CI POLLUTION NOTES BY MISS CHOHAN
POLLUTION
The main types of pollution discussed on the GCSE syllabus are:
1. Global warming
2. Global Dimming
3. Production of toxic Carbon monoxide
4. Acid rain
5. Nitrogen oxides
The levels of oxygen and carbon dioxide have remained fairly constant for many years due to the
carbon cycle.
In other words the amount of energy given out in respiration and combustion was equal to the amount
of CO2 taken in by plants during photosynthesis
However in the last 150 years (since the industrial revolution) the levels of CO2 has significantly
risen.
This is mainly due to:
1. Increased burning of fossil fuels
2. Deforestation
3. Respiration
1. Fossil fuels when burn completely in a plentiful supply of oxygen forms CO2 which
causes global warming
2. Deforestation means there are less crops to take in CO2 for photosynthesis
3. Respiration, though a natural process has increased CO2 levels due to an increase
in population
CI POLLUTION NOTES BY MISS CHOHAN
Higher level of carbon dioxide causes the
temperature of the Earth to rise. Heat can not
escape as easily
There is evidence to suggest that the Earth is
warming but scientists do not all agree on the
cause of this.
Many think that it is due mainly to increased levels
of carbon dioxide in the atmosphere as a result of
the combustion of fossil fuels and deforestation.
As a result the carbon cycles has been imbalanced
Higher level of carbon dioxide causes the
temperature of the Earth to rise. Heat
cannot escape as easily
CI POLLUTION NOTES BY MISS CHOHAN
THE EFFECTS OF GLOBAL WARMING
CCS (CARBON CAPTURE STORAGE)
Global warming can cause :1. Changing weather patterns e.g. drier, hotter summers in
some parts of the world leading to drought.
Scientists are thinking of storing the CO2
2. Flooding due to increase rainfall in some areas
produced by burning fossil fuels under the
sea or underground in geological formations
3. Quicker melting of ice caps and glaciers
4. Rising sea levels
 When there is not enough oxygen (say a blocked pipe or in a faulty heater) when a fossil
fuel burns we get incomplete combustion.
 Instead of forming CO2 gas we form either CO gas (carbon monoxide) or carbon
particulates (soot)
Carbon Monoxide - TOXIC
-
This is a toxic gas and can kill
The gas is odourless and colourless
which makes it even more deadly
Carbon monoxide gas stops oxygen
going around the body and hence
staves the brain of oxygen
Carbon Particulates – GLOBAL DIMMING
-
Carbon is a black solid
It blocks out sunlight
Over the last 50 years there is
25% less sunlight reaching the
Earths surface
CI POLLUTION NOTES BY MISS CHOHAN
In fuels such as oil and petrol there are impurities (i.e. oil is not pure hydrocarbons), compounds
such as sulphur and nitrogen are present. When these burn they form polluting gases, such as
sulfur dioxide and oxides of nitrogen.
Acid rain forms when sulfur dioxide is released from factories. Acid rain forms when sulfur
dioxide reacts with rain to form sulfuric acid
It kills plants (forests) and aquatic life such as fish. It also damages buildings and statues made
of limestone (calcium carbonate) and metals e.g. bridges.
FLUE GAS DESULPHURISATION (FGD) – Also known as a scrubber
This is the process of removing sulphur dioxide from exhaust flue gases of fossil fuel
powered plants
The scrubber is packed with calcium oxide, which is a base. This base neutralises the
acidic SO2 gas and stops it from going into the atmosphere to cause acidic rain.
CI POLLUTION NOTES BY MISS CHOHAN
 These are formed in a car engine.
 High temperatures inside an engine allows nitrogen and oxygen from the air to react
together to form nitrogen oxides
 Nitrogen oxides are toxic, can cause acid rain and can trigger asthma attacks.
CATALYTIC CONVERTERS
Catalytic converters
in cars remove NOx
CI POLLUTION NOTES BY MISS CHOHAN
CI POLLUTION NOTES BY MISS CHOHAN