AIR-POLLUTION空氣污染課件(PPT 50頁)

1、AIR POLLUTION第1頁，共50頁。OUTLINEThe atmosphereCategories of Air PollutantsControl of Air PollutantsAcid depositionGlobal Warming and Climate ChangeOzone depletionIndoor air pollutant第2頁，共50頁。ATMOSPHERETroposphere 對(duì)流層Stratosphere 平流層Ionosphere 電離層第3頁，共50頁。Troposphere Where the weather is!Location - 17 k

2、m at the equator, and about 8 km over the poles. Composition N2 78% O2 21% . Water vapor accounts for 0.01% to 5%.第4頁，共50頁。Stratosphere Location - 17- 48km. Very thin air - virtually no weather, and no turbulence.Composition- Similar to troposphere, water vapor is 1000 x less, ozone is 1000 x greate

3、r.第5頁，共50頁。OUTDOOR AIR POLLUTIONPrimary air pollutant released in their unmodified forms and in sufficient quantities to pose a health risk.Carbon monoxide, hydrocarbon, dust or smoke particles, sulfur dioxide, and nitrogen compounds. P389, table 17.1第6頁，共50頁。Categories of Air PollutantsPrimary Air

4、PollutantsFive major materials released directly into the atmosphere in unmodified forms.Secondary air pollutants form under reaction of primary pollutants and water or sunlight.Criteria Air Pollutants are those pollutants for which specific air quality standards have been set.第7頁，共50頁。Primary Air P

5、ollutantsCarbon Monoxide - Produced when organic materials are incompletely burned.Single largest source is the automobile.Not a persistent pollutant.Makes hemoglobin less able to carry oxygen.Most dangerous in enclosed spaces第8頁，共50頁。Volatile Organic CompoundsHydrocarbonsEvaporated from automobile

6、fuel or remnants of fuel incompletely burned.Catalytic converters used to burn exhaust gases more completely.第9頁，共50頁。Particulate Matter - Minute pieces of solid materials ( 10 microns) dispersed into the atmosphere.PM10 and PM 2.5Larger than 2.5 microns are primary pollutants; Smaller than 2.5 are

7、mostly secondary pollutants.Can accumulate in lungs and interfere with the ability of lungs to exchange gases.第10頁，共50頁。Sulfur Dioxide (SO2) - produced when sulfur-containing fossil fuels are burned.Today over 65% of SO2 released into the atmosphere is primarily from coal-burning power plants.Oxides

8、 of Nitrogen (NOx) - Formed when combustion takes place in the air.N and O molecules from the air may react with one another.NO, NO2Automobile engine is primary source.第11頁，共50頁。Lead (Pb) can enter the body through breathing airborne particles or consuming lead deposited on surfaces.Leaded gasoline

9、was primary source.Currently, about 80% of gasoline sold in the world is unleaded.Lead第12頁，共50頁。Lead Emissions第13頁，共50頁。Photochemical SmogA mixture of primary and secondary pollutants. Forms when primary pollutants interact under the influence of sunlight.Two most destructive components:OzonePeroxya

10、cetyl Nitrates (PAN) 過氧乙酰硝酸酯Permanent Lung DamageDamages PlantsDestroys Chlorophyll第14頁，共50頁。第15頁，共50頁。Formation: P. 393第16頁，共50頁。Which contribute to smogInternal combustion engine- automobileIndustrial - Caused by burning coal and oil. Now mainly a problem in countries with infant industrial progra

11、ms.Thermal Inversions第17頁，共50頁。第18頁，共50頁。第19頁，共50頁。Other air pollutantsRadonToxic chemicals leaks or manufacturing process第20頁，共50頁。Acid DepositionSulfur Dioxide and Nitrogen oxides are carried aloft by wind and form secondary pollutants (acids), and then are carried back to earth in wet (snow, rain

12、, fog) and dry (particulate) form. 第21頁，共50頁。Acid rain - what is it?rain is naturally slightly acidic because of the CO2 dissolved in it, a pH of above 5.0. in some parts of the world it can be as low as 4.0 ,where the SO2 and H2S form H2SO4 in the rain, e.g. Naturally near volcanoesAfter the Indust

13、rial Revolution, some regionso the term acid rain is now used to describe rain with a pH below 5.第22頁，共50頁。Acid Rain - Where does it come from?About 70% of acid rain comes from sulfur dioxide (SO2), which dissolves into the water to form sulfuric acid (H2SO4).The rest comes from various oxides of ni

14、trogen -mainly NO2 (nitrite) and NO3 (nitrate) collectively called NOx.These gases are produced almost entirely from burning fossil fuels, mainly in power stations and road transport第23頁，共50頁。UK第24頁，共50頁。第25頁，共50頁。Acid Deposition - Harmful EffectsProperty/ Structural DamageFoliage DamageWeakened Pla

15、nt DefensesAquatic life damage第26頁，共50頁。EFFECTS OF AIR POLLUTION ON LIVING ORGANISMS AND MATERIALSDamage to Human HealthProlonged Exposure - Prolonged exposure can lead to breakdown of natural defenses, leading to lung cancer, asthma, chronic bronchitis, and emphysema.第27頁，共50頁。Damage to PlantsChron

16、ic Exposure - Breaks down cuticle, thus leaving plants less able to adapt to sudden changes in env. conditions.Productivity - Overall productivity of European forests has been reduced by 16%, mostly because of air pollution.第28頁，共50頁。第29頁，共50頁。Damage to Aquatic Lifelakes and rivers become acidic fis

17、h die, lots of fish die due to short term increases in acid levels - Acid Shock - Caused by sudden runoff of large amounts of highly acidic water, either following heavy snowmelt, or when heavy rains follow a prolonged draught.第30頁，共50頁。 greatest threat is from long-term increases, which stop the fi

18、sh reproducing extra acid - frees toxic metals previously held in rocks, especially aluminium, which prevents fish from breathing single-celled plants and algae in lakes decline if the pH virtually everything is dead第31頁，共50頁。第32頁，共50頁。Property/ Structural DamageSulfuric acid reacts with limestone t

19、o form water soluble gypsum.第33頁，共50頁。Slowing acid rain Reduce the amount of SO2 and NOx being released to the atmosphere SO2 emissions from power stations can be reduced byusing a fuel with a low S content low S content fuels - expensive due to demandhigh S content fuels - treated to reduce S conte

20、nt - very expensive. absorb SO2 during combustion, less effective, 8 cents per kWh in china at least.第34頁，共50頁。Catalytic converter to cars to reduce the emissions of NOx by up to 90% (but expensive and releases more CO2)OR dont burn fossil fuels - use alternative energy sources, AND conserve energy第

21、35頁，共50頁。Ozone DepletionOverviewOzone is formed in the stratosphere when high- energy ultraviolet radiation splits diatomic oxygen into atomic oxygen. The atomic oxygen may then combine with another diatomic oxygen molecule to form tri-atomic oxygen (Ozone).第36頁，共50頁。Problem:In 1974, it was discover

22、ed that CFCs were lowering the average concentration of ozone in the stratosphere.CFCs take 10-20 years to make it into the stratosphere. Ozone depletion to next century.第37頁，共50頁。PropertiesDeveloped in 1930sChemically stableOdorlessNon-flammableNon-corrosiveCheapCFCsUsesAppliance coolantsSpray prop

23、ellantsStyrofoam building blocks第38頁，共50頁。In the stratosphere, UV radiation breaks down CFC molecules, releasing atomic chlorine. A free Chlorine atom reacts with an ozone molecule, converting it from O3 to O2. Cl + O3 = ClO + O2Cl + O Cl + O3 = ClO + O2Unstable第39頁，共50頁。Consequences of Ozone LossMo

24、re UV radiation will reach Earths surface.More/Worse sunburns - leading to increased rates of skin cancersSuppression of immune systemLower crop yields第40頁，共50頁。GLOBAL WARMINGIPCC conclusionsAvg. T increased .3-.6C, sea level 10-25cmStrong correlation between increase in T and greenhouse gasesHuman

25、activity increase amount of greenhouse gasesWhat cause global warming?第41頁，共50頁。Changes in Average Global Temperature第42頁，共50頁。Possible Effects of A Warmer WorldWider Temperature Extremes, health effectsRising Sea Level Changes in forestsBiodiversity reductionChanges in food production, etc.第43頁，共50

26、頁。Sea Level Rise warming may be greatest at the poles with melting of the ice caps and sea level rise massive changes in global rainfall patterns Pacific Islands AND reefs drowned, loss of important marine biodiversity, only 4 m above sea level estuarine shores retreat with rising sea level in absen

27、ce of human development第44頁，共50頁。GREENHOUSE GASESCarbon Dioxide - fossil fuel burning, land clearing/burning.Chlorofluorocarbons - refrigerants.Methane - Breakdown of organic material by anaerobic bacteria.Nitrous Oxide - Biomass burning, breakdown of nitrogen-rich products.第45頁，共50頁。第46頁，共50頁。 concentration of CO2 increasing since industrial revolution combustion of fossil fuels and wood 14% increase since 1958 (accurate records) by 2075, concentrations predicted to have doubled since