2Core Case Study: South Asia’s Massive Brown Cloud Asian Brown CloudCausesclearing and burning forest for planting cropsBurning of coal, diesel, and other fossil fuels in industries , vehicles and homesChemical composition1/3rd of it is dust, smoke, and ashRest is acidic compounds, soot, toxic metals (mercury and lead), hundreds of organic compounds and fly ashAreas impactedmuch of India, Bangladesh, the industrial heart of China, the Open Sea east of this areaPhotosynthesis has been reduced by 7-10%Acid in the haze fall to the surface and damage crops, trees, and aquatic life
3The Asian Brown Cloud Air pollution connects the world On certain days25% of particulate matter77% of black carbon33% of toxic mercury in the skiesabove LA can be traced toChinaSteps taken in China and India toreduce air pollutionstrict pollution controls standards for coal-burning industriesshifting from coal to cleaner burning natural gas
518-1 The Atmosphere Consists of Several Layers Atmosphere varies inDensityThe air we breathe at sea level is denser than the air on top of the world’s highest mountains.Atmospheric pressureDecreases with altitude because they are fewer gas molecules at higher levels
6Earth’s Atmosphere Compared to the size of the Earth (12000 km) Shuttle Images of the AtmosphereThese images highlight the difference in the atmosphere before and after the. Showing the earth’s limb at sunset, first in September 1984, the atmosphere is relatively clear. The second image, taken in August of 1991, a little more than a month after the eruption, shows distinct layers of aerosols in the upper reaches of the atmosphere. These aerosols eventually made their way around the globe, contributing to a temporary worldwide cooling.Images Courtesy: NASA/ JSCJune 15, 1991 the eruption of Mt. Pinatubo, one of the most destructive volcanic eruptions of the last century. Found on the Bataan Peninsula on the island of Luzon in the Philippines, the volcano had been dormant for 500 years when clouds of sulfur dioxide and tons of ash spewed from the crater. Ultimately over 600 lives were lost in the explosion and its aftermath.Compared to the size of the Earth (12000 km)The atmosphere is very thin (120 km)or(75 miles)After Mt. Pinatubo eruption 1991
7Atmospheric LayersAurora, caused by collisions between protons and electrons from the Sun and oxygen and nitrogen atoms in the atmosphere.ThermosphereThis layer extends as high as 1000 km. Temperature increases rapidly after about 88 km.Meteor burning upThe atmosphere consists of layers around the Earth, each one defined by the way temperature changes within its limits.The layer boundaries are:TropopauseStratopauseMesopauseThe outermost, the thermosphere, thins slowly, fading into space with no boundary.MesosphereTemperature is constant in the lower mesosphere, but decreases steadily with height above 56 km.StratosphereTemperature is stable to20 km, then increases due to absorption of UV by the thin layer of ozone.TroposphereAir mixes vertically andhorizontally. All weatheroccurs in this layer.
8Air Movements in the Troposphere Play a Key Role in Earth’s Weather and Climate This is where we live8 to 14.5 kilometers high (5 to 9 miles)the temperature drops from about 17 to -52 degrees Celsius75–80% of the earth’s air massmost denseCloset to the earth's surfaceRising and falling air currents: weather and climateInvolved in chemical cycling
9Composition Nitrogen (N2, 78%) Oxygen (O2, 21%) Argon (Ar, 1%) myriad of other very influential components are also present which include the Water (H2O, 0 - 7%), "greenhouse" gases or Ozone (O3, %), Carbon Dioxide (CO2, %),
10The Stratosphere Is Our Global Sunscreen extends to 50 kilometers (31 miles) highdry and less densetemperature in this region increases gradually to -3 degrees Celsius, due to the absorption of ultraviolet radiationozone layer absorbs and scatters the solar ultraviolet radiationninety-nine percent of "air" is located in first two layersevery 1000-m 11% less air pressureSimilar composition to the troposphere, with 2 exceptionsMuch less waterO3, ozone layer, filters UV
11Natural Capital: The Earth’s Atmosphere Is a Dynamic System with Four Layers Figure 18.3Natural capital: The earth’s atmosphere is a dynamic system that includes four layers. The average temperature of the atmosphere varies with altitude (red line). Most UV radiation from the sun is absorbed by ozone (O3), found primarily in the stratosphere in the ozone layer 17–26 kilometers (10–16 miles) above sea level. Question: Why do you think the temperature falls and rises twice, going from lower to higher altitudes?
13O3 -The Good (15 - 40 km) blocks solar UV l<290 nm Beneficial Ozone that forms in the stratosphere protects life on earth by filtering out most of the incoming harmful UV radiation emitted by the sun
14O3 -The Bad 6-10 km : greenhouse gas absorbs IR emitted by Earth O3 →O3 (v=1)Harmful or Photochemical ozone forms in the troposphere when various air pollutants undergo chemical reactions under the influence of sunlight. Ozone in the atmosphere near the earth’s surface damages plants, lung tissue, and some materials such as rubber.It is a strong oxidant and respiratory irritant.Ground level ozone results primarily from motor-vehicle exhaust
1618-2 Air Pollution Comes from Natural and Human Sources The presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems, or human-made material.Natural sourcesDust blown by windPollutants from wildfires and volcanoesVolatile organics released by plantsWithdrawing groundwater
17Air Pollution Comes from Natural and Human Sources Human sources: mostly in industrialized and/or urban areasStationary sourcesMobile sources
19Most suspended particles H2O2 O3 PANs Most NO3− and SO42− salts Primary PollutantsSecondary PollutantsCOCO2SO2NONO2Most hydrocarbonsSO3HNO3H2SO4Most suspended particlesH2O2O3PANsMost NO3− and SO42− saltsSourcesNaturalStationaryFigure 18.4Sources and types of air pollutants. Human inputs of air pollutants come from mobile sources (such as cars) and stationary sources (such as industrial and power plants). Some primary air pollutants react with one another and with other chemicals in the air to form secondary air pollutants.MobileFig. 18-4, p. 472
20Case Study: Air Pollution in the Past: The Bad Old Days Discovery of fireMiddle Ages1700’s - Industrial RevolutionLondon, England1850s dense mixture of coal smoke and fog1880- a prolonged coal fog killed an estimated 2,200 people1952: yellow fog lasted for 5 days and killed 4, ,000 LondonersClean Air Act of 1956
21Case Study: Air Pollution in the Past: The Bad Old Days (2) United States1948: Donora, PA; first U.S. air pollution disaster1963: New York CityGlobal problemUrban areas in China, India and parts of Eastern Europe that depend on coal in industries and in some homes face air pollution levels similar to those in London and America in the 1950’s
22Some Pollutants in the Atmosphere Combine to Form Other Pollutants Primary pollutantsAre harmful chemicals emitted directly into the air from natural processes and human activities.Secondary pollutantsPrimary pollutants react with one another and with the basic components of air to form new harmful chemicalsAir quality improving in developed countriesMuch more needs to be done in developing countriesIndoor pollution: big threat to the poor
23Indoor Air PollutionThese children are working in a plastic factory in an urban slum in Bangladesh.
24What Are the Major Outdoor Air Pollutants? Carbon oxidesCarbon monoxide (CO)Colorless and highly toxic that forms during the incomplete combustion of carbon-containing materials. Reacts with hemoglobin in blood cells reduces the ability to transport oxygen.SourcesMotor vehicles exhaust, burning of forest and grasslands, tobacco smoke, and open fires and inefficient stoves used for cooking.Carbon dioxide (CO2)Colorless, odorless gas.93% result of natural carbon cycleRest from burning fossil fuels and clearing CO2 absorbing forest and grasslands.Emissions have been rising since the industrial revolution
25What Are the Major Outdoor Air Pollutants? Nitrogen oxides (NO) and nitric acid (HNO3)Sources- automobiles, coal-burning plantsNO reacts with oxygen to form NO2 (reddish brown gas) NO and NO2 are collectively called NOxAcid depositionPhotochemical smogHuman health and environmental impactNitrous oxide (N2O) a greenhouse gas that is emitted from fertilizers and animal waste and by burning fossil fuels
26Major Outdoor Pollutants Sulfur dioxide (SO2) and sulfuric acid (H2SO4)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.
27What Are the Major Outdoor Air Pollutants? ParticulatesSuspended particulate matter (SPM)Variety of particles and droplets (aerosols) small and light enough to remain suspended in atmosphere for short periods (large particles) to long periodscause smoke, dust, and haze.SourcesBurning coal in power and industrial plants (40%), burning diesel and other fuels in vehicles (17%), agriculture (plowing, burning off fields), unpaved roads, construction.Human health and environmental impactNose 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.Reduces visibility; acid deposition of H2SO4 droplets candamage trees, soils, and aquatic life in lakes
28Suspended particulate matter consists of particles of solid matter and droplets of liquid, that are small and light enough to remain suspended in the atmosphere for period (larger the particle, the sooner it falls to earth). Suspended particles are found in a wide variety of types and sizes, ranging in diameter from micrometer to 100 micrometers ( a micrometer, or micron, is one millionth of a meter, or about inch) Since 1987, the EPA has focused on fine particles smaller than 10 microns ( known as PM-10). In 1997, the agency began focusing on reducing emissions of ultra fine particles w/ diameters less than 2.5 microns ( known as PM-2.5) because these particles are small enough to reach the lower part of the human lungs and contribute to respiratory disease.
29What Are the Major Outdoor Air Pollutants? Ozone (O3)Highly reactive, irritating gas with an unpleasant odor that forms in the troposphere as a major component of photochemical smogSources Chemical reaction with volatile organic compounds (VOCs, emitted mostly by cars and industries) and nitrogen oxides to form photochemical smogHuman and environmental impactBreathing 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.
30What Are the Major Outdoor Air Pollutants? Volatile organic compounds (VOCs)organic compounds (hydrocarbons) that evaporate easily, usually aromaticHydrocarbons and terpenesSourcesMethane, chlorofluorocarbon, benzene and proprane.vehicles (largest source), evaporation of solvents or fossil fuels, aerosols, paint thinners, dry cleaningHuman and environmental impacteye and respiratory irritants; carcinogenic; liver, CNS, or kidney damage; damages plants; lowered visibility due to brown haze; global warming
31Chemical Reactions That Form Major Outdoor Air Pollutants
32Statue Corroded by Acid Deposition and Other Forms of Air Pollution, RI, U.S.
33Natural Capital: Lichen Species, Vulnerability to Air Pollutants Red and yellow crustose lichens growing on slate rock in the foothills of the Sierra Nevada near Merced, California. 19th century coal miners took canaries w/ them into the mines- canaries stop singing when the air contained methane, which could ignite and explode. Lichens, which are not plants, consist of a fungus and an alga living together, usually in a mutually beneficial (mutualistic) partnership. These hardy pioneer species are are good biological indicators of air pollution because they are always absorbing air as a source of nourishment. A highly polluted area around an industrial plant may have no lichens or only gray-green crusty lichens. An area w/ moderate pollution may have orange crusty lichens on walls. Walls and trees in areas with fairly clean air may have leafy lichens. Because lichens are widespread, long lived, and anchored in place, they can also help track pollution to its source.Case Study: When is a Lichen Like a Canary
34Case Study: Lead Is a Highly Toxic Pollutant Does not break down in the environmentSolid toxic metal and its compounds, emitted into the atmosphere as particulate matter.SourcesPaint old houses), smelters (metal refineries), lead manufacture, storage batteries, leaded gasoline (being phased out in developed countries).Human health and environmental impactAccumulates 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. Can harm wildlife.
35Case Study: Lead Is a Highly Toxic Pollutant Reduction of lead (Pb)Unleaded gasolineUnleaded paint 1960Still problems2007: toys with Pb paint recalled2007 2/3rd of red long-lasting lipstick manufactured in the US contained surprisingly high levels of lead.Global ban on lead in gasoline and paint
36SOLUTIONS Lead Poisoning Prevention Control Phase out leaded gasoline worldwideReplace lead pipes and plumbing fixtures containing lead solderPhase out waste incinerationRemove leaded paint and lead dust from older houses and apartmentsBan use of lead solderSharply reduce lead emissions from incineratorsBan use of lead in computer and TV monitorsRemove lead from TV sets and computer monitors before incineration or land disposalBan lead glazing for ceramicware used to serve foodFigure 18.7Ways to help protect children from lead poisoning. Question: Which two of these solutions do you think are the most important? Why?Test for lead in existing ceramicware used to serve foodBan candles with lead coresTest existing candles for leadTest blood for lead by age 1Wash fresh fruits and vegetablesFig. 18-7, p. 476
37Burning Coal Produces Industrial Smog Chemical composition of industrial smogmixture of SO2, droplets of sulfuric acid, and a variety of suspended solid particles emitted by burning coalReduction of this smog in urban cities of the United StatesChina and smog
38How Pollutants Are Formed from Burning Coal and Oil, Leading to Industrial Smog
39Carbon monoxide (CO) and Ammonium sulfate [(NH4)2SO4]Ammonia (NH3)Sulfuric acid (H2SO4)Water vapor (H2O)Carbon monoxide (CO) andcarbon dioxide (CO2)Sulfur trioxide (SO 3 )Oxygen (O2)Sulfur dioxide (SO2)Burning coal and oilOxygen (O2)Figure 18.8How pollutants are formed from burning of coal and oil. The result is industrial smog (Concept 18-2).Sulfur (S) in coal and oilCarbon (C) in coal and oilFig. 18-8, p. 476
40Carbon monoxide (CO) and Ammonium sulfate [(NH4)2SO4]Ammonia (NH3)Sulfuric acid (H2SO4)Water vapor (H2O)Sulfur trioxide (SO 3 )Oxygen (O2)Sulfur dioxide (SO2)Sulfur (S) in coal and oilCarbon monoxide (CO) andcarbon dioxide (CO2)Carbon (C) in coal and oilBurning coal and oilOxygen (O2)Figure 18.8How pollutants are formed from burning of coal and oil. The result is industrial smog (Concept 18-2).Stepped ArtFig. 18-8, p. 476
41Sunlight Plus Cars Equals Photochemical Smog Chemical compositionis a mixture of air pollutants formed by the reaction of nitrogen oxides and volatile organic hydrocarbon compounds under the influence of lightVOCs + NO2 + Heat + Sunlight yieldsGround level O3 and other photochemical oxidantsAldehydesOther secondary pollutants
42A Model of How Pollutants That Make Up Photochemicals Are Formed
43Nitric oxide (NO) + Oxygen atom (O) PANS and other pollutantsVolatile organic compounds (VOCs)Ozone (O3)Oxygen (O2)Nitric oxide (NO)+Oxygen atom (O)Water vapor (H2O)HydrocarbonsUV radiationPeroxyacyl nitrates(PANs)Nitrogen dioxide (NO2)Oxygen (O2)Nitric oxide (NO)Figure 18.9A greatly simplified model of how pollutants that make up photochemical smog are formed.Oxygen (O2)Burning fossil fuelsNitrogen (N) in fossil fuelFig. 18-9, p. 477
44Global Outlook: Photochemical Smog in Santiago, Chile
45How can trees Contribute to Photochemical Smog? Trees certainly have environmental benefitsEmit oxygen, absorb CO2, provide shade, and help absorb and remove various pollutants from the air.Some trees (some oak species, sweet gums, Poplars, and Kudzu) in and around urban areas play a large role in smog formationThey emit VOCs (like isoprene) that are ingredients in the development of photochemical smog.Plants in urban areas should be trees that emit low levels of VOCs.
46Several Factors Can Decrease or Increase Outdoor Air Pollution Outdoor air pollution may be decreased bySettling of particles due to gravityRain and snowSalty sea spray from the oceanWindsChemical reactions
47Several Factors Can Decrease or Increase Outdoor Air Pollution Outdoor air pollution may be increased byUrban buildingsHills and mountainsHigh temperaturesEmissions of VOCs from certain trees and plantsGrasshopper effectTemperature inversions
49Descending warm air mass Warmer airDescending warm air massInversion layerInversion layerSea breezeIncreasing altitudeFigure 18.11A temperature inversion, in which a warm air layer sits atop a cooler air layer, can take place in either of two sets of topography and weather conditions. Air pollutants can build to harmful levels during an inversion, which can occur during cold, cloudy weather in a valley surrounded by mountains (left). Frequent and prolonged temperature inversions can also occur in an area with a sunny climate, light winds, mountains on three sides, and the ocean on the other (right). A layer of descending warm air from a high-pressure system prevents ocean-cooled air near the ground from ascending enough to disperse and dilute pollutants. Because of their topography, Los Angeles, California (USA), and Mexico City, Mexico, have frequent temperature inversions, many of them prolonged, during the summer and fall.Decreasing temperatureFig , p. 478
5218-3 Acid Disposition Is a Serious Regional Air Pollution Problem Acid deposition, acid rainLocal versus regional problemsTall smokestacks reduce local air pollution by increases region air pollution downwindEffects of prevailing windsWhere is the worst acid deposition?
53Acid Deposition Formation When gas pollutants e.g. carbon dioxide, sulfur dioxide, nitrogen dioxide dissolve in rain water, various acids are formed.CO2 + H2O H2CO3 (carbonic acid)SO2 + H2O H2SO3 (sulfurous acid)NO2 + H2O HNO2 (nitrous acid) HNO3 (nitric acid)Sulfuric acid is responsible for about two-thirds of the acid deposition damage in the world and nitric acid the remaining one-third. In urban areas where NOx are released by the numerous vehicles, the damage from each type is nearly equal.
54Causes of Acid RainSulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes of acid rain.In the US, About 2/3 of all SO2 and 1/4 of all NOx comes from electric power generation that relies on burning fossil fuels like coal.
55Natural Capital Degradation: Acid Deposition, Acid Rain
56pH measurements in relation to major coal-burning and industrial plants. (Normal rain has a pH of 5.6)
57Current and Possible Future Acid Rain Problem Areas
58Figure 18.13Regions where acid deposition is now a problem and regions with the potential to develop this problem (Concept 18-3). Such regions have large inputs of air pollution (mostly from power plants, industrial plants, and ore smelters) or are sensitive areas with soils and bedrock that cannot neutralize (buffer) inputs of acidic compounds. Question: Do you live in or near an area that is affected by acid deposition or any area that is likely to be affected by acid deposition in the future? (Data from World Resources Institute and U.S. Environmental Protection Agency)Potential problem areas because of sensitive soilsPotential problem areas because of air pollution: emissions leading to acid depositionCurrent problem areas (including lakes and rivers)Fig , p. 480
59Increased AcidityDry deposited gases and particles can also be washed from trees and other surfaces by rainstorms.The runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone.
60Effects of Acid RainHas a variety of effects, including damage to forests and soils, fish and other living things, materials, and human health.Also reduces how far and how clearly we can see through the air, an effect called visibility reduction.Effects of acid rain are most clearly seen in the aquatic environmentsMost lakes and streams have a pH between 6 and 8
61Buffering CapacityAcid rain primarily affects sensitive bodies of water, which are located in watersheds whose soils have a limited “buffering capacity”Lakes and streams become acidic when the water itself and its surrounding soil cannot buffer the acid rain enough to neutralize it.
62In areas where buffering capacity is low, acid rain also releases aluminum ions from soils into lakes and streams; aluminum is highly toxic to many species of aquatic organisms referred to as acid shock.
63Effects on WildlifeGenerally, the young of most species are more sensitive to environmental conditions than adults.At pH 5, most fish eggs cannot hatch.At lower pH levels, some adult fish die.Some acid lakes have no fish.The eggs and juveniles of sensitive species are susceptible to a pH of 5, thus interfering w/ reproduction. The acids therefore decrease biodiversity by reducing food available at lower trophic levels, which may have a resultant reduction of biomass. Sensitive fish species include trout and salmon. Trash fish species, such as gar, and carp, are more pollutant tolerant.
64Acid Rain and Forests Acid rain does not usually kill trees directly. Instead, it is more likely to weaken trees by damaging their leaves, limiting the nutrients available to them, or exposing them to toxic substances slowly released from the soil.Vegetation is impacted by acid deposition. Acid directly damages cuticles (the waxy coat on leaves) on plant leaves, which makes the plants more susceptible to infections from bacteria, nematodes, and fungi. As a result, not only are forest damaged, but crop yields are reduced in acidified ecosytesms. .
65MongoliaGermanyForest damage is exemplified by the devastation in the Black forest in Germany.
66Great Smoky Mountains, NC Effects of Acid RainForest damage is exemplified by the devastation in the Great Smokey Mountains in the U.S.Great Smoky Mountains, NC
67NutrientsAcidic water dissolves the nutrients and helpful minerals in the soil and then washes them away before trees and other plants can use them to grow.Acid rain also causes the release of substances that are toxic to trees and plants, such as aluminum, into the soil.
68Acid Deposition Has a Number of Harmful Effects Human respiratory disordersAquatic ecosystems affectedRelease of toxic metalToxic lead and mercuryLeaching of soil nutrientsLoss of crops and treesDamage to buildings, statues, and monuments
69Natural Capital Degradation: Air Pollution Damage to Trees in North Carolina, U.S.
70Solutions: Acid Deposition, Prevention and Cleanup
73Active Figure: Effect of air pollution in forests
7418-4 Indoor Air Pollution Is a Serious Problem Developing countriesIndoor burning of wood, charcoal, dung, crop residues, coal in open fires or unvented or poorly vented stovesPoor suffer the greatest riskDeveloped countriesIndoor air pollution is greater than outdoor air pollution
75ExposureTime spent in various environments in US and less-developed countries
76Indoor Air Pollution Is a Serious Problem Why?11 of the common air pollutants higher inside than outsideGreater in vehicles than outsideHealth risks magnified: people spend 70–98% of their time is indoors
77Indoor Air Pollution Is a Serious Problem Who are at greatest risk from indoor air pollution?Children under 5 and the elderlySickPregnant womenPeople with respiratory disorders or heart problemsSmokersFactory workers
78Indoor Air Pollution Is a Serious Problem Four most dangerous indoor air pollutantsTobacco smoke- most preventableFormaldehydeFound in many building material, and household products (plywood, particle board, paneling, high-gloss wood, drapes, furniture, carpets, wallpaper, wrinkle- free coating on permanent –press clothing)The chemical that causes most people in developed countries difficultyColorless extremely irritating chemicalCauses chronic breathing problems, dizziness, skin, eye, sinus irritation, rash, headaches, sore throats, wheezing and nauseaEPA estimates that 1 of every 5,000 people who live in manufactured homes for more than 10 years will develop cancer from formaldehyde exposure.
79Four most dangerous indoor air pollutants (cont) Radioactive radon-222 gasSeep into houses from underground rock depositsColorless odorless radioactive gas produced by the natural decay of uranium-238.lung tissue damage, lung cancerEstimated that 7,000 to 30,000 Americans die each year from radon-induced lung cancerOnly smoking causes more lung cancer deathsSmokers more at risk than non-smokersVery small particlesAsbestosIrritate the nose and throat, damage the lungs, aggravate asthma and bronchitis, and shorten life.
80Science: Sources and Paths of Entry for Indoor Radon-222 Gas
81(From: http://www.epa.gov/iaq/radon/zonemap.html) Zone pCi/L>4<2
82Indoor Air Pollution Is a Serious Problem Other possible indoor air pollutantsPesticide residuePb particlesLiving organisms and their excrementsE.g., Dust mites and cockroach droppingsAirborne spores of molds and mildews
83Science: Magnified View of a Household Dust Mite in a Dust Ball
85ChloroformPara-dichlorobenzeneTetrachloroethyleneSource: Chlorine-treated water in hot showers Possible threat: CancerSource: Air fresheners, mothball crystalsThreat: CancerSource: Dry-cleaning fluid fumes on clothesThreat: Nerve disorders, damage to liver and kidneys, possible cancerFormaldehydeSource: Furniture stuffing, paneling, particleboard, foam insulationThreat: Irritation of eyes, throat, skin, and lungs; nausea; dizziness1,1,1-TrichloroethaneSource: Aerosol spraysThreat: Dizziness, irregular breathingStyreneNitrogen oxidesSource: Carpets, plastic productsThreat: Kidney and liver damageSource: Unvented gas stoves and kerosene heaters, woodstovesThreat: Irritated lungs, children's colds, headachesBenzo- α -pyreneSource: Tobacco smoke, woodstovesThreat: Lung cancerParticulatesSource: Pollen, pet dander, dust mites, cooking smoke particlesThreat: Irritated lungs, asthma attacks, itchy eyes, runny nose, lung diseaseRadon-222Source: Radioactive soil and rock surrounding foundation, water supplyThreat: Lung cancerFigure 18.16Some important indoor air pollutants (Concept 18-4). Question: Which of these pollutants are you exposed to? (Data from U.S. Environmental Protection Agency)Tobacco smokeSource: CigarettesThreat: Lung cancer, respiratory ailments, heart diseaseAsbestosCarbon monoxideMethylene chlorideSource: Pipe insulation, vinyl ceiling and floor tiles Threat: Lung disease, lung cancerSource: Faulty furnaces, unvented gas stoves and kerosene heaters, woodstovesThreat: Headaches, drowsiness, irregular heartbeat, deathSource: Paint strippers and thinners Threat: Nerve disorders, diabetesFig , p. 484
86Sick Building Syndrome (SBS) vs Building Related Illness (BRI)
87Sick Building Syndrome A persistent set of symptoms in > 20% populationCauses(s) not known or recognizableComplaints/Symptoms relieved after exiting buildingLinked to inadequate ventilation, new buildings that contain chemicals such as formaldehyde from building products, or biological contaminants like mold or pollen.
88Complaints/Symptoms Headaches Fatigue Reduced Mentation Irritability Eye, nose or throat irritationDry SkinNasal CongestionDifficulty BreathingNose BleedsNausea
89Building Related Illness Clinically Recognized DiseaseExposure to indoor air pollutantsRecognizable Causes
91Respiratory system protection from air pollutants 18-5 Your Body’s Natural Defenses against Air Pollution Can Be OverwhelmedRespiratory system protection from air pollutantsHair in nose, cilia, mucus, sneezing, and coughingEffect of smoking and prolonged air pollution exposureChronic bronchitisEmphysema- irreversible damage to the air sacs in the lungs
92Major Components of the Human Respiratory System
93Normal Human Lungs and the Lungs of a Person Who Died of Emphysema
94Air Pollution Is a Big Killer 3 Million deaths per year world-wideMostly in AsiaMain causesHeart attacks, respiratory diseases, and lung cancerEPA: proposed stricter emission standards for diesel-powered vehiclesLink between international trade and air pollutionCargo ships and pollution
9618-6 Laws and Regulations Can Reduce Outdoor Air Pollution (1) United StatesClean Air Acts: 1970, 1977, and 1990EPANational ambient air quality standards (NAAQs) for 6 outdoor criteria pollutantsNational emission standards for 188 hazardous air pollutants (HAPs)Toxic Release Inventory (TRI)
971970 – Uniform Standards by Federal Govt. Clean Air ActOriginally signed 1963States controlled standards1970 – Uniform Standards by Federal Govt.Criteria PollutantsPrimary – Human health riskSecondary – Protect materials, crops, climate, visibility, personal comfort
98Clean Air Act 1990 version 1997 version Acid rain, urban smog, toxic air pollutants, ozone depletion, marketing pollution rights, VOC’s1997 versionReduced ambient ozone levelsCost $15 billion/year -> save 15,000 livesReduce bronchitis cases by 60,000 per yearReduce hospital respiratory admission 9000/year
99PREVENTING AND REDUCING AIR POLLUTION The Clean Air Acts in the United States havegreatly reduced outdoor air pollution fromsix major pollutants:Carbon monoxideNitrogen oxidesSulfur dioxidesSuspended particulate matter (less than PM-10)Tropospheric Ozone
100Laws and Regulations Can Reduce Outdoor Air Pollution (2) Good news in U.S.Decrease in emissionsUse of low-sulfur diesel fuelCuts pollutionDeveloping countriesMore air pollution
101Case Study: U.S. Air Pollution Can Be Improved Rely on cleanup more than prevention of pollutionRaise fuel-efficiency for cars, SUVs, and light trucksBetter regulation of emissions of motorcycles and two-cycle gasoline enginesRegulate air pollution for oceangoing ships in American ports
102Case Study: U.S. Air Pollution Can Be Improved (2) Why are airports exempt from many regulations?Regulate greenhouse gas emissionsUltrafine particles are not regulatedUrban O3 levels too high
103Case Study: U.S. Air Pollution Can Be Improved (3) What about indoor air pollution?Better enforcement of the Clean Air ActsIntense pressure needed from citizens to make improvements
104We Can Use the Marketplace to Reduce Outdoor Air Pollution Emission trading or cap-and-trade programMixed reactions to programSO2 emissions down significantlyNO2 will be tried in the future
105There Are Many Ways to Reduce Outdoor Air Pollution 1980 –2006SO2 emissions from U.S. electric power plants decreased by 66%NOx emissions by 41%Particulate emissions by 28%Older plants not governed by the same regulationsNew cars have better emissions
107Prevention of Air pollution Post combustion methodCatalytic converter to oxidize the sulfur to yield sulfur compounds.A lime scrubber in a smokestack may be usedIn a wet scrubber, a slurry of lime mixed w/ water is sprayed across the exiting gases. The sulfur mixes w/ the calcium, forming the calcium sulfate, which falls to the bottom of the smokestack as bottom ash.Most particulates are removed post combustion
108Electrostatic Precipitator Cleaned gasElectrodesFour commonly used output or control methods for removing particulates and SO2 from the exhaust gases of electrical power plants. All of these methods produce hazardous materials that must be disposed of safely, and except for cyclone separators, all of them are expensive.Electrostatic precipitators remove 99 percent of the particulates in coal emissions. They function by passing the coal emissions past a series of charged plates, thus charging the particulates, which then bind to an oppositely charged plate.Dust dischargeDirty gasElectrostatic Precipitator
109Bags Cleaned gas Dirty gas Baghouse Filter Dust discharge Bag filters are a series if bags, somewhat like a bag in a vacuum cleaner, which catch the particulates as they rise in the smoke. The bags are periodically emptied of their ash.Baghouse FilterDust discharge
110Cleaned gas Dirty gas Cyclone Separator Dust discharge Cyclone collectors create a vortex in a smokestack, causing the particles to collide and fall to the bottom of the stack as bottom ash.Cyclone SeparatorDust discharge
111Dirty gas Cleaned gas Clean water Wet gas Wet Scrubber Dirty water Modern wet scrubbers remove 98% of the SO2 and 98% of the particulate matter in smokestack emissions, but they are expensive to install and maintain.Wet ScrubberDirty water
112Solutions: Motor Vehicle Air Pollution, Prevention and Cleanup
113Reducing Indoor Air Pollution Should Be a Priority Greater threat to human health than outdoor pollutionWhat can be done?PreventionCleanup
114Movement of Air Into / Out of Homes Amount of air available to dilute pollutantsimportant indicator of the likely contaminant concentrationIndoor air can mix with outside air by three mechanismsinfiltrationnatural ventilationforced ventilation
115Movement of Air Into / Out of Homes Natural ventilationair exchange that occurs when windows or doors are opened to increase air circulationForced ventilationmechanical air handling systems used to induce air exchange using fans and blowersTrade-offscut infiltration to decrease heating and cooling costs vs. indoor air quality problems
116Solutions: Indoor Pollution, Prevention and Cleanup or Dilution
117What Can You Do? Indoor Pollution: Ways to Reduce Your Exposure
118Solutions: Air Pollution, Ways to Prevent It Over the Next 30–40 Years