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Air PollutionAir Pollution
Overview of Air PollutionOverview of Air Pollution
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 climateModerates the climate• Redistributes water in Redistributes water in
the hydrologic cycle the hydrologic cycle (water cycle). (water cycle).
Types and Sources of Air PollutionTypes and Sources of Air Pollution
o Air PollutionAir Pollution• Chemicals added to the atmosphere by natural Chemicals added to the atmosphere by natural
events or human activities in high enough events or human activities in high enough concentrations to be harmful concentrations to be harmful
o Two categoriesTwo categories• Primary Air PollutantPrimary Air Pollutant
• Harmful substance that is emitted directly into the Harmful substance that is emitted directly into the atmosphere atmosphere
• Secondary Air PollutantSecondary Air Pollutant• Harmful substance formed in the atmosphere when a Harmful substance formed in the atmosphere when a
primary air pollutant reacts with substances normally primary air pollutant reacts with substances normally found in the atmosphere or with other air pollutants found in the atmosphere or 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 Materialo Thousands of different solid or liquid particles Thousands of different solid or liquid particles
suspended in airsuspended in air• Includes: soil particles, soot, lead, Includes: soil particles, soot, lead,
asbestos, sea salt, and sulfuric acid asbestos, sea salt, and sulfuric acid droplets 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 Oxideso Nitrogen OxidesNitrogen Oxides
• Gases produced by the chemical interactions Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at high between atmospheric nitrogen and oxygen at high temperaturetemperature
• ProblemsProblems• Greenhouse gases Greenhouse gases • Cause difficulty breathingCause difficulty breathing
o Sulfur OxidesSulfur Oxides• Gases produced by the chemical interactions Gases produced by the chemical interactions
between sulfur and oxygen between sulfur and oxygen • Causes acid precipitationCauses acid precipitation
Carbon Oxides and HydrocarbonsCarbon Oxides and Hydrocarbonso Carbon OxidesCarbon Oxides
• Gases carbon monoxide (CO) and Gases carbon monoxide (CO) and carbon dioxide (COcarbon dioxide (CO22) )
• Greenhouse gasesGreenhouse gaseso HydrocarbonsHydrocarbons
• Diverse group of organic compounds Diverse group of organic compounds that contain only hydrogen and carbon that contain only hydrogen and carbon (ex: CH(ex: CH44- methane)- methane)
• Some are related to photochemical Some are related to photochemical smog and greenhouse gasessmog and greenhouse gases
OzoneOzoneo Tropospheric OzoneTropospheric Ozone
• Man-made pollutant in the lower atmosphere.Man-made pollutant in the lower atmosphere.• Secondary air pollutant.Secondary air pollutant.• Component of photochemical smog.Component of photochemical smog.
o Stratospheric OzoneStratospheric Ozone• Essential component that screens out UV Essential component that screens out UV
radiation in the upper atmosphere.radiation in the upper atmosphere.• Man-made pollutants (ex: CFCs) can destroy Man-made pollutants (ex: CFCs) can destroy
it!it!http://www.airinfonow.org/html/makingozone/o3play.htmhttp://www.airinfonow.org/html/makingozone/o3play.htm
Sources of Outdoor Air PollutionSources of Outdoor Air Pollution
o Two main sourcesTwo main sources• 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.
Photochemical SmogPhotochemical Smog
o Photochemical smogPhotochemical smog
Formation of Photochemical SmogFormation of Photochemical Smog
Sources of Smog in Los AngelesSources of Smog in Los Angeles
Case-In-Point Air Pollution in Beijing and Case-In-Point Air Pollution in Beijing and Mexico CityMexico 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 of lungs Irritate respiratory tract and impair ability of lungs
to exchange gasesto 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, deathCauses headache, fatigue, drowsiness, death
o 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 adultsGreater health threat to children than adults• 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 are Children who live in high ozone areas are more likely to develop asthmamore likely to develop asthma
Lung effectLung effect
http://www.airinfonow.org/html/lungattack/lungplay.htmhttp://www.airinfonow.org/html/lungattack/lungplay.htm
Controlling Air Pollution in Controlling Air Pollution in USUS
o Smokestacks with Smokestacks with electrostatic precipitator electrostatic precipitator (right)(right)
Without Without Electrostatic Electrostatic precipitatorprecipitator
With Electrostatic With Electrostatic precipitatorprecipitator
Controlling Air Pollution Controlling Air Pollution in the USin the US
o Smokestacks with Smokestacks with scrubbers (right)scrubbers (right)
o Particulate material can Particulate material can also be controlled by also be controlled by proper excavating proper excavating techniquestechniques
Controlling Air Pollution in the USControlling Air Pollution in the US
o Phase I Vapor Recovery System for gasolinePhase I Vapor Recovery System for gasoline
The Clean Air ActThe Clean Air Act
o Authorizes EPA to set Authorizes EPA to set limits on amount of limits on amount of specific air pollutants specific air pollutants permittedpermitted
o Focuses on 6 Focuses on 6 pollutants:pollutants:• lead, particulate matter, lead, particulate matter,
sulfur dioxide, carbon sulfur 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 its current Reduce sulfur content in gasoline from its current average of 330 ppm to 30 ppmaverage of 330 ppm to 30 ppm• Sulfur clogs catalytic convertersSulfur clogs catalytic converters• A A catalytic convertercatalytic converter is a vehicle emissions is a vehicle emissions
control device that converts toxic pollutants in exhaust control device that converts toxic pollutants in exhaust gas to less toxic pollutants.gas to less toxic pollutants.
o Require federal emission standards for all Require federal emission standards for all passenger vehiclespassenger 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 Stratosphereo Ozone Protects earth from UV radiationOzone Protects earth from UV radiation
• UV radiation: Part of the electromagnetic spectrum UV radiation: Part of the electromagnetic spectrum with wavelengths just shorter than visible light. with 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 Antarcticao 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 Stratosphereo Hole over Antarctica requires two conditions:Hole over Antarctica requires two 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 Isolates it from the warmer air in the rest
of the planet of the 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 chemicals Phase out of all ozone destroying chemicals is underway globallyis underway globally
o Satellite pictures in 2000 indicated that ozone Satellite pictures in 2000 indicated that ozone layer was recoveringlayer was recovering
o Full recovery will not occur until 2050Full recovery will not occur until 2050
Acid DepositionAcid Depositiono 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 to atmosphere and form acids that return to the surface as either dry or wet deposition the surface as either dry or wet 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 soilunavailable in acidic soilo Forest declineForest decline
• Ex: Black forest in Ex: Black forest in Germany (50% is Germany (50% is destroyed)destroyed)
Acid Deposition and Forest DeclineAcid Deposition and Forest Decline
Air Pollution Around the WorldAir Pollution Around the World
o Air quality is deteriorating rapidly Air quality is deteriorating rapidly in developing countriesin 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 older Developing countries have older carscars
• Still use leaded gasolineStill use leaded gasoline
o 5 worst cities in world5 worst cities in world• Beijing, China; Mexico City, Mexico; Beijing, China; Mexico City, Mexico;
Shanghai, China; Tehran, Iran; and Shanghai, China; Tehran, Iran; and Calcutta, India Calcutta, India
o Want to know where you should relocate to in order to avoid ground-level ozone pollution? According to the 2007 State of the Air report from the American Lung Association, The five cleanest cities are
o Boone, Iowao Bellingham, Washingtono Bloomington, Illinoiso Boise City, Idahoo Brunswick, Georgia
