PollutionThis is a featured page

Pollution

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 ofchemicalsubstances, orenergy, 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 aspoint sourceornonpoint source pollution.Sometimes the term pollution is extended to include any substance when it occurs at such unnaturally high concentration within a system that it endangers the stability of that system. For example, water is innocuous and essential for life, and yet at very high concentration, it could be considered a pollutant: if a person were to drink an excessive quantity of water, the physical system could be so overburdened that breakdown and even death could result. Another example is the potential of excessive noise to induce imbalance in a person's mental state, resulting in malfunction andpsychosis; this has been used as a weapon in warfare.
History
Prehistory
Humankind has some effect upon the environment since thePaleolithicera during which the ability to generate fire was acquired. In theIron Age, the use of tooling led to the practice ofmetal grindingon 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 ofMesopotamia,Egypt,India,China,Persia,GreeceandRomeincreased the use of water for their manufacture of goods, increasingly forged metal and created fires of wood and peat for more elaborate purposes (for example, bathing, heating). Still, at this time the scale of higher activity did not disrupt ecosystems or greatly alter air or water quality.
Middle Ages
The EuropeanDark Agesduring the earlyMiddle Ageswere a great boon for the environment, 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, andwater pollutionin population centers was a serious medium fordiseasetransmission from untreatedhuman 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 producedsmoke, 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.Superstitionspredominated 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 wereArabic medical treatiseswritten between the 9th and 13th centuries, by physicians such asal-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, andIbn al-Nafis. Their works covered a number of subjects related to pollution such asair contamination,water contamination,soil contamination,solid wastemishandling, andenvironmental assessmentsof certain localities.[2]King Edward IofEnglandbanned the burning ofsea-coalby proclamation inLondonin 1272, after its smoke had become a problem.[3][4]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 theGreat Smog of 1952. This same city also recorded one of the earlier extreme cases of water quality problems with theGreat Stinkon theThamesof 1858, which led to construction of theLondon sewerage systemsoon afterward.It was theindustrial revolutionthat gave birth to environmental pollution as we know it today. The emergence of great factories and consumption of immense quantities ofcoaland otherfossil fuelsgave rise to unprecedentedair pollutionand the large volume of industrialchemicaldischarges added to the growing load of untreated human waste.ChicagoandCincinnatiwere 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 ofLos AngelesandDonora, Pennsylvaniain the late 1940s, serving as another public reminder.[5]
Modern awareness
Early Soviet poster, before the modern awareness: "The smoke of chimneys is the breath of Soviet Russia"
Early Soviet poster, before the modern awareness: "The smoke of chimneys is the breath of Soviet Russia"
Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed theNoise Control Act, theClean Air Act, theClean Water Actand theNational Environmental Policy Act.Bad bouts of local pollution helped increase consciousness.PCBdumping in theHudson Riverresulted in a ban by theEPAon consumption of its fish in 1974. Long-termdioxincontamination atLove Canalstarting in 1947 became a national news story in 1978 and led to theSuperfundlegislation of 1980. Legal proceedings in the 1990s helped bring to lightChromium-6releases inCalifornia--the champions of whose victims became famous. The pollution of industrial land gave rise to the namebrownfield, a term now common incity planning.DDTwas banned in most of the developed world after the publication of Rachel Carson'sSilent Spring.The development of nuclear science introducedradioactive contamination, which can remain lethally radioactive for hundreds of thousands of years.Lake Karachay, named by theWorldwatch Instituteas 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 weaponscontinued to be tested in theCold 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 byradioactivityhas also been a prohibitive complication associated withnuclear power. Though extreme care is practiced in that industry, the potential for disaster suggested by incidents such as those atThree Mile IslandandChernobylpose a lingering specter of public mistrust. One legacy ofnuclear testingbeforemost forms were bannedhas been significantly raised levels ofbackground radiation.International catastrophes such as the wreck of theAmoco Cadizoil tanker off the coast ofBrittanyin 1978 and theBhopal disasterin 1984 have demonstrated the universality of such events and the scale on which efforts to address them needed to engage. The borderless nature of the atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level with the issue of global warming. Most recently the termpersistent organic pollutant(POP) has come to describe a group of chemicals such asPBDEsandPFCsamong 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 toenvironmentalismand theenvironmental movement, which generally seek to limit human impact on the environment.
Pollution control
Pollution control is a term used inenvironmental management. It means the control ofemissionsandeffluentsinto 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 theenvironment. In the hierarchy of controls,pollution preventionandwaste minimizationare more desirable than pollution control.
Pollution control devices

* Dust collection systems
o Cyclones
o Electrostatic precipitators
o Baghouses
* Scrubbers
o Baffle spray scrubber
o Cyclonic spray scrubber
o Ejector venturi scrubber
o Mechanically aided scrubber
o Spray tower
o Wet scrubber
* Sewage treatmentandWastewater treatment
o API oil-water separators[6][7]
o Sedimentation (water treatment)
o Dissolved air flotation(DAF)
o Activated sludge biotreaters
o Biofilters
o 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 includecarbon monoxide,sulfur dioxide,chlorofluorocarbons(CFCs) andnitrogen oxidesproduced byindustryand motor vehicles. Photochemicalozoneandsmogare created as nitrogen oxides andhydrocarbonsreact to sunlight.Particulate matter, characterized by size PM10to PM2.5, is produced from natural sources such as volcanoes or as residual oil fly ash from power plants.Diesel particlesare another class of airborne particulate matter.

* Water pollution, by the release of waste products and contaminants into surfacerunoffinto river drainage systems, leaching intogroundwater, liquid spills,wastewaterdischarges,eutrophicationand littering.
* Soil contaminationoccurs when chemicals are released by spill or underground leakage. Among the most significantsoil contaminantsarehydrocarbons,heavy metals,MTBE[8],herbicides,pesticidesandchlorinated hydrocarbons.
* Radioactive contamination, resulting from 20th century activities inatomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment. (Seealpha emittersandactinides in the environment.)
* Noise pollution, which encompassesroadway noise,aircraft noise,industrial noiseas well as high-intensitysonar.
* Light pollution, includes light trespass,over-illuminationandastronomicalinterference.
* Visual pollution, which can refer to the presence of overheadpower lines, motorwaybillboards, scarredlandforms(as fromstrip mining), open storage of trash ormunicipal solid waste.
* Thermal pollution, is atemperaturechange in natural water bodies caused by human influence, such as use of water as coolant in a power plant.

TheBlacksmith Instituteissues annually a list of the world's worst polluted places. In the 2007 issues the ten top nominees are located inAzerbaijan,China,India,Peru,Russia,UkraineandZambia.
Sources and causes
Motor vehicle emissions are one of the leading causes of air pollution.[9][10][11]China,United States,Russia,Mexico, andJapanare the world leaders in air pollution emissions; however,Canadais the number two country, ranked per capita. Principal stationary pollution sources includechemical plants, coal-firedpower plants,oil refineries,[7]petrochemicalplants,nuclear wastedisposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.),PVCfactories, metals production factories, plastics factories, and other heavy industry.Some of the more commonsoilcontaminants arechlorinated hydrocarbons(CFH),heavy metals(such aschromium,cadmium--found in rechargeablebatteries, andlead--found in leadpaint,aviation fueland still in some countries,gasoline),MTBE,zinc,arsenicandbenzene. In 2001 a series of press reports culminating in a book calledFateful Harvestunveiled a widespread practice of recycling industrial byproducts into fertilizer, resulting in the contamination of the soil with various metals. Ordinary municipallandfillsare 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 ofpolychlorinated dibenzodioxins, commonly calleddioxinsfor simplicity, such asTCDD.[12]Pollution can also be the consequence of a natural disaster. For example,hurricanesoften involve water contamination from sewage, andpetrochemicalspills from rupturedboatsorautomobiles. Larger scale and environmental damage is not uncommon when coastaloil rigsorrefineriesare involved. Some sources of pollution, such asnuclear powerplants oroil tankers, can produce widespread and potentially hazardous releases when accidents occur.In the case ofnoise pollutionthe dominant source class is themotor vehicle, producing about ninety percent of all unwanted noise worldwide.
Effects
Human health
Adverseair qualitycan kill many organisms including humans. Ozone pollution can causerespiratory disease,cardiovascular disease,throatinflammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination ofdrinking waterby untreatedsewageindeveloping countries. Oil spills can causeskinirritations and rashes. Noise pollution induceshearing loss,high blood pressure,stress, andsleep disturbance.Mercuryhas been linked todevelopmental deficitsin children andneurologicsymptoms.Leadand otherheavy metalshave been shown to cause neurological problems. Chemical andradioactivesubstances cancausecancerandas well asbirth defects.
Ecosystems

* Sulfur dioxideand oxides of nitrogen can causeacid rainwhich reduces thepHvalue of soil.
* Soil can become infertile and unsuitable for plants. This will affect otherorganismsin thefood web.
* Smogand haze can reduce the amount of sunlight received by plants to carry outphotosynthesis.
* Invasive speciescan out compete native species and reducebiodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness.
* Biomagnificationdescribes 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 fromAncient GreecetoAndalusia,Ancient China, central Europe during theRenaissanceuntil today, philosophers ranging fromAristotle,Al-Farabi,Al-Ghazali,Averroes,Buddha,Confucius,Dante,Hegel,Avicenna,Lao Tse,Maimonedes,Montesquieu,Nussbaum,Plato,SocratesandSun Tzuwrote about the pollution of thebodyas well as themindandsoul.
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 ofnatural 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 includeautomobile emissions control, industrial exposure (egOccupational Safety and Health Administration(OSHA)PELs),toxicology(egLD50), andmedicine(egmedicationandradiationdoses)."The solution to pollution is dilution", is a dictum which summarizes a traditional approach to pollution management whereby sufficiently diluted pollution is not harmful.[13][14]It is well-suited to some other modern, locally-scoped applications such as laboratory safety procedure andhazardous materialrelease 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.
Controversies
This section does notciteanyreferences or sources.
Please helpimprove this sectionby adding citations toreliable sources.Unverifiablematerial may be challenged and removed.(September 2007)
Industry and concerned citizens have battled for decades over the significance of various forms of pollution. Salient parameters of these disputes are whether:

* a given pollutant affects all people or simply a genetically vulnerable set.
* an effect is only specific to certain species.
* whether the effect is simple, or whether it causes linked secondary and tertiary effects, especially onbiodiversity
* an effect will only be apparent in the future and is presently negligible.
* the threshold for harm is present.
* the pollutant is of direct harm or is a precursor.
* employment or economic prosperity will suffer if the pollutant is abated.

Blooms ofalgaeand the resultanteutrophicationof lakes and coastal ocean is considered pollution when it is caused by nutrients from industrial, agricultural, or residential runoff in eitherpoint sourceornonpoint sourceform (see the article oneutrophicationfor more information).Heavy metals such as lead and mercury have a role in geochemical cycles and they occur naturally. These metals may also be mined and, depending on their processing, may be released disruptively in large concentrations into an environment they had previously been absent from. Just as the effect of anthropogenic release of these metals into the environment may be considered 'polluting', similar environmental impacts could also occur in some areas due to either autochthonous or historically 'natural' geochemical activity.
Greenhouse gases and global warming
Main article:Global warming
Historical and projected CO2 emissions by country. Source: Energy Information Administration.
Historical and projected CO2emissions by country.
Source: Energy Information Administration.[15][16]
Carbon dioxide, while vital forphotosynthesis, 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 criticalincreases in the acidity of ocean waters, and the possible effects of this on marine ecosystems.

Water Pollution

Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater caused by human activities, which can be harmful to organisms and plants which live in these water bodies.
Although natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water, water is typically referred to as polluted when it impaired by anthropogenic contaminants and either does not support a human use (like serving as drinking water) or undergoes a marked shift in its ability to support its constituent biotic communities. Water pollution has many causes and characteristics. The primary sources of water pollution are generally grouped into two categories based on their point of origin. Point-source pollution refers to contaminants that enter a waterway through a discrete "point source". Examples of this category include discharges from a wastewater treatment plant, outfalls from a factory, leaking underground tanks, etc. The second primary category, non-point source pollution, refers to contamination that, as its name suggests, does not originate from a single discrete source. Non-point source pollution is often a cumulative effect of small amounts of contaminants gathered from a large area. Nutrient runoff in storm water from sheet flow over an agricultural field, or metals and hydrocarbons from an area with high impervious surfaces and vehicular traffic are examples of non-point source pollution. The primary focus of legislation and efforts to curb water pollution for the past several decades was first aimed at point sources. As point sources have been effectively regulated, greater attention has come to be placed on non-point source contributions, especially in rapidly urbanizing/suburbanizing or developing areas.
The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical or sensory changes. While many of the chemicals and substances that are regulated may be naturally occurring (iron, manganese, etc) the concentration is often the key in determining what is a natural component of water, and what is a contaminant. Many of the chemical substances are toxic. Pathogens can produce waterborne diseases in either human or animal hosts. Alteration of water's physical chemistry include acidity, electrical conductivity, temperature, and eutrophication. Eutrophication is the fertilization of surface water by nutrients that were previously scarce. Water pollution is a major problem in the global context. It has been suggested that it is the leading worldwide cause of deaths and diseases,[1][2] and that it accounts for the deaths of more than 14,000 people daily.[2]

Most water pollutants are eventually carried by the rivers into the oceans. In some areas of the world the influence can be traced hundred miles from the mouth by studies using hydrology transport models. Advanced computer models such as SWMM or the DSSAM Model have been used in many locations worldwide to examine the fate of pollutants in aquatic systems. Indicator filter feeding species such as copepods have also been used to study pollutant fates in the New York Bight, for example. The highest toxin loads are not directly at the mouth of the Hudson River, but 100 kilometers south, since several days are required for incorporation into planktonic tissue. The Hudson discharge flows south along the coast due to coriolis force. Further south then are areas of oxygen depletion, caused by chemicals using up oxygen and by algae blooms, caused by excess nutrients from algal cell death and decomposition. Fish and shellfish kills have been reported, because toxins climb the foodchain after small fish consume copepods, then large fish eat smaller fish, etc. Each successive step up the food chain causes a stepwise concentration of pollutants such as heavy metals (e.g. mercury) and persistent organic pollutants such as DDT. This is known as biomagnification which is occasionally used interchangeably with bioaccumulation.
The big gyres in the oceans trap floating plastic debris. The North Pacific Gyre for example has collected the so-called "Great Pacific Garbage Patch" that is now estimated at 100 times the size of Texas. Many of these long-lasting pieces wind up in the stomachs of marine birds and animals. This results in obstruction of digestive pathways which leads to reduced appetite or even starvation.
Many chemicals undergo reactive decay or chemically change especially over long periods of time in groundwater reservoirs. A noteworthy class of such chemicals are the chlorinated hydrocarbons such as trichloroethylene (used in industrial metal degreasing and electronics manufacturing) and tetrachloroethylene used in the dry cleaning industry (note latest advances in liquid carbon dioxide in dry cleaning that avoids all use of chemicals). Both of these chemicals, which are carcinogens themselves, undergo partial decomposition reactions, leading to new hazardous chemicals (including dichloroethylene and vinyl chloride).
Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Non-porous aquifers such as clays partially purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, in some cases, chemical reactions and biological activity: however, in some cases, the pollutants merely transform to soil contaminants. Groundwater that moves through cracks and caverns is not filtered and can be transported as easily as surface water. In fact, this can be aggravated by the human tendency to use natural sinkholes as dumps in areas of Karst topography.
There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. Some of these secondary impacts are:
Silt bearing surface runoff from can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants.
Thermal pollution can induce fish kills and invasion by new thermophilic species. This can cause further problems to existing wildlife.

In the UK there are common law rights (civil rights) to protect the passage of water across land unfettered in either quality of quantity. Criminal laws dating back to the 16th century exercised some control over water pollution but it was not until the River (Prevention of pollution )Acts 1951 - 1961 were enacted that any systematic control over water pollution was established. These laws were strengthened and extended in the Control of Pollution Act 1984 which has since been updated and modified by a series of further acts. It is a criminal offense to either pollute a lake, river, groundwater or the sea or to discharge any liquid into such water bodies without proper authority. In England and Wales such permission can only be issued by the Environment Agency and in Scotland by SEPA.
In the USA, concern over water pollution resulted in the enactment of state anti-pollution laws in the latter half of the 19th century, and federal legislation enacted in 1899. The Refuse Act of the federal Rivers and Harbors Act of 1899 prohibits the disposal of any refuse matter from into either the nation's navigable rivers, lakes, streams, and other navigable bodies of water, or any tributary to such waters, unless one has first obtained a permit. The Water Pollution Control Act, passed in 1948, gave authority to the Surgeon General to reduce water pollution.
Growing public awareness and concern for controlling water pollution led to enactment of the Federal Water Pollution Control Act Amendments of 1972. As amended in 1977, this law became commonly known as the Clean Water Act. The Act established the basic mechanisms for regulating contaminant discharge. It established the authority for the United States Environmental Protection Agency to implement wastewater standards for industry. The Clean Water Act also continued requirements to set water quality standards for all contaminants in surface waters. Further amplification of the Act continued including the enactment of the Great Lakes Legacy Act of 2002.[3]

It has been suggested that this article or section be merged into Safe Drinking Water Act. (Discuss)
In 2004, the United States Environmental Protection Agency tested drinking water quality on commercial airline's aircraft and found that 15 percent of tested aircraft tested positive for total coliform bacteria, according to a press release issued on Friday March 28, 2008.[citation needed]

Water pollution

When toxic substances enter lakes, streams, rivers, oceans, and other water bodies, they get dissolved or lie suspended in water or get deposited on the bed. This results in the pollution of water whereby the quality of the water deteriorates, affecting aquatic ecosystems. Pollutants can also seep down and affect the groundwater deposits.

Water pollution has many sources. The most polluting of them are the city sewage and industrial waste discharged into the rivers. The facilities to treat waste water are not adequate in any city in India. Presently, only about 10% of the waste water generated is treated; the rest is discharged as it is into our water bodies. Due to this, pollutants enter groundwater, rivers, and other water bodies. Such water, which ultimately ends up in our households, is often highly contaminated and carries disease-causing microbes. Agricultural run-off, or the water from the fields that drains into rivers, is another major water pollutant as it contains fertilizers and pesticides.

Domestic sewage refers to waste water that is discarded from households. Also referred to as sanitary sewage, such water contains a wide variety of dissolved and suspended impurities.

Biochemical oxygen demand, or BOD
The amount of organic material that can rot in the sewage is measured by the biochemical oxygen demand. BOD is the amount of oxygen required by micro-organisms to decompose the organic substances in sewage. Therefore, the more organic material there is in the sewage, the higher the BOD. It is among the most important parameters for the design and operation of sewage treatment plants. BOD levels of industrial sewage may be many times that of domestic sewage.
Dissolved oxygen is an important factor that determines the quality of water in lakes and rivers. The higher the concentration of dissolved oxygen, the better the water quality. When sewage enters a lake or stream, micro-organisms begin to decompose the organic materials. Oxygen is consumed as micro-organisms use it in their metabolism. This can quickly deplete the available oxygen in the water. When the dissolved oxygen levels drop too low, many aquatic species perish. In fact, if the oxygen level drops to zero, the water will become septic. When organic compounds decompose without oxygen, it gives rise to the undesirable odours usually associated with septic or putrid conditions.

It amounts to a very small fraction of the sewage by weight. But it is large by volume and contains impurities such as organic materials and plant nutrients that tend to rot. The main organic materials are food and vegetable waste, plant nutrient come from chemical soaps, washing powders, etc. Domestic sewage is also very likely to contain disease-causing microbes. Thus, disposal of domestic waste water is a significant technical problem. Sewage generated from the urban areas in India has multiplied manifold since 1947.

Today, many people dump their garbage into streams, lakes, rivers, and seas, thus making water bodies the final resting place of cans, bottles, plastics, and other household products. The various substances that we use for keeping our houses clean add to water pollution as they contain harmful chemicals. In the past, people mostly used soaps made from animal and vegetable fat for all types of washing. But most of today’s cleaning products are synthetic detergents and come from the petrochemical industry. Most detergents and washing powders contain phosphates, which are used to soften the water among other things. These and other chemicals contained in washing powders affect the health of all forms of life in the water.

Agricultural Run off

Eutrophication

When fresh water is artificially supplemented with nutrients, it results in an abnormal increase in the growth of water plants. This is known as eutrophication. The discharge of waste from industries, agriculture, and urban communities into water bodies generally stretches the biological capacities of aquatic systems. Chemical run-off from fields also adds nutrients to water. Excess nutrients cause the water body to become choked with organic substances and organisms. When organic matter exceeds the capacity of the micro-organisms in water that break down and recycle the organic matter, it encourages rapid growth, or blooms, of algae. When they die, the remains of the algae add to the organic wastes already in the water; eventually, the water becomes deficient in oxygen. Anaerobic organisms (those that do not require oxygen to live) then attack the organic wastes, releasing gases such as methane and hydrogen sulphide, which are harmful to the oxygen-requiring (aerobic) forms of life. The result is a foul-smelling, waste-filled body of water. This has already occurred in such places as Lake Erie and the Baltic Sea, and is a growing problem in freshwater lakes all over India. Eutrophication can produce problems such as bad tastes and odours as well as green scum algae. Also the growth of rooted plants increases, which decreases the amount of oxygen in the deepest waters of the lake. It also leads to the death of all forms of life in the water bodies.

The use of land for agriculture and the practices followed in cultivation greatly affect the quality of groundwater. Intensive cultivation of crops causes chemicals from fertilizers (e.g. nitrate) and pesticides to seep into the groundwater, a process commonly known as leaching. Routine applications of fertilizers and pesticides for agriculture and indiscriminate disposal of industrial and domestic wastes are increasingly being recognized as significant sources of water pollution.

The high nitrate content in groundwater is mainly from irrigation run-off from agricultural fields where chemical fertilizers have been used indiscriminately.


Industrial effluents

Waste water from manufacturing or chemical processes in industries contributes to water pollution. Industrial waste water usually contains specific and readily identifiable chemical compounds. During the last fifty years, the number of industries in India has grown rapidly. But water pollution is concentrated within a few subsectors, mainly in the form of toxic wastes and organic pollutants. Out of this a large portion can be traced to the processing of industrial chemicals and to the food products industry. In fact, a number of large- and medium-sized industries in the region covered by the Ganga Action Plan do not have adequate effluent treatment facilities. Most of these defaulting industries are sugar mills, distilleries, leather processing industries, and thermal power stations. Most major industries have treatment facilities for industrial effluents. But this is not the case with small-scale industries, which cannot afford enormous investments in pollution control equipment as their profit margin is very slender.

Effects of water pollution

The effects of water pollution are not only devastating to people but also to animals, fish, and birds. Polluted water is unsuitable for drinking, recreation, agriculture, and industry. It diminishes the aesthetic quality of lakes and rivers. More seriously, contaminated water destroys aquatic life and reduces its reproductive ability. Eventually, it is a hazard to human health. Nobody can escape the effects of water pollution.

The individual and the community can help minimize water pollution. By simple housekeeping and management practices the amount of waste generated can be minimized

INTRODUCTION

Comprising over 70% of the Earth?s surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognize this fact, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our planet to the point where organisms
are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution.


POINT AND NONPOINT SOURCES

According to the American College Dictionary, pollution is defined as: ?to make foul or unclean; dirty.? Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. When it is unfit for its intended use, water is considered polluted. Two types of water pollutants exist; point source and nonpoint source. Point sources of pollution occur when harmful substances are emitted directly into a body of water. The Exxon Valdez oil spill best illustrates a point source water pollution. A nonpoint source delivers pollutants indirectly through environmental changes. An example of this type of water pollution is when fertilizer from a field is carried into a stream by rain, in the form of run-off
which in turn effects aquatic life. The technology exists for point sources of pollution to be monitored and regulated, although political factors may complicate matters. Nonpoint sources are much more difficult to control. Pollution arising from nonpoint
sources accounts for a majority of the contaminants in streams and lakes.


CAUSES OF POLLUTION


Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters.
This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water.
Pollution is also caused when silt and other suspended solids, such as soil, washoff plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respirationbecomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated. Pollution in the form of organic
material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chain.
Polluted River in the United Kingdom
The pollution of rivers and streams with chemical contaminants has become one of the most crutial environmental problems within the 20th century. Waterborne chemical pollution entering rivers and streams cause tramendous amounts of destruction.




Pathogens are another type of pollution that prove very harmful. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and particularly boats that dump sewage. Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness.

ADDITIONAL FORMS OF WATER POLLUTION

Three last forms of water pollution exist in the forms of petroleum, radioactive substances, and heat. Petroleum often pollutes waterbodies in the form of oil, resulting from oil spills. The previously mentioned Exxon Valdez is an example of this type of water pollution. These large-scale accidental discharges of petroleum are an important cause of pollution along shore lines. Besides the supertankers, off-shore drilling operations contribute a large share of pollution. One estimate is that one ton of oil is spilled for every million tons of oil transported. This is equal to about 0.0001 percent. Radioactive substances are produced in the form of waste from nuclear power plants, and from the industrial, medical, and scientific use of radioactive materials. Specific forms of waste are uranium and thorium mining and refining. The last form of water pollution is heat. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms. These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs.
Demonstrators Protest Drilling
Oil pollution is a growing problem, particularly devestating to coastal wildlife. Small quantities of oil spread rapidly across long distances to form deadly oil slicks. In this picture, demonstrators with "oil-covered" plastic animals protest a potential drilling project in Key Largo, Florida. Whether or not accidental spills occur during the project, its impact on the delicate marine ecosystem of the coral reefs could be devastating.

Oil Spill Clean-up
Workers use special nets to clean up a California beach after an oil tanker spill. Tanker spills are an increasing environmental problem because once oil has spilled, it is virtually impossible to completely remove or contain it. Even small amounts spread rapidly across large areas of water. Because oil and water do not mix, the oil floats on the water and then washes up on broad expanses of shoreline. Attempts to chemically treat or sink the oil may further disrupt marine and beach ecosystems.


CLASSIFYING WATER POLLUTION


The major sources of water pollution can be classified as municipal, industrial, and agricultural. Municipal water pollution consists of waste water from homes and commercial establishments. For many years, the main goal of treating municipal
wastewater was simply to reduce its content of suspended solids, oxygen-demanding materials, dissolved inorganic compounds, and harmful bacteria. In recent years, however, more stress has been placed on improving means of disposal of the solid residues from the municipal treatment processes. The basic methods of treating municipal wastewater fall into three stages: primary treatment, including grit removal, screening, grinding, and sedimentation; secondary treatment, which entails oxidation of dissolved organic matter by means of using biologically active sludge, which is then filtered off; and tertiary treatment, in which advanced biological methods of nitrogen removal and chemical and physical methods such as granular filtration and activated carbon absorption are employed. The handling and disposal of solid residues can
account for 25 to 50 percent of the capital and operational costs of a treatment plant. The characteristics of industrial waste waters can differ considerably both within and among industries. The impact of industrial discharges depends not only on their
collective characteristics, such as biochemical oxygen demand and the amount of suspended solids, but also on their content of specific inorganic and organic substances. Three options are available in controlling industrial wastewater. Control can take place at the point of generation in the plant; wastewater can be pretreated for discharge to municipal treatment sources; or wastewater can be treated completely at the plant and either reused or discharged directly into receiving waters.
Wastewater Treatment
Raw sewage includes waste from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused; 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible.



Agriculture, including commercial livestock and poultry farming, is the source of many organic and inorganic pollutants in surface waters and groundwater. These contaminants include both sediment from erosion cropland and compounds of
phosphorus and nitrogen that partly originate in animal wastes and commercial fertilizers. Animal wastes are high in oxygen demanding material, nitrogen and phosphorus, and they often harbor pathogenic organisms. Wastes from commercial
feeders are contained and disposed of on land; their main threat to natural waters, therefore, is from runoff and leaching. Control may involve settling basins for liquids, limited biological treatment in aerobic or anaerobic lagoons, and a variety of other methods.


GROUND WATER

Ninety-five percent of all fresh water on earth is ground water. Ground water is found in natural rock formations. These formations, called aquifers, are a vital natural resource with many uses. Nationally, 53% of the population relies on ground water as a source of drinking water. In rural areas this figure is even higher. Eighty one percent of community water is dependent on ground water. Although the 1992 Section 305(b) State Water Quality Reports indicate that, overall, the Nation?s ground water quality is good to excellent, many local areas have experienced significant ground water contamination.
Some examples are leaking underground storage tanks and municipal landfills.


LEGISLATION


Several forms of legislation have been passed in recent decades to try to control water pollution. In 1970, the Clean Water Act provided 50 billion dollars to cities and states to build wastewater facilities. This has helped control surface water pollution from industrial and municipal sources throughout the United States. When congress passed the Clean Water Act in 1972, states were given primary authority to set their own standards for their water. In addition to these standards, the act required that all state beneficial uses and their criteria must comply with the ?fishable and swimmable? goals of the act. This essentially means that state beneficial uses must be able to support aquatic life and recreational use. Because it is impossible to test water for every type of disease-causing organism, states usually look to identify indicator bacteria. One for a example is a bacteria known as fecal coliforms.(Figure 1 shows the quality of water for each every state in the United States, click on the US link). These indicator bacteria suggest that a certain selection of water may be contaminated with untreated sewage and that other, more dangerous, organisms are present. These legislations are an important part in the fight against water pollution. They are useful in preventing Envioronmental catastrophes. The graph shows reported pollution incidents since 1989-1994. If stronger legislations existed, perhaps these events would never have occurred.


figure 1
GLOBAL WATER POLLUTION

Estimates suggest that nearly 1.5 billion people lack safe drinking water and that at least 5 million deaths per year can be attributed to waterborne diseases. With over 70 percent of the planet covered by oceans, people have long acted as if these very bodies of water could serve as a limitless dumping ground for wastes. Raw sewage, garbage, and oil spills have begun to overwhelm the diluting capabilities of the oceans, and most coastal waters are now polluted. Beaches around the world are closed regularly, often because of high amounts of bacteria from sewage disposal, and marine wildlife is beginning to suffer.

Perhaps the biggest reason for developing a worldwide effort to monitor and restrict global pollution is the fact that most forms of pollution do not respect national boundaries. The first major international conference on environmental issues was held
in Stockholm, Sweden, in 1972 and was sponsored by the United Nations (UN). This meeting, at which the United States took a leading role, was controversial because many developing countries were fearful that a focus on environmental protection was a means for the developed world to keep the undeveloped world in an economically subservient position. The most important outcome of the conference was the creation of the United Nations Environmental Program (UNEP).


UNEP was designed to be ?the environmental conscience of the United Nations,? and, in an attempt to allay fears of the developing world, it became the first UN agency to be headquartered in a developing country, with offices in Nairobi, Kenya. In addition to attempting to achieve scientific consensus about major environmental issues, a major focus for UNEP has been the study of ways to encourage sustainable development increasing standards of living without destroying the environment. At the time of UNEP's creation in 1972, only 11 countries had environmental agencies. Ten years later that number had grown to 106, of which 70 were in developing countries.

WATER QUALITY


Water quality is closely linked to water use and to the state of economic development. In industrialized countries, bacterial contamination of surface water caused serious health problems in major cities throughout the mid 1800?s. By the turn of the century, cities in Europe and North America began building sewer networks to route domestic wastes downstream of water intakes. Development of these sewage networks and waste treatment facilities in urban areas has expanded tremendously in the past two decades. However, the rapid growth of the urban population (especially in Latin America and Asia) has outpaced the ability of governments to expand sewage and water infrastructure. While waterborne diseases have been eliminated in the developed world, outbreaks of cholera and other similar diseases still occur with alarming frequency in the developing countries. Since World War II and the birth of the ?chemical age?, water quality has been heavily impacted worldwide by industrial and agricultural chemicals. Eutrophication of surface waters from human and agricultural wastes and nitrification of groundwater from agricultural practices has greatly affected large parts of the world. Acidification of surface waters by air pollution is a recent phenomenon and threatens aquatic life in many area of the world. In developed countries, these general types of pollution have occurred sequentially with the result that most developed countries have successfully dealt with major surface water pollution. In contrast, however, newly industrialized countries such as China, India, Thailand, Brazil, and Mexico are now facing all these issues simultaneously.


CONCLUSION

Clearly, the problems associated with water pollution have the capabilities to disrupt life on our planet to a great extent. Congress has passed laws to try to combat water pollution thus acknowledging the fact that water pollution is, indeed, a seriousissue. But the government alone cannot solve the entire problem. It is ultimately up to us, to be informed, responsible and involved when it comes to the problems we face with our water. We must become familiar with our local water resources and learn about ways for disposing harmful household wastes so they don?t end up in sewage treatment plants that can?t handle them or landfills not designed to receive hazardous materials. In our yards, we must determine whether additional nutrients are needed before fertilizers are applied, and look for alternatives where fertilizers might run off into surface waters. We have to preserve existing trees and plant new trees and shrubs to help prevent soil erosion and promote infiltration of water into the soil. Around our houses, we must keep litter, pet waste, leaves, and grass clippings out of gutters and storm drains. These are
just a few of the many ways in which we, as humans, have the ability to combat water pollution. As we head into the 21st century, awareness and education will most assuredly continue to be the two most important ways to prevent water pollution. If these measures are not taken and water pollution continues, life on earth will suffer severely.
Global environmental collapse is not inevitable. But the developed world must work with the developing world to ensure that new industrialized economies do not add to the world's environmental problems. Politicians must think of sustainable development rather than economic expansion. Conservation strategies have to become more widely accepted, and people must learn that energy use can be dramatically diminished without sacrificing comfort. In short, with the technology that currently
exists, the years of global environmental mistreatment can begin to be reversed.

Air Pollution

Air pollutionis the human introduction into theatmosphereofchemicals,particulate matter, orbiological materialsthat cause harm or discomfort to humans or other living organisms, or damages the environment.[1]Air pollution causes deaths[2]andrespiratory disease.[3]Air pollution is often identified withmajor stationary sources, but the greatestsource of emissionsis mobile sources, mainlyautomobiles.[4]Gases such ascarbon dioxide, which contribute toglobal warming, have recently gained recognition aspollutantsby climate scientists, while they also recognize that carbon dioxide is essential for plant life throughphotosynthesis.The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planetEarth.Stratosphericozone depletiondue to air pollution has long been recognized as a threat to human health as well as to the Earth'secosystems.
Pollutants
Before flue gas desulfurization was installed, the emissions from this power plant in New Mexico contained excessive amounts of sulfur dioxide.
Beforeflue gas desulfurizationwas installed, the emissions from this power plant inNew Mexicocontained excessive amounts ofsulfur dioxide.
There are many substances in the air which may impair the health of plants and animals (including humans), or reduce visibility. These arise both from natural processes and human activity. Substances not naturally found in the air or at greater concentrations or in different locations from usual are referred to aspollutants.Pollutants can be classified as either primary or secondary. Usually, primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone - one of the many secondary pollutants that make up photochemical smog.Note that some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.Major primary pollutants produced by human activity include:

* Sulfur oxides(SOx) especiallysulfur dioxideare emitted from burning of coal and oil.
* Nitrogen oxides(NOx) especiallynitrogen dioxideare emitted from high temperature combustion. Can be seen as the brown haze dome above orplumedownwind of cities.
* Carbon monoxideis colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.
* Carbon dioxide(CO2), agreenhouse gasemitted from combustion.
* Volatile organic compounds(VOC), such ashydrocarbonfuel vapors andsolvents.
* Particulate matter(PM), measured as smoke and dust. PM10is the fraction of suspended particles 10micrometersin diameter and smaller that will enter the nasal cavity. PM2.5has a maximum particle size of 2.5 µm and will enter the bronchies and lungs.
* Toxicmetals, such aslead,cadmiumandcopper.
* Chlorofluorocarbons(CFCs), harmful to theozone layeremitted from products currently banned from use.
* Ammonia(NH3) emitted from agricultural processes.
* Odors, such as from garbage, sewage, and industrial processes
* Radioactive pollutantsproduced bynuclear explosions, warexplosives, and natural processes such as theradioactive decayofradon.

Secondary pollutants include:

* Particulate matter formed from gaseous primary pollutants and compounds in photochemicalsmog, such as nitrogen dioxide.
* Ground level ozone(O3) formed from NOxand VOCs.
* Peroxyacetyl nitrate(PAN) similarly formed from NOxand VOCs.

Minor air pollutants include:

* A large number of minorhazardous air pollutants. Some of these are regulated in USA under theClean Air Actand in Europe under the Air Framework Directive.
* A variety ofpersistent organic pollutants, which can attach to particulate matter.

Sources
Dust storm approaching Stratford, Texas
Dust storm approachingStratford, Texas
Controlled burning of a field outside of Statesboro, Georgia in preparation for spring planting
Controlled burningof a field outside ofStatesboro, Georgiain preparation for spring planting
Puxi area of Shanghai at sunset. The sun has not actually dropped below the horizon yet, rather it has reached the smog line.
Puxi area ofShanghaiat sunset. The sun has not actually dropped below the horizon yet, rather it has reached thesmogline.
Sources of air pollution refer to the various locations, activities or factors which are responsible for the releasing of pollutants in the atmosphere. These sources can be classified into two major categories which are:Anthropogenic sources(human activity) mostly related to burning different kinds offuel

* "Stationary Sources" as smoke stacks ofpower plants, manufacturing facilities, municipal waste incinerators.
* "Mobile Sources" asmotor vehicles, aircraft etc.
* Marine vessels, such ascontainer shipsorcruise ships, and relatedportair pollution.
* Burningwood,fireplaces,stoves,furnacesandincinerators.
* Oil refining, and industrial activity in general.
* Chemicals, dust andcontrolled burnpractices in agriculture and forestry management, (seeDust Bowl).
* Fumes frompaint,hair spray,varnish,aerosol spraysand other solvents.
* Waste deposition inlandfills, which generatemethane.
* Military, such asnuclear weapons,toxic gases,germ warfareandrocketry.

Natural sources

* Dustfrom natural sources, usually large areas of land with little or no vegetation.
* Methane,emittedby thedigestionof food byanimals, for examplecattle.
* Radongas from radioactive decay within the Earth's crust.
* Smokeandcarbon monoxidefromwildfires.
* Volcanicactivity, which producesulfur,chlorine, and ashparticulates.

Emission factors
Main article:AP 42 Compilation of Air Pollutant Emission Factors
Airpollutantemission factors are representative values that attempt to relate the quantity of a pollutant released to the ambient air with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per megagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages.TheUnited States Environmental Protection Agencyhas published a compilation of air pollutant emission factors for a multitude of industrial sources.[5]TheUnited Kingdom,Australia,Canadaand other countries have published similar compilations, as has theEuropean Environment Agency.[6][7][8][9][10]
Indoor air quality (IAQ)
Main article:Indoor air quality
A lack of ventilation indoors concentrates air pollution where people often spend the majority of their time.Radon(Rn) gas, acarcinogen, is exuded from the Earth in certain locations and trapped inside houses. Building materials includingcarpetingandplywoodemitformaldehyde(H2CO) gas. Paint and solvents give offvolatile organic compounds(VOCs) as they dry.Leadpaint can degenerate intodustand be inhaled. Intentional air pollution is introduced with the use ofair fresheners,incense, and other scented items. Controlledwoodfires instovesandfireplacescan add significant amounts of smoke particulates into the air, inside and out. Indoor pollution fatalities may be caused by usingpesticidesand other chemical sprays indoors without proper ventilation.Carbon monoxide(CO) poisoning and fatalities are often caused by faulty vents and chimneys, or by the burning ofcharcoalindoors. Chronic carbon monoxide poisoning can result even from poorly adjustedpilot lights. Traps are built into all domesticplumbingto keep sewer gas,hydrogen sulfide, out of interiors. Clothing emitstetrachloroethylene, or other dry cleaning fluids, for days afterdry cleaning.Though its use has now been banned in many countries, the extensive use ofasbestosin industrial and domestic environments in the past has left a potentially very dangerous material in many localities.Asbestosisis a chronicinflammatorymedical condition affecting the tissue of thelungs. It occurs after long-term, heavy exposure to asbestos from asbestos-containing materials in structures. Sufferers have severedyspnea(shortness of breath) and are at an increased risk regarding several different types oflung cancer. As clear explanations are not always stressed in non-technical literature, care should be taken to distinguish between several forms of relevant diseases. According to theWorld Health Organisation (WHO), these may defined as;asbestosis,lung cancer, andmesothelioma(generally a very rare form of cancer, when more widespread it is almost always associated with prolonged exposure to asbestos).Biological sources of air pollution are also found indoors, as gases and airborne particulates.Petsproduce dander, people produce dust from minute skin flakes and decomposed hair, dustmitesin bedding, carpeting and furniture produce enzymes and micrometre-sized fecal droppings, inhabitants emitmethane,moldforms in walls and generatesmycotoxinsand spores,air conditioningsystems can incubateLegionnaires' diseaseand mold, andhouseplants, soil and surroundinggardenscan producepollen, dust, and mold. Indoors, the lack of air circulation allows these airborne pollutants to accumulate more than they would otherwise occur in nature.
Health effects
The World Health Organization states that 2.4 million people die each year from causes directly attributable to air pollution, with 1.5 million of these deaths attributable to indoor air pollution.[3]"Epidemiologicalstudies suggest that more than 500,000 Americans die each year fromcardiopulmonarydisease linked to breathingfine particle air pollution. . ."[11]A study by theUniversity of Birminghamhas shown a strong correlation betweenpneumoniarelated deaths and air pollution from motor vehicles.[12]Worldwide more deaths per year are linked to air pollution than to automobile accidents.[citation needed]Published in 2005 suggests that 310,000 Europeans die from air pollution annually.[citation needed]Direct causes of air pollution related deaths include aggravated asthma, bronchitis, emphysema, lung and heart diseases, and respiratory allergies.[citation needed]TheUS EPAestimates that a proposed set of changes indieselengine technology (Tier 2) could result in 12,000 fewerpremature mortalities, 15,000 fewerheart attacks, 6,000 feweremergency roomvisits by children withasthma, and 8,900 fewer respiratory-related hospital admissions each year in the United States.[citation needed]The worst short term civilian pollution crisis inIndiawas the 1984Bhopal Disaster.[13]Leaked industrial vapors from the Union Carbide factory, belonging to Union Carbide, Inc., U.S.A., killed more than 2,000 people outright and injured anywhere from 150,000 to 600,000 others, some 6,000 of whom would later die from their injuries.[citation needed]TheUnited Kingdomsuffered its worst air pollution event when theDecember 4Great Smog of 1952formed overLondon. In six days more than 4,000 died, and 8,000 more died within the following months.[citation needed]An accidental leak ofanthraxspores from abiological warfarelaboratory in the formerUSSRin 1979 nearSverdlovskis believed to have been the cause of hundreds of civilian deaths.[citation needed]The worst single incident of air pollution to occur in theUnited States of Americaoccurred inDonora, Pennsylvaniain late October, 1948, when 20 people died and over 7,000 were injured.[14]The health effects caused by air pollutants may range from subtle biochemical and physiological changes to difficulty in breathing, wheezing, coughing and aggravation of existing respiratory and cardiac conditions. These effects can result in increased medication use, increased doctor or emergency room visits, more hospital admissions and premature death. The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, the individual's health status and genetics.[citation needed]
Effects on cystic fibrosis
Main article:Cystic fibrosis
A study from 1999 to 2000 by theUniversity of Washingtonshowed that patients near and around particulate matter air pollution had an increased risk of pulmonary exacerbations and decrease in lung function.[15]Patients were examined before the study for amounts of specific pollutants likePseudomonas aeruginosaorBurkholderia cenocepaciaas well as their socioeconomic standing. Participants involved in the study were located in the United States in close proximity to anEnvironmental Protection Agency. During the time of the study 117 deaths were associated with air pollution. A trend was noticed that patients living closer or in large metropolitan areas to be close to medical help also had higher level of pollutants found in their system because of more emissions in larger cities. With cystic fibrosis patients already being born with decreased lung function everyday pollutants such as smoke emissions from automobiles, tobacco smoke and improper use of indoor heating devices could add to the dissemination of lung function.[16]
Effects on COPD
Main article:COPD
Chronic obstructive pulmonary disease(COPD) include diseases such aschronic bronchitis,emphysema, and some forms ofasthma.[17]Two researchers Holland and Reid conducted research on 293 male postal workers in London during the time of theGreat Smog of 1952incident and 477 male postal workers in the rural setting. The volume of air that could be exhaled in 1 second (FEV1) was significantly lower in urban employees due to city pollutions such as car fumes and increased amount of cigarette exposure.[18][verification needed]It is believed that much likecystic fibrosis, by living in a more urban environment serious health hazards become more apparent. Studies have shown that in urban areas patients suffermucushypersecretion, lower levels of lung function, and more self diagnosis of chronic bronchitis and emphysema.[19]
The Great Smog of 1952
Main article:Great Smog of 1952
In the matter of four days a combination of dense fog and sooty black coal smoke came over the London area.[20]The fog was so dense residents of London could not see in front of them. The extreme reduction in visibility was accompanied by an increase in criminal activity as well as transportation delays and a virtual shut down of the city. During the 4 day period of the fog 12,000 are believed to have been killed.[21]
Effects on children
Cities around the world with high exposure to air pollutants has the possibility of children living within them to developasthma,pneumoniaand other lower respiratory infections as well as a low initial birth rate. Protective measures to ensure the youths health is being taken in cities such asNew Delhi, Indiawhere buses now use compressed natural gas to help eliminate the “pea-soup” fog.[22]Research by theWorld Health Organizationshows there is the greatest concentration of particulate matter particles in countries with low economic world power and high poverty and population rates. Examples of these countries includeEgypt,Sudan,Mongolia, andIndonesia. TheClean Air Actwas passed in 1970, however in 2002 at least 146 million Americans were living in areas that did not meet at least one of the “criteria pollutants” laid out in the 1997 National Ambient Air Quality Standards.[23]Those pollutants included: ozone, particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. Because children are outdoors more and have higher minute ventilation they are more susceptible to the dangers of air pollution.
Reduction efforts
There are various air pollution control technologies andurban planningstrategies available to reduce air pollution.Efforts to reduce pollution from mobile sources includes primary regulation (many developing countries have permissive regulations),[citation needed]expanding regulation to new sources (such ascruiseand transport ships, farm equipment, and small gas-powered equipment such as lawn trimmers,chainsaws, andsnowmobiles), increased fuel efficiency (such as through the use ofhybrid vehicles), conversion to cleaner fuels (such asbioethanol,biodiesel, or conversion to electric vehicles).
Control devices
The following items are commonly used as pollution control devices by industry or transportation devices. They can either destroycontaminantsor remove them from an exhaust stream before it is emitted into the atmosphere.

* Particulate control
o Mechanical collectors (dust cyclones,multicyclones)
o Electrostatic precipitators
o Baghouses
o Particulate scrubbers

* Scrubbers
o Baffle spray scrubber
o Cyclonic spray scrubber
o Ejector venturi scrubber
o Mechanically aided scrubber
o Spray tower
o Wet scrubber

* NOx control
o Low NOx burners
o Selective catalytic reduction(SCR)
o Selective non-catalytic reduction(SNCR)
o NOx scrubbers
o Exhaust gas recirculation
o Catalytic converter(also for VOC control)

* VOC abatement
o Adsorption systems, such asactivated carbon
o Flares
o Thermal oxidizers
o Catalytic oxidizers
o Biofilters
o Absorption (scrubbing)
o Cryogenic condensers
o Vapor recovery systems

* Acid Gas/SO2control
o Wet scrubbers
o Dry scrubbers
o Flue gas desulfurization

* Mercurycontrol
o Sorbent Injection Technology
o Electro-Catalytic Oxidation(ECO)
o K-Fuel

* Dioxinandfurancontrol

* Miscellaneous associated equipment
o Source capturing systems
o Continuous emissions monitoring systems(CEMS)

Legal regulations
Globe icon
The examples and perspective in this article or section may not represent aworldwide viewof the subject.
Pleaseimprove this articleor discuss the issue on thetalk page.
Smog in Cairo
Smog in Cairo
In general, there are two types of air quality standards. The first class of standards (such as the U.S.National Ambient Air Quality Standards) set maximum atmospheric concentrations for specific pollutants. Environmental agencies enact regulations which are intended to result in attainment of these target levels. The second class (such as the North AmericanAir Quality Index) take the form of a scale with various thresholds, which is used to communicate to the public the relative risk of outdoor activity. The scale may or may not distinguish between different pollutants.
Canada
In Canada, air quality is typically evaluated against standards set by theCanadian Council of Ministers of the Environment(CCME), an inter-governmental body of federal, provincial and territorial Ministers responsible for the environment. The CCME has setCanada Wide Standards(CWS).[24][25]These are:

* CWS forPM2.5= 30 µg/m3 (24 hour averaging time, by year 2010, based on 98th percentile ambient measurement annually, averaged over 3 consecutive years).

* CWS forozone= 65 ppb (8-hour averaging time, by year 2010, achievement is based on the 4th highest measurement annually, averaged over 3 consecutive years.

Note that there is no consequence in Canada to not achieving these standards. In addition, these only apply to jurisdictions with populations greater than 100,000. Further, provinces and territories may set more stringent standards than those set by the CCME.
European Union
It has been suggested that this section besplitinto a new article entitledAir pollution in the European Union. (Discuss)
A report from theEuropean Environment Agencyshows thatroad transportremains Europe’s single largest air polluter[26].National Emission Ceilings (NEC) for certain atmospheric pollutants are regulated by Directive 2001/81/EC (NECD).[27]As part of the preparatory work associated with the revision of the NECD, theEuropean Commissionis assisted by the NECPI working group (National Emission Ceilings – Policy Instruments).[28]Directive 2008/50/ECof the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe (the new Air Quality Directive) has entried into force 2008-06-11[29].Individual citizens can force their local councils to tackle air pollution, following an important ruling in July 2008 from theEuropean Court of Justice(ECJ). The EU’s court was asked to judge the case of a resident of Munich,Dieter Janecek, who said that under the 1996 EU Air Quality Directive (Council Directive 96/62/ECof 27 September 1996 on ambient air quality assessment and management[30]) theMunichauthorities were obliged to take action to stop pollution exceeding specified targets. Janecek then took his case to the ECJ, whose judges said European citizens are entitled to demand air quality action plans from local authorities in situations where there is a risk that EU limits will be overshot.[31].United KingdomAir quality targets set by theUK's Department for Environment, Food and Rural Affairs (DEFRA)are mostly aimed at local government representatives responsible for the management of air quality in cities, where air quality management is the most urgent. The UK has established an air quality network where levels of the key air pollutants[32]are published by monitoring centers.[33]Air quality inOxford,BathandLondon[34]is particularly poor. One controversial study[35]performed by theCalor Gas companyand published inthe Guardian newspapercompared walking inOxfordon an average day to smoking over sixty light cigarettes.More precise comparisons can be collected from the UK Air Quality Archive[36]which allows the user to compare a cities management of pollutants against the national air quality objectives[37]set by DEFRA in 2000.Localized peak values are often cited, but average values are also important to human health. The UK National Air Quality Information Archive offers almost real-time monitoring of "current maximum" air pollution measurements for many UK towns and cities.[38]This source offers a wide range of constantly updated data, including:

* Hourly Mean Ozone (µg/m³)
* Hourly Mean Nitrogen dioxide (µg/m³)
* Maximum 15-Minute Mean Sulphur dioxide (µg/m³)
* 8-Hour Mean Carbon monoxide (mg/m³)
* 24-Hour Mean PM10(µg/m³ Grav Equiv)

DEFRA acknowledges that air pollution has a significant effect on health and has produced a simple banding index system[39]is used to create a daily warning system that is issued by theBBCWeather Service to indicate air pollution levels.[40]DEFRA has published guidelines for people suffering from respiratory and heart diseases.[41]
United States
Looking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.
Looking down from theHollywood Hills, withGriffith Observatoryon the hill in the foreground, air pollution is visible in downtownLos Angeleson a late afternoon.
In the 1960s, 70s, and 90s, theUnited States Congressenacted a series ofClean Air Actswhich significantly strengthened regulation of air pollution. Individual U.S. states, some European nations and eventually theEuropean Unionfollowed these initiatives. The Clean Air Act sets numerical limits on the concentrations of a basic group of air pollutants and provide reporting and enforcement mechanisms.In 1999, the United StatesEPAreplaced the Pollution Standards Index (PSI) with theAir Quality Index(AQI) to incorporate new PM2.5 and Ozone standards.The effects of these laws have been very positive. In the United States between 1970 and 2006, citizens enjoyed the following reductions in annual pollution emissions:[42]

* carbon monoxide emissions fell from 197 million tons to 89 million tons
* nitrogen oxide emissions fell from 27 million tons to 19 million tons
* sulfur dioxide emissions fell from 31 million tons to 15 million tons
* particulate emissions fell by 80%
* lead emissions fell by more than 98%

In an October 2006 letter toEPA, the agency's independent scientific advisors warned that the ozone smog standard “needs to be substantially reduced” and that there is “no scientific justification” for retaining the current, weaker standard. The scientists unanimously recommended a smog threshold of 60 to 70 ppb after they conducted an extensive review of the evidence.[43]TheEPAhas proposed, in June 2007, a new threshold of 75 ppb. This is less strict than the scientific recommendation, but is more strict the current standard.Some industries are lobbying to keep the current standards in place. Environmentalists and public health advocates are mobilizing to support the scientific recommendations.[citation needed]TheNational Ambient Air Quality Standardsare pollution thresholds which trigger mandatory remediation plans by state and local governments, subject to enforcement by the EPA.An outpouring of dust layered with man-made sulfates, smog, industrial fumes, carbon grit, and nitrates is crossing thePacific Oceanon prevailing winds from booming Asian economies in plumes so vast they alter the climate. Almost a third of the air overLos AngelesandSan Franciscocan be traced directly toAsia. With it comes up to three-quarters of the black carbon particulate pollution that reaches theWest Coast.[44]Libertarianstypically suggestpropertarianmethods of stopping pollution. They advocatestrict liabilitywhich would hold accountable anyone who causes polluted air to emanate into someone else's airspace. This offense would be considered aggression, and damages could be sought in court under thecommon law, possibly throughclass actionsuits.[45]Since in a libertarian society, highways would be privatized under a system offree market roads, the highway owners would also be held liable for pollution emanating from vehicles traveling along their property. This would give them a financial incentive to keep the worst polluters off of their roads.
Statistics
Most Polluted Cities
Most Polluted World Cities by PM[46]Particulate
matter,
μg/m³ (2004)City
169 Cairo, Egypt
150 Delhi, India
128 Kolkata, India(Calcutta)
125 Tianjin, China
123 Chongqing, China
109 Kanpur, India
109 Lucknow, India
104 Jakarta, Indonesia
101 Shenyang, China
Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are generally relatively lax or nonexistent. However, even populated areas in developed countries attain unhealthy levels of pollution.
Please helpimprove this sectionby expanding it.Further information might be found on thetalk pageor atrequests for expansion.(June 2008)

Carbon dioxide emissions
Total CO2emissions106Tons ofCO2per year:[47]

* United States: 2,790
* China: 2,680
* Russia: 661
* India: 583
* Japan: 400
* Germany: 356
* Australia: 226
* South Africa: 222
* United Kingdom: 212
* South Korea: 185

Per capita CO2emissionsTons of CO2per year per capita:[47]

* Australia: 10
* United States: 8.2
* United Kingdom: 3.2
* China: 1.8
* India: 0.5

Atmospheric dispersion
Main article:Atmospheric dispersion modeling
The basic technology for analyzing air pollution is through the use of a variety ofmathematical modelsfor predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

* Point sourcedispersion, used for industrial sources.
* Line sourcedispersion, used for airport androadway air dispersion modeling
* Area sourcedispersion, used forforest firesorduststorms
* Photochemicalmodels, used to analyze reactive pollutants that formsmog

Visualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models
Visualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models
The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses aGaussiandispersion model for buoyant pollution plumes to forecast the air pollutionisopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmosphericturbulence).[48][49]This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.Theroadway air dispersion modelwas developed starting in the late 1950s and early 1960s in response to requirements of theNational Environmental Policy Actand theU.S. Department of Transportation(then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group inLexington, Massachusetts, the ESL Inc. group inSunnyvale, Californiaand theCalifornia Air Resources Boardgroup inSacramento, California. The research of the ESL group received a boost with a contract award from theUnited States Environmental Protection Agencyto validate a line source model usingsulfur hexafluorideas a tracer gas. This program was successful in validating the line source model developed by ESL inc. Some of the earliest uses of the model were in court cases involving highway air pollution, theArlington, Virginiaportion ofInterstate 66and theNew Jersey Turnpikewidening project throughEast Brunswick, New Jersey.Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation inLos Angeles,California.
Environmental impacts
Main articles:Ocean acidificationandGreenhouse effect
Thegreenhouse effectis a phenomenon wherebygreenhouse gasescreate a condition in the upperatmospherecausing a trapping ofheatand leading to increased surface and lowertropospherictemperatures. It shares this property with manyother gases, the largest overallforcingon Earth coming fromwater vapour. Other greenhouse gases includemethane,hydrofluorocarbons,perfluorocarbons,chlorofluorocarbons,NOx, andozone. Many greenhouse gases, containcarbon, and some of that fromfossil fuels.This effect has been understood by scientists for about a century, and technological advancements during this period have helped increase the breadth and depth of data relating to the phenomenon. Currently, scientists are studying the role of changes in composition of greenhouse gases from natural and anthropogenic sources for the effect onclimate change.A number of studies have also investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause slightincreases in the acidity of ocean watersand the possible effects of this on marine ecosystems. However,carbonic acidis a very weak acid, and is utilized by marine organisms duringphotosynthesis.

Noise Pollution

Noise pollution (or environmental noise) is displeasing human- or machine-created sound that disrupts the activity or balance of human or animal life. A common form of noise pollution is from transportation, principally motor vehicles.[1] The word "noise" comes from the Latin word nausea meaning "seasickness", referring originally to nuisance noise.[2]
Contents
1 Sources of noise
2 Human health effects
3 Environmental effects
4 Mitigation and control of noise
5 Legal status
6 See also
7 References
8 External links
[edit]Sources of noise

See also: Roadway noise, Aircraft noise, and Noise measurement
The source of most noise worldwide is transportation systems, motor vehicle noise, but also including aircraft noise and rail noise.[3][1] Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area.
Other sources are car alarms, office equipment, factory machinery, construction work, appliances, power tools, lighting hum and audio entertainment systems.
Human health effects

Main article: Noise health effects
Noise health effects are both health and behavioural in nature. The unwanted sound is called noise. This unwanted sound can damage physiological and psychological health. Noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects.[4][5][6] Furthermore, stress and hypertension are the leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe depression and at times panic attacks.[5][7]
Chronic exposure to noise may cause noise-induced hearing loss. Older males exposed to significant occupational noise demonstrate significantly reduced hearing sensitivity than their non-exposed peers, though differences in hearing sensitivity decrease with time and the two groups are indistinguishable by age 79.[8] A comparison of Maaban tribesmen, who were insignificantly exposed to transportation or industrial noise, to a typical U.S. population showed that chronic exposure to moderately high levels of environmental noise contributes to hearing loss.[4]
High noise levels can contribute to cardiovascular effects and exposure to moderately high levels during a single eight hour period causes a statistical rise in blood pressure of five to ten points and an increase in stress[9] and vasoconstriction leading to the increased blood pressure noted above as well as to increased incidence of coronary artery disease.
Noise pollution is also a cause of annoyance. A 2005 study by Spanish researchers found that in urban areas households are willing to pay approximately four Euros per decibel per year for noise reduction.[10]
Environmental effects

Noise can have a detrimental effect on animals by causing stress, increasing risk of mortality by changing the delicate balance in predator/prey detection and avoidance, and by interfering with their use of sounds in communication especially in relation to reproduction and in navigation. Acoustic overexposure can lead to temporary or permanent loss of hearing.[11]
An impact of noise on animal life is the reduction of usable habitat that noisy areas may cause, which in the case of endangered species may be part of the path to extinction. One of the best known cases of damage caused by noise pollution is the death of certain species of beached whales, brought on by the loud sound of military sonar.[12]
Noise also makes species communicate louder, which is called Lombard vocal response.[13] Scientists and researchers have conducted experiments that show whales' song length is longer when submarine-detectors are on.[14] If creatures don't "speak" loud enough, their voice will 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 species' voice, causing the whole ecosystem to eventually speak louder.
Zebra finches become less faithful to their partners when exposed to traffic noise. This could alter a population's evolutionary trajectory by selecting "sexy" traits, sapping resources normally devoted to other activities and thus lead to profound genetic and evolutionary consequences.[15]
[edit]Mitigation and control of noise

Main article: Noise mitigation


The sound tube in Melbourne, Australia, designed to reduce roadway noise without detracting from the area's aesthetics.
Technology to mitigate or remove noise can be applied as follows:
There are a variety of strategies for mitigating roadway noise including: use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy duty vehicles, use of traffic controls that smooth vehicle flow to reduce braking and acceleration, and tyre design. An important factor in applying these strategies is a computer model for roadway noise, that is capable of addressing local topography, meteorology, traffic operations and hypothetical mitigation. Costs of building-in mitigation can be modest, provided these solutions are sought in the planning stage of a roadway project.
Aircraft noise can be reduced to some extent by design of quieter jet engines, which was pursued vigorously in the 1970s and 1980s. This strategy has brought limited but noticeable reduction of urban sound levels. Reconsideration of operations, such as altering flight paths and time of day runway use, have demonstrated benefits for residential populations near airports. FAA sponsored residential retrofit (insulation) programs initiated in the 1970s has also enjoyed success in reducing interior residential noise in thousands of residences across the United States.
Exposure of workers to Industrial noise has been addressed since the 1930s. Changes include redesign of industrial equipment, shock mounting assemblies and physical barriers in the workplace.
Legal status

Main article: Noise regulation
Governments up until the 1970s viewed noise as a "nuisance" rather than an environmental problem. In the United States there are federal standards for highway and aircraft noise; states and local governments typically have very specific statutes on building codes, urban planning and roadway development. In Canada and the EU there are few national, provincial, or state laws that protect against noise.
Noise laws and ordinances vary widely among municipalities and indeed do not even exist in some cities. An ordinance may contain a general prohibition against making noise that is a nuisance, or it may set out specific guidelines for the level of noise allowable at certain times of the day and for certain activities.
Most city ordinances prohibit sound above a threshold intensity from trespassing over property line at night, typically between 10 p.m. and 6 a.m., and during the day restricts it to a higher sound level; however, enforcement is uneven. Many municipalities do not follow up on complaints. Even where a municipality has an enforcement office, it may only be willing to issue warnings, since taking offenders to court is expensive.
Many conflicts over noise pollution are handled by negotiation between the emitter and the receiver. Escalation procedures vary by country, and may include action in conjunction with local authorities, in particular the police. Noise pollution often persists because only five to ten percent of people affected by noise will lodge a formal complaint. Many people are not aware of their legal right to quiet and do not know how to register a complaint.




khatriahm
khatriahm 		Latest page update: made by khatriahm , Sep 18 2008, 12:28 PM EDT (about this update About This Update khatriahm Moved from: Ask Home - khatriahm

No content added or deleted.
- complete history)
Keyword tags: of Any thing
More Info: links to this page

Threads for this page

There are no threads for this page.  Be the first to start a new thread.