Pollution

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Air pollution from World War II weapon production in Alabama

Pollution is the introduction of contaminants into a natural environment that causes instability,
disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms.[1]
Pollution can take the form of chemical substances or energy, such as noise, heat, or light.
Pollutants, the elements of pollution, can be foreign substances or energies, or naturally
occurring; when naturally occurring, they are considered contaminants when they exceed natural
levels. Pollution is often classed as point source or nonpoint source pollution. The Blacksmith
Institute issues annually a list of the world's worst polluted places. In the 2007 issues the ten top
nominees are located in Azerbaijan, China, India, Peru, Russia, Ukraine, and Zambia.[2]

Content
hide 1 Ancient cultures

 2 Official acknowledgement
 3 Modern awareness
 4 Forms of pollution
 5 Pollutants
 6 Sources and causes
 7 Effects
o 7.1 Human health
o 7.2 Environment
o 7.3 Environmental health information
 8 Regulation and monitoring
 9 Pollution control
o 9.1 Practices
o 9.2 Pollution control devices
 10 Perspectives
 11 Greenhouse gases and global warming
 12 See also
 13 References
 14 External links

[edit] Ancient cultures

Air pollution has always been with us. According to a 1983 article in the journal Science, "soot
found on ceilings of prehistoric caves provides ample evidence of the high levels of pollution
that was associated with inadequate ventilation of open fires."[3] The forging of metals appears to
be a key turning point in the creation of significant air pollution levels outside the home. Core
samples of glaciers in Greenland indicate increases in pollution associated with Greek, Roman
and Chinese metal production.[4]

[edit] Official acknowledgement

King Edward I of England banned the burning of sea-coal by proclamation in London in 1272,
after its smoke had become a problem.[5][6] But the fuel was so common in England that this
earliest of names for it was acquired because it could be carted away from some shores by the
wheelbarrow. Air pollution would continue to be a problem in England, especially later during
the industrial revolution, and extending into the recent past with the Great Smog of 1952. This
same city also recorded one of the earlier extreme cases of water quality problems with the Great
Stink on the Thames of 1858, which led to construction of the London sewerage system soon
afterward.

It was the industrial revolution that gave birth to environmental pollution as we know it today.
The emergence of great factories and consumption of immense quantities of coal and other fossil
fuels gave rise to unprecedented air pollution and the large volume of industrial chemical
discharges added to the growing load of untreated human waste. Chicago and Cincinnati were
the first two American cities to enact laws ensuring cleaner air in 1881. Other cities followed
around the country until early in the 20th century, when the short lived Office of Air Pollution
was created under the Department of the Interior. Extreme smog events were experienced by the
cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as another public
reminder.[7]

[edit] Modern awareness

Pollution became a popular issue after World War II, due to radioactive fallout from atomic
warfare and testing. Then a non-nuclear event, The Great Smog of 1952 in London, killed at
least 4000 people.[8] This prompted some of the first major modern environmental legislation,
The Clean Air Act of 1956.

Pollution began to draw major public attention in the United States between the mid-1950s and
early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water
Act and the National Environmental Policy Act.

Bad bouts of local pollution helped increase consciousness. PCB dumping in the Hudson River
resulted in a ban by the EPA on consumption of its fish in 1974. Long-term dioxin contamination
at Love Canal starting in 1947 became a national news story in 1978 and led to the Superfund
legislation of 1980. Legal proceedings in the 1990s helped bring to light Chromium-6 releases in
California--the champions of whose victims became famous. The pollution of industrial land
gave rise to the name brownfield, a term now common in city planning. DDT was banned in
most of the developed world after the publication of Rachel Carson's Silent Spring.
The development of nuclear science introduced radioactive contamination, which can remain
lethally radioactive for hundreds of thousands of years. Lake Karachay, named by the
Worldwatch Institute as the "most polluted spot" on earth, served as a disposal site for the Soviet
Union thoroughout the 1950s and 1960s. Second place may go to the area of Chelyabinsk
U.S.S.R. (see reference below) as the "Most polluted place on the planet".[citation needed]

Nuclear weapons continued to be tested in the Cold War, sometimes near inhabited areas,
especially in the earlier stages of their development. The toll on the worst-affected populations
and the growth since then in understanding about the critical threat to human health posed by
radioactivity has also been a prohibitive complication associated with nuclear power. Though
extreme care is practiced in that industry, the potential for disaster suggested by incidents such as
those at Three Mile Island and Chernobyl pose a lingering specter of public mistrust. One legacy
of nuclear testing before most forms were banned has been significantly raised levels of
background radiation.[citation needed]

International catastrophes such as the wreck of the Amoco Cadiz oil tanker off the coast of
Brittany in 1978 and the Bhopal disaster in 1984 have demonstrated the universality of such
events and the scale on which efforts to address them needed to engage. The borderless nature of
atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level
with the issue of global warming. Most recently the term persistent organic pollutant (POP) has
come to describe a group of chemicals such as PBDEs and PFCs among others. Though their
effects remain somewhat less well understood owing to a lack of experimental data, they have
been detected in various ecological habitats far removed from industrial activity such as the
Arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of
widespread use.

Growing evidence of local and global pollution and an increasingly informed public over time
have given rise to environmentalism and the environmental movement, which generally seek to
limit human impact on the environment.

[edit] Forms of pollution

The Lachine Canal in Montreal Canada, is polluted.

The major forms of pollution are listed below along with the particular pollutants relevant to
each of them:

 Air pollution, the release of chemicals and particulates into the atmosphere. Common
gaseous air pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons
(CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical
ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight.
Particulate matter, or fine dust is characterized by their micrometre size PM10 to PM2.5.

 Light pollution, includes light trespass, over-illumination and astronomical interference.

  Littering
 Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as
well as high-intensity sonar.
 Soil contamination occurs when chemicals are released intentionally, by spill or
underground leakage. Among the most significant soil contaminants are hydrocarbons,
heavy metals, MTBE,[9] herbicides, pesticides and chlorinated hydrocarbons.
 Radioactive contamination, resulting from 20th century activities in atomic physics, such
as nuclear power generation and nuclear weapons research, manufacture and deployment.
(See alpha emitters and actinides in the environment.)
 Thermal pollution, is a temperature change in natural water bodies caused by human
influence, such as use of water as coolant in a power plant.
 Visual pollution, which can refer to the presence of overhead power lines, motorway
billboards, scarred landforms (as from strip mining), open storage of trash or municipal
solid waste.
 Water pollution, by the discharge of wastewater from commercial and industrial waste
(intentionally or through spills) into surface waters; discharges of untreated domestic
sewage, and chemical contaminants, such as chlorine, from treated sewage; release of
waste and contaminants into surface runoff flowing to surface waters (including urban
runoff and agricultural runoff, which may contain chemical fertilizers and pesticides);
waste disposal and leaching into groundwater; eutrophication and littering.

[edit] Pollutants
Main article: Pollutant

A pollutant is a waste material that pollutes air, water or soil. Three factors determine the
severity of a pollutant: its chemical nature, the concentration and the persistence.

[edit] Sources and causes

Air pollution produced by ships may alter clouds, affecting global temperatures.

Air pollution comes from both natural and man made sources. Though globally man made
pollutants from combustion, construction, mining, agriculture and warfare are increasingly
significant in the air pollution equation.[10]

Motor vehicle emissions are one of the leading causes of air pollution.[11][12][13] China, United
States, Russia, Mexico, and Japan are the world leaders in air pollution emissions. Principal
stationary pollution sources include chemical plants, coal-fired power plants, oil refineries,[14]
petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy
cows, pigs, poultry, etc.), PVC factories, metals production factories, plastics factories, and other
heavy industry. Agricultural air pollution comes from contemporary practices which include
clear felling and burning of natural vegetation as well as spraying of pesticides and herbicides[15]
About 400 million metric tons of hazardous wastes are generated each year.[16] The United States
alone produces about 250 million metric tons.[17] Americans constitute less than 5% of the
world's population, but produce roughly 25% of the world’s CO2,[18] and generate approximately
30% of world’s waste.[19][20] In 2007, China has overtaken the United States as the world's biggest
producer of CO2.[21]

In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC),

representing the work of 2,500 scientists, economists, and policymakers from more than 120
countries, said that humans have been the primary cause of global warming since 1950. Humans
have ways to cut greenhouse gas emissions and avoid the consequences of global warming, a
major climate report concluded. But in order to change the climate, the transition from fossil
fuels like coal and oil needs to occur within decades, according to the final report this year from
the UN's Intergovernmental Panel on Climate Change (IPCC).[22]

Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy metals
(such as chromium, cadmium–found in rechargeable batteries, and lead–found in lead paint,
aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. In 2001 a
series of press reports culminating in a book called Fateful Harvest unveiled a widespread
practice of recycling industrial byproducts into fertilizer, resulting in the contamination of the
soil with various metals. Ordinary municipal landfills are the source of many chemical
substances entering the soil environment (and often groundwater), emanating from the wide
variety of refuse accepted, especially substances illegally discarded there, or from pre-1970
landfills that may have been subject to little control in the U.S. or EU. There have also been
some unusual releases of polychlorinated dibenzodioxins, commonly called dioxins for
simplicity, such as TCDD.[23]

Pollution can also be the consequence of a natural disaster. For example, hurricanes often
involve water contamination from sewage, and petrochemical spills from ruptured boats or
automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or
refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers,
can produce widespread and potentially hazardous releases when accidents occur.

In the case of noise pollution the dominant source class is the motor vehicle, producing about
ninety percent of all unwanted noise worldwide.

[edit] Effects
[edit] Human health

Overview of main health effects on humans from some common types of pollution.[24][25][26]

Adverse air quality can kill many organisms including humans. Ozone pollution can cause
respiratory disease, cardiovascular disease, throat inflammation, chest pain, and congestion.
Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of
drinking water by untreated sewage in developing countries. An estimated 700 million Indians
have no access to a proper toilet, and 1,000 Indian children die of diarrhoeal sickness every day.
[27]
Nearly 500 million Chinese lack access to safe drinking water.[28] 656,000 people die
prematurely each year in China because of air pollution. In India, air pollution is believed to
cause 527,700 fatalities a year.[29] Studies have estimated that the number of people killed
annually in the US could be over 50,000.[30]

Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood
pressure, stress, and sleep disturbance. Mercury has been linked to developmental deficits in
children and neurologic symptoms. Older people are majorly exposed to diseases induced by air
pollution. Those with heart or lung disorders are under additional risk. Children and infants are
also at serious risk. Lead and other heavy metals have been shown to cause neurological
problems. Chemical and radioactive substances can cause cancer and as well as birth defects.

[edit] Environment

Pollution has been found to be present widely in the environment. There are a number of effects
of this:

 Biomagnification describes situations where toxins (such as heavy metals) may pass
through trophic levels, becoming exponentially more concentrated in the process.
 Carbon dioxide emissions cause ocean acidification, the ongoing decrease in the pH of
the Earth's oceans as CO2 becomes dissolved.
 The emission of greenhouse gases leads to global warming which affects ecosystems in
many ways.
 Invasive species can out compete native species and reduce biodiversity. Invasive plants
can contribute debris and biomolecules (allelopathy) that can alter soil and chemical
compositions of an environment, often reducing native species competitiveness.
 Nitrogen oxides are removed from the air by rain and fertilise land which can change the
species composition of ecosystems.
 Smog and haze can reduce the amount of sunlight received by plants to carry out
photosynthesis and leads to the production of tropospheric ozone which damages plants.
 Soil can become infertile and unsuitable for plants. This will affect other organisms in the
food web.
 Sulphur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of
soil.

[edit] Environmental health information

The Toxicology and Environmental Health Information Program (TEHIP)[31] at the United States
National Library of Medicine (NLM) maintains a comprehensive toxicology and environmental
health web site that includes access to resources produced by TEHIP and by other government
agencies and organizations. This web site includes links to databases, bibliographies, tutorials,
and other scientific and consumer-oriented resources. TEHIP also is responsible for the
Toxicology Data Network (TOXNET®)[32] an integrated system of toxicology and environmental
health databases that are available free of charge on the web.
TOXMAP is a Geographic Information System (GIS) that is part of TOXNET. TOXMAP uses
maps of the United States to help users visually explore data from the United States
Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund Basic
Research Programs.

[edit] Regulation and monitoring

Main article: Regulation and monitoring of pollution

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.

[edit] Pollution control

Pollution control is a term used in environmental management. It means the control of emissions
and effluents into air, water or soil. Without pollution control, the waste products from
consumption, heating, agriculture, mining, manufacturing, transportation and other human
activities, whether they accumulate or disperse, will degrade the environment. In the hierarchy of
controls, pollution prevention and waste minimization are more desirable than pollution control.
In the field of land development, low impact development is a similar technique for the
prevention of urban runoff.

[edit] Practices

 recycling

[edit] Pollution control devices

 Dust collection systems

o Baghouses
o Cyclones
o Electrostatic precipitators
 Scrubbers
o Baffle spray scrubber
o Cyclonic spray scrubber
o Ejector venturi scrubber
o Mechanically aided scrubber
o Spray tower
o Wet scrubber
 Sewage treatment
o Sedimentation (Primary treatment)
o Activated sludge biotreaters (Secondary treatment; also used for industrial
wastewater)
 o Aerated lagoons
o Constructed wetlands (also used for urban runoff)
 Industrial wastewater treatment
o API oil-water separators[14][33]
o Biofilters
o Dissolved air flotation (DAF)
o Powdered activated carbon treatment
o Ultrafiltration
 Vapor recovery systems

[edit] Perspectives
The earliest precursor of pollution generated by life forms would have been a natural function of
their existence. The attendant consequences on viability and population levels fell within the
sphere of natural selection. These would have included the demise of a population locally or
ultimately, species extinction. Processes that were untenable would have resulted in a new
balance brought about by changes and adaptations. At the extremes, for any form of life,
consideration of pollution is superseded by that of survival.

For humankind, the factor of technology is a distinguishing and critical consideration, both as an
enabler and an additional source of byproducts. Short of survival, human concerns include the
range from quality of life to health hazards. Since science holds experimental demonstration to
be definitive, modern treatment of toxicity or environmental harm involves defining a level at
which an effect is observable. Common examples of fields where practical measurement is
crucial include automobile emissions control, industrial exposure (e.g. Occupational Safety and
Health Administration (OSHA) PELs), toxicology (e.g. LD50), and medicine (e.g. medication and
radiation doses).

"The solution to pollution is dilution", is a dictum which summarizes a traditional approach to

pollution management whereby sufficiently diluted pollution is not harmful.[34][35] It is well-suited
to some other modern, locally scoped applications such as laboratory safety procedure and
hazardous material release emergency management. But it assumes that the dilutant is in
virtually unlimited supply for the application or that resulting dilutions are acceptable in all
cases.

Such simple treatment for environmental pollution on a wider scale might have had greater merit
in earlier centuries when physical survival was often the highest imperative, human population
and densities were lower, technologies were simpler and their byproducts more benign. But these
are often no longer the case. Furthermore, advances have enabled measurement of concentrations
not possible before. The use of statistical methods in evaluating outcomes has given currency to
the principle of probable harm in cases where assessment is warranted but resorting to
deterministic models is impractical or unfeasible. In addition, consideration of the environment
beyond direct impact on human beings has gained prominence.
Yet in the absence of a superseding principle, this older approach predominates practices
throughout the world. It is the basis by which to gauge concentrations of effluent for legal
release, exceeding which penalties are assessed or restrictions applied. The regressive cases are
those where a controlled level of release is too high or, if enforceable, is neglected. Migration
from pollution dilution to elimination in many cases is confronted by challenging economical
and technological barriers.

[edit] Greenhouse gases and global warming

Main article: Global warming

Historical and projected CO2 emissions by country.

Source: Energy Information Administration.[36][37]

Carbon dioxide, while vital for photosynthesis, is sometimes referred to as pollution, because
raised levels of the gas in the atmosphere are affecting the Earth's climate. Disruption of the
environment can also highlight the connection between areas of pollution that would normally be
classified separately, such as those of water and air. Recent studies have investigated the
potential for long-term rising levels of atmospheric carbon dioxide to cause slight but critical
increases in the acidity of ocean waters, and the possible effects of this on marine ecosystems.