Page 206 - New Medley 5 Semester 2

 The harmful gases released by air

conditioners and refrigerators have Knowledge Zone
reduced the thickness of the ozone layer The layer of ozone gas around the
earth, in the upper atmosphere acts
of the atmosphere. as an umbrella over us. It saves us

 Polluted air kills plants and trees by from harmful rays of the sun.
damaging their leaves.

 Burning of fossil fuels has increased the amount of carbon dioxide in the air

which in turn has increased the temperature of the atmosphere over a period of

time. is is called global warming. It is causing a threat to life on the earth.

Controlling Air Pollution

 Trees remove carbon dioxide from the air and release oxygen into it. us,
planting more and more trees can help control air pollution.

 Automobiles should be checked regularly, so that they do not release harmful gases.

 We should use renewable forms of energy like solar energy by using solar

cookers, solar cells, solar heaters, etc. ey do not cause air pollution.

 We should use non-polluting fuels like CNG for cars and buses.

 We should use only eco-friendly sprays, cosmetics and perfumes. ey save
the ozone layer from damage.
2 • Problem Solving

Circle the odd one out.
1. Petrol, Diesel, Coal, CNG
2. Bronchitis, Malaria, Jaundice, Cholera

3. Tree, Aeroplane, Car, Air conditioner
4. Carbon dioxide, Nitrogen, Oxygen, Ozone

AT ONE GO

 The earth is surrounded by a blanket of air called atmosphere.

 The main gases in the atmosphere are oxygen, nitrogen and carbon dioxide.
 Oxygen is the most important of all gases of the atmosphere.
 Air has weight, occupies space and exerts pressure in all directions.

 Polluted air is harmful to our health.

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