Introduction to Air Pollution

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Air pollution

Air pollution occurs when the air contains gases, dust, fumes or odour in harmful amounts. That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials.

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Ozone depletion

Ozone depletion is the term commonly used to describe the thinning of the ozone layer in the stratosphere. Ozone depletion occurs when the natural balance between the production and destruction of ozone in the stratosphere is tipped in favour of destruction.

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Causes of air pollution

The main causes of air pollution are as follows:
(a) Exhaust from Automobiles: Most of the automobiles use fossil fuels. Burning of fossil fuel releases carbon dioxide and carbon monoxide. Carbon dioxide is a greenhouse gas. Carbon monoxide is a poisonous gas even at low concentrations.
(b) Exhaust from Factories and Power Plants: Coal is the main fuel being used in factories. Burning of coal produces carbon dioxide and oxides of sulphur. Oxides of sulphur and nitrogen form acid rain when they mix with rainwater. Acid rain is harmful for living beings and also for buildings and monuments.
(c) Chlorofluorocarbons (CFCs): These are compounds of carbon and halogens and are used as refrigerant. These are also used in pressurized cans. Excess level of CFCs in the atmosphere damages the ozone layer. Ozone layer works like a shield and prevents the harmful ultraviolet radiations from reaching up to the living beings. Any damage in the ozone layer can be very harmful.
(d) Suspended Particulate Matters (SPMs): Some fine particles remain suspended in the air. These are called suspended particulate matters. Stone quarries and various other factories contribute to SPMs.

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Ozone gas

Ozone is a colourless, odourless reactive gas comprised of three oxygen atoms. It is found naturally in the earth's stratosphere, where it absorbs the ultraviolet component of incoming solar radiation that could be harmful to life on earth.

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Ozone layer

The ozone layer is a deep layer in the stratosphere, encircling the Earth, that has large amounts of ozone in it. The layer shields the entire Earth from much of the harmful ultraviolet radiation that comes from the sun.

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Location of ozone layer

The Ozone layer is actually located in the stratosphere in a region that is 10 to 50 km above the Earth.