“Pollution is the introduction of contaminants into the environment that cause harm or discomfort to humans or other living organisms, or that damage the environment” which can come “in the form of chemical substances, or energy such as noise, heat or light”. “Pollutants can be naturally occurring substances or energies, but are considered contaminants when in excess of natural levels.”
“Pollution is habitat contamination”.
[Explanation of definition - Pollution is “the addition of any substance or form of energy (e.g., heat, sound, radioactivity) to the environment at a rate faster than the environment can accommodate it by dispersion, breakdown, recycling, or storage in some harmless form”.
“Pollution is a special case of habitat destruction; it is chemical destruction rather than the more obvious physical destruction. Pollution occurs in all habitats—land, sea, and fresh water—and in the atmosphere.”
“Much of what we have come to call pollution is in reality the non-recoverable matter resources and waste heat.”
“Any use of natural resources at a rate higher than nature's capacity to restore itself can result in pollution of air, water, and land.”
Perhaps the overriding theme of these definitions is the ability of the environment to absorb and adapt to changes brought about by human activities.
Environmental pollution is “the contamination of the physical and biological components of the earth/atmosphere system to such an extent that normal environmental processes are adversely affected”.
In one word, environmental pollution takes place when the environment cannot process and neutralize harmful by-products of human activities (for example, poisonous gas emissions) in due course without any structural or functional damage to its system.
In fact, “the due course” itself may last many years during which the nature will attempt to decompose the pollutants; in one of the worst cases – that of radioactive pollutants – it may take as long as thousands of years for the decomposition of such pollutants to be completed.
Pollutant - A pollutant is a waste material that pollutes air, water or soil. Three factors determine the severity of a pollutant: its chemical nature, the concentration and the persistence.
Pollution occurs, on the one hand, because the natural environment does not know how to decompose the unnaturally generated elements (i.e., anthropogenic pollutants), and, on the other, there is a lack of knowledge on the part of humans on how to decompose these pollutants artificially.
In modern industrialized societies, fossil fuels (oil, gas, coal) transcended virtually all imaginable barriers and firmly established themselves in our everyday lives.
Not only do we use fossil fuels for our obvious everyday needs (such as filling a car), as well as in the power-generating industry, they (specifically oil) are also present in such products as all sorts of plastics, solvents, detergents, asphalt, lubricating oils, a wide range of chemicals for industrial use, etc.
Combustion of fossil fuels produces extremely high levels of air pollution and is widely recognized as one of the most important “target” areas for reduction and control of environmental pollution.
Fossil fuels also contribute to soil contamination and water pollution. For example, when oil is transported from the point of its production to further destinations by pipelines, an oil leak from the pipeline may occur and pollute soil and subsequently groundwater. When oil is transported by tankers by ocean, an oil spill may occur and pollute ocean water.
Of course, there are other natural resources whose exploitation is a cause of serious pollution; for example, the use of uranium for nuclear power generation produces extremely dangerous waste that would take thousands of years to neutralize.
But there is no reasonable doubt that fossil fuels are among the most serious sources of environmental pollution.
Power-generating plants and transport are probably the biggest sources of fossil fuel pollution.
Common sources of fossil fuel pollution are:
Production and distribution of fossil fuels
Other manufacturing facilities
Road transport (motor vehicles)
Fossil fuel combustion is also a major source of carbon dioxide (CO2) emissions and perhaps the most important cause of global warming. Learn more about the causes and effects of global warming here.
Other (Non-Fossil Fuel) Sources of Environmental Pollution
Among other pollution sources, agriculture (livestock farming) is worth mentioning as the largest generator of ammonia emissions resulting in air pollution. Chemicals such as pesticides and fertilizers are also widely used in agriculture, which may lead water pollution and soil contamination as well.
Trading activities may be another source of pollution.
For example, it’s been recently noted that packaging of products sold in supermarkets and other retail outlets is far too excessive and generates large quantities of solid waste that ends up either in landfills or municipal incinerators leading to soil contamination and air pollution.
Residential sector is another significant source of pollution generating solid municipal waste that may end up in landfills or incinerators leading to soil contamination and air pollution.
In India, the main causes of pollution are :
1. Sewage :
The household sewage usually is taken to and fall in rivers, large tanks and lakes. Urine has urea which produces ammonia by hydrolysis. It is also produced by decay of other nitrogenous substances present in sewage. Thus water gets polluted giving rise to foul smell and becomes useless for drinking and bathing purposes because it may cause various skin diseases.
2. Household detergents:
There are such chemicals which are used for washing clothes, clearing bathrooms, hospitals, etc. These include soaps, surf, nirma, fab etc. Because they are not completely oxidised, they produce CO2, alcohol and organic acids which pollute water and harm living organisms.
3. Pesticides :
These chemicals are sprayed on fields, garden, sewage outlets to kill rats and insects. These chemicals are gases, liquids or solids. DOT is a white coloured substance used to kill insects, flies and worms. SO2 is a colourless gas used to kill insects. Formaldehyde, chlorine, carbolic acid, phenyl, potassium permanganate are other such substances. Lime is used for whitewash of buildings and sewage outlets to kill insects and worms, Bleaching powder (a mixture of chlorine and lime) is used to purify water reservoirs and wells.
These chemicals may become more harmful than useful because they kill many animals that feed upon plants and small animals upon which these chemicals were sprayed. Chemicals which are sprayed by helicopter to kill mosquitos etc. may cause death of many fishes and herbs. Also small insects, earthworms and fungi may be killed due to which fertility of soil is reduced. Pesticides may also cause genetic defects.
4. Weedicides & Herbicides :
Weedicides are some chemicals which control weeds to enter the field and compete with the crops and hence, cause a direct effect on the crop.
Some common weedicides are 2,4-D, Metachlor, Nitofen.
"Herbicides" are basically used to kill undesired plants. Their toxicity depends entirely on what you are using. Some are virtually harmless to humans (like Roundup), some are lethal (like Paraquat).
Weedicides, Herbicides get mixed with the soil and cause soil pollution.
5. Smoke :
Smoke released from industrial plants, fuel and railway engines cause air pollution. Smoke mostly consists of CO2 and water vapour. Along with these carbon monoxide and other carbon containing compounds, nitrogen are also present which cause air pollution if their amount increases. These cause respiratory trouble and ill effects on eye.
6. Automobile exhausts :
Jet planes, tractors, motor, buses and scooters etc in which petrol, diesel and kerosine is burnt produce different gases which are cause of air pollution.
7. Chemical discharge from industries :
Industrial effluents decreases oxygen in water. The amount of chlorides, nitrates and sulphates increases. By discharge of effluents into rivers most rivers of country become polluted and water becomes toxic to fishes and aquatic plants. Lead, Zinc and Iron compounds specially contribute to the pollution.
8. Decay and putrefaction of household wastes and dead bodies :
With death of animals, certain anaerobic bacteria putrefy the dead body as a result of which ammonia and H2S are produced giving foul smell. This causes air pollution.
9. Radioactive substance :
This topic has already been discussed in section of radioactive pollution.
10. Biopollutants :
Some of the allergic diseases like asthma, common cold, eczema and other skin ailments are caused by biological organisms like fungal spores, pollen, bacteria. Some higher plants that are allergic are, kikar, mulberry, castor (Ricinus), carrot weed (Parthenium) and Chilbil (Holoptelea).
Why does pollution matter?
It matters first and foremost because it has negative impacts on crucial environmental services such as provision of clean air and clean water (and many others) without which life on Earth as we know it would not exist.
When pollution started in human history?
Although pollution had been known to exist for a very long time (at least since people started using fire thousands of years ago), it had seen the growth of truly global proportions only since the onset of the industrial revolution during the 19th century.
The industrial revolution brought with it technological progress such as discovery of oil and its virtually universal use throughout different industries.
Technological progress facilitated by super efficiency of capitalist business practices (division of labour – cheaper production costs – overproduction – overconsumption – overpollution) had probably become one of the main causes of serious deterioration of natural resources.
At the same time, of course, development of natural sciences led to the better understanding of negative effects produced by pollution on the environment.
Environmental pollution is a problem both in developed and developing countries. Factors such as population growth and urbanization invariably place greater demands on the planet and stretch the use of natural resources to the maximum.
It’s interesting to note that natural resources had been stored virtually untouched in the Earth for millions of years. But since the start of the industrial revolution vast amounts of these resources had been exploited within a period of just a couple of hundred of years at unimaginable rates, with all the waste from this exploitation going straight in to the environment (air, water, land) and seriously damaging its natural processes.
Types of Environmental Pollution
- Air pollution
- Water pollution
- Soil pollution (contamination)
- Noise pollution
- Thermal pollution