Air_Pollution_PM1112233333333333333.pptx

Air pollution

1. Air Pollution and Human Health 1

2. Air pollution Presence of one or more gases or suspended particulate matters in the ambient atmosphere in quantities, of characteristics and of duration so as to be injurious to human, plant or animal life, or which may interfere with the comfortable enjoyment of the life and property is known as air pollution. Air pollution has local, regional and global dimension . Atmospheric pollution has a global magnitude when the frontiers of air pollution are no more confined to any particular part of the earth. 2 Sources of air pollution - Traffic - Power plants - Fossil fuel combustion - Oil refining - Mining - Chemical and pharmaceutical industries - Waste incineration - Agriculture

3. Sources of air pollution 3

4. Types of air pollutants depending on source Point sources : pollutants come from identified area, such as exhaust pipe of an automobile, chimney of a metal industry ……….. Non-point sources : pollutants come from dispersed/ non-identified area, such as chemical blow by the wind … 4

5. Air pollutants depending on form Gaseous : all gases from natural and anthropogenic sources whose concentrations are high in consideration to the space . Example: CO, NO 2 , O 3 , SO 2, Methane, volatile organic compounds (VOCs) 2) Particulate matter (PM ) :finely divided suspended solid particles and/ or liquid droplets in the atmosphere, such as mineral dust , sea-salt, fumes, smoke, fly ash, mist, spray. Size: 0.001 to 10  m in diameter Colloidal size (0.001–1m) particulate matter in the atmosphere is known as aerosol. Example: Particulate matter (PM 10 and PM 2.5 ) Source: Natural and anthropogenic 5

6. Chemically air pollutants fall into the following 2 classes: Inorganic pollutants : such as carbon monoxide, sulfur dioxide, lead 2) Organic pollutants : organic in origin such as gasoline, PCBs ( polychlorinated biphenyls). 6

7. Types of air pollution depending of location: 7

8. Some outdoor air pollutants 8

9. Some important indoor air pollutants 9

10. Types of air pollutants depending on mode of reaction: Primary air pollutants : form primarily from the natural events and human activities, such as SO 2 , CO, NO, NO 2 , SO 2 , particulates, hydrocarbons, metals, ….. (b) Secondary air pollutants : form in the atmosphere when primary pollutants react with one another or with the basic components of air, such as O 3 , other photochemical oxidants e.g., PANs, oxidized hydrocarbons, ….. 10

11. Primary and secondary air pollutants 11

12. Major classes of pollutants 12

13. Process industries and emission of air pollutants (based upon the manufacturing process and the raw materials used) Industry Impurities Cement Process dust, cement, lime, oxides of Al, Si, Ca, Na Fertilizer Dust particles of coal, sulfur, gypsum, NO x , HF, F, CO 2 , SO 2 Paper H 2 S, mercaptan (R-SH), SO 2 , chemical dust, Cl 2 , methyl sulphide Thermal power plants Fly ash, NO x , SO 2 , HC, CO Iron & steel Iron oxide, dust, CO x , cyanides, H 2 S Metallurgical Fumes, dusts, smoke, oxides Heavy chemical industry Acid fumes Sulfuric acid SO 2 Nitric acid NO 2 Petrochemicals & refineries H 2 S, HC, particulates, CO, HCHO, NH 3 , NO 2 , catalyst dusts cyanides, Coal tar Polynuclear hydrocarbons, aerosols of tar Leather and tanneries Mercaptan , sulfides Paints and pigments Nitrobenzene, aniline, thinners and solvents Lead casting and melting Tin, lead fumes, and oxides Sugar H 3 PO 4 , SO 2 13

14. Significant air pollutants in the atmosphere - Carbon monoxide (CO), - Nitrogen dioxide (NO 2 ) - Ozone (O 3 ) - Sulphur dioxide (SO 2 ), - Volatile organic compounds (VOCs)/ hydrocarbons (HC), - PM 2.5 and PM 10 , - Metals 14

15. Chemical species concentration (ppb) in clean and polluted air Parameter Clean air Polluted air Particulate - > 100 µg/m 3 CO 120 1000-10,000 CO 2 320,000 400,000 SO 2 0.2-10 20-200 NO 0.01-0.6 50-750 NO 2 0.1-1 50-250 HNO 2 0.001 1-8 HNO 3 0.02-0.3 3-5 O 3 20-80 100-500 NH 3 1-6 10-25 CH 4 1500 2500 N 2 O 300 - H 2 S 0.2 - Pb 5x10 -3 µg/m 3 0.5-3 µg/m 3 CO 2 is not a pollutant in strait sense, but a heat absorber. 15

16. Half-life H alf life of a chemical species in the atmosphere is defined as the time required for its concentration decrease to half of its initial value. 16

17. Residence time/ lifetime ( ctd .) Residence time (life-time) is defined as the amount of a chemical species in the atmosphere divided by the rate at which the chemical is removed from the atmosphere. Residence/ life time (  ) of a chemical species in the atmosphere is expressed by the following equation,  = M / F where, M = amount of a chemical in the atmosphere F = efflux (i.e., rate of removal plus rate of destruction) of a chemical from the atmosphere If, M and F changes with time (t), the rate of efflux (  t ) will be,  t = M t / F t 17

18. 18 year year year

19. Spatial and temporal scale of variability for some atmospheric chemical species. Temporal scale is presented by residence time. 19

20. Removal/ sink of chemicals Final stage in the life history of a chemical species in the atmosphere is its removal/ sink by chemical or physical processes. Chemical sink or removal process involves the transformation of a chemical species into other chemical species. Physical sink or removal processes: - adsorption onto other atmospheric particles - deposition on earth’s surface - absorption by vegetation Physical removal process is also known as deposition. Deposition is of two types: wet and dry Wet deposition: scavenging of gases and particles by clouds and precipitation. Dry deposition: direct collection of gases and particles by vegetation, earth’s surface and oceans. Dry deposition is much slower than wet deposition. 20

21. Air quality and human health An active person typically inhales about 10,000-20,000 litres of air per day (about 7-40 litres per minute ). This inhalation rate increases with vigorous exercise, such as jogging . During inhalation and exhalation, air pollutants (gases and particulate matters) can inflame, sensitize and even scar the lungs and tissues . Exposure to the air pollution is largely beyond the control of individual both in the developed and developing countries. Air pollutants from the anthropogenic sources may directly affect the well-being of human community and other components of the environmental health . 21

22. Air quality and human health ( ctd .) Air pollution has effects on:- - Human health - Animal health - Vegetation - Natural ecosystem - ozone layer depletion; formation of photochemical smog , industrial smog , acid rain , greenhouse gases etc . So, we need to maintain air quality in order to- - reduce the negative impact of air pollution on human health - protect flora, fauna and materials from air pollution A ir pollution problem can be managed through the action by public authorities at the national, regional and even international level. 22

23. Principal air pollutants affecting human health Some air pollutants are present in sufficient quantities in all ambient air of urban areas, and have potential to threat human health, if they exceed health-based air quality standard. These pollutants are known as criteria pollutants . Criteria air pollutants : - Carbon dioxide (CO), - Nitrogen dioxide (NO 2 ) - Ozone (O 3 ) - Sulphur dioxide (SO 2 ), - PM 2.5 and PM 10 , - Airborne lead Beside these, hundreds of other pollutants may enter in the atmosphere. Concentrations of criteria air pollutants very depending on the level of industrial and traffic activity, and degree of the sophistication control of emission. The standards of criteria pollutants are set to retain a healthy air quality for urban dwellers, flora, fauna and materials of that environment. WHO also recognise the following air pollutants as carcinogens: acrylonitrile, arsenic, benzene, chromium, nickel, polyaerometic hydrocarbons (PAHs) and vinyl chloride . 23

24. Ambient air quality standards, WHO guidelines (µg/m 3 ) vs. Bangladesh Pollutants Average time WHO guidelines 2005 Bangladesh AAQs CO 15 minutes 100,000 - 30 minutes 60,000 - 1 hour 30,000 40,000 8 hour 10,000 10,000 NO 2 1 hour 200 - annual 40 100 O 3 1 hour - 235 8 hour 100-120 157 SO 2 10 minute 500 100 24 hour 20 365 PM 10 24 hour 50 150 annual 20 50 PM 2.5 24 hour 25 65 annual 10 15 Pb Annual 0.5-1.0 0.5 24

25. Properties and pollution significant of criteria pollutants Pollutants Properties Pollution significance Carbon monoxide (CO) Colorless, odorless gas Contributes to greenhouse gas formation, such as CO 2 that has effect on global warming Nitrogen dioxide (NO 2 ) Brown-orange gas Significant component of photochemical smog and acid rain Ozone (O 3 ) reactive gas A secondary air pollutant produced during photochemical smog formation; damages flora and fauna Sulfur dioxide (SO 2 ) Colorless choking gas, soluble in H 2 O to produce H 2 SO 3 Principal components of acid rain; damages humans, flora, fauna and metals PM 10 and PM 2.5 Particulate matter < 10 µm and <2.5 µm in diameter; block smoke Causes reparatory problems Lead ( Pb ) Heavy metal; organic lead compounds are tetra ethyl lead and tetra methyl lead, colorless, less volatile liquid Principal source is leaded petrol, also come from lead pipes, quarrying, incineration; damages humans and fauna when in excess 25

26. Air quality index (AIQ) Air quality index (AQI) is an index number for reporting daily air quality. It tells how clean or polluted the air is in a particular area or region. It focuses on short term human health effects that can happen within few hours or days after breathing. AQI is a scale of number that runs from 0 to 500. The higher the AQI value, greater is the level of air pollution . In Bangladesh, AQI scale is divided into 6 categories, and a specific color is assigned to each AQI category. 26

27. Air quality index (AIQ ) ( ctd .) Air quality index (AQI) for Bangladesh Air quality index (AQI) value Category Color 0 - 50 Good Green 51 - 100 Moderate Yellow green 101 - 150 Caution Yellow 151 - 200 Unhealthy Orange 201 - 300 Very unhealthy Red 301 - 500 Extremely unhealthy Purple 27

28. Human health effects of carbon monoxide (CO ) Carbon monoxide (CO) is produced by the incomplete combustion of carbon based fuels when oxygen content is scarce. It is a systematic poison that affects human health. When CO breathes in, it enters into the blood stream, and then interferes with O 2 absorption by haemoglobin, because the affinity of CO for haemoglobin is 200-240 times higher than O 2 . This reduces O 2 carrying capacity of the blood and therefore, brain and other tissues may starve for oxygen. It exacerbates cardiovascular disease, affects nerves and leads to angina pectoris . Low to moderate concentrations of COHb impair thinking and perception, cause headache, slow reflexes, reduce mental dexterity , decrease exercising capacity and cause drowsiness . At high concentrations of COHb , death can result in . 28

29. Human health effects of o zone ( O 3 ) Ground level ozone (O 3 ) is a constituent of photochemical smog . H ighest level of O 3 pollution generally occurs during sunny weather periods . It is extremely reactive, and at excessive level it has noticeable effect on human health . It can cause breathing problems, trigger asthma, reduce lung function and cause lung disease. 29

30. Human health effects of n itrogen dioxide (NO 2 ) Nitrogen dioxide (NO 2 ) is an oxidizing agent, and it can injure the smallest air passages of the lung . Acute exposure to NO 2 causes respiratory diseases such as cough, sore (inflammation) throat, but together with SO 2 can aggravate bronchitis, asthma and emphysema (a disorder affecting tiny air sacs of the lungs). Symptom of bronchitis in asthmatic children increase with long-term exposure to NO 2 . 30

31. Human health effects of sulphur dioxide (SO 2 ) Sulphur dioxide (SO 2 ) can affect the respiratory system and lung function, and also causes eye irritation. Higher levels of SO 2 can cause inflammation of the respiratory tract, and which then causes coughing, mucus secretion, aggravation of asthma and chronic bronchitis, and makes people more prone to infections of the respiratory tract . Hospital admission of cardiac diseases patient and mortality increases as days with higher SO 2 levels. Synergistic effect can occur when mildly asthmatic patients are exposed to SO 2 along with O 3 . 31

32. Human health effects of particulate matter (PM 10 and PM 2.5 ) Particulate matter (PM) affects more people than any other air pollutants. Health effects of PM occur both in most urban and rural population in both the developed and developing countries . Large inhalable particles, 100-200 µm in diameter, easily trap in the nose and throat, while thoracic particulates, 2.5-10 µm in diameter can reach the upper parts of the lung. Particulate matter smaller than 2.5 µm in diameter can reach tiny air ways during the normal nasal breathing, and even can reach the alveolar region when breathed through the mouth . 32

33. Human health effects of particulate matter (PM 10 and PM 2.5 ) ( ctd .) Chronic exposure to PM can increase risks of developing cardiovascular and respiratory diseases as well as lung cancer . Particulate matter from the indoor combustion of solid fuels or traditional stoves can increase the risks of acute lower respiratory infections and associated mortality among young children . It is also a major risk factor for chronic obstructive pulmonary disease (COPD) and lung cancer among adults . 33

34. Effects of criteria pollutants on human health and environment Criteria pollutants Health effects Environmental effects CO Interferes with oxygen transportation to organs and tissues throughout the body. Thus , it reduces mental alertness, increases heart attack and cardiovascular diseases Contributes to greenhouse gas formation, such as CO 2 that has effect on global warming SO 2 Causes eye irritation, wheezing, chest tightness, shortness of breath, lung damage Contributes to acid rain formation, plant and water damage, aesthetic damage   NO 2 Increases respiratory diseases such as asthma, coughing, wheezing, shortness of breath Contributes to the formation of photochemical smog, acid rain, visibility impairment   O 3 Damages lung tissue, reduces lung function and aggravates asthmatic symptoms Damages plant and ecosystem, has role in global warming   Pb Causes of anemia, high blood pressure, brain and kidney damage, neurological disorders, cancer, lowered IQ   Affects animals and plants , aquatic ecosystems PM Accumulates in the respiratory system; increases asthma, bronchitis and lung damage; and also increases cardiovascular disease which leads to unexpected mortality Causes visibility impairment, atmospheric deposition, aesthetic damage 34