C1 air quality

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  • C1 air quality
    • 1. The evolution of the atmosphere
      • The atmosphere was originally molten for millions of years
      • Eventually, the earth cooled down and formed a crust
      • Volcanoes gave out gases. And this was how our atmosphere was formed
        • Carbon dioxide
        • Water vapour
        • Nitrogen
      • The early atmosphere was probably mostly CO2 and water vapour. With virtually no oxygen
      • Photosynthesising organisms had evolved
      • A lot of early CO2 had been;
        • Dissolved into the oceans
        • Removed by photosynthesis
        • Plants had been buried under layers of sediment, which formed carbonate fossils
      • The build up of oxygen had killed off many early organisms. Allowing more complex organisms to evolve
      • There is virtually no CO2 left now
    • 2. The atmosphere today
      • The earth is surrounded by the air
      • Nitrogen=78%
      • Oxygen=21%
      • Argon=1%
      • The atmosphere also contains
        • Carbon Dioxide
        • Various other gases
        • Varying amounts of water vapour
      • Human activity is changing the atmosphere. By adding;
        • Carbon dioxide
        • Carbon monoxide
        • Particulates
        • Sulfur dioxide
        • Nitrogen oxides
      • Some gases are naturally produced. E.g volcanoes
    • 3. Chemical reactions
      • Chemical reactions happen when atoms are rearranged
      • The mass is conserved during a chemical reaction
      • The reactants and products have very different properties
    • 4. Fossil fuels
      • Fossil fuels are hydrocarbons
        • Hydrogen
        • Carbon
      • Hydrocarbons are formed from the remains of dead plants and animals over millions of years
      • The only difference between fuels is the size of the hydorcarbons
      • Combustion is an example of oxidation
      • Reactions that result in a loss of oxygen is called reduction
      • Hydrocarbons burn more rapidly in pure oxygen
    • 5. Air pollution - carbon
      • Fossil fuels are burnt to release energy
      • We burn fossil fuels to power vehicles and to produce electricity
      • Carbon dioxide
        • CO2 is formed when a fuel is burnt when there is plenty of oxygen available
        • CO2 can be removed naturally by photosynthesis or dissolving into oceans
        • CO2 is a contributing factor to global warming
      • Carbon monoxide
        • It is produced when there is not enough oxygen available when a fuel is burnt
        • It is a poisonous gas, which can make you drowsy and headachy
      • Particulate carbon
        • Produced when a fuel is burnt incompletely
        • They cause dirty buildings
    • 6. Air pollution - sulfur
      • Some fuels contain traces of sulfur
      • Sulfur pollution casues acid rain
      • The sulfur given off reacts with the moisture in the clouds, which makes acid rain
      • Acid rain causes lakes to become acidic, killing plants and animals.
      • Acid rain indirectly harms humans
    • 7. Air pollution - nitrogen
      • It is produced when a fossil fuel is burnt at high temperatures
      • This usually happens in car engines
      • Nitrogen monoxide is formed when the air is exposed to very high temperatures
      • Nitrogen dioxide is formed when there is nitrogen monoxide, which goes on to react with more oxygen in the high temperatures
    • 8. Reducing pollution
      • The simplest way to reduce the pollution is to use less electricity
      • Sulfur can be removed by two methods
        • Seawater: The sulfur dioxide is dissolved in seawater, producing CO2, water and dissolved sulfate
        • An alkaline slurry; The slurry is sprayed onto the gases and the sulfur dioxide reacts with the calcium oxide. A solid waste product (Calcium sulfite) is formed
      • Many cars are fitted with catalytic converters
        • These convert harmful nitrogen monoxide into harmless nitrogen and oxygen
      • MOT tests are used to chck a cars legal limit of polluting emissions.
      • If more people used public transport, it could reduce pollution
      • Car engines can be run by burning biofuels and using electric engines

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