Air Pollution. Environmental Science Mr. Moss RHS

Transcription

1 Air Pllutin Envirnmental Science Mr. Mss RHS

2 RHS Envirnmental Science 2

3 RHS Envirnmental Science 3

4 Definitin Air Pllutin is the presence f chemicals in the trpsphere in cncentratins high enugh t harm rganisms, ecsystems, r materials, and high enugh t alter climate. Can range frm annying t lethal. RHS Envirnmental Science 4

5 Surces Cme frm bth natural and human surces. Natural surces: Dust (windstrms) Wildfires Vlcanic eruptins Vlatile Organic Chemicals (VOC s) Released frm sme plants Human surces: Mst are in industrialized and urban areas. High cncentratin f peple, factries, and cars. Mst cme frm the burning f fssil fuels in Pwer plants and factries (statinary surces) Mtr vehicles (mbile surces). RHS Envirnmental Science 5

6 Refining the Definitin Pllutin is smething prduced by humans that interferes with ur well-being. Althugh natural surce fit ur definitin, they are generally nt cntrlled by humans. We will fcus n thse factrs that are cntrlled by humans. RHS Envirnmental Science 6

7 Outdr Pllutants Tw main categries; Primary Pllutants Emitted directly int the air. Secndary Pllutants Primary pllutants that react with cmpnents f air t frm new harmful pllutants. RHS Envirnmental Science 7

8 Primary Pllutants CO CO 2 SO 2 NO NO 2 Mst hydrcarbns Mst suspended particles Surces Natural Statinary Secndary Pllutants SO 3 HNO 3 H 3 SO 4 H 2 O 2 O 3 PANs Mst NO 3 and SO 2 4 salts Mbil e Fig. 19-3, p. 442

9 Surces f Primary Pllutants Pllutant Carbn Mnxide Hydrcarbns Particulates Sulfur Dixide Surces Incmplete burning f fssil fuels Tbacc smke Incmplete burning f fssil fuels Tbacc smke Chemicals Burning fssil fuels Farming peratins Cnstructin peratins Industrial wastes Building demlitin Burning fssil fuels Smelting re Nitrgen Cmpunds Burning fssil fuels 9

10 Questin Hw des yur daily lifestyle prduce sme f each f the primary air pllutants shwn in the previus slide? RHS Envirnmental Science 10

11 News Gd Over the past 30 years, utdr air quality in mst develped cuntries has imprved. Passage f air pllutin laws. Bad WHO estimates 1 ut f 6 peple n the earth (1.1 billin) lives in urban areas. Pr air quality Mst live in develping cuntries. Majr threat is frm indr air pllutin. Heating and cking RHS Envirnmental Science 11

12 The Relatinship The prblem f air pllutin is directly related t the size f the ppulatin living in an area and their activities. If ppulatin is small and energy use is lw, impact is small. Pllutin is diluted and negative effect is slight. In urbanized, industrialized civilizatins where use f fssil fuels is high, we release large amunts f pllutin int the envirnment. RHS Envirnmental Science 12

13 Relatinship The released particles are mixed and diluted but stay near the earth due t gravity. We dn t get rid f it. We just dilute it and mve it ut f the immediate area. In urbanized, industrialized areas, these particles d nt have time t dilute befre reaching anther city. This magnifies and adds t the prblem. RHS Envirnmental Science 13

14 As an air mass mves acrss frm west t east, each ppulatin adds t the ttal lad in the atmsphere. RHS Envirnmental Science 14

15 Health Risks Pllutin is nt nly ugly t lk at, it pses a health risk. Especially t: Respiratry illness patients The elderly The very yung Brnchial inflammatin Allergic Reactins Irritatins f mucus membranes RHS Envirnmental Science 15

16 Dnra City in Pennsylvania Octber 1948 Pllutin frm a zinc plant and steel mills became trapped in a valley frming a dense smg. Within 5 days, 17 peple died 5,910 persns became ill Affected almst 50% f the city s 12,300 ppulatin. RHS Envirnmental Science 16

17 Megacities What d Beijing, Seul, Mexic City, and Cair have in cmmn? All are megacities in a develping wrld that have extremely pr air quality. Each als exceed the W.H.O. guidelines fr air quality fr at least tw pllutants. Air quality in Mexic City cntributes t apprximately 6,400 deaths each year. Death rates increase and general health f ppulatin is lwered. RHS Envirnmental Science 17

18 Majr Air Pllutants These include: Carbn Oxides Nitrgen Oxides Sulfur Oxides Suspended Particulate Matter Vlatile Organic Cmpunds Ozne RHS Envirnmental Science 18

19 Carbn Oxides The tw main xides f carbn that we will fcus n are: Carbn mnxide Carbn dixide RHS Envirnmental Science 19

20 Carbn mnxide (CO) Odrless, clrless, highly txic gas. Frms frm incmplete cmbustin f carbncntaining materials. 2C + O 2 2CO Majr surces Mtr Vehicle Exhaust Tbacc smke Clearing and burning f frests/grasslands Open fire cking and inefficient stves RHS Envirnmental Science 20

21 Health Risks f CO Reacts with hemglbin in red bld cells. A prtein in RBC that carries xygen. Reduces ability f bld t transprt xygen. Chrnic expsure can trigger Heart attacks Aggravate lung diseases Asthma Brnchitis Emphysema High levels cause headaches, nausea, drwsiness, mental impairment, cllapse, cma, and death. Several hurs f expsure t 0.001% cncentratin can cause death. RHS Envirnmental Science 21

22 Whatchathinkbutit? The tw majr surces are mtr vehicle exhaust and tbacc smke. Knwing the health implicatins, put yurself n any f the interstates arund Atlanta, GA, n a warm day, between the hurs f 4:00 p.m. and 6:00 p.m.. Discuss with yur grup any ptential prblems with driver alertness. List yur answers n paper and be prepared t share with the class. 5 Minutes t discuss RHS Envirnmental Science 22

23 Effects f CO n Driver The amunt f CO prduced in heavy traffic can cause headaches, drwsiness, and blurred visin. A heavy smker in traffic is dubly expsed and may experience severely impaired reactin time cmpared t nnsmking drivers. RHS Envirnmental Science 23

24 Gd News CO is nt a persistent pllutant. Natural prcesses cnvert CO t ther nn-harmful cmpunds. RHS Envirnmental Science 24

25 Carbn dixide (CO 2 ) A clrless, drless gas. Abut 93% f CO 2 in the trpsphere is the result f the natural carbn cycle. Remaining 7% results frm human activities. Burning fssil fuels Clearing frests/grasslands Nt regulated by the U.S. Clean Air Act Deep-pcket lbbyist. RHS Envirnmental Science 25

26 Nitrgen Oxides Nitrgen Oxide (NO) is a clrless gas. Reactin f Nitrgen and Oxygen in high-temp cmbustin. N 2 + O 2 2NO Nitrgen dixide (NO 2 ) reacts with water in the atmsphere t frm: Nitric acid (HNO 3 ) Nitrate salts (NO 3- ) Plays a rle in the frmatin f phtchemical smg. Nitrus xide (N 2 O) is a greenhuse gas emitted frm fertilizers, animal wastes, and burning fssil fuels RHS Envirnmental Science 26

27 Sulfur Oxides Sulfur dixide (SO 2 ) is a clrless gas with a bad dr. 1/3 f the amunt in trpsphere cmes frm natural surces. 2/3 s cme frm human surces. Use f cal t prduce electricity, il refining, smelting Can react with water vapr t frm sulfuric acid (H 2 SO 4 ) and sulfate salts (SO 4 2- ). These can lead t acid depsitin. Aggravate respiratry prblems, crrde metals, damage paint, paper, leather, and stne. RHS Envirnmental Science 27

28 SPM Suspended Particulate Matter slid particles and liquid drplets small and light enugh t stay suspended in the air fr shrt t lng perids f time. 62% cmes frm natural surces. Dust, Wildfires, sea salt nuclei 38% frm human surces Plwing fields, rad cnstructin, unpaved rads, tbacc smke, calburning industrial plants, mtr vehicles Fine SPM (PM-10) is 10 micrns Ultrafine SPM (PM-2.5) is 2.5 micrns Results in apprximately 60,000 premature deaths per year in the U.S. RHS Envirnmental Science 28

29 Ozne O 3 O 2 + UV light + O O 3 Clrless and highly reactive gas Gd in stratsphere but bad in trpsphere Majr cmpnent f phtchemical smg. Can cause and aggravate respiratry prblems. RHS Envirnmental Science 29

30 VOCs Vlatile Organic Cmpunds- rganic cmpunds that exist as gases in the air. Mstly hydrcarbns such as isprene (C 3 H 8 ) and terpenes (C 10 H 15 ) that are emitted by plant leaves, and methane (CH 4 ). 1/3 f methane emissin are natural (plants, wetlands, and termites) 2/3 s f methane is frm human surces (rice paddies, landfills, il and gas wells, cw farts) Others include benzene, vinyl chlride, and trichlrethylene. RHS Envirnmental Science 30

31 Radn (Rn) #86 n Peridic Table; ne f the Nbel Gases Radiactive gas fund in sme types f rck and sils. Seeps int hmes and buildings that are situated abve the surce. Has been linked t lung cancer. RHS Envirnmental Science 31

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34 Phtchemical Smg A chemical reactin that is activated by light. A mixture f primary and secndary pllutant in the presence f UV radiatin VOC s + N x + heat + UV phtchemical smg Mixture f Ozne, nitric acid, aldehydes, perxyacl nitrates and ther secndary pllutants Htter days lead t increased levels f zne and ther cmpnents. As traffic increases, smg increases. RHS Envirnmental Science 34

35 5 Factrs Reducing Air Pllutin Heavier particles settle ut due t gravity. Precipitatin helps t clean the air f pllutants Salty sea spray can wash ut PM and sluble pllutants Winds carry pllutants away and help dilute by mixing actins Chemical reactins in the atmsphere RHS Envirnmental Science 35

36 6 Factrs Increasing Air Pllutin Buildings can reduce wind speed causing less dilutin Surrunding hills and muntains can reduce air flw t valleys Higher temperatures prmte chemical reactins t frm phtchemical smg VOC emissins frm certain trees and plants (sme aks, sweet gums, pplars, and kudzu) Grasshpper effect- pllutants are transprted frm trpics tward ples. Temperature inversins RHS Envirnmental Science 36

37 Acid Depsitin a.k.a. Acid Rain Industrial smkestacks can input SO x and NO x abve the inversin Reduces lcal but increases reginal pllutin These pllutants may travel ver 600 miles (1000 m) Alng the way, they frm secndary pllutants frm the chemical reactins with the water vapr Descend in tw frms Wet depsitin ph less than 5.6 rain, snw, fg, clud vapr 4 14 days Dry depstin acidic particles 2-3 days RHS Envirnmental Science 37

38 Acid Depsitin Reginal issue frm cal-fired plants and areas with many cars. Eastern U.S. precipitatin is abut ph x greater than nrmal rain which has a ph f 5.6 Muntains in Eastern U.S. and thse east f Ls Angeles have fg and dew with a ph f 2.3 this is mre acidic than lemn juice 1000 times greater than nrmal rain RHS Envirnmental Science 38

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41 Acid Depsitin In sil, sme cmpunds such as limestne (CaCO 3 ) can react with the acid t help neutralize it. This is knwn as Buffering On muntains, there is a thin sil layer s the buffering is minimal Sme areas have received s much depsitin that the sil is unable t buffer the acids. RHS Envirnmental Science 41

42 Effects f Acid Depsitin Cntributes t respiratry illnesses Leaching f txic metals int water supplies Bimagnificatin f Hg Building and Mnument damage Car finishes Increase f acidity in aquatic ecsystems Farms and crpland RHS Envirnmental Science 42

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