Pollution 

Pollution is the unfavorable alteration of our environment, largely as a result of human activities (Southwick; 1976)

We can explain it as ‘Pollution is an undesirable change in physical, chemical, and biological characteristics in our air, land, and water that is harmful or may harm future organisms’.

The actions such as construction, transportation, and manufacturing, not only deplete natural resources, but even produce a large number of wastes that lead to pollution of air, water, soil, and oceans, which also causes global warming and acid rains.

What are pollutants?

Pollutants are physical, chemical, or biological substances which unintentionally released directly or indirectly into the environment and are harmful to live organisms.

These harmful contaminating agents are called pollutants. For Example, Domestic sewage and runoff from agricultural fields, pesticides, and fertilizers, oxides of nitrogen, sulfur dioxide, carbon dioxide, and carbon monoxide.

Types of pollution

Pollution is of the following types:

  • Air pollution
  • Noise pollution
  • Water pollution
  • Soil pollution
  • Radiation pollution
Air pollution

The presence of any solid, liquid, or gaseous substance along with noise and radioactive radiations in the air/atmosphere in such concentration that may be directly and indirectly injurious to humans or other living organisms, plants, the property is referred to as Air pollution.

For example, Chlorofluorocarbons (CFCs) are used in refrigerators, air conditioners, and aerosol sprays. CFCs damage the ozone layer of the atmosphere.

Types of Pollution

Types of Pollution

Types of air pollution

Air pollution can be of two types: Natural pollution (originated by the natural process- Forest fire, volcanic ash) and Anthropogenic Pollution (Originates by man-made pollutions).

There are two types of air pollutants:

  • suspended particulate matter
  • gaseous pollutants like Carbon monoxide, NOx, etc.

Particulate pollutants: These matter suspended in the air is dust and soot released from the industrial chimneys.

  • Their size ranges from 0.001 to 500 μm in diameter. Particles less than 10μm float and move freely in the air.
  • Particles less than 0.02 μm form persistent aerosols.
  • The major source of SPM (suspended particulate matter) are vehicles, power plants, construction activities, oil refineries, the marketplace, industries, etc.

Fly ash: Tiny particles released with smoke from the exhaust of factories and power plants that contain harmful materials(SPM) as by-products of coal-burning operations.

  • Fly ash pollutes air and water and may cause heavy metal pollution in water bodies.
  • Fly ash affects vegetation as a result of its direct deposition on leaf surfaces or indirectly through its deposition on soil

Greenhouse gases:

Carbon dioxide, methane, nitrous oxide, water vapor, and chlorofluorocarbons are capable of trapping out-going infrared radiation from the earth. Thus, the temperature of the global atmosphere got increased. These gases are known as greenhouse gases and the heating effect is known as the greenhouse effect.

  • Due to the heating effects of greenhouse gases, turn of the century the temperature may rise by 5°C.  This temperature rise will melt the polar ice and increase the sea level leading to coastal flooding.
Sources and effects of gaseous pollutants:
Pollutant Sources Harmful effect
Carbon compounds (CO and CO2) burning of wood, coal, other combustion, automobiles, etc. Respiratory problems (lung-related diseases) Greenhouse effect
compounds of sulphur(SO2 and H2S) Power plants and refineries, volcanic eruptions Respiratory problems in humans Acid rain
Nitrogen Compound (NO and N2O) Motor vehicle, atmospheric reaction Irritation in eyes and lungs, Low productivity in plants, Acid rain.
Hydrocarbons (benzene, ethylene) Automobiles, petroleum industries The respiratory problem, Causing Cancer
SPM (Suspended Particulate Matter)  Any solid and liquid particles suspended in the air Thermal power plants, metallurgical processes, Construction activities, and automobiles Poor visibility, breathing problems. Smog (smoke & fog) formation leads to poor visibility and aggravates lead) asthma in humans
Fibers (Cotton, wool) Textiles and carpet industries Lung disorders


Acid rain

Acid rain can be defined as the presence of acids in the rain. Normal rainwater i.e. H2O + CO2 is a weak acid with a pH of 6.5. Acid rain consists of acids with a pH of 5.6 to 4. formation of acid rain is due to nitrogen oxide (NOx), SO2, and Hydrocarbons formed during the combustion of coal and petroleum. These are highly reactive in air and produce acids H2SO4 or HNO3. 

Impacts of acid rain:

  • Acid rain has adverse impacts on the forests, freshwaters, and soils.
  • It is killing insect and aquatic life forms, causing the paint to peel, corrosion of steel structures such as bridges, and weathering of stone buildings and statues as well as having its bad impacts on human health.
Prevention of Air pollution
  • The use of cleaner fuels such as biogas, CNG, and electricity prevents air pollution.
  • The emission standards for automobiles have been set which if followed will reduce pollution. Standards have been set for the durability of catalytic converters which reduce vehicular emission.
  • Segregation of waste, pre-treatment at sources, and sterilization of rooms will help in checking indoor pollution.
  • Prevention and control of industrial pollution can be reduced by using cleaner fuels, filters, electrostatic precipitators, inertial collectors, scrubbers, etc.
  • shifting polluting industries away from cities and heavily populated areas
  • The belt of trees is best for air purification.

Noise pollution

Any sound which is unwanted for the recipient or any sound without value may be called noise. There are many sources of noise pollution such as steel forgings, loudspeakers, movement of heavy transport vehicles, railways and airports leads to irritation, all these create noise pollution.

  • This leads to irritation and increased blood pressure, loss of temper, decrease in work efficiency, and loss of hearing which may be at first temporary but can become permanent in the case noise stress continues. emotional problems mental depression, annoyance, etc. commonly caused by noise pollution.
  • The level of Noise is measured in terms of decibels (dB). W.H.O. (World Health Organization) has prescribed optimum noise levels as 45 dB day time and 35 dB during the night.
  • Anything above 80 dB is hazardous in terms of health.
control of noise pollution

By better designing and proper maintenance of vehicles, Road traffic noise can be reduced

  • Industrial noises can be reduced by soundproofing equipment like silent generators and areas producing a lot of noise.
  • Power tools, very loud music, land movers, public functions using loudspeakers, etc. should not be permitted at night.
  • Green belts of trees are efficient noise absorbers.
Water Pollution:

Water pollution is one of the most serious environmental problems for us. Due to several activities, many harmful substances are mixed in water, which is hazardous for lives and the environment. Water pollution is caused by human activities such as industrial, agricultural, and domestic activities by which undesirable harmful substances get added to water.

Natural sources of pollution of water are soil erosion, leaching of minerals from rocks, and decaying of organic matter as all these spoils the quality of water.

The water of the Sea is always get polluted by oil leakage from ships, oil tankers, and pipelines that kills marine birds and adversely affects other marine life and the ecosystem.

Types of water pollution

Water pollution can be categorized as point source pollution and non-point sources

Point source pollution- When pollutants are discharged from a specific location such as a drainpipe, carrying industrial effluents discharged directly into a water body it represents point source pollution.

Non-point sources pollution- In this category the discharge of pollutants from diffused sources or a larger area such as runoff from agricultural fields, grazing lands, construction sites, etc.

  • The improper disposal of sewage, dumping of farmyard manures and agricultural chemicals, and industrial effluents are causes pollution of groundwater

Water pollutants and important reasons for pollution:

Pesticides in Farming such as DDT: Contaminates water bodies. Aquatic organisms take up pesticides from water and get into the food chain, At a higher trophic level, they get concentrated and may reach the upper end of the food chain.

The pollutant of Industries: Metals like lead, zinc, arsenic, copper, mercury, and cadmium in industrial waste go into the river, water polluted by these metals adversely affect humans and other animals.

  • Arsenic pollution of groundwater has been reported from West Bengal, Orissa, Bihar, and Western U.P.
  • Consumption of such arsenic-polluted water leads to accumulation of arsenic in the body parts like blood, nails, and hairs causing skin lesions, rough skin, dry and thickening of the skin, and skin cancer.
  • water bodies polluted by mercury cause Minamata disease in humans and dropsy in fishes.
Control of water pollution

Water pollution can be controlled by the following processes:

  • The sewage water should be treated to make it safe for disposal into water bodies like rivers, lakes, etc.
  • Industrial waste should be avoided disposed of in rivers.
  • Reduce, reuse, and recycling of water should be our mantra.
  • The recycling of water after treatment should be practiced to the maximum extent possible to do.
Some important facts and initiatives
recently a study by the World Wide Fund for Nature (WWF) found that Ganga is one of the ten most endangered rivers in the world.
An ambitious plan to save the river called the Ganga Action Plan was launched in 1985.
Now, the Government of India has launched a new initiative known as National Mission for Clean Ganga (NMCG) in 2016.
Soil Pollution

The addition of any substance that affects the quality of soil or its fertility adversely is referred to as soil pollution. In general, polluted water also pollutes the soil.

Wastes like plastics, cloth, glass, metal and organic matter, sewage, sewage sludge, etc. added to soil cause pollution of soil. Acid rain and dry deposition of pollutants on the land surfaces also contribute to soil pollution.

  • The contamination of soil badly affects our food production and health also.
  • With these actions, our crop production decreased and economic value also gets worse.

    To control soil pollution

    • It is essential to stop the use of plastic bags and instead use bags of degradable materials like paper and cloth.
    • Sewage should be treated properly before using as fertilizer and as landfills.
    • The wastes from industries before disposal should be properly treated for removing hazardous materials.
    • Biomedical waste should be separately collected and incinerated in proper incinerators.

    Radiation pollution

    The radiation emanating from the decay of radioactive nuclides is a major source of radiation pollution. We can categorize radiation into two groups:

    1. Nonionizing radiations
    2. Ionizing radiations

    Non-ionizing radiations: These constitute the electromagnetic waves at the longer wavelength of the spectrum ranging from near infra-red rays to radio waves.

    • The nonionizing radiations are not strong enough to ionize the atoms and molecules of the medium through which they pass.
    • For example – In a microwave, with the help of radiation, the temperature of water rises due to the faster vibration of molecules which helps in cooking.

    Ionizing radiations: These cause ionization of atoms and molecules of the medium through which they pass.

    • Electromagnetic radiations such as short-wavelength ultraviolet radiations (UV), X-rays, and gamma rays produced in nuclear processes, electrically charged particles like alpha and beta particles produced in radioactive decay, are highly damaging to living organisms.
    • The ionizing radiations cause damage to biological systems and are, therefore, these are pollutants.
    • The damages of radiation may be Somatic damage and Genetic damage.
    • somatic damage – Effects of somatic radiation damage include reddening of the skin, loss of hair, ulceration, fibrosis of the lungs, the formation of holes in tissue, a reduction of white blood cells, and the induction of cataracts in the eyes. Somatic damage does not pass through the next generations.
    • genetic damage- This damage can cause genetic damage from gene mutation resulting in abnormalities. Genetic damages can be passed to the next generation.

    For more information about preventive laws of the Environment click here- List of Environmental laws

    References: https://en.wikipedia.org/wiki/Acid_rain

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