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Edit Comment Close Premium member Presentation Transcript PowerPoint Presentation: UNIT II ENVIRONMENTAL POLLUTION Presentation By Jhansirani.R AP/ECEPowerPoint Presentation: Syllabus Definition Causes, effects and control measures of: (a) Air pollution (b) Water pollution (c) Soil pollution (d) Marine pollution (e) Noise pollution (f) Thermal pollution (g) Nuclear hazards Solid waste management: causes, effects and control measures of municipal solid wastes Role of an individual in prevention of pollution Pollution case studies Disaster management: Floods, Earthquake, Cyclone, and Landslides.PowerPoint Presentation: Definition: Any undesirable change in the physical, chemical, or biological characterstics of any component of the environment (Air, Water, Soil ) which can cause harmful effects on various forms of life or property. Types: (a) Air pollution (b) Water pollution (c) Soil pollution (d) Marine pollution (e) Noise pollution (f) Thermal pollution (g) Nuclear hazardsAir pollution : Air pollutionAir pollution: Air pollution Definition: It is an atmospheric condition in which certain substance are present in excess concentration which can cause undesirable effects on man and his environment. These substances includes gases, particulate matter, radioactive substances etc.,Air pollution: Air pollution Gaseous pollutants: Oxides of sulphur (SO 2 , SO 3 ) Oxides of nitrogen (NO, NO 2 , NO x ) Carbon monoxide (CO) Volatile organic compounds (hydrocarbons) Particulate Pollutants: Smoke, Dust, Fumes Aerosols Liquid droplets Pollen grainsAir pollution: Air pollution Radioactive pollutants: Radon – 222 Iodine – 131 Strontium – 19 Plutonium – 239Classification of air pollution: Classification of air pollution On basis of origin of pollutants they can be classified as Primary Pollutants: They are emitted directly into the atmosphere by the sources (such as power-generating plants). Eg: CO, NO x , SO x , Hydrocarbons, radioactive substances etc., Secondary Pollutants: These are formed as a result of reactions between primary pollutants and other elements in the atmosphere Eg: ozone (O 3 ), peroxyacetyl nitrate (PAN), photochemical Smog etc.,.Causes/sources of Air pollutants: Causes/sources of Air pollutants Natural sources: Volcanic eruptions Forest Fires Sea salt sprays Biological Decay Photochemical oxidation of terpenes marshes Extra terrestrial bodies Pollen grains of flowers, spores Radioactive minerals present in earth crustCauses/sources of Air pollutants: Causes/sources of Air pollutants Man made sources: Thermal power plants Industrial units Vehicular emissions Fossil fuel burning Agricultural activities Thermal power plants is the major sources for generating electricity in India The main pollutants emitted are fly ash, SO 2Causes/sources of Air pollutants: Causes/sources of Air pollutants Metallurgical plants also consume coal and produce similar pollutants Fertilizer plants, smelters, textile mills, tanneries, refineries, chemical industries, paper and pulp mills are other sources of air pollution Automobile exhaust is another major sources of air pollution Automobiles release gases such as - CO (77%) - Oxides of nitrogen (8%) - Hydrocarbons (14%)Causes/sources of Air pollutants: Causes/sources of Air pollutants Heavy duty diesel vehicle spew more No x and particulate matter than petrol vehicles which produce more carbon monoxide and hydrocarbonsIndoor air pollution: Indoor air pollution Radon gas: They are responsible for lung cancer deaths Radon can be emitted from building materials like bricks, concrete, tiles etc., which are derived from soil containing radium Radon is also present in ground water and natural gas and is emitted indoors while using themPowerPoint Presentation: Many houses in under-developed countries including India use fuels like coal, dung-cakes, wood and kerosene in kitchens. Complete combustion of fuel produces carbon dioxide which may not be toxic Incomplete combustion produces the toxic gas carbon monoxide Coal contains varying amount of sulphur which on burning produces sulphur dioxide Fossil fuel burning produces black sootPowerPoint Presentation: The pollutants like CO, SO2, formaldehyde, benzo-(a) pyrene (BAP) are toxic and harmful for health. BAP is also found in cigarette smoke and it causes cancer A housewife using wood as fuel for cooking inhales BAP equivalent to 20 packets of cigarette a day. Indoor air pollutionEffects on Human health: Effects on Human health H uman respiratory system has a number of mechanism for protection from air pollution Bigger particles can be trapped by the hairs and sticky mucus in the lining of the nose . Smaller particles can reach tracheobronchical system and there get trapped in mucus . They are sent back to throat by beating of hair like cilia from where they can be removed by spitting or swallowing.PowerPoint Presentation: Years of exposure to air pollutants (including cigarette smoke) adversely affect these naturals defenses and can result lung cancer , asthma, chronic bronchitis and emphysema (damage to air sacs leading to loss of lung elasticity and acute shortness of breath.) suspended particulates can cause damage to lung tissue and diseases like asthma ,bronchitis and cancer especially when they bring with them cancer causing or toxic pollutants attached on their surface.PowerPoint Presentation: Sulphur dioxide(so 2 ) causes constriction of respiratory passage and can cause bronchitis like conditions. In the presence of suspended particulates, So 2 can form acid sulphate particles, which can go deep into the lungs and affect them severely. Oxides of nitrogen especially NO2 can irritate the lungs and cause conditions like chronic bronchitis and emphysema,PowerPoint Presentation: Carbon monoxide(co) reaches lungs and combines with hemoglobin 210 times more than oxygen. Hemoglobin is, therefore unable to transport oxygen to the various parts of the body This causes suffocation, long exposure to CO may cause dizziness, unconsciousness and even deathPowerPoint Presentation: Benzene (from unleaded petrol) formaldehyde and particulates like polychlorinated biphenyls toxic metals and dioxins (burning of polythene) can cause mutation, reproductive problems or cancer Asbestos, Beryllium, Mercury, Arsenic and Radioactive substances cause lung diseases and affect other vital organs like kidney, liver, spleen, brain & some cause cancerEffects on Plants: Effects on Plants Air pollution affects plants by entering through stomata (leaf pores), destroy chlorophyll and affect photosynthesis During day time the stomata are wide open to facilitate photosynthesis hence pollutants affect them more during day time Pollutants also erode waxy coating of the leaves called cuticle Cuticle prevents excessive water loss and damage from diseases, pests, drought and frostEffects on Plants: Effects on Plants Damage to leaf structure causes Necrosis (dead areas of leaf) Chlorosis (loss of chlorophyll causing yellowing) Epinasty (downward curling of leaf) Abscission (dropping of leaves) Particulates on leaves can form encrustations and plug the stomata and reduce the availability of sunlight, which results in death of the plant.PowerPoint Presentation: So 2 causes Bleaching of leaves Chlorosis Injury Necrosis of leaves NO 2 causes Increased abscission and suppressed growth O3 causes Flecks on leaf structure Premature aging Necrosis BleachingPowerPoint Presentation: Preoxyacetyl nitrate (PAN) causes Silvering of lower surface of leaf Damage to young and sensitive leaves Suppressed growth Fluorides causes Necrosis of leaf tip Ethylene results in Epinasty Leaf abscission, Dropping of flowersEffects on Aquatic life: Effects on Aquatic life Air pollutants mixing up with rain can cause high acidity (lower pH) in fresh water lakes This affects aquatic life especially fish Some of the fresh water lakes have experienced total fish death.Effects on materials: Effects on materials Particulates causes damage to exposed surfaces So 2 and moisture causes corrosion of metallic surfaces due to formation of sulfuric acid Metal parts of buildings, vehicles, bridges, wires & railway tracks are affected Sulfuric acid causes disfigurement of statues made of marble & limestone Sulfuric acid damages leather binding of booksEffects on materials: Pages of books also becomes brittle So 2 can affect fabric, leather, paint & paper Ozone causes cracking of rubber Nylon stockings are weakened and damaged Tyres of vehicles also damaged Oxides of nitrogen & ozone causes fading of cotton and rayon fibers Effects on materialsCONTROL OF AIR POLLUTION: CONTROL OF AIR POLLUTION Siting of industries after proper environmental impact assessment studies By dilution of emission This can be done by increasing of stack height beyond inversion layer Minimize activities which causes pollution like transpotation & energy production Modification of process and/or equipmentsPowerPoint Presentation: Use of appropriate material Using low sulphur coal in industries Removing sulphur from coal Removing NOx during the combustion process and controlling the flow of air & fuel in industrial boilers Vehicular population can be checked by regular tune-up of engines Replacement of more polluting old vehicles, Installing catalytic convertersPowerPoint Presentation: By engine modification to have fuel efficient mixtures to reduce CO and hydrocarbon emission Slow & cooler burning of fuels to reduce Nox emission Using mass transport system, bicycles etc., Shifting to less polluting fuels Using non-conventional source of energy Using biological filters and bio-scrubbers Planting more trees Reduction of pollution at sourceWhat Can You Do? : Reduce vehicle emissions: Drive less Keep cars well maintained and tires properly inflated Turn off the engine when your vehicle is not in motion Purchase low-emitting and fuel efficient vehicles Share a ride, take public transportation bike, or walk Cut your grass after 6 p.m. Refuel your car after 6 p.m. Combine errands into one trip What Can You Do?Reduction of air pollution at source: Reduction of air pollution at source Gaseous pollutants: They can be reduced by physical adsorption on porous solid materials like activated charcoal, silica gel, Fullers earth etc., Effluent gases can be absorbed in liquid absorbent Eg: SO2 absorbed in ammonia solution They can be removed by condensation which is carried out by cooling medium in tubes where the gases in contact condense and can be collected thereafterPowerPoint Presentation: Combustion can be used to reduce pollution by burning the pollutants in combustion equipment at optimal conditions of oxygen and temperature. Particulate matter: Many devices are available now-a-days, choice of which depends on characteristics of particulate, flow rate, collection efficiency, costs etc., Cyclone separator Baghouse filter Wet scrubber Electrostatic precipitatorsCyclone separator: Cyclone separator It consist of a cylinder with an inverted cone attached at the bottom Dirt gas enters tangentially at the top of the cylinder & spins forming a vortex Due to centrifugal force, the particles strike the wall of the cylinder The particles then fall in the hopper due to gravity from where they are removed.Cyclone separator: Cyclone separator The spinning gas forms an inner vortex and leaves from the top The cyclone is very efficient for larger particles Smaller particles are not removed efficiently Therefore cyclones are employed before the use of other costly devicesBag house filter: Bag house filter It contains a large number of filter bags made of fabric They are hung upside down in several compartments of bag house filter Dirty gas is passed through the filter bags which leaves the bags through their pores Dust particles get deposited on the inner surface of the bag filters and forms a cake which can be removed by shaking Efficient for removal of very small particles It is expensive and cannot be operated for moist gases Corrosive gases may damage the material of the bagWet scrubbers: Wet scrubbers Dirty gases are passed through water in the chamber or water is sprayed on the gas Particles are made wet and are removed from the gas stream which leaves from the top of the scrubber Efficient for removing the particulates Used for removal of toxic and acidic gases also.Electrostatic precipitator parallel plate type: Electrostatic precipitator parallel plate type Dust discharge Clean gas Electrodes Dirty gasElectrostatic precipitator: Electrostatic precipitator Vertical wires are placed between the parallel plates or wire is hung along the axis of the cylinder High negative voltage is applied to the wire Dust particles while passing from the lower end get negatively charged (ionized) and are collected on the positively charged surface (plates/cylindrical body) Clean gas leaves from the top Dust particles fall down in the dust collector or removed by scrapping or by liquids Can efficiently remove even submicroscopic particlesElectrostatic precipitator wire and pipe type : Electrostatic precipitator wire and pipe type You do not have the permission to view this presentation. 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