chapter 17 and 18 air 2015 i used this...

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Chapter 17Chapter 17Chapter 17Chapter 17

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� Weather – the state of the atmosphere in one area at one time.

◦ What is the weather today here?

� Climate - the long term prevailing weather at a

� particular place◦ What is the climate for here?

� Two places can have the same weather on the same day

◦ But they can have VERYVERYVERYVERY different climates

� Weather: Seattle and Phoenix might both have rain today

� Climate : Seattle is wet and cool, Phoenix is dry and hot

**It depends on their proximity top the equator.

Mark Twain said “Climate is what we expect; weather is what we get””””

• 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

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� TroposphereTroposphereTroposphereTroposphere = bottommost layer

◦ Air for breathing, weather

� StratosphereStratosphereStratosphereStratosphere = 11-50 km (7-31 mi) above sea level

◦ Drier and less dense, with little vertical mixing

◦ Colder in its lower regions

◦ Contains UV radiation-blocking ozone,

The two highest levels of The two highest levels of The two highest levels of The two highest levels of

the atmospherethe atmospherethe atmospherethe atmosphere

• MesosphereMesosphereMesosphereMesosphere = 50-80 km (31-56 mi) above sea level

- Extremely low air pressure

- Temperatures decrease with altitude

• ThermosphereThermosphereThermosphereThermosphere = atmosphere’s top layer

- Extends upward to 500 m (300 mi)

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� 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

LATITUDE

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.

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ATMOSPHERIC

CIRCULATIONThree basic rules:

1. Cold air sinks – but pressure

is 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!

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

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Hadley cells = near the equator,

surface air warms, rises, and

expands

Releases moisture and heavy

rainfall near the equator

Ferrel cells and polar cells = lift air

Creates precipitation at 60

degrees latitude north and

south

Causes air to descend at 30

degrees latitude

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•Prevailing winds – winds that blow predominantly in one direction

most of the year.

• From what direction does our prevailing wind come from?

(They are deflected to the right in the Northern Hemisphere)

•Trade Winds – the prevailing winds between 30°and equator.

OCEAN CIRCULATION PATTERNS

•Water holds a lot of heat

(think how much heat it

takes to boil water!)

• Ocean currents are caused by

winds and the movement of the earth

•The ocean currents move heat

around the globe.

• In the summer where would you rather swim?

Off California coast in LA or off the South Carolina coast

• Colder water flows south from Alaska, warm water flows

north from the Caribbean

Video

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EL NINO VS LA NINA

•Some ocean currents change the way they flow:

• El Nino-

• Pacific Ocean water near

Americas warms – leads to

increased clouds and rainfall

in SW US

• La Nina

• Opposite of El Nino, cooler

waters in Pacific near Americas,

droughts in the SW US

• Pacific Decadal Oscillation

• Similar to El Nino but the

switching occurs every

20 – 30 years

SUN’S IMPACT

•Solar Cycle – 11 year cycle of the sun.

• At the maximum – the sun emits UV radiation

• This can warm the lower atmosphere and Earth.

• On earth the Northern Lights can be seen as far south as Mexico on occasion.

• Increased radiation from the sun can cause warming of the atmosphere

Seasons – Why do we have them?

All due to the tilt of the earth – 23.5°relative to the plane of its orbit. (Angle of the sun’s rays striking the Earth)

http://www.nasa.gov/mov/143924main_AmazChangeSun_QT%20big%20progre.mov

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Temperature Inversion:

• 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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� Air Pollution Air Pollution Air Pollution Air Pollution – Harmful substances built up in the air to an unhealthy level◦ Pollutants can be from human activity – industry soot

◦ Pollutants can be natural – volcanic ash, pollen, dust, spores

� Primary Pollutant Primary Pollutant Primary Pollutant Primary Pollutant – put into air directly by human activity◦ Soot from smoke

and fires

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� Secondary PollutantSecondary PollutantSecondary PollutantSecondary Pollutant – form when primary pollutants react with each other or natural substances◦ 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

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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)

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

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� Industrial plants burn fossil fuels◦ Burning releases – Sulfur Dioxide and Nitrous Oxide� Power Plants emit 2/3 of ALL SO2 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

� Clean Air Act Requires Industries to use:◦ ScrubberScrubberScrubberScrubber: cleans emissions of plants by washing it and filtering it◦ Electrostatic PrecipitatorElectrostatic PrecipitatorElectrostatic PrecipitatorElectrostatic Precipitator: uses static charges to get particulates to clump together and collect, clean gas continues on. (used in cement factories/coal burning plants)

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Industrial Air Pollution

Plant Scherer

Georgia

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SmogSmogSmogSmog: Air pollution that hangs over urban areas and reduces visibility

Industrial (gray air) Industrial (gray air) Industrial (gray air) Industrial (gray air) smogsmogsmogsmog = industries burn coal or oil

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Photochemical (brown air) smog

• Produced by a series of reactions

- Hot, sunny cities surrounded by mountains

- Light-driven reactions of primary pollutants and normal atmospheric compounds

- Morning traffic exhaust releases pollutants

- Irritates eyes, noses, and throats

- Vehicle inspection programs in the U.S. have decreased smog

Secondary Pollution

Nitrogen Oxide is associated with

Photochemical Smog

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• 17.16

Industrial smog Photochemical smog

Sulfur 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 are non flammable, non poisonous,

and non reactive at the Earth’s surface

• 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

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•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

• Scientists estimate that a single chlorine atom can break down

100,000 ozone molecules.

OZONE HOLE

• 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

(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.

VIDEO ON OZONE

DEPLETION

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WHY CARE ABOUT OZONE?• Ever have a bad sunburn?

• UV radiation can damage organisms DNA

• Can lead to skin and other cancers

• Notable impact to amphibian eggs (death/mutations)

• Phytoplankton can be killed by UV

• Phytoplankton is the producer for most ocean food chains

• Phytoplankton loss would also effect atmospheric CO2 levels

• Montreal Protocol

• 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

� Many air pollution effects are short term◦ Can be reversed when exposure is decreased

� Short term effects:

� NauseaNauseaNauseaNausea

� HeadachesHeadachesHeadachesHeadaches

� Eye IrritationsEye IrritationsEye IrritationsEye Irritations

� Coughing Coughing Coughing Coughing

� Upper respiratory infections Upper respiratory infections Upper respiratory infections Upper respiratory infections

(bronchitis, pneumonia)(bronchitis, pneumonia)(bronchitis, pneumonia)(bronchitis, pneumonia)

� Will make asthma worseWill make asthma worseWill make asthma worseWill make asthma worse

• Greatest effect on children ages 5 and lower

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� Many air pollution effects are long term◦ CannotCannotCannotCannot be reversed when exposure is decreased

� Long term effects:

� 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, paints can pollute indoor air

◦ Sick Building SyndromeSick Building SyndromeSick Building SyndromeSick Building Syndrome –buildings with very poor air quality

� Found in hot climates where buildings are sealed to keep out heat.

� Fungi can grow and there is no release of the toxic chemicals released from carpet, paint etc.

� All builds up to drastically reduce indoor air quality

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� 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

� 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

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� 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. Noise levels greater than this can cause permanent damage.

• Protection from noise pollution:• Mufflers on autos and yard equipment

• MP3 players in Europe can only go up to 100 dB

• Ear protection

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� 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 wasted, only goes to spaceUpward directed light is wasted, only goes to spaceUpward directed light is wasted, only goes to spaceUpward directed light is wasted, only goes to space

� Acid precipitationAcid precipitationAcid precipitationAcid precipitation is rain with a high concentration of acids

� pH measures acid acid acid acid concentrationconcentrationconcentrationconcentration◦ Low numbers are more acidic. Below 7 is acidicBelow 7 is acidicBelow 7 is acidicBelow 7 is acidic. The closer to zero – the more acidic.◦ Each change in pH (1 to 2) indicates a ten times difference in acidity

� Normal rainNormal rainNormal rainNormal rain has a pH of 5.65.65.65.6, acid precipitationacid precipitationacid precipitationacid precipitationstarts at 5.05.05.05.0

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� AcidificationAcidificationAcidificationAcidification –Increase of acid in soils or lakes

� Acid chemically reacts with soil minerals◦ Some nutrients are Some nutrients are Some nutrients are Some nutrients are dissolved and washed dissolved and washed dissolved and washed dissolved and washed away from where plants away from where plants away from where plants away from where plants can use themcan use themcan use themcan use them

◦ Metals like aluminum Metals like aluminum Metals like aluminum Metals like aluminum are released into the soil are released into the soil are released into the soil are released into the soil and possibly absorbedand possibly absorbedand possibly absorbedand possibly absorbed

� High enough levels of High enough levels of High enough levels of High enough levels of these metals can be these metals can be these metals can be these metals can be toxictoxictoxictoxic

How Does Acid Precipitation Affect How Does Acid Precipitation Affect How Does Acid Precipitation Affect How Does Acid Precipitation Affect Soils and PlantsSoils and PlantsSoils and PlantsSoils and Plants

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� Aquatic animals live within a very narrow pH range ◦ Acid rain changes pH level of lake and kills fishAcid rain changes pH level of lake and kills fishAcid rain changes pH level of lake and kills fishAcid rain changes pH level of lake and kills fish

� Acid precipitation leaches metals like aluminum from soil near lake/river ◦ Metals accumulate in fish bodies until reach toxic levelsMetals accumulate in fish bodies until reach toxic levelsMetals accumulate in fish bodies until reach toxic levelsMetals accumulate in fish bodies until reach toxic levels

� Acid ShockAcid ShockAcid ShockAcid ShockIn the spring when acid

snow melt and flows into

rivers and lakes the sharp

change in pH kills massive

amounts of aquatic creatures

46464646

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� Kills fish and other aquatic organisms.

� “Acid shock” in the spring may kill many at one time.

� Humans depend on plants, animals, and seafood items for food ◦ If plants, animals, fish die off we If plants, animals, fish die off we If plants, animals, fish die off we If plants, animals, fish die off we lose food sources.lose food sources.lose food sources.lose food sources.

� Toxic metals taken in by Toxic metals taken in by Toxic metals taken in by Toxic metals taken in by plants, animals, fish also plants, animals, fish also plants, animals, fish also plants, animals, fish also accumulate in us and can reach accumulate in us and can reach accumulate in us and can reach accumulate in us and can reach toxic levelstoxic levelstoxic levelstoxic levels

� Aesthetics – Statues and Statues and Statues and Statues and buildings are deteriorating due buildings are deteriorating due buildings are deteriorating due buildings are deteriorating due to acid rainto acid rainto acid rainto acid rain

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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

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What is climate change?• Global climate change = describes trends and variations in Earth’s climate

- Temperature, precipitation, storm frequency

• Global warming = an increase in Earth’s average temperature

- Earth’s climate has varied naturally through time

- The rapid climatic changes taking place now are due to human activity: fossil fuels, combustion, and deforestation

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GREENHOUSE EFFECT

• The earth is like a greenhouse

• The atmosphere acts like the glass – which lets the sun’s rays pass through.

• The earth absorbs this as heat energy and keeps it in, only letting a little heat out

• The gases in the atmosphere absorb the radiation keeping it from escaping out to space

• This absorption of radiation by gases is called the greenhouse effect

GREENHOUSE GASES

• Water Vapor, CO2, CFCs, Methane and NOx all absorb radiation

• Water vapor and CO2 are the primary greenhouse gases

• Since 1958 (in Hawaii) CO2 levels have been measured – reflective of the entire earth (the gases have traveled across the entire Pacific Ocean)

• Levels are higher in the winter: fewer leaves on the trees (dying

grasses and leaves release carbon)

• General increase because of burning fossil fuels(not just in winter)

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GLOBAL WARMING

• Where does all the CO2 come from?

• Power plants and cars that burn fossil fuels and deforestation

• Why be concerned?

• CO2 is a greenhouse gas

• Scientists believe the increase will warm earth more than normal

• Direct correlation between CO2 levels and global warming


Aerosols may exert a cooling effect

• Aerosols = microscopic droplets and particles that have either a warming or cooling effect

• Soot, or black carbon aerosols, cause warming by absorbing solar energy

- But, most tropospheric aerosols cool the atmosphere by reflecting the Sun’s rays

• Sulfate aerosols produced by fossil fuel combustion may slow global warming, at least in the short term

- Volcanic eruptions reduce sunlight reaching the earth and cool the Earth

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Albedo Effect• Ability of a surface to reflect light

• Ice, especially with snow on top of it,

has a high albedo

• Most sunlight hitting the surface

bounces back towards space

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WHAT HAPPENS IF THE EARTH WARMS?

• Melting Ice and Rising Sea Levels

• Coastal areas flooded

• Nearly 3 billion people live

within 100 km of a coast

• Excess sea water can change

freshwater aquifers near coasts

• Changing Weather Patterns

• Warming the oceans could change

currents that influence weather today

• Human Health Problems

• Deaths due to heat waves

• Longer growing seasons, more pollen, more asthma

• Warmer weather allow mosquitoes and other disease carrying organisms to live longer

• Agriculture

• Heat leads to droughts,

severe impact to crops

• May change where plants

and animals live

• Kyoto Protocol

• Nations met and laid out

timelines for reducing CO2

emissions

• Decrease emissions by 5%

from 1990 levels by 2012.

• Reducing CO2 is difficult for

developing countries

• Need industry using

cheap fossil fuel to

improve economies

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Results from three simulations

• Figure (a) shows natural climate factors only

- Volcanoes

• Figure (b) shows only human factors

- Emissions of greenhouse gases

• Figure (c) shows both factors


Current and future trends and impacts

Evidence that climate conditions have changed since industrialization has increased

• Intergovernmental Panel on Climate Change (IPCC)

- An international panel of scientists and government officials established in 1988

- Has presented a series of reports on the synthesis of scientific information concerning climate change

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Temperature increases will continue

• The IPCC report concludes that average surface temperatures on earth have been rising since 1906, with most of the increase occurring in the last few decades


U.S. Global Change Research Program

(1990)

• Predicted:

- Temperature increases

- Worse droughts and flooding

- Decreased crop yields and water shortages

- Health problems and mortality

- Altered forest ecosystems

- Lost coastal areas

- Undermined Alaskan buildings and roads

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The debate over climate change is over

• Most Americans accept that fossil fuel consumption is changing the planet

• An Inconvenient Truth helped turn the tide

- 84% of people surveyed thought that humans contribute to global warming

- Many corporations offer support for greenhouse gas reductions

Inconvenient Truth Video


Electricity generation

• Largest source of U.S. CO2 emissions

• Two ways to reduce fossil fuel use: conservation and efficiency

- Arise from technology and individual choices

- Replacing worn-down appliances with newer models, lifestyle choices

- Use fewer greenhouse-gas-producing products

A coal-fired,

electricity-

generating power

plant

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Sources of electricity

• We can change the energy we use

- Natural gas

- Carbon-capture = technologies or approaches that remove CO2 from power plant emissions

- Carbon sequestration (storage) = storing carbon somewhere (underground?) where it will not seep out

- Use technologies and energy sources without using fossil fuels (nuclear, hydroelectric, solar power, etc.)


Transportation

• 2nd largest U.S. greenhouse gas

• The typical automobile is highly inefficient

• Ways to help:

- Technology: make vehicles more fuel-efficient, hybrid cars

- Drive less and use public transportation

- Public transportation is the most effective way to conserve energy, reduce pollution

- Live nearer your workplace, so you can bike or walk

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Conventional cars are inefficient


You can reduce your own footprint

• Our carbon footprint expresses the amount of carbon we are responsible for emitting

- You may apply many strategies such as deciding where to live, how to get to work, and what appliances to buy to decrease your footprint

• Global climate change may be the biggest challenge facing us and our children

- Taking immediate action is the most important thing we can do

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Ozone depletion

Climate Change

chapter 17 and 18 air 2015 i used this...

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