WBBSE Class 10 Life Science Solutions Chapter 5B Environmental Pollution

Detailed explanations in West Bengal Board Class 10 Life Science Book Solutions Chapter 5B Environmental Pollution offer valuable context and analysis.

WBBSE Class 10 Life Science Chapter 5B Question Answer – Environmental Pollution

Short Answer Type Questions : 2 Marks

Question 1.
Why does the concentration of harmful substances increase significantly in certain location?
Answer:
Atmospheric diffusion of air is minimum at elevation of 3000 metres above earth’s surface. Many pollutants do not rise above 600 metre. Mixing and dilution of pollutants are often hampered by natural and artificial barriers. Therefore, concentration of harmful substances often becomes high in certain locations.

Question 2.
What is Acid rain?
Answer:
Oxidation of sulphur in the fossil fuels mainly produces sulphur dioxide and sulphur trioxide, which are harmful. These gases react with water to form sulphuric or sulphurous acids. The acids, when precipitated as rain or snow, create acid rain or acid precipitation.

Question 3.
How has the average temperature of the earth remained constant?
Answer:
The average temperature of the earth has remained fairly constant because there is a balance between the amount of energy received and that reflected from the earth back into space.

Question 4.
Why does the concentration of pollutants become high in certain location?
Answer:
Increase in the concentration of pollutants takes place because mixing a dilution of pollutants is hampered by artificial barriers, i.e. diffusion of pollutants above 300 metres above earth’s surface is minimal. Many pollutants do not rise above 600 metres.

Question 5.
What are particulate pollutants?
Answer:
Pollutants in the form of solid or liquid particles are known as particulate pollutants.

Question 6.
Name the major pollutants emitted by motile commercial source.
Answer:
The major pollutants emitted by motile commercial sources are carbon monoxide (77.2%), nitrogen oxides (7.7%), hydrocarbons (13.7%) and a small fraction of lead products.

Question 7.
What is the effect of sulphur dioxide on human?
Answer:
Sulphur dioxide is highly soluble in water. It enters soft tissues and causes dryness of the mouth, scratchy throat and irritation of the eyes.

Question 8.
Name the respiratory problems caused by polluted air?
Answer:

1. Bronchitis
2. Emphysema
3. Lung cancer, especially in children.

Question 9.
Name two ways by which air pollutian is controlled at the source.
Answer:
(i) By separating the pollutants from the harmless gases, and (ii) By converting the pollutants into innocuous products.

Question 10.
What is BOD?
Answer:
Biochemical Oxygen Demand (BOD) is the amount of oxygen taken up by micro-organisms in the water.
BOD is measured by keeping a sample of water containing known amounts of oxygen for five days at 20° C in the dark. At the end of five days the oxygen content is measured again.
A high level of BOD indicates intense level of microbial pollution, signifying the presence of high level of organic pollutants.

Long Answer Type Questions : 5 Marks

Question 1.
What do you mean by soil pollution?
Answer:
Soil pollution :

• Soil pollution, also called land pollution is addition or removal of nutrients which reduces the productivity of soil.
• The substances which are responsible for the reduction of soil productivity are called as soil pollutants.
• Soil pollutants alter the basic composition of the soil that may kill important soil organisms.
• There are two types of soil pollution-positive and negative soil pollution.
• When there is addition of undesirable substance in the soil then it is called as positive pollution.
• When there is reduction of soil fertility due to loss of its top layer, it is called as negative pollution.
• Negative pollution is also sometimes called third pollution or landscape pollution in which fertile land is converted into barren areas by addition of solid wastes like leather goods, spoiled food items etc.

• Pesticides, fertilizers, chemicals and radioactive wastes are the main sources of soil pollution.
• Excessive use of fertilizers causes soil deterioration through decrease of natural mircoflora. Leaching down causes pollution of underground water (third poison).
• Salts entering crop plants in excess may prove harmful.
• For example, nitrate rich leaves, fruits and water produce nitrite in alimentary canal that enters blood, combines with haemoglobin forming met-haemoglobin and reducing oxygen transport. It may prove fatal in infants.
• Soild wastes from municipalities and industries are often dumped temporarily over land. During rains heavy metals and toxic chemicals are washed down into soil and pollute the same.
• Quality of land also deteriorate due to deforestation, desertification, water logging and flooding.

Question 2.
What do you mean by pesticides?
Answer:
Pesticides include insecticides, fungicides, algicides, rodenticides and weedicides. Along with target organism they harm nontarget organism as well. This destroys the ecosystem of the soil.
Pesticides are of following types :

• Organochlorines/Chlorinated Hydrocarbons : DDT, BHC, aldrin, dieldrin and endrin. They are persistent and show biomagnification and thus prove harmful to higher trophic level organisms.
• Organo-pesticides : Degradable but toxic to workers, e.g. malathion, parathion, carbamates.
• Inorganic pesticides : They contain arsenic and sulphur and are persistent. Hence their use is highly restricted.
• Weedicides : They are persistent and harmful.

Question 3.
What do you mean by solid wastes?
Answer:
Solid wastes :
Solid wastes are discarded or left over solid materials. The terms rubbish and trash are often used interchangeably for solid waste materials. The various sources of solid wastes are municipal wastes, industrial wastes, mining wastes, hazardous wastes, defunct ships and electronic wastes.

Municipal wastes are solid wastes from homes, shops, offices, schools, street and road sweepings which are collected and disposed off by municipalities. The major components are waste paper, textiles, leather, metals, glass, plastic and polythene, food wastes etc.

Industrial wastes include scrap, effluents, sludge and flyash. Flyash is fall out from industrial emissions especially thermal plants which is often mixed with smoke. It consists of oxides of silica, aluminium and iron alongwith small quantities of heavy metals.

Mining wastes include mine dust, rock tailings, slack and slag. Toxic metals and chemicals present in the mining wastes destroy vegetation and produce many deformities in animals and human beings.

Opencast mining is a process where the surface of the earth is dug open to bring out the underground mineral deposits completely devastating the topsoil and contaminates the area with toxic metals and chemicals.

Hazardous solid wastes are generated by industries producing pesticides, rubber, dyes, chemicals, paper and metals. They are not only highly toxic to humans and other organisms but are also corrosive and highly inflammable.

Hospital wastes are full of hazardous materials like infected organic wastes, pathogens, pathogen carriers, harmful chemicals, needles, syringes, vials etc. along with some disinfectants.

Electronic wastes are irreparable computers, mobiles and other electronic goods often called e-wastes. Electronic wastes are generally sent to developing countries like India, China and Pakistan for extraction of metals through recycling.

Question 4.
Write the control of soil pollution and solid wastes.
Answer:
Control of soil pollution :

• Soil pollution can be checked by improving the disposal wastes, appropriate use of chemical fertilizers and use of biological pest.control.
• The most important measure to check land degradation is restoration of forest, crop rotation, improved drainage etc.

Control of solid wastes :

It involves collection and categorisation of wastes, transport to disposal site and disposal of waste. Disposal of waste consists of recovery and recycling, source reduction, burning and dumping.
The articles which can be recovered and recycled are tins, cans and other metal wastes, glass, plastic, polyethylene, rags, paper and cardboard.
Metal waste can be melted and purified. Broken glass is used similarly to form new glass.
Waste polyethylene is melted and recast to form new polyethylene.
In source reduction garbage and other organic wastes are taken out of urban areas and used for formation of compost, biogas and manure.
On small scale vermiculture is practised to form manure and compost.
All types of organic wastes of a town are used to prepare a manure called compost. In composting the sludge obtained after primary treatment of sewage alongwith other wastes are allowed to decompose in an open space. In 4 6 months compost is ready for use as a manure.
Cowdung and other organic wastes of farm houses can now be profitably placed in gobar gas plants which not only enrich manure but also provide gas for domestic use.
Burning is combustion of solid waste containing organic compounds in open places. It, however, produces offensive odours and air pollutants. Better methods are incineration and pyrolysis.
Incineration : It is controlled aerobic combustion of wastes inside chambers at temperature of 900-1300° C.
Pyrolysis : It is combustion inside chambers in the absence of oxygen at a temperature of 1650° C. It does not yield pollutant.
Dumping is piling of waste on selected low lying land. It is of two types, open and sanitary.
In open dumping (open landfill), waste is accumulated on uncovered low lying area and it is periodically burnt or compressed at intervals to reduce its bulk.
In sanitary dumping (sanitary landfill), the waste is pulverised, compacted or covered over by a layer of earth.

Question 5.
What do you mean by noise pollution with their sources, effect and control measures?
Answer:
Noise Pollution :
Unpleasent loud sound is called as noise (also called slow killer) and disturbing level of noise is known as noise pollution.
Annoying noise from industries, transport vehicles, agricultural machines, defence equipments, domestic gadgets, music systems, public address systems and demonstrations are various causes of noise pollution.
Noise pollution is measured in decibels.
Generally sound above 80 dB is termed as noise.
A sound more than 115 dB is harmful to the ears.
Moderate conversation has a noise value of 60 dB; scooter, buses, trucks etc. create noise of about 90 dB; jets of about 150 dB and rockets of 180 dB.
A decibel value above tolerable limit of noise is about 140 dB.
Sources of noise pollution

Main sources of noise pollution are:
Various industries such as textile mills, printing presses, engineering establishments.
Agricultural machines like tractors, harvesters, tubewells etc.
Defence equipment such as tanks, artillery, rocket launching, shooting practices, explosions.
Entertaining equipment like radios, record players, television sets.
Domestic gadgets such as desert coolers, air conditioners, vacuum cleaners, exhaust fans, mixers, pressure cooker.
Public address systems like loud speakers.
Transport vehicles like scooters, motor-cycles, ear, buses, trucks, trains, jet planes.
Dynamite blasting.
Crackers used at occasions like marriages and festivals.
Bull dozing, stone crushing, construction work etc.
Effects of noise pollution
Auditory effects
Auditory fatigue appears in the 90 dB region and greatest at 4000 Hz. It may be associated with side effects such as whistling and buzzing in the ears.
Deafness or hearing loss is the most serious pathological effect.
Further, it has been found that prolonged noise at 95 dB will produce deafness, nervous tension and rise in blood pressure.
A regular exposure to sound of 80 dB reduces hearing by 15 dB in 10 years.
Noise becomes uncomfortable above 100 dB.
Non-auditory effects
Noise interferes with speech communication. In everyday life the frequencies causing most disturbance to speech communication lie in the 300-500 Hz range. Such frequencies are commonly present in noise produced by road and air traffic.

The first effect of noise pollution is anxiety and stress reactions. Annoyance is primarily a psychological response. Neurotic people are more sensitive to noise than balanced people.

Work men exposed to higher intensities of noise in occupational capacities, were often irritated, short tempered and impatient and more likely to resort to agitation and disrupt production.
A number of temporary physiological changes occur in the human body as a direct result of noise exposure. These are a rise in blood pressure, a rise in intracranial pressure, .an increase in heartrate and breathing and an increase in sweating.
Efficiency to work decreases by noise pollution. Noise stimulates the secretion of adrenaline which increases irritability, nervousness, neuromuscular tension and feeling of fatigue, so decreasing the working efficiency.
Noise causes vasoconstriction which decreases the blood flow.
Control of noise pollution
For controlling the noise pollution, several methods have been suggested.
In metropolitan areas green belt vegetation and open space in general may have a great value in noise control as in air purification.
Green muffler scheme involves the growing green plants along roadsides to reduce noise pollution.
The enclosure of machinery with sound absorbing materials is an example of the industrial noise reduction pattern already practised by industries in advanced countries. Protection to workers can be provided through wearing devices such as a ear-plugs.
Specific legislation and regulations should be proposed for designing and operation of machines, vibrations control, sound-proof cabins and sound-absorbing materials.

Question 6.
What do you mean by ozone layer depletion and its effects?
Answer:
Ozone layer depletion
Stratosphere have a thick layer of ozone called ozonosphere which protects life on earth from harmful effects of UV radiations. Thickness of ozone is measured in Dobson unit.
Ozone in the Earth’s atmosphere is generally created by ultraviolet light striking oxygen molecules, which consist of two oxygen atoms (O₂), creating two single oxygen atoms, known as atomic oxygen. The atomic oxygen then combines with a molecule of O₂ to create ozone, O₃.
In stratosphere ozone is formed and photodissociated. It dissipates the energy of UV radiations.

Ozone absorbs most of the ultraviolet radiation, so it shields earth against biologically harmful solar radiations.
Ozone depletion refers to the phenomenon of reduction in the amount of ozone in the stratosphere. The depletion of O₃ layer by human activities may have serious implications and this has become a subject of much concern over the last few years.
Depletion in the concentration of ozone over a restricted area as over Antarctica is called ozone hole. An ozone hole was discovered over Antarctica by Farman et al, 1985 who also coined the term.
Spring time depletion of ozone is due to action of sunlight over pollutants which release chemicals (e.g., chlorine) that destroy ozone.

Thinning of ozone shield will increase the amount of UV-B radiation reaching the earth which will result in 2,50,000 more persons catching skin cancer and 5,00,000 more persons becoming blind.
Ozone depleting substances (ODS) are substances which react with ozone present in the stratosphere and destroy the same.
The ozone layer is destroyed by aerosols. Aerosols are certain chemicals released into the air with force in the form of mist or vapour.
Major aerosol pollutant present in jet plane emissions is fluorocarbon.
Besides chloroflourocarbons or CFCs (CCl₂ F₂\right. and CCl₃ F; used as coolants in air conditioners and refrigerators, cleaning solvents, aerosol propellants and foam insulation), nitrogen oxides (coming from fertilisers) and hydrocarbons are also responsible for O₃ depletion.

CFC produces active chlorine in the presence of UV radiation. These destroy ozone, converting it into oxygen. The reactions were discovered by Molina and Rowland (1974, Noble Prize, 1995 along with Crutzen). Chlorine action over ozone is chainamictics.

Effects of ozone depletion
Ultraviolet radiations are of three types UV-C (100 280 nm), UV-B (280 320 nm) and UV-A (320-390 nm).
The intermediate or UV-B are harmful as well as cayable of deeg genetration.
Thinning of ozone layer increases the amount of UV-B radiations reaching the earth.
Researches show that surface UV-B radiation inhibits photosynthesis in Antarctic phytoplanktons. This, in turn, can affect the whole food chain of organisms that depend on phytoplankton. Elevated levels of UV-B radiation affect photosynthesis, as well as damage nucleic acid in living organisms.

The various other important effects of ozone depletion are :
Cornea absorbs UV-B radiations and becomes inflamed. The disorder is called “snow blindness” cataract. It leads to diminishing of eye sight, photoburning and later permanent damage to cornea that results in actual cataract.
UV-B radiations damage skin cells, cause ageing of skin and skin cancer.
Damage of nucleic acids will increase resulting in higher number of mutatinosa.
UV radiations inhibit photosynthesis by affecting photosynthetic machinery.
Decreased photosynthetic activity will increase CO₂ concentration of the atmosphere resulting in global warming.
Both marine and terrestrial food chains will be disturbed.

Question 7.
What do you mean by greenhouse effect? Write its effect.
Answer:
Greenhouse effect :
The atmospheric greenhouse gases forms a blanket like covering around the earth. It controls the escape of heat from the earth’s surface to outer space and keeps it warm and hostile. This phenomenon is known as greenhouse effect.
It is actually a warming effect found in greenhouse by allowing solar radiations to pass in but preventing long wave heat radiations to pass out due to glass panels, water vapours and carbon dioxide. Because of it greenhouses are used for growing tropical plants in temperate areas.
The capacity of atmosphere to keep the Earth warm depends on the amount of greenhouse gases the gases which are transparent to solar radiation but retain and partially reflect back long wave heat radiations.
Greenhouse gases radiate a part of this solar energy back to the earth. The phenomenon is called greenhouse flux. Because of greenhouse flux, the mean annual temperature of earth is 15° C.
Recently the concentration of greenhouse gases has started rising resulting in enhanced greenhouse effect that is resulting in increasing the mean global temperature. It is called global warming.
The various greenhouse gases are CO₂ (warming effect 60% ), CH₄ (effect 20%), chlorofluorocarbons or CFCs (14%) and nitrous oxide (N₂ O 6%). Others of minor significance are water vapour and ozone.

Effects of green house gases
CO₂ fertilization : Increase in CO₂ concentration increases the rate of photosynthesis especially in C₃ plants. Amount of stomatal conductance will decrease resulting in lower rate of transpiration. There will be greater root growth, more mycorrhizal development and increase in N₂ fixation in root nodules. So that plants will grow more successfully in regions of water scarcity and nutrient poor soils. However, these beneficial effect will be nullified by negative effects of global warming.
Global warming : It is believed that increase in concentration of greenhouse gases has resulted in rise of atmospheric temperature. Rise in temperature will be slight in tropics, moderate in middle latitudes and maximum in polar regions (World Climate Programme, WCP, 1988).

Global warming has many fold effects as :
Effect on weather and climate: There is increase in average temperature by 1.4-5.8° centigrade by the year 2100 . Warming of atmosphere increases its moisture containing capacity. All these are responsible for change in precipitation pattern. This climatic change is harmful for human health.

Sea level change : The global warming is responsible for increase in sea level and melting of-glaciers and Greenland ice sheets.
Effects on range of species distribution : Due to increase in global warming, many species are expected to shift poleward or towards high elevation in mountain regions.

Food production : Increase in temperature causes extensive growth of weeds which ultimately decrease crop production.
Some strategies should be followed to deal with global warming:
Vegetation cover should be increased for photosynthetic utilization of carbon dioxide.
Chlorofluorocarbon should be replaced with some other substitute having little effect on global warming.
Reducing the use of nitrogen fertilizers to reduce nitrous oxide emission.
Minimizing the use of fossil fuel to reduce the greenhouse gas emission.

Question 8.
What do you mean by air pollution?
Answer:
Air Pollution

1. Oxides of Carbon : Carbon monoxide, Carbon dioxide
2. Oxides of Nitrogen : Nitrogen oxide and Nitrogen dioxide
3. Oxides of Sulphur : Sulphur dioxide and Sulphur trioxide.
4. Photochemical oxidants : Ozone, PAN (Peroxyacyl nitrate) aldehydes and other organic compounds produced by photochemical reactions between primary pollutants.
5. Hydrocarbons : Products of incomplete combustion of automobile fuel.
6. Particulate Matter : Fine solid and liquid particles, like flyash and soot from burning of coal; dust particles from industries.
7. Chemical released in vapour form as fluorocarbons, chloro-fluoromethanes.

Sources :

1. Effect-on plants : Like Chlorosis, necrosis, bleaching, premature fall of leaves, reducing photosynthetic capacity etc. leading to the damage of the crops.
2. Effects on animals and man : Like dryness of skin, congestion of respiratory tract, reduction in oxygen transport, damage to nervous system; chromosomal aberrations and cancer.
3. Climatic changes: Like Green House effect leading to global warming. Depletion of ozone layer and consequent increase in ultraviolet radiations which can cause mutations and cancer.
4. Aesthetic loss: Like spoiling the beauty of nature.

Effects :

1. Stationery combustion sources
2. Mobile combustion sources
3. Industrial processes and
4. Other sources

Question 9.
What are the sources and effects of Water Pollution?
Answer:

Sources :

1. Community waste water : as discharges from homes and commercial and industrial establishments connected to municipal sewage system.
2. Industrial waste : as chemical wastes which are discharged into rivers or streams.
3. Agricultural sources: addition of fertilisers to crops results in water pollution in water-bodies.
4. Marine pollution : navigational discharges of oil grease and petroleum products, detergents, sewage and garbage including radioactive wastes.

Effects :
The main effects of water pollution are:

1. Compounds of mercury, arsenic and lead are poisonous and they may affect the waste treatment plant.
2. Organic sulphur compounds interfere with nitrification.
3. Inorganic nitrates and phosphates stimulate excessive plant growth in lakes and reservoirs.
4. The organochlorines from pesticides are highly persistent and pass through food chains. They mainly accumulate in the nervous tissue and affect the nervous system.
5. The broad spectrum pesticides used currently cause mass destruction of aquatic life through their accidental release or excessive use.
6. Due to the presence of very fine suspended matter, water becomes unclear, unfit for drinking and industrial use.
7. Presence of free chlorine, phenol, hydrogen, ammonia, algae and microorganisms make it bad in taste and odour, and cause infection too.
8. Formation of foam due to presence of soaps, detergents and alkalies.

Question 10.
What are the effects of radioactive pollution?
Answer:
Effects of radioactive pollution
The effect of radioactive pollutants depends on :
Strength of radiations
Rate of diffusion and deposition of the pollutants
The length of time for which the tissue is exposed to radiation
Half-life of pollutants. Environmental factors (wind, temperature, rainfall) also influence their effects.
Radioactive pollution affects all the organisms including humans. It causes cancer, mutations and even death in humans and animals.
On the basis of their action on cells, radiations are divided into two categories non-ionising radiations and ionising radiations.
Non ionising radiation refers to any type of electromagnetic radiation, that does not carry enough energy per quantum to ionize atoms or molecules.
Near ultra-violet, visible light, infrared, microwave, radio waves are all examples of non-ionising radiations.
Ionising radiation consists of electromagnetic waves that are energetic enough to detach electrons from atoms or molecules ionising them.
Ionising radiations include ultra-violet rays. X-rays, cosmic rays and atomic radiations which damage the living cells by ionisation (shifting the electrons from one to other bio-molecule). Ultra-violet rays (100-300 nm) are known to cause sunburn, snow blindness, inactivation of organic bio-molecules, formation of thymine-dimer in DNA and skin cancer.
Strontium-90 behaves like calcium in biogeochemical cycling of materials in ecosystem. It accumulates in the bones to cause bone cancer and tissue degeneration in a number of organs.
Iodine-131 damages WBCs, bone marrow, spleen, lymph nodes, skin cancer, sterility and defective eye sight.
Radioactive iodine may also cause cancer of thyroid glands.
Cesium-137 brings about nervous, muscular and genetic changes.
Uranium causes skin cancers and tumors in the miners.
Actively growing and dividing cells like those of stratum germinativum, intestinal lining, bone marrow; gonads and embryo (with all cells rapidly growing and dividing) are more susceptible to ionising radiations.
A foetus in the womb may be killed by radiation which has little effect on the mother. Cancer cells are destroyed by radiation as they are of actively growing type. It has been reported that the pine seedlings are destroyed by radiations whereas the trees flourish.
Less active and non-dividing cells like osteocytes of bones, muscles fibres and neurons are not easily damaged by radiation.

Multiple Choice Questions : 1 Mark

Question 1.
Pollution is an undesirable change in physical, chemical and biological properties of
(a) Air
(b) Soil
(c) Water
(d) All of these
Answer:
(d) All of these

Question 2.
An indicator of air pollution is
(a) Lichens
(b) Mosses
(c) Ferns
(d) Pines
Answer:
(a) Lichens

Question 3.
Which of the following is the chief source of air pollution?
(a) Automobiles
(b) Burning coal
(c) Industries
(d) All of these
Answer:
(d) All of these

Question 4.
Carbon dioxide, nitrates and phosphates are
(a) Producers
(b) Decomposers
(c) Biotic substances
(d) Abiotic substances
Answer:
(c) Biotic substances

Question 5.
The hazardous metal pollutant from automobiles which hampers haemoglobin formation is
(a) NO₂
(b) SO₂
(c) Lead
(d) Mercury
Answer:
(c) Lead

Question 6.
Which of the following is an important atmospheric pollutant?
(a) Carbon monoxide
(b) Carbon dioxide
(c) Sulphur dioxide
(d) Hydrocarbon
Answer:
(a) Carbon monoxide

Question 7.
Which of the following is the least harmful pollutant?
(a) CO
(b) SO₂
(c) NO₂
(d) CO₂
Answer:
(d) CO₂

Question 8.
The presence of ozone (O₃) in the atmosphere of our earth
(a) Helps in checking the penetration of ultra-violet rays on the earth
(b) Is advantageous since it supplies O₂ for people travelling in jets
(c) Hinders higher rate of photosynthesis
(d) Both (b) and (c)
Answer:
(a) Helps in checking the penetration of ultra-violet rays on the earth

Question 9.
If BOD of a river is high, it means the river
(a) Is not polluted
(b) Is very polluted
(c) Does not have green plants
(d) Gets least amount of light
Answer:
(b) Is very polluted

Question 10.
The disease which is not caused by polluted water is
(a) Dysentery
(b) Jaundice
(c) Tuberculosis
(d) Typhoid
Answer:
(d) Typhoid

Question 11.
Which of the following is the index of pollution in a polluted lake?
(a) Algae
(b) Daphnia
(c) Frog
(d) Aquatic weeds
Answer:
(b) Daphnia

Question 12.
A powerful eye irritant present in smog is
(a) Nitric acid
(b) Peroxyacetyl nitrate
(c) Sulphur dioxide
(d) Ozone
Answer:
(b) Peroxyacetyl nitrate

Question 13.
The atmosphere pollutant which is not produced by the exhaust of motor vehicle in Delhi is
(a) Carbon monoxide
(b) Sulphur dioxide
(c) Flyash
(d) Hydrocarbon gases
Answer:
(c) Flyash

Question 14.
In Bombay, the major air pollutant is
(a) Carbon monoxide
(b) Hydrocarbons
(c) Algal spores
(d) All of these
Answer:
(a) Carbon monoxide

Question 15.
The most polluted city in the world is
(a) Tokyo
(b) New York
(c) Calcutta
(d) Mexico
Answer:
(d) Mexico

Question 16.
Which one is the major source of pollution in metropolitan cities?
(a) Pesticides
(b) Automobiles
(c) Industries
(d) Radioactive substances
Answer:
(c) Industries

Question 17.
The pollutant which directly affects the nervous system is
(a) DDT
(b) Aldrin
(c) Lindane
(d) Organic phosphate
Answer:
(d) Organic phosphate

Question 18.
Some effect of SO₂ and its transformation products on plants includes
(a) Plasmolysis
(b) Chlorophyll destruction
(c) Golgi body destruction
(d) All of these
Answer:
(b) Chlorophyll destruction

Question 19.
In the atmosphere, the accumulation of which gas does not lead to green house effect?
(a) N₂
(b) NO₂
(c) CO
(d) All of these
Answer:
(d) All of these

Question 20.
The environmental planning organisation is
(a) ICAR
(b) NEERI
(c) NCL
(d) NPO
Answer:
(b) NEERI

Question 21.
Contamination of radioactive materials are dangerous because it causes
(a) Biological magnification
(b) Gene mutation
(c) Photochemical smog
(d) Ozone destruction
Answer:
(b) Gene mutation

Question 22.
Which of the following is not an ionising radiation ?
(a) Alpha rays
(b) Beta rays
(c) UV rays
(d) Infrared
Answer:
(d) Infrared

Question 23.
The pollutant that is degradable but toxic to workers
(a) Melathion
(b) DDT
(c) Aldrin
(d) Lindane
Answer:
(a) Melathion

Question 24.
The Environment (Protection) Act to protect and improve the quality of environment (air, water and soil) was passed by the Government of India in the year
(a) 1971
(b) 1974
(c) 1981
(d) 1986
Answer:
(d) 1986

Question 25.
Which one of the following occurs in radioactive fallout and behaves like calcium in biogeochemical cycling of material in ecosystem?
(a) Strontium-30
(b) Cobalt-60
(c) Cesium-137
(d) None of these.
Answer:
(a) Strontium-30

Question 26.
Ozone prevents the entry of
(a) Infrared rays
(b) Visible rays
(c) UV rays
(d) X-rays
Answer:
(c) UV rays

Question 27.
Ozone layer of upper atmosphere is being destroyed by
(a) SO₂
(b) Chlorofluorocarbons (CFCs)
(c) CO₂
(d) Both (a) and (b)
Answer:
(b) Chlorofluorocarbons (CFCs)

Question 28.
Green muffler is used against which type of pollution?
(a) Air
(b) Soil
(c) Water
(d) Noise
Answer:
(d) Noise

Question 29.
Ozone hole refers to
(a) Reduction in the thickness of ozone layer in stratosphere
(b) Reduction in ozone layer in stratosphere
(c) Hole in the ozone layer
(d) Increased concentration of ozone
Answer:
(a) Reduction in the thickness of ozone layer in stratosphere

Question 30.
UV-B radiation from sun causes which of the following disorder of eyes?
(a) Cataract
(b) Glaucoma
(c) Dilation of pupil
(d) Some defect in retina
Answer:
(a) Cataract

Question 31.
Sound above is termed as noise
(a) 95 dB
(b) 80 dB
(c) 115 dB
(d) 140 dB
Answer:
(b) 80 dB

Question 32.
Flyash is a
(a) Mining waste
(b) Hospital waste
(c) Industrial waste
(d) Municipal waste
Answer:
(c) Industrial waste

Question 33.
Green house effect is warming due to
(a) Infrared rays reaching earth
(b) Moisture layer in atmosphere
(c) Increase in temperature due to increase in carbon dioxide concentration of atmosphere
(d) Ozone layer of atmosphere.
Answer:
(c) Increase in temperature due to increase in carbon dioxide concentration of atmosphere

Question 34.
ODS means
(a) Ozone developing substances
(b) Ozone depleting substances
(c) Ozone data source
(d) Office data secrecy
Answer:
(b) Ozone depleting substances

Question 35.
Montreal Protocol was signed in
(a) 1978
(b) 1987
(c) 1991
(d) 1993
Answer:
(b) 1987

Question 36.
Kyoto conference is connected with
(a) Limiting production of CO₂
(b) Developing alternatives to ODS
(c) Both (a) and (b)
(d) Reduction in use of energy
Answer:
(c) Both (a) and (b)

Question 37.
CFCs split up in stratosphere to release chlorine by the action of
(a) UV-A
(b) UV-B
(c) UV-C
(d) All of these.
Answer:
(c) UV-C

Question 38.
Thermal pollution causes
(a) Increase in metabolic activities of aquatic organisms
(b) Decreases in DO contents of water
(c) Oxygenation in water
(d) Both (a) and (b)
Answer:
(d) Both (a) and (b)

Question 39.
Greenhouse gases are
(a) Absorbers of long-wave heat radiations from earth
(b) Transparent to both solar radiations and long-wave radiations from earth
(c) Absorbers of solar radiations for warming the atmosphere of earth
(d) Transparent to emissions from earth for passage into outer space.
Answer:
(a) Absorbers of long-wave heat radiations from earth

Question 40.
Climate of the world is threatened by
(a) Increasing concentration of atmospheric oxygen
(b) Decreasing amount of atmospheric oxygen
(c) Increasing amount of atmospheric carbon dioxide
(d) Decreasing amount of atmospheric carbon dioxide.
Answer:
(c) Increasing amount of atmospheric carbon dioxide

Question 41.
The first effect of noise is
(a) Constriction of blood vessels
(b) Anxiety and stress reactions
(c) Increased heart beat
(d) Digestive spasm
Answer:
(b) Anxiety and stress reactions

Question 42.
Ban of DOT and start of Ganga action plan occurred in the year
(a) 1982 and 1985
(b) 1985 and 1986
(c) both in 1982
(d) both in 1985
Answer:
(b) 1985 and 1986

Question 43.
World environment day is
(a) 5th June
(b) 14th November
(c) 2nd October
(d) 28th February
Answer:
(a) 5th June

Question 44.
The worst environmental hazards created accidents in nuclear power plant and MIC gas tragedy respectively in
(a) Russia in 1990 and Bhopal in 1996
(b) Ukrain in 1986 and Bhopal in 1984
(c) Bhopal in 1994 and Russia in 1999
(d) Ukrain in 1988 and USA in 1984
Answer:
(b) Ukrain in 1986 and Bhopal in 1984

Question 45.
The ‘Earth Summit’ was held at
(a) Geneva
(b) New Delhi
(c) Sydney
(d) Rio-de-janeiro
Answer:
(d) Rio-de-janeiro

Fill in the blanks with suitable words

1. The agents that pollute the environment are called _______
2. ______ percent of atmospheric pollution is caused due to activities of modern man.
3. ______ pollutants may be solid or liquid particles.
4. Pollutants are evaluated on the basis of the amount and their relative _______
5. Ozone and nitrous compounds are _______ pollutants.
6. Oxidation of sulphur in the fossil fuels produces harmful gases ______ and _____
7. Particulate pollutants are produced as result of incomplete combustion of hydrocarbons and are ______
8. _______ serve as pollution indicators.
9. ________ is an agent or factor that causes cancer.
10. ________ are the chemicals that are released in the air with a force in the form
of mist or vapour.
11. The process of polluting streams, rivers and lakes by excessive addition of organic fertilizers is known as ________
12. ______ pollution is caused by the discharge of hot water from cooling towers of power plants.
13. _______ is a physical phenomena in which energy travels through the space.
14. ______ is the lung disease caused due to inhalation of gritty dust.
15. Threshold is the _______ is a physical phenomena in which energy travels through the space. is the lung disease caused due to inhalation of gritty dust. intensity at which a sound becomes perceptible.
Answer:
1. pollutants
2. 0.05
3. particulate
4. toxicity
5. secondary
6. SO₂, SO₃
7. carcinogenic
8. Lichens
9. carcinogen
10. aerosols
11. eutrophication
12. thermal
13. radiation
14. silicosis
15. lowest

State whether the following statements are True or False. If False, then write the correct statement.

Question 1.
Atmospheric pollution is caused due to addition of harmful substances from uncontrollable non-human sources.
Answer:
True.

Question 2.
Pollutants resulting from human activities are mainly discharged in remote and isolated areas.
Answer:
False. Pollutants resulting from human activities are mainly discharged in cities and industrial centres.

Question 3.
Vapours of compounds whose boiling point is below 200° C are classified as gaseous pollutants.
Answer:
True.

Question 4.
Lung diseases are more common in rural areas because of more air pollution.
Answer:
False. Lung diseases are more common in urban areas because of more air pollution.

Question 5.
Vapours of compounds whose boiling point is below 200° C are known as particulate.
Answer:
False. They are known as gaseous.

Question 6.
Products of atmospheric reactions of hydrocarbons and nitrogen oxides in the presence of sunlight are called secondary pollutants.
Answer:
True.

Question 7.
Atmospheric diffusion of air is maximum at elevations of 3000m above the earth’s surface.
Answer:
False. It is minimum at this altitude.

Question 8.
Dust and mist consist of particles smaller than one micrometre.
Answer:
False. They consist of particles larger than one micrometer.

Question 9.
Lead is poisonous because it hampers haemoglobin formation.
Answer:
True.

Question 10.
Nitrogen oxide impairs the functioning of lungs by causing accumulation of water in the air spaces.
Answer:
True.

Question 11 .
Ethylene gas bleaches and damages plant-leaves.
Answer:
False. Ethylene causes premature failing of leaves.

Question 12.
Abundant growth of lichens indicates pollution free air.
Answer:
True.