Chapter 20 Air Pollution

Transcription

1 Chapter 20 Air Pllutin

2 Overview f Chapter 20 Atmsphere as a Resurce Types and Surces f Air Pllutin Majr Classes f Air Pllutants Surces f Outdr Air Pllutants Urban Air Pllutin Effects f Air Pllutin Cntrlling Air Pllutin in the US

3 Atmspheric Cmpsitin Atmsphere as a Resurce Nitrgen 78.08% Oxygen 20.95% Argn 0.93% Carbn dixide 0.04% Ecsystem services Blcks UV radiatin Mderates the climate Redistributes water in the hydrlgic cycle

4 Types and Surces f Air Pllutin Air Pllutin Chemicals added t the atmsphere by natural events r human activities in high enugh cncentratins t be harmful Tw categries Primary Air Pllutant Harmful substance that is emitted directly int the atmsphere Secndary Air Pllutant Harmful substance frmed in the atmsphere when a primary air pllutant reacts with substances nrmally fund in the atmsphere r with ther air pllutants

5 Majr Air Pllutants-Which d yu think are Primary and Secndary? Primary r Secndary

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7 Majr Classes f Air Pllutants Particulate Material Nitrgen Oxides Sulfur Oxides Carbn Oxides Hydrcarbns Ozne

8 Particulate Material Thusands f different slid r liquid particles suspended in air Includes: sil particles, st, lead, asbests, sea salt, and sulfuric acid drplets Dangerus fr 2 reasns May cntain materials with txic r carcingenic effects Extremely small particles can becme ldged in lungs

9 Nitrgen and Sulfur Oxides Nitrgen Oxides Gases prduced by the chemical interactins between atmspheric nitrgen and xygen at high temperature Prblems Greenhuse gases Cause difficulty breathing Frm acid precipitatin when cmbined with H2O Sulfur Oxides Gases prduced by the chemical interactins between sulfur and xygen Causes acid precipitatin

10 Carbn Oxides and Hydrcarbns Carbn Oxides Gases carbn mnxide (CO) and carbn dixide (CO 2 ) Greenhuse gases CO inhalatin can suffcate persns. Hydrcarbns Diverse grup f rganic cmpunds that cntain nly hydrgen and carbn (ex: CH 4 - methane) Sme are related t phtchemical smg and greenhuse gases

11 Ozne Trpspheric Ozne bad here Man- made pllutant in the lwer atmsphere (frmed by reactin between N x & Hydrcarbns) Secndary air pllutant Cmpnent f phtchemical smg Greenhuse Gas Stratspheric Ozne gd here Essential cmpnent that screens ut UV radiatin in the upper atmsphere Man- made pllutants (ex: CFCs) can destry it

12 Surces f Outdr Air Pllutin Tw main surces Transprtatin Industry Intentinal frest fires is als high, particularly where frests are being cnverted t farmland.

13 Urban Air Pllutin Industrial Smg (smke pllutin) Sulfur xides and particulate matter N lnger a prblem in develped wrld, but is in develping wrld (because their air quality laws and pllutin-cntrl technlgy have nt caught up)

14 Urban Air Pllutin Phtchemical Smg (ex: Ls Angeles belw) Brwnish-range haze frmed by chemical reactins invlving sunlight, nitrgen xide, and hydrcarbns

15 Frmatin f Phtchemical Smg

16 Surces f Smg in Ls Angeles- What are the primary pllutants invlved? NO x NOx Hydrcarbns

17 Case-In-Pint Air Pllutin in Beijing and Mexic City Beijing (left) Mexic City (abve). Visibility 11km 1.6km

18 Effects f Air Pllutin Lw level expsure Irritates eyes Causes inflammatin f respiratry tract Can develp int chrnic respiratry diseases

19 Effects f Air Pllutin

20 Health Effects f Air Pllutin Sulfur Dixide and Particulate material Nitrgen Dixides Causes airway restrictin Carbn mnxide Irritate respiratry tract and impair ability f lungs t exchange gases Binds with irn in bld hemglbin, prevents transfer f CO2 and Oxygen Causes headache, fatigue, drwsiness, death Ozne Causes burning eyes, cughing, and chest discmfrt

21 Children and Air Pllutin Greater health threat t children than adults Air pllutin can restrict lung develpment Children breath mre ften than adults Children wh live in high zne areas are mre likely t develp asthma 1990 autpsies f 100 LA children wh died fr unrelated reasns; 80% had early stage lung disease.

22 Cntrlling Air Pllutin in US Smkestacks with electrstatic precipitatr (right) Withut With Electrstatic precipitatr Electrstatic precipitatr

23 Cntrlling Air Pllutin in the US Smkestacks with scrubbers (right) Particulate material can als be cntrlled by prper excavating techniques

24 Cntrlling Air Pllutin in the US Phase I Vapr Recvery System fr gasline Vaprs frm tank trucked back t plant fr cndensatin r cmbustin. Phase II Vaprs frm aut tank int undergrund strage tank.

25 The Clean Air Act Authrizes EPA t set limits n amunt f specific air pllutants permitted Fcuses n 6 pllutants: lead, particulate matter, sulfur dixide, carbn mnxide, nitrgen xides, and zne Act has led t decreases!

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27 Other Ways t Imprve Air Quality Reduce sulfur cntent in gasline frm its current average f 330 ppm t 30 ppm Require federal emissin standards fr all passenger vehicles Including SUVs, trucks and minivans Require emissin testing fr all vehicles Sulfur clgs catalytic cnverters Including diesel Increase fuel efficiency

28 Ozne Depletin in Stratsphere Ozne Prtects earth frm UV radiatin Part f the electrmagnetic spectrum with wavelengths just shrter than visible light

29 Ozne Depletin in Stratsphere Ozne thinning/hle First identified in 1985 ver Antarctica Caused by human-prduced brmine and chlrine cntaining chemicals Ex: CFCs

30 Ozne Depletin in Stratsphere Hle ver Antarctica requires tw cnditins: Sunlight just returning t plar regin Circumplar vrtex- a mass f cld air that circulates arund the suthern plar regin Islates it frm the warmer air in the rest f the planet Plar stratspheric cluds frm Enables Cl and Br t destry zne (the Cl and Br attach t ice crystals in clud).

31 Effects f Ozne Depletin Higher levels f UVradiatin hitting the earth Eye cataracts Skin cancer (right) Weakened immunity May disrupt ecsystems (Antarctic Phytplanktn) May aid r damage crps and frests

32 Recvery f Ozne Layer Mntreal Prtcl (1987) Reductin f CFCs Started using HFCs (greenhuse gas) & HCFCs (less destructive than CFCs). Phase ut f all zne destrying chemicals is underway glbally Satellite pictures in 2000 indicated that zne layer was recvering Full recvery will nt ccur until 2050

33 Acid Depsitin Sulfur dixide and nitrgen dixide emissins react with water vapr in the atmsphere and frm acids that return t the surface as either dry r wet depsitin ph scale

34 Hw Acid Depsitin Develps

35 Effects f Acid Depsitin Declining Aquatic Animal Ppulatins Thin-shelled eggs prevent bird reprductin Frest decline Because calcium is unavailable in acidic sil Ex: Black frest in Germany (50% is destryed) Sil leaching f Magnisium is als an issue

36 Acid Depsitin and Frest Decline

37 Air Pllutin Arund the Wrld Air quality is deterirating rapidly in develping cuntries Shenyang, China Develping cuntries have lder cars Residents nly see sunlight a few weeks each year Still use leaded gasline 5 wrst cities in wrld Beijing, China; Mexic City, Mexic; Shanghai, China; Tehran, Iran; and Calcutta, India

38 Lng Distance Transprt f Air PllutantsPersistent Cmpunds (DDT & PCB) A single bite f raw whale skin transfers the weekly limit f PCB t Inuit Alaskans.

39 Indr Air Pllutin Pllutants can be 5-100X greater than utdrs Mst cmmn: Radn, cigarette smke, carbn mnxide, nitrgen dixide, frmaldehyde pesticides, lead, cleaning slvents, zne, and asbests

40 Indr Air Pllutin - Radn