Notes on Air and Water Pollution | Grade 8 > Science > Environmental Degradation and its Conservation | KULLABS.COM

Air and Water Pollution

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Air pollution

An undesirable change in the physical, chemical or biological characteristics of air is called pollution. The substances which pollute the air called pollutants.

Causes of air Pollution

Different gasses, dust, smoke, disposed of wastes and garbage, etc. are pollutants. These substances make the pollution in the air and the air mixed with these substances is called polluted water. Air pollution may be caused by natural process or by human activities.

Air pollution caused by natural process

Some of the natural processes which cause air pollution areGases and particulate matter released along with lava from the volcanic eruption, the dust raised from the ground during strong winds and storms, smoke from forest fires and fog. The finely divided solid or liquid particles suspended in the air called particulate matter i.e. dust, smoke, fumes. Apart from these, decomposition of plant and animal remains and pollen grains also cause air pollution.

Air pollution caused by human activities
  1. Mixing of smoke in the air: People burn fuels like coal and petroleum products to obtain heat and electric devices and to transport vehicles. All these produces a lot of smoke. The smoke emitted by various sources like a kitchen, factories, airplanes, explosive materials, vehicles, acid rain, carbon monoxide, firewood, etc. are very harmful to human beings and pollute the air badly. It destroys vegetation and crop plants. It also stops the growth of plants.
  2. Mixing of dust particles in the air: The small particles which are fixed in the air is called dust. It is another factor which causes air pollution. Dust particles, if inhaled, cause various allergic reactions in the human body. They may cause diseases like bronchial asthma and other lung diseases. Polluted air contains lead particles which are very poisonous substance. It reaches into the human body by respiration and keeps on accumulating in the tissues of human body. It causes mental disorder and muscular paralysis and abnormalities in pregnancy.
  3. Mixing of bad odour (smell) in the air: The bad smell comes out from the deposit of organic wastes. Wastes also cause pollution in the air. Due to improper management of clearing system, dumping site, and leaking sewage, solid wastes and pollution are increasing day by day. The gas produces from the organic solid wastes and participates matters are sulfur dioxide (SO), nitrogen dioxide (NO) and carbon (C). These gasses mix with air and pollute the air and the whole environment as well. Sulfur dioxide causes lung diseases in human beings such as bronchitis.

Effects of Air pollution

  1. Air pollution causes respiratory tract infection (RTI) and asthma.
  2. It deteriorates the cultural heritage and trees.
  3. It brings various skin and eye allergy.
  4. It is the main causes of global warming
 

Water pollution

Degradation in the quality of water is called water pollution. Water covers over the 3/4th part of the Earth’s surface. It is one of the very important resources for people and the environment. Water pollution affects drinking water, rivers, lakes and oceans all over the world. In many developing countries, it is usually a leading cause of death, as people use impure water for drinking. Drainage and wastage from industries, laboratory, hospitals, and homes are the main factors that cause water pollution.

Causes of water pollution

There are various causes of water pollution. Main causes of water pollution are described below:

  1. A mixture of Drain in water: In urban areas, drainage and drinking water pipe are brought through the same route. If drainage pipe gets burst then drinking water pipe gets contaminated with drain water which pollutes the water.
  2. Washing and Cleaning near water resources: In rural areas, many people shares common tap where they wash their clothes and bath nearby water resources which pollute water.
  3. Mixing of Fertilisers in Water: Farmers use different fertilizers on their farm which are carried to a river by rainfall. Fertilizers get mixed with the river.
  4. Wastage from different sectors: Wastage produced by hospitals, industries, and houses are thrown in the river. Due to lack of garbage disposal water gets polluted.
  5. Mismanagement of drain: Drains are directly thrown into the water in urban areas. Sometimes people directly throw wastage in water.

Effects of water pollution

  1. Water pollution causes water-borne disease like diarrhea, dysentery, and cholera.
  2. It also brings various skin allergy if taken the bath with polluted water.
  3. Acid rain deteriorates cultural heritages.
  4. It has the negative impact on plants.
  5. Aquatic animals cannot survive in polluted water.

 

 

 

 



  • The mixing of dust particles, foul gases and harmful smoke in the atmosphere is called air pollution.
  • The gas produces from the organic solid wastes and participate matters are sulphur dioxide (SO), nitrogen dioxide (NO) and carbon (C).
  • Degradation in the quality of water is called water pollution. 
  • Wastage produced by hospitals, industries, and houses are thrown in the river. 
  • Drainage and wastage from industries, laboratory, hospitals, and homes are the main factors that cause water pollution.
  • Water pollution causes water-borne disease like diarrhoea, dysentery and cholera.
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Very Short Questions

The degradation in the original quality of air due to the mixing of different pollutants is known as air pollution.

Air is polluted by the following ways:

  • By the contamination of smoke.
  • By the mixing of dust and smoke in the air.
  • By spread of foul smell in air.

Its effect on living beings are as follows:

  • It may cause several respiratory diseases, lung diseases, throat itching, etc.
  • Mixing of harmful chemicals in air may cause acid rain.
  • It may decrease the transparency of atmosphere which creates problems for pilots.

Air pollution may cause acid rain which is harmful to all the living beings living in the environment and may severely affect different aspects of nature. Similarly, the acid rain will deteriorate the cultural heritages like temples, gumbas, monuments, etc. by washing away their color, style and so on.

  • Respiratory diseases like lung diseases
  • Cough, cold, heart diseases and many types of cancers
  • Mental, muscular diseases
  • Skin problems like itching
  • Carbon monoxide decreases the oxygen carrying capacity of blood

  • Carbon monoxide
  • Sulphur dioxide
  • Hydrogen sulphate

Vehicles operate by the burning of fossil fuels like petroleum which produces smoke and mix with air causing air pollution.

The major cause of air pollution is the human activities. All the needs of humans are the prime cause of air pollution which they are utilizing for their sophisticated life. So, people themselves are responsible for air pollution.

Air pollution has many negative effects upon the human life as well as upon the natural environment. So, it is essential to stop works that cause air pollution to preserve the environment and reduce the effects upon the human life.

  • Afforestation programmes should be launched
  • Electric vehicles should be encouraged
  • Smokes from industries should be filtered before releasing to the environment
  • Burning of firewood, fossil fuels, etc. should be reduced by using modern technology
  • Factories should be established away from the residential area as far as possible.

Village women use firewood for cooking food which produces smoke in large amount. So, women of the village usually suffer from diseases of respiratory system.

Regular, fast running and big vehicles decrease air pollution because it reduces the number of small vehicles which produces smoke and decreases the level of air pollution. Regular and fast running vehicles decreases the load upon fossil fuel and decrease air pollution.

Two effects causes by human activities are as below:

  1. Water pollution.
  2. Air pollution.

Environment degradation contribution for the population of a number of poisonous gas in the atmosphere like carbon monoxide, Nitrogen oxides, sulphur dioxide, methane etc. which pollutes the environment.

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  • Acid rain is formed when carbon dioxide (CO2) and Nitrogen dioxide (NO2) react with ______.

    water


    carbon


    acid


    oxygen


  • Smog is formed when the smoke coming out of vehicle and industries mix with the ______.

    oxygen


    carbondioxide


    fog


    air


  • Which is the cause of pollution?

    all of the above


    dust


    bacteria


    smoke


  • An undesirable change in the ______characteristics of air is called pollution.

    biological


    physical


    chemical


    all of the answers are correct.


  • Rust is formed when iron reacts with ______ in the presence of water.

    oxygen


    oxidizes


    nytrogen


    carbon


  • Incomplete burning of petrol or diesel in vehicles creates ______ gas which is very poisonous.

    ozone


    methane


    carbon dioxide


    carbon monoxide


  • Combustion of coal in power plant produces mainly ______ which is a major pollutant of air.

    methane


    nitrogen dioxide


    carbon monoxide


    carbon dioxide


  • Which gas is responsible for depletion of the ozone layer around the earth which protects us from harmful?

    Methane


    Chloroflurocarbon


    Hydrogen


    Oxygen


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