3Atmospheric pressure (millibars) Altitude (kilometers) 2004006008001,00012075Highlights:Pressure decreases with altitude until it reaches zeroTroposphere is the layer we live in; mostly N and O; weather; colder as you go upStratosphere: has the ozone layer; warmer as you go upEnvironmental science focuses mostly on those two layersTemperature110Pressure65100Thermosphere905580Heating via ozoneMesosphere4570Altitude (kilometers)60Altitude (miles)3550Stratosphere40253015Ozone “layer”20Heating from the earthTroposphere105Pressure = 1,000millibars atground level(SeaLevel)–80–404080120Temperature (˚C)
4What SPF is that ozone?Stratospheric ozone absorbs 95% of UV radiation3O UV 2 O3Tropospheric ozone is harmful to plants, animals, and humans.Tropospheric ozone is made when air pollutants undergo chemical reactions because of UV exposure.
5Which ozone is which?The oxygen atom generated from the initial reaction reacts with atmospheric, diatomic oxygen, to form ozone.This polluting ozone of the lithosphere, traps heat and contributes to thermal inversion.
8Primary vs. Secondary Primary Pollutants CO CO2 Secondary Pollutants SO2NONO2SO3Most hydrocarbonsHNO3H2SO4Most suspendedparticlesH2O2O3PANsSO42–MostNO3–andsaltsSourcesNaturalStationaryMobilePrimary vs. Secondary
9Tip – Can’t remember what organic compounds are??? View my PS (Chapter 9) PPT online for a quick refresher.
10Table 20-1 Page 436 Major classes of air pollutants Class Carbon oxidesSulfur oxidesNitrogen oxidesVolatile organic compounds (VOCs)Suspended particulate matter (SPM)Photochemical oxidantsRadioactive substancesHazardous air pollutants (HAPs), which cause health effects such as cancer, birth defects, and nervous system problemsExamplesCarbon monoxide (CO) and carbon dioxide (CO2)Sulfur dioxide (SO2) and sulfur trioxide (SO3)Nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (N2O) (NO and NO2 often are lumped together and labeled NOx)Methane (CH4), propane (C3H8), chlorofluorocarbons (CFCs)Solid particles (dust, soot, asbestos, lead, nitrate, and sulfate salts), liquid droplets (sulfuric acid, PCBs, dioxins, and pesticides)Ozone (O3), peroxyacyl nitrates (PANs), hydrogen peroxide(H2O2), aldehydesRadon-222, iodine-131, strontium-90, plutonium-239 (Table 3-1, p. 49)Carbon tetrachloride (CCl4), methyl chloride (CH3Cl), chloroform (CHCl3), benzene (C6H6), ethylene dibromide (C2H2Br2), formaldehyde (CH2O2)Table 20-1 Page 436
11Carbon Monoxide CARBON MONOXIDE (CO) Table 20-2 Major Outdoor Air PollutantsCARBON MONOXIDE (CO)Description: Colorless, odorless gas that is poisonous to air-breathing animals; forms during the incomplete combustion of carbon-containing fuels (2 C + O2 2 CO).Major human sources: Cigarette smoking (p. 409), incompleteburning of fossil fuels. About 77% (95% in cities)comes from motor vehicle exhaust.Health effects: Reacts with hemoglobin in red blood cells and reduces the ability of blood to bring oxygen to body cells and tissues. This impairs perception and thinking; slows reflexes; causes headaches, drowsiness, dizziness, and nausea; can trigger heart attacks and angina; damages the development of fetuses and young children; and aggravates chronic bronchitis, emphysema, and anemia. At high levels it causes collapse, coma, irreversible brain cell damage, and death.Carbon Monoxide
12Table 20-2 Page 438 Nitrogen Dioxide NITROGEN DIOXIDE (NO2) Table 20-2 Major Outdoor Air PollutantsTable 20-2 Page 438NITROGEN DIOXIDE (NO2)Description: Reddish-brown irritating gas that gives photochemical smog its brownish color; in the atmosphere can be converted to nitric acid (HNO3), a major component of acid deposition.Major human sources: Fossil fuel burning in motor vehicles (49%) and power and industrial plants (49%).Health effects: Lung irritation and damage; aggravates asthma and chronic bronchitis; increases susceptibility to respiratory infections such as theflu and common colds (especially in young children and older adults).Environmental effects: Reduces visibility; acid deposition of HNO3 can damage trees, soils, and aquatic life in lakes.Property damage: HNO3 can corrode metals and eat away stone on buildings, statues, and monuments; NO2 can damage fabrics.Nitrogen Dioxide
13Table 20-2 Page 438 Sulfur Dioxide SULFUR DIOXIDE (SO2) Table 20-2 Major Outdoor Air PollutantsTable 20-2 Page 438SULFUR DIOXIDE (SO2)Description: Colorless, irritating; forms mostly from the combustion of sulfur containing fossil fuels such as coal and oil (S + O2 SO2); in the atmospherecan be converted to sulfuric acid (H2SO4), a major component of acid deposition.Major human sources: Coal burning in power plants (88%) and industrial processes(10%).Health effects: Breathing problems for healthy people; restriction of airways in people with asthma; chronic exposure can cause a permanent condition similar to bronchitis. According to the WHO, at least 625 million people are exposed to unsafe levels of sulfur dioxide from fossil fuel burning.Environmental effects: Reduces visibility; acid deposition of H2SO4 can damage trees, soils, and aquatic life in lakes.Property damage: SO2 and H2SO4 can corrode metals and eat away stone on buildings, statues, and monuments; SO2 can damage paint, paper, and leather.Sulfur Dioxide
14Suspended Particulate Matter Table 20-2 Major Outdoor Air PollutantsTable 20-2 Page 438SUSPENDED PARTICULATE MATTER (SPM)Description: Variety of particles and droplets (aerosols) small and light enough to remain suspended in atmosphere for short periods (large particles) to long periods(small particles; Figure 20-6, p. 441); cause smoke, dust, and haze.Major human sources: Burning coal in power and industrial plants (40%), burning diesel and other fuels in vehicles (17%), agriculture (plowing, burning off fields), unpaved roads, construction.Health effects: Nose and throat irritation, lung damage, and bronchitis; aggravates bronchitis and asthma; shortens life; toxic particulates (such as lead, cadmium, PCBs, and dioxins) can cause mutations, reproductive problems, cancer.Environmental effects: Reduces visibility; acid deposition of H2SO4 droplets candamage trees, soils, and aquatic life in lakes.Property damage: Corrodes metal; soils and discolors buildings, clothes, fabrics, and paints.Suspended Particulate Matter
15Table 20-2 Major Outdoor Air Pollutants Table 20-2 Page 438LEADDescription: Solid toxic metal and its compounds, emitted into the atmosphere as particulate matter.Major human sources: Paint (old houses), smelters (metal refineries), lead manufacture, storage batteries, leaded gasoline (being phased out in developed countries).Health effects: Accumulates in the body; brain and other nervous system damage and mental retardation (especially in children); digestive and other health problems; some lead-containing chemicals cause cancer in test animals.Environmental effects: Can harm wildlife.Lead
16Table 20-2 Page 438 Ozone OZONE (O3) Table 20-2 Major Outdoor Air PollutantsTable 20-2 Page 438OZONE (O3)Description: Highly reactive, irritating gas with an unpleasant odor that forms in the troposphere as a major component of photochemical smog (Figures 20-3 and 20-5).Major human sources: Chemical reaction with volatile organic compounds (VOCs, emitted mostly by cars and industries) and nitrogen oxides to form photochemical smog (Figure 20-5).Health effects: Breathing problems; coughing; eye, nose, and throat irritation; aggravates chronic diseases such as asthma, bronchitis, emphysema, and heart disease; reduces resistance to colds and pneumonia; may speed up lung tissue aging.Environmental effects: Ozone can damage plants and trees; smog can reduce visibility.Property damage: Damages rubber, fabrics, and paints.Ozone
18SmogPhotochemical: “brown air smog” Caused by UV reacting with chemicals (NOx, VOCs in the atmosphere) Found in modern cities, especially in warm, sunny areas.Industrial smog: “gray air smog” Caused by burning of fossil fuels, adds sulfur to air. Rare in developed countries now as soot is removed by filters..
19Photochemical SmogNitrogen oxide is an essential ingredient of photochemical smog that is produced during the high temperatures associated with combustion of vehicle’s engines.Be sure to look at sheet “Chemistry is indeed relevant to APES.”
20Initial reaction of nitrogen dioxide with sunlight
21Factors in smog formation Decrease smogIncrease smogUrban buildingsHills and mountainsHigh temperatures“Grasshopper Effect”PrecipitationSalty sea sprayWindReduce factory/car emissions
22“Grasshopper Effect”This is one reason why the dangerous chemicals Canada banned more than 20 years ago continue to turn up in the Great Lakes.
23View “Chemistry is indeed relevant to APES.” See equation – reactants and products of photochemical smog on sheet.Hydrocarbons (including VOC’s), carbon monoxide, and nitrogen oxides from vehicle exhausts are irradiated by sunlight in the presence of oxygen gas.The resulting reactions produce a potentially dangerous mixture that include other NOx, ozone, and irritating organic compounds (VOC’s), as well as CO2 and H2O vapor
27Chemistry and Acid Rain The pH of rainwater is normally slightly acidic, at about 5.6, due mainly to reaction of carbon dioxide with water to form carbonic acid.Refer to “Chemistry is indeed relevant to APES.”
28Gases from natural events Volcanic eruptions, forest fires, and lightning produce sulfur dioxide, sulfur trioxide, and nitrogen dioxide.These gases can react with atmospheric water in much the same way that carbon dioxide does to produce sulfurous acid, sulfuric acid, nitric acid and nitrous acid.Refer to “Chemistry is indeed relevant to APES.”
29Acid Rain formation Wind Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3)Windborne ammonia gasand particles of cultivated soilpartially neutralize acids andform dry sulfate and nitrate saltsWet acid deposition(droplets of H2SO4 andHNO3 dissolved in rainand snow)Nitric oxide (NO)Dry aciddeposition(sulfur dioxidegas and particlesof sulfate andnitrate salts)Sulfur dioxide (SO2)and NOAcid fogFarmLakes in shallowsoil low inlimestonebecomeacidicOceanLakes indeep soilhigh in limestoneare bufferedAcid Rain formation
30Which location does sulfuric & nitric acids transform? WindXZYFarmOceanWhich location does sulfuric & nitric acids transform?
31Identify the type of acid deposition at point Y WindTransformation tosulfuric acid (H2SO4)and nitric acid (HNO3)ZYFarmOceanIdentify the type of acid deposition at point Y
32Identify the type of acid deposition at point Z WindXZDry aciddepositionFarmOceanIdentify the type of acid deposition at point Z
34Which chemicals lower the pH of rain? Primary PollutantsCOCO2Secondary PollutantsSO2NONO2SO3Most hydrocarbonsHNO3H2SO4Most suspendedparticlesH2O2O3PANsSO42–MostNO3–andsaltsSourcesNaturalStationaryMobileWhich chemicals lower the pH of rain?
35Secondary Pollutants in RED Primary PollutantsCOCO2Secondary PollutantsSO2NONO2SO3Most hydrocarbonsHNO3H2SO4Most suspendedparticlesH2O2O3PANsSO42–MostNO3–andsaltsSourcesNaturalStationaryMobileSecondary Pollutants in RED
37Effects of Acid Rain Decrease soil pH (more acidic) Decrease pH of rivers, lakes, ponds, etcFish killsLung/respiratory problemsDegrade metal pipes, leading to water pollutionPlants become susceptible to disease, parasites, etc
38Acid Rain Prevention and Solution SolutionsAcid DepositionPreventionCleanupReduce air pollution by improving energy efficiencyAdd lime to neutralizeacidified lakesReduce coal useAdd phosphatefertilizer to neutralizeacidified lakesIncrease natural gas useIncrease use ofrenewable resourcesAcid Rain Prevention and SolutionBurn low-sulfur coalRemove SO2 particulates, and Nox from smokestack gasesRemove Nox from motor vehicular exhaustTax emissions of SO2
40Go outside and play Indoor air is typically a greater threat People are inside up to 98% of their timeLess air flow to remove pollutantsTop pollutants: cigarette smoke, formaldehyde, radon, particulate matter.“Sick building” Typically newer buildings because of less air leaks. Symptoms: headache, coughing, sneezing, tiredness.
41FormaldehydeFound in: plywood, furniture, upholstery, floor adhesives, dry cleaning chemicals.Causes: breathing problems, headache, sore throat, dizziness, eye irritation in those sensitive to low levels.Chronic exposure to higher levels can lead to cancer.RadonNaturally occurring from radioactive decay of U-238.Occurs in soils, bedrock and can get into homes through cracks.Can’t get out and builds upCan lead to lung cancer
421, 1, 1- Nitrogen Oxides: Tobacco Smoke Carbon Monoxide Para-dichlorobenzene: air fresheners, moth balls; cancersTetrachloroethylene: dry cleaning residue; nerve, liver, kidney problemsChloroform: chlorine-treated hot water; cancersFormaldehyde: from processed wood; eye, nose, throat, lung irritant1, 1, 1-Trichloroethane: aerosals; dizziness, irregular breathingBenzo-a-pyrene: from smoke; lung cancerNitrogen Oxides:Gas ovens, kerosene heaters, un-vented gas burning; lung irritation, headachesStyrene: from carpet/plastic. Kidney/liver problemsTobacco SmokeAsbestos: old floor tile,Pipe insulation;lung problems, cancerRadon-222: from soils, lung diseaseCarbon MonoxideMethylene Chloride: paint stripper, thinner; nerve, diabetes
43SolutionsIndoor Air PollutionPreventionCleanupCover ceiling tiles and lining of AC ducts to prevent release of mineral fibersUse adjustable fresh air vents for work spacesBan smoking or limit it to well-ventilated areasIncrease intake of outside airChange air more frequentlySet stricter formaldehyde emissions standards for carpet, furniture, and building materialsCirculate building’s air through rooftop greenhousesPrevent radon infiltrationUse exhaust hoods for stoves and appliances burning natural gasUse office machines in well-ventilated areasUse less polluting substitutes for harmful cleaning agents, paints, and other productsInstall efficient chimneys for wood-burning stoves
44Particulates - Aka: particulate matter (PM) What are they? aerosols or fine particles, are tiny particles of solid (a smoke) or liquid (an aerosol) suspended in a gas.Size: < 10 nm - > 100 µm in diameter.Who do they effect? Sensitive populations such as children, the elderly, and individuals suffering from respiratory disease.
45Particulate Matter (PM) Larger particles are generally filtered in the nose and throat and do not cause problems.PM smaller than about 10 µm, referred to as PM10, can settle in the bronchi and lungs and cause health problems.
46Particulate Matter (PM) Includes a wide range of pollutants –road dustdiesel sootfly ashwood smokesulfate aerosols (suspended as particles in the air)These particles are a mixture of visible and microscopic solid particles and minute liquid droplets known as aerosols.
47Take a deep breath… Asthma: on the rise! WHY?? Varying opinions: Overly sterile environment as children; don’t build up natural immunityExposure to allergensGenetic make upExposure to pollutionLung cancerChronic bronchitisEmphysema
48National Ambient Air Quality Standards (NAAQS) Standards established by the EPA that apply for outdoor air throughout the country.Primary standards are designed to protect human health.Secondary standards are designed to protect public welfare (e.g. building facades, visibility, crops, and domestic animals).
49EPA’s watchful eyeNAAQS requires the EPA to set standards on six criteria pollutants:Ozone (O3)Particulate MatterCarbon monoxide (CO)Sulfur dioxide (SO2)Nitrogen oxides (NOx)Lead (Pb)
50Temperature Inversions (pg. 442) and Heat Islands (online activity)
51Temperature Inversion Warmer airInversion layerIncreasing altitudeCool layerMountainMountainValleyDecreasing temperatureTraps pollutants near surface. Mountains prevent wind in area and shadow sun to keep lower air cool.
52Temperature Inversion Descending warm air massInversion layerIncreasing altitudeSea breezeMountainrangeDecreasing temperatureTraps pollutants near surface. Mountains prevent pollutants leaving. Sea breeze blows in, not out This is what is happening in LA Video clip
54Stationery Source Air Pollution SolutionsStationery Source Air PollutionPreventionDispersion or CleanupBurn low-sulfurcoalDisperseemissions abovethermal inversionlayer with tallsmokestacksRemove sulfurfrom coalConvert coalto a liquid orgaseous fuelRemovepollutants aftercombustionShift to lesspolluting fuelsTax each unitof pollutionproduced
55Out-put or Control Methods See text pg Fig 20-18
57BagsCleaned gasDirty gasDust dischargeBaghouse Filter – only one to remove hazardous fine particles
58Wet Scrubber – Expensive Dirty gasCleaned gasCleanwaterWetgasDirty waterRemove 98% of SO2 andPM from emissionsWet Scrubber – Expensive
59Cyclone Separator - Cheap Cleaned gasDirty gasDoes NOT produce hazardousmaterials like otherDust dischargeCyclone Separator - Cheap
60Solutions for mobile emissions Motor Vehicle PollutionsSolutions for mobile emissionsPreventionCleanupMass transitEmission controldevicesBicycles and walkingLess polluting enginesLess polluting fuelsImprove fuel efficiencyCar exhaustInspectionstwice a yearGet older, pollutingcars off the roadGive buyers tax write-offs for buying low-polluting, energy-efficient vehiclesRestrict driving inpolluted areasStricter emissionstandards
61SolutionsAir PollutionPreventionCleanupImprove energy efficiencyto reduce fossil fuel useReduce povertyDistribute cheap and efficient cookstoves to poor families in developing countriesRely more on lower-polluting natural gasRely more on renewable energy (especially solar cells, wind, and solar-produced hydrogen)Reduce or ban indoor smokingDevelop simple and cheap test for indoor pollutants such as particulates, radon, and formaldehydeTransfer technologies for latest energy efficiency, renewable energy, and pollution prevention to developing countries.
62Clean Air Acts US Congress in 1970, 1977, 1990 EPA regulation of emissions that contribute to global warming, ozone depletion and air pollution. View clipYou should read ALL case studies in the chapter!Ea: The Bad Old Days, A Burning Controversy and section 20-7 specifically.
63VI. Pollution (25-30%) Air pollution Sources-primary and secondary (20.2 & air pollution lab)major air pollutants (20.2 & pollutant chart)measurement units (air pollution lab & emissions trading game)smog (20.3 & Demo: Smog in a jar)acid deposition-causes and effects (20.4, pH/acid rain lab, video)heat islands (online activity) and temperature inversions (20.3)indoor air pollution (20.5 & air particulate lab)remediation and reduction strategies (air pollution allowance trading article, emissions trading game) and Fig )Clean Air Act and other relevant laws (Law sheet, NAAQS)