Lecture 13Fuel Cell Lectures

8/11/2019 Lecture 13Fuel Cell Lectures

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Chapter 14

Environmental Impact ofFuel Cell

Lecture Notes

Dr Sammia Shahid


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Fuel Cells Advantages

Green Design Reacts with oxygen and produces water vapor

Less hazardous materials

Greater Performance Capable of longer life without recharge

Recharge in less then a minute

Minimal performance decrease over time

Lifespan longer then batteries Advantage over current batteries


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Fuel Cells Disadvantages

Cost

Not proven

Risk of Hydrogen Supply of Hydrogen Gas

Expensive

Difficult to Distribute


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Life Cycle Assessment (LCA)

LCA is an important tool which we can use to

evaluate how a new energy technology (such as

fuel cells) affects energy use, energy efficiency,

emissions and other environmental

consequences.

To conduct a LCA thoroughly, we will need toquantify the most important global warming and air

pollution emissions.


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LCA consists of three primary stages:

1) Analyze the relevant energy and material inputs and outputs

associated with the change in energy technology along the entire

supply chain. The supply chain begins with raw materialextraction, continues to processing, then to production and end

use and finally to waste management.

2) Quantify the environmental impacts associated with these energy

and material changes.

3) Rate the proposed change in energy technology against other

scenarios.

Life Cycle Assessment as a Tool


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Supply Chain for Todays Conventional

gasoline Internal Combustion Engine

Energy is consumed (bottom arrows) and emissions are

produced (top arrows) during the primary processes

(represented as boxes) from petroleum fuel extraction to its use

on a vehicle.


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Using the methodology for LCA, we can build and analyze

a potential supply chain for fuel cell vehicles:

1) Research and develop an understanding of the supplychain from raw material production to end use.

2) Sketch a supply chain showing important processes and

primary mass and energy flows.

3) Identify the most energy intensive and most polluting

portions of the chain, that is bottleneck processes.

Life Cycle Assessment Applied to

Fuel Cells


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Supply Chain for Hydrogen Fuel

Cell Vehicle


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The Earths Climate System - Very complex!!


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Structure of the Atmosphere

Thermosphere

Mesosphere

Ozone Maximum

Stratosphere

Troposphere

Temperature


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What is the Greenhouse effect?

The greenhouse effect is the rise in temperature thatthe Earth experiences because certain gases in the

atmosphere trap heat from the Sunsrays.


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Have you seen a greenhouse

Most greenhouses

look like small

glasshouses.

Green houses are

used to grow plants,especially in the

winter.


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How do greenhouses work

Greenhouses work

by trapping heat

from the sun.

The glass panels of

the greenhouse let

in light but keepheat from escaping.


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This causes the greenhouse to heat up much like

the inside of a car parked in sunlight, and keeps

the plants warm enough to live in the winter.


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The Greenhouse Effect

The Earths

atmosphere is all

around us. It is the

air we breathe.

Greenhouse gases

in the atmosphere

behave much like

the glass panes in a

greenhouse.


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Sunshine enters the Earths

atmosphere passing through the

blanket of greenhouse gases.

As it reaches the Earthssurface, land,

water, and biosphere absorb the

sunlightsenergy! Once absorbed this

energy is sent back into the

atmosphere.


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Some of the energy

passes back into

space.

Much of it remains

trapped in the

atmosphere by the

greenhouse gases,

causing our world to

heat up.


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The greenhouse effect is

important.

Without the greenhouse effect, the Earthwould not be warm enough for humans to

live.

But if the greenhouse effect becomesstronger, it could make the Earth warmer

than usual.

Even a little warming

causes problems for

plants and animals.


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Greenhouse Effect

Without these gases, heat would escape

back into space and Earths average

temperature would be about 60 F colder.

Because of how they

warm our world, these

gases are referred toas greenhouse gases.


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What are these gases?

The greenhouse

gases are:

Water Vapour

Carbon dioxide

Nitrous Oxide

Methane

CFCs


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Water Vapour

There is more water in the atmosphere than carbon

dioxide so most of the greenhouse heating of the

Earthssurface is due to water vapour.

The water vapour content in the atmosphere isconstant which means it hasntchanged.


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Water Vapour

Water vapour is the biggest contributor to

the naturalgreenhouse effect

Human activities have little impact on the

level of water vapour.


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Carbon Dioxide

Our atmosphere contains many natural gases other

than ozone. One of these natural gases is carbon

dioxide.

Our atmosphere needs a

certain amount of this gas.

It is carbon dioxide that helpsto keep the Earth warm.


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Carbon Dioxide

This gas holds in just enough heat from

the sun to keep animals and plants alive.

If it held in more heat than it does theclimate on Earth would grow too hot for

some kinds of life.

If it held in less heat, Earths climatewould be too cold.


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Carbon Dioxide

Carbon Dioxide is probably the most importantof the greenhouse gases and is currently

responsible for 60 % of the enhanced

greenhouse effect

Enhanced

Human activities, not natural.

Global carbon dioxide emissions


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Carbon Dioxide

For the past 100years, the amount of

carbon dioxide in our

atmosphere seems to

have been increasing.

Why is this

happening?

What is it doing to the

Earthsatmosphere?


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Where do all the carbon dioxide gases

come from?

Carbon dioxide Human respiration.

Industrialization

Burning of fossil fuel to generate electricity

Burning of forest (lesser trees) CO2 is now 1/3 more than before Industrial

Revolution


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Carbon Dioxide

Burning fossil fuels release the carbon

dioxide stored millions of years ago.

We use fossil fuels to run vehicles (petrol,diesel, and kerosene), heat homes,

businesses, and power factories.


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The CO2Cycle

Sources: volcanism,

metamorphism, respiration,fossil fuel burning, deforestation

Sinks: photosynthesis, rock

weathering, carbonate

depsoition, ocean adsorption

Th CO C l E th Th t t


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Increased volcanism inputs huge quantities of CO2 into the

atmosphere = Tincreases

The CO2Cycle as Earths Thermostat

Tincrease causes increased chemical weathering and marine

carbonate deposition which lowers atmospheric CO2


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Feedback is not instantaneous! Perturbations in CO2cycle take on the order of 500,000 years to restore.

The CO2Cycle as Earths Thermostat


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Nitrous Oxide

Nitrous oxide makes up an extremely small

amount of the atmosphere It is less than

one-thousandth as abundant as carbon

dioxide.

However it is 200 to 300 times more

effective in trapping heat than carbon

dioxide.


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Nitrous Oxide

Nitrous Oxide has one of the longest atmospherelifetimes of the greenhouse gases, lasting for up

to 150 years.

Since the Industrial Revolution, the level of nitrous

oxide in the atmosphere has increased by 16%.


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Nitrous Oxide

The impact of

human activities

Burning fossil fuels

and wood

Widespread use of

fertilizersSewage treatment

plants


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Where do all nitrous oxide gases come

from?

Nitrous Oxide

Vehicle exhaust

Nitrogen based fertilisers


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Methane

The importance ofmethane in thegreenhouse effect isitswarming effect.

It occurs in lowerconcentrations thancarbon dioxide but itproduces 21 times asmuch warming ascarbon dioxide.


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Methane

Methane accounts for

20%of the enhanced

greenhouse effect.

It remains in the

atmosphere for 10-12

years. (Less than

other greenhouse

gases)


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Where do all the methane gases come

from?

Methane Produced by bacteria living in swampy areas.

Wet rice cultivation

Waste in landfills

Rearing of livestock When cows belch (burp)

Each molecule can trap 20 times as much

heat as a CO2molecule.


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Where do all the CFCs come

from?

CFCs (Chlorofluorocarbons)

Aerosol sprays

Making foam packaging

Coolants in fridge and air cons Cleaning solvents

Each CFC molecule can trap as much heat as

100 000 CO2molecule.

Can remain in the atmosphere for a long time(up to 20 000 years)


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Global Warming

What is it?

Earth has warmed by about 1 F over the

past 100 years. But why? And How?

Scientists are not exactly sure.

The earth could be getting warm on its

own.


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Electromagnetic Spectrum

incoming outgoing


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However

Many of the worlds leading climate

scientists think that things people do

are helping to make the Earth warmer.

Scientists are sure about the

greenhouse effect. They know that

greenhouse gases make the earthwarmer by trapping energy in the

atmosphere.


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Global Warming

The average global temperature has increased

by almost 1 F over the past century.

Scientists expect the average globaltemperature to increase an additional 2 to 6

F over the next hundred years.


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Global Warming

At the peak of the last ice age (18, 000 years ago)

the temperature was only 7 colder than it is today,

and glaciers covered much of North America.


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Global Warming

Even a small increase in temperature over a longtime can change the climate.

When the climate changes, there may be big

changes in the things that people depend on.


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Global Warming

These things include the

level of the oceans and the

places where we plant crops.They also include the air we

breathe and the water we

drink.


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Global Warming

Some changes may

be good.

Days and nights

would be morecomfortable and

people in the area

may be able to grow

different and bettercrops than they could

before.


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Global Warming

Changes in some places will not be good at all.

Human Health

Ecological Systems

(Plants and animals)Sea Level Rise

Crops and Food

Supply


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Human Health

Heat stress and other heat related healthproblems are caused directly by very warm

temperatures and high humidity.

Heat stressA variety of problems associated

with very warm temperatures and high

humidity eg. Heat exhaustion and heat stroke.


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Ecological Systems

Plants and animalsClimate change may alter the worlds habitats.

All living things are included in and rely on theseplaces.

Most past climate changes occurred slowly,allowing plants and animals to adapt to the newenvironment or move someplace else.

Plants and animals may not be able to reactquickly enough to survive if future climatechanges occur as rapidly as scientists predict.


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Sea Level Rise

Global Warming may make the sea levelbecome higher. Why?

Warmer weather makes glaciers melt.

Melting glaciers add more water to the

ocean.

Warmer weather also makes water expand.

When water expands in the ocean, it takes

up more space and the level of the sea

rises.


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Rising Sea Levels

When earths temperature rises, sea level is likely torise too:

Higher temperature sea water to expand in

volume

Ice caps at poles to melt


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Sea Level Rise

Sea level may rise between several inches and asmuch as 3 feet during the next century.

Coastal flooding could cause saltwater to flow into

areas where salt is harmful, threatening plantsand animals in those areas.

Oceanfront property would be affected by

flooding.

Coastal flooding may also reduce the quality ofdrinking water in coastal areas.

C d F d S l


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Crops and Food Supply

Global warming may make the Earth warmer in

cold places.

People living in these areas may have the chance

to grow crops in new areas. But global warming might bring droughts to other

places where we grow crops.


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Consequences of

Global Warming


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M lti Gl i Mt Kili j


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Melting GlaciersMt. Kilimanjaro

Drought in Africa


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Drought in Africa

Lake Faguibine Lake Chad

Wh t Mi ht H ?


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What Might Happen?

This warming trend is expected to bring droughtsand flooding of low lying coastal areas as the polar

ice caps melt and raise sea level.

The expected negative impact of the greenhouse

effect on human life has been assessed by some

scientists to be second only to global nuclear war.


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Climatic Change

Global warming will lead to an increase in theevaporation of water more water vapour.

With more water vapour, more rain fall is expected.

But it is not evenly distributed:

Dry areas severe drought condition, water

shortage and heat waves occurs Wet areas floods and avalanches (landslides)


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Climatic Change

Other problems may arise: Destroy food crop rice, wheat and corn

Affect animals need to migrate

Encourage growth of weed and pests may

lead to diseases like dengue fever, cholera

which are deadly.


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Possible Solutions to

Global Warming

Mitigation of Global Warming


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Mitigation of Global Warming

Conservation Reduce energy needs

Recycling

Alternate energy sources Nuclear

Wind

Geothermal

Hydroelectric

Solar

Fusion?

Storage of CO2in Geological Formations
http://upload.wikimedia.org/wikipedia/commons/4/44/Recycle001.svg


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g 2 g

1. Depleted oil and gas reservoirs

2. CO2in enhanced oil and gas recovery

3. Deep saline formations(a) offshore (b) onshore

4. CO2in enhanced coal bed methane recovery

Adapted from IPCC SRCCS Figure TS-7

3a2

3b 14

What can we do about it?


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What can we do about it?

There are many little things that we can do tomake a difference to reduce the amount ofgreenhouse gases that we put into theatmosphere.

Many greenhouse gases come from things wedo every day.

Driving a car or using electricity is not wrong.We just have to be smart

Eg. Try carpooling

Ways you can help make our planet


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better.

ReadLearning about the

environment is very important.

Save ElectricityWheneverwe use electricity, we help put

greenhouse gases into the air.Turn off lights, the television and

the computer.


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better.

RecycleWhen you recycle, you send less trashto the landfill and you help save natural

resources like trees and elements such as

aluminum.

Recycle cans, bottles,

plastic bags and newspapers.



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better.

When You Buy, Buy CoolStuff

Buy Products that dont use as

much energy

Buy recyclable productsinstead of non-recyclable ones.

Solar Energycan be used

to heat homes, buildings,

water and to make electricity.



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better.

Carscause pollution and release a lot

of greenhouse gases into the air.

Some cars are better for the environment

They travel longer on a smaller amount of

fuel. They dont pollute as much.

Using these cars can help reduce can helpreduce the amount of greenhouse gases in

the air.

Wh t l d ?


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What else can we do?

To reduce the emission of greenhouse gases International efforts:

Kyoto treaty (1997) was started to reduce

emission of greenhouse gases by 5% of

1990s levels by 2012.

Worlds major polluters

Summary / Conclusion


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Environmental Crisis will affect us: Health

Air pollution asthma or other

respiratory problems

Water pollution poison our food sourcee.g fish

Destruction of forest lost of possible

medical solutions

Property

Floods property lost

Pollution destroy streets and beaches

Soil erosion desertification, lost of farm

lands


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Environmental Crisis will affect us:

Economic Costs

Lost in terms of monetary values, industry

and businesses.

Money need to be spent to restore theoriginal

Public Health Services need to be

provided by the government.


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Global Warming A Quick Poll


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Global Warming, A Quick Poll

Is global warming real?a) Yes

b) No

How much has the averagetemperature of the Earth risen inthe last 100 years?

a) ~ 0.5C

b) ~ 1.0C

c) ~ 5.0C

d) ~ 10.0C

As far as we know, this is the highesttemperature ever recorded inEarths history.

a) Yes.

b) No.

Who is to blame?a) Human activities

b) Nature causes

c) ET

d) NoCanTell!

What is to blame?

a) Ozone

b) CO2

c) H2O

d) O2e) NoCanTell. It is real

complicated!

How About The CO2 Cycle?


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2

If Earth warms up a bit, then carbonate minerals form in the oceans at a higher

rate.

The rate at which the oceans dissolve CO2gas

increases, pulling CO2out of the atmosphere.

The reduced atmospheric CO2concentration leadsto a weakened greenhouse effect that counteracts

the initial warming and cools the planet back

down.

If Earth cools a bit,

carbonate minerals form more slowly in theoceans.

The rate at which the oceans dissolve CO2gas

decreases, allowing the CO2released by volcanism

to build back up in the atmosphere.

The increased CO2concentration strengthens the

greenhouse effect and warms the planet back up

The CO2 cycle acts as a thermostat that regulates the temperature of

the Earth


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The Earths Atmosphere
http://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Earth%27s_atmosphere


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The Earth s Atmosphere

78% Nitrogen

20% Oxygen

1% Argon 0.03% CO2

Trace Elements

The Precious Envelope

Helium

Nitrogen

Oxygen

Water

vapor

Argon

Neon

Carbon

dioxide

Air
http://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Earth%27s_atmosphere


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Copyright 2007 Pearson Benjamin Cummings. All rights reserved.

Component Percent composition

Nitrogen, N2 78%

Oxygen, O2 21%

Argon, Ar 0.9%

Water, H2O 04% (variable)

Carbon dioxide, CO2 0.034% (variable)


From Space


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Light from

the sun Reflected heatabsorbed by

atmosphere

Reflected heat lost to

outer space

Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 392

Global Warming

The Greenhouse Effec t
http://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Global_warminghttp://en.wikipedia.org/wiki/Greenhouse_effecthttp://en.wikipedia.org/wiki/Greenhouse_effect


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HIGH ENERGY, SHORT lLIGHT PASSES

EASILY THROUGH ATMOSPHERE

ENERGY RELEASED

AS HEAT

LOWER ENERGY, LONGER l

LIGHT IS BLOCKED BY CO2

AND CH4; ENERGY DOESNT

ESCAPE INTO SPACE;

ATMOSPHERE HEATS UP

CO2

MOLECULES

http://en.wikipedia.org/wiki/Greenhouse_effecthttp://en.wikipedia.org/wiki/Greenhouse_effect


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GreenhouseGases



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Ozone

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 309

C b Di id L l


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Carbon Dioxide Levels

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 310

350

300

250

1000 1500 2000

Year

Atmospheric

CO2

(p

pm)


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(a) Records from Antarctic ice cores (1006-1969 A.D.) (b) Records from monthly air samples, Mauna Loa

Observatory, Hawaii (1958-2002)

Copyright 2007 Pearson Benjamin Cummings. All rights reserved.


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Why more CO2in atmosphere now than 500 years ago?

burning of fossil fuels deforestation

* The burning of ethanol wont slow greenhouse effect.

C2H5OH + O2 CO2 + H2O

-- coal

-- petroleum

-- natural gas

-- wood

-- urban sprawl

-- rain forests

-- wildlife areas

Greenhouse Effect350

eric

pm)
http://en.wikipedia.org/wiki/Deforestationhttp://en.wikipedia.org/wiki/Fossil_fuel


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FACT: 15% increase in [CO2] in last 100 years

Cause: Change from agricultural to industrial lifestyle

Burning of fossil fuels (petroleum, coal) Increase CO2emissions (cars, factories etc)

Deforestation

Effects: Global warming

Melt polar ice caps flooding at sea level

Warming oceans more powerful storms

Greenhouse Effect300

250

1000 1500 2000

Year

Atmosphe

CO2

(pp

Greenhouse Effect


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Children and pets left unattended in vehicles with windows

rolled up can die from high temperature in vehicle.

Carbon dioxide in atmosphere traps heat and acts like aglass cover holding in the heat on planet Earth.

What can we do?


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insulate home; run dishwasher full;

avoid temp. extremes (A/C & furnace);

wash clothes on warm, not hot

mow lawn less often (small engines)

1. Reduce consumption of fossil fuels.

2. Support environmental organizations.

3. Rely on alternate energy sources.

bike instead of drive;

carpool;

energy-efficient vehicles

At home:

On the road:

solar, wind energy, hydroelectric power

Sources of Energy


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Documents

Lecture 13Fuel Cell Lectures