C1- Air Quality

C1- Air Quality

The Evolution of the Atmosphere
1. Phase 1- Volcanoes gave out Gases
  1. 1) Earths surface was originally molten for millions of years. So hot that any atmosphere just 'boiled away' into space.
  2. 2) Things cooled down and a thin layer of crust formed- volcanoes kept erupting.
  3. 3) Volcanoes gave out lots of gas- including carbon dioxide, water vapour and nitrogen.
    1. We think this is how atmosphere was formed.
  4. 4) Early atmosphere probably mostly carbon dioxide and water vapour- virtually no oxygen
  5. 5) Oceans formed when water vapour condensed when earth cooled
2. Phase 2- Green Plants Evolved and Produced Oxygen
  1. 1) Green Plants evolved over most of Earth- happy in CO2 atmosphere.
  2. 2) A lot of early CO2 dissolved into ocean. Green plants removed CO2 produced O2 through photosynthesis.
  3. 3) Plants died- buried under layer of sediment- carbon removed from air becomes locked up in sedimentary rock as insoluble carbonates and fossil fuels.
3. Phase 3- Complex Organisms Evolved
  1. 1) Build up of oxygen in atmosphere killed off some early organisms- couldn't tolerate it- more complex organisms evolved.
  2. 2) Virtually no CO2 left
Atmosphere Today
1. 78% Nitrogen 21% Oxygen 1% Argon
2. Also contains small amounts of co2 and other gases- also varying amounts of water vapours
3. Concentration of nitrogen, oxygen and argon remains pretty constant.
4. Human activity adding small amount of pollution each year. 5 main pollutants....
  1. Carbon Dioxide
  2. Carbon Monoxide
  3. Particulates
  4. Sulfur Dioxide
  5. Nitrogen oxides
5. Pollutants come form different sources e.g. burning fuels from power stations and veichles
6. Gases and Particulates can be released by nature e.g. volcanoes
7. Some pollutants directly harmful to humans- cause disease or death when breathe in large enough amounts- carbon monoxide reduces amount of oxygen blood carries- flu like symptoms eventually death
8. Pollutants can harm us indirectly- damage environment- e.g. climate change
Chemical Reactions
1. All substances made from tiny particles- atoms
2. When atoms join together make molecules
3. Almost all chemical reactions involve atoms changing places.
  1. Atoms from substances you start off with (reactants) rearrange themselves to form different chemicals.
    1. New chemicals called products.
4. No atoms disappear during a reaction.
  1. Same atoms in reactant as in product.
  2. Mass also stays the same.
5. Reactants and products have very different properties.
  1. Atoms rearrange in reaction.
    1. Products formed = own properties.
      1. Can be very different from reactants properties.
Fossil Fuels
1. They are hydrocarbons
  1. Majority of fuels contain just carbon and hydrogen
  2. Coal different- not hydrocarbon mostly carbon.
  3. React quicker in pure oxygen than in air
2. Formed from remains of dead plants and animals over millions of years
3. Burning fuels is an example of Oxidation
  1. Combustion (burning) - chemical reaction
  2. hydrocarbons burn- hydrogen combines with oxygen- make s hydrogen oxide (water)
    1. Carbon combines with oxygen to create carbon dioxide.
  3. Any reaction when oxygen is added is called an oxidation reaction
    1. Reactions when oxygen is lost are called reduction reactions.
    2. Combustion is an example of combustion
Air pollution - Carbon
1. Different forms or Carbon Pollution cause different problems
  1. All fossil fuels contain carbon- produce pollutants containing carbon
  2. If fuel burnt with lots of oxygen nearly all carbon reacts with it
    1. Produces Carbon dioxide that increases the amount found naturally in the atmosphere.
      1. All pollutants
      2. Carbon dioxide can be removed naturally through photosynthesis and dissolving in rainwater, sea, lakes and rivers.
        However amount still increasing through burning fossil fuels.
        Causes greenhouse effect - global warming.
  3. Not enough oxygen- small amounts of carbon monoxide and carbon particles are produced
    1. All pollutants
    2. Carbon monoxide produced from incomplete combustion.
      1. Poisonous- make you drowsy, headachy and even kill.
    3. Particles of Carbon formed when no oxygen to react with.
      1. Float around- fall on things making them look dirty.
Air pollution- Sulfur
1. Sulfur pollution comes form impurities in fuels.
  1. Carbon based fuels contain lots of impurities as they're extracted straight from earths crust.
    1. Many impurities are harmless but some contain sulfur.
  2. When sulfur burns it combines with oxygen to create sulfur dioxide.
    1. Usually ends up in atmosphere.
2. Causes acid rain.
  1. Sulfur usually leaves atmosphere through acid rain
    1. Bad for environment.
      1. Causes lakes to become acidic- kills plants and animals, damages buildings and statues made for certain types of stone.
Air Pollution- Nitrogen.
1. Doesn't come from fuel- formed from nitrogen in air when fuel is burnt.
  1. Nitrogen and oxygen from air react in car engines.
    1. Produces nitrogen oxides- nitrogen monoxide and nitrogen dioxide
      1. Both pollutants- usually spewed straight into atmosphere.
2. Causes acid rain.
Reducing pollution
1. Use less electricity.
  1. Less fossil fuels will need to be burnt.
2. Motor vehicles have more efficient engines.
  1. Burn less fuel- create less pollution.
3. Use more biofuels.

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	Created by Charlotte johnson almost 11 years ago