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Air and Air Pollution

The AtmosphereStratosphere11-30 milesLittle water vaporOzone layerUV filterTroposphere11 mile at equator; 8 miles at polesweather breeder78% N, 21% ONatural heatingSolar radiationGreenhouse effect

The AtmosphereExosphereThermosphereionosphereaurorea borialishottest layer1000 CMesospherevery little atmospherecoldest layer

Atmospheric pressure (millibars)02004006008001,0001201101009080706050403020100(SeaLevel)804004080120Pressure = 1,000millibars atground levelTemperature (C)Altitude (kilometers)Altitude (miles)756555453525155ThermosphereHeating via ozoneMesosphereStratosphereOzone layer

Heating from the earthTroposphereTemperaturePressureMesopauseStratopauseTropopause

Altitude (kilometers)Ozone concentration (ppm)Altitude (miles)Stratospheric ozoneStratosphereTroposphere4035302520151050051015200510152025Photochemical ozoneBenefical OzoneHarmful OzoneAir Pollutionintroduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems. the presence of one or more chemicals in the atmosphere in sufficient quantities and duration to (1) cause harm to us, other forms of life, and materials, or (2) alter climate.

Major Classes of Air PollutantsCarbon oxidesCarbon monoxide and carbon dioxideSulfur oxidesSulfur dioxide and sulfur trioxideNitrogen OxidesNitric oxide, nitrogen dioxide, nitrous oxideVolatile Organic CompoundsMethane, propane, CFCs

Photochemical OxidantsOzone, peroxyacal nitrates (PAN), hydrogen peroxide (H2O2)Suspended particulate matter (SPM)Dust, soot, asbestos, lead, nitrate, and sulfate saltsSulfuric acid, PCBs, dioxins, pesticidesRadioactive substancesRadon-222, iodine-131, strontium-90, plutonium-239Hazardous Air Pollutants (HAPS)Criteria Air PollutantsIdentified by the Clean Air Act 1970

EPA uses six "criteria pollutants" as indicators of air qualityNitrogen Dioxide: NO2Ozone: ground level O3Carbon monoxide: COLead: PbParticulate Matter: PM10 (PM 2.5) Sulfur Dioxide: SO2Volatile Organic Compounds: (VOCs)EPA established for each concentrations above which adverse effects on health may occur8Clean Air Act http://www.epa.gov/air/oaq_caa.html Title I - Air Pollution Prevention and ControlPart A - Air Quality and Emission LimitationsPart B - Ozone Protection (replaced by Title VI)Part C - Prevention of Significant Deterioration of Air QualityPart D - Plan Requirements for Nonattainment AreasTitle II - Emission Standards for Moving SourcesPart A - Motor Vehicle Emission and Fuel StandardsPart B - Aircraft Emission StandardsPart C - Clean Fuel VehiclesTitle III - GeneralTitle IV - Acid Deposition ControlTitle V - PermitsTitle VI - Stratospheric Ozone Protection Nitrogen Dioxide (NO2)Properties: reddish brown gas, formed as fuel burnt in car, strong oxidizing agent, forms Nitric acid in airEffects: acid rain, lung and heart problems, decreased visibility (yellow haze), suppresses plant growthSources: fossil fuels combustion, power plants, forest fires, volcanoes, bacteria in soilClass: Nitrogen oxides (NOx) EPA Standard: 0.053 ppmMobile Source Emissions: Nitrogen Oxides

Tropospheric Ozone (O3)Properties: colorless, unpleasant odor, major part of photochemical smogEffects: lung irritant, damages plants, rubber, fabric, eyes, Sources: Created by sunlight acting on NOx and VOC , photocopiers, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion productsClass: photochemical oxidantsOzone (O3)10,000 to 15,000 people in US admitted to hospitals each year due to ozone-related illnessChildren more susceptibleAirways narrowerMore time spent outdoors

Mobile Source Emissions: Hydrocarbons Precursors to Ozone

Carbon Monoxide (CO)Properties: colorless, odorless, heavier than air, 0.0036% of atmosphereEffects: binds tighter to Hb than O2, mental functions and vision, even at low levelsSources: incomplete combustion of fossil fuels 60 - 95% from auto exhaustClass: carbon oxides (CO2, CO)EPA Standard: 9 ppm 5.5 billion tons enter atmosphere/year

Mobile Source Emissions - COLead (Pb)Properties: grayish metalEffects: accumulates in tissue; affects kidneys, liver and nervous system (children most susceptible); mental incapacitation; possible carcinogenSources: particulates, smelters, batteriesClass: toxic or heavy metalsEPA Standard: 1.5 ug/m32 million tons enter atmosphere/yearSuspended Particulate Matter (PM10) Properties: particles suspended in air ( 2NO) high temps(2NO + O2 ---> 2NO2) NO2 (yellowish brown gas)Photochemical Smog

Industrial SmogGray SmogComes from burning coal

Sulfur DioxideSulfuric Acid

ParticulatesUnburned CarbonFig. 17-8 p. 426

Thermal InversionsThermal Inversion- when a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below.The warm inversion layer traps emissions that then accumulate beneath it.

Temperature InversionsSubsidence inversionFig. 17-9 p. 427

Temperature InversionsRadiation inversion

Inversion layerMountainrangeSea breezeDescending warm air massDecreasing temperatureIncreasing altitudeAcid DepositionAcid deposition- occurs when nitrogen oxides and sulfur oxides are released into the atmosphere and combine with atmospheric oxygen and water. These form the secondary pollutants nitric acid and sulfuric acid.Secondary pollutants further break down into nitrate and sulfate which cause the acid in acid deposition. Acid Deposition

Effects of Acid DepositionLowering the pH of lake waterDecreasing species diversity of aquatic organismsMobilizing metals that are found in soils and releasing these into surface watersDamaging statues, monuments, and buildings

Ways to Prevent Air PollutionRemoving sulfur dioxide from coal by fluidized bed combustionCatalytic converters on carsScrubbers on smoke stacksBaghouse filtersElectrostatic precipitators

Stratospheric Ozone The stratospheric ozone layer exists roughly 45-60 kilometers above the Earth.Ozone has the ability to absorb ultraviolet radiation and protect life on Earth.

Formation and Breakdown of OzoneFirst, UV-C radiation breaks the bonds holding together the oxygen molecule )2, leaving two free oxygen atoms: O2 + UV-C -> 2OSometimes the free oxygen atoms result in ozone: O2 + O -> O3Ozone is broken down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B ultraviolet light: O3 + UV-B or UV-C -> O2 + ODepletion of the Ozone LayerGlobal Ozone concentrations had decreased by more than 10%.Depletion was greatest at the polesDecreased stratospheric ozone has increased the amount of UV-B radiation that reaches the surface of Earth. Montreal Protocol- international agreement to reduce CFCs. Indoor Air PollutionSick Building Syndrome

Fig. 17-17p. 43441ChloroformPara-dichlorobenzene:Source: Chlorine-treated water in hot showersSource: Air fresh., moth ballsPossible threat: Cancer Threat: cancer1,1,1-TrichloroethaneSource: Aerosol spraysThreat: Dizziness, irregular breathingNitrogen OxidesSource: Unvented gas stoves and kerosene heaters, woodstovesThreat: irritated lungs, childrens colds, headachesAsbestosSource: Pipe insulation, vinyl ceiling and floor tilesThreat: Lung diseasesCaron Monoxide:Faulty furnaces, unvented gas stoves and kerosene heaters, woodstovesThreat: Headaches, drowsiness, irregular heartbeat, deathMethylene ChlorideSource: Paint strippers and thinnersThreat: Nerve disorders, diabetesRadon-222Source: Radioactive soil and rock surrounding foundation, water supplyThreat: lung cancerStyreneSource: Carpets, plastic products, Threat: kidney and liver damageBenzo-pyreneSource: tobacco smoke, woodstovesThreat: lung cancerFormaldehydeSource: Furniture stuffing, paneling, particle board, foam insulationThreat: irritation of eyes, throat, skin, and lungs, nausea, dizzinessTetrachloroethyleneSource: Dry-cleaning fluid fumes and clothesThreat: nerve disorders, damage to liver and kidneys, possible cancer

Sick Building SyndromeA persistent set of symptoms in > 20% populationCauses(s) not known or recognizableComplaints/Symptoms relieved after exiting building 42Complaints/SymptomsHeadachesFatigueReduced MentationIrritability Eye, nose or throat irritation Dry SkinNasal CongestionDifficulty BreathingNose BleedsNausea43

Building Related IllnessClinically Recognized DiseaseExposure to indoor air pollutantsRecognizable Causes44Clinically Recognized DiseasesPontiac Fever Legionella spp.Legionnaire's DiseaseHypersensitivity PneumonitisHumidifier FeverAsthmaAllergyRespiratory DiseaseChronic Obstructive Pulmonary Disease45Sources of Indoor Air PollutantsBuilding materialsFurnitureFurnishings and fabricsGluesCleaning productsOther consumer productsCombustion appliances (cookers and heaters)Open firesTobacco smokingCookingHouse dust mites, bacteria and mouldsOutdoor air46Important Indoor Air pollutantsNitrogen dioxideCarbon monoxideFormaldehydeVolatile Organic Compounds (VOCs)House dust mites (and other allergens, e.g. from pets)Environmental tobacco smokeFine particlesChlorinated organic compounds (e.g. pesticides) Asbestos and man-made mineral fibres Radon47Most dangerous indoor pollutantsCigarette smokeFormaldehydeRadon-222 gasRadonRadon-222Associated with uranium (U-238) and organic material in rocks2nd leading cause of lung cancer4 picocuriesEPA proposed standard

Fig. 17-18p. 436Effects of Air Pollution on Living Organisms and MaterialsDamage to mucous membranesRespiratory diseases Lung cancerAsthma allergic reactionChronic bronchitis persistent inflammationEmphysema irreversible damage

Nasal cavityOral cavityPharynx (throat)Trachea (windpipe)BronchusRight lungBronchioles(see figure 17.18b)(see figure 17.18c)

Epithelial cellCiliaMucus

BronchioleAlveolar ductAlveoliAlveolar sac(sectioned)Reducing IndoorAir Pollution