POLLUTION Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution.
History Air pollution has always accompanied civilizations. Pollution started from prehistoric times when man created the first fires. 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." Metal forging 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, but at that time the pollution was comparatively small and could be handled by nature.
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Urban pollution The burning of coal and wood, and the presence of many horses in concentrated areas made the cities the cesspools of pollution. The Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply. King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem. 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.
It was the industrial revolution that gave birth to environmental pollution as we know it today. London 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. Pollution issues escalated as population growth far exceeded view ability of neighborhoods to handle their waste problem. Reformers began to demand sewer systems, and clean water. In 1870, the sanitary conditions in Berlin were among the worst in Europe. August Bebel recalled conditions before a modern sewer system was built in the late 1870s:
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"Waste-water from the houses collected in the gutters running alongside the curbs and emitted a truly fearsome smell. There were no public toilets in the streets or squares. Visitors, especially women, often became desperate when nature called. In the public buildings the sanitary facilities were unbelievably primitive....As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870." The primitive conditions were intolerable for a world national capital, and the Imperial German government brought in its scientists, engineers and urban planners to not only solve the deficiencies but to forge Berlin as the world's model city. A British expert in 1906 concluded that Berlin represented "the most complete application of science, order and method of public life," adding "it is a marvel of civic administration, the most modern and most perfectly organized city that there is. 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.
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Smog Pollution in Taiwan Severe incidents of 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. The pollution of industrial land gave rise to the name brownfield, a term now common in city planning. 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 throughout the 1950s and 1960s. Chelyabinsk, Russia, is considered the "Most polluted place on the planet". Nuclear weapons continued to be tested in the Cold War, 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. Worldwide publicity has been intense on those disasters. Widespread support for test ban treaties has ended almost all nuclear testing in the atmosphere.
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 4
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. Pollution introduced by light at night is becoming a global problem, more severe in urban centres, but nonetheless contaminating also large territories, far away from towns.
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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.
Forms of pollution Blue drain and yellow fish symbol used by the UK Environment Agency to raise awareness of the ecological impacts of contaminating surface drainage. The major forms of pollution are listed below along with the particular contaminant relevant to each of them: 
Air pollution: the release of chemicals and particulates into the atmosphere. Common gaseous 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.
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Light pollution: includes light trespass, over-illumination and astronomical interference.
Littering: the criminal throwing of inappropriate man-made objects, unremoved, onto public and private properties.
Noise pollution: which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar.
Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, 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, municipal solid waste or space debris.
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.
Plastic pollution: involves the accumulation of plastic products in the environment that adversely affects wildlife, wildlife habitat, or humans.
Sources and causes Air pollution produced by ships may alter clouds, affecting global temperatures. Air pollution comes from both natural and human-made (anthropogenic) sources. However, globally human-made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation.
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Motor vehicle emissions are one of the leading causes of air pollution. China, United States, Russia, India Mexico, and Japan are the world leaders in air pollution emissions. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries, 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.
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About 400 million metric tons of hazardous wastes are generated each year. The United States alone produces about 250 million metric tons. Americans constitute less than 5% of the world's population, but produce roughly 25% of the world’s CO2, and generate approximately 30% of world’s waste. In 2007, China has overtaken the United States as the world's biggest producer of CO2, while still far behind based on per capita pollution - ranked 78th among the world's nations.
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 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). 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 9
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.
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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. Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur. In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted noise worldwide.
Effects Human health Adverse air quality can kill many organisms including humans. Ozone pollution can cause respiratory disease, cardiovascular disease, throat inflammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries. An estimated 500 million Indians have no access to a proper toilet. Over ten million people in India fell ill with waterborne illnesses in 2013, and 1,535 people died, most of them children. Nearly 500 million Chinese lack access to safe drinking water. A 2010 analysis estimated that 1.2 million people died prematurely each year in China because of air pollution. The WHO estimated in 2007 that air pollution causes half a million deaths per year in India. Studies have estimated that the number of people killed annually in the United States could be over 50,000.
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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 at 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.
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.
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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.
Sulfur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of soil.
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Air Pollution Pollutants in the air aren't always visible and come from many different sources. Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution—some visible, some invisible—that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.
What Is Air Pollution? Air pollution refers to the release of pollutants into the air that are detrimental to human health and the planet as a whole.
Air pollution (say: po-loo-shun) occurs when gases, dust particles, fumes (or smoke) or odour are introduced into the atmosphere in a way that makes it harmful to humans, animals and plant. This is because the air becomes dirty (contaminated or unclean). 14
The Earth is surrounded by a blanket of air (made up of various gases) called the atmosphere. The atmosphere helps protect the Earth and allow life to exist. Without it, we would be burned by the intense heat of the sun during the day or frozen by the very low temperatures at night.
Any additional gas, particles or odours that are introduced into the air (either by nature or human activity) to distort this natural balance and cause harm to living things can be called air pollution.
Air pollution for children Things that pollute the air are called pollutants. Examples of pollutants include nitrogen oxides, carbon monoxides, hydrocarbons, sulphur oxides (usually from factories), sand or dust particles, and organic compounds that can evaporate and enter the atmosphere.
WHAT CAUSES AIR POLLUTION? “Burning fossil fuels releases gases and chemicals into the air.� And in an especially destructive feedback loop, air pollution not only contributes to climate change but is also exacerbated by it.
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“Air pollution in the form of carbon dioxide and methane raises the earth’s temperature,”. “Another type of air pollution is then worsened by that increased heat: Smog forms when the weather is warmer and there’s more ultraviolet radiation.” Climate change also increases the production of allergenic air pollutants including mold (thanks to damp conditions caused by extreme weather and increased flooding) and pollen (due to a longer pollen season and more pollen production). Air pollution can result from both human and natural actions. Natural events that pollute the air include forest fires, volcanic eruptions, wind erosion,
pollen
dispersal,
evaporation
of
organic
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compounds
and
natural
radioactivity.
HUMAN ACTIVITIES THAT RESULT IN AIR POLLUTION INCLUDE: 1. Emissions from industries and manufacturing activities. Consider a typical manufacturing plant: You will notice that there are long tubes (called chimneys) erected high into the air, with lots of smoke and fumes coming out of it. Waste incinerators, manufacturing industries and power plants emit high levels of carbon monoxide, organic compounds, and chemicals into the air. This happens almost everywhere that people live. Petroleum refineries also release lots of hydrocarbons into the air.
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2. Burning Fossil Fuels After the industrial age, transportation has become a key part of our lives. Cars and heavy duty trucks, trains, shipping vessels and airplanes all burn lots of fossil fuels to work. Emissions from automobile engines contain both primary and secondary pollutants. This is a major cause of pollution and one that is very difficult to manage. This is because humans rely heavily on vehicles and engines for transporting people, good and services.
Fumes from car exhausts contain dangerous gases such as carbon monoxide, oxides of nitrogen, hydrocarbons and particulates. On their own, they cause great harm to people who breathe them. Additionally, they react with environmental gases to create further toxic gases.
3. Household and Farming Chemicals Crop dusting, fumigating homes, household cleaning products or painting supplies, over the counter insect/pest killers, fertilizer dust emit harmful chemicals into the air and cause pollution. In many cases, when we use these chemicals at home or offices with no or little ventilation, we may fall ill if we breathe them.
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THERE ARE TWO TYPES OF POLLUTANTS: Primary pollutants are those gases or particles that are pumped into the air to make it unclean. They include carbon monoxide from automobile (cars) exhausts and sulfur dioxide from the combustion of coal.
Secondary pollutants: When pollutants in the air mix up in a chemical reaction, they form an even more dangerous chemical. Photochemical smog is an example of this, and is a secondary pollutant. Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas. In the past 150 years, such activities have pumped enough carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years.
What are the common air pollutants around?
Carbon Monoxide (CO) Fuel combustion from vehicles and engines. Reduces the amount of oxygen reaching the body’s organs and tissues; aggravates heart disease, resulting in chest pain and other symptoms. 19
Ground-level Ozone (O3) Secondary pollutant formed by chemical reaction of volatile organic compounds (VOCs) and NOx in the presence of sunlight. Decreases lung function and causes respiratory symptoms, such as coughing and shortness of breath, and also makes asthma and other lung diseases get worse.
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Lead (Pb) Smelters (metal refineries) and other metal industries; combustion of leaded gasoline in piston engine aircraft; waste incinerators (waste burners), and battery manufacturing. Damages the developing nervous system, resulting in IQ loss and impacts on learning, memory, and behavior in children. Cardiovascular and renal effects in adults and early effects related to anaemia.
Nitrogen Dioxide (NO2) Fuel combustion (electric utilities, big industrial boilers, vehicles) and wood burning. Worsens lung diseases leading to respiratory symptoms, increased susceptibility to respiratory infection. Particulate Matter (PM) This is formed through chemical reactions, fuel combustion (e.g., burning coal, wood, diesel), industrial processes, farming (plowing, field burning), and unpaved roads or during road constructions. Short-term exposures can worsen heart or lung diseases and cause respiratory problems. Long-term exposures can cause heart or lung disease and sometimes premature deaths. Sulfur Dioxide (SO2) SO2 comes from fuel combustion (especially high-sulfur coal); electric utilities and industrial processes as well as natural occurences like volcanoes. Aggravates asthma and makes breathing difficult. It also contributes to particle formation with associated health effects.
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EFFECTS OF AIR POLLUTION Acidification: Chemical reactions involving air pollutants can create acidic compounds which can cause harm to vegetation and buildings. Sometimes, when an air pollutant, such as sulfuric acid combines with the water droplets that make up clouds, the water droplets become acidic, forming acid rain. When acid rain falls over an area, it can kill trees and harm animals, fish, and other wildlife.
Acid rain destroys the leaves of plants. When acid rain infiltrates into soils, it changes the chemistry of the soil making it unfit for many living things that depend on the soil as a habitat or for nutrition. Acid rain also changes the chemistry of the lakes and streams that the rainwater flows into, harming fish and other aquatic life.
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Smog and soot These two are the most prevalent types of air pollution. Smog, or “ground-level ozone,” as it is more wonkily called, occurs when emissions from combusting fossil fuels react with sunlight. Soot, or “particulate matter,” is made up of tiny particles of chemicals, soil, smoke, dust, or allergens, in the form of gas or solids, that are carried in the air. The EPA’s “Plain English Guide to the Clean Air Act” states, “In many parts of the United States, pollution has reduced the distance and clarity of what we see by 70 percent.”
The sources of smog and soot are similar. “Both come from cars and trucks, factories, power plants, incinerators, engines—anything that combusts fossil fuels such as coal, gas, or natural gas,” Walke says. 23
The tiniest airborne particles in soot—whether they’re in the form of gas or solids—are especially dangerous because they can penetrate the lungs and bloodstream and worsen bronchitis, lead to heart attacks, and even hasten death.
Smog can irritate the eyes and throat and also damage the lungs—especially of people who work or exercise outside, children, and senior citizens. It’s even worse for people who have asthma or allergies— these extra pollutants only intensify their symptoms and can trigger asthma attacks.
Hazardous air pollutants These are either deadly or have severe health risks even in small amounts. Almost 200 are regulated by law; some of the most common are mercury, lead, dioxins, and benzene. “These are also most often emitted during
gas
or
coal
combustion,
incinerating, or in the case of benzene, found in gasoline,”.
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Benzene, classified as a carcinogen by the EPA, can cause eye, skin, and lung irritation in the short term and blood disorders in the long term. Dioxins, more typically found in food but also present in small amounts in the air, can affect the liver in the short term and harm the immune, nervous, and endocrine systems, as well as reproductive functions. Lead in large amounts can damage children’s brains and kidneys, and even in small amounts it can affect children’s IQ and ability to learn. Mercury affects the central nervous system. Polycyclic aromatic hydrocarbons, or PAHs, are toxic components of traffic exhaust and wildfire smoke. In large amounts, they have been linked to eye and lung irritation, blood and liver issues, and even cancer. In one recent study, the children of mothers who’d had higher PAH exposure during pregnancy had slower brain processing speeds and worse symptoms of ADHD.
Greenhouse gases By trapping the earth’s heat in the atmosphere, greenhouse gases lead to warmer temperatures and all the hallmarks of climate change: rising sea levels, more extreme weather, heat-related deaths, and increasing transmission of infectious diseases like Lyme. According to a 2014 EPA study, carbon dioxide was responsible for 81 percent of the country’s total greenhouse gas emissions, and methane made up 11
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percent. “Carbon dioxide comes from combusting fossil fuels, and methane comes from natural and industrial sources, including the large amounts that are released during oil and gas drilling,”.
“We emit far larger amounts of carbon dioxide, but methane is significantly more potent, so it’s also very destructive.” Another class of greenhouse gases, hydrofluorocarbons (HFCs), are thousands of times more powerful than carbon dioxide in their ability to trap heat. In October 2016, more than 140 countries reached an agreement to reduce the use of these chemicals—which are used in air conditioners and refrigerators—and find greener alternatives over time. Carbon dioxide is not normally considered to be a pollutant, but there is considerable evidence that its concentration in the atmosphere has increased appreciably during the last century, from about 0.030% to about 0.038%, largely due to the proliferation of industry, coal-fired electricity generation, and the enormous use of land and air transport, activities that are based on the combustion of fossil fuels. As a rule of thumb, every kilogram of a fossil fuel produces about 3 kilograms of carbon dioxide. The more developed a country is, the more carbon dioxide it produces. The United States, for example, produces more than half the total amount of carbon dioxide emitted anually, and there is every indication that it is soon to be overtaken by China. Therefore, the prospects for a dramatic world-wide reduction in carbon dioxide emission are not at all good.
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Most of the radiation coming from the sun is in the form of visible light, about half of which can penetrate the atmosphere and reach the surface of the earth and be absorbed.
about 51% is absorbed by the
earth’s surface.
about 20%, is reflected and
scattered back by clouds
about 6% is scattered by the atmosphere
about 19% is absorbed by the atmosphere, largely by clouds
about 4% is reflected back by the earth’s surface
The radiation absorbed by the earth’s surface during the day heats up the earth’s surface (including the oceans). This means that the earth’s surface can radiate some of this heat back into space at night in the form of infrared radiation. However, the so-called GREENHOUSE GASES, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water (H2O), and to a lesser extent, ozone (O3) (as an industrial pollutant), absorb some of this infrared radiation, which is then re-emitted back to earth. The net result is that the earth is warmer than it would be in the absence of such gases. It has been calculated that this greenhouse effect increases the earth’s temperature by about 30 ºC, making the planet liveable to humans. So, the greenhouse effect is normal and beneficial. The problem arises due to the increase in the greenhouse gases, notably carbon dioxide, which leads to global warming and climate changes. There is much evidence that global temperatures have increased appreciably in the last 200 years or so, and already, glaciers and the ice caps are melting, and the ocean levels are rising. If this continues unchecked, serious damage will be done to the planet, with catastrophic consequences.
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It should be pointed out that not everyone is convinced, and some countries, notably the United States, have so far (end of 2011) not ratified the Kyoto Protocol, established in 1997 to attempt to reduce greenhouse gas emissions. South Africa is one of the countries that support the Protocol. The main argument used against carbon dioxide being a prime cause of global warming is the fact that the energy output from the sun is not constant, and depends largely on cyclical sunspot activity.
Pollen and mold Mold and allergens from trees, weeds, and grass are also carried in the air, are exacerbated by climate change, and can be hazardous to health. They are not regulated by the government and are less directly connected to human actions, but they can be considered air pollution. “When homes, schools, or businesses get water damage, mold can grow and can produce allergenic airborne pollutants,”. “Mold exposure can precipitate asthma attacks or an allergic response, and some molds can even produce toxins that would be dangerous for anyone to inhale.”
Pollen allergies are worsening because of climate change. “Lab and field studies are showing that the more carbon dioxide pollen-producing plants—especially ragweed—are grown in, the bigger they grow and the more pollen they produce,” .“Climate change also extends the pollen production season, and some 28
studies are beginning to suggest that ragweed pollen itself might be becoming a more potent allergen.� That means more people will suffer runny noses, fevers, itchy eyes, and other symptoms.
Acid rain In addition to the release of carbon dioxide into the atmosphere, the combustion of fossil fuels also produces sulphur dioxide, SO2, and oxides of nitrogen, such as nitrogen dioxide, NO2. These arise in the first place from sulphur in the fuel (coal, petrol) and from the oxidation of nitrogen taking place at the high temperatures involved in the combustion process. Motor cars exhaust fumes contain appreciable amounts of nitrogen oxides. Both oxides cause respiratory problems of varying severity in humans. In the atmosphere, both SO2 and NO2 will form acids in the presence of oxygen and moisture, and these acids dissolve in raindrops, falling to the earth in the form of "acid rain". Acid rain kills trees and fish, and gradually dissolves stone monuments.
Ozone layer depletion Ozone, O3, is an allotrope of oxygen ( the STRATOSPHERE (
), present in an upper layer of the atmosphere, called
). It is produced by the action of cosmic radiation on oxygen molecules:
and is present in very small amounts, less than 7x10-6 % by volume. Ozone functions as a sun screen, absorbing harmful ultraviolet rays from the sun. Chlorofluorocarbons (CFCs) are man-made chemicals that contain the elements carbon, chlorine and fluorine. They were used extensively as propellants in aerosol cans, refrigerants and in the manufacture of foam plastics and printed circuit boards. Being very stable substances, once they enter the atmosphere, they survive for a long time and eventually diffuse into the stratosphere, where they can
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undergo decomposition to form chlorine atoms:
In turn, these chlorine atoms react with ozone to form oxygen and chlorine monoxide, ClO.
THE OZONE HOLE OVER ANTARCTICA, 11 SEPTEMBER 2003 (SOURCE: NASA)
As a result, the ozone layer becomes depleted. A so-called OZONE HOLE develops seasonally over Antarctica, and consequently, the surface of the earth experiences increased levels of ultraviolet radiation, most noticeably in the Southern Hemisphere. The results are increased levels of skin cancers and eye diseases in humans. The use of CFCs is banned by an international agreement called the "Montreal Protocol".
Eutrophication: Rain can carry and deposit the Nitrogen in some pollutants on rivers and soils. This will adversely affect the nutrients in the soil and water bodies. This can result in algae growth in lakes and water bodies, and make conditions for other living organism harmful.
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Eutrophication is the “excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen�. The main issue with eutrophication is that it heavily affects many, large bodies of water, including Lake Winnipeg. Excessive amounts of turquoise algae bloom is caused by extremely high levels of phosphate and nitrogen caused by surface runoff. Many fish rely on a healthy amount of algae to feed off of, but excessive amounts of algae has terminated many freshwater ecosystems, killing of various species of fish and endangering many more. Fishermen are unable to fish during conditions where the algae have become too thick.
Eutrophication and it's horrifying affect on biodiversity The impact of Eutrophication in marine ecosystems is steadily killing off various species of aquatic life. Common species of fish (such as the Blue Tilapia and the Suckermouth Catfish) are dying off due to the increased amounts of algae, and the effects of oxygen depletion caused by decomposing algae. In lakes which are affected heavily by eutrophication, the algae and the plant life eventually dies off, settles to the bottom of the lake, and decomposes. When aquatic plant life die, the oxygen is pulled from the body of 31
water, and is then used in the decaying process of the dead species. During decomposition, the organisms that break down the plants, use up all of the remaining oxygen left at the bottom of the lake.
“When dissolved oxygen levels decline to hypoxic levels, fish and other marine animals suffocate. As a result, creatures such as fish, shrimp, and especially immobile bottom dwellers die off.” Certain species of fish are killed due to the oxygen depletion, and this heavily affects the bodies of water’s biodiversity. Many species of fish often relocate and travel far to other large bodies of water. This can affect the new and old bodies of water because these new species of fish have become invasive species. If some of these 32
invasive species were strong, and predatory, the new body of water would suffer because many of the fish would die as sources of food for the new fish. This would result in new fish developing in the new lake, and would also decrease some of the species of fish that had already made mad that body of water their territory. Eutrophication is always tied back down to how it affects evolution. The evolution of these fish would be put to a halt because the harsh algae conditions will be killing off the fish, which makes their breeding capabilities minuscule.
Particulate matter: Air pollutants can be in the form of particulate matter which can be very harmful to our health. The level of effect usually depends on the length of time of exposure, as well the kind and concentration of chemicals and particles exposed to. Short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Others include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly.
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How Well Do You Understand Air Pollution? Another pollutant associated with climate change is sulfur dioxide, a component of smog. Sulfur dioxide and closely related chemicals are known primarily as a cause of acid rain. But they also reflect light when released in the atmosphere, which keeps sunlight out and causes Earth to cool. Volcanic eruptions can spew massive amounts of sulfur dioxide into the atmosphere, sometimes causing cooling that lasts for years. In fact, volcanoes used to be the main source of atmospheric sulfur dioxide; today people are.
WHAT CAN BE DONE? Industrialized countries have worked to reduce levels of sulfur dioxide, smog, and smoke in order to improve people's health. But a result, not predicted until recently, is that the lower sulfur dioxide levels may actually make global warming worse. Just as sulfur dioxide from volcanoes can cool the planet by blocking sunlight, cutting the amount of the compound in the atmosphere lets more sunlight through, warming the Earth. This effect is exaggerated when elevated levels of other greenhouse gases in the atmosphere trap the additional heat.
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Most people agree that to curb global warming, a variety of measures need to be taken. On a personal level, driving and flying less, recycling, and conservation reduces a person’s "carbon footprint"—the amount of carbon dioxide a person is responsible for putting into the atmosphere. On a larger scale, governments are taking measures to limit emissions of carbon dioxide and other greenhouse gases. The Paris Agreement, a voluntary agreement among 118 nations ratified on November 4, 2016, is one effort being enacted on a global scale to combat climate change. As a part of the agreement, each country agreed to take measures to combat climate change, with the ultimate goal of keeping the post-industrial global temperature rise below two degrees Celcius. Another method is to put taxes on carbon emissions or higher taxes on gasoline, so that individuals and companies will have greater incentives to conserve energy and pollute less.
AIR
POLLUTION
PREVENTION,
MONITORING
AND
SOLUTION Solution efforts on pollution is always a big problem. This is why prevention interventions are always a better way of controlling air pollution. These prevention methods can either come from government (laws) or by individual actions. In many big cities, monitoring equipment has been installed at many points in the city. Authorities read them regularly to check the quality of air. Let's see more below:
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Government (or community) level prevention Governments throughout the world have already taken action against air pollution by introducing green energy. Some governments are investing in wind energy and solar energy, as well as other renewable energy, to
minimize
burning
of
fossil
fuels,
which
cause
heavy
air
pollution.
Governments are also forcing companies to be more responsible with their manufacturing activities, so that even
though
they
still
cause
pollution,
they
are
a
lot
controlled.
Car manufacturing companies are also building more energy efficient cars, which pollute less than before.
Individual Level Prevention Encourage your family to use the bus, train or bike when commuting. If we all do this, there will be fewer cars on the road and less fumes produced.
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Use energy (light, water, boiler, kettle and fire woods) wisely. This is because lots of fossil fuels are burned to generate electricity, and so if we can cut down the use, we will also cut down the amount of pollution we create.
Recycle and re-use things. This will minimize the dependence of producing new things. Remember manufacturing industries create a lot of pollution, so if we can re-use things like shopping plastic bags, clothing, paper and bottles, it can help.
Monitoring air quality Many cities in the world, have invested in air quality monitoring systems that continuously measure the amount of pollutants in the air, as well as the safety of air in a given area.
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These monitoring systems and stations may use automatic instruments or manual means. It basically involves drawing air through various tubes with analyzers attached, all connected to a data center, where the readings are logged. In an event of rising air pollutants, signals are sent to experts. The experts examine and analyse the data and action is taken by the appropriate authorities to control the situation.
How to Help Reduce Air Pollution “The less gasoline we burn, the better we’re doing to reduce air pollution and harmful effects of climate change,”. “Make good choices about transportation. When you can, walk, ride a bike, or take public
transportation. For driving, choose cars that get better miles per gallon of gas or choose an electric car.” You can also investigate your power provider options—you may be able to request that your electricity be supplied by wind or solar. Buying your food locally cuts down on the fossil fuels burned in trucking or flying food in from across the country. And perhaps most important, “Support leaders who push for clean air and water and responsible steps on climate change,”.
How to Protect Your Health
“When you see in the newspaper or hear on
the weather report that pollution levels are high, it may be useful to limit the time when children go outside or 38
you go for a jog,”. Generally, ozone levels tend to be lower in the morning.
When you do exercise outside, stay as far as you can from heavily trafficked roads. Then shower and wash your clothes to remove fine particles.
If the air quality is bad, stay inside with windows closed.
Wear sunscreen. When ultraviolet radiation comes through the weakened ozone layer, it can cause skin damage and skin cancer.
Indoor Air Pollution
‘Indoor air’ is air within a building such as your home, classroom, office, shopping center, hospital or gym. We say ‘Indoor Air Pollution’ if indoor air is contaminated by smoke, chemicals, smells or particles. Unlike outdoor air pollution, the effect of indoor air pollution is health related and less of an environmental issue. In colder regions, building and heating methods make use of airtight spaces, less ventilation and energy efficient heating. Sometimes synthetic building materials, smells from household care and furnishing chemicals can all be trapped indoors. As less fresh air gets indoors, the concentration of pollutants such as pollen, tobacco smoke, mold, pesticides, radon, asbestos and carbon monoxide trapped inside the building increases and people breathe that in.
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Did you know: Around 3 billion people cook and heat their homes using open fires and leaky stoves, and burning biomass (wood, animal dung and crop waste) and coal. Nearly 2 million people die prematurely from illness attributable to indoor air pollution from household solid fuel use. Nearly 50% of pneumonia deaths among children under five are due to particulate matter inhaled from indoor air pollution. More than 1 million people a year die from chronic obstructive respiratory disease (COPD) that develop due to exposure to such indoor air pollution.
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Common indoor air pollutants include: Tobacco smoke: This is smoke burning cigarettes or exhaled smoke by people smoking. Biological Pollutants: These include allergens such as pollen from plants, hair from pets, fungi and some bacteria. Radon: This is a gas that is naturally emitted from the ground. Radon can be trapped in basements of building and homes. The gas is known to cause cancer after exposure over a period. Carbon Monoxide: This is a poisonous gas with no color or smell. Carbon monoxide is produced when fuels such as gas, oil, coal or wood do not burn fully.
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WATER POLLUTION What is water pollution? Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater), very often by human activities. Water pollution occur when pollutants (particles, chemicals or substances that make water contaminated) are discharged directly or indirectly into water bodies without enough treatment to get rid of harmful compounds. Pollutants get into water mainly by human causes or human factors. Water pollution
can
be
a Point-source,
Non
Point-source,
or
Transboundary in
nature.
Water pollution is the second most imperative environmental concern along with air pollution.
Any change or modification in the physical, chemical and biological properties of water that will have a detrimental consequence on living things, is water pollution. The water pollution problem Water covers over 70% of the Earth’s surface. It is a very important resource for people and the environment.
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Water pollution affects drinking water, rivers, lakes and oceans all over the world. In many developing countries, it is usually a leading cause of death, by people drinking from polluted water sources. More to this, water pollution affects not only individual living species but also populations and entire functioning ecosystems that exist in the waters. Humans have now realised the importance of clean water as a foundation for life. In recent time, more and more organisations and councils are working hard to educate, protect, restore waterways and encourage practices that help keep waters from contamination, and also to preserve water ecosystems from destruction.
TYPES OF WATER POLLUTION There are many types of water pollution because water comes from many sources. Here are a few types of water pollution:
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1. Nutrients Pollution Some wastewater, fertilizers and sewage contain high levels of nutrients. If they end up in water bodies, they encourage algae and weed growth in the water. This will make the water undrinkable, and even clog filters. Too much algae will also use up all the oxygen in the water, and other water organisms in the water will die out of oxygen starvation.
2. Surface water pollution Surface water includes natural water found on the earth's surface, like rivers, lakes, lagoons and oceans. Hazardous substances coming into contact with this surface water, dissolving or mixing physically with the water can be called surface water pollution.
3. Oxygen Depleting Water bodies have micro-organisms. These include aerobic and anaerobic organisms. When too much biodegradable matter (things that easily decay) end up in water, it encourages more microorganism growth, and they use up more oxygen in the water. If oxygen is depleted, aerobic organisms die, and
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anaerobic organisms grow more to produce harmful toxins such as ammonia and sulfides.
4. Ground water pollution When humans apply pesticides and chemicals to soils, they are washed deep into the ground by rainwater. This gets
to
underground
water,
causing
pollution
underground. This means when we dig wells and bore holes to get water from underground, it needs to be checked for ground water pollution.
5. Microbiological In many communities in the world, people drink untreated water (straight from a river or stream). Sometimes there is natural pollution caused by microorganisms like viruses, bacteria and protozoa. This natural pollution can cause fishes and other water life to die. They can also cause serious illness to humans who drink from such waters.
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6. Suspended Matter Some pollutants (substances, particles and chemicals) do not easily dissolve in water. This kind of material is called particulate matter. Some suspended pollutants later settle under the water body. This can harm and even kill aquatic organisms that live at the bottom of water bodies.
7. Chemical Water Pollution Many industries and farmers work with chemicals that end up in water. These include chemicals that are used to control weeds, insects and pests.
Metals
and
solvents
from
industries can pollute water bodies. These are poisonous to many forms of aquatic life and may slow their development, make them infertile and kill them.
8. Oil Spillage Oil spills usually have only a localized effect on wildlife but can spread for miles. The oil can cause the death to many fish and get stuck to the feathers of seabirds causing them to lose their ability to fly. Over 1,000 animals (birds, turtles, mammals) were reported dead, including many already on the endangered species list. Of the animals affected by the spill, only about 6% have been reported cleaned, but many biologists and other scientists predict they will die too from the stress caused by the pollution.
Other causes of water pollution Apart from the industrial causes of water pollution, as we saw on the previous page, here are some more:
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Sewage and waste water Every day, we cook, do laundry, flush the toilet, wash our cars, shower and do many things that use water. Think about how we use water in schools, hospitals and public places. Where do you think all the water, liquid waste, poop and urine end up? In many developed
communities, wastewater and
soluble waste (called sewage) is treated, cleaned and dumped into the sea or river. Even though they are treated, they are never the same as fresh water. In some not-so-developed countries, the sewage is not treated but quickly dumped into the sea or water bodies. This is VERY dangerous because they contaminate the environment and water bodies and bring many deadly diseases to us.
Septic Tanks Every domestic (home) toilet is connected to septic tank usually located outside the house. Each time poop is flushed down the toilet, it goes into this tank, where the solid part is separated from the liquid part. Biological processes are used to break down the solids and the liquid is usually drained out into a land drainage system. From this stage, it can escape into the
soil
and
Ocean
nearby
and
water
bodies.
marine
dumping Again, think of the rubbish we all make each day. Paper waste, food waste, plastic, rubber, metallic and aluminum waste. In some countries, they are deposited into the sea. These waste types take some time to 47
decompose. For example, it is known that paper takes about 6 weeks, aluminum takes about 200 years and glass takes even more years. When these end up in the sea, they harm sea animals and cause a lot of water animal deaths.
Underground storage and tube leakages Many liquid products (petroleum products) are stored in metal and steel tubes underground. Other sewage systems run in underground tubes. Over time, they rust and begin to leak. If that happens, they contaminate the soils, and the liquids in them end up in many nearby water bodies.
Atmospheric Atmospheric deposition is the pollution of water bodies caused by air pollution. Each time the air is polluted with sulphur dioxide and nitrogen oxide, they mix with water particles in the air and form a toxic substance. This falls as acid rain to the ground and gets washed into water bodies. The result is that water bodies also get contaminated and this affects animals and water organisms.
EFFECTS OF WATER POLLUTION You will notice in the previous pages that water pollution is very harmful to humans, animals and water life. The effects can be catastrophic, depending on the kind of chemicals, concentrations of the pollutants and where there are polluted. Below, we shall see a summary of the effects of water pollution.
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The effects of water pollution are varied and depend on what chemicals are dumped and in which locations. Many water bodies near urban areas (cities and towns) are highly polluted. This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by manufacturing industries, health centers, schools and market places.
Death of aquatic (water) animals The main problem caused by water pollution is that it kills organisms that depend on these water bodies. Dead fish, crabs, birds and sea gulls, dolphins, and many other animals often wind up on beaches, killed by pollutants in their habitat (living environment).
Disruption of food-chains Pollution disrupts the natural food chain as well. Pollutants such as lead and cadmium are eaten by tiny animals. Later, these animals are consumed by fish and shellfish, and the food chain continues to be disrupted at all higher levels.
Diseases Eventually, humans are affected by this process as well. People can get diseases such as hepatitis by eating seafood that has been poisoned. In many poor nations, there is always outbreak of cholera and diseases as a result of poor drinking water treatment from contaminated waters.
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Destruction of ecosystems Ecosystems (the interaction of living things in a place, depending on each other for life) can be severely changed or destroyed by water pollution. Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans in many ways.
Human Health We all drink water that comes from a source: this may be a lake or local river. In countries that have poor screening and purification practices, people often get water-borne disease outbreaks such as cholera and tuberculosis. Every year, there are an estimated 3–5 million cholera cases and 100,000–120,000 deaths due
to
cholera.
(WHO
estimates
that
only
5–10%
of
cases
are
officially
reported.)
In developed countries, even where there are better purification methods, people still suffer from the health effects of water pollution. Take toxins emitted by algae growth for instance: this can cause stomach 50
aches and rashes. Excess nitrogen in drinking water also pose serious risks to infants. EPA’s 2010 National Lakes Assessment found that almost 20 percent of the nation’s lakes have high levels of nitrogen and phosphorus pollution. The report also showed that poor lake conditions related to nitrogen
or
phosphorus
pollution
doubled
the
likelihood
of
poor
ecosystem
health.
Ecosystems
Nutrient pollution from upstream (creeks and streams) often flow downhill and even travel miles into other larger water bodies. The effect is that, it breeds algae growth and causes the growth of many more water organism. This algae attack affects fish and other aquatic animals by absorbing and reducing their oxygen supply. Algae growth also clogs fish gills. Naturally, the order of ecosystems in that water are affected negatively, as the destruction or introduction of any foreign organism alter the entire food chain in there.
3. Death of animals Animals, including water animals die when water is poisoned for various reasons. Other animals are stressed and their 51
populations are endangered. In a classic case of marine pollution in recent time, 16000 miles of a US coastline was affected by an oil spill. That water pollution caused a lot of damage and deaths of many animals. Over 8,000 animals (birds, turtles, mammals) were reported dead just 6 months after the spill, including many that are already on the endangered species list. Immediate impact on the wildlife includes oil-coated birds and sea turtles, mammal ingestion of oil, and dead or dying deep sea coral2. Animals are also affected by solid waste thrown into water bodies, as they harm them in many ways.
4. Economic cost From the above it is evident that there is some real financial implications that will result from water pollution. It can cost a lot more to purify drinking water that takes its source from nutrient polluted water bodies. Fishing stock is affected negatively when there is a depletion of oxygen. Consumers are also weary of fish from these sources and tend to stay away from them, costing fisheries to lose revenue. In places where there are water activities or sports, lots of money is spent to clean up the water from algae blooms and the like.
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SOIL POLLUTION With the rise of concrete buildings and roads, one part of the Earth that we rarely see is the soil. It has many different names, such as dirt, mud and ground. However, it is definitely very important to us. The plants that feed us grow in soil and keeping it healthy is essential to maintaining a beautiful planet. However, like all other forms of nature, soil also suffers from pollution. The pollution of soil is a common thing these days, and it happens due to the presence of man made elements.
The main reason why the soil becomes contaminated is due to the presence of man made waste. The waste produced from nature itself such as dead plants, carcasses of animals and rotten fruits and vegetables only adds to the fertility of the soil. However, our waste products are full of chemicals that are not originally found in nature and lead to soil pollution.
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Soil Pollution Soil pollution occurs when the presence of toxic chemicals, pollutants or contaminants in the soil is in high enough concentrations to be of risk to plants, wildlife, humans and of course, the soil itself. Arable land is turning to desert and becoming non-arable at ever-increasing rates, due largely in part to global warming and agricultural fertilizers and pesticides, lessening the hope that we can feed our booming population. years, there will be over 2 billion more people, which is the equivalent of adding another China and India. Food production will have to increase at least 40% and most of that will have to be grown on the fertile soils that cover just 11% of the global land surface. However, there is little new land that can be brought into production and existing land is being lost and degraded. The United Nations Food and Agricultural Organization states that annually, 75 billion tons of soil, the equivalent of nearly 10 million hectares, which is about 25 million acres, of arable land is lost to erosion, water-logging and salination and another 20 million hectares is abandoned because its soil quality has been degraded. Contact with contaminated soil may be direct, from using parks, schools etc., or indirect by inhaling soil contaminants which have vaporized or through the consumption of plants or animals that have accumulated large amounts of soil pollutants, and may also result from secondary contamination of water supplies and from deposition of air contaminants.
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Main Causes of Soil Pollution Soil Pollution Causes and Effects That are Seriously Eye-opening. Along with air and water pollution, soil pollution is an equally serious issue that the modern-day world is confronted with. The conquest of utilizing land and soil resources and conducting experiments on it for our benefits is one major reason for soil pollution.
What Causes Soil Pollution?
Industrial wastes such as harmful gases and chemicals, agricultural pesticides, fertilizers and insecticides are the most common causes of soil pollution.
Ignorance towards soil management and related systems.
Unfavorable and harmful irrigation practices.
Improper septic system and management and maintenance of the same.
Leakages from sanitary sewage.
Acid rain, when fumes released from industries mix with rain.
Fuel leakage from automobiles that get washed away due to rain and seep into nearby soil.
Unhealthy waste management techniques, which are characterized by release of sewage into the large dumping grounds and nearby streams or rivers.
The intensity of all causes on a local or regional level might appear very small and you may argue that soil is not harmed by above activities if done on a small scale! However, thinking globally, it is not your region or my place that will be the only sufferer of soil pollution. In fact, it is the entire planet and mankind that will encounter serious problems, as these practices are evident almost everywhere in the 55
world.
1. Industrial Activity: Industrial activity has been the biggest contributor to the problem in the last century, especially since the amount of mining and manufacturing has increased. Most industries are dependent on extracting minerals from the Earth. Whether it is iron ore or coal, the by products are contaminated and they are not disposed off in a manner that can be considered safe. As a result, the industrial waste lingers in the soil surface for a long time and makes it unsuitable for use.
2. Agricultural Activities:
Chemical utilization has gone up tremendously since technology
provided us with modern pesticides and fertilizers. They are full of chemicals that are not produced in nature and cannot be broken down by it. As a result, they seep into the ground after they mix with water and slowly reduce the fertility of the soil. Other chemicals damage the composition of the soil and make it easier to erode by water and air. Plants absorb many of these pesticides and when they decompose, they cause soil pollution since they become a part of the land. 56
3. Waste Disposal: Finally, a growing cause for concern is how we dispose of our waste. While industrial waste is sure to cause contamination, there is another way in which we are adding to the pollution. Every human produces a certain amount of personal waste products by way or urine and feces. While much of it moves into the sewer the system, there is also a large amount that is dumped directly into landfills in the form of diapers. Even the sewer system ends at the landfill, where the biological waste pollutes the soil and water. This is because our bodies are full of toxins and chemicals which are now seeping into the land and causing pollution of soil.
4. Accidental Oil Spills: Oil
leaks can happen during storage and transport of
chemicals. This can be seen at most of the fuel stations. The chemicals present in the fuel deteriorates the quality of soil and make them unsuitable for cultivation. These chemicals can enter into the groundwater through soil and make the water undrinkable.
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5. Acid Rain: Acid rain is caused when pollutants present in the air mixes up with the rain and fall back on the ground. The polluted water could dissolve away some of the important nutrients found in soil and change the structure of the soil.
Effects of Soil Pollution Soil pollution can have a number of harmful effects on ecosystems and human, plants and animal health. The harmful effects of soil pollution may come from direct contact with polluted soil or from contact with other resources, such as water or food which has been grown on or come in direct contact with the polluted soil.
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1. Effect on Health of Humans: Considering how soil is the reason we are able to sustain ourselves, the contamination of it has major consequences on our health. Crops and plants grown on polluted soil absorb much of the pollution and then pass these on to us. This could explain the sudden surge in small and terminal illnesses.
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Long term exposure to such soil can affect the genetic make-up of the body, causing congenital illnesses and chronic health problems that cannot be cured easily. In fact, it can sicken the livestock to a considerable extent and cause food poisoning over a long period of time. The soil pollution can even lead to widespread famines if the plants are unable to grow in it.
The Effects of Soil Pollution on Humans Soil pollution occurs when soil contains chemicals that are toxic or otherwise dangerous for humans and other living things. The chemicals may be foreign to the area, or they may be naturally occurring materials that pollute the soil by being present in dangerously high amounts. Soil pollution can have a number of harmful effects on human health.
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The harmful effects of soil pollution may come from direct contact with polluted soil or from contact with other resources, such as water, that have come in direct contact with the polluted soil.
Organ Damage The presence of heavy metals in soil in toxic amounts can cause irreversible developmental damage in children, according to the website Tropical Rainforest Animals. Although lead and mercury may be found naturally in soil, high concentrations of either metal may cause damage to the developing brains of young children, which in turn may lead to neurological problems. Humans of any age may also suffer kidney or liver damage from exposure to excessive mercury in soil.
Bioaccumulation Soil that is not significantly polluted may still harm humans indirectly, according to Pollution Issues. One way such soil pollution can harm humans is by bioaccumulation. Plants that are grown in lightly polluted soil continuously absorb molecules of the pollutants. Since the plants cannot get rid of these molecules, they accumulate in the plant, causing higher amounts of 61
pollution to exist in the plant than in the soil. Animals who eat many of these polluted plants take on all the pollution those plants have accumulated. Larger animals who eat the plant-eating animals take on all the pollution from the animals they eat. Humans who eat plants or animals that have accumulated large amounts of soil pollutants may be poisoned, even if the soil itself does not contain enough pollution to harm human health.
Cancer Many common soil pollutants are carcinogenic, or cancer-causing. According to the U.S. Environmental Protection Agency, humans who are exposed to these pollutants are far more likely to develop cancer than humans who are not exposed to them. For example, regular exposure to benzene is known to cause leukemia in both children and adults. Exposure to polychlorinated biphenyls (PCBs) is linked to liver cancer.
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Economic Losses In addition to endangering human health, soil pollution can also cause economic damage. For example, in some parts of China, soil that is polluted with heavy metals is nevertheless used to grow grain. The grain grown in these soils is often polluted with heavy metals. According to China Dialogue, an estimated 12 million tons of polluted grain must be disposed of each year, costing Chinese farmers up to 20 billion yuan, or about $2.57 billion U.S.
Animals Soil
pollution
can
negatively
affect
the
metabolism
of
microorganisms and arthropods, which can destroy some layers of the primary food chain and have a harmful effect on predator animal species. Also, small life forms may consume harmful chemicals in the soil which may then be passed up the food chain to larger animals, which may lead to increased mortality rates and even animal extinction.
2. Effect on Growth of Plants: The ecological balance of any system gets affected due to the widespread contamination of the soil. Most plants are unable to adapt when the chemistry of the soil changes so radically in a short period of time. Fungi and bacteria found in the soil that bind it together begin to decline, which creates an additional problem of soil erosion. The fertility slowly diminishes, making land unsuitable for agriculture and any local vegetation to survive. The soil pollution causes large tracts of land to become hazardous to health. Unlike deserts, which are suitable for its native vegetation, such land cannot support most forms of life.
3. Decreased Soil Fertility: The toxic chemicals present in the soil can decrease soil fertility and therefore decrease in the soil yield. The contaminated soil is then used to produce fruits and
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vegetables which lacks quality nutrients and may contain some poisonous substance to cause serious health problems in people consuming them.
4. Toxic Dust: The emission of toxic and foul gases from landfills pollutes the environment and causes serious effects on health of some people. The unpleasant smell causes inconvenience to other people.
5. Changes in Soil Structure: The death of many soil organisms (e.g. earthworms) in the soil can lead to alteration in soil structure. Apart from that, it could also force other predators to move to other places in search of food. A number of ways have been suggested to curb the current rate of pollution. Such attempts at cleaning up the environment require plenty of time and resources to be pitched in. Industries have been given regulations for the disposal of hazardous waste, which aims at minimizing the area that becomes polluted. Organic methods of farming are being supported, which do not use chemical laden pesticides and fertilizers. Use of plants that can remove the pollutants from the soil is being encouraged. However, the road ahead is quite long and the prevention of soil pollution will take many more years.
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What are the Effects of Soil Pollution?
Loss of soil and natural nutrients present in it. Plants also would not thrive in such soil, which would further result in soil erosion.
Disturbance in the balance of flora and fauna residing in the soil.
Increase in salinity of the soil, which therefore makes it unfit for vegetation, thus making it useless and barren.
Generally crops cannot grow and flourish in polluted soil. Yet, if some crops manage to grow, they would be poisonous enough to cause serious health problems in people consuming them.
Creation of toxic dust is another potential effect of soil pollution.
Foul smell due to industrial chemicals and gases might result in headaches, fatigue, nausea, etc., in many people.
Soil pollutants would bring in alteration in the soil structure, which would lead to death of many essential organisms in it. This would also affect the larger predators and compel them to move to other places, once they lose their food supply.
I hope the above discussion was enough to make you understand the severity of the soil pollution causes and effects. Soil pollution can be cured by transporting the contaminated soil layer to some remote place, thus making it once again fit for use. Harmful chemicals from the soil can also be removed by aerating it. These are just 'tentative solutions'. However, let us remember the proverb, 'prevention is better than cure', and follow proper a soil management system, maintain sewage systems, and avoid the overuse of fertilizers and pesticides in the soil. So let us begin the movement of soil pollution prevention from our own lands itself!!!
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NOISE POLLUTION Sound is essential to our daily lives, but noise is not. Noise is generally used as an unwanted sound, or sound which produces unpleasant effects and discomfort on the ears.
Sound becomes unwanted when it either interferes with normal activities such as sleeping, conversation, or disrupts or diminishes one’s quality of life. Not all noise can be called noise pollution. If it does not happen reqularly, it may be termed as 'Nuisance'.
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Scientists also believe that its not only humans who are affected. For example, water animals are subjected to noise by submarines and big ships on the ocean, and chain-saw operations by timber companies also create extreme noise to animals in the forests. Generally, noise is produced by household gadgets, big trucks, vehicles and motorbikes on the road, jet planes and helicopters hovering over cites, loud speakers etc. Noise (or sound) is measured in the units of decibels and is denoted by the dB. Noise which is more than 115 dB is tolerant. The industrial limit of sound in the industries must be 75 dB according to the World Health Organization.
Noise is considered as environmental pollution, even though it is thought to have less damage on humans than water, air or land pollution. But people who are affected by severe noise pollution know that it is a massive issue that needs attention. Most of us are very used to the sounds we hear in everyday life. Loud music, the television, people talking on their phone, the traffic and even pets barking in the middle of the night. All of these have become a part of the urban culture and rarely disturb us. However, when the sound of the television keeps you from sleeping all night or the traffic starts to give you a headache, it stops becoming just noise and start turning into noise pollution. For many of us, the concept of pollution is limited to nature and resources. However, noise that tends to disrupt the natural rhythm of life makes for one solid pollutant. 67
By definition, noise pollution takes place when there is either excessive amount of noise or an unpleasant sound that causes temporary disruption in the natural balance. This definition is usually applicable to sounds or noises that are unnatural in either their volume or their production. Our environment is such that it has become difficult to escape noise. Even electrical appliances at home have a constant hum or beeping sound. By and large, lack of urban planning increases the exposure to unwanted sounds. This is why understanding noise pollution is necessary to curb it in time.
What are the sources of noise pollution?
Noise can come from many places. Let us see a few good sources:
1. Industrialization: Most of the industries use big machines which are capable of producing large amount of noise. Apart from that, various equipments like compressors, generators, exhaust fans, grinding mills also participate in producing big noise. Therefore, you must have seen workers in these factories and industries wearing ear plugs to minimize the effect of noise.
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2. Poor Urban Planning: In most of the developing countries, poor urban planning also play a vital role. Congested houses, large families sharing small space, fight over parking, frequent fights over basic amenities leads to noise pollution which may disrupt the environment of society.
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3. Social Events: Noise is at its peak in most of the social events. Whether it is marriage, parties, pub, disc or place of worship, people normally flout rules set by the local administration and create nuisance in the area. People play songs on full volume and dance till midnight which makes the condition of people living nearby pretty worse. In markets, you can see people selling clothes via making loud noise to attract the attention of people. Places of worship, discos and gigs, parties and other social events also create a lot of noise for the people living in that area. In many market areas, people sell with loud speakers, others shout out offers and try to get customers to buy their goods. It is important to note that whey these events are not often, they can be called 'Nuisance' rather than noise pollution.
4. Transportation: Large number of vehicles on roads, aeroplanes flying over houses, underground trains produce heavy noise and people get it difficult to get accustomed to that. The high noise leads to a situation wherein a normal person lose the ability to hear properly.
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5. Construction Activities: Under construction activities like mining, construction of bridges, dams, buildings, stations, roads, flyovers take place in almost every part of the world. These construction activities take place everyday as we need more buildings, bridges to accommodate more people and to reduce traffic congestion. The down point is that these construction equipments are too noisy.
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6. Commercial and industrial activities: Printing presses, manufacturing industries, construction sites, contribute to noise pollutions in large cities. In many industries, it is a requirement that people always wear earplugs to minimize their exposure to heavy noise. People who work with lawn mowers, tractors and noisy equipment are also required to wear noise-proof gadgets.
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7. Household Chores: We people are surrounded by gadgets and use them extensively in our daily life. Gadgets like TV, mobile , mixer grinder, pressure cooker, vacuum cleaners , washing machine and dryer, cooler, air conditioners are minor contributors to the amount of noise that is produced but it affects the quality of life of your neighborhood in a bad way.
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Others include loud speakers of sound systems and TVs, ipods and ear phones. Another example may be your neighbor’s dog barking all night everyday at every shadow it sees, disturbing everyone else in the apartment.
While this form of pollution may seem harmless, it in fact has far reaching consequences. The adverse effects on the health of the environment are quite severe. Not only is the local wildlife affected by the pollution, humans also face a number of problems due to it.
What can be called a 'Nuisance'? Nuisance is usually used to describe an activity or condition that is harmful or annoying to others (e.g., indecent conduct, a rubbish heap or lot of birds making their nests in someones roof to the extent that they cause problems)
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A few good examples of nuisance include: Barking dogs Building and construction site noise (please note however that noisy 8am and 6pm Monday to Friday, and 8am to 1pm on Saturdays) DIY noise during anti-social hours Burglar / car alarms Noisy deliveries at unreasonable hours Parties, Nightclubs and pubs Loud music / television / computer games Industrial processes (dry cleaners, factories etc) Kitchen extract / air conditioning units Places of worship Open-air event and street performers.
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Work is permitted between
A public nuisance is an unreasonable interference with the public's right to property. It includes conduct that interferes with public health, safety, peace or convenience. This is a term that is mostly used in law and court rooms. Statutory Nuisance can also be used for instances including the adverse effects of artificial light, dust, odour and insects. Generally, all the above can mean different things to different people. For example, if your neighbor is a lover of cats, and you are not, it will not be long before you have problems if the cats keep coming to your balcony. Another cat lover may find this exciting and will be very happy with that. So you see, usually, the term 'Nuisance' is used in relation to the average or generally acceptable conditions of a place or group of people.
Effects of noise pollution Generally, problems caused by noise pollution include stress related illnesses, speech interference, hearing loss, sleep disruption, and lost productivity. Most importantly, there are three major effects we can look at:
1. Hearing Problems: Any unwanted sound that our ears have not been built to filter can cause problems within the body. Our ears can take in a certain range of sounds without getting damaged. Man made noises such as jackhammers, horns, machinery, airplanes and even vehicles can be too loud for our hearing range. Constant exposure to loud levels of noise can easily result in the damage of our ear drums and loss of hearing. It also reduces our sensitivity to sounds that our ears pick up unconsciously to regulate our body’s rhythm.
2. Health Issues: Excessive noise pollution in working areas such as offices, construction sites, bars and even in our homes can influence psychological health. Studies show that the occurrence of aggressive behavior, disturbance of sleep, constant stress, fatigue and hypertension can be linked to excessive noise levels. These in turn can cause more severe and chronic health issues later in life. 76
Effects on general health Health effects of noise include anxiety and stress reaction and in extreme cases fright. The physiological manifestations are headaches, irritability and nervousness, feeling of fatigue and decreases work efficiency. For example, being pounded by the siren of fire fighters, police or ambulance in your city all night everyday leave people (especially elderly people) stresses and tired in the morning.
Hearing loss A sound level meter, a basic tool in measuring sound.
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The mechanism of hearing loss can be attributed to aging, infection, surgery, prolonged use of some medications, trauma, and to stereocilia of the cochlea, the principal fluid filled structure of the inner ear. The pinna combined with the middle ear amplifies sound pressure levels by a factor of twenty, so that extremely high sound pressure levels arrive in the cochlea, even from moderate atmospheric sound stimuli. Underlying pathology to the cochlea are reactive oxygen species, which play a significant role in noise-induced necrosis and apoptosis of the stereocilia.
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Exposure to high levels of noise have differing effects within a given population, and the involvement of reactive oxygen species suggests possible avenues to treat or prevent damage to hearing and related cellular structures. The elevated sound levels cause trauma to cochlear structure in the inner ear, which gives rise to irreversible hearing loss. A very loud sound in a particular frequency range can damage the cochlea's hair cells that respond to that range, thereby reducing the ear's ability to hear those frequencies in the future, however, loud noise in any
frequency
range
has
deleterious effects across the entire range of human hearing. The outer ear (visible portion of the human ear) combined with the middle ear amplifies sound levels by a factor of 20 when sound reaches the inner ear.
Age-related (presbycusis) Hearing loss is somewhat inevitable with age. Though older males exposed to significant occupational noise demonstrate significantly reduced hearing sensitivity compared to non-exposed peers. Differences in hearing sensitivity decrease with time and the two groups are indistinguishable by age 79.Over time, the detection of high-pitched sound frequencies becomes more difficult. This affects speech perception, particularly of those words involving sibilants and fricatives. Both ears tend to be affected. Women exposed to occupational noise do not differ from their peers in hearing sensitivity, although they do hear better than their non-exposed male counterparts. Consistent exposure to loud music, young people in the United States have a rate of impaired hearing 2.5 times greater than their parents and grandparents. An estimated 50 million individuals will have in 2050.
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Occupational hearing loss
Hearing loss as a result of occupational exposure is one of the most common work-related illnesses. In fact, every year in the United States, more than 22 million workers are exposed to hazardous noise and an additional 9 million are exposed to ototoxic chemicals.[18] Those in certain occupations are at a higher risk of developing hearing loss as a result of the nature of their job. For example, musicians,[19] miners,and those in manufacturing and construction may be exposed to higher and more constant noise levels. Any workplace that exposes workers to excessive sound levels is required to ensure that the hearing function of their workers is adequately protected. The Occupational Safety and Health Administration
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(OSHA) provide laws and regulations clarified by the United States department of labor. Generated by the Occupational Safety and Health Act of 1970, OSHA was created with the mission to assure all working conditions are safe and healthy. All employers must follow this hearing amendment, including private sector employers, and excluding those who are self-employed, family farm workers, and government workers. Separate laws and regulations are enacted for specialized working environments.
Cardiovascular effects Noise has been associated with important cardiovascular health problems.In 1999, the World Health Organization (WHO) concluded that the available evidence suggested a weak correlation between longterm noise exposure above 67-70 dB(A) and hypertension. More recent studies have suggested that noise levels of 50 dB(A) at night may also increase the risk of myocardial infarction by chronically elevating cortisol production.
Fairly typical roadway noise levels are sufficient to constrict arterial blood flow and lead to elevated blood pressure; in this case, it appears that a certain fraction of the population is more susceptible to vasoconstriction. This may result because annoyance from the sound causes elevated adrenaline levels trigger a narrowing of the blood vessels (vasoconstriction), or independently through medical stress reactions. Other effects of high noise levels are increased frequency of headaches, fatigue, stomach ulcers, and vertigo.
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Stress Research commissioned by Rockwool, a UK insulation manufacturer, reveals in the UK one third (33%) of victims of domestic disturbances claim loud parties have left them unable to sleep or made them stressed in the last two years. Around one in eleven (9%) [29] of those affected by domestic disturbances claims it has left them continually disturbed and stressed. More than 1.8 million people claim noisy neighbours have made their life a misery and they cannot enjoy their own homes. The impact of noise on health is potentially a significant problem across the UK given that more than 17.5 million Britons (38%) have been disturbed by the inhabitants of neighbouring properties in the last two years. For almost one in ten (7%) Britons this is a regular occurrence.
Annoyance Because some stressful effects depend on qualities of the sound other than its absolute decibel value, the annoyance associated with sound may need to be considered in regard to health effects. For example, noise from airports or sudden Impulse noises are typically perceived as more bothersome than noise from traffic of equal volume. Annoyance effects of noise are minimally affected by demographics, but fear of the noise source and sensitivity to noise both strongly affect the 'annoyance' of a noise. Even sound levels as low as 40 dB(A) (about as loud as a refrigerator or library) can generate noise complaints and the lower threshold for noise producing sleep disturbance is 45 dB(A) or lower.
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Other factors that affect the 'annoyance level' of sound include beliefs about noise prevention and the importance of the noise source, and annoyance at the cause (i.e. non-noise related factors) of the noise. For instance, in an office setting, audible telephone conversations and discussions between co-workers were considered to be irritating, depending upon the contents of the conversations. Many of the interpretations of the level of annoyance and the relationship between noise levels and resulting health symptoms could be influenced by the quality of interpersonal relationships at the workplace, as well as the stress level generated by the work itself. Evidence for impact on annoyance of long-term noise versus recent changes is equivocal.
Estimates of sound annoyance typically rely on weighting filters, which consider some sound frequencies to be more important than others based on their presumed audibility to humans. The older dB(A) weighting filter described above is used widely in the U.S., but underestimates the impact of frequencies around 6000 Hz and at very low frequencies. The newer ITU-R 468 noise weighting filter is used more widely in Europe. The propagation of sound varies between environments; for example, low frequencies typically carry over longer distances. Therefore, different filters, such as dB(B) and dB(C), may be recommended for specific situations. 83
Child physical development The Environmental Protection Agency authored a pamphlet in 1978 that suggested a correlation between low-birthweight (using the World Health Organization definition of less than 2,500 grams (88 oz) and high sound levels, and also high rates of birth defects in places where expectant mothers are exposed to elevated sound levels, such as typical airport environs. Specific birth abnormalities included harelip, cleft palate, and defects in the spine.
According to Lester W. Sontag of The Fels Research Institute (as presented in the same EPA study): “There is ample evidence that environment has a role in shaping the physique, behavior, and function of animals, including man, from conception and not merely from birth. The fetus is capable of perceiving sounds and responding to them by motor activity and cardiac rate change." The effects of noise exposure are highest when it occurs between 15 and 60 days after conception, a period in which major internal organs and the central nervous system are formed. Later developmental effects occur as vasoconstriction in the mother reduces blood flow and therefore oxygen and nutrition to the fetus. Low birth weights and noise were also associated with lower levels of certain hormones in the mother. These hormones are thought to affect fetal growth and to be good indicators of protein production. The difference between the hormone levels of pregnant mothers in noisy versus quiet areas increased as birth approached.
3. Sleeping Disorders: Loud noise can certainly hamper your sleeping pattern and may lead to irritation and uncomfortable situations. Without a good night sleep, it may lead to problems related to
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fatigue and your performance may go down in office as well as at home. It is therefore recommended to take a sound sleep to give your body proper rest.
4. Trouble Communicating: High decibel noise can put trouble and may not allow two people to communicate freely. This may lead to misunderstanding and you may get difficult understanding the other person. Constant sharp noise can give you severe headache and disturb your emotional balance.
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6. Effect on Wildlife: Wildlife faces far more problems than humans because noise pollution since they are more dependent on sound. Animals develop a better sense of hearing than us since their survival depends on it. The ill effects of excessive noise begin at home. Pets react more aggressively in households where there is constant noise. They become disoriented more easily and face many behavioral problems. In nature, animals may suffer from hearing loss, which makes them easy prey and leads to dwindling populations. Others become inefficient at hunting, disturbing the balance of the eco-system.
Species that depend on mating calls to reproduce are often unable to hear these calls due to excessive man made noise. As a result, they are unable to reproduce and cause declining populations. Others require sound waves to echo-locate and find their way when migrating. Disturbing their sound signals means they get lost easily and do not migrate when they should. To cope up with the increasing sound around them, animals are becoming louder, which may further add to the pollution levels. This is why understanding noise pollution can help us lower the impact it has on the environment.
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As of now, there do not exist many solutions to reduce sound pollution. On a personal level, everybody can help reducing the noise in their homes by lowering the volume of the radio, music system and the television. Listening to music without headphones is also a good step forward. Removal of public loudspeakers is another way in which the pollution can be countered. Marine Animals Marine scientists are concerned about excessive noise used by oil drills, submarines and other vessels on and inside the ocean. Many marine animals, especially whales, use hearing to find food, communicate, defend and survive in the ocean. Excessive noises are causing a lot of injuries and deaths to whales. For example, the effect of a navy submarine’s sonar can be felt 300 miles away from the source.
(SONAR is the use of sound by submarines and other fishing vessels to deterring the depth of water, the closeness of an object, or detect movement of other objects in the water) Many of these beached whales have suffered physical trauma, including bleeding around the brain, ears and other tissues and large bubbles in their organs. 87
There is no question that sonar injures and kills whales and dolphins. – Joel Reynolds, NRDC senior attorney (http://www.nrdc.org/wildlife/marine/sonar.asp) This is not only about whales, but the larger marine life are all affected in one way or the other. Its is worth noting that these effects may not sound troubling, but the truth is, with time, the consequences can be very worrying.
Noise pollution prevention and control tips Below are a few things people and governments can do to make our communities and living laces quieter:
Construction of soundproof rooms for noisy machines in industrial and manufacturing installations must be encouraged. This is also important for residential building—noisy machines should be installed far from sleeping and living rooms, like in a basement or garage. Use of horns with jarring sounds, motorbikes with damaged exhaust pipes, noisy trucks to be banned. Noise producing industries, airports, bus and transport terminals and railway stations to sighted far from where living places. Community law enforcers should check the misuse of loudspeakers, worshipers, outdoor parties and discos, as well as public announcements systems. 88
Community laws must silence zones near schools / colleges, hospitals etc. Vegetation (trees) along roads and in residential areas is a good way to reduce noise pollution as they absorb sound.
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LIGHT POLLUTION Light pollution is excessive, misdirected, or obtrusive artificial (usually outdoor) light. Too much light pollution has consequences: it washes out starlight in the night sky, interferes with astronomical research, disrupts ecosystems, has adverse health effects and wastes energy.
Introduction A little more than 100 years ago, you could walk outside at night even in a city and see the Milky Way galaxy arch across the night sky. Being able to see thousands of stars was part of everyday life, inspiring artists like Van Gogh or musical composers like Holst or writers like Shakespeare. By allowing artificial lights to wash out our starry night skies, we are losing touch with our cultural heritage (e.g., what has made us who we are). We are also losing touch with what could inspire future generations.
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With more than half of the world’s population now living in cities, 3 out of every 4 people in cities have never experienced the wonderment of pristinely dark skies. How do you explain the importance of what they’ve lost to light pollution? Light pollution is an unwanted consequence of outdoor lighting and includes such effects as sky glow, light trespass, and glare. An illustration of both useful light and the components of light pollution are illustrated in Figure 2. Sky glow is a brightening of the sky caused by both natural and human-made factors. The key factor of sky glow that contributes to light pollution is outdoor lighting. Figure 2. Example of useful light and light pollution from a typical pole-mounted outdoor luminaire
Source: Adapted from Institution of Lighting Engineers
Light trespass is light being cast where it is not wanted or needed, such as light from a streetlight or a floodlight that illuminates a neighbor’s bedroom at night making it difficult to sleep. Glare can be thought of as objectionable brightness. It can be disabling or discomforting. There are several kinds of glare, the worst of which is disability glare, because it causes a loss of visibility from stray light being scattered within the eye. Discomfort glare is the sensation of annoyance or even pain induced by overly bright sources. Think of driving along a dark road when an oncoming car with bright headlights suddenly appears. The sudden bright light can be uncomfortable and make it difficult to see.
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Discomfort and even disability glare can also be caused by streetlights, parking lot lights, floodlights, signs, sports field lighting, and decorative and landscape lights.
What is sky glow? Sky glow occurs from both natural and human-made sources. The natural component of sky glow has five sources: sunlight reflected off the moon and earth, faint air glow in the upper atmosphere (a permanent, low-grade aurora), sunlight reflected off interplanetary dust (zodiacal light), starlight scattered in the atmosphere, and background light from faint, unresolved stars and nebulae (celestial objects or diffuse masses of interstellar dust and gas that appear as hazy smudges of light). Natural sky glow is well quantified. In this publication, further discussion of sky glow considers
only
human-made
sources. Electric lighting also increases night sky brightness and is the human-made source of sky glow. Light that is either emitted directly upward by luminaires or reflected from the ground is scattered by dust and gas molecules in the atmosphere, producing a luminous background. It has the effect of reducing one’s ability to view the stars, as seen in Figure 3. Sky glow is highly variable depending on immediate weather conditions, quantity of dust and gas in the atmosphere, amount of light directed skyward, and the direction from which it is viewed. In poor weather conditions, more particles are present in the atmosphere to scatter the upward-bound light, so sky glow becomes a very visible effect of wasted light and wasted energy. Sky glow is of most concern to astronomers because it reduces their ability to view celestial objects. Sky glow increases the brightness of the dark areas of the sky, which reduces the contrast of stars or other celestial objects against the dark sky background. Astronomers typically like very dry clear dark nights for observing. A typical suburban sky is 5 to 10 times brighter at the zenith than the natural sky (the zenith is the angle that points directly upward, or 180°, from the observation point). In city centers, the zenith may be 25 or 50 times brighter than the natural background.
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How can you make them aware that light pollution is a concern on many fronts: safety, energy conservation, cost, health and effects on wildlife, as well as our ability to view the stars? Finally, how do you convince them that it’s worthwhile to take even small steps, to help fix this problem?
Light pollution is excessive and inappropriate artificial light. The four components of light pollution are often combined and may overlap:
Urban Sky Glow—the brightening of the night sky over inhabited areas.
Light Trespass—light falling where it is not intended, wanted, or needed.
Glare—excessive brightness which causes visual discomfort. High levels of glare can decrease visibility.
Clutter—bright, confusing, and excessive groupings of light sources, commonly found in over-lit urban areas. The proliferation of clutter contributes to urban sky glow, trespass, and glare.
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For most of Earth’s history, our spectacular universe of stars and galaxies has been visible in the darkness of the night sky. From our earliest beginnings, the vast spectacle arrayed across the dark sky has inspired questions about our universe and our relation to it.
The history of scientific discovery, art, literature, astronomy, navigation, exploration, philosophy, and even human curiosity itself would be diminished without our view of the stars. But today, the increasing number of people living on earth and the corresponding increase in inappropriate and unshielded outdoor lighting has resulted in light pollution—a brightening night sky that has obliterated the stars for much of the world’s population. Most people must travel far from home, away from the glow of artificial lighting, to experience the awe-inspiring expanse of the Milky Way as our ancestors once knew it.
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The negative effects of the loss of this inspirational natural resource might seem intangible. But a growing body of evidence links the brightening night sky directly to measurable negative impacts on human health and immune function, on adverse behavioral changes in insect and animal populations, and on a decrease of both ambient quality and safety in our nighttime environment. Astronomers were among the first to record the negative impacts of wasted lighting on scientific research, but for all of us, the adverse economic and environmental impacts of wasted energy are apparent in everything from the monthly electric bill to global warming.
In refreshing contrast to some of today’s complex and lingering environmental problems, many existing solutions to light pollution are simple, cost-effective, and instantaneous. Recognizing when outdoor lighting no longer serves its function and becomes a pollutant is the first step toward choosing appropriate solutions. Increased urban sky glow is responsible for the disappearance of the Milky Way from our night skies. For professional astronomers, the increasing distance to prime observing sites, well away from sources of air pollution and urban sky glow, becomes more problematic as economic and environmental energy costs continue to rise. Amateur astronomers, meanwhile, find prime observing spots eradicated by commercial and residential development and must travel farther from home for a clear view of the skies. Increasingly,
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the most important equipment needed to enjoy the wonders of the night sky is an automobile with a full tank of gas and a map.
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What is light trespass? Light trespass occurs when spill light is cast where it is not wanted. Light trespass is somewhat subjective because it is difficult to define when, where, and how much light is unwanted. An example of light trespass is when spill light from a streetlight or floodlight enters a window and illuminates an indoor area.
Figures
4
and
5
depict
examples of light trespass. The light trespass shown in Figure 4 would be significantly reduced if a shield were placed on the luminaire. In Figure 5, the floodlight on the hotel casts light on the home across the street. Proper aiming
of
the
floodlight
and
shielding would significantly reduce the light trespass shown in this example.
The adverse effects of light pollution extend well beyond astronomy. New research suggests that light at night may interfere with normal circadian rhythms—the 24-hour cycle of day and night that humans have used to maintain health and regulate their activities for thousands of years. Light trespass, occurring 97
when streetlights or a neighbor’s security light directs unwanted lighting onto our property or into our homes, contributes to a loss of natural darkness. Wildlife, too, is harmed by the unnecessary brightening of the night. From newly hatched sea turtles to migrating birds, fish, frogs, salamanders, and lightning bugs, artificial night lighting disrupts the cycles of nocturnal creatures in potentially devastating ways.
While research is still ongoing, it is becoming apparent that both bright days and dark nights are necessary to maintain healthy hormone production, cell function, and brain activity, as well as normal feeding, mating, and migratory behavior for many species, including humans.
What is glare? Glare is a visual sensation caused by excessive and uncontrolled brightness. It can be disabling or simply uncomfortable. It is subjective, and sensitivity to glare can vary widely. Older people are usually more sensitive to glare due to the aging characteristics of the eye. Disability glare is the reduction in visibility caused by intense light sources in the field of view, while discomfort glare is the sensation of annoyance
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or even pain induced by overly bright sources (Rea 2000). Compare the glare from the streetlight shown in Figure 6 to the glare from the luminaires shown . Reducing glare is an effective way to improve the lighting.
Paradoxically, in addition to wasting resources, a nighttime environment that is over-lit results in lowered visibility: direct glare from improperly shielded fixtures is often blinding. Light spilling into the sky does not light the ground where we need it. The redundant lighting found in many urban centers results in a clutter of lights that contribute to sky glow, trespass, and glare while destroying the ambiance of our nighttime environment. Our eyes, when dark-adapted, have good natural capacity in lowlight situations. But when nightscapes are over-lit, eyes never have a chance to become dark-adapted, and areas adjacent
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to brightly lit areas become impenetrable, reducing safety. Some communities have experienced a decrease in crime by reducing or eliminating nighttime lighting in appropriate areas.
How is light trespass measured or calculated? The Institution of Lighting Engineers (ILE) specifies light trespass limits for light entering windows in terms of environmental zones It is difficult to measure light trespass because the occurrences are so different. Illuminance on a vertical plane (for example vertical illuminance at the window, as depicted in Figure 4) may be appropriate in some cases. Horizontal illuminance might be appropriate in other cases (for example, horizontal illuminance on a bed). An illuminance level of 1 lux (0.1 footcandle) might be acceptable to some and completely objectionable to another. For reference, 0.3 lux (0.03 footcandle) is typical of the illuminance that results from moonlight.
In a recent study, Boyce et al. (2001) suggest that light trespass be measured in a relative manner, at property boundaries, to take into account both light coming into the property as well as light inside the property. When designing the lighting for a site, imagine a vertical plane at the boundary between the site property and an adjacent property. Measure the illuminance on the vertical plane at the property boundary, directed toward the lighting design site, 180° away from the adjacent property. Then rotate 180° away from the lighting design site, and measure the illuminance on the vertical plane, directed toward the adjacent property. Calculate the ratio of the illuminance on the plane pointing toward the lighting design site to the illuminance on the plane pointing toward the adjacent property. If the ratio of the measured illuminances is less than unity (one), this implies that the design site receives more light 100
from the adjacent property than the design site delivers to the adjacent property. If the ratio is greater than unity, then the design site delivers more light to the adjacent property than the adjacent property delivers to the site. The larger the ratio, the more likely light trespass complaints are to occur.
Glaring lights can actually reduce visibility. Here the brightest most visible objects in the area are the lighting fixtures, not the roadways, walkways or parking
areas
which
a
driver
or
pedestrian would expect to be lighted. Atlanta, Georgia. Image Credit: International Dark-Sky Association Light pollution wastes money and energy. Billions of dollars are spent on unnecessary lighting every year in the United States alone, with an estimated $1.7 billion going directly into the nighttime sky via unshielded outdoor lights. Wasted lighting in the US releases 38 million tons of carbon dioxide into the atmosphere annually; unshielded outdoor lights are directly responsible for 1.2 million tons of carbon dioxide waste. Simply reducing and removing unnecessary lighting saves money and energy, often at minimal expense. Over-lighting the night neither improves visibility nor increases nighttime safety, utility, security, or ambiance.
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Light pollution affects every citizen. It is a serious environmental concern that wastes money and resources while jeopardizing wildlife, our environment, health, and human heritage. Each of us can implement practical solutions to combat light pollution locally, nationally, and internationally. Find out how by exploring this Web site and others in the “links� section.
What are the effects of light pollution?
Waste of resources: It costs a lot of money to light up homes, public places, sports and commercial places. Apart from the fact that tax payers pay needlessly for this, the nation uses millions of tons of oil and coal to produce the power needed to light the sky. Meanwhile, the environmental cost of producing this energy is another worrying issue that can be discussed at another time. 102
Loss of historical and cultural value: Astronomers are concerned that not only do they have difficulty reading and viewing activities in the sky and outer space, but also we are loosing the wonderful dark sky view with stars and other space objects that we used to enjoy. Many young people growing up in the city may not have the opportunity to experience
this
awesome
scene,
if
we
continue
to
direct
more
light
into
the
sky.
Health implications: Disability glare, eye strain, loss of vision and stress that people get from glare and spillovers are worth mentioning. Our eyes naturally adjust during day and night so we can see things properly. Too much light can harm our eyes and also the harm the hormones (such as melatonin) that does this job.
Wildlife: Many insects, birds, mammals and reptiles are photoperiodic in nature. Examples include sea turtles. Many aspects of their physiology and behavior are influenced by day–night or circadian rhythms. This means their eating, mating, growth and development, movement and other activities are in relation to the balance of day and night.
Artificial lights, even in small amounts can distort their natural operations and cycle. Thousands of deer and animals are killed on the roads by vehicles in the evenings, because the glare of these cars blind them and are unable to run off the streets before they are knocked down.
Light pollution and hatchlings sea turtles Sea turtles live in water. When mature female turtles are ready to lay eggs, they come over to the sandy shore and find a dark place to lay their eggs. They dig a shallow hole in the sand, burry the eggs there, and return to the ocean. 103
After incubating for about two months, the eggs are hatched, and the hatchlings turtles stay beneath the sand until the temperatures and conditions are right to come out.
With the right conditions, they wave their way onto the surface in the night, and move to the ocean with the help of natural lights reflecting on the sea. Baby sea turtles naturally move towards moonlight reflection in the hope of getting into the ocean.
Unfortunately, our beaches are full of artificial lights from beach houses, car parks and security lights. As a result, the baby sea turtles are deceived, and move towards these artificial lights. Many of them are harmed and killed before they find their way to the ocean.
Egg laden turtles need dark quiet sandy beaches to lay their eggs, just as the hatchlings also depend on natural skylights to giude them to the waters. There are bound to be disorientations when we flood our beaches and nearby living areas with bright artificial lights.
The Effects of Light Pollution on the Environment How does light pollution impact the natural environment? After all, it is just light, so how harmful can it be? Well, it’s worse than you might think. In fact, light pollution can affect the areas surrounding our cities for tens or even hundreds of miles, reaching leaves no living thing ever untouched. Ultimately, light causes problems for the environment because both plants and animals live on a 24-hour cycle dictated by the Sun. As life evolved on Earth, creatures became accustomed to the day and night cycle and passed this familiarization on through their genes. This rhythm is known as the “circadian rhythm.”
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For those of you who have ever traveled between time zones, you will usually notice a ‘change’ in your own circadian rhythm. If you go to sleep at 11pm and wake up at 7am on a daily basis, then travel to a time zone 3-hours behind you, your circadian rhythm will take a few days to adjust – this is traditionally known as ‘jet lag,’ that sleepy, lethargic sense you get when you travel. Wildlife is no different. The very recent arrival of the powerful artificial light has dramatically (and negatively) affected animal behaviors in mating, migration, sleeping, and hunting.
MAMMALS: Nocturnal animals have evolved to function at night. The night, in a very real sense, is a very important part of their environment–no different than trees and food. Their eyes are very sensitive to light, similar to your eyes when you first wake up or walk out of a dimly lit room into the sunshine. Animals such as bats, raccoons, coyotes, deer, and moose rely on the dark for a variety of natural functions.
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These species, among others, experience a decline in reproduction and a difficulty foraging for food. In addition, predators that would normally be unable to see these nocturnal creatures are able to do so with more ease, causing an increased mortality rate as a result of both the predator’s ability to see their prey more easily and the prey’s inability to get away due to vision impairment.
BIRDS: imagesMany species of birds migrate and or hunt at night. They depend upon the dark and the stars to find their way. Their sensitivity to dim star-light makes them extremely vulnerable to bright city lights. Because of this, 100-million birds die each year in North America due to collisions with lighted buildings and towers. Migrating birds have been known to be pulled far off course due to light pollution, which prevents them from reaching their natural destination.
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Birds have also been known to fly into lighthouses, wind turbines, and sea-based drilling platforms, along with many other lighted obstructions.
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REPTILES:
It wouldn’t be fair to talk about light pollution without mentioning turtles. Female sea turtles like to nest on remote and dark beaches. Naturally, coastal cities and their haze of light pollution make the beaches brighter and discourages nesting. In addition, sea turtle hatchlings are often confused by the city lights and instinctively crawl towards the city instead of the ocean, resulting in millions of deaths a year.
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Naturally, nearly every species of nocturnal reptile is affected for many of the same reasons previously listed. Of course, the list goes on, but those are some of the highlights of the detrimental effects of artificial lighting on the environment. By lighting responsibly, we are able to restore the ecosystem of the night in exactly the same way we plant trees or establish national parks to help protect and restore those environments. Lighting responsibly is just the next step in being a part of the natural environment‌ instead of lording over it
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SOURCES:
1) Household air pollution and health. Fact sheet N°292. WHO, http://www.who.int/mediacentre/factsheets/fs292/en/ 2) Indoor Air Pollution. Medline Plus., http://www.nlm.nih.gov/medlineplus/indoorairpollution.html 3) Indoor air. The Department os Environment, Australia: http://www.environment.gov.au/topics/environment-protection/air-quality/indoor-air 4) Indoor Air pollution, Edugreen. http://edugreen.teri.res.in/explore/air/indoor.htm 5) Carbon monoxide poisoning, NHS UK., http://www.nhs.uk/conditions/carbon-monoxidepoisoning/Pages/Introduction.aspx 6) What is Air Pollution: EPA Victoria., http://www.epa.vic.gov.au/air/aq4kids/main_pollutants.asp 7) Asthma and Air Pollution., Natural Resources Defense Council: http://www.nrdc.org/health/effects/fasthma.asp 8) Air Pollution And Health, Environmental Protection UK. http://www.environmentalprotection.org.uk/committees/air-quality/about-air-pollution/air-pollution-and-health/ 9)
Passchier-Vermeer W, Passchier WF (2000). "Noise exposure and public health". Environ. Health Perspect. 108 (Suppl 1): 123–31. doi:10.2307/3454637. JSTOR 3454637. PMC 1637786 . PMID 10698728.
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