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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)