Atmosphe and human activity
Structure of the atmosphere
Troposphere
Thermosphere
Temperature
Stratosphere
decreases as height
increases as
Temperature increases
conduction and
slightly with height which is
convection form the
called temperature
earth decreases
inversion
It also contains the ozone
Mesosphere
Temperature falls rapidly
as there is no water
vapor or ozone to
absorb short wave
Temperature rises
rapidly because of the
absorption of
ultraviolet radiation by
atomic oxygen
radiation
Natural green house effect
The earth receives short wave radiation from the sun
Half of the radiation absorbed by the earth surface
20% absorbed by the atmosphere
Green house gases
Natural …..CO2 , methane , ozone
Artificial …….chloroflurocarbons
30% is reflected by clouds and earth surface back into space
As the earth surface warms , outgoing long radiation is emitted back into the
surface
layer
Green house gases absorb some of this radiation and deflect it back to earth
The greater the concentration of green house gases the more effectively they
Absorb most of the
sun UV radiation
return radiation to earth
Smog
The atmospheric pollutants are released in the air when fuels get burned
These gases react with sunlight and its heat to form smog
With the help of high pressure , lack of air flow and temperature inversion layer smog is formed
Atmospheric pollution
Temperature inversion
A weather condition where the air temperature increases with altitude
During day surface is heated
Ozone depletion
When CFCs reach the stratosphere the
ultraviolet radiation breaks them down
releasing chlorine
Chlorine reacts with ozone , breaking down
the ozone molecule to chlorine monoxide and
oxygen depleting the layer and forming a hole
On calm nights earth surface cools quickly and hold cold air near the ground
Cold air is denser so unable to rise
Steep sided valleys increase the strength of inversion layer
The layer is the inversion layer which traps pollutants increasing formation of fog thus increasing smog
Acid rain
Burning of fossil fuels release sulphur dioxide and nitrogen oxides
When these gases mix and react with water vapor in the atmosphere they form weak nitric and sulphuric acids
They are carried by the wind and fall to earth as acid rain
Enhanced green house effect
Created by addition of green house gases to the atmosphere through human
activities
Impact of atmospheric pollution
Smog
Some heat is trapped by green house gases
How human activities increases the green house gases ?
Acid rain
Acidification of ground water
Damage to buildings
Sun burn
Increased rates of skin cancer
Increased mutation
Damage to vegetation
Irritation of eyes
Heat is reflected from earth back to space
This warms up the earth causing global warming
Reduced photosynthesis
Ozone depletion
Respiratory diseases
Short wave radiation from the sun reaches the earth surface
The more greenhouse gases the more heat trapped
Breathing difficulties
Enhanced
global effect
Fish dies
Melting ice sheets
Loss of biodiversity
Rise in sea levels
Migration of people from area
Disruption of food webs
where there is flood
Carbon dioxide - burning fossil fuels and deforestation
Methane - mining , deforestation , burning of permafrost
CFCs - aerosol sprays , air conditioning , fire extinguishers
Nitrogen oxides - vehicle exhaust , chemical fertilizers
Walking or cycling
Ways of reducing carbon dioxide emissions
Tropospheric - chemical reaction involving nitrogen dioxide
Having laws controlling factory emissions
International agreements
Recycling wastes
Renewable resources
Managing atmospheric pollution
Reduce use of fossil fuel and instead use renewable resources
Creation of metro systems and trams that can use biofuels
Reduce the use of CFCs
Use catalytic converters in vehicles to reduce sulphur dioxide emissions
Higher road tax to decrease car ownership
Reasons for difficulty of reducing air pollution
The technology that reduces air pollution is expensive
Abundance of fossil fuels
May impact the economy
Not popular with the public
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