8. Pollution
1. Following are some statements about
pollution. Which type of pollution do those express?
a. Fog seems to be appearing in Delhi during
day hours.
Ans: Air
pollution
b. Many times, vomiting and dysentery
occurs after eating ‘pani puri’.
Ans: Water
pollution
c. Problem of sneezing occurs sometimes during
visit to garden.
Ans: Air
pollution
d. Crop does not grow up in some areas.
Ans: Soil
pollution
e. People living in the busy squares
face the problems like short breathing and other respiratory problems.
Ans: Air
pollution
2. Read the passage and identify the sentences
expressing types of pollution.
Nilesh is a student of std. VIII and
lives in urban area. It takes about an hour to go to the school by bus. He
faces the heavy traffic of two wheelers, four wheelers, rickshaws, buses while
going to school. He is facing the problem of asthma since last few days.
Doctors recommended him to stay away from urban area. Since then, his mother
sent him to the village of his maternal uncle. Nilesh saw the heaps of garbage
at many places in village. Foul smell of human and animal wastes was present at
many places. Blackish water with foul smell was flowing in a stream. He
developed some abdominal disease within few days.
Ans:
Nilesh is a student of
std. VIII and lives in urban area. It takes about an hour to go to the
school by bus. He faces the heavy traffic of two wheelers, four wheelers,
rickshaws, buses (Air pollution) while going to school. He is facing the problem of asthma (Air pollution) since to stay away from urban area. Since then, his mother
sent him to the village of his maternal uncle. Nilesh saw the heaps of garbage
in many places in village. Foul smell of human and animal wastes (Air and soil pollution) was present at many places. Blackish water with foul smell (Water pollution) was flowing in a stream. He devleoped some abdominal disease (Water pollution) with in few days.
3. Match the pairs from ‘A’
and ‘B’ columns and explain the effect of pollution on human health.
Column ‘A’ Column ‘B’
1. Water a. Mental containing cobalt retardednes
2. Methane gas b. Paralysis.
3. Water containing c. Inflammation lead of lungs.
4. Sulphur dioxide d. Skin cancer
5. Nitrogen dioxide e. Irritation of eyes
Ans:
|
Column ‘A’ |
Column ‘B’ |
|
1. Water containing cobalt |
b. Paralysis. |
|
2. Methane gas |
d. Skin cancer |
|
3. Water containing lead |
a. Mental containing cobalt retardednes |
|
4. Sulphur dioxide |
e. Irritation of eyes |
|
5. Nitrogen dioxide |
c. Inflammation lead of lungs. |
4. True or false
a. Water does not get polluted by
washing the cloths in running water of river.
Ans : False
b. More the use of electric appliances, more
will be the pollution.
Ans: True
5. Answer the following.
a. What is pollution?
Ans: Pollution
is any undesirable change that takes place in the environment which is harmful
to both living and non-living things.
b. What are pollutants?
Ans: Pollutants
are the harmful chemicals and substances that cause pollution. For
example, nitrogen oxides, sulphur oxides, carbon monoxide, pesticides etc.
c. What is acid rain?
Ans: . Gases such as sulphur
dioxide, sulphur trioxide and nitrogen dioxide, when present in air, combine
with the water droplets present in the atmosphere to form acid droplets. These
droplets remain suspended in air and fall down on the earth along with rain,
thereby making the rain acidic. Such rain is called acid rain.
d. What is green house effect?
Ans: The
increase in the average temperature of the earth’s surface due to the increase
in concentration of greenhouse gases such as carbon dioxide, methane, etc. is
called greenhouse effect.
e. Which are visible pollutants known
to you?
Ans: Pollutants
which are visible to our naked eyes are called visible pollutants. For example,
sewage, plant and animal wastes, pesticides, plastic, sand etc.
f.
Which are invisible pollutants?
Ans: Invisible
pollutants are pollutants which are not visible to our naked eyes. For example,
fungi, viruses, bacteria, gases like carbon monoxide, nitrogen dioxide etc.
6. Answer the following
a.
Give two examples of each of water, soil and air pollution from your
residential area.
Ans: Air pollution:
1.
New buildings are constructed. Old
structures are demolished. This is creating lots of dust pollution. The air is
full of particulate matter.
2.
The number of vehicles on the road
has tremendously increased. This causes smoky environment.
Water pollution:
1.
The sea shows lots of floating
plastic and decaying flowers, etc. When beaches are visited it is a common
sight.
2.
Many fishes are seen dying in great
numbers and are washed off to the shore.
Soil pollution :
1.
Everywhere garbage heaps are seen. In
that plastic bags, needles, old medicine vials and cartons are seen in
abundance.
2.
The sludge brought by rainwater is
spread everywhere and that causes stink.
b. How does the pollution occur due to
vehicles? Give the names of vehicles causing least pollution.
Ans :
Most of the vehicles are run on fossil fuels
like petrol and diesel. These fossil fuels are burnt in vehicles to produce
energy which results in the production of smoke. This smoke conatins harmful
gases like carbon monoxide, hydrogen, nitrogen oxide, particulate matter,
ammonia and sulphur dioxide.
There are various other kinds of vehicles which
cause least or no pollution at all, for example. bicycle, vehicles run on CNG,
electric cars, metro etc.
c. What are natural reasons for water
pollution?
Ans: The
natural reasons of water pollution are :
- Presence of aquatic weeds which depletes the oxygen content of
water bodies.
- Excessive algal growth.
- Mud and sludge which are added to water bodies due to river
currents and their diversions.
- Growth of microbes like bacteria and fungi on dead and decaying
matter present in water bodies.
d. Suggest four preventive measures for air
pollution.
Ans: Some of the measures that can be taken to prevent
air pollution are as follows:
(i) Use of clean fuels such as CNG,
LPG and unleaded petrol in public and private transport.
(ii) Use of renewable sources of energy such as
solar, wind, and hydel energy.
(iii) Planting more and more trees to prevent
pollution.
(iv) Preventing burning of dry leaves and using
them in composting.
e. Explain relation between green house effect
and global warming.
Ans: Greenhouse
gases such as CO2, methane, etc. are gases that absorb the heat of
the Sun and the Earth and emit it back to the Earth’s surface. Thus, these
gases prevent a part of the heat rays from escaping into the atmosphere. This
cycle is repeated several times to maintain the Earth’s temperature to an
optimum temperature of 15°C. Therefore, upto a normal level, greenhouse gases
help in maintaining the temperature on the Earth.
However, the concentration of these gases has
increased because of increased industrialization, which has lead to the heating
up of the Earth’s surface. As a result, the overall temperature of the Earth
has increased, resulting in climatic changes. During the last century, the
temperature of the Earth has increased by 0.6°C. This has lead to global
warming.
The greenhouse effect can be controlled by reducing
the use of fossil fuels. Fossil fuels produce greenhouse gases on burning.
f. Construct two slogans each on air, water
and soil pollution.
Ans: Air pollution:
1.
Be a part of the solution and not part of
pollution.
2.
Show your care, clean your air.
Water pollution:
1.
Water, water everywhere, Not a drop to drink. The
pollution is making all the water stink.
2.
Save the fish and the little turtle. Don’t throw
plastic or it will encircle.
Soil Pollution:
1.
Don’t be mean, keep environment clean.
2.
Let’s keep land clean, together only we can win.
7.
Classify the following pollutants into natural and manmade categories.
Sewage, dust, pollen grains, chemical
fertilizers, vehicular smoke, algae, pesticides, waste of animals and birds.
|
Pollutant |
Category |
|
Sewage |
Man
made |
|
Dust |
Natural |
|
Pollen grains |
Natural |
|
Chemical fertilizers |
Man
made |
|
Vehicular smoke |
Man
made |
|
Algae |
Natural |
|
Pesticides |
Man
made |
|
Waste of animal and plants |
Natural |