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Pollution From Wikipedia, the free encyclopedia Jump to: navigation, search

Air pollution from World War II production. Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms.[1] Pollution can take the form of chemical substances, or energy, such as noise, heat, or light. 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. 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.

Ancient cultures The forging of metals appears to be a key turning point in the creation of significant air pollution levels. Core samples of glaciers in Greenland indicate increases in pollution associated with Greek, Roman and Chinese metal production.[2] [edit] Official acknowledgement 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 in England, 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] [edit] 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 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. [edit] Forms of pollution 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 micrometre 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 metals, MTBE,[7] herbicides, pesticides and chlorinated hydrocarbons. •	Littering •	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. [edit] Pollutants Main article: Pollutant A pollutant is a waste material that pollutes air, water or soil. Three factors determine the severity of a pollutant: its chemical nature, the concentration and the persistence. [edit] Sources and causes Air pollution comes from both natural and man made sources. Though globally man made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation.[8] Motor vehicle emissions are one of the leading causes of air pollution.[9][10][11] 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,[12] petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, metals 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[13] About 400 million metric tons of hazardous wastes are generated each year.[14] The United States alone produces about 250 million metric tons.[15] Americans constitute less than 5% of the world's population, but produce roughly 25% of the world’s CO2,[16] and generate approximately 30% of world’s waste.[17][18] In 2007, China has overtaken the United States as the world's biggest producer of CO2.[19] In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists from more than 130 countries, said that humans have been the primary cause of global warming since 1950. Humans have ways to cut greenhouse gas emissions and avoid the consequences of global warming, a major climate report concluded. But in order to change the climate, the transition from fossil fuels like coal and oil needs to occur within decades, according to the final report this year from the UN's Intergovernmental Panel on Climate Change (IPCC).[20] Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy metals (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 metals. 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.[21] 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. [edit] Effects [edit] Human health

Overview of main health effects on humans from some common types of pollution.[22][23][24] 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. An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrhoeal sickness every day.[25] Nearly 500 million Chinese lack access to safe drinking water.[26] 656,000 people die prematurely each year in China because of air pollution. In India, air pollution is believed to cause 527,700 fatalities a year.[27] Studies have estimated that the number of people killed annually in the US could be over 50,000.[28] 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. Older people are majorly exposed to diseases induced by air pollution. Those with heart or lung disorders are under additional risk. Children and infants are also at serious risk. Lead and other heavy metals have been shown to cause neurological problems. Chemical and radioactive substances can cause cancer and as well as birth defects. [edit] Environment Pollution has been found to be present widely in the environment. There are a number of effects of this: •	Sulphur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of soil. •	Nitrogen oxides are removed from the air by rain and fertilise land which can change the species composition of ecosystems. •	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 and leads to the production of tropospheric ozone which damages plants. •	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 situations where toxins (such as heavy metals) may pass through trophic levels, becoming exponentially more concentrated in the process. •	Carbon dioxide emissions cause ocean acidification, the ongoing decrease in the pH of the Earth's oceans as CO2 becomes dissolved. •	The emission of greenhouse gases leads to global warming which affects ecosystems in many ways. [edit] Greenhouse gases and global warming Main article: Global warming

Historical and projected CO2 emissions by country. Source: Energy Information Administration.[32][33] 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 Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere (ozone layer) since the late 1970s, and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period. The latter phenomenon is commonly referred to as the ozone hole. In addition to this well-known stratospheric ozone depletion, there are also tropospheric ozone depletion events, which occur near the surface in polar regions during spring. The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the most important process in both trends is catalytic destruction of ozone by atomic chlorine and bromine.[1] The main source of these halogen atoms in the stratosphere is photodissociation of chlorofluorocarbon (CFC) compounds, commonly called freons, and of bromofluorocarbon compounds known as halons. These compounds are transported into the stratosphere after being emitted at the surface.[2] Both ozone depletion mechanisms strengthened as emissions of CFCs and halons increased. CFCs and other contributory substances are commonly referred to as ozone-depleting substances (ODS). Since the ozone layer prevents most harmful UVB wavelengths (270–315 nm) of ultraviolet light (UV light) from passing through the Earth's atmosphere, observed and projected decreases in ozone have generated worldwide concern leading to adoption of the Montreal Protocol that bans the production of CFCs and halons as well as related ozone depleting chemicals such as carbon tetrachloride and trichloroethane. It is suspected that a variety of biological consequences such as increases in skin cancer, cataracts,[3] damage to plants, and reduction of plankton populations in the ocean's photic zone may result from the increased UV exposure due to ozone depletion. Marine pollution occurs when harmful effects, or potentially harmful effects, can result from the entry into the ocean of chemicals, particles, industrial, agricultural and residential waste, noise, or the spread of invasive organisms. Most sources of marine pollution are land based. The pollution often comes from nonpoint sources such as agricultural runoff and wind blown debris. Many potentially toxic chemicals adhere to tiny particles which are then taken up by plankton and benthos animals, most of which are either deposit or filter feeders. In this way, the toxins are concentrated upward within ocean food chains. Many particles combine chemically in a manner highly depletive of oxygen, causing estuaries to become anoxic. When pesticides are incorporated into the marine ecosystem, they quickly become absorbed into marine food webs. Once in the food webs, these pesticides can cause mutations, as well as diseases, which can be harmful to humans as well as the entire food web. Toxic metals can also be introduced into marine food webs. These can cause a change to tissue matter, biochemistry, behaviour, reproduction, and suppress growth in marine life. Also, many animal feeds have a high fish meal or fish hydrolysate content. In this way, marine toxins can be transferred to land animals, and appear later in meat and dairy products. Ships can pollute waterways and oceans in many ways. Oil spills can have devastating effects. While being toxic to marine life, polycyclic aromatic hydrocarbons (PAHs), the components in crude oil, are very difficult to clean up, and last for years in the sediment and marine environment.[5] Discharge of cargo residues from bulk carriers can pollute ports, waterways and oceans. In many instances vessels intentionally discharge illegal wastes despite foreign and domestic regulation prohibiting such actions. It has been estimated that container ships lose over 10,000 containers at sea each year (usually during storms).[6] Ships also create noise pollution that disturbs natural wildlife, and water from ballast tanks can spread harmful algae and other invasive species.[7] Ballast water taken up at sea and released in port is a major source of unwanted exotic marine life. The invasive freshwater zebra mussels, native to the Black, Caspian and Azov seas, were probably transported to the Great Lakes via ballast water from a transoceanic vessel.[8] Meinesz believes that one of the worst cases of a single invasive species causing harm to an ecosystem can be attributed to a seemingly harmless jellyfish. Mnemiopsis leidyi, a species of comb jellyfish that spread so it now inhabits estuaries in many parts of the world. It was first introduced in 1982, and thought to have been transported to the Black Sea in a ship’s ballast water. The population of the jellyfish shot up exponentially and, by 1988, it was wreaking havoc upon the local fishing industry. “The anchovy catch fell from 204,000 tonnes in 1984 to 200 tons in 1993; sprat from 24,600 tonnes in 1984 to 12,000 tonnes in 1993; horse mackerel from 4,000 tonnes in 1984 to zero in 1993.”[7] Now that the jellyfish have exhausted the zooplankton, including fish larvae, their numbers have fallen dramatically, yet they continue to maintain a stranglehold on the ecosystem. Invasive species can take over once occupied areas, facilitate the spread of new diseases, introduce new genetic material, alter underwater seascapes and jeopardize the ability of native species to obtain food. Invasive species are responsible for about $138 billion annually in lost revenue and management costs in the US alone.[9]

A mute swan builds a nest using plastic garbage. Marine debris is mainly discarded human rubbish which floats on, or is suspended in the ocean. Eighty percent of marine debris is plastic - a component that has been rapidly accumulating since the end of World War II.[35] The mass of plastic in the oceans may be as high as one hundred million metric tons.[36] Discarded plastic bags, six pack rings and other forms of plastic waste which finish up in the ocean present dangers to wildlife and fisheries.[37] Aquatic life can be threatened through entanglement, suffocation, and ingestion.[38][39][40] Fishing nets, usually made of plastic, can be left or lost in the ocean by fishermen. Known as ghost nets, these entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other creatures, restricting movement, causing starvation, laceration and infection, and, in those that need to return to the surface to breathe, suffocation.[41]

Remains of an albatross containing ingested flotsam

Marine debris on Kamilo Beach, Hawaii, washed up from the Great Pacific Garbage Patch Many animals that live on or in the sea consume flotsam by mistake, as it often looks similar to their natural prey.[42] Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection.[43][44] Plastics accumulate because they don't biodegrade in the way many other substances do. They will photodegrade on exposure to the sun, but they do so properly only under dry conditions, and water inhibits this process.[45] In marine environments, photodegraded plastic disintegrates into ever smaller pieces while remaining polymers, even down to the molecular level. When floating plastic particles photodegrade down to zooplankton sizes, jellyfish attempt to consume them, and in this way the plastic enters the ocean food chain. [46] [47] Many of these long-lasting pieces end up in the stomachs of marine birds and animals,[48] including sea turtles, and black-footed albatross.[49] Plastic debris tends to accumulate at the centre of ocean gyres. In particular, the Great Pacific Garbage Patch has a very high level of plastic particulate suspended in the upper water column. In samples taken in 1999, the mass of plastic exceeded that of zooplankton (the dominant animal life in the area) by a factor of six.[35][50] Toxic additives used in the manufacture of plastic materials can leach out into their surroundings when exposed to water. Waterborne hydrophobic pollutants collect and magnify on the surface of plastic debris,[36] thus making plastic far more deadly in the ocean than it would be on land.[35] Hydrophobic contaminants are also known to bioaccumulate in fatty tissues, biomagnifying up the food chain and putting pressure on apex predators. Some plastic additives are known to disrupt the endocrine system when consumed, others can suppress the immune system or decrease reproductive rates.[50] Floating debris can also absorb persistent organic pollutants from seawater, including PCBs, DDT and PAHs.[51] Aside from toxic effects,[52] when ingested some of these are mistaken by the animal brain for estradiol, causing hormone disruption in the affected wildlife Noise pollution See also: Noise pollution, Acoustic ecology, and Marine mammals and sonar Marine life can be susceptible to noise or sound pollution from sources such as passing ships, oil exploration seismic surveys, and naval low-frequency active sonar. Sound travels more rapidly and over larger distances in the sea than in the atmosphere. Marine animals, such as cetaceans, often have weak eyesight, and live in a world largely defined by acoustic information. This applies also to many deeper sea fish, who live in a world of darkness.[66] Between 1950 and 1975, ambient noise in the ocean increased by about ten decibels (that is a ten-fold increase).[67] Noise also makes species communicate louder, which is called the Lombard vocal response.[68] Whale songs are longer when submarine-detectors are on.[69] If creatures don't "speak" loud enough, their voice can be masked by anthropogenic sounds. These unheard voices might be warnings, finding of prey, or preparations of net-bubbling. When one species begins speaking louder, it will mask other specie voices, causing the whole ecosystem to eventually speak louder.[70] According to the oceanographer Sylvia Earle, "Undersea noise pollution is like the death of a thousand cuts. Each sound in itself may not be a matter of critical concern, but taken all together, the noise from shipping, seismic surveys, and military activity is creating a totally different environment than existed even 50 years ago. That high level of noise is bound to have a hard, sweeping impact on life in the sea."[71] Environmental effects

Duck covered in oil as a result of the 2007 San Francisco Bay oil spill.

Oil slicks on Lake Maracaibo.

Oil Slick from the Montara oil spill in the Timor Sea, September, 2009. The oil penetrates and opens up the structure of the plumage of birds, reducing its insulating ability, and so making the birds more vulnerable to temperature fluctuations and much less buoyant in the water. It also impairs birds' flight abilities, making it difficult or impossible to forage and escape from predators. As they attempt to preen, birds typically ingest oil that covers their feathers, causing kidney damage, altered liver function, and digestive tract irritation. This and the limited foraging ability quickly causes dehydration and metabolic imbalances. Hormonal balance alteration including changes in luteinizing protein can also result in some birds exposed to petroleum.[2] Most birds affected by an oil spill die unless there is human intervention.[3][4] Marine mammals exposed to oil spills are affected in similar ways as seabirds. Oil coats the fur of Sea otters and seals, reducing its insulation abilities and leading to body temperature fluctuations and hypothermia. Ingestion of the oil causes dehydration and impaired digestions. Because oil floats on top of water, less light penetrates into the water, limiting the photosynthesis of marine plants and phytoplankton. This, as well as decreasing the fauna populations, affects the food chain in the ecosystem. Colors are much darker	0.0000800	0.0020000	1332	19.500 [edit] Largest oil spills Main article: List of oil spills Oil spills of over 100,000 tonnes or 30 million US gallons, ordered by tonnes[a]

Spill / Tanker	Location	Date	*Tonnes of crude oil	Reference Gulf War oil spill Persian Gulf January 21, 1991	1,360,000–1,500,000	[18][19]

Ixtoc I oil well Gulf of Mexico June 3, 1979–March 23, 1980	454,000–480,000	[20]

Atlantic Empress / Aegean Captain Trinidad and Tobago July 19, 1979	287,000	[21][22]

Fergana Valley Uzbekistan March 2, 1992	285,000	[19]

Nowruz oil field Persian Gulf February 1983	260,000	[23]

ABT Summer 700 nautical miles (1,300 km) off Angola 1991	260,000	[21]

Castillo de Bellver Saldanha Bay, South Africa August 6, 1983	252,000	[21]

Amoco Cadiz Brittany, France March 16, 1978	223,000	[19][21]

Amoco Haven tanker disaster Mediterranean Sea near Genoa, Italy 1991	144,000	[21]

Odyssey 700 nautical miles (1,300 km) off Nova Scotia, Canada 1988	132,000	[21]

Sea Star Gulf of Oman December 19, 1972	115,000	[19][21]

Torrey Canyon Scilly Isles, UK March 18, 1967	80,000–119,000	[19][21]

Irenes Serenade Navarino Bay, Greece 1980	100,000	[21]

Urquiola A Coruña, Spain May 12, 1976	100,000	[21]

Exxon Valdez [b] Gulf of Alaska March 24, 1989	35,000

Wastewater From Wikipedia, the free encyclopedia Jump to: navigation, search For the lake in Northwestern England, see Wastwater. Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations. In the most common usage, it refers to the municipal wastewater that contains a broad spectrum of contaminants resulting from the mixing of wastewaters from different sources. Sewage is correctly the subset of wastewater that is contaminated with feces or urine, but is often used to mean any waste water. "Sewage" includes domestic, municipal, or industrial liquid waste products disposed of, usually via a pipe or sewer or similar structure, sometimes in a cesspool emptier. The physical infrastructure, including pipes, pumps, screens, channels etc. used to convey sewage from its origin to the point of eventual treatment or disposal is termed sewerage. Light pollution From Wikipedia, the free encyclopedia Jump to: navigation, search This article is about light pollution in the visible spectrum. For information on pollution in the radio spectrum, see radio spectrum pollution.

This time exposure photo of New York City at night shows sky glow, one form of light pollution.

Comparison of the view of the night sky from a small rural town (top) and a metropolitan area (bottom). Light pollution vastly reduces the visibility of stars. Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light. The International Dark-Sky Association (IDA) defines light pollution as: Any adverse effect of artificial light including sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste.[1] It obscures the stars in the night sky for city dwellers, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects. Light pollution can be divided into two main types: 1) annoying light that intrudes on an otherwise natural or low-light setting and 2) excessive light (generally indoors) that leads to discomfort and adverse health effects. Since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution. Light pollution is a side effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa like Cairo, but even relatively small amounts of light can be noticed and create problems. Like other forms of pollution (such as air, water, and noise pollution) light pollution causes damage to the environment. Impact on energy usage Energy conservation advocates contend that light pollution must be addressed by changing the habits of society, so that lighting is used more efficiently, with less waste and less creation of unwanted or unneeded illumination. The case against light pollution is strengthened by a range of studies on health effects, suggesting that excess light may induce loss in visual acuity, hypertension, headaches and increased incidence of carcinoma[citation needed]. Several industry groups also recognize light pollution as an important issue. For example, the Institution of Lighting Engineers in the United Kingdom provides its members information about light pollution, the problems it causes, and how to reduce its impact.[2] Since not everyone is irritated by the same lighting sources, it is common for one person's light "pollution" to be light that is desirable for another. One example of this is found in advertising, when an advertiser wishes for particular lights to be bright and visible, even though others find them annoying. Other types of light pollution are more certain. For instance, light that accidentally crosses a property boundary and annoys a neighbor is generally wasted and pollutive light. Disputes are still common when deciding appropriate action, and differences in opinion over what light is considered reasonable, and who should be responsible, mean that negotiation must sometimes take place between parties. Where objective measurement is desired, light levels can be quantified by field measurement or mathematical modeling, with results typically displayed as an isophote map or light contour map. Authorities have also taken a variety of measures for dealing with light pollution, depending on the interests, beliefs and understandings of the society involved. Measures range from doing nothing at all, to implementing strict laws and regulations about how lights may be installed and used. [edit] Types Example of a light pollution source using a broad spectrum metal halide lamp pointing upward. Location: Uniqema Gouda the Netherlands Light pollution is a broad term that refers to multiple problems, all of which are caused by inefficient, unappealing, or (arguably) unnecessary use of artificial light. Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and sky glow. A single offending light source often falls into more than one of these categories. [edit] Light trespass Light trespass occurs when unwanted light enters one's property, for instance, by shining over a neighbor's fence. A common light trespass problem occurs when a strong light enters the window of one's home from the outside, causing problems such as sleep deprivation or the blocking of an evening view. A number of cities in the U.S. have developed standards for outdoor lighting to protect the rights of their citizens against light trespass. To assist them, the International Dark-Sky Association has developed a set of model lighting ordinances.[3] The Dark-Sky Association was started to reduce the light going up into the sky which reduces visibility of stars, see sky glow below. This is any light which is emitted more than 90 degrees above nadir. By limiting light at this 90 degree mark they have also reduced the light output in the 80-90 degree range which creates most of the light trespass issues. U.S. federal agencies may also enforce standards and process complaints within their areas of jurisdiction. For instance, in the case of light trespass by white strobe lighting from communication towers in excess of FAA minimum lighting requirements[4] the FCC maintains an Antenna Structure Registration database[5] information which citizens may use to identify offending structures and provides a mechanism for processing consumer inquiries and complaints.[6] The US Green Building Council (USGBC) has also incorporated into their environmentally friendly building standard known as LEED, a credit for reducing the amount of light trespass and sky glow. Light trespass can be reduced by selecting light fixtures which limit the amount of light emitted more than 80 degrees above the nadir. The IESNA definitions include full cutoff (0%), cutoff (10%), and semi-cutoff (20%). (These definitions also include limits on light emitted above 90 degrees to reduce sky glow.) [edit] Glare Main article: Glare (vision) Glare can be categorized into different types. One such classification is described in a book by Bob Mizon, coordinator for the British Astronomical Association's Campaign for Dark Skies.[11] According to this classification: •	Blinding glare describes effects such as that caused by staring into the Sun. It is completely blinding and leaves temporary or permanent vision deficiencies. •	Disability glare describes effects such as being blinded by oncoming car lights, or light scattering in fog or in the eye, reducing contrast, as well as reflections from print and other dark areas that render them bright, with significant reduction in sight capabilities. •	Discomfort glare does not typically cause a dangerous situation in itself, though it is annoying and irritating at best. It can potentially cause fatigue if experienced over extended periods. According to Mario Motta, president of the Massachusetts Medical Society, ". . . glare from bad lighting is a public-health hazard—especially the older you become. Glare light scattering in the eye causes loss of contrast and leads to unsafe driving conditions, much like the glare on a dirty windshield from low-angle sunlight or the high beams from an oncoming car."[12] In essence bright and/or badly shielded lights around roads may partially blind drivers or pedestrians and contribute to accidents. The blinding effect is caused in large part by reduced contrast due to light scattering in the eye by excessive brightness, or to reflection of light from dark areas in the field of vision, with luminance similar to the background luminance. This kind of glare is a particular instance of disability glare, called veiling glare. (This is not the same as loss of accommodation of night vision which is caused by the direct effect of the light itself on the eye.) [edit] Light clutter Las Vegas displays excessive groupings of colorful lights. This is a classic example of light clutter. Light clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where brightly lit advertising surrounds the roadways. Depending on the motives of the person or organization who installed the lights, their placement and design may even be intended to distract drivers, and can contribute to accidents. Clutter may also present a hazard in the aviation environment if aviation safety lighting must compete for pilot attention with non-relevant lighting.[13] For instance, runway lighting may be confused with an array of suburban commercial lighting and aircraft collision avoidance lights may be confused with ground lights. [edit] Skyglow Main article: Skyglow Mexico City at night, with a brightly illuminated sky. Skyglow refers to the "glow" effect that can be seen over populated areas. It is the combination of all light reflected from what it has illuminated escaping up into the sky and from all of the badly directed light in that area that also escapes into the sky, being scattered (redirected) by the atmosphere back toward the ground. This scattering is very strongly related to the wavelength of the light when the air is very clear (with very little aerosols). Rayleigh scattering dominates in such clear air, making the sky appear blue in the daytime. When there is significant aerosol (typical of most modern polluted conditions), the scattered light has less dependence on wavelength, making a whiter daytime sky. Because of this Rayleigh effect, and because of the eye's increased sensitivity to white or blue-rich light sources when adapted to very low light levels (see Purkinje effect), white or blue-rich light contributes significantly more to sky-glow than an equal amount of yellow light. Sky glow is of particular irritation to astronomers, because it reduces contrast in the night sky to the extent where it may even become impossible to see any but the brightest stars. The Bortle Dark-Sky Scale, originally published in Sky & Telescope magazine,[14] is sometimes used to quantify sky glow and general sky clarity. The Bortle Scale rates the darkness of the sky and the visibility of night sky phenomena such as the gegenschein and the zodiacal band, easily masked by sky glow, on a scale of one to nine, providing a detailed description of each step on the scale. Light is particularly problematic for amateur astronomers, whose ability to observe the night sky from their property is likely to be inhibited by any stray light from nearby. Most major optical astronomical observatories are surrounded by zones of strictly-enforced restrictions on light emissions. "Direct" sky glow can be reduced by selecting lighting fixtures which limit the amount of light emitted more than 90 degrees above the nadir. The IESNA definitions include full cutoff (0%), cutoff (2.5%), and semi-cutoff (5%). "Indirect" skyglow produced by reflections from vertical and horizontal surfaces is harder to manage; the only effective method for preventing it is by minimizing over-illumination. [edit] Measurement and global effects False colors show various intensities of radiation — both direct and indirect — from artificial light sources that reach space (Image credit: P. Cinzano) Measuring the effect of sky glow on a global scale is a complex procedure. The natural atmosphere is not completely dark, even in the absence of terrestrial sources of light and illumination from the Moon. This is caused by two main sources: airglow and scattered light. At high altitudes, primarily above the mesosphere, UV radiation from the sun is so intense that ionization occurs. When these ions collide with electrically neutral particles they recombine and emit photons in the process, causing airglow. The degree of ionization is sufficiently large to allow a constant emission of radiation even during the night when the upper atmosphere is in the Earth's shadow. Apart from emitting light, the sky also scatters incoming light, primarily from distant stars and the Milky Way, but also sunlight that is reflected and backscattered from interplanetary dust particles (the so-called Zodiacal light). The amount of airglow and zodiacal light is quite variable (depending, amongst other things on sunspot activity and the Solar cycle) but given optimal conditions the darkest possible sky has a brightness of about 22 magnitude/square arcsecond. If a full moon is present, the sky brightness increases to 18 magnitude/sq. arcsecond, 40 times brighter than the darkest sky. In densely populated areas a sky brightness of 17 magnitude/sq. arcsecond is not uncommon, or as much as 100 times brighter than is natural. To precisely measure how bright the sky gets, night time satellite imagery of the earth is used as raw input for the number and intensity of light sources. These are put into a physical model[15] of scattering due to air molecules and aerosoles to calculate cumulative sky brightness. Maps that show the enhanced sky brightness have been prepared for the entire world.[16] Inspection of the area surrounding Madrid reveals that the effects of light pollution caused by a single large conglomeration can be felt up to 100 km away from the center. Global effects of light pollution are also made obvious. The entire area consisting of southern England, Netherlands, Belgium, west Germany, and northern France have a sky brightness of at least 2 to 4 times above normal (see above right). The only place in continental Europe where the sky can attain its natural darkness is in northern Scandinavia. In North America the situation is comparable. From the east coast to west Texas up to the Canadian border there is very significant global light pollution. [edit] Consequences [edit] Energy waste Christmas lights in Dublin, California. Lighting is responsible for one-fourth of all energy consumption worldwide,[17] and case studies have shown that several forms of over-illumination constitute energy wastage, including non-beneficial upward direction of night-time lighting. In 2007, Terna, the company responsible for managing electricity flow in Italy, reported a saving of 645.2 million kWh in electricity consumption during the daylight saving period from April to October. It attributes this saving to the delayed need for artificial lighting during the evenings.[18] In Australia, public lighting is the single largest source of local government's greenhouse gas emissions, typically accounting for 30 to 50% of their emissions. There are 1.94 million public lights—one for every 10 Australians—that annually cost A$210 million, use 1,035 GWh of electricity and are responsible for 1.15 million tonnes of CO2 emissions. Current public lighting in Australia, particularly for minor roads and streets, uses large amounts of energy and financial resources, while often failing to provide high quality lighting. There are many ways to improve lighting quality while reducing energy use and greenhouse gas emissions as well as lowering costs.[19] [edit] Effects on animal and human health and psychology Main article: Over-illumination This section needs reorganization to meet Wikipedia's quality standards. There is good information here, but it is poorly organized; editors are encouraged to be bold and make changes to the overall structure to improve this article. (November 2009)

Medical research on the effects of excessive light on the human body suggests that a variety of adverse health effects may be caused by light pollution or excessive light exposure, and some lighting design textbooks[20] use human health as an explicit criterion for proper interior lighting. Health effects of over-illumination or improper spectral composition of light may include: increased headache incidence, worker fatigue, medically defined stress, decrease in sexual function and increase in anxiety.[21][22][23][24] Likewise, animal models have been studied demonstrating unavoidable light to produce adverse effect on mood and anxiety.[25] Common levels of fluorescent lighting in offices are sufficient to elevate blood pressure by about eight points. Specifically within the USA, there is evidence that levels of light in most office environments lead to increased stress as well as increased worker errors.[26][27] Several published studies also suggest a link between exposure to light at night and risk of breast cancer, due to suppression of the normal nocturnal production of melatonin.[28][29] In 1978 Cohen et al. proposed that reduced production of the hormone melatonin might increase the risk of breast cancer and citing "environmental lighting" as a possible causal factor.[30] Researchers at the National Cancer Institute (NCI) and National Institute of Environmental Health Sciences have also concluded a study that suggests that artificial light during the night can be a factor for breast cancer.[31] In 2007, "shift work that involves circadian disruption" was listed as a probable carcinogen by the World Health Organization's International Agency for Research on Cancer. (IARC Press release No. 180).[32] Multiple studies have documented a link between night shift work and the increased incidence of breast cancer.[33][34][35][36] A good review of current knowledge of the health consequences of exposure to artificial light at night and an explanation of the causal mechanisms has been published in the Journal of Pineal Research in 2007.[37] A more recent discussion (2009), written by Professor Steven Lockley, Harvard Medical School, can be found in the CfDS handbook "Blinded by the Light?".[38] Chapter 4, "Human health implications of light pollution" states that "... light intrusion, even if dim, is likely to have measurable effects on sleep disruption and melatonin suppression. Even if these effects are relatively small from night to night, continuous chronic circadian, sleep and hormonal disruption may have longer-term health risks". The New York Academy of Sciences is hosting a 1 day meeting, 19 June 2009 titled Circadian Disruption and Cancer.[39] Moreover remember that 40 Danish women shift workers have this year(2009) been awarded compensation for breast cancer "caused" by shift work made possible by light at night - the most common cause of light pollution. In June, 2009, the American Medical Association developed a policy in support of control of light pollution. News about the decision emphasized glare as a public health hazard leading to unsafe driving conditions. Especially in the elderly, glare produces loss of contrast, obscuring night vision.[12] [edit] Disruption of ecosystems Light pollution poses a serious threat to wildlife, having negative impacts on plant and animal physiology. Light pollution can confuse animal navigation, alter competitive interactions, change predator-prey relations, and cause physiological harm.[40] The rhythm of life is orchestrated by the natural diurnal patterns of light and dark, so disruption to these patterns impacts the ecological dynamics.[41] Studies suggest that light pollution around lakes prevents zooplankton, such as Daphnia, from eating surface algae, helping cause algal blooms that can kill off the lakes' plants and lower water quality.[42] Light pollution may also affect ecosystems in other ways. For example, Lepidopterists and entomologists have documented that nighttime light may interfere with the ability of moths and other nocturnal insects to navigate.[43] Night blooming flowers that depend on moths for pollination may be affected by night lighting, as there is no replacement pollinator that would not be affected by the artificial light. This can lead to species decline of plants that are unable to reproduce, and change an area's longterm ecology. Lights on tall structures can disorient migrating birds. Estimates by the U.S. Fish and Wildlife Service of the number of birds killed after being attracted to tall towers range from 4-5 million per year to an order of magnitude higher.[44] The Fatal Light Awareness Program (FLAP) works with building owners in Toronto, Canada and other cities to reduce mortality of birds by turning out lights during migration periods. Similar disorientation has also been noted for bird species migrating close to offshore production and drilling facilities. Studies carried out by Nederlandse Aardolie Maatschappij b.v. (NAM) and Shell have led to new lighting technologies being developed and trialled in the North Sea. In early 2007 the lights were installed on the Shell production platform L15. The experiment proved a great success since the number of birds circling the platform declined by 50-90% [1] Other well-known casualties of light pollution are sea turtle hatchlings emerging from nests on beaches. It is a common misconception that hatchling sea turtles are attracted to the moon. They are not; rather, they find the ocean by moving away from the dark silhouette of dunes and their vegetation, a behavior with which artificial lights interfere.[45] The breeding activity and reproductive phenology of toads, however, are cued by moonlight.[46] Juvenile seabirds may also be disoriented by lights as they leave their nests and fly out to sea. Amphibians and reptiles are also affected by light pollution. Introduced light sources during normally dark periods can disrupt levels of melatonin production. Melatonin is a hormone that regulates photoperiodic physiology and behaviour. Some species of frogs and salamanders utilize a light-dependent 'compass' to orientate their migratory behaviour to breeding sites. Introduced light can also cause developmental irregularities, such as retinal damage, reduced sperm production, and genetic mutation.[40][47][48][49][50][51] The recent 9th European Dark Sky Symposium, in Armagh, Northern Ireland, September, 2009, had a session on the environmental effects of light at night, LAN. It dealt with bats, turtles, the “hidden” harms of LAN and many other topics. The video can be viewed at this URL – http://www.ustream.tv/recorded/2181927 The environmental effects of LAN are not new. They were remarked on in 1897 in the LA Times, 14 September 1897. The following text is taken from a pdf, which can be obtained from Dr. Travis Longcore, of the Urban Wildlands Trust, California. (Dr. Longcore co-edited, with Dr. Catherine Rich, “Ecological Consequences of Artificial Night Lighting”, Island Press, 2006 - see ref link 49) – “Electricity and English songbirds - An English journal has become alarmed at the relation of electricity to songbirds, which it maintains is closer than that of cats and fodder crops. How many of us, it asks, foresee that electricity may extirpate the songbird? ……With the exception of the finches, all the English songbirds may be said to be insectivorous, and their diet consists chiefly of vast numbers of very small insects which they collect from the grass and herbs before the dew is dry. As the electric light is finding its way for street illumination into the country parts of England, these poor winged atoms are slain by thousands at each light every warm summer evening…… The fear is expressed, that when England is lighted from one end to the other with electricity the song birds will die out from the failure of their food supply.” Sadly song birds are now in decline, along with other insectivores, including the bats discussed in Armagh.

[edit] Effect on astronomy This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2008)

The constellation Orion, imaged at left from dark skies, and at right from within the Provo/Orem, Utah metropolitan area. Skyglow reduces the contrast between stars and galaxies in the sky and the sky itself, making it more difficult to detect fainter objects. This is one factor that has caused newer telescopes to be built in increasingly remote areas. Some astronomers use narrow-band "nebula filters" which only allow specific wavelengths of light commonly seen in nebulae, or broad-band "light pollution filters" which are designed to reduce (but not eliminate) the effects of light pollution by filtering out spectral lines commonly emitted by sodium- and mercury-vapor lamps, thus enhancing contrast and improving the view of dim objects such as galaxies and nebulae. Unfortunately this affects color perception, so these filters cannot be used to visually estimate variable star brightness, and no filter can match the effectiveness of a dark sky for visual or photographic purposes. Due to low surface brightness, the visibility of diffuse sky objects such as nebulae and galaxies is affected by light pollution more than are stars. A simple method for estimating the darkness of a location is to look for the Milky Way. Light trespass can impact observations when stray light enters the tube of the telescope from off-axis, and is reflected from surfaces other than the telescope's mirrors (if any) so that it eventually reaches the eyepiece, causing a glow across the field of view since it has not been focused. The usual measures to reduce this glare, if reducing the light directly (e.g. by changing one's location or having the light turned off) is not an option, include flocking the telescope tube and accessories to reduce reflection, and putting a light shield (also usable as a dew shield) on the telescope to reduce light entering from angles other than those near the target. In one Italian regional lighting code this effect of stray light is defined as "optical pollution"[citation needed], due to the fact that there is a direct path from the light source to the "optic" - the observer's eye or telescope.