Jkbose class 12th Evs short notes

JKBOSE Class 12th • Environmental Science

Complete Short Revision Notes

10 Units • 7 Marks Each

Simple English • Exam Revision • Complete Syllabus

Prepared for quick learning, answer writing and last-day revision

How to study: First learn the definition. Then remember causes, effects, control measures and examples. For a 7-mark answer, write a short introduction, 5–7 points and a conclusion.

Index / Contents

1. Unit 1: Air Pollution and Control
2. Unit 2: Noise and Radiation Pollution
3. Unit 3: Water Pollution
4. Unit 4: Soil and its Degradation
5. Unit 5: Solid and Hazardous Waste Management
6. Unit 6: Biodiversity Management
7. Unit 7: Global Environmental Issues
8. Unit 8: Regional and Local Environmental Issues
9. Unit 9: Sustainable Development
10. Unit 10: Environmental Legislation and International Conventions
11. Rapid Revision Sheet
12. Important Board Questions

UNIT 1: Air Pollution and Control • 7 Marks

Air Pollution: Sources and Types

• Air pollution is the presence of harmful solid, liquid or gaseous substances in air in amounts that damage living organisms, property or the environment.
• Natural sources: volcanic eruptions, forest fires, dust storms, pollen and decomposition.
• Human-made sources: vehicles, industries, thermal power plants, construction, mining, burning of waste and crop residue.
• Primary pollutants: directly released into air, such as CO, SO₂, NO, dust and smoke.
• Secondary pollutants: formed in the atmosphere by chemical reactions, such as ozone and photochemical smog.

Impact of Air Pollution on Environment

• Causes breathing problems, asthma, bronchitis and other health problems.
• Reduces plant growth and damages leaves through toxic gases.
• Produces acid rain, which harms soil, water bodies, forests and buildings.
• Contributes to global warming and climate change through greenhouse gases.
• Reduces visibility and creates smog.
• Damages monuments and buildings through chemical reactions.

Criteria Pollutants

• Particulate matter: PM₁₀ and PM₂.₅; enters the respiratory system.
• Carbon monoxide (CO): reduces oxygen transport in blood.
• Sulphur dioxide (SO₂): mainly released by burning sulphur-containing fuels.
• Nitrogen oxides (NOₓ): produced mainly by vehicles and combustion.
• Ozone (O₃): harmful near the ground but protective in the stratosphere.
• Lead: affects the nervous system and other body functions.

Indoor Air Pollution

• Indoor pollution occurs inside homes, schools, offices and other buildings.
• Sources include biomass fuel, coal, tobacco smoke, incense, paints, cleaning chemicals, mould and poor ventilation.
• Effects include headache, eye irritation, cough, asthma and respiratory disease.
• Control: clean fuel, chimneys, ventilation, smoke-free rooms, regular cleaning and low-emission products.

Control of Air Pollution

• Particulate matter: settling chambers, cyclones, scrubbers, electrostatic precipitators and bag filters.
• Gaseous pollutants: absorption, adsorption, condensation and catalytic conversion.
• Use cleaner fuels, renewable energy and public transport.
• Maintain vehicles and use emission-control devices.
• Plant trees and prevent open burning of waste.
• Use industrial monitoring, proper chimney height and pollution-control equipment.

Exam memory: Air pollution control = prevent pollution at source + collect particles + remove harmful gases + use clean energy.

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UNIT 2: Noise and Radiation Pollution • 7 Marks

Noise Pollution: Sources and Effects on Health

• Noise pollution is unwanted or excessive sound that disturbs normal life and harms health.
• Sources: road traffic, trains, aircraft, industries, construction, loudspeakers, generators and household appliances.
• Effects include hearing loss, stress, headache, sleep disturbance, high blood pressure, poor concentration and anxiety.
• Children may face learning and attention problems due to continuous loud noise.

Prevention and Control of Noise Pollution

• Use silencers and maintain vehicles and machines.
• Create silence zones near hospitals, schools and courts.
• Use sound barriers and green belts near roads and industries.
• Control loudspeakers, horns and construction timing.
• Use ear protection in noisy workplaces.
• Follow prescribed noise standards and conduct awareness programmes.

Radiation Pollution: Concept and Causes

• Radiation pollution is harmful exposure to ionising radiation above safe limits.
• Sources: nuclear power plants, nuclear accidents, radioactive waste, medical X-rays, research laboratories, mining of radioactive minerals and nuclear weapons testing.
• Ionising radiation: alpha particles, beta particles, gamma rays and X-rays.

Effects of Radioactive Pollution

• Damages cells and DNA.
• Causes burns, radiation sickness and cancer.
• May produce genetic mutations and birth defects.
• Damages reproductive organs and immune systems.
• Radioactive substances may remain in soil and water for a long time.
• Radiation can move through food chains and affect many organisms.

Control Measures

• Safe storage, transport and disposal of radioactive materials.
• Use shielding, distance and minimum exposure time.
• Regular monitoring and personal dosimeters for workers.
• Emergency planning around nuclear facilities.
• Proper maintenance of nuclear plants and strict safety rules.
• Use radioactive waste treatment and secure long-term storage.

Radiation safety principle: Reduce exposure time + increase distance + use proper shielding.

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UNIT 3: Water Pollution • 7 Marks

Surface and Groundwater Pollution

• Water pollution is the addition of harmful substances to water that reduces its quality and makes it unsafe for use.
• Sources: domestic sewage, industrial effluents, agricultural fertilisers and pesticides, oil spills, mining and solid waste.
• Surface water: rivers, lakes, ponds and streams are polluted by direct discharge and runoff.
• Groundwater: polluted when chemicals, sewage, landfill leachate and pesticides enter the soil and reach underground water.
• Effects: diseases, oxygen depletion, fish death, bad smell, unsafe drinking water and loss of aquatic biodiversity.

Eutrophication

Eutrophication is the excessive growth of algae and aquatic plants due to high nutrients, mainly nitrates and phosphates.

• Sources: fertilisers, sewage and detergents.
• Algal bloom blocks sunlight and reduces oxygen when algae decompose.
• Low dissolved oxygen may cause fish death and formation of dead zones.

Biomagnification

Biomagnification is the increase in concentration of a persistent toxic substance at higher levels of a food chain.

• Example: pesticide or mercury enters water → plankton → fish → birds or humans.
• Top consumers receive the highest concentration.
• Persistent, fat-soluble and non-degradable chemicals show biomagnification.

Marine Pollution

• Marine pollution is the entry of harmful substances into seas and oceans.
• Sources include plastic, sewage, oil spills, industrial waste, agricultural runoff and ship activities.
• Effects include death of marine organisms, plastic ingestion, oil-coated birds, coral damage and oxygen depletion.
• Control includes reducing plastic, treating sewage, preventing oil spills and protecting coastal ecosystems.

Water Pollution Control

• Treat domestic sewage and industrial wastewater before discharge.
• Reduce fertiliser and pesticide use.
• Protect wetlands, riverbanks and groundwater recharge areas.
• Use rainwater harvesting and water conservation.
• Monitor water quality and enforce pollution standards.
• Prevent dumping of plastic, chemicals and untreated waste.

Sewage Treatment Plant

Primary

→

Secondary

→

Tertiary

• Primary treatment: physical removal through screening, grit removal and sedimentation.
• Secondary treatment: biological decomposition of organic matter by microorganisms; reduces BOD.
• Tertiary treatment: advanced treatment to remove nutrients, pathogens, salts and remaining pollutants.
• BOD: Biochemical Oxygen Demand; oxygen needed by microorganisms to decompose organic matter.

Remember: Eutrophication = nutrients and algal bloom. Biomagnification = increasing toxic concentration along food chains.

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UNIT 4: Soil and its Degradation • 7 Marks

Soil: Composition and Profile

• Soil is the upper loose layer of land that supports plant growth.
• Composition: mineral particles, organic matter or humus, water, air and living organisms.
• Soil profile: O horizon (organic matter), A horizon (topsoil), B horizon (subsoil), C horizon (parent material) and R horizon (bedrock).
• Topsoil is rich in humus and supports most biological activity.

Indian Classification of Soils

Soil type	Main features
Alluvial	Deposited by rivers; fertile; common in plains.
Black	Clay-rich; holds moisture; suitable for cotton.
Red and Yellow	Rich in iron; found in many peninsular regions.
Laterite	Develops under heavy rainfall and leaching.
Desert/Arid	Sandy, low organic matter and common in dry regions.
Mountain/Forest	Found in hilly areas; properties change with altitude.

Soil Pollution: Causes, Impacts and Control

• Causes: pesticides, fertilisers, industrial chemicals, mining, plastics, sewage sludge and dumping of waste.
• Impacts: reduced fertility, toxic crops, groundwater pollution, death of soil organisms and entry of toxins into food chains.
• Control: organic farming, safe waste disposal, bioremediation, crop rotation, limited chemical use and soil testing.

Soil Erosion

• Soil erosion is the removal of fertile topsoil by water, wind or human activities.
• Causes: deforestation, overgrazing, construction, mining, intense rainfall and improper farming.
• Impacts: loss of fertility, sedimentation of rivers, floods, landslides and reduced crop production.
• Control: contour ploughing, terrace farming, strip cropping, shelter belts, afforestation, mulching and check dams.

Desertification and Control

• Desertification is land degradation in dry areas due to climatic variations and human activities.
• Causes: deforestation, overgrazing, over-irrigation, soil erosion, drought and poor land management.
• Control: water harvesting, drought-resistant crops, afforestation, controlled grazing, soil conservation and sustainable farming.

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UNIT 5: Solid and Hazardous Waste Management • 7 Marks

Solid Waste: Sources, Generation and Impacts

• Solid waste includes unwanted solid or semi-solid materials generated by homes, markets, industries, hospitals, agriculture and construction.
• Sources: municipal waste, industrial waste, biomedical waste, agricultural waste, construction waste and e-waste.
• Impacts: bad smell, insects, disease, soil and water pollution, methane production, fires and visual pollution.

Management of Solid Waste

• Follow the waste hierarchy: Refuse → Reduce → Reuse → Repair → Recycle → Recover → Dispose.
• Segregate waste at source into wet, dry and hazardous categories.
• Compost biodegradable waste.
• Recycle paper, glass, metals and suitable plastics.
• Use material recovery facilities and safe transportation.
• Create public awareness and enforce waste-management rules.

Disposal Methods

Method	Short explanation
Composting	Biological decomposition of organic waste into compost.
Incineration	Controlled burning at high temperature; reduces waste volume.
Pyrolysis	Thermal breakdown of waste with little or no oxygen.
Sanitary landfill	Engineered disposal with liners, leachate collection and gas control.

E-waste and its Management

• E-waste means discarded electrical and electronic equipment.
• Contains useful materials as well as hazardous substances such as lead, mercury and some flame retardants.
• Impacts: toxic soil and water pollution, health problems and loss of valuable metals.
• Management: repair, reuse, authorised collection, producer responsibility, safe dismantling and recycling.

Hazardous Waste

Hazardous waste is waste that can cause danger to human health or the environment because of its toxic, corrosive, reactive, ignitable or infectious nature.

• Types: chemical waste, industrial waste, biomedical waste, pesticide waste, radioactive waste and certain electronic waste.
• Characteristics: ignitability, corrosivity, reactivity, toxicity and sometimes infectiousness.

Management of Hazardous Waste

• Deep well injection: placing suitable liquid hazardous waste deep underground in carefully selected geological formations.
• Plasma torch: very high temperature treatment that breaks down waste into simpler substances; requires strict pollution control.
• Incineration: controlled high-temperature burning; gases and ash must be safely treated.
• Other steps: identification, segregation, labelling, safe transport, treatment, secure landfill and monitoring.

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UNIT 6: Biodiversity Management • 7 Marks

Levels and Importance of Biodiversity

• Biodiversity means the variety of life at genetic, species and ecosystem levels.
• Genetic diversity: variation within a species, such as different varieties of crops.
• Species diversity: variety and number of species in an area.
• Ecosystem diversity: variety of ecosystems such as forests, wetlands, grasslands and deserts.
• Importance: food, medicine, pollination, soil formation, climate regulation, cultural value and ecological stability.

Threats to Biodiversity

• Habitat loss and fragmentation.
• Deforestation and land-use change.
• Overexploitation, hunting and illegal wildlife trade.
• Pollution of air, water and soil.
• Invasive alien species.
• Climate change, forest fires and natural disasters.

Threatened Species as per IUCN

• IUCN means International Union for Conservation of Nature.
• Threat categories include Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild and Extinct.
• Threatened categories: Vulnerable, Endangered and Critically Endangered.
• Assessment is based on population decline, population size, geographic range and risk of extinction.

Biodiversity Hotspots

• A biodiversity hotspot is a region with high endemism and serious habitat loss.
• Generally, a hotspot must contain many endemic vascular plant species and must have lost a large part of its original natural vegetation.
• India-related hotspots include Himalaya, Indo-Burma, Western Ghats–Sri Lanka and Sundaland (Nicobar Islands).

Biodiversity Conservation

In-situ conservation	Ex-situ conservation
Protection in natural habitat.	Protection outside natural habitat.
National parks, wildlife sanctuaries, biosphere reserves.	Zoos, botanical gardens, seed banks, gene banks and captive breeding.
Protects species with their ecosystem.	Useful for endangered species and genetic material.

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UNIT 7: Global Environmental Issues • 7 Marks

Introduction

Global environmental issues affect many countries and require international cooperation. Major issues include climate change, global warming, ozone depletion, acid rain and smog.

Climate Change and Global Warming

• Global warming is the long-term increase in Earth’s average temperature mainly due to enhanced greenhouse effect.
• Climate change includes long-term changes in temperature, rainfall, winds, sea level and extreme events.
• Causes: burning fossil fuels, deforestation, industries, transport, agriculture and waste.
• Consequences: melting glaciers, sea-level rise, heat waves, changing rainfall, crop stress, biodiversity loss and health risks.
• Control: renewable energy, energy efficiency, afforestation, public transport, sustainable agriculture and reduction of greenhouse gases.

Ozone Layer Depletion

• The stratospheric ozone layer absorbs harmful ultraviolet radiation.
• Causes: CFCs, halons and other ozone-depleting substances release chlorine and bromine in the stratosphere.
• Consequences: skin cancer, cataracts, immune-system damage and harm to plants and aquatic organisms.
• Control: phase out ozone-depleting substances, use safer alternatives, maintain equipment and follow the Montreal Protocol.

Acid Rain

• Acid rain is precipitation made acidic mainly by sulphur dioxide and nitrogen oxides.
• These gases form sulphuric and nitric acids in the atmosphere.
• Impacts: damage to forests, acidification of lakes, soil nutrient loss, fish death and corrosion of buildings.
• Control: low-sulphur fuels, scrubbers, catalytic converters, renewable energy and emission standards.

Smog: Concept, Types, Impacts and Control

• Smog is a polluted mixture of smoke, gases and fog or atmospheric pollutants.
• Classical smog: associated with smoke, sulphur dioxide and cool humid conditions.
• Photochemical smog: forms when nitrogen oxides and volatile organic compounds react in sunlight; ozone is a major component.
• Impacts: eye irritation, breathing problems, reduced visibility and plant damage.
• Control: reduce vehicle emissions, use clean fuels, public transport, industrial controls and avoid open burning.

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UNIT 8: Regional and Local Environmental Issues • 7 Marks

Introduction

Regional and local environmental issues are problems affecting a particular area due to local geography, industries, population, tourism, agriculture and land-use patterns.

Impact of Industries: Brick Kilns and Cement Industries

• Brick kilns: release smoke, particulate matter, sulphur compounds and black carbon; use of topsoil can reduce soil fertility.
• Brick kiln impacts include air pollution, occupational health risks, land degradation and fuel consumption.
• Cement industries: generate dust, nitrogen oxides, sulphur dioxide, carbon dioxide, noise and mining-related impacts.
• Control: cleaner fuels, improved kiln technology, dust filters, electrostatic precipitators, green belts, worker protection and regular monitoring.

Degradation of Lakes, Wetlands and Springs

• Causes: sewage discharge, solid waste, encroachment, siltation, excessive water extraction, tourism pressure and climate variation.
• Effects: reduced water quality, biodiversity loss, eutrophication, drying of springs and flood-control failure.
• Control: sewage treatment, catchment protection, wetland restoration, removal of encroachments, rainwater harvesting and community participation.

Tourism: Impacts and Alternatives

• Positive impacts: employment, income, cultural exchange and support for conservation.
• Negative impacts: waste, traffic, water demand, noise, construction, habitat disturbance and pressure on local resources.
• Sustainable alternatives: ecotourism, carrying-capacity limits, waste segregation, local guides, public transport, eco-friendly accommodation and responsible visitor behaviour.

Deforestation: Causes, Consequences and Control

• Causes: agriculture, roads, mining, industries, urbanisation, dams, fuelwood collection and illegal cutting.
• Consequences: biodiversity loss, soil erosion, floods, climate change, reduced rainfall, habitat fragmentation and livelihood problems.
• Control: afforestation, social forestry, agroforestry, protected areas, sustainable forest management, community participation and strict law enforcement.

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UNIT 9: Sustainable Development • 7 Marks

Concept, History and Characteristics

Sustainable development means development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

• The idea became widely known through the Brundtland Report of 1987.
• The 1992 Earth Summit increased global focus on sustainable development.
• Characteristics: long-term thinking, resource conservation, equity, participation, pollution reduction and balance between development and environment.

Sustainable Development Goals

• The United Nations adopted 17 Sustainable Development Goals (SDGs) in 2015 under the 2030 Agenda.
• Examples: no poverty, zero hunger, good health, quality education, clean water, affordable clean energy, climate action, life below water and life on land.
• SDGs are interconnected and aim to improve human well-being while protecting the planet.

Components of Sustainable Development

Component	Meaning
Society	Equality, health, education, safety and participation.
Environment	Conservation of biodiversity, resources and ecological balance.
Culture	Protection of traditions, heritage and local knowledge.
Economy	Employment, income and development without resource destruction.

Ecotourism

• Ecotourism is responsible travel to natural areas that conserves the environment and supports local communities.
• Principles: low environmental impact, conservation education, local employment, respect for culture and limited resource use.
• Examples include guided nature walks, bird watching and community-based tourism.

Environmental Impact Assessment (EIA)

• EIA is a process used to identify and evaluate possible environmental impacts of a proposed project before approval.
• Scope: industries, roads, dams, mining, power plants, townships and other major projects.
• Key elements: screening, scoping, baseline data, impact prediction, alternatives, public consultation, environmental management plan, decision-making and monitoring.
• Importance: reduces environmental damage, improves planning and supports informed decisions.

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UNIT 10: Environmental Legislation and International Conventions • 7 Marks

Water (Prevention and Control of Pollution) Act, 1974

• Objective: prevent and control water pollution and maintain or restore the wholesomeness of water.
• Provides for CPCB and SPCBs.
• Controls discharge of sewage and industrial effluents.
• Allows inspection, sampling, monitoring and legal action.
• Industries may require consent for discharge-related activities.

Air (Prevention and Control of Pollution) Act, 1981

• Objective: prevent, control and reduce air pollution.
• Provides roles for CPCB and SPCBs.
• Allows declaration of air pollution control areas.
• Controls industrial emissions and provides for consent in applicable areas.
• Includes inspection, sampling, standards, directions and penalties.

Environment (Protection) Act, 1986

• Broad umbrella law for protection and improvement of the environment.
• Provides powers to the Central Government to prescribe standards and regulate industries.
• Supports control of hazardous substances and environmental emergencies.
• Allows directions, inspections, laboratories, rules and notifications.

Disaster Management Act, 2005

• Provides a legal framework for prevention, mitigation, preparedness, response, relief, rehabilitation and recovery.
• Creates NDMA at national level, SDMA at state level and DDMA at district level.
• Supports disaster-management plans, training, mock drills, coordination and emergency response.

International Conventions

Convention/Protocol	Year	Main focus
Kyoto Protocol	1997	Greenhouse-gas emission commitments and climate change.
Montreal Protocol	1987	Protection of ozone layer by controlling ozone-depleting substances.
Ramsar Convention	1971	Conservation and wise use of wetlands.
CITES	1973	Regulation of international trade in wild fauna and flora.

Quick Features

• Kyoto Protocol: focuses on greenhouse gases and climate change.
• Montreal Protocol: controls CFCs, halons and other ozone-depleting substances.
• Ramsar Convention: protects wetlands and promotes wise use.
• CITES: regulates international trade in listed wild species through Appendices and permits.
• Memory pair: Kyoto–Climate; Montreal–Ozone; Ramsar–Wetlands; CITES–Wildlife trade.

Exam tip: Always write the year, objective, 4–6 features and importance of each Act or convention.

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Rapid Revision Sheet

• PM₂.₅ is smaller than PM₁₀ and can penetrate deeper into the lungs.
• CO reduces oxygen-carrying capacity of blood.
• Noise is measured in decibels (dB).
• Radiation safety: time, distance and shielding.
• Eutrophication is caused by excess nutrients.
• Biomagnification increases at higher trophic levels.
• Primary sewage treatment is physical; secondary is biological; tertiary is advanced treatment.
• Topsoil is mainly associated with the A horizon.
• Composting converts organic waste into useful manure-like material.
• Hazardous waste may be toxic, corrosive, reactive or ignitable.
• Genetic, species and ecosystem are the three levels of biodiversity.
• In-situ means conservation in natural habitat; ex-situ means outside natural habitat.
• Vulnerable, Endangered and Critically Endangered are threatened IUCN categories.
• Global warming is mainly linked with enhanced greenhouse effect.
• Ozone depletion is linked with CFCs and halons.
• Acid rain is mainly related to SO₂ and NOₓ.
• Photochemical smog forms in sunlight from NOₓ and VOCs.
• Ecotourism should conserve nature and support local communities.
• EIA is conducted before approval of many major projects.
• Water Act: 1974; Air Act: 1981; EPA: 1986; Disaster Management Act: 2005.

Important Board Questions

Very Short Answer Questions

1. Define air pollution.
2. What are criteria pollutants?
3. Define noise pollution.
4. What is radiation pollution?
5. Define eutrophication.
6. What is biomagnification?
7. Name the three stages of sewage treatment.
8. What is soil erosion?
9. Define e-waste.
10. What is biodiversity?
11. What is a biodiversity hotspot?
12. Define global warming.
13. What is acid rain?
14. What is ecotourism?
15. Define sustainable development.
16. What is EIA?
17. Write the year of the Water Act.
18. Which protocol protects the ozone layer?

Short and Long Answer Practice

1. Explain the sources, effects and control of air pollution.
2. Describe indoor air pollution and its control measures.
3. Explain the health effects and control of noise pollution.
4. Discuss the causes, effects and control of radioactive pollution.
5. Explain eutrophication and biomagnification with examples.
6. Describe primary, secondary and tertiary sewage treatment.
7. Explain soil profile and Indian soil types.
8. Discuss soil pollution, soil erosion and desertification.
9. Explain solid waste management and disposal methods.
10. Write a note on e-waste and hazardous waste.
11. Explain levels, importance and threats to biodiversity.
12. Differentiate between in-situ and ex-situ conservation.
13. Explain global warming, ozone depletion and acid rain.
14. Describe the impacts of brick kilns and cement industries.
15. Explain tourism impacts and sustainable tourism alternatives.
16. Define sustainable development and explain its components.
17. Explain ecotourism and the key elements of EIA.
18. Write salient features of the Water Act, Air Act and Environment Protection Act.
19. Explain the Disaster Management Act, 2005.
20. Differentiate between Kyoto Protocol, Montreal Protocol, Ramsar Convention and CITES.

Last-Day Exam Strategy

• Memorise all definitions first.
• Learn causes, effects and control measures for every pollution topic.
• Practise at least two 7-mark answers from each unit.
• Use headings and numbered points in the examination.
• Underline keywords such as sources, impacts, prevention, control and importance.
• For Acts and conventions, remember the year and main objective.

UniversityScope
Learn • Prepare • Protect Our Planet

More Notes:
Air Pollution | Noise & Radiation | Water Pollution | Soil | Waste Management | Global Issues | Biodiversity | Regional Issues | Sustainable Development | Environmental Laws

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