Environment & Ecology (EVS) Essentials

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Unit-1: Environment & Ecosystem Environment Basics Definition: Sum total of social, economic, biological, physical, and chemical factors surrounding and influencing life. Types: Natural: Air, water, soil, land, forest, wildlife. Anthropogenic (Man-made): Agricultural fields, gardens, aquaculture. Components: Biotic: Living creatures (microbes, plants, animals, humans). Abiotic: Non-living/physical components (air, water, soil, rocks). Segments of Environment Atmosphere: Blanket of gases surrounding Earth. 78% Nitrogen, 21% Oxygen, 1% other gases. Layers: Troposphere: 0-11 km, weather changes, 99% water vapor. Stratosphere: 11-50 km, ozone layer. Mesosphere: 50-85 km, meteors burn, temperature to $-93^\circ C$. Thermosphere: 85-500 km, high temperature ($1200^\circ C$), ionized gases. Exosphere: Outermost, 700-10,000 km, merges into solar wind. Lithosphere: Earth's crust (silicates), mantle (Fe, Mg silicates), core (Fe). Hydrosphere: All water bodies. 97% oceans, 2% glaciers, 1% fresh water. Biosphere: Zone of air, soil, water supporting life; interactions of living organisms with environment. Scope and Importance of Environmental Studies Objectives: Awareness of environment & problems, understanding, concern, skill for solving problems, participation in protection. Scope: Ecosystems, natural resource conservation, pollution control, management, industry, research, social development, journalism, green advocacy. Programs: Environmental Education, Environmental Studies, Environmental Science, Environmental Engineering. Importance: Basic knowledge, understanding problems, resource conservation, ecological balance, sustainable development, public education, biodiversity protection. Multidisciplinary Nature Integrates biology, geology, chemistry, physics, engineering, sociology, health, anthropology, economics, statistics, computers, philosophy. Need for Public Awareness Unabated consumption of natural resources, pollution, disturbed ecological balance. Actions: Resource conservation, renewable energy, afforestation, moral codes, preserving green spaces, marine environment protection. Ecosystem Ecology: Study of organisms interacting with surroundings (coined by Earnst Haeckel, 1866). Ecosystem: Structural and functional unit of ecology (coined by A.G. Tansley, 1935). Interaction between organisms and environment. Definition: Natural unit of living and nonliving parts interacting to form a stable system. Types: Natural: Forest, grassland, desert, aquatic (pond, lake, river, ocean, estuary, wetland). Artificial: Crop field, garden, aquarium, dam. Structure of Ecosystem Abiotic Components: Non-living (air, water, soil, minerals, sunlight, temperature, nutrients, wind, altitude, turbidity). Biotic Components: Living (autotrophs, heterotrophs, saprotrophs). Producers (Autotrophs): Plants (photosynthesis). Consumers (Heterotrophs): Depend on others for food. Primary Consumers (Herbivores): Eat producers. Secondary Consumers (Carnivores/Omnivores): Eat primary consumers. Tertiary Consumers (Carnivores/Omnivores): Eat secondary consumers. Quaternary Consumers: Eat tertiary consumers, often top predators. Decomposers (Saprotrophs): Fungi, bacteria; thrive on dead organic matter, recycle nutrients. Balanced Ecosystem Efficient nutrient cycling, uninterrupted energy flow. Homeostasis: Tendency to resist change and maintain stability. Negative feedback: Counteracts changes to maintain balance. Positive feedback: Accelerates disturbances, can lead to system collapse. Functions of an Ecosystem Regulates ecological processes, supports life, provides stability. Cycles nutrients (biogeochemical cycles). Maintains trophic levels (food chain). Maintains biological diversity and stability. Development and evolution. Maintains energy flow. Homeostasis and feedback. Energy Flow in an Ecosystem 10% Law (Lindemann, 1942): About 10% of energy is transmitted from one trophic level to the next. Trophic Level Interaction: Food Chain, Food Web, Ecological Pyramids. Food Chain Transfer of food energy from producers to consumers through trophic levels. Example: Grasses $\rightarrow$ Grasshopper $\rightarrow$ Frog $\rightarrow$ Snake $\rightarrow$ Hawk/Eagle. Trophic Level: Each step in the food chain. Types: Grazing Food Chain: Starts with green plants, goes to decomposers (e.g., grassland, forest). Detritus/Parasitic Food Chain: Starts with dead organic matter (detritus feeders/decomposers). Linked to grazing food chain via waste. Food Web Interlocking pattern of various food chains. Consumers feed on multiple species. Provides more alternatives for food, increasing survival chances. Significance: Energy flow, nutrient cycling, population regulation. Biomagnification: Increase in concentration of non-biodegradable chemicals at successive trophic levels. Ecological Pyramid Graphical representation of trophic level structure and function. Producers at base, top carnivores at top. Types: Pyramid of Numbers: Total number of individuals at each trophic level. Can be upright or inverted (e.g., inverted for tree ecosystem). Pyramid of Biomass: Total biomass per unit area at each trophic level. Usually upright (land ecosystems), but can be inverted (aquatic, due to tiny phytoplankton). Pyramid of Energy (or Productivity): Represents energy available at each trophic level. Always upright due to energy loss at each transfer (10% law). Explains biomagnification. Ecosystem Restoration Recovery of degraded, damaged, or destroyed ecosystem by re-establishing structural characteristics, species composition, and ecological processes. Human Activities & Environment Food: Human consumption affects food webs (energy, agriculture, pollution, habitat destruction, overfishing, hunting). Overpopulation leads to food insecurity. Undernourishment: Lack of sufficient calories (below 90% of 2500 daily calories). Malnutrition: Deficiency of specific nutrients. Shelter: Increasing population pressure on land for housing. Unplanned settlements, pollution, resource depletion. Need for sustainable 'built environment'. Agriculture: Shift from hunter-gatherer to settled life (10,000-12,000 years ago). Intensive practices lead to: Land conversion & habitat loss. Wasteful water consumption (leaky irrigation, thirsty crops). Soil erosion and degradation. Pollution (pesticides, fertilizers, agrochemicals). Climate change (GHG from farming, livestock). Genetic erosion (loss of traditional varieties). Housing: Indoor Pollutants: AC (fungal growth), kitchen fumes (CO, SO$_2$), decorative materials (varnishes, paints). Outdoor Pollutants: Construction materials (water, soil pollution), photocopiers (ozone), tobacco smoke. Mining: Extraction of minerals. Methods: Open-pit, dredging, strip mining. Environmental Damage: Water pollution (chemicals, soil debris), deforestation, subsidence (land collapse), air pollution (hazardous gas), dangers to miners (lung diseases). Transportation and Industries: Emission/Air pollution: NO$_x$, CO$_2$, SO$_x$, particulates. Global warming: Major contributor of CO$_2$. Health impact: Respiratory issues, adverse pregnancy outcomes. Deforestation: For infrastructure (bridges, roads). Traffic congestion & urban sprawl. Noise Pollution: Vehicles, airplanes, trains. Economic and Social Security: Environmental impact of economic growth: Increased consumption, pollution, global warming, habitat loss. Social Security: Protection against common life risks (old age, disability, unemployment, etc.). Environmental Impact Assessment (EIA) Management tool for optimal resource use with cost-benefit analysis. Objective: Identify, predict, evaluate environmental impacts of projects and find remedies. "Widely accepted tool to ensure sustainable development with minimum environmental degradation." Steps: Screening $\rightarrow$ Scoping $\rightarrow$ EIA Report $\rightarrow$ Information & Consultation $\rightarrow$ Decision Making $\rightarrow$ Monitoring. Scope: Large projects (airports, shipyards), conservation of threatened species, landscape approach. Methods: Product environmental life cycle analysis, methods for GM plants, Fuzzy Arithmetic. Significance in India: Mandatory EIA clearance (MOEF), tool for environmental protection, guided by MOEF through State Pollution Control Boards. Drawbacks: Centralization (arbitrariness), no public participation, incomplete coverage of pollutants (noise, radiation). Sustainable Development Meets present needs without compromising future generations' ability to meet their own needs (Brundtland Report, 1987). Agenda 21: Global plan of action for sustainable development (UNCED Earth Summit, 1992). Conditions: Social Equity: Equilibrium within and between generations/nations. Economical Equity: Technology addressing developing countries' growth. Ecological Security: Protecting biodiversity, decreasing erosion, increasing forest area. Three Pillars of Sustainable Development Economic Viability Environmental Protection Social Equity Objectives of Sustainable Development Biodiversity conservation, population stabilization, renewable energy promotion, waste recycling/reuse, pollution control, forest cover increase, poverty elimination, environmental education, benefit to all. Measurement of Sustainability Environmental awareness, eco-friendly technology, individual/national/international will, cooperation. Challenges to Sustainable Development Modern lifestyle (electrical gadgets), energy-intensive industries, waste generation, pollution control technologies. Unit-5: Environment Protection Environmental Protection Act 1986 Enacted Nov 19, 1986. Empowers Central Government to protect and improve environmental quality, control pollution, restrict industrial operations. Background: Follows 1972 Stockholm Conference. Constitutional Provisions: Article 253 (international agreements), Article 48A (State's duty to protect environment), Article 51A (citizen's duty). Salient Features: Central govt powers, procedural safeguards for hazardous substances, entry & inspection powers, environmental labs, Govt Analyst appointment, penalties (up to 5 yrs imprisonment / 1 lakh fine), corporate offenses. Drawbacks: Centralization, no public participation, incomplete pollutant coverage (noise, radiation). Other Environmental Acts The Air (Prevention and Control of Pollution) Act, 1981: Control air pollution, establish CPCB/SPCB, set emission standards, designate air pollution areas. The Water (Prevention and Control of Pollution) Act of 1974: Control water pollution, maintain water purity. Vests regulatory authority in CPCB/SPCB, enforce effluent standards. The Wild Life (Protection) Act of 1972: Wildlife advisory boards, regulate hunting, establish national parks/sanctuaries, regulate trade. Prohibits hunting of Schedule 1 species. Various conservation projects (Project Tiger, Elephant, etc.). The Forest (Conservation) Act of 1980: Consolidate forest laws, regulate forest produce, allow states to declare reserved forests. Requires Central Govt approval for diversion of forest land. Role of Non-Governmental Organizations (NGOs) Legally constituted, voluntary, non-profit. Work at local/state/national/international levels. Initiatives: Environmental education, pollution prevention, forest protection, human health, afforestation, wildlife conservation, recycling, rural/eco development, population stabilization, renewable energy, biodiversity, organic agriculture, sustainable development. Examples: Kalpavriksh (KV), Kerala Sastra Sahitya Parishad, UNESCO, WWF. Human Population & Environment Population: Number of inhabitants in an area. Population Growth: Annual change in population size. Overpopulation: Human population exceeding Earth's carrying capacity. Causes of Overpopulation: Decline in death rate, agricultural progress, improved medical facilities, "more hands to fight poverty", immigration, inadequate family planning. Consequences: Resource depletion, environmental degradation, wars/conflicts, increased unemployment, expensive living, epidemics/pandemics, malnutrition/hunger/famine, reduced life expectancy, extinction of wildlife, increased intensive farming, rapid climate change. Solutions: Improved education (especially girl child), awareness of family planning, tax breaks/exemptions, sex education, social media marketing. Population Characteristics/Dynamics Exponential Growth: Population increases by a fixed percentage. Doubling Time: Years for population to double. Zero Population Growth (ZPG): Equal birth and death rates, stable population. Life Expectancy: Average years remaining for a living being. Population Pyramid: Graphical representation of age and sex. (Expanding, Constrictive, Stable). Replacement Level: Fertility level for exact population replacement without migration. Demographic Transition: Shift from high birth/death rates to low birth/death rates with development. Birth Rate: Live births per 1,000 population per year. Death Rate: Deaths per 1,000 population per year. Population Density: Population per unit area/volume. Infant Mortality Rate (IMR): Newborn deaths under one year per 1,000 live births. Environmental Education in India Scheme 'Environmental Education, Awareness and Training' (1983-84). Objectives: Promote awareness, spread education (non-formal), develop materials, promote through institutions, manpower development, NGO involvement, people's participation. Activities: National Environment Awareness Campaign (NEAC), Eco Clubs & National Green Corps (NGC), Global Learning & Observations to Benefit the Environment (GLOBE), Grants-in-Aid to Professional Societies. Women Education Empowers women, promotes self-worth, ability to determine choices, influences social change. Strengthens economies, reduces inequality, leads to healthy/productive lives, higher incomes, better futures. Crucial for achieving true equality and sustainable development. Unit-II: Natural Resources Natural Resources Life support materials from nature (water, air, soil, forests, minerals, crops). Classification: Basis Type Examples Origin Biotic Forests, animals, fossil fuels Abiotic Minerals, water, air, soil Renewability Renewable Solar, wind, hydro, biomass, geothermal, freshwater, forests, wildlife Non-renewable Fossil fuels, minerals, nuclear fuels Availability Perpetual Solar, wind, tidal, geothermal Non-perpetual Freshwater, forests, fish stocks, soil fertility Threats: Population growth, overuse/mismanagement of land, poor agricultural practices, pollution. Water Resources 71% Earth's surface covered by water. Availability: Saltwater (oceans): 97.5% (not directly usable). Freshwater: 2.5% Glaciers/Ice Caps: 1.74% of total (68.7% of freshwater). Groundwater: 0.66% of total (30.1% of freshwater). Surface Water: 0.03% of total (1.2% of freshwater) - lakes (0.007%), rivers (0.0001%), swamps/marshes (0.0008%). Hydrological Cycle: Solar energy drives evaporation; water returns as rain/snow, passes through organisms, returns to oceans. Global Water Crisis & Importance of Conservation: Limited availability & uneven distribution. Increasing demand (population growth). Climate change (altered rainfall, melting glaciers). Water pollution. Cost savings (reduces need for infrastructure). Over-exploitation of Water Resources: Groundwater depletion. Lowering of water table, increased pumping costs. Reduced surface water supplies. Land subsidence. Saltwater intrusion in coastal areas. Sustainable Use of Water Resources: Water recycling & reuse. Water-efficient appliances. Leak detection & repair. Rainwater harvesting. Desalination (reverse osmosis). Watershed management. Drip irrigation. Drought-resistant crops. Permeable pavements. Adjust watering schedules. Water Borne and Water Induced Diseases Water Borne Diseases: Caused by pathogenic microorganisms transmitted by contaminated freshwater consumption. Disease Pathogen Symptoms Cholera Vibrio cholerae (bacterium) Severe diarrhea, dehydration Typhoid Fever Salmonella typhi (bacterium) Fever, abdominal pain, diarrhea Dysentery Shigella spp. (bacteria) / Entamoeba histolytica (protozoan) Diarrhea with blood/mucus, abdominal pain Hepatitis A Hepatitis A virus Jaundice, fatigue, abdominal pain Giardiasis Giardia lamblia (protozoan) Diarrhea, abdominal cramps, nausea Water Induced Diseases: Caused by parasites/insects (vectors) that spend part of their life cycle in water. Disease Pathogen/Vector Transmission Symptoms Schistosomiasis Schistosoma spp. (parasites) Contact with freshwater (snails) Itching, rash, abdominal pain, fever Guinea Worm Disease Dracunculus medinensis Drinking contaminated water (water fleas) Painful ulcers, fever, rash Malaria Plasmodium spp. (parasites) Mosquitoes breeding in stagnant water Fever, chills, flu-like symptoms Dengue Fever Dengue virus Mosquitoes breeding in stagnant water High fever, severe headache, eye pain Chikungunya Chikungunya virus Mosquitoes breeding in stagnant water Fever, severe joint pain, rash Fluoride Problem in Drinking Water Importance: Preserves tooth enamel, prevents cavities. Optimal level: 0.7-1.2 mg/L. Sources of Pollution: Industries, mining, agricultural runoff, defluoridation residues, natural geological sources. Health Issues: Dental fluorosis (staining/mottling of enamel), Skeletal fluorosis (bones/joints discomfort, rigidity). Control/Prevention: Defluorination (bone charcoal, Nalgonda process using alum and lime). Arsenic Problem in Drinking Water Sources of Pollution: Natural (arsenic-rich rocks), food/drinking water, industry (glass, pigments, wood preservatives), agriculture (pesticides/fertilizers), tobacco smoking. Health Consequences: Acute: Vomiting, abdominal pain, diarrhea. Long-term: Pigmentation changes, skin lesions, hyperkeratosis (hard patches on palms/soles). Control/Prevention: Safe water supply, substitute low-arsenic sources (rainwater, treated surface water), mark high/low arsenic wells. Mineral Resources Inorganic, crystalline solids with specific chemical composition. (Quartz, feldspar, biotite). Use: Integral to development. Extracted via mining. Exhaustible and finite. Exploitation Consequences: Deforestation, desertification, species extinction, depletion of high-grade minerals, forced migration, soil erosion, greenhouse gas increase, pollution. Conservation: Reduce wastage, metal recycling, renewable alternatives, sustainable/planned use, advanced technology for low-grade ores, training miners. Biogeochemical and Natural Cycles Movement of elements/compounds between environment and living organisms. Maintains life-supporting processes. Carbon Cycle: Exchange of carbon (CO$_2$) between atmosphere, biosphere, oceans, geological formations. Gaseous (atmosphere-$\leftrightarrow$-reservoirs). Sedimentary (geological storage, release via volcanoes/weathering). Factors: Fossil fuel emissions, deforestation, respiration, decomposition, sedimentary rocks, ocean uptake, photosynthesis. Regulates Earth's climate. Sulphur Cycle: Movement of sulphur through air, water, soil, organisms. Deposition (SO$_2$ from volcanoes/fossil fuels). Assimilation (plants absorb sulfate from acid rain). Decomposition (release sulphur back to soil). Oxidation (bacteria convert sulfate to H$_2$S). Reduction (bacteria convert H$_2$S to sulfate). Critical for amino acids/vitamins, regulates soil/water acidity. Nitrogen Cycle: Nitrogen movement through atmosphere, soil, organisms. Nitrogen Fixation (N$_2$ to NH$_3$/NH$_4^+$ by bacteria/lightning). Nitrification (NH$_3$ to NO$_2^-$ then to NO$_3^-$ by nitrifying bacteria). Assimilation (plants absorb nitrates/ammonium). Consumption (animals eat plants). Ammonification/Decomposition (release NH$_3$ from dead organic matter). Denitrification (NO$_3^-$ to N$_2$ gas by denitrifying bacteria). Forest Resources Renewable resource, vital for economic development, provides products and food. Uses: Economical: Fuel wood, timber, non-timber products (resins, medicinal plants), ecotourism, jobs. Ecological: Oxygen, soil erosion control, biodiversity protection, water cycle regulation, climate regulation (CO$_2$ absorption), pollution reduction, microclimate control, noise control. Over-exploitation (Deforestation): Permanent destruction of forests. Causes of Deforestation: Shifting cultivation, commercial logging, fuel wood demand, agribusiness expansion, mining, development projects, raw materials for industry. Major Effects: Soil erosion, decreased rainfall, desert expansion, climate change, water table depletion, biodiversity loss, ecosystem disturbance. Remediation: Reforestation, afforestation, sustainable forest management, conservation. Case Study: Chipko Movement: Social-ecological movement (1970s, Uttarakhand) using non-violent resistance (hugging trees) against deforestation. Energy Resources Ability to perform work. Natural or human-made sources harnessed for power/heat. Classification: Criteria Category Definition Examples Origin Renewable Naturally replenished over short period Solar, Wind, Hydro, Biomass, Geothermal Non-Renewable Finite or long to replenish Fossil Fuels (Coal, Oil, Natural Gas), Nuclear (Uranium) Use/Development Conventional Widely used, traditional Coal, Oil, Natural Gas, Hydropower Non-Conventional Emerging or alternative Solar, Wind, Geothermal, Biofuels Conventional Energy Resources Coal: Formed 255-350 million years ago. India has 5% of world's coal. Advantages: Cost-friendly, easy to burn, high energy release, reliable. Disadvantages: High CO$_2$ (global warming), non-renewable, rapid depletion, harms ecosystem (mining). Petroleum: Formed from ancient sea animals. Extracted through drilling. Advantages: Easy/low-cost extraction, high density, easily transported, readily available infrastructure, broad applications, powers vehicles, constant power, powerful. Disadvantages: Limited resources, environmental pollution, hazardous substances, non-renewable, oil spills. Natural Gas: Primarily methane (95%). Often found with oil deposits. Most eco-friendly fossil fuel. CNG: Compressed Natural Gas (vehicle fuel). SNG: Synthetic Natural Gas (CO + H$_2$). Advantages: Environmentally clean, economical, convenient, safe, abundant, efficient, easy to deliver. Disadvantages: Limited quantities, highly combustible, non-renewable, emits CO$_2$, long processing, leakage risk. Nuclear Energy: High destructive power, also for commercial energy. Nuclear Fission: Splitting heavy nuclei (e.g., U-235) by neutron bombardment, chain reaction. Nuclear Fusion: Fusing light elements at high temperatures (e.g., H isotopes), releases enormous energy. Advantages: Carbon-free, small land footprint, high power, reliable. Disadvantages: Non-renewable uranium, high upfront costs, nuclear waste, catastrophic malfunctions. Wood: Renewable natural resource. Products: wood, paper, cellophane, rayon, plywood. 76% of Indian population uses wood for cooking, leading to deforestation. Advantages: Availability, low cost, environmentally friendly, sustainability. Disadvantages: Inconvenience, environmental concerns (deforestation, smoke), low carbon emission benefits. Non-Conventional Energy Resources Solar Energy: Capturing sunlight using technologies. Solar panels (photovoltaic cells): Sunlight $\rightarrow$ electricity. Solar thermal systems: Concentrated sunlight $\rightarrow$ heat fluid $\rightarrow$ steam $\rightarrow$ turbines $\rightarrow$ electricity. Devices: Solar cookers, dryers, water heaters, distillation. Advantages: Renewable, no by-products, free, efficient for heating/lighting, quiet, clean. Disadvantages: Expensive to build, intermittent (no sun at night/cloudy days). Biogas: Anaerobic digestion of organic materials (agricultural waste, food scraps, manure). Produces methane and CO$_2$. Advantages: Non-polluting (no smoke), reduces landfills, cheaper technology, generates employment, renewable. Disadvantages: Not efficient on large scale, contains impurities, unstable/hazardous (methane). Biofuel: Derived from biological materials (plants, algae, waste). Alternatives to fossil fuels. Bioethanol: From fermenting sugars (corn, sugarcane). Biodiesel: From vegetable oils/animal fats. Biogas: From anaerobic digestion. Advantages: Healthier population, cleaner environment, no hazardous gas emissions, reduces global warming risk. Disadvantages: Affects food supply/crop rotation, high labor/storage cost, high water consumption, increased demand for agricultural land. Hydrogen: Burns in air to form water, releases 150 kJ/g. High calorific value, non-polluting. Production: Thermal dissociation, photolysis, electrolysis of water; steam methane reforming. Advantages: Renewable, clean, non-toxic, efficient, powers spacecraft. Disadvantages: Expensive production, difficult handling/storage/transport, low availability in pure form, energy required for production. Wind Energy: Harnessing kinetic energy of wind with turbines. Advantages: No pollution, clean, free, renewable. Disadvantages: Intermittent, visual impact, noise disturbances, not near residential areas. Hydroelectric Energy: Using kinetic energy of flowing/falling water. Water stored in dams creates potential energy, flows through turbines, drives generators. Tidal Energy: Capturing ocean tide movement (tidal turbines, barrages/lagoons). Advantages: Renewable, less GHG than fossil fuels, reliable, steady power, water supply/storm control/farming uses, long-lasting plants. Disadvantages: Dams harm aquatic environments/fish/wildlife, large areas flooded, costly construction, energy production affected by droughts, dam failures can cause floods. Geothermal Power: Harnessing Earth's heat energy. Hot rocks heat water to produce steam for turbines. Advantages: No harmful by-products, self-sufficient, small landscape effect, low cost. Disadvantages: Pollutants if constructed incorrectly, hazardous minerals/gases released by drilling, suitable only in specific regions, prone to earthquakes/volcanoes, huge installation cost. Unit-III: Environment Pollution Environmental Pollution Definition: Undesirable change in physical, chemical, or biological characteristics of environment components, causing harmful effects. Derived from French "polluere" (to soil/defile). Pollutants: Components of pollution (foreign substances/energies or natural contaminants). Types: Air, Water, Soil, Marine, Noise, Thermal, Solid Waste, Radioactive pollution. Air Pollution Atmospheric condition where substances (gases, solids, liquids) are in concentrations causing undesirable effects. Causes: Natural: Cyclones, earthquakes, volcanic eruptions (dust/ash), forest fires, pollen, microbes, decaying organic matter. Man-Made: Automobiles, domestic cooking, deforestation, population, industrialization, construction, pesticides. Types of Pollutants: Primary: Released directly (PM, CO$_x$, NO$_x$, SO$_x$). Secondary: Formed from primary pollutants (Ozone, SO$_3$, H$_2$SO$_4$, HNO$_3$). Gaseous: SO$_x$, NO$_x$, carbon oxides, VOCs. Particulate: Smoke, dust, soot, fumes, aerosol, liquid droplets, pollen. Radioactive: Radon 222, Iodine 131, Strontium 90. Indoor: Radon gas (from building materials), CO, SO$_2$, HCHO, BAP (from burning fuel/cigarette smoke). Common Air Pollutants & Effects Carbon Monoxide (CO): Colorless, odorless, tasteless. Sources: Incomplete fossil fuel combustion (motor vehicles), industrial operations, volcanoes. Effects: Reduces oxygen-carrying capacity of blood (forms carboxyhemoglobin), headaches, laziness, coma, brain damage, death. Control: Engine modification (fuel-air ratio), use cleaner fuels, catalytic converters. Nitrogen Oxides (NO$_x$): NO, NO$_2$. Sources: Lightning, fossil fuel burning (industries, power plants), acid manufacturing. Effects: NO$_2$ forms photochemical smog, acid rain (corrodes marble/metals), respiratory irritant (bronchitis). Control: Engine modification (reduce excess air), flue gas scrubbing, selective catalytic reduction. Sulphur Oxides (SO$_x$): SO$_2$, SO$_3$. Colorless, irritating gas. Sources: Volcanic eruptions, petroleum refining, copper smelting, cement plants, fossil fuel burning. Effects: Acid rain (corrodes buildings/metals), respiratory irritant (bronchitis, death), rots wool/cotton/leather, makes paper brittle, chlorosis in plants. Control: Low sulfur fuel, chemical scrubbers (limestone, citric acid). Particulate Matter (PM)/Suspended Particulate Matter (SPM): Dispersed solid/liquid in air (0.002-500 $\mu$m). Types: Aerosol, dust, fumes, mist/fog, smoke/soot, fly ash. Sources: Volcanic eruptions, dust storms, burning coal/diesel, agriculture, unpaved roads, construction. Composition: Organic (PAH), Inorganic (iron oxide, lead halides, asbestos). Effects: Nose/throat irritation, lung damage, bronchitis, asthma, reproductive problems, cancer, reduced visibility, acid deposition. Control: Gravity settling chamber, cyclone collector, filters, scrubbers. Hydrocarbons: Low molecular weight, gaseous/volatile liquid. Sources: Decaying vegetation, trees, motor fuels, evaporating paints. Effects: Carcinogenic, photochemical smog, mucus membrane irritation, narcotic effects, plant toxicity. Control: Thermal/photochemical decomposition, adsorption/absorption/incineration, fuel induction systems. Environmental Effects of Air Pollution Human Health: Acute: Headaches, colds, irritated throats, coughs, eye irritation, bronchial spasm. Chronic: Lung cancer, shortness of breath, asthma, chronic bronchitis, emphysema. CO causes suffocation (carboxyhemoglobin). Benzene, formaldehyde, PCBs, toxic metals, dioxins cause mutations, reproductive problems, cancer. Plants: Enters through stomata, destroys chlorophyll, affects photosynthesis, erodes cuticle. Causes necrosis, chlorosis, epinasty, abscission. Aquatic Life: Acid rain lowers pH in lakes, affects fish. Materials: Corrosion of metals (H$_2$SO$_4$), damage to marble/limestone, rots leather/fabric, embrittles paper. Ozone causes rubber cracking. Control of Air Pollution Source Control: Unleaded petrol, low sulfur/ash fuels, public transport, plant trees, industries outside city, catalytic converters. Industrial Centers: Restrict emissions, incorporate control equipment, continuous monitoring. Control Devices: Gaseous: Absorption, adsorption, condensation, incineration. Particulate Matter: Gravitational settling, cyclone separators, fabric filters, electrostatic precipitators, wet scrubbers. Water Pollution Presence of foreign impurities in water, causing health hazards, lowering quality, making it unfit for use. Causes: Natural: Soil erosion, decaying plants/animals. Man-Made: Sewage, industrial waste, agricultural waste, human activities, traditions, radioactive discharges. Sources: Point Source: Discharged at specific locations (pipes, ditches, sewers). Regulated by law. Non-point Source: Cannot be traced to single point (runoff, pesticides, acid rain). Classification of Pollutants: Suspended Matter & Sediments: Silt, sand, minerals. Causes siltation, cloudy water, blocks sunlight, disrupts food chain, carries harmful substances. Oxygen Demanding Wastes: Biodegradable organic compounds (sewage, food processing). Depletes dissolved oxygen (DO), kills aquatic life if DO Heat/Thermal Discharge: Hot water from power plants. Reduces DO, makes organisms vulnerable, thermal shock. Infectious Agents/Pathogens: Bacteria, viruses, fungi, protozoa (from sewage, slaughterhouses). Cause cholera, typhoid, polio. Synthetic Organic Chemicals: Pesticides, detergents, pharmaceuticals, plastics. Toxic, bio-refractory, nervous system damage, cancer, harms wildlife. Inorganic Chemicals: Heavy metals, mineral acids, salts. Non-biodegradable. Unusable water, skin cancer, nervous system damage, harms aquatic life, lower crop yields, corrosion. Inorganic/Plant Nutrients: Nitrogen, phosphorus (from agriculture, fertilizers, sewage). Causes eutrophication, depletes DO, kills fish. Excess nitrates in drinking water reduce blood's oxygen-carrying capacity. Radioactive Waste: Mining, processing, nuclear plants, weapons testing. Causes genetic mutations, birth defects, cancers. Accumulates in thyroid, liver, bones. Oil: Natural product from fossilized plant remains. Oil spills, leaks. Complex hydrocarbons, biodegradability varies. Control Measures of Water Pollution Non-point Sources: Judicious use of agrochemicals, nitrogen-fixing plants, integrated pest management, prevent manure runoff, separate sewage/rainwater drainage, planting trees. Point Sources: Wastewater treatment (primary, secondary) to reduce BOD/COD. Bioremediation: Using microorganisms to degrade pollutants. Waste Water Treatment/Sewage Treatment Process of cleaning pollutants from wastewater to make it safe. Methods: Physical, chemical, biological. Steps: I. Preliminary/Physical Treatment: Remove gross solids, grits, fats. Screening: Removes large solids. Grit removal: Removes small, non-biodegradable particles. Skimming: Removes fatty/oily material. II. Primary Treatment: Remove suspended solids, reduce organic matter. Sedimentation: Solids settle at bottom (removes 90% suspended solids, 40% organic matter). Mechanical flocculation: Rotating paddles to form larger solids. Chemical flocculation: Adding coagulants (alum) to form precipitates. Neutralization: Adjust pH for microbial growth. III. Secondary Treatment: Remove dissolved/colloidal organic matter using microorganisms. Reduces BOD. Trickling filter: Effluent sprayed over filter bed with zoogleal layer (bacteria, algae). Oxidizes organic matter. Activated sludge system: Sewage mixed with activated sludge (microorganisms), aerated to oxidize organic compounds. Sludge settles, some returned as inoculum. IV. Tertiary/Final Treatment: Remove chemical/biological agents before discharge. Removal of suspended solids: Microstraining, chemical coagulation + filtration. Removal of dissolved solids: Adsorption by activated carbon, reverse osmosis. Removal of nitrate/phosphate: Biological process (nitrifying and denitrifying bacteria). Killing microorganisms: Disinfection (chlorination). Soil Pollution / Land Pollution Contamination of soil by human/natural activities, causing harm to living beings. Components: Organic mineral matter (45%), Organic matter (5%), water (25%), air (25%). Evolution of Soil: Physical weathering $\rightarrow$ chemical weathering $\rightarrow$ biological phase. Causes: Industrial Wastes: Pulp/paper mills, chemical factories, refineries. Affects chemical/biological properties, enters food chain. Urban Wastes: Commercial/domestic waste (garbage, rubbish, plastics, glass, metals). Not easily degraded. Agricultural Practices: Fertilizers, pesticides, herbicides, weedicides, farm wastes. Radioactive Pollutants: Nuclear testing, industries. Radium, Th, U, K-40, C-14. Biological Agents: Human/animal/bird excreta. Heavy application of manures damages plants. Effects: Affects human health, reduces soil fertility/productivity, causes abnormalities (radio-isotopes replacing elements), eutrophication (N/P runoff), groundwater contamination. Control Measures: Control soil erosion (forestry/farm practices, contour cultivation, terracing, reduced deforestation). Proper waste dumping (controlled tipping). Production of natural fertilizers (bio-pesticides, organic fertilizers, compost). Proper hygienic conditions. Public awareness/environmental education. Recycling and reuse of wastes. Ban on toxic chemicals (DDT, BHC), nuclear explosions. Microbial degradation, biogas generation. Noise Pollution Unwanted, unpleasant sound causing discomfort. Measured in decibels (dB). Types: Industrial Noise: High intensity, from machines (factories, mills). Transport Noise: Road, rail, aircraft. Increased vehicular noise. Neighborhood Noise: Household gadgets, community (TV, radios, loudspeakers). Sources: Industrial units, transportation, construction, celebrations, home appliances. Effects: Physiological: Blood vessel contraction, high blood pressure, heart attacks, neurological problems, birth defects, muscle contraction, nervous breakdown. Auditory: Impairment of hearing, chronic damage to inner ear. Other: Mental distress, dizziness, unconsciousness, impaired night vision, decreased color perception. Control: Source Control: Acoustic treatment, design changes, limiting operation times. Transmission Path: Sound insulating enclosures, noise barriers, sound absorbing materials. Receptor Control: Alter work schedules, ear plugs. Oiling machines. Preventive Measures: Noise limits for vehicles, ban honking, silence zones, redesign buildings, reduce traffic, mass public transport. Solid Waste Management Waste: Unwanted or useless materials. Types of Wastes: Biomedical, Commercial, Chemical, Biodegradable, Animal By-Product, Gaseous, Liquid, Solid. Solid Waste: Non-liquid, non-soluble materials (municipal garbage, industrial waste, dead animals, demolition). Types of Solid Waste: Municipal Solid Waste (MSW): Household, construction debris, sanitation residue, street waste. Industrial Waste: Hazardous (toxic, corrosive, inflammable, explosive). From metal, chemical, paper, pesticide industries. Bio-Medical Waste: From diagnosis, treatment, immunization (sharp waste, pathological, pharmaceutical, genotoxic, chemical, radioactive). Effects of Solid Waste: Health hazard (diseases like cholera, typhoid, plague), environmental impact (odour, decomposition, putrefaction). Waste Management (3Rs): Reduce: Minimize use of disposable goods. Reuse: Use items multiple times (containers, shopping bags). Recycle: Process waste materials into new products. Methods of Waste Disposal: Landfill: Waste spread in thin layers, covered with soil. Used for non-reusable/recyclable waste. Composting: Organic waste decomposes under microbial action to form nutrient-rich manure. Vermicomposting: Using worms to degrade organic matter into nutrient-rich manure. Waste Compaction: Compressing waste (cans, plastic) into blocks for recycling. Biogas Generation: Biodegradable waste converted to biogas (fuel) by microbial degradation (aerobic/anaerobic). Incineration: Controlled combustion to reduce waste to ash/gas. Heat can generate electricity. Pyrolysis: Thermal degradation of waste in absence of air, producing char, oil wax, combustible gases. Unit-IV: Current Environmental Issues of Importance Greenhouse Effect and Global Warming Greenhouse Effect: Natural process where atmospheric gases (CO$_2$, ozone, methane, N$_2$O, CFCs, water vapor) trap heat in troposphere. Keeps Earth at $15^\circ C$. Enhanced Greenhouse Effect: Human activities increase GHG concentration, leading to global warming. Greenhouse Gases: Carbon Dioxide (CO$_2$): 55% of human-caused GHGs. From fossil fuels (67%), land destruction/burning (33%). Atmospheric lifetime: 500 years. Chlorofluorocarbons (CFCs): 24% of human-caused GHGs. From refrigerators, ACs, solvents, plastic foams, aerosols. Trap 1500-7000x more heat than CO$_2$. Deplete ozone layer. Methane: 18% of GHG rise. From anaerobic decomposition (swamps, paddy fields, landfills), cattle, natural gas/oil production. Traps 25x more heat than CO$_2$. Nitrous Oxide (N$_2$O): 6% of human-caused GHGs. From nitrogen fertilizers, livestock manure, biomass burning. Traps 230x more heat than CO$_2$. Depletes ozone layer. Impacts of Greenhouse Effect/Global Warming: Rise in Global Temperatures: Predicted 1.5-5.5$^\circ C$ by 2050. Sea Level Rise: Thermal expansion of water, melting ice sheets/glaciers. Submerges coastal areas, affects agriculture, disturbs spawning grounds. Effects on Human Health: Disrupts rainfall, affects vector-borne diseases (malaria), worsens respiratory/skin conditions. Impacts on Agriculture: Varied effects on crops, detrimental in tropical/subtropical regions, increased pests/diseases. Preventive Measures: Reduce CFC/fossil fuel use, energy efficiency, renewable energy, nuclear power, switch from coal to natural gas, methane capture, reduce meat production, sustainable farming, population control, CO$_2$ capture, afforestation, photosynthetic algae. Climate Change Average change in weather conditions (temperature, precipitation, humidity) over $\ge 30$ years. Causes: Natural: Volcanic activity (CO$_2$, ash), changes in Earth's orbit (eccentricity, axial tilt, precession affecting solar radiation). Anthropogenic: Increased GHG concentrations (CO$_2$, CH$_4$, N$_2$O, O$_3$, H$_2$O, CFCs, HFCs) from fossil fuels, industries, automobiles, agriculture, land-use change after Industrial Revolution. Impacts: Non-uniform temperature change (poles warm more), disturbed global wind/ocean currents, altered rainfall patterns (some areas wetter/drier), increased evapotranspiration, ecosystem shifts (species migration, extinction), increased erosion. Acid Rain Rainfall with pH $\le 5.6$ due to chemical reaction of SO$_2$ and NO$_x$ with atmospheric water vapor. Coined by Robert Angus Smith (1872). Forms: Wet deposition (rain) or dry deposition (dry particles of sulfuric/nitric acid). Formation: SO$_2$ (coal burning, industries, smelters) and NO$_x$ (motor vehicles) combine with moisture. Harmful Impacts: Soil: Leaches nutrients, slows soil organism breathing, increases ammonia, decreases nitrates. Less effect on alkaline Indian soils. Animal Life: Indirect effects (releasing metals into water), impacts reproduction/survival. People: Bad smells, poor visibility, skin/eye/lung irritation, chronic bronchitis, emphysema, cancer, heavy metal concentration, acidic fog. Monuments & Buildings: Deteriorates stone, rusts metal. Breaks down calcium-based materials. Control: Reduce SO$_2$ from coal-fired plants (low sulfur coal, "washing" coal, scrubbers), change burning methods for NO$_x$. Ozone Layer Natural sunscreen in stratosphere, filters harmful UV radiation. Ozone (O$_3$) formed from O$_2$ by UV radiation. Formation: O$_2$ + h$\nu$ $\rightarrow$ O + O; O + O$_2$ + M $\rightarrow$ O$_3$ + M. Absorption: O$_3$ + h$\nu$ $\rightarrow$ O$_2$ + O. Ozone Layer Depletion Thinning of ozone layer due to Ozone Depleting Substances (ODS). Major ODS: CFCs (refrigerants, aerosols), halons (fire retardants), carbon tetrachloride (solvents), methyl bromide (pesticides), methyl chloroform (solvents). Mechanism: Chlorine/bromine from ODS catalytically destroy ozone. Cl + O$_3$ $\rightarrow$ ClO + O$_2$ ClO + O $\rightarrow$ Cl + O$_2$ (one Cl destroys ~100,000 O$_3$ molecules). Effects: Increased UV-B radiation (DNA damage, mutations, skin cancer, cataracts), immuno-suppression, decreased phytoplankton (affects aquatic food chain), decreased crop yield, degradation of plastics/polymers. Protection: Vienna Convention (1985) & Montreal Protocol (1987): Agreements to phase out ODS. Kigali Amendment (2016): Reduce HFCs (non-ODS GHGs). Automobile Pollution Introduction of dangerous materials into environment by motor vehicles. Components: Ozone: Component of urban smog (from hydrocarbons + NO$_x$ + sunlight). Irritates respiratory system. Particulate matter: Soot, metal, pollen. Penetrates lungs. Nitrogen oxides: Irritate lungs, decrease defense against respiratory diseases, contribute to ozone/particulate pollution. Carbon monoxide: Odorless, colorless gas from fossil fuel combustion. Prevents oxygen from reaching organs. Sulfur dioxide: From sulfur-containing fuels (diesel). Health concern for children/asthmatics. Hazardous air pollutants: Chemical substances from cars, refineries, gas pumps. Causes: Increasing number of automobiles, 2-stroke engines, low fuel quality, obsolete cars, insufficient maintenance, heavy traffic, bad roads, outdated technology. Effects: Climate change (GHG, ozone depletion), poor air quality, international standing, well-being (lung infections, cancer, heart disease, asthma), travel/tourism impact, acid rain & smog. Solutions: Alternate fuels, complete fuel combustion, catalytic converters, engine efficiency, replace internal combustion engines, citizenship education, policies, automobile maintenance, dispose old cars, car sharing. Paddy Straw Burning Burning of rice straw after harvest, especially in Punjab/Haryana, due to insufficient time before wheat sowing. Cost-effective but harmful. Case Study: NGT banned crop residue burning (2015). Despite fines, farmers continue. Environmental & Health Concerns: Air pollution (CO$_2$, CO, SO$_x$, PM, black carbon), contributes to Delhi haze, Himalayan glacier melt. Soil temperature rise, kills bacteria/fungi, reduces organic quality, depletes macronutrients (N, P, K, Ca, Mg) and micronutrients (Fe, Mn, B, Zn, S). Health problems: Eye/nose/throat irritation, coughing, wheezing. Increases evaporation rate. Solutions: National Policy for Crop Residue Management (2014), alternative uses (calf feed, compost, roofing, biomass energy, mushroom culture, paper, biofuel), conservation agriculture, agricultural machinery (Happy Seeder, Rotavator, No-till seed drill, Baler, Chopper, Reaper Binder) with government subsidies.