air pollution

: Air pollution is the presence of substances in ambient atmosphere, generally resulting from the activity of man in sufficient concentration, present for sufficient time and cause harmful effect on humans, plants and animals.

1. Content…. What is air pollution? Composition of air Structure of atmosphere Ambient Air Quality Standards Classification of air pollutants Sources of common air pollutants like PM, SO 2 , NO X , Natural & Anthropogenic Sources Effects of common air pollutants

2. Definition: Air pollution is the presence of substances in ambient atmosphere, generally resulting from the activity of man in sufficient concentration, present for sufficient time and cause harmful effect on humans, plants and animals.

3. Composition of air

4. Composition of air

5. Structure of atmosphere

6. Classification of air pollutants Based on origin of air pollutants: Primary Pollutant - chemical , that occurs in a harmful concentration , added directly to the air by natural events or human activities eg . Sulphur oxides, nitrogen oxides Secondary Pollutant - harmful chemical formed in atmosphere when a primary air pollutant reacts with the normal air components or with other air pollutants eg . ozone, sulphur trioxide

7. Classification of air pollutants Primary Pollutants Most hydrocarbons Most suspended particles CO 2 CO SO 2 NO 2 NO Most NO 3 – and SO 4 2– salts Secondary Pollutants PANs SO 3 H 2 SO 4 HNO 3 O 3 H 2 O 2 Stationary Mobile Natural Sources

8. Based on state of matter, air pollutants: Gaseous pollutants: Pollutants are gaseous in state at normal temperature and pressure. eg . Common gas pollutants like CO, CO 2 , NO X , SO X . Particulate air pollutants: Suspended droplets, solid particles or their mixtures in the atmosphere, commonly referred as particulates. eg . Dust, smoke, aerosols.

9. Sources of Air pollution Natural: Pollen grains Volcanoes Forest fire Salt spray from oceans Dust storms Marshy land Bacteria and other microorganisms Spores Photochemical reactions

10. Sources of Air pollution Man made: Industrial unit Thermal power plants Automobile exhaust Fossil fuel burning Agricultural activities Mining Air crafts Nuclear explosion Domestic burning of woods

11. Sources of Air pollution Man made: Point or Stationary sources - those that are fixed in location. point sources e.g. smoke stacks, 14% air pollution from plants generating electricity Line or Mobile sources - those that move while polluting, e.g. trucks, cars, busses etc. 60% of air pollution from motor vehicles. area sources: town or cities add smoke and gases over wide areas called area sources of air pollution.

12. Point or Stationary sources Line or Mobile sources

13. Sources of common air pollutants Particulate matter: Small, solid particles and liquid droplets present in atmosphere. Size: 0.02µm to 500µm. Particulate pollutants categorized according to size, source and physical state.

14. Particulate Matter particles of different sizes and structures that are released into the atmosphere present in many sources including fossil fuels, dust, smoke, fog, etc. can build up in respiratory system cause heart and lung disease; increases risk of respiratory infection

15. Aerosol Aerosol – a dispersion of solid and liquid particles suspended in gas (air). Aerosol particles larger than about 1 micrometer in size are produced by windblown dust and sea salt from sea spray. After formation, the aerosols are mixed and transported by atmospheric motions. Examples : dust, smoke, mist, fumes.

16. Aerosol

17. Dust: Small solid particles. Size: 1 to 200 µm. Formed by breaking up of larger masses of rock and soil either by disintegration or by mechanical process. Remain suspended in air temporarily but ultimately settle under the influence of gravity.

18. Smoke: Fine solid particles resulting from the incomplete combustion of organic particles like coal, wood, tobacco. Size:0.1 to 1 µm. Fumes: Fine solid particles formed by the condensation of vapour of solid materials. Size: 0.1 to 1 µm. Odourless vapour usually released from chemical as metallurgical process.

19. Mist: Liquid droplets formed by condensation of vapour in the atmosphere or released from industrial operations. Size: smaller than 10 µm. Fog: If the mist is made of water droplets whose concentration is high and dense enough to obscure vision, then mist is called fog.

20. Flyash : Finely divided non combustible particles present in the gases arising from fuel combustion. Contain inorganic metallic or mineral substances released when organic part of coal is burnt. Soot: Incomplete combustion of carbon containing materials release carbon particles.

21. Gas pollutants - SO 2 Properties SO 2 is a colorless gas having pungent and suffocating odour. Reacts with H 2 O and forms sulfurous acid (H 2 SO 3 ), which oxidizes to sulfuric acid (H 2 SO 4 ) Chemical transformation of other pollutants Responsible for acid rain effect

22. Gas pollutants - SO 2 Sources 67% SOx pollution is due to volcanic activities. Remaining 33% SOx emission are due to: Biomass and fossil fuel combustion Industrial emissions( paper manufacturing plants, sulfuric acid plants) Transportation Open burning of refuse and municipal incinerator Controls Low-S fossil fuels (clean coal) Emission control devices

23. Gas pollutants - SO 2 Effects: Irritation of mucous membranes of the respiratory tract. High concentration may cause bronchitis. Marbles and mortar statues are affected. Plants are sensitive to high concentration of SO 2 , result in chlorosis , metabolic inhibition, plasmolysis and even death.

24. Gas pollutants - NO x Properties: NO, NO 2 , N 2 O are primarily involved in air pollution NO is colorless, odourless gas NO 2 is reddish brown gas and having suffocating odour NO and NO 2 are formed as:

25. Gas pollutants - NO x Sources Fuel combustion in automobiles and industries Lightening Forest fire Bacterial decomposition of organic matters

26. Gas pollutants - NO x Effects : Deep lung irritant Nitric oxide can combine with hemoglobin and reduce oxygen carrying capacity of blood. NO is moderately toxic. NO 2 is more toxic, it irritate alveoli of lungs and high concentration may cause acute bronchitis.

27. Effects of air pollution

28. Common effects of air pollutants

29. EFFECTS OF AIR POLLUTION ON HUMAN HEALTH Human Health ACUTE : short duration exposure and/or immediate effects Examples: irritation of eyes, nose and throat upper respiratory infections (bronchitis, pneumonia) headaches nausea allergic reactions, etc.

30. EFFECTS OF AIR POLLUTION ON HUMAN HEALTH Human Health CHRONIC : long duration exposure and/or long term effects Examples: lung cancer heart disease damage to brain, nerves, liver, kidneys, etc.

31. EFFECTS OF AIR POLLUTION ON HUMAN HEALTH Reduced lung functioning Irritation of eyes, nose, mouth and throat Asthma attacks Respiratory symptoms such as coughing and wheezing Increased respiratory disease such as bronchitis Reduced energy levels Headaches and dizziness Neuro -behavioural disorders Cardiovascular problems Cancer

32. Nasal Cavity Nose Mouth Bronchus Bronchiole Alveolus Diaphragm Throat (pharynx) Windpipe (Trachea) Left lungs Ribs

33. Effects of CO: Reacts with hemoglobin in blood –Forms carboxyhemoglobin ( HbCO ) rather than oxyhemoglobin (HbO2) –Prevents oxygen transfer Effect of O3: Cause: atmospheric photochemical reaction Acute Health effects Severe ear/nose/throat irritation Interferes with lung functions Coughing at 2 ppm ozone

34. Effects of SO 2 : Main Effects: Acid Deposition Corrosive Damages lungs Damages structures Damages environment Effects of NO x : Prolonged exposure: pulmonary fibrosis, and higher LRI (lower respiratory tract illness) in children Toxic effects at 10-30 ppm –Nose and eye irritation –Lung tissue damage Pulmonary edema (swelling) Bronchitis

35. Effects of air pollution on plants Have an adverse effect on plants Cause a widespread damage to natural vegetation and economic crops Many species are susceptible to damage even at low concentrations Gaseous pollutants are actively metabolized by some plants and these plants are employed as indicators of air pollutants

36. Effects of air pollution on plants Pollutant Effects on plants SO 2 Bleaching of leaves, necrosis(killing of tissues) NO 2 Suppressed growth, bleaching O 3 Suppressed growth, bleaching, necrosis, collapse of leaf Fluorides Necrosis at leaf tip PAN Suppressed growth, silvering of lower leaf surface Necrotic lesions on lower surface of potato leaves Chlorosis and necrosis of white pine needles Necrosis of watermelon leaf

37. Effects of air pollution on plants Forms of damages to leaves: Necrosis: killing or collapse of tissue Chlorosis: loss or reduction of chlorophyll resulting in fading of the leaf’s green color to yellowish or pale green. Abscission: dropping of leaves Epinasty : downward curvature of leaf due to the higher rate of growth on the upper surface Acute injury: short-time to high concentration occur under fumigation conditions. Effects are noted within few hours to few days- make visible markings on the leaves Chronic injury: long-term to low concentrations

38. Effect of Ozone on plants

39. Effects of air pollution on material/property Damage to property Effects of dry deposition of sulfur dioxide, which causes the formation of gypsum. Gypsum traps particulate matter to form heavy, black incrustation.

40. Effects of air pollution on material/property Effects on Property Many statues, monuments, made from limestone (CaCO 3 ), marble or metal. Acid rain can dissolve rock or tarnish metal

41. Effects of air pollution on material/property Smoke and aerosols adhere to stone, brick and building surface to produce unsightly coatings. SOx in presence of moisture react with limestone and change the color. ( Tajmahal )

42. Effects of air pollution on material/property On paints: Areas high pollution require frequent painting. H 2 S cause darkening of surfaces covered with paint containing white lead. On textiles: SO 2 causes deterioration of natural and synthetic textile fibers. Fading of textile dyes by oxides of nitrogen, ozone.

43. Effects of air pollution on climate/environment When gas pollutants e.g. sulfur dioxide, nitrogen dioxide dissolve in rain water, various acids are formed CO 2 + H 2 O  H 2 CO 3 (carbonic acid) SO 2 + H 2 O  H 2 SO 4 (sulfuric acid) NO 2 + H 2 O  HNO 2 (nitrous acid) + HNO 3 (nitric acid)

44. Acidic Precipitation Fossil fuels Power plants Industrial emissions Auto emissions Primary Pollutants SO 2 NO 2 Secondary Pollutants H 2 SO 4 HNO 3 sulfuric acid nitric acid soils leaching of minerals vegetation direct toxicity indirect health effects sediments leaching aluminum acidic precipitation

46. Global Warming warming of atmosphere due to increases in the concentrations of one or more greenhouse gases primarily as a result of human activities, mainly : burning of fossil fuels In recent decades certain greenhouse gases have increased in concentration: carbon dioxide methane nitrous oxide CFCs CO 2 contributes to ~ 55% of global warming.                                                 

47. Melting of Glacier

48. Ozone Depletion The ozone layer is a layer of gaseous ozone located in the stratosphere The stratosphere contains O 3 “ good ozone ” The ozone layer prevents 99% of harmful ultraviolet radiation from reaching Earth’s surface It is being depleted by CFCs , halons and other chemicals

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