billion tons of carbon". (Breuer 70) The ocean waters contain about sixty times more CO2 than the atmosphere. If the equilibrium is disturbed by externally increasing the concentration of CO2 in the air, then the oceans would absorb more and more CO2. If the oceans can no longer keep pace, then more CO2 will remain into the atmosphere. As water warms, its ability to absorb CO2 is reduced. CO2 is a good transmitter of sunlight, but partially restricts infrared radiation going back from the earth into space. This produces the so-called greenhouse effect that prevents a drastic cooling of the Earth during the night. Increasing the amount of CO2 in the atmosphere reinforces this effect and is expected to result in a warming of the Earth's surface. Currently carbon dioxide is responsible for 57% of the global warming trend. Nitrogen oxides contribute most of the atmospheric contaminants. N0X - nitric oxide (N0) and nitrogen dioxide (N02)
N20 - nitrous oxide
Sulfur and chlorofluorocarbons (CFCs) Sulfur dioxide is produced by combustion of sulfur-containing fuels, such as coal and fuel oils. Also, in the process of producing sulfuric acid and in ****llurgical process involving ores that contain sulfur. Sulfur oxides can injure man, plants and materials. At sufficiently high concentrations, sulfur dioxide irritates the upper respiratory tract of human beings because potential effect of sulfur dioxide is to make breathing more difficult by causing the finer air tubes of the lung to constrict. "Power plants and factories emit 90% to 95% of the sulfur dioxide and 57% of the nitrogen oxides in the United States. Almost 60% of the SO2 emissions are released by tall smoke stakes, enabling the emissions to travel long distances". (Miller 494) As emissions of sulfur dioxide and nitric oxide from stationary sources are transported long distances by winds, they form secondary pollutants such as nitrogen dioxide, nitric acid vapor, and droplets containing solutions of sulfuric acid, sulfate, and nitrate salts. These chemicals descend to the earth's surface in wet form as rain or snow and in dry form as a gases fog, dew, or solid particles. This is known as acid deposition or acid rain. Chlorofluorocarbons (CFCs) CFCs are lowering the average concentration of ozone in the stratosphere. "Since 1978 the use of CFCs in aerosol cans has been banned in the United States, Canada, and most Scandinavian countries. Aerosols are still the largest use, accounting for 25% of global CFC use". (Miller 448) Spray cans, discarded or leaking refrigeration and air conditioning equipment, and the burning plastic foam products release the CFCs into the atmosphere. Depending on the type, CFCs stay in the atmosphere from 22 to 111 years. Chlorofluorocarbons move up to the stratosphere gradually over several decades. Under high energy ultra violet (UV) radiation, they break down and release chlorine atoms, which speed up the breakdown of ozone (O3) into oxygen gas (O2). Chlorofluorocarbons, also known as Freons, are greenhouse gases that contribute to global warming. Photochemical air pollution is commonly referred to as "smog". Smog, a contraction of the words smoke and fog, has been caused throughout recorded history by water condensing on smoke particles, usually from burning coal. With the introduction of petroleum to replace coal economies in countries, photochemical smog has become predominant in many cities, which are located in sunny, warm, and dry climates with many motor vehicles. The worst episodes of photochemical smog tend to occur in summer. Smog  To enlarge the image, click on it. Photochemical smog is also appearing in regions of the tropics and subtropics where savanna grasses are periodically burned. Smog's unpleasant properties result from the irradiation by sunlight of hydrocarbons caused primarily by unburned gasoline emitted by automobiles and other combustion sources. The products of photochemical reactions includes organic particles, ozone, aldehydes, ketones, peroxyacetyl nitrate, organic acids, and other oxidants. Ozone is a gas created by nitrogen dioxide or nitric oxide when exposed to sunlight. Ozone causes eye irritation, impaired lung function, and damage to trees and crops. Another form of smog is called industrial smog. This smog is created by burning coal and heavy oil that contain sulfur impurities in power plants, industrial plants, etc... The smog consists mostly of a mixture of sulfur dioxide and fog. Suspended droplets of sulfuric acid are formed from some of the sulfur dioxide, and a variety of suspended solid particles. This smog is common during the winter in cities such as London, Chicago, Pittsburgh. When these cities burned large amounts of coal and heavy oil without control of the output, large-scale problems were witnessed. In 1952 London, England, 4,000 people died as a result of this form of fog. Today coal and heavy oil are burned only in large boilers and with reasonably good control or tall smokestacks so that industrial smog is less of a problem. However, some countries such as China, Poland, Czechoslovakia, and some other eastern European countries, still burn large quantities of coal without using adequate controls. Pollution Damage to Plants With the destruction and burning of the rain forests more and more CO2 is being released into the atmosphere. Trees play an important role in producing oxygen from carbon dioxide. "A 115 year old Beech tree exposes about 200,000 leaves with a total surface to 1200 square meters. During the course of one sunny day such a tree inhales 9,400 liters of carbon dioxide to produce 12 kilograms of carbohydrate, thus liberating 9,400 liters of oxygen. Through this mechanism about 45,000 liters of air are regenerated which is sufficient for the respiration of 2 to 3 people". (Breuer 1) This process is called photosynthesis which all plants go though but some yield more and some less oxygen. As long as no more wood is burnt than is reproduced by the forests, no change in atmospheric CO2 concentration will result. Pollutants such as sulfur dioxide, nitrogen oxides, ozone and peroxyacl nitrates (PANs), cause direct damage to leaves of crop plants and trees when they enter leaf pores (stomates). Chronic exposure of leaves and needles to air pollutants can also break down the waxy coating that helps prevent excessive water loss and damage from diseases, pests, drought and frost. "In the midwestern United States crop losses of wheat, corn, soybeans, and peanuts from damage by ozone and acid deposition amount to about $5 billion a year". (Miller 498) Reducing Pollution You can help to reduce global air pollution and climate change by driving a car that gets at least 35 miles a gallon, walking, bicycling, and using mass transit when possible. Replace incandescent light bulbs with compact fluorescent bulbs, make your home more energy efficient, and buy only energy efficient appliances. Recycle newspapers, aluminum, and other materials. Plant trees and avoid purchasing products such as Styrofoam that contain CFCs. Support much stricter clean air laws and enforcement of international treaties to reduce ozone depletion and slow global warming. Earth is everybody's home and nobody likes living in a dirty home. Together, we can make the earth a cleaner, healthier and more pleasant place to live. Works Cited:
Miller, G. Tyler, Living in the Environment: an introduction to environmental science. Belmont: Wadsworth, 1990
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2010-12-18, 12:32
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رقم المشاركة : 3 | ||||
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اقتباس:
او هذا بحث آخر Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the physical systems or living organisms they are in.[1] Pollution can take the form of chemical substances, or energy, such as noise, heat, or light energy. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as point source or nonpoint source pollution.
Prehistory But gradually increasing populations and the proliferation of basic industrial processes saw the emergence of a civilization that began to have a much greater collective impact on its surroundings. It was to be expected that the beginnings of environmental awareness would occur in the more developed cultures, particularly in the densest urban centers. The first medium warranting official policy measures in the emerging western world would be the most basic: the air we breathe. The earliest known writings concerned with pollution were Arabic medical treatises written between the 9th and 13th centuries, by physicians such as al-Kindi (Alkindus), Qusta ibn Luqa (Costa ben Luca), Muhammad ibn Zakarīya Rāzi (Rhazes), Ibn Al-Jazzar, al-Tamimi, al-Masihi, Ibn Sina (Avicenna), Ali ibn Ridwan, Ibn Jumay, Isaac Israeli ben Solomon, Abd-el-latif, Ibn al-Quff, and Ibn al-Nafis. Their works covered a number of subjects related to pollution such as air contamination, water contamination, soil contamination, solid waste mishandling, and environmental assessments of certain localities.[3] King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke had become a problem.[4][5] But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow. Air pollution would continue to be a problem there, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. This same city also recorded one of the earlier extreme cases of water quality problems with the Great Stink on the Thames of 1858, which led to construction of the London sewerage system soon afterward. It was the industrial revolution that gave birth to environmental pollution as we know it today. The emergence of great factories and consumption of immense quantities of coal and other fossil fuels gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881. Other cities followed around the country until early in the 20th century, when the short lived Office of Air Pollution was created under the Department of the Interior. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as another public reminder.[6] Modern awareness Early Soviet poster, before the modern awareness: "The smoke of chimneys is the breath of Soviet Russia" Pollution became a popular issue after WW2, when the aftermath of atomic warfare and testing made evident the perils of radioactive fallout. Then a conventional catastrophic event The Great Smog of 1952 in London killed at least 8000 people. This massive event prompted some of the first major modern environmental legislation, The Clean Air Act of 1956. Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water Act and the National Environmental Policy Act. Bad bouts of local pollution helped increase consciousness. PCB dumping in the Hudson River resulted in a ban by the EPA on consumption of its fish in 1974. Long-term dioxin contamination at Love Canal starting in 1947 became a national news story in 1978 and led to the Superfund legislation of 1980. Legal proceedings in the 1990s helped bring to light Chromium-6 releases in California--the champions of whose victims became famous. The pollution of industrial land gave rise to the name brownfield, a term now common in city planning. DDT was banned in most of the developed world after the publication of Rachel Carson's Silent Spring. The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. Lake Karachay, named by the Worldwatch Institute as the "most polluted spot" on earth, served as a disposal site for the Soviet Union thoroughout the 1950s and 1960s. Second place may go to the to the area of Chelyabinsk U.S.S.R. (see reference below) as the "Most polluted place on the planet". Nuclear weapons continued to be tested in the Cold War, sometimes near inhabited areas, especially in the earlier stages of their development. The toll on the worst-affected populations and the growth since then in understanding about the critical threat to human health posed by radioactivity has also been a prohibitive complication associated with nuclear power. Though extreme care is practiced in that industry, the potential for disaster suggested by incidents such as those at Three Mile Island and Chernobyl pose a lingering specter of public mistrust. One legacy of nuclear testing before most forms were banned has been significantly raised levels of background radiation. International catastrophes such as the wreck of the Amoco Cadiz oil tanker off the coast of Brittany in 1978 and the Bhopal disaster in 1984 have demonstrated the universality of such events and the scale on which efforts to address them needed to engage. The borderless nature of atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level with the issue of global warming. Most recently the term persistent organic pollutant (POP) has come to describe a group of chemicals such as PBDEs and PFCs among others. Though their effects remain somewhat less well understood owing to a lack of experimental data, they have been detected in various ecological habitats far removed from industrial activity such as the Arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of widespread use. Growing evidence of local and global pollution and an increasingly informed public over time have given rise to environmentalism and the environmental movement, which generally seek to limit human impact on the environment. Pollution control Humankind has had some effect upon the environment since the Paleolithic era during which the ability to generate fire was acquired. In the Iron Age, the use of tooling led to the practice of ****l grinding on a small scale and resulted in minor accumulations of discarded material probably easily dispersed without too much impact. Human wastes would have polluted rivers or water sources to some degree. However, these effects could be expected predominantly to be dwarfed by the natural world. Ancient cultures The first advanced civilizations of Mesopotamia, Egypt, India, China, Persia, Greece and Rome increased the use of water for their manufacture of goods, increasingly forged ****l and created fires of wood and peat for more elaborate purposes (for example, bathing, heating). The forging of ****ls appears to be a key turning point in the creation of significant air pollution levels. Core samples of glaciers in Greenland indicate increases in air pollution associated with Greek, Roman and Chinese ****l production[2]. Still, at this time the scale of higher activity probably did not disrupt ecosystems. Middle Ages The European Dark Ages during the early Middle Ages probably saw a reprieve in wide spread pollution, in that industrial activity fell, and population levels did not grow rapidly. Toward the end of the Middle Ages populations grew and concentrated more within cities, creating pockets of readily evident contamination. In certain places air pollution levels were recognizable as health issues, and water pollution in population centers was a serious medium for disease transmission from untreated human waste. Since travel and widespread information were less common, there did not exist a more general context than that of local consequences in which to consider pollution. Foul air would have been considered a nuissance and wood, or eventually, coal burning produced smoke, which in sufficient concentrations could be a health hazard in proximity to living quarters. Septic contamination or poisoning of a clean drinking water source was very easily fatal to those who depended on it, especially if such a resource was rare. Superstitions predominated and the extent of such concerns would probably have been little more than a sense of moderation and an avoidance of obvious extremes. Official acknowledgement But gradually increasing populations and the proliferation of basic industrial processes saw the emergence of a civilization that began to have a much greater collective impact on its surroundings. It was to be expected that the beginnings of environmental awareness would occur in the more developed cultures, particularly in the densest urban centers. The first medium warranting official policy measures in the emerging western world would be the most basic: the air we breathe. The earliest known writings concerned with pollution were Arabic medical treatises written between the 9th and 13th centuries, by physicians such as al-Kindi (Alkindus), Qusta ibn Luqa (Costa ben Luca), Muhammad ibn Zakarīya Rāzi (Rhazes), Ibn Al-Jazzar, al-Tamimi, al-Masihi, Ibn Sina (Avicenna), Ali ibn Ridwan, Ibn Jumay, Isaac Israeli ben Solomon, Abd-el-latif, Ibn al-Quff, and Ibn al-Nafis. Their works covered a number of subjects related to pollution such as air contamination, water contamination, soil contamination, solid waste mishandling, and environmental assessments of certain localities.[3] King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke had become a problem.[4][5] But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow. Air pollution would continue to be a problem there, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. This same city also recorded one of the earlier extreme cases of water quality problems with the Great Stink on the Thames of 1858, which led to construction of the London sewerage system soon afterward. It was the industrial revolution that gave birth to environmental pollution as we know it today. The emergence of great factories and consumption of immense quantities of coal and other fossil fuels gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881. Other cities followed around the country until early in the 20th century, when the short lived Office of Air Pollution was created under the Department of the Interior. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as another public reminder.[6] Modern awareness Early Soviet poster, before the modern awareness: "The smoke of chimneys is the breath of Soviet Russia" Pollution became a popular issue after WW2, when the aftermath of atomic warfare and testing made evident the perils of radioactive fallout. Then a conventional catastrophic event The Great Smog of 1952 in London killed at least 8000 people. This massive event prompted some of the first major modern environmental legislation, The Clean Air Act of 1956. Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water Act and the National Environmental Policy Act. Bad bouts of local pollution helped increase consciousness. PCB dumping in the Hudson River resulted in a ban by the EPA on consumption of its fish in 1974. Long-term dioxin contamination at Love Canal starting in 1947 became a national news story in 1978 and led to the Superfund legislation of 1980. Legal proceedings in the 1990s helped bring to light Chromium-6 releases in California--the champions of whose victims became famous. The pollution of industrial land gave rise to the name brownfield, a term now common in city planning. DDT was banned in most of the developed world after the publication of Rachel Carson's Silent Spring. The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. Lake Karachay, named by the Worldwatch Institute as the "most polluted spot" on earth, served as a disposal site for the Soviet Union thoroughout the 1950s and 1960s. Second place may go to the to the area of Chelyabinsk U.S.S.R. (see reference below) as the "Most polluted place on the planet". Nuclear weapons continued to be tested in the Cold War, sometimes near inhabited areas, especially in the earlier stages of their development. The toll on the worst-affected populations and the growth since then in understanding about the critical threat to human health posed by radioactivity has also been a prohibitive complication associated with nuclear power. Though extreme care is practiced in that industry, the potential for disaster suggested by incidents such as those at Three Mile Island and Chernobyl pose a lingering specter of public mistrust. One legacy of nuclear testing before most forms were banned has been significantly raised levels of background radiation. International catastrophes such as the wreck of the Amoco Cadiz oil tanker off the coast of Brittany in 1978 and the Bhopal disaster in 1984 have demonstrated the universality of such events and the scale on which efforts to address them needed to engage. The borderless nature of atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level with the issue of global warming. Most recently the term persistent organic pollutant (POP) has come to describe a group of chemicals such as PBDEs and PFCs among others. Though their effects remain somewhat less well understood owing to a lack of experimental data, they have been detected in various ecological habitats far removed from industrial activity such as the Arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of widespread use. Growing evidence of local and global pollution and an increasingly informed public over time have given rise to environmentalism and the environmental movement, which generally seek to limit human impact on the environment. Pollution control Pollution control is a term used in environmental management. It means the control of emissions and effluents into air, water or soil. Without pollution control, the waste products from consumption, heating, agriculture, mining, manufacturing, transportation and other human activities, whether they accumulate or disperse, will degrade the environment. In the hierarchy of controls, pollution prevention and waste minimization are more desirable than pollution control. Pollution control devices Dust collection systems Cyclones Electrostatic precipitators Baghouses Scrubbers Baffle spray scrubber Cyclonic spray scrubber Ejector venturi scrubber Mechanically aided scrubber Spray tower Wet scrubber Sewage treatment and Wastewater treatment API oil-water separators[7][8] Sedimentation (water treatment) Dissolved air flotation (DAF) Activated sludge biotreaters Biofilters Powdered activated carbon treatment Vapor recovery systems Major forms of pollution and major polluted areas The major forms of pollution are listed below along with the particular pollutants relevant to each of them: Air pollution, the release of chemicals and particulates into the atmosphere. Common gaseous air pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fine dust is characterized by their micron size PM10 to PM2.5. Water pollution, by the release of waste products and contaminants into surface runoff into river drainage systems, leaching into groundwater, liquid spills, wastewater discharges, eutrophication and littering. Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy ****ls, MTBE[9], herbicides, pesticides and chlorinated hydrocarbons. Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment. (See alpha emitters and actinides in the environment.) Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar. Light pollution, includes light trespass, over-illumination and astronomical interference. Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid waste. Thermal pollution, is a temperature change in natural water bodies caused by human influence, such as use of water as coolant in a power plant. The Blacksmith Institute issues annually a list of the world's worst polluted places. In the 2007 issues the ten top nominees are located in Azerbaijan, China, India, Peru, Russia, Ukraine and Zambia. Sources and causes Air pollution comes from both natural and manmade sources. Though globally manmade pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation.[10] Motor vehicle emissions are one of the leading causes of air pollution.[11][12][13] China, United States, Russia, Mexico, and Japan are the world leaders in air pollution emissions. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries,[8] petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, ****ls production factories, plastics factories, and other heavy industry. Agricultural air pollution comes from contemporary practices which include clear felling and burning of natural vegetation as well as spraying of pesticides and herbicides[14] Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy ****ls (such as chromium, cadmium--found in rechargeable batteries, and lead--found in lead paint, aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. In 2001 a series of press reports culminating in a book called Fateful Harvest unveiled a widespread practice of recycling industrial byproducts into fertilizer, resulting in the contamination of the soil with various ****ls. Ordinary municipal landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of polychlorinated dibenzodioxins, commonly called dioxins for simplicity, such as TCDD.[15] Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur. In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted noise worldwide. Effects Human health Adverse air quality can kill many organisms including humans. Ozone pollution can cause respiratory disease, cardiovascular disease, throat inflammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries. Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress, and sleep disturbance. Mercury has been linked to developmental deficits in children and neurologic symptoms. Lead and other heavy ****ls have been shown to cause neurological problems. Chemical and radioactive substances can cause cancer and as well as birth defects. Ecosystems Sulfur dioxide and oxides of nitrogen can cause acid rain which reduces the pH value of soil. Soil can become infertile and unsuitable for plants. This will affect other organisms in the food web. Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis. Invasive species can out compete native species and reduce biodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness. Biomagnification describes a situation where toxins may pass through trophic levels, becoming exponentially more concentrated in the process. Ocean acidification, the ongoing decrease in the pH of the Earth's oceans. Global warming. Regulation and monitoring To protect the environment from the adverse effects of pollution, many nations worldwide have enacted legislation to regulate various types of pollution as well as to mitigate the adverse effects of pollution. Main article: Regulation and monitoring of pollution Philosophical recognition Throughout history from Ancient Greece to Andalusia, Ancient China, central Europe during the Renaissance until today, philosophers ranging from Aristotle, Al-Farabi, Al-Ghazali, Averroes, Buddha, Confucius, Dante, Hegel, Avicenna, Lao Tse, Maimonedes, Montesquieu, Nussbaum, Plato, Socrates and Sun Tzu wrote about the pollution of the body as well as the mind and soul. Perspectives The earliest precursor of pollution generated by life forms would have been a natural function of their existence. The attendant consequences on viability and population levels fell within the sphere of natural selection. These would have included the demise of a population locally or ultimately, species extinction. Processes that were untenable would have resulted in a new balance brought about by changes and adaptations. At the extremes, for any form of life, consideration of pollution is superseded by that of survival. For mankind, the factor of technology is a distinguishing and critical consideration, both as an enabler and an additional source of byproducts. Short of survival, human concerns include the range from quality of life to health hazards. Since science holds experimental demonstration to be definitive, modern treatment of toxicity or environmental harm involves defining a level at which an effect is observable. Common examples of fields where practical measurement is crucial include automobile emissions control, industrial exposure (eg Occupational Safety and Health Administration (OSHA) PELs), toxicology (eg LD50), and medicine (eg medication and radiation doses). "The solution to pollution is dilution", is a dictum which summarizes a traditional approach to pollution management whereby sufficiently diluted pollution is not harmful.[16][17] It is well-suited to some other modern, locally-scoped applications such as laboratory safety procedure and hazardous material release emergency management. But it assumes that the dilutant is in virtually unlimited supply for the application or that resulting dilutions are acceptable in all cases. Such simple treatment for environmental pollution on a wider scale might have had greater merit in earlier centuries when physical survival was often the highest imperative, human population and densities were lower, technologies were simpler and their byproducts more benign. But these are often no longer the case. Furthermore, advances have enabled measurement of concentrations not possible before. The use of statistical methods in evaluating outcomes has given currency to the principle of probable harm in cases where assessment is warranted but resorting to deterministic models is impractical or unfeasible. In addition, consideration of the environment beyond direct impact on human beings has gained prominence. Yet in the absence of a superseding principle, this older approach predominates practices throughout the world. It is the basis by which to gauge concentrations of effluent for legal release, exceeding which penalties are assessed or restrictions applied. The regressive cases are those where a controlled level of release is too high or, if enforceable, is neglected. Migration from pollution dilution to elimination in many cases is confronted by challenging economical and technological barriers. Greenhouse gases and global warming Main article: Global warming Historical and projected CO2 emissions by country. Source: Energy Information Administration.[18][19] Carbon dioxide, while vital for photosynthesis, is sometimes referred to as pollution, because raised levels of the gas in the atmosphere are affecting the Earth's climate. Disruption of the environment can also highlight the connection between areas of pollution that would normally be classified separately, such as those of water and air. Recent studies have investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause slight but critical increases in the acidity of ocean waters, and the possible effects of this on marine ecosystems. See also Environment portal Environmental Science Environmental epidemiology Environmental remediation List of environment topics Timeline of environmental events Air pollution Atmospheric Chemistry Observational Databases - links to freely available data. Category:Air dispersion modeling Emission standard Greenhouse gas Soil contamination Environmental soil science List of waste management companies List of waste management topics List of solid waste treatment technologies Water pollution Cruise ship pollution Marine debris Marine pollution Ship pollution Stormwater Wastewater Wastewater quality indicators Other Contamination control Earth Day Externality Genetic pollution Heat pollution Noise health effects Renewable energy Tragedy of the commons Wise Use References ^ Pollution - Definition from the Merriam-Webster Online Dictionary ^ History of Ancient Copper Smelting Pollution During Roman and Medieval Times Recorded in Greenland Ice, Science no. 272, 1996 ^ L. Gari (2002), "Arabic Treatises on Environmental Pollution up to the End of the Thirteenth Century", Environment and History 8 (4), pp. 475-488. ^ David Urbinato (Summer 1994). "London's Historic "Pea-Soupers"". United States Environmental Protection Agency. Retrieved on 2006-08-02. ^ "Deadly Smog". PBS. 2003-01-17. Retrieved on 2006-08-02. ^ James R. Fleming; Bethany R. Knorr of Colby College. "History of the Clean Air Act". American Meteorological Society. Retrieved on 2006-02-14. ^ American Petroleum Institute (API) (February 1990). Management of Water Discharges: Design and Operations of Oil-Water Separators (1st Edition ed.). American Petroleum Institute. ^ a b Beychok, Milton R. (1967). Aqueous Wastes from Petroleum and Petrochemical Plants (1st Edition ed.). John Wiley & Sons. LCCN 67019834. ^ Concerns about MTBE from U.S. EPA website ^ Declaration of the United Nations Conference on the Human Environment, 1972 ^ Environmental Performance Report 2001 (Transport, Canada website page) ^ State of the Environment, Issue: Air Quality (Australian Government website page) ^ Pollution and Society Marisa Buchanan and Carl Horwitz, University of Michigan ^ Silent Spring, R Carlson, 1962 ^ Beychok, Milton R. (January 1987). "A data base for dioxin and furan emissions from refuse incinerators". Atmospheric Environment 21 (1): 29–36. doi:10.1016/0004-6981(87)90267-8. ^ Gershon Cohen Ph.D.. "The 'Solution' to Pollution Is Still 'Dilution'". Earth Island Institute. Retrieved on 2006-02-14. ^ "What is required". Clean Ocean Foundation. 2001. Retrieved on 2006-02-14. ^ World Carbon Dioxide Emissions (Table 1, Report DOE/EIA-0573, 2004, Energy Information Administration) ^ Carbon dioxide emissions chart (graph on Mongabay website page based on Energy Information Administration's tabulated data) External links Wikimedia Commons has media related to: Pollution Look up Pollution in Wiktionary, the free dictionary. Environmental Defense Fund Environmental Working Group Institute for Energy and Environmental Research OEHHA proposition 65 list OSHA limits for air contaminants National Toxicology Program - from USA National Institutes of Health. Reports and studies on how pollutants affect people. Toxnet - NIH databases and reports on toxicology. Superfund - manages Superfund sites and the pollutants in them (CERCLA). Toxic Release Inventory - tracks how much waste USA companies release into the water and air. Gives permits for releasing specific quantities of these pollutants each year. Map Agency for Toxic Substances and Disease Registry - Top 20 pollutants, how they affect people, what USA industries use them and the products in which they are found The ToxTutor from the National Library of Medicine - a resource to review human toxicology. Pollution Information from, Woods Hole Oceanographic Institution World's Worst Polluted Places 2007, according to the Blacksmith Institute The World's Most Polluted Places at Time.com (a division of Time Magazine) Chelyabinsk: The Most Contaminated Spot on the Planet Documentary Film by Slawomir Grünberg (1996)perantoomână |
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