Q. 1. What are the effects on our body of particulates of size 2.
5 micrometers? Ans. These particles are deep inhaled into lungs and cause— (i) breathing and respiratory problems. (ii) irritation, inflammation, damage to lungs. (iii) premature death. Q.
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2. (i) Why are auto vehicles filled with catalytic converters? (ii) What do these, devices have as catalyst? (iii) How are these converters useful? Ans. (i) Catalytic converters are devices fitted to auto vehicles to reduce atmospheric pollution, due to burning of petrol/diesel. (ii) Rhodium, platinum-palladium are the catalyst fitted to the converters.
(iii) These catalyst converters, convert the unburnt hydrocarbons into C02, H00, and CO and nitric oxide are converted into CO2,, N2. Q. 3. Mention any two advantages of CNG as a fuel for autovehicles. Ans.
(1) It cannot be adulterated. (2) It burns completely leaising very little unburnt and also efficiently. Q. 4.
What are the various constituents of domestic sewage? Discuss the effects of sewage discharge in a river? Ans. The domestic sewage contains— primarily biodegradable organic matter and many more substances effects of sewage discharge. The sewage discharged in the river results in consumption of oxygen by micro-organisms for biodegradation, mortality of fish and other aquatic organisms; algal bloom etc. The quality of water deteriorates and gives water a poor quality and makes it unfit for human consumption. Q.5. Define eutrophication.
What is cultural or accelerated eutrophication? Ans. The natural aging of lakes due to nutrient enrichment of water is called eutrophication. It may take thousands of years for natural eutrophication. Human activities, pollutants and other factors accelerate the natural aging process. This is called cultural/accelerated eutrophication. Q.
6. What is ‘sanitary land fill’? Give its one advantage and disadvantage. Ans. The process of burning the solid wastes in trench or low lying areas and covering it with dust is called sanitary land fill. The advantage is that wastes are not exposed and breeding of rats and flies cannot take place. Also foul smell emittance is not there.
The disadvantage is that the chemicals seepage takes place and’it will pollute the underground water resources. Q. 7. List all the wastes that you generate, at home, school or during your trips to other places, could you very easily reduce? Which could be difficult or rather impossible to reduce? Ans. List of some wastes generated are— Polyethenes, aluminium foil, paper, extra food, peels of vegetables, fruits, shells of nuts, egg shells, seeds, rotten food, cartons, bottles, blades, etc. Yes, some of the above can be easily reduced such as food, wrapping materials etc.
Sewage in rather difficult to reduce. (List of other items can be added to it.) Q. 8. Why ozone hole forms over Antarctica? How will enhanced ultraviolet radiation affect us? Ans. Though the depletion of ozone layer is widely in the stratosphere but particularly ozone layer is thin marked between late august and early October over Antarctica.
This is called ozone hole. The affects of ultraviolet radiation on human are— (a) skin damage and skin cancer. (b) Inflammation of cornea (snow blindness), cataract. (c) Mutation. Q. 9. Expand the terms— Ans. DU, CFC, FOAM, PIL, CNG, CPCB.
(1) Dobson Unit (2) Chlorofluorocarbon (3) Friends of the Areata Marsh (4) Public Interest Litigation (5) Compressed Natural gas (6) Central Pollution Control Board Q. 10. Discuss the role of women and communities in protection and conservation of forests? Ans. Women and communities have played a major role in protection and conservation of forests. Two examples are: Protection of forest trees by Bishnoi Community: In olden days Bishnoi community played a major role in protecting their forest trees in Rajasthan. The women Leader Amrita Devi sacrificed her life for the cause followed by her daughters and her community. Such an example is not witnessed in any part of world except India.
Chipko Movement: Similar movement to protect the trees of hills by Garhwal Himalayas in 1974 was shown. The women of this region hugged the trees and protected them from the axe of timber contractors. People all over the world acclaimed the move.
Q. 11. What measures, as an individual, you would take to reduce environmental pollution? Ans. Following measures I would undertake to reduce environmental pollution are— (1) Reduce the use of poly bags, packed materials, autovehicles – car, scooter.
(2) Use recycled materials. (3) Dump or use dust bin, poly bags for solid wastes dumping. (4) Minimize the use of substances that cause pollution during production.
Q. 12. Discuss briefly the following: (a) Radioactive wastes (b) Defunct ships and e-wastes (c) Municipal solid wastes.
Ans. (a) Radioactive Wastes: Radioactive materials are the source of nuclear energy which is used to generate electricity. This source of electrical energy poses a serious problem in the disposal of radioactive wastes and radiation leakage.
Already two accidental leakages have taken place in past. It causes damages to organisms because of high mutation rates. It also creates disorders, such as cancer on lower doses. It is extremely potent pollution and it has to be dealt with caution.
Hence, the wastes are suitably shielded in containers and buried about 500 in deep below the earth. (a) Defunct Ships and e-wastes: e-wastes are electronic goods that are irreparable. These wastes are generated in the developed countries and exported to developing countries such as India for dumping. These are either buried in landfills or incinerated.
They are also recycled and metals like copper, iron, silicon, nickel and gold are recovered. The recycling of e-wastes in our country involves manual participation. Thus exposing the workers to toxic substances present in e-wastes. (b) Municipal Solid Wastes: These are the wastes produced from homes, offices, stores, schools, hospitals etc. These are—plastics, glass, metals, food wastes, plastic, paper, etc.
Burning these causes reduction in volume of wastes but produces air pollution, dumping in open serves as breeding ground for rats and flies. Therefore, an alternative method for disposal is sanitary landfills. This also is not cent per cent foolproof as it causes seepage of chemicals to underground water resources. Q. 13. What initiatives were taken for reducing vehicular air pollution in Delhi? Has air quality improved in Delhi? Ans. To reduce the vehicular pollution in Delhi following measures were taken: (/) Buses are being run on CNG.
(ii) Other private vehicles are also using CNG—the clean fuel. (iii) Use of unleaded, low-sulphur petrol and diesel. (iv) Use of catalytic converters in auto vehicles, (v) All vehicles to meet Bharat stage III norms.
(vi) Old vehicles to be replaced by new ones following the prescribed norms. Q. 14. Discuss briefly the following: (a) Greenhouse gases (b) Catalytic converter (c) Ultraviolet B Ans. (a) Greenhouse gases: The increase in the global temperature during the past century by 0.6? is by green house gases. This has been mostly in past three decades. Various greenhouse gases are—CO2 CH4, N20, CFC.
Of these the major contributors are CO2 (60%) and methane (20%) to total global warming. This rise in temperature due to global warming is leading to deleterious changes in the environment and resulting in odd climatic changes, (e.g. El Nino effect). (a) Catalytic converter: There are devices fitted to auto vehicles that run on petrol.
These work on unleaded petrol (leaded petrol) inactivates the catalyst). The converter has platinum, palladium and rhodium as catalysts. These convert the unburnt hydro carbon into CO2, and H20 gas, and carbon monoxide and nitric oxide into C02 and N-, gas. This reduces the atmospheric pollution as the exhaust does not have poisonous gases, unburnt hydrocarbons. (c)Ultraviolet B: UV-B radiation is present in the UV radiation. These rays are damaging and cause damages to DNA and mutation. The aging of skin, cancer of skin, damages skin and effects eye. The human eye absorbs it and causes inflammation of cornea called snow blindness, cataract etc.
on high dose of UV-B. It can also result in permanent damage to cornea.