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The atmosphere
The atmosphere protects the earth from the sun's harmful rays. Shooting stars
from space, which can be seen on a clear night, burn up when they enter the
atmosphere. The atmosphere protects life on Earth by absorbing ultraviolet
solar radiation, warming the surface through heat retention (greenhouse
effect), and reducing temperature extremes between day and night (the
diurnal temperature variation).
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Troposhere
Stratosphere
Ionosphere
The stratosphere
The stratosphere is a layer of Earth's atmosphere. The stratosphere is the
second layer, as one moves upward from Earth's surface, of the atmosphere.
The stratosphere is above the troposphere and below the mesosphere.
Ozone, an unusual type of oxygen molecule that is relatively abundant in the
stratosphere, heats this layer as it absorbs energy from incoming ultraviolet
radiation from the Sun.
The ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the
mesosphere, thermosphere and exosphere, distinguished because it is ionized
by solar radiation. It plays an important part in atmospheric electricity and forms
the inner edge of the magnetosphere. It has practical importance because,
among other functions, it influences radio propagation to distant places on the
Earth. In ionosphere we find the Ozone layer
What is air?
Air is made up mostly of Nitrogen and Oxygen.
When we breathe we use Oxygen and give off Carbon Dioxide. The
plants and trees absorb the Carbon Dioxide and give off Oxygen.
This layer is the nearest to the earth surface,that's why most effects on
our life depends on it.
Among them the most harmful ones are the acid rains and the
greenhouse effect.
Ozono is a gas found 10 to 15 kilometers above the Earth.
It protects us from the sun's harmful ultra violet rays .
The ozone layer can be damaged by pollution, especially CFC's found in
Aerosols
Look out for 'environmentally friendly 'and ' ozone friendly'
Products.
The cause of
Ozone Layer Depletion
Chluorofluorocarbons (CFCs), such as frigerants and propellants in
Aerosolcans, release chlorine when they break down.
Rising to the upper Atmosphere, the chlorine reacts with ozone (O3)
gas, reducing it to O2 gas.
The ozone layer in the upper atmosphere protect life on earth from
the harmful ultraviolet rays in sunlight.
Multinational agreement was reached in 1987 to phase out the use
of these chemicals. However quantities of these chemicals already in
the air would continue to deplete the ozone layer for decades.
Carbon dioxide and other gases added to
atmosphere may cause global warming
The addiction of CO2 to the atmosphere by
cellular respiration roughly balances the removal
of carbon dioxide by photosynthesis.
All fossil fuels and many other fuels contain carbon.
As these fuels are used they are releasing more and more
carbon dioxide into the atmosphere.
sun
Carbon dioxide
Released into
atmosphere
Carbon dioxide takenin
by plants for
photosynthesis
respiration
plants
dead material
Animals
and humans
Fossil flues
Human energy use
Carbon dioxide and other gases added to the atmosphere may cause
global warming.
The rise of the agriculture and the Industrial Revolution triggered
some profound environmental changes. A change that could alter the
entire biosphere is rapid global warming.
The addition of CO2 to the atmosphere by cellular respiration roughly
balances the removal of CO2 by photosynthesis. What is troubling is
the current rate of increase in atmospheric CO2.
Carbon Dioxide
Other Gases
Carbon Dioxide is one of several so-called greenhouse gases
(molecules that can trap heat and cause atmospheric warming,
known as greenhouse effect).
CO2 absorbs infrared radiation and slows its escape from Earth.
Fossils fuels power most of our industries, agricultural equipements
and automobiles and they heat most of our homes.
One of the major side effects of the combustion of fossil fuels is
an increase in atmospheric CO2
Other greenhouse gases are methane and nitrous oxide, both of
which are also increasing in the atmosphere as a result of fossilfuel consumption, industry and agriculture.
We must stop chopping down the rain forests as many rare species will become extinct
and life giving oxygen which is produced by the trees will be reduced.
In addition to flooding, a warming trend might alter patterns of global precipitation.
For instance, the grain belts of the central United States and centra Asia might
become much direr and unable to support the crops currently grown there.
Furthermore, forested areas in seminarid zones could lose their trees and become
deserts.
Studies of climatic
changes through
geological time
mathematical models
lead some
climatologists to
predict that in the
next 50-100 years, at
the present rate
greenhouse gases
are increasing,
atmospheric
temperatures could
rise by about 2-5°C. It
is also possible that
as the temperature of
the atmosphere
increases,
populations of soil
bacteria will increase
and in turn produce
even more CO2 and
methane.
Acid rain is produced when poisonous gases from
power stations and cars react together and
dissolve in rainwater . The resulting rain and snow
is often as strong as lemon juice. This rain kills
trees , dissolves stones on historic buildings ,
enters rivers and streams and kills the fish.
Emissions of the gases and nitrogen oxides contribute to the
international problem of acid rain pollution . Sulphur dioxide
emissions arise during combustion of fossil fuels . Including
coal , oil and natural gas . Oxidation of sulphur dioxide forms
Sulphur dioxide (SO2), a colourless gas. It is soluble in water
and it is transformed into sulphuric acid (H2SO4), which falls
as acid precipitation or 'acid rain'.Large quantities of sulphur
Dioxide are released naturally when volcanoes erupt. The
problem of acid rain is not a recent development,but we are
much more aware of the damage caused by acid rain
nowadays.
The Acropolis was built over 2000 years ago. The damage done is largely
due to the pollution caused by cars and other vehicles in Athens -the most
polluted city in Europe . Car engines burn petrol as a fuel and release
acidic gases such as sulphur dioxide into the atmosphere. May other
countries have also noticed an acceleration of damage to their cultural
heritage.
How can pollution problems
cause acid rain?
About 80% of the air is nitrogen.The high temperatures cause some of this
nitrogen oxides to produce nitrogen oxides.These are some of the ways levels
of nitrogen oxides can be reduced:
In power stations
 Eliminate excess air by using the minimum amount of air needed for combustion
 Lower the combustion temperature

In cars:
Change the air
 Recirculate exhaust fumes
 Use catalytic converters

These are some ways we can reduce levels of sulphur dioxide in the air :
Burn less fossil fuel
 Fuel desulphurisation
 Sulphur reduction during combustion by the addition of lime to coal
duriing combustion
 Fuel gas removal

How to treat damaged areas
Fertilise damaged conifer forests with calcium,magnesium,potassium,zinc and
manganese.
Spread lime on affected lakes and forest.

SPECIESOF ANIMALSAND PLANTS
How does acid rain affect fish and other aquatic
organisms?
Acid rain causes a variety of effects that harm or kill individual
fish and reduce fish population numbers. In some cases,acid
rain completely eliminates some fish species from certain
bodies of wother and resultes in decrased biodiversity. As racid
rain flows through soils, aluminum is released from the soli into
the lakes and streams, resulting in a lower ph and a higher
alluminium level. Low ph and increased aluminium levels are
directly toxic to fish and cause them chronic stress.
Some types of plants and animals ar able to tolerate acidic
waters. Others, however, are acid-sensitive and will die as
the ph falls. Generally, the young of most species are more
sensitive to envionmental conditions than adults.
BIOLOGICAL INDICATORS: SIGNS OF
PULLUTION
Biological
indicators are useful for assessing levels of
pollution
1. Lichens are sensitive to sulphure dioxide. By observing
the type of lichens growing locally, environmental
scientists can monitor the level of sulphur dioxide
pollution.
2. Mosses are sensitive to air pollution and have
disappeared from many metropolitan and industrial areas
Don't throw rubbish on the floor
Don't use the car when you can walk or
cycle: use public transport
DON'T HAVE A BATH, HAVE A SHOWER!
SHARE A CAR WITH FRIENDS
Home
Home
BUY LOCAL FOOD, EAT FRUIT AND
VEGETABLES IN THEIR SEASON.
Recycle paper, glass, plastic and reuse.
Don't waste water
turn tap off, don't leave water on.
Switch lights off when you leave a room
use less electricity
Don't leave appliances stand-by
Use only “Ozone Friendly” products