chapter 17 and 18 air 2016 - weebly · 3/14/2016 5 • volcanoes • lightning • forest fires •...
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Chapter 17Chapter 17Chapter 17Chapter 17
Video
• Layer of gases surrounding the planet Earth and retained by the Earth's gravity.
• It contains roughly 78% nitrogen, 21% oxygen, and 1% other.
Inactive gases1%
• Its four layers differ in temperature, density and composition
• Human activity is changing the amounts of some gases
Earth's atmosphere can be divided (called atmospheric stratification) into five main layers. From highest to lowest, these layers are:1.1.1.1. Exosphere: Exosphere: Exosphere: Exosphere: atmosphere merges
with outerspace (>440 miles)2.2.2.2. ThermosphereThermosphereThermosphereThermosphere: International
Space stationg orbits, aurora borealis (50 to 440 miles)
3.3.3.3. MesosphereMesosphereMesosphereMesosphere: coldest, meteors burn here (31 to 50 miles)
4.4.4.4. StratosphereStratosphereStratosphereStratosphere: ozone layer (7 to 31 miles)
5.5.5.5. TroposphereTroposphereTroposphereTroposphere: weather(0 to 7 miles)
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Mark Twain
◦ What is the weather today here?� Weather is a short-term atmospheric condition in an area. They include:
• TemperatureTemperatureTemperatureTemperature
• HumidityHumidityHumidityHumidity
• PrecipitationPrecipitationPrecipitationPrecipitation
• Cloud coverCloud coverCloud coverCloud cover
� Climate is a region’s general pattern of atmospheric condition over a long period of time (at least 30 yearsat least 30 yearsat least 30 yearsat least 30 years). The two major factors contributing to a region’s climate:
� average temperature
� average precipitation
What is the climate for here?
“Climate is what we expect; weather is what
we get”
� Climate is determined by:
◦ Atmospheric Circulation Atmospheric Circulation Atmospheric Circulation Atmospheric Circulation
PatternsPatternsPatternsPatterns
◦ Oceanic Circulation PatternsOceanic Circulation PatternsOceanic Circulation PatternsOceanic Circulation Patterns
◦ Local geographyLocal geographyLocal geographyLocal geography
◦ Solar activitySolar activitySolar activitySolar activity
◦ Volcanic ActivityVolcanic ActivityVolcanic ActivityVolcanic Activity
� Which is most important?� Latitude
(How far above/below you are from the equator)
Video
REASON FOR SEASONS
Latitude is the distance north or south of the equator. Measured in degrees.
• Equator is 0 degrees, the poles are 90 degrees
• Low Latitudes – get the strongest, most concentrated sunlight.• Night and Day are 12 hours, all year round
• High temps all year round
• High Latitudes – sunlight is spread over a greater area, weaker, less energy
• Daylight hours vary
• At the poles the sun sets for only a few hours during the summer
• Dark almost all day during winter
• Average annual temperatures lower than at equator.
Three basic rules:
1. Cold air sinks – but pressureis stronger at lower levels so cold air
gets compressed and thus warms.
2. Warm Air Rises – lower
pressure lets it expand and it cools
down
3. Warm Air holds more water vapor
than cold air – so as it rises the water
vapor cools and condenses
How do we get wind?
1. Sun heats the earth surface.2. Hot Air Rises
3.Cold Air replaces it………wind!
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Ferrel cells and polar cells = lift air
Creates precipitation at 60 degrees
latitude north and south
Causes air to descend at 30 degrees
latitude
Hadley Cells are the low-latitude
overturning circulations that have air rising at the equator and air sinking at roughly
30°latitude. They are responsible for the
trade winds. A lot of rain.
CORIOLIS EFFECT
Coriolis effect = the north-south air currents of the convective cells appear to be deflected from a straight path
• Results in curving global wind patterns
GPS videoCurrent Animation
Because the Coriolis effect increases with an item’s increasing speed, it significantly deflects airflows and as a result the
wind.
In the Northern Hemisphere these winds spiral to the right and in the Southern Hemisphere they spiral to the left. This
usually creates the westerly winds moving from the subtropical areas to the poles.
Video
Planetary Winds
Global scale winds are winds that are
created in the different Global circulation
Cells.
• The polar easterlies blow from the Pole to
60
• The Prevailing Westerlies blow from 60 to
30
• Near the equator
• The Trade Winds blow from 30 to 0
OCEAN CIRCULATION PATTERNS
Video
The Gulf Stream is driven largely by wind, but as it branches into the North Atlantic Drift, it is largely thermohaline circulation driven.
Ocean currents• Currents also help mix ocean waters to distribute nutrients and dissolved oxygen
needed for aquatic organisms• Winds moving away from coastal regions result in upwelling of cold, nutrient-rich
bottom waters as surface water moves offshore. These nutrients support large
populations of phytoplankton, zooplankton, fish, and fish-eating sea birds.
• El Niño and La Niña are changes in climate patterns that can trigger mild to
extreme weather changes over at least ⅔ of the globe.
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El Niño Animation
ENSO
Simulation
• Surface water warms along the North and South American coasts, and upwelling
of nutrients is suppressed, which reduces primary productivity that results in sharp decline of fish population.
• Jet stream above North America is also distorted, changing weather patterns.
• leads to increased clouds and rainfall in SW US
• El Niño/Southern Oscillation (ENSO) results from a change in direction of
tropical winds. Trade winds blowing west are weakened or reversed.
La Nina• La Niña cools some coastal surface waters and brings back coastal
upwelling. This results in warmer, drier winters in the southeastern and
southwestern U.S., wetter winters in the Northwest.
• Typically a La Niña causes more destruction in the U.S. because there are
more Atlantic coast hurricanes and tornadoes.
• Similar to normal conditions, just enhanced.
RAIN SHADOW
•Rain Shadow•Dry area on the eastern side of mountains
•The smaller the mountains, the weaker the
rain shadow effect, and vice versa.
• Air circulation usually stops
pollution from accumulating to dangerous levels.
• Inversions trap pollution near the
Earth’s Surface
• Temperature usually decreases
with altitude
• But a warm layer above a cold
layer will trap pollution
• (Hot air rises, right? Hot smoke
rises, but if atmosphere is just as warm, the smoke stays put)
Temperature Inversion
Video
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• Volcanoes
• Lightning
• Forest fires
• Plants
Air pollution SourcesNatural Sources of Air Pollution
Anthropogenic Sources of Air Pollution
•On-road vehicles
•Power plants
•Industrial processes
•Waste disposal
� Air Pollution Air Pollution Air Pollution Air Pollution – chemicals, particulate matter, or microorganisms found
in the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings or to alter ecosystems
•Primary pollutants: polluting compounds coming directly out of smoke-stacks, exhaust pipes, or natural emission source
•Five types:•CO, CO2, SO2, NOx, and most suspended particulate matter
•Secondary pollutants:pollutants transformed in the presence of sunlight, water, oxygen or other compounds
•Examples: ozone, sulfate, and nitrate
What is the biggest source of primary pollutants?
Transportation
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◦ Ground Level OzoneGround Level OzoneGround Level OzoneGround Level Ozone – is formed when car emissions (primary) interact with oxygen and UV rays (both natural)
AKA: Tropospheric Ozone
Major factors are H2O and Sunlight
Pollutant Composition Source P/S Effects
Particulate matter
Various Industry P Respiratory
illness
Nitrogen oxides
NO2 Cars, industry,
fertilizer
P Irritate
respiratory
Sulfur oxides
SO2 Coal-fire
power plants
P Irritate
respiratory
Carbon oxides
CO, CO2 Cars,
industry
P Reduces
blood’s ability to carry O2
ozone O3 Photochemical S Irritate eyes,
respiratory
Major Air Pollutants
Particulate MatterParticulate Matter (PM)-is a complex mixture of extremely small particles and liquid droplets
Ex: organic chemicals, metals, and soil or dust particles.
• EPA is concerned about particles that are 10 micrometers (PM10) or lower.
• Go into your lungs and bloodstream.
• Lead-(Pb) is a metal found naturally in the environment as well as in manufactured products.
• Major sources are from fuels in on-road motor vehicles (such as cars and trucks) and industrial sources.
• Also in paint, dust and soil• Neurological effects in children and
cardiovascular effects
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� Industrial plants burn fossil fuels◦ Burning releases – Sulfur Dioxide and Nitrous Oxide
� Power Plants emit 2/3 of ALL SOSOSOSO2222 and 1/3 of ALL NO
� VOCs VOCs VOCs VOCs (Volatile Organic Compounds) (Volatile Organic Compounds) (Volatile Organic Compounds) (Volatile Organic Compounds) - chemical
compounds that form toxic fumes
◦ Given off by – Oil refineries, Dry Cleaners, Chemical plants
Industrial Air Pollution
Plant Scherer
Georgia
SmogSmogSmogSmog: forms when sunlight, nitrogen oxides (Nox), and volatile organic compounds (VOCs) are present.
Industrial (gray air) Industrial (gray air) Industrial (gray air) Industrial (gray air) smogsmogsmogsmog = industries burn coal or oil
Video Clip (smog eating building)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Photochemical smog (brown air)
Secondary Pollution
• A secondary pollution• Photochemical smog is still an environmental problem in the United States.
• Sunlight + Nitrogen Oxides + VOCs produced Ozone.
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Photochemical Smog
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• 17.16
Industrial smog Photochemical smogSulfur dioxides (SO2) Nitrogen Oxide (NO)
OZONE LAYER
•Ozone is the chemical compound O3
• Large concentration is found in the stratosphere
• Ozone Layer absorbs most UV radiation
coming from the sun
• UV radiation can damage organisms
cells
• UV-B- most absorbed by ozone
•Chemicals Can Destroy Ozone
• CFCs – chlorofluorocarbons
• CFCs used as propellants in spray cans and coolants in fridges/air conditioners
• It takes 10 -20 years for CFCs to reach the stratosphere from the Earth's surface
•CFCs are broken apart in the stratosphere
• High energy of the UV radiation breaks it down
• The single chlorine from CFC can react with O3 and changes it, depleting the O3
OZONE LAYER
• Scientists estimate that a single chlorine atom can break down 100,000 ozone molecules.
Ozone depletion
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• First noticed in 1970 from satellite photos over the South Pole
• What Causes it?
• During the cold polar winters, dry stratospheric air over the pole is isolated.
• Air becomes so cold that it condenses and forms clouds
VIDEO ON OZONE DEPLETION
OZONE LAYER
(Polar Stratospheric clouds: high-altitude clouds made of water and nitric acid at - 80°C)
• Chlorine from CFCs builds up
on the surface of the clouds
• When the pole begins to
warm the chlorine goes back
to depleting ozone.
OZONE LAYER
The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone depletion.• Many nations banned the use of CFCs in 1992
(US stopped production by 2000)• CFCs still a problem….Why?• CFCs molecules remain in the stratosphere for 60
– 120 years
Negative affects of ozone depletion:• Ever have a bad sunburn?• UV radiation can damage organisms DNA
• Phytoplankton can be killed by UV
Can be reversed when exposure is decreased• Nausea• Headaches• Eye Irritations• Coughing • Upper respiratory infections
(bronchitis, pneumonia)• Greatest effect on children ages 5
and lower
AcuteAcuteAcuteAcute----short term effectsshort term effectsshort term effectsshort term effects Chronic- long term effects
Cannot be reversed when exposure is decreased• Emphysema• Lung Cancer• Heart Disease• May damage lungs of young
children
◦ Air inside a building is sometimes WORSE than air outside
� Chemicals used in making carpets, furniture, copy machines, and paints can pollute indoor air
◦ Sick Building SyndromeSick Building SyndromeSick Building SyndromeSick Building Syndrome – buildings with very poor air quality
� Buildings that are sealed have very poor air quality
Preventing bad indoor air pollutionPreventing bad indoor air pollutionPreventing bad indoor air pollutionPreventing bad indoor air pollution• Remove the source of the pollution• Remove carpet, new paint• Good ventilation to mix the indoor air with outdoor air• Decreases the amount of pollution per unit of air
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Radon GasRadon GasRadon GasRadon Gas◦ Colorless, odorless gas – 2nd leading cause of
lung cancer
◦ Occurs after uranium decays, found naturally in the earth, can seep into houses.
� Have a radon detector in the house
AsbestosAsbestosAsbestosAsbestos• A fire resistant substance used in
building materials before the 1970s.
• When inhaled the fibers can cut and scar the lungs leading to breathing difficulties and heart failure.
• Billions of dollars have been spent in asbestos removal
• Defined as unwanted soundunwanted soundunwanted soundunwanted sound• Noise kills nerve cells in the ear• 12% of teens have permanent
hearing loss• Intensity of sound is measured in
decibelsdecibelsdecibelsdecibels• 120 dB 120 dB 120 dB 120 dB is at the threshold of pain.
� Not a direct hazard to human health
◦ Does impact environment and enjoyment of night sky.
� Bigger threat is wasted energywasted energywasted energywasted energy
◦ Upward directed light is Upward directed light is Upward directed light is Upward directed light is wasted, only goes to spacewasted, only goes to spacewasted, only goes to spacewasted, only goes to space
Acid Deposition•Acid deposition: nitrogen oxides and sulfur oxides released into the atmosphere combine with atmospheric oxygen and water.
•These become the secondary pollutants nitric acid and sulfuric acid.
•These secondary pollutants further break down into nitrate and sulfate, which create the acid in acid deposition.
Effects of Acid Deposition•Lowers the pH of lake water
•Acid Shock-mass killing of aquatic organisms
•Decreases species diversity in aquatic ecosystems•Mobilizes metals (aluminum) found in soils and releases these into surface waters
•Metals accumulate in fish bodies until reach toxic levels
•Damages statues, monuments, and buildings and other structures
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Acid rain may dissolve thecalcium carbonate found inconcrete , marble, and limestone.
� Acid rain is hard to regulate because the pollution that causes it blows with the wind.
� One country’s pollution could float into another country causing acid rain there.
� Countries are signing Air Quality agreementsAir Quality agreementsAir Quality agreementsAir Quality agreements with each other to help reduce polluting emissions
Ways to Prevent Air Pollution
•Catalytic converters on cars•Scrubbers on smoke stacks- : cleans emissions of plants by washing it and filtering it•Baghouse filters
•Electrostatic precipitators -uses static charges to get particulates to clump together and collect, clean gas continues on. (used in cement factories/coal burning plants)
ScrubberScrubberScrubberScrubber
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Clean Air Act
The setting of maximum pollutant standards was coupled with directing the states to develop state implementation plans (SIP's) applicable to appropriate industrial sources in the state.
Federal law that regulates air emissions. This law authorizes EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and the environment.
Overseen by Environmental Protection Agency (EPA)
The EPA required the gradual elimination of lead in gasoline. To date lead pollution has been reduced by more than 90 % in US. California – Zero Emission Law – Is that possible? Battery operated vehicles are the only “true” ZEVs (zero emission
vehicles)