Class 11 Environment Chapter 5 Environmental Pollution

Class 11 Environment Chapter 5 Environmental Pollution The answer to each chapter is provided in the list so that you can easily browse through different chapters Assam Board HS 1st Year Environmental Studies Chapter 5 Environmental Pollution Question Answer.

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Class 11 Environment Chapter 5 Environmental Pollution

Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 11 Environment Chapter 5 Environmental Pollution Notes for All Subjects, You can practice these here.

Environmental Pollution

UNIT – 5


Textual Questions and Answers

1. What do you mean by environmental pollution? Name the different types of pollution.

Ans: The term pollution have derived from latin word pollute. Pollute means make dirty. Thus pollution means a change in the physical, chemical and biological aspects of environment. This pollution is very harmful to human life and all other living beings.

Different types of pollution :

(i) According to environment: When different segments of the environment are affected by pollution, they may be categorized as

(a) Air pollution

(b) Water pollution

(c) Soil pollution

(ii) According to pollutant: pollution caused by pollutants may be of different types such as

(a) Thermal pollution 

(b) Noise pollution

(c) Radioactive pollution

(d) Solid waste pollution

(e) Oil pollution

(f) Industrial pollution

(g) Marine pollution

2. What is air pollution? Identify the sources of air pollution. 

Ans: The presence of pollutants in air which is the cause of injury and damage to human beings, animals, plants and other objects is called air pollution.

The sources of air pollution are:

(i) Natural sources :

(a) Volcanic eruption: Releasing poisonous gases like SO₂, H₂S₂CO etc.

(b) Forest fires : In the areas of tropical region throughout the year forest fire is a common feature. very large quantities of smoke and particulate matter are released during their breakout.

(c) Natural organic and inorganic decays or vegetative decays. methane gas, carbon dioxide are released into the air

(d) Dust: Dust is always present in the atmosphere in varying amounts.

(e) Pollen grains of flowers: PollutioN is also caused by the production of pollens in the spring season.

Pollens or aeroallergens enter the atmosphere form weeds, grasses and trees. They are mainly responsible for causing allergy.

(f) Fungal spores: Micro-organisms such as algae, fungi, bacteria, yeasta, rusts spores etc are present as variable particles in the atmosphere.

(g) Radioactive materials: The radioactive minerals present in the earth crust and action of cosmic rays from outer space on gaseous constituents of the atmosphere are mainly responsible for radioactivity of the atmosphere.

(ii) Man made sources :

(a) Deforestation

(b) Burning of fossil fuels

(c) Emission from vehicles

(d) Rapid industrialization

(e) Modern agricultural practices

3. Mention few effects of air pollution on human health. 

Ans: Few effects of air pollution on human health-

Air pollutantSources of productionEffects on man
1.Sulphur-dioxideCoal & oil combustion constriction.Causes chest pain headache, vomiting, death from respiratory ailments
2.Nitrogen OxidesSoft coal & automobile exhausts, unvented gas stove, kerosene heaters, wood stoves Inhibits cilia action so that soot and dust penet rate far into the lungsHeadache,drowsiness, irritated lungs, children’s colds
3.Carbon monoxideBurning of coal, gasoline, motor exhausts, faulty furnaces, unvented gas stove, kerosene heaters, wood burningCauses nausea, reduces oxygen carrying capacity of blood, headache, drowsiness irregular heartbeat
4.SPM ash, soot smoke etc.Incinerators & every manufacturing processesCauses eye irritation, emphysema, cancer
5.Hydrogen sulphideRefineries, chemical industries, bituminous fuelsCauses nausea, irritation of eyes and throat
6.AmmoniaExplosives, dye making fertilizer plants passagesInflames upper respiratory
7.Phosgene or carbonyl chlorideChemical and dye makingInduce coughing irritation and fatal pulmonary edema
8.AldehydesThermal decomposition of oils, fats or glycerolIrritate nasal and respiratory tracts
9.Suspended particleIncinerators and almost every manufacturing processcause emphysema, eye irritation, cancer
10.AsbestosPipe insulation, vinyl ceiling floor tilesLung diseases, lung cancer

Q.4 what is water pollution ? What are the effects of water pollution on human health?

Ans: When water contains substances more than it is wanted or t contains harmful elements, germs or particles, then the water is called polluted water. The physical and chemical properties of such water is substantially different from pure water. The degree of difference indicates the degree of pollution.

The effects of water pollution on human health are:

(i) Typhoid : Salmonella typhi

(ii) Cholera: vibrio cholerae

(iii) Dysentery: shigella

(iv) Diarrhea: cryptosporidium 

(v) Giardiasis: giardia lamblia 

(vi) Diarrhea: e coli

(vii) Gastroenteritis: viruses

(viii) Polia: polioviruses 

Contamination of drinking water, either directly or indirectly by sewage and other wastes or by human or animal excrement is to most common and widespread danger associated with water quality problem particularly in the underdeveloped world. Faecal pollution leads to introduction of a variety of intestinal pathogens bacteria, virus and parasites causing diseases starting from mild gastroenteritis to severe and fatal dysentery, cholera or typhoid When drinking water is contaminated with sewage, gastroenteritis and infectious hepatitis may occur in epidemic proportion. Other diseases like rashes, fever, myocarditis, meningitis, respiratory diseases etc. are also likely. Protozoic diseases like amoebiasis, giardiasis may also occur through sewage contamination of water sources.

5. What is soil pollution? How it can be controlled? 

Ans: Decrease in soil fertility because of addition of some foreign elements is called soil pollution. Soil is polluted with dumping of solid wastes generated in the household and manufacturing units.

Control of soil pollution :

(a) Industrial effluents should be properly treated before discharging them into the soil.

(b) Solid wastes should be properly segregated as biodegradable and non biodegradable wastes at source and than disposed off by adopting effective scientific methods.

(c) Use of bio-fertilizers instead of chemical fertilizers should be encouraged.

(d) Application of pesticides should be controlled.

(e) Bioremediation can be adopted for degradation of toxic chemicals present in soil.

(f) Necessary enactment of laws should be made for panel action against those who are involved in polluting soil.

(g) Awareness should be created among people.

6. What are solid wastes? How are they classified.Give examples.

Ans: Higher standard of living of ever increasing population has resulted in an increase in the quantity and variety of waste generated. Solid wastes, i.e. the wastes other than liquid or gaseous wastes can be classified as municipal, industrial, agricultural, medical, mining waste and sewage sludge.

Urban waste consists of

(i) Domestic waste containing a variety of discarded materials, like, polythene bags, empty metal and aluminium cans, scrap metals, glass bottles, waste paper, food waste etc.

(ii) Waste from shops mainly consists of waste paper, packaging material, cans, bottles, egg shells, tea leaves etc.

(iii) Biomedical waste includes anatomical wastes, pathological wastes, infectious wastes etc.

(iv) Construction/demolition waste includes debris and rubbles, wood, concrete etc.

(v) Horticultural waste and waste from slaughter houses include vegetable parts, residues and remains of slaughtered animals etc.

Industrial waste consists of a large number of materials including fac tory rubbish, packaging material, acids, alkalis and metals etc. During some industrial processing, large quantities of hazardous and toxic mate rials are also produced. The main sources of industrial wastes are chemical cal industries, metal and mineral processing industries. Radioactive wast are generated by nuclear power plants. Solid wastes from other types of industries include plastic, paper, glass, wood, oils, paints, heavy, metala asbestos, batteries etc.

7. Discuss the environmental effects of solid wastes. 

Ans: The environmental effects of solid wastes are: 

(i) Open dumps are malodorous places in which disease carrying vermins such as rats and flies proliferate.

(ii) Methane gas is released into the surrounding are due to decomposition of solid waste by microorganisms.

(iii) Liquid that oozes and seeps through solid waste heap ultimately finds its way into the soil, surface water and ground water.

(iv) Hazardous materials dissolved in the liquid contaminate underground water and soil strata.

(v) Solid waste is highly heterogeneous and is not segregated at any stage. It includes wastes from industries, hospitals and nursing homes, domestic waste etc.

(vi) The leachate consisting of a variety of chemical constituents, seeps and pollute the ground water.

(vii) Absence of landfill liners aggravate the problem.

(viii) Health hazards faced by the residents living in the nearby areas of dumping sites can not be ignored.

(ix) The present practice of collecting solid waste from individual houses results in wastage of time and thereby increases the cost of collection.

(x) Transportation of collected solid wastes openly by the tractors or trucks is unhygienic and the aesthetic look of the city is also affected. 

8. What are the major greenhouse gases? What is effect?

Ans: The major Green House Gases are Carbon Dioxide, Methane, Nitrous Oxide, Chlorofluorocarbons (CFCs), Water vapour and Ozone.

Green House Effect: The carth is the only planet in our solar system that supports life. The evolution of life on earth was possible because of the presence of a unique set of environmental conditions viz. water, oxygen rich atmosphere, land and a suitable surface temperature. The earth has an atmosphere of proper thickness and chemical composition. About 30% of the incoming energy from the sun is reflected back to spece while the rest (70%) reaches the earth, warming the air, water, land and maintaining an average surface temperature at about 150C. During the day, energy from the sum (largely in the visible part of the spectrum) is absorbed by the earth’s surface. If all this energy were to be absorbed t completely, the earth would gradually become hotter. But in reality, the earth both absorbs and simultaneously releases energy in the from of infrared radiations (long wavelength, less energetic). All the rising heat is not lost to space, but is partly absorbed by some gases present in the atmosphere in very small quantities, called the Green House Gases (GHGs),

9. What do mean by global warming? Mention few consequences of global warming.

Ans: Due to the greenhouse effect, the average surface temperature of the earth is at about 15°C and the earth becomes hospitable to a variety of life forms. If the GHGs do not perform this function, most of the energy would escape, leaving the earth cold (about-18°C) and the earth would become unfit to support life. Heat trapped by the greenhouse gases in the atmosphere keeps the planet warm enough to allow us and other species to exist. But due to different natural as well as anthropogenic activities the concentration of the greenhouse gases in the atmosphere has increased during the past several decades. Scientists estimate that the earth’s average temperature has increases by 0.3-0.6°C since the beginning of the last century. Ever since the industrial revolution, began 150 years ago, manmade activities have added significant quantities of greenhouse gases to the atmosphere. The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased by about 31%, 171% and 17% respectively between 1750 and 2000 (IPCC,2001) The rise in temperature due to the blanketing effect of increased level of greenhouse gases is termed as global warming. 

Few consequences of Global Warming are :

(i) Climate change

(ii) Depletion of ozone layer (Greenhouse effect)

(iii) Acid Rain

10. What is acid rain?

Ans: Oxides of sulphur and nitrogen originating from industrial operations and fossil fuel burning are the major sources of acid forming gases in the atmosphere. When sulphur dioxide and nitrogen oxides are transported by prevailing winds, they come in contact with water vapour and form sulphuric acid and nitric acid respectively, droplets of sulphuric acid and small particulates of sulphates and nitrates. These chemical substances come down to the earth’s surface in two forms-wet (as acid rain, snow, fog and cloud vapour etc) and dry (as acidic particles). The resulting mixture is called acidic deposition or commonly called acid rain.

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