Environmental Chemistry: Components of Environment and Global Environmental Damages (For CBSE, ICSE, IAS, NET, NRA 2022)

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The earth has just the right kind of conditions of temperature range, air, water, soil for supporting life and is protected from harmful rays from the outer space by the ozone layer.

Components of Environment

Environment Has Two Components

  • physical or abiotic (non-living) components and
  • living or biotic components.

Abiotic components of environment are air, water, soil, energy radiation, etc.

  • Biotic components of environment are microbes (such as bacteria, algae and fungi) , plants, animals, etc.
  • Environment is the sum total of living and non-living components surrounding an organism.

Global Environmental Damages

Some example of global damages are discuss below:

  • Chlourofluoro carbons (CFCs) , used as refrigerants, and various kinds of sprays or sols (e. g. perfumes, air freshener, etc.) . CFCs cause ozone holes in the ozone layer. Ozone hole refer to depletion of ozone molecules in the ozone layer due to the reaction of CFCs.
  • More ultraviolet radiations reach the earth through the ozone holes and the reflected radiations from the earth are absorbed by water vapour, etc. The trapped radiations release more and more heat resulting in the phenomenon of Global Warming. This effect is also known as Green House Effect.

Pollution

Pollution refers to deterioration or unclean objectionable conditions in the quality of natural resources such as air, water and soil because of the action or presence of unwanted substances beyond a certain limit.

Pollutants

Pollutants are the substances or effect introduced into the environment in significant amounts in solid, semi solid, liquid gas or sub molecular particle form which has a detrimental (bad) effect on the environment.

Types of Pollutants

Natural Pollutants

  • Fires in forests may be caused when lightning strikes the trees. Burning of tree produces a lot of which is released to the atmosphere.
  • Soil erosion increases suspended particulate matter and dust in air. These may even enter water bodies as they are washed down by rain or natural waterfalls.
  • Volcanic eruptions also add pollutants like and solid particles to the environment.

Anthropogenic Pollutants

Pollutants added to the environment through human activities are termed anthropogenic pollutants.

These are of two kinds:

  • Primary pollutants: Primary pollutants are added directly in a harmful form to the atmosphere. E. g. and from burning of fossil fuel; and oxides of nitrogen from vehicular combustion, thermal power stations, etc.
  • Secondary Pollutants: Secondary pollutants are the products of reaction between the primary pollutants and normal environmental constituents.

Thus, a primary pollutant which reacts with oxygen of air to give . Further, reacts with water vapour present in the atmosphere and forms . Thus, and are secondary pollutants.

Depending on the sources. anthropogenic pollutants may be classified further into:

  • Industrial Pollutants: Paper, textile industries, tanneries and distilleries dispose various effluents like oil, grease, plastic and metallic wastes into the environment.
  • Domestic Pollutants: Detergents, fluoride toothpastes, edible Colours, food flavouring agents, polythene bags and wrappers find their way into the environment as pollutants. Methane is produced in cattle stomach and in stagnant paddy fields is also a domestic pollutant.

Sources of Pollutants

Stationary Sources

The pollutants released from a fixed location or a well-defined area is known as stationary source. e. g. smokestacks of power plants, smelters, surface mines, etc.

Mobile Sources

The pollutants released from diffused sources or the sources that move from place to place is termed as a mobile source. e. g. automobiles, buses, aircrafts, ships, trains, etc.

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