SOLAR RADIATION

The earth receives all its energy from the sun. Sun is an extremely hot gaseous spherical mass whose surface temperature is 6000 C. This hot gaseous mass is continuously radiation heat energy into space which is known as solar radiation. This energy is radiated from nuclear reactions in its core where the temperature is about 15,000,000 C. But our earth receives a very small percentage of total solar radiation which is only 1/2 of the billionth fraction of the total energy radiated by the sun. This is due to great distance of the earth from the sun (approximately 150 km).

The size of the earth is very small as compared to the sun. Yet this small proportion of solar radiation reaching the earth is of great importance. Being the only major source of energy on earth, it controls many of the physical and all biological phenomena of the earth.

RADIATION POLLUTION

Radiation is the emission of rays and particles from a source. We live in the midst of continuous flow of radiation. Natural radiation comes from the sun, other other objects in space and rocks and mineral in the earth.Artificially produced radiation is widely used in fields of communication, industry, medicine and research. Most scientist believe the amount of radiation to which we are exposed is not harmful. But large does of radiation cause biological and chemical changes in living tissues. Illness and even death can result due to excessive amount of radiation.
It was only after the advert of nuclear weapons that the exposure levels have increased enormously. The menace of radioactive pollution spreading into the environment has increased extensively as a result of the discovery of artificial radioactivity, particularly due to the development of atoms bomb, hydrogen bomb and of techniques harnessing nuclear energy.
 A large quantity of long-lived radio nuclides are  released to the atmosphere during nuclear test. The tests may also result in fallout of radioactive substances on surface.
Leakage of nuclear radiations from nuclear reactors has also increased.Even the proper handling of radioactive substances and use of techniques of shielding screens for preventing radiations, cannot stop radiation leak out from these reactors.

 

PRIMARY POLLUTANTS AND SECONDARY POLLUTION

Those substances emitted directly from an identifiable source. These pollutants exist as such after being released into the environment. EX are sulphur dioxide, nitrogen oxides, particulate matter, carbon monoxide, etc.

These are substances, derived from the primary pollution by chemical reactions. For EX primary pollutants such as hydrocarbons and nitrogen oxides, react in the presence of sunlight to form compounds like oxyacetylene nitrate as secondary pollution.

POLLUTION

Pollution can be defined as any unwanted addition of substances to air, water, soil, or food that threatens the health, survivals or activities of humans or other living organisms. Pollution can enter the environment naturally or through human activities.

Pollutants when released into the environment gain entry into soil by absorption, into water by dissolution and into air by evaporation. Both air and water are effective means of transfer and transport of the waste gases and other materials. Soils on the other hands are stationary entities, which are indirectly effected by pollution of water and air.

As soon as a pollutants enter the environment, agencies of transfer, transport and transformation start acting on them almost simultaneously. while the pollutants are dispersed in the medium and diluted, they also undergo a bio tic transformation where in solar radiation, water and air play important roles.

The pollutants may thus be broken down or altered in the a bio tic environment itself.