E-learning Class 8 Free Tutorial CBSE Science Air Pollution



introduction the little girl is crying she's finding difficult to breathe see this old man he lives in the busy area of a city he is suffering from lung disease air pollution is the root cause for their sickness in this lesson we will study about the harmful changes taking place in our surroundings and their effects on our lives objectives at the end of this lesson you will be able to explain air pollution its sources its harmful effects and its prevention explain depletion of ozone layer describe greenhouse effect explain the formation of acid rain air is necessary for our lives but air is getting polluted day by day due to presence of unwanted substances in it now you would like to know from where these substances come these are released when fuels burn in vehicles or factories and power plants produce them as gaseous waste which substances pollute air the toxic gases like carbon dioxide sulfur dioxide nitrogen dioxide and carbon monoxide these are often released by the engines of vehicles like trucks and buses sometimes they may come from natural sources like smoke and dust arising from forest fires or volcanic eruptions these gases can make healthy people sick and sick people even worse they affect your eyes and throat in some cases they can permanently damage your lungs and even cause cancer have you heard of smog smog is made up of smoke and fog smoke generally contains oxides of nitrogen and other air pollutants the smoke causes breathing difficulties such as asthma cough and wheezing in children let us learn about ozone layer it is a layer of ozone gas in the upper atmosphere of Earth what is its role it protects us from harmful ultraviolet rays of the Sun things like air conditioner refrigerators and fire extinguishers release chlorofluorocarbons CFCs into the atmosphere and create holes in the ozone layer CFCs are another type of air pollutants what can we do to reduce the ozone hole we can replace CFCs with less harmful substances to save the ozone layer from depletion these are the images of Statue of Liberty in New York and Taj Mahal in Agra they are badly damaged due to acid rain Juno what causes acid rain industries and vehicles release toxic gases like sulfur dioxide and nitric oxide into the atmosphere these gases react with the water vapors present in the atmosphere to form sulfuric acid and nitric acid which fall as acid rain what can reduce the acidic rain use of clean fuels like compressed natural gas CNG and liquefied petroleum gas LPG can reduce the acidity of rain it's freezing this may have ruin the plants you know there is a way to save these plants from this extreme cold what is that we can use greenhouse effect to protect them from cold Oh what is clean house effect see this house this has so many glass panes this is called greenhouse when solar rays come into this house heat up the air inside it that hot air is trapped inside which makes nice warm and humid environment for plants to grow similarly the greenhouse gases like carbon dioxide methane and nitrous oxide in the atmosphere act like glass panes when the sun's radiation reaches our atmosphere some rays are reflected back into space and some are trapped into greenhouse gases causing the atmosphere of the earth to warm up global warming means earth is heating up scientists believe that earth's temperature is going to increase even more in coming years scientists say that the greenhouse gases like carbon dioxide trapped the heat from sun and increase the temperature of Earth's atmosphere can you imagine the consequences of heating of Earth's atmosphere it will melt the ice at poles causing the sea levels to rise which could flood the low-lying areas thus affecting the habitats of plants animals and people students can you tell what should we do to reduce air pollution there are many things we can do we can use clean fuels such as CNG LPG and unleaded petrol instead of fossil fuels we can use solar energy hydropower and wind energy we can also plant new trees rather than burning the dry leaves we can put them in a compost pit we can walk more switch over to bicycles for covering small distances and use public conveyances Samri let us summarize what we have learned air pollution is the contamination of air by unwanted substances air pollutants are the substances that pollute air carbon monoxide nitrogen oxides carbon dioxide methane and sulfur dioxide are the major pollutants of a increasing levels of greenhouse gases like co2 are leading to global warming

7 Comments

  1. SHUBHA KUNDU said:

    its a nice video . it is very easy to understand

    June 28, 2019
    Reply
  2. rishabh khakhar said:

    nice

    June 28, 2019
    Reply
  3. vini kumar said:

    Very helpful sir keep it up

    June 28, 2019
    Reply
  4. Anil Doshi said:

    Very helpfull in study and easily understand a lesson🙂

    June 28, 2019
    Reply
  5. Sangita Srivastava said:

    Video contains knowledge and effective materials

    June 28, 2019
    Reply
  6. aravind kumar said:

    very helpful video easy to understand

    June 28, 2019
    Reply
  7. siddhant kumar said:

    Very good video

    June 28, 2019
    Reply

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