Lesson: Pollution of Air and Water

Exemplar

Air is a mixture of various gases. One of the gases is 21% part of the air and is essential for the survival of human beings.

This gas is:

(a) Nitrogen

(b) Oxygen

(c) Ozone

(d) Argon

b

Which of the following is not a source of air pollution?

(a) Automobile exhaust

(b) Burning of firewood

(c) Windmill

(d) Power plant

c

Boojho wishes to contribute in reducing air pollution. Which vehicle should he use for going to school?

(a) Car

(b) School bus

(c) Auto rickshaw

(d) Scooter

b

Which of the following is not a way to conserve water?

(a) Replace

(b) Reduce

(c) Reuse

(d) Recycle

a

The type of pollution which is likely to affect Taj Mahal in Agra to a greater extent is:

(a) Air pollution

(b) Water pollution

(c) Soil pollution

(d) Noise pollution

a

Incomplete combustion of fuel such as petrol and diesel releases ___________.

(a) Nitrogen oxide

(b) Sulphur dioxide

(c) Carbon monoxide

(d) Carbon dioxide

c

The phenomenon of marble cancer is due to:

(a) soot particles

(b) CFCs

(c) fog

(d) acid rain

d

Potable water is the water which is:

(a) Obtained from a river.

(b) Obtained from a lake.

(c) Pure and fit for drinking.

 (d) Used only for washing clothes.

c

Which of the following procedures will give you water that is free from all impurities?

(a) Adding chlorine tablets

(b) Distillation

(c) Boiling

(d) Filtration

b

A pond contains clean water. Which of the following activities will produce least pollution of water?

(a) Washing clothes in the pond

(b) Animals bathing in the pond

(c) Washing motor vehicles in the pond

(d) Swimming in the pond

d

Lakhs of trees are planted by people in the month of July every year.

The occasion is called _____________.

(a) Forest Conservation Day

(b) Plantation month

(c) Van Mahotsav

(d) Wildlife week

c

Which of the following is not a green house gas?

(a) Nitrogen gas

(b) Water vapour

(c) Methane gas

(d) Carbon dioxide

a

Name the chemicals which are used in refrigerators and air conditioners and damage ozone layer when released in air.

Chlorofluorocarbons (CFCs)

Name any two sources which cause air pollution due to suspended particulate matter.

(a) Burning of fossil fuels

(b) Industrial activities

Name two gases which are mainly responsible for acid rain.

Following are the two gases which are mainly responsible for acid rain:

(a) Sulphur dioxide

(b) Nitrogen dioxide

The quality of air at various locations is monitored regularly by government and other agencies? In what way can you use these data?

The data gathered from various locations help us to analyse the pollution level at various places, and from these analyses, control measures are chalked out accordingly.

Combustion of fossil fuels generates a lot of air pollution. Can you suggest any two alternative sources of energy which do not cause any pollution?

(i)                 Solar energy

(ii)              Wind energy

Name any two water pollutants which are toxic for plants and animals.

(i)                 Lead

(ii)              Arsenic

Short Answer Questions

A lot of dry leaves are collected in a school garden and are burnt every day. Do you think that it is right to do so? If not, what should be done to dispose off the dry leaves?

Burning dry leaves releases gases such as carbon monoxide, carbon dioxide and other toxic gases, which pollute the air we breathe in. To overcome this, dry leaves can be converted into compost and used as organic manure.

The level of air pollution is higher at a busy traffic intersection. Why?

Large number of automobiles stops at signals for an average of few or more minutes and exhaust toxic fumes in the form of gases.  Due to this reason traffic intersections are always highly polluted.

Fill in the blanks with the help of words given in bracket after each sentence.

a)      When air is contaminated by ________ substances which have a ________ effect on both the ________ and ________, it is referred to as ________.

(air pollution, harmful, living, unwanted, non-living, pollutants).

b)      Many ________ are responsible for causing ________ pollution.

Petroleum ________ are a major source of ________ pollutants like ________ and ________.

(Sulphur dioxide, refineries, industries, nitrogen dioxide, gaseous, liquid, people, and air).

c)      While ________ your teeth, leaving the ________ running may waste several ________ of water.

(tap, litres, brushing, washing, drops)

d)      Water which is suitable for _________ is called ________ water.

(washing, bathing, drinking, potable, soft).

e)      Water which looks clean still has disease carrying ________and ________ impurities.

(Insects, microorganism, particles, dissolved, harmful).

(a) unwanted, harmful, living, non-living, air pollution.

(b) industries, air, refineries, gaseous, sulphur dioxide, nitrogen dioxide.

(c) brushing, tap, litres

(d) drinking, potable

(e) microorganisms, dissolved.

Match the items of Column A with those of Column B:

Column A	Column B
(a) sulphur dioxide	(i) damage ozone layer
(b) carbon dioxide	(ii) reduces oxygen carrying capacity of blood
(c) carbon monoxide	(iii) acid rain.
(d) chlorofluorocarbons	(iv) greenhouse gas

(a) $–$ (iii)      

(b) $–$ (iv)             

(c) $–$ (ii)            

(d) $–$ (i)

Find out the wrong statements and write them in their correct form:

a)      We can survive for some time without air but we cannot survive even for a few minutes without food.

b)      A brick kiln emits lot of smoke and other harmful gases causing air pollution.

c)      Carbon monoxide is produced by complete burning of fuels such as coal, petrol, and diesel.

d)      Chlorination is a commonly used chemical method for killing germs in water.

e)      Water which is suitable for drinking is called soft water.

Statements (b) and (d) are correct statements.

The correct form of statements (a), (c) and (e) are as follows-

a) We can survive for some time without food but we cannot survive even for a few minutes without air.

c) Carbon monoxide is produced by the incomplete burning of fuels such as coal, petrol, and diesel.

e) Water, which is suitable for drinking, is called potable water.

In the following statements, the underlined words are jumbled up.

Write them in the correct order.

a)      Air contains 78% ginroten and 21% gonexy.

b)      Vehicles produce high level of pollutants like carbon dioxide, nitrogen oxides,

nobrac moondexi and mosek.

c)      Carbon dioxide, thaneme, nitrous oxide and water vapour are known as

heengrouse sesga.

d)      Gangotri glacier in Himalaya has started melting because of lablog ringwam.

e)      Whenever harmful substances such as wagese, toxic chemicals, silt, etc. get mixed with water, the water becomes potdulle.

(a) Nitrogen, oxygen

(b) Carbon monoxide, smoke

(c) Methane, greenhouse gases

(d) Global warming

(e) Sewage, polluted

Long Answer Questions

What do CFCs stand for? Name some devices where CFCs are used. Why CFCs are considered as pollutants?

CFCs stand for chlorofluorocarbons. They are used in cooling systems, such as refrigerators, air conditioners, etc. They break ozone molecules in the ozone layer to oxygen, causing a hole in the layer. This hole permits the harmful UV rays reach lower atmosphere and affect living organisms.

Why is it advised that industries should switch over to cleaner fuels such as CNG and LPG in the Taj Mahal Zone in Agra?

Burning fossil fuels for industrial purposes release pollutants, such as sulphur dioxide and nitrogen dioxide into the air. These gases react with rain particles and water vapour in the air causing acid rain. Acid rain on marble structures, such as the Taj Mahal, leads to corroding and yellowing of marble and causing “marble cancer”. On the other hand, clean fuels such as, CNG and LPG, burns completely and do not release gases, such as sulphur dioxide and nitrogen dioxide.

It is said, “CO₂ contributes to global warming.” Explain.

Carbon dioxide, water vapour and methane are known as greenhouse gases. Among these, carbon dioxide acts as a shield in maintaining temperature of the earth. If the amount of carbon dioxide increases, it will trap more heat, leading to an increase in temperature globally, which will have an adverse effect on the earth.

We should plant trees and nurture the ones already present in the neighbourhood. Why?

Plants and trees prepare their own food by photosynthesis. During photosynthesis, plants and trees absorb carbon dioxide from the atmosphere and release oxygen into the air, which is very essential for all living organisms. This also reduces carbon dioxide content in the atmosphere and avoids global warming. Hence, it is crucial to plant trees and nurture the ones already present.

Explain the traditional way of purifying water to make it fit for drinking.

The traditional ways of purifying water are by filtration, by boiling and by adding chlorine tablets.

How can we reduce, reuse and recycle water?

Reduce, reuse and recycle, are the three methods to protect our environment and natural resources from pollution.

Reduce - Usage of water can be reduced by closing the taps when not in use. Use water from a bucket while bathing, instead of using a shower.

Reuse - Water used for washing vegetables, rice, etc. can be reused for gardening.

Recycle $–$ Dirty water can be recycled by purification and make it fit for consumption.

Read the paragraph and answer the questions following it.

Water is essential for life. Without water there would be no life. We usually take water as granted for its purity, but we must ensure the quality of water. Pollution of water originates from human activities. Through different paths, pollution reaches to ground water. Easily identified source or place of pollution is called as point source, e.g.$–$ municipal and industrial discharge pipes, where pollutants enter the water source. Non$–$point sources of pollution are those where a source of pollution cannot be easily identified, e.g.$–$ agricultural run-off, acid rain etc.

(i)     How do you classify the various sources of water pollution?

(ii)  What are the point sources of water pollution?

(iii)            Name any two non-point sources of water pollution?

(i)     The various sources of water pollution are point sources and non-point sources.

(ii)  The sources of water pollution which can be easily identified are called point sources. Discharge of domestic, municipal and industrial waste in water bodies are examples of point sources.

(iii)            Acid rain and agricultural run-off are examples of non-point sources.

Complete the crossword puzzle with the help of clues given below:

Across

1. Pollutant which was used in refrigerators and air conditioners. (18)

3. Produced on incomplete combustion. (6)

     6. This chemical protects crops from insects in the field (9)

Down

2. This layer protects us from harmful ultraviolet rays. (5)

4. It is essential for combustion of fuels. (14)

5. Disease which is caused by drinking contaminated water. (7)

      7. River which is famous in India (5)