Pollution has been defined as, the introduction of harmful materials to our environment.Our environment consists of the atmosphere that gives us the fresh air to breath, Oceans and waterways that sustain life and the landmass.
Atmosphere
The atmosphere generally is in a state of dynamic equilibrium.There are several natural cycles that have been operating smoothly over thousands of years.
Although the amount of water ,as vapour, droplets in mist and clouds and snow and ice, varies widely, the composition of dry air stays fairly constant. Amount of water vapour in the atmosphere ranges from 0 to 4 %. As the temperature rises more water will evaporate from the oceans.
Composition of dry air.(By volume)
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Nitrogen 78 - 79 %
Oxygen 20 - 21. %
Argon 0.8- 1.0 %
Carbon dioxide 0.02 - 0.04 %
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Agents of Air pollution.
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Natural
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Man made
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1. From ground :- Volcanoes and geothermal pools, vents etc,.
Ejects ash, water, CO2, SO2, NO2, and H2S.
2. Decaying of organic matter.
Some bacteria and fungi uses organic matter for nutrition. Then CO2 and CH4 escape.
3. Forest fires.
These release a lot of CO2 , and smoke which consists of water,volatile organic compounds ,smoke that would consist of unburnt carbon and non burning substances.
4. Vegetation.
. Isoprene is a common volatile organic compound VOC, emitted by vegetation, which may be causing asthma.
Plants produce a lot of pollen which that can cause allergies.
5. Lightening.
Very high temperature causes the nitrogen to combine with oxygen forming acidic oxides.
6. Sun light.
Sun powers hurricanes, tornadoes that lifts dust from the earth and spread all over the globe.
UV rays cause oxygen molecules to combine to form ozone which is harmful at lower levels but beneficial at high altitudes.
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Burning.
Up to the farming era burning of wood, fat and vegetable oils for cooking and lighting and setting fire to grasslands for farming did not pollute the earth to a significant extent. But with the discovery and use of fossil fuels, coal and petroleum, we are adding tonnes tonnes of CO2, CO, SO2 on a daily basis.
2. Farming.
Ammonia NH3, gas enters the atmosphere from heavily fertilized fields and animal waste.
Due to the deep ploughing of the land using machinery solid matter from the soil gets airbourne.
Spraying of insecticides and fertilizers.
3. Industry.
Various heavy metals such as lead and mercury enter the atmosphere from manufacturing processes.
4. Homes
Ill ventilated cramped living conditions produce mold and bacteria. Mold and fungi produce spores and dust mites produce allergens.
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Land pollution.
This can occur in two major ways. 1.0 Tampering the earth’s crust.
2.0 Adding unwanted materials.
1.1Tilling:-
This is essential for growing crops, but deep ploughing, using heavy machinery has more long term negative aspects than the benefits.The soil dries up soon and makes it unfavourable for plants and useful creatures such as the earthworms .
The rainwater removes the loosened fertile soil and the valuable salts.
Careless ploughing has resulted in barren lands where it has become impossible to grow crops.
1.2 Mining :-
Excavating for minerals , coal, diamonds and gems has many adverse effects.
Forest land and arable land become almost useless after excavations.
Looses natural beauty and the sites become an eyesore.
Soil gets exposed to wind and water causing erosion.
Causes crust caving in and land slips.
1.3 Drilling.
"Oil and gas drilling can be a dirty business. Drilling projects operate on a 24-hour basis, disrupting wildlife, water sources, human health, recreation and other purposes for which public lands were set aside and held in trust for the American people".-Wilderness society.
1.4 Plastics.
More than 5 Trillion plastic bags are thrown out a year. Out of this only 1% is recycled. Much of it pollutes the land . These are deadly to animals as they eat them as food or as wrappers of food accidentally.
Water Pollution.
Oceans cover three fourths of the earth’s surface, holding over 90% of all the water in the planet.According to National Geographic , “Only 0.007 % of the planet's water is available to fuel and feed its 6.8 billion people”. .
Seawater contains a vast amount of dissolved solids and gases. Yet it is neither poisonouss nor hazardous. While the pH of pure water is 7, the surface seawater has a pH of 8.1 and deeper about 7.8. Aquatic life plankton,corals fish and even mammals like whales thrive in this medium.
Pollution depends on the quantity of pollutant added and the volume of the body of water. Our ancestors never believed that some rivers and oceans could ever be polluted. But now with the unprecedented expansion in population and the advances in technology, they are getting polluted in a very big way.
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Cause of pollution
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Purpose of act.
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Effects on waterways.
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1.Clearing forests
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For wood.
farming and
housing
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Soil erosion and causes soil and organic debris to enter the major waterways and the sea.
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2.Dumping waste,
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Sewage,
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Plastics.
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Easy removal
More than 80 tons of plastics are dumped into the sea every year..
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a.Adding disease causing bacteria,viruses etc.
Depletion of oxygen due to excessive algae growth.
Soap and other detergents, heavy metals and toxic waste from houses and factories .
Waterways can get clogged.
“95 percent is submerged beneath, oceans where it strangles underwater creatures and wrecks the aquatic ecosystem”.
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