Chapter 20 Air Pollution. Overview of Chapter 20 Atmosphere as a Resource Types and Sources of Air...
-
Upload
harvey-mills -
Category
Documents
-
view
224 -
download
3
Transcript of Chapter 20 Air Pollution. Overview of Chapter 20 Atmosphere as a Resource Types and Sources of Air...
Chapter 20Chapter 20Air PollutionAir Pollution
Overview of Chapter 20Overview of Chapter 20 Atmosphere as a ResourceAtmosphere as a Resource Types and Sources of Air PollutionTypes and Sources of Air Pollution Effects of Air PollutionEffects of Air Pollution Controlling Air Pollution in the USControlling Air Pollution in the US Ozone Depletion in the StratosphereOzone Depletion in the Stratosphere Acid DepositionAcid Deposition Air Pollution Around the WorldAir Pollution Around the World Indoor Air PollutionIndoor Air Pollution
Atmosphere as a ResourceAtmosphere as a Resource
Atmospheric CompositionAtmospheric Composition 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%
Ecosystem servicesEcosystem services Blocks UV radiationBlocks UV radiation Moderates the climateModerates the climate Redistributes water in the hydrologic Redistributes water in the hydrologic
cycle cycle
Air Pollution - TerminologyAir Pollution - Terminology
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
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, or with sunlight with other air pollutants, or with sunlight
Major Air PollutantsMajor Air Pollutants
Major Classes of Air PollutantsMajor Classes of Air Pollutants Particulate MaterialParticulate Material Nitrogen OxidesNitrogen Oxides Sulfur OxidesSulfur Oxides Carbon OxidesCarbon Oxides HydrocarbonsHydrocarbons OzoneOzone
Particulate MaterialParticulate Material 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 DangerousDangerous
May contain materials with toxic/carcinogenic May contain materials with toxic/carcinogenic effectseffects
Small particles can become lodged in lungsSmall particles can become lodged in lungs
Nitrogen and Sulfur OxidesNitrogen and Sulfur Oxides Nitrogen OxidesNitrogen Oxides
Gases produced by the chemical interactions Gases produced by the chemical interactions between atmospheric nitrogen and oxygen at between atmospheric nitrogen and oxygen at high temperaturehigh temperature
Greenhouse gases that cause difficulty Greenhouse gases that cause difficulty breathingbreathing
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 Carbon Oxides and HydrocarbonsHydrocarbons Carbon OxidesCarbon Oxides Gases carbon monoxide (CO) and carbon Gases carbon monoxide (CO) and carbon
dioxide (COdioxide (CO22) ) Greenhouse gasesGreenhouse gases
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 and Some are related to photochemical smog and greenhouse gasesgreenhouse gases
OzoneOzone Tropospheric OzoneTropospheric Ozone
Man- made pollutant in the lower atmosphereMan- made pollutant in the lower atmosphere Secondary air pollutantSecondary air pollutant Component of photochemical smogComponent of photochemical smog
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 destroy Man-made pollutants (ex: CFCs) can destroy
itit
Sources of Outdoor Air PollutionSources of Outdoor Air Pollution
Two main Two main sourcessources TransportationTransportation IndustryIndustry
Intentional Intentional forest fires is forest fires is also highalso high
Urban Air PollutionUrban Air Pollution
Photochemical Smog (ex: Los Photochemical Smog (ex: Los Angeles below)Angeles below) Brownish-orange haze formed by Brownish-orange haze formed by
chemical reactions involving sunlight, chemical reactions involving sunlight, nitrogen oxide, and hydrocarbons nitrogen oxide, and hydrocarbons
Formation of Photochemical Formation of Photochemical SmogSmog
Sources of Smog in Los AngelesSources of Smog in Los Angeles
Effects of Air PollutionEffects of Air Pollution
Low level exposureLow level exposure Irritates eyesIrritates eyes Causes inflammation of respiratory tractCauses inflammation of respiratory tract
Can develop into chronic respiratory Can develop into chronic respiratory diseasesdiseases
Children and Air PollutionChildren and Air Pollution 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
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
Without Without Electrostatic Electrostatic precipitatorprecipitator
With Electrostatic With Electrostatic precipitatorprecipitator
Controlling Air Pollution Controlling Air Pollution Smokestacks with Smokestacks with
electrostatic electrostatic precipitator (right)precipitator (right)
Controlling Air PollutionControlling Air Pollution
Smokestacks with Smokestacks with scrubbers (right)scrubbers (right)
Particulate material Particulate material can also be controlled can also be controlled by proper excavating by proper excavating techniquestechniques
Controlling Air PollutionControlling Air Pollution Gasoline vapors are a major source of VOC’s Gasoline vapors are a major source of VOC’s
(volatile organic compounds), which are (volatile organic compounds), which are extremely harmful!extremely harmful!
Phase I Vapor Recovery System for gasoline Phase I Vapor Recovery System for gasoline involves collecting unburned vapors from involves collecting unburned vapors from underground tanks at gas stations!underground tanks at gas stations!
The Clean Air ActThe Clean Air Act Authorizes EPA to set limits on amount of Authorizes EPA to set limits on amount of
specific air pollutants permittedspecific air pollutants permitted Focuses on 6 pollutants:Focuses on 6 pollutants:
lead, particulate matter, sulfur dioxide, lead, particulate matter, sulfur dioxide, carbon monoxide, nitrogen oxides, and ozonecarbon monoxide, nitrogen oxides, and ozone
Act has led to decreasesAct has led to decreases
The Clean Air ActThe Clean Air Act
Urban Air QualityUrban Air Quality
Other Ways to Improve Air Other Ways to Improve Air QualityQuality
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
Require federal emission standards for Require federal emission standards for all passenger vehiclesall passenger vehicles Including SUVs, trucks and minivansIncluding SUVs, trucks and minivans
Require emission testing for all vehiclesRequire emission testing for all vehicles Including dieselIncluding diesel
Ozone Depletion in Ozone Depletion in StratosphereStratosphere Ozone Protects earth from UV radiationOzone Protects earth from UV radiation
Stratospheric Ozone:Ozone (O3) forms a layer in the stratosphere,
measured in Dobson Units (typically 260 DU near the equator, higher toward the poles)
Ozone is created when UV radiation strikes molecules of Oxygen (O2) in the stratosphere, and splits (dissociates) them into free O atoms, which then quickly combine to form ozone.
1. O2 + UV -> O + O
2. O + O2 -> O3
Stratospheric Ozone:Ozone can then be destroyed & reformed
by the same UV radiation, in a natural cycle as follows:
3. O3 + UV -> O2 + O
4. O + O2 -> O3 as above Ozone levels peak at about 25 KM above
Earth’s surface. Stratospheric Ozone – absorbs 99% of
UV if left at “natural” levels
Three Categories of UV Radiation:
UV-C UV-B UV-A
Size of Wavelength:
200-280 280-320 320-400
Absorption:Fully absorbed
by O2 & O3Most is absorbed
by O3Mostly reaches
surface
Results Associated
with Exposure:
Serious cell mutation, cancer
Skin cancer & cataracts,
phytoplankton kills
Produces Vitamin D
with background
exposure levels
Ozone Depletion in Ozone Depletion in StratosphereStratosphereOzone thinning/holeOzone thinning/hole
First identified in 1985 over First identified in 1985 over AntarcticaAntarctica
Caused by human-Caused by human-produced produced bromine bromine and and chlorinechlorine containing containing chemicals. (Halogens)chemicals. (Halogens)
Ex: CFCsEx: CFCs propellants used for propellants used for
aerosol cans (no longer in aerosol cans (no longer in use)use)
coolants in refrigeration coolants in refrigeration (Freon)(Freon)
foam (Styrofoam) foam (Styrofoam) blowing agents in blowing agents in
insulationinsulation solventssolvents
How does Chlorine (CFC) destroy Ozone?Chemical reaction creates a catalyst!1.CCl3F + UV Cl + CCl2F
2.Cl + O3 ClO + O2
3.ClO + O Cl + O2
Ozone Depletion in Ozone Depletion in StratosphereStratosphere Hole over Antarctica requires Hole over Antarctica requires three three
conditionsconditions:: The development of the The development of the circumpolar vortexcircumpolar vortex
- a mass of frigid air that circulates around - a mass of frigid air that circulates around the southern polar region the southern polar region
The formation of The formation of polar stratospheric polar stratospheric cloudsclouds – masses of ice crystals onto which Cl – masses of ice crystals onto which Cl and Br can settle. This enables Cl and Br to and Br can settle. This enables Cl and Br to destroy ozonedestroy ozone
Sunlight just returning to polar region (occurs Sunlight just returning to polar region (occurs in spring in the S. hemisphere (Sept. – Oct.) in spring in the S. hemisphere (Sept. – Oct.) which triggers the release of the Cl and Br which triggers the release of the Cl and Br from the polar stratospheric cloudsfrom the polar stratospheric clouds
Effects of Ozone DepletionEffects of Ozone Depletion
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
May disrupt May disrupt ecosystemsecosystems
May damage crops May damage crops and forestsand forests
Recovery of Ozone LayerRecovery of Ozone Layer Montreal Protocol (1987)Montreal Protocol (1987)
Reduction of CFCsReduction of CFCs Started using HCFCs (greenhouse gas)Started using HCFCs (greenhouse gas)
Phase out of all ozone destroying Phase out of all ozone destroying chemicals is underway globallychemicals is underway globally
Satellite pictures in 2000 indicated that Satellite pictures in 2000 indicated that ozone layer was recoveringozone layer was recovering
Full recovery will not occur until 2050Full recovery will not occur until 2050
Acid DepositionAcid Deposition 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 the surface as either dry or wet deposition deposition
pH scalepH scale
How Acid Deposition DevelopsHow Acid Deposition Develops
Effects of Acid DepositionEffects of Acid Deposition
Declining Declining Aquatic Animal Aquatic Animal PopulationsPopulations
Thin-shelled Thin-shelled eggs prevent eggs prevent bird bird reproductionreproduction Calcium is Calcium is
unavailable in unavailable in acidic soilacidic soil
Forest declineForest decline
Acid Deposition and Forest Acid Deposition and Forest DeclineDecline
Air Pollution Around the WorldAir Pollution Around the World Air quality is deteriorating rapidly in Air quality is deteriorating rapidly in
developing countries developing countries Developing countries have older carsDeveloping countries have older cars
Shenyang, ChinaShenyang, China Residents only see sunlight a few weeks each Residents only see sunlight a few weeks each
yearyear 5 worst cities in world5 worst cities in world
Beijing, China; Beijing, China; Mexico City, Mexico; Mexico City, Mexico; Shanghai, China; Shanghai, China; Tehran, Iran;Tehran, Iran; Calcutta, India Calcutta, India
Case-In-Point Air Pollution in Case-In-Point Air Pollution in Beijing and Mexico CityBeijing and Mexico City
Beijing (left)Beijing (left) Mexico City (above)Mexico City (above)
Global Distillation EffectGlobal Distillation Effect
Long Distance Transport of Air Long Distance Transport of Air PollutantsPollutants
Indoor Air PollutionIndoor Air Pollution
Pollutants can Pollutants can be 5-100X be 5-100X greater than greater than outdoorsoutdoors
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