chapter 20 air pollution. overview of chapter 20 o atmosphere as a resource o types and sources of...
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Chapter 20Chapter 20Air PollutionAir Pollution
Overview of Chapter 20Overview of Chapter 20
o Atmosphere as a ResourceAtmosphere as a Resourceo Types and Sources of Air PollutionTypes and Sources of Air Pollution
• Major Classes of Air PollutantsMajor Classes of Air Pollutants• Sources of Outdoor Air PollutantsSources of Outdoor Air Pollutants• Urban Air PollutionUrban Air Pollution
o Effects of Air PollutionEffects of Air Pollutiono Controlling Air Pollution in the USControlling Air Pollution in the US
Atmosphere as a ResourceAtmosphere as a Resourceo Atmospheric Atmospheric
CompositionComposition• Nitrogen 78.08%Nitrogen 78.08%• Oxygen 20.95%Oxygen 20.95%• Argon 0.93%Argon 0.93%• Carbon dioxide 0.04%Carbon dioxide 0.04%
o Ecosystem servicesEcosystem services• Blocks UV radiationBlocks UV radiation• Moderates the Moderates the
climateclimate• Redistributes water in Redistributes water in
the hydrologic cycle the hydrologic cycle
Types and Sources of Air Types and Sources of Air PollutionPollution
o Air PollutionAir Pollution• Chemicals added to the atmosphere by Chemicals added to the atmosphere by
natural events or human activities in high natural events or human activities in high enough concentrations to be harmful enough concentrations to be harmful
o Two categoriesTwo categories• Primary Air PollutantPrimary Air Pollutant
• Harmful substance that is emitted directly into Harmful substance that is emitted directly into the atmosphere the atmosphere
• Secondary Air PollutantSecondary Air Pollutant• Harmful substance formed in the atmosphere Harmful substance formed in the atmosphere
when a primary air pollutant reacts with when a primary air pollutant reacts with substances normally found in the atmosphere or substances normally found in the atmosphere or with other air pollutants with other air pollutants
Major Air PollutantsMajor Air Pollutants
Major Classes of Air PollutantsMajor Classes of Air Pollutants
o Particulate MaterialParticulate Materialo Nitrogen OxidesNitrogen Oxideso Sulfur OxidesSulfur Oxideso Carbon OxidesCarbon Oxideso HydrocarbonsHydrocarbonso OzoneOzone
Particulate MaterialParticulate Material
o Thousands of different solid or liquid Thousands of different solid or liquid particles suspended in airparticles suspended in air• Includes: soil particles, soot, lead, asbestos, Includes: soil particles, soot, lead, asbestos,
sea salt, and sulfuric acid droplets sea salt, and sulfuric acid droplets
o Dangerous for 2 reasonsDangerous for 2 reasons• May contain materials with toxic or May contain materials with toxic or
carcinogenic effectscarcinogenic effects• Extremely small particles can become Extremely small particles can become
lodged in lungslodged in lungs
Nitrogen and Sulfur OxidesNitrogen and Sulfur Oxides
o Nitrogen OxidesNitrogen Oxides• Gases produced by the chemical Gases produced by the chemical
interactions between atmospheric nitrogen interactions between atmospheric nitrogen and oxygen at high temperatureand oxygen at high temperature
• ProblemsProblems• Greenhouse gases Greenhouse gases • Cause difficulty breathingCause difficulty breathing
o Sulfur OxidesSulfur Oxides• Gases produced by the chemical Gases produced by the chemical
interactions between sulfur and oxygen interactions between sulfur and oxygen • Causes acid precipitationCauses acid precipitation
Carbon Oxides and Carbon Oxides and HydrocarbonsHydrocarbons
o Carbon OxidesCarbon Oxides• Gases carbon monoxide (CO) and carbon Gases carbon monoxide (CO) and carbon
dioxide (COdioxide (CO22) ) • Greenhouse gasesGreenhouse gases
o HydrocarbonsHydrocarbons• Diverse group of organic compounds that Diverse group of organic compounds that
contain only hydrogen and carbon (ex: CHcontain only hydrogen and carbon (ex: CH44- - methane)methane)
• Some are related to photochemical smog Some are related to photochemical smog and greenhouse gasesand greenhouse gases
OzoneOzone
o Tropospheric OzoneTropospheric Ozone• Man- made pollutant in the lower Man- made pollutant in the lower
atmosphereatmosphere• Secondary air pollutantSecondary air pollutant• Component of photochemical smogComponent of photochemical smog
o Stratospheric OzoneStratospheric Ozone• Essential component that screens out UV Essential component that screens out UV
radiation in the upper atmosphereradiation in the upper atmosphere• Man- made pollutants (ex: CFCs) can Man- made pollutants (ex: CFCs) can
destroy itdestroy it
Sources of Outdoor Air PollutionSources of Outdoor Air Pollution
o Two main Two main sourcessources• TransportationTransportation• IndustryIndustry
o Intentional forest Intentional forest fires is also highfires is also high
Urban Air PollutionUrban Air Pollutiono Photochemical Smog (ex: Los Angeles below)Photochemical Smog (ex: Los Angeles below)
• Brownish-orange haze formed by chemical reactions Brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons involving sunlight, nitrogen oxide, and hydrocarbons
Formation of Photochemical Formation of Photochemical SmogSmog
Sources of Smog in Los AngelesSources of Smog in Los Angeles
Case-In-Point Air Pollution in Beijing Case-In-Point Air Pollution in Beijing and Mexico Cityand Mexico City
o Beijing (left)Beijing (left)o Mexico City (above)Mexico City (above)
Effects of Air PollutionEffects of Air Pollution
o Low level exposureLow level exposure• Irritates eyesIrritates eyes• Causes inflammation of respiratory tractCauses inflammation of respiratory tract
o Can develop into chronic respiratory Can develop into chronic respiratory diseasesdiseases
Health Effects of Air PollutionHealth Effects of Air Pollution
o Sulfur Dioxide and Particulate materialSulfur Dioxide and Particulate material• Irritate respiratory tract and impair ability Irritate respiratory tract and impair ability
of lungs to exchange gasesof lungs to exchange gaseso Nitrogen DioxidesNitrogen Dioxides
• Causes airway restrictionCauses airway restrictiono Carbon monoxideCarbon monoxide
• Binds with iron in blood hemoglobinBinds with iron in blood hemoglobin• Causes headache, fatigue, drowsiness, Causes headache, fatigue, drowsiness,
deathdeatho OzoneOzone
• Causes burning eyes, coughing, and chest Causes burning eyes, coughing, and chest discomfortdiscomfort
Children and Air PollutionChildren and Air Pollution
o Greater health threat to children than Greater health threat to children than adultsadults• Air pollution can restrict lung developmentAir pollution can restrict lung development• Children breath more often than adultsChildren breath more often than adults
o Children who live in high ozone areas Children who live in high ozone areas are more likely to develop asthmaare more likely to develop asthma
Controlling Air Controlling Air Pollution in USPollution in US
o Smokestacks with Smokestacks with electrostatic precipitator electrostatic precipitator (right)(right)
Without Without Electrostatic Electrostatic precipitatorprecipitator
With Electrostatic With Electrostatic precipitatorprecipitator
Controlling Air Controlling Air Pollution in the USPollution in the US
o Smokestacks with Smokestacks with scrubbers (right)scrubbers (right)
o Particulate material Particulate material can also be controlled can also be controlled by proper excavating by proper excavating techniquestechniques
Controlling Air Pollution in the USControlling Air Pollution in the US
o Phase I Vapor Recovery System for Phase I Vapor Recovery System for gasolinegasoline
The Clean Air ActThe Clean Air Act
o Authorizes EPA to Authorizes EPA to set limits on amount set limits on amount of specific air of specific air pollutants permittedpollutants permitted
o Focuses on 6 Focuses on 6 pollutants:pollutants:• lead, particulate lead, particulate
matter, sulfur matter, sulfur dioxide, carbon dioxide, carbon monoxide, nitrogen monoxide, nitrogen oxides, and ozoneoxides, and ozone
o Act has led to Act has led to decreases!decreases!
Other Ways to Improve Air QualityOther Ways to Improve Air Quality
o Reduce sulfur content in gasoline from Reduce sulfur content in gasoline from its current average of 330 ppm to 30 its current average of 330 ppm to 30 ppmppm• Sulfur clogs catalytic convertersSulfur clogs catalytic converters
o Require federal emission standards for Require federal emission standards for all passenger vehiclesall passenger vehicles• Including SUVs, trucks and minivansIncluding SUVs, trucks and minivans
o Require emission testing for all vehiclesRequire emission testing for all vehicles• Including dieselIncluding diesel
Ozone Depletion in StratosphereOzone Depletion in Stratosphere
o Ozone Protects earth from UV radiationOzone Protects earth from UV radiation• Part of the electromagnetic spectrum with Part of the electromagnetic spectrum with
wavelengths just shorter than visible light wavelengths just shorter than visible light
Ozone Depletion in StratosphereOzone Depletion in Stratosphere
o Ozone thinning/holeOzone thinning/hole• First identified in 1985 First identified in 1985
over Antarcticaover Antarctica
o Caused by Caused by • human-produced human-produced
bromine and chlorine bromine and chlorine containing chemicalscontaining chemicals
• Ex: CFCsEx: CFCs
Ozone Depletion in StratosphereOzone Depletion in Stratosphere
o Hole over Antarctica requires two Hole over Antarctica requires two conditions:conditions:• Sunlight just returning to polar regionSunlight just returning to polar region• Circumpolar vortex- a mass of cold air that Circumpolar vortex- a mass of cold air that
circulates around the southern polar region circulates around the southern polar region • Isolates it from the warmer air in the rest of the Isolates it from the warmer air in the rest of the
planet planet
o Polar stratospheric clouds formPolar stratospheric clouds form• Enables Cl and Br to destroy ozoneEnables Cl and Br to destroy ozone
Effects of Ozone DepletionEffects of Ozone Depletion
o Higher levels of UV-Higher levels of UV-radiation hitting the radiation hitting the earthearth• Eye cataractsEye cataracts• Skin cancer (right)Skin cancer (right)• Weakened immunityWeakened immunity
o May disrupt May disrupt ecosystemsecosystems
o May damage crops May damage crops and forestsand forests
Recovery of Ozone LayerRecovery of Ozone Layer
o Montreal Protocol (1987)Montreal Protocol (1987)• Reduction of CFCsReduction of CFCs• Started using HCFCs (greenhouse gas)Started using HCFCs (greenhouse gas)
o Phase out of all ozone destroying Phase out of all ozone destroying chemicals is underway globallychemicals is underway globally
o Satellite pictures in 2000 indicated that Satellite pictures in 2000 indicated that ozone layer was recoveringozone layer was recovering
o Full recovery will not occur until 2050Full recovery will not occur until 2050
Acid DepositionAcid Deposition
o Sulfur dioxide and nitrogen dioxide Sulfur dioxide and nitrogen dioxide emissions react with water vapor in the emissions react with water vapor in the atmosphere and form acids that return atmosphere and form acids that return to the surface as either dry or wet to the surface as either dry or wet deposition deposition
o pH scalepH scale
How Acid Deposition DevelopsHow Acid Deposition Develops
Effects of Acid DepositionEffects of Acid Deposition
o Declining Aquatic Declining Aquatic Animal PopulationsAnimal Populations
o Thin-shelled eggs Thin-shelled eggs prevent bird prevent bird reproductionreproduction• Because calcium is Because calcium is
unavailable in acidic unavailable in acidic soilsoil
o Forest declineForest decline• Ex: Black forest in Ex: Black forest in
Germany (50% is Germany (50% is destroyed)destroyed)
Acid Deposition and Forest Acid Deposition and Forest DeclineDecline
Air Pollution Around the WorldAir Pollution Around the World
o Air quality is deteriorating Air quality is deteriorating rapidly in developing countriesrapidly in developing countries
o Shenyang, ChinaShenyang, China• Residents only see sunlight a few Residents only see sunlight a few
weeks each yearweeks each year
o Developing countries have Developing countries have older carsolder cars• Still use leaded gasolineStill use leaded gasoline
o 5 worst cities in world5 worst cities in world• Beijing, China; Mexico City, Beijing, China; Mexico City,
Mexico; Shanghai, China; Tehran, Mexico; Shanghai, China; Tehran, Iran; and Calcutta, India Iran; and Calcutta, India
Long Distance Transport of Air Long Distance Transport of Air PollutantsPollutants
Indoor Air Indoor Air PollutionPollution
o Pollutants can be Pollutants can be 5-100X greater 5-100X greater than outdoorsthan outdoors
o Most common:Most common:• Radon, cigarette Radon, cigarette
smoke, carbon smoke, carbon monoxide, monoxide, nitrogen dioxide, nitrogen dioxide, formaldehyde formaldehyde pesticides, lead, pesticides, lead, cleaning cleaning solvents, ozone, solvents, ozone, and asbestos and asbestos
Indoor Air Pollution - RadonIndoor Air Pollution - Radon