chemistry of the atmosphere

• Nitrogen - 78%

  Oxygen - 21%

  Carbon dioxide - 0.04%

  Argon - 1%


  Traces of hydrogen and helium
• • Volcanic eruptions released atmospheric gases


  mainly CO2

  little O2

  Nitrogen, Methane, Ammonia
• • WHY DID CO2 LEVELS DECREASE?
  • Water vapour condensed to form oceans
  • The CO2 dissolved in oceans forming a weak acid
  • CO2 is a soluble gas


  the dissolved CO2 formed sedimentary rocks like limestone from minerals and sediments

  CO2 is decreased as it's a reactant in photosynthesis
• WHY DID O2 LEVELS INCREASE?

  • plant evolution as the photosynthesise
  • algae forming in oceans 2.7B years ago


  dead algae that fell to the bottom of the sea which had carbon stored within them are now trapped in the ground - the CO2 can't get into the atmosphere

  carbon trapped in fossil fuels
• GREENHOUSE GASES:

  • Water vapour
  • Carbon dioxide
  • Methane


  GREENHOUSE EFFECT:

  The Sun emits radiation, some is reflected by the Earth back into space and some is absorbed by the Earth's surface by greenhouse gases

  The gases re-radiate the radiation in all directions to warm the atmosphere.
• HUMAN ACTIVITIES THAT INCREASE GREENHOUSE GASES:

  • CO2, burning fossil fuels (propane)
  • C3H8 + 5O2 --> 3CO2 + 4H20
  • Deforestation releases trees stored CO2 into the atmosphere


  CH4, cattle produces methane

  landfill sites
• EFFECTS OF CLIMATE CHANGE:

  • Flooding
  • Extreme weather
  • Changes in rainfall
  • Extinction
• FLOODING:

  • high temperatures ->
  • ice caps melt ->
  • sea levels rise ->
  • land gets flooded ->
  • costal erosion & habitat loss
• EXTREME WEATHER:

  • storms->
  • damage
• CHANGES IN RAINFALL:

  • how much rain
  • when it occurs
  • where it occurs
  • heavy rain -> damaged crops
  • lack of rain -> drought
  • affects food production !
• EXTINCTION:

  • climate changing rapidly
  • animals & plants can't adapt fast enough
  • eventually die out
  • survival of the fittest
• ATMOSPHERIC POLLUTANTS:

  • Carbon dioxide
  • Water vapour
  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen oxides
  • Solid particulates (unburned fuel/soot)
• CO2 & H2O vapour

  • produced through complete combustion of hydrocarbon fuels
  • methane + oxygen --> carbon dioxide + water


  greenhouse gases ->

  global warming ->

  climate change
• CO

  • produced through incomplete combustion of hydrocarbon fuels
  • when there's poor oxygen supply
  • methane + oxygen --> carbon monoxide + water


  it's a toxic, colourless, odourless gas

  binds to haemoglobin in blood in replacement of oxygen -->

  difficult to respire.
• -SO2

  • reacts with oxygen in combustion
  • sulfur + oxygen --> sulfur dioxide
  • NOx
  • high temperature from engine ->
  • causes nitrogen to react with oxygen
  • nitrogen + oxygen --> nitrogen oxides


  they both cause respiratory problems

  they both cause acid rain ->

  kills wildlife & damages buildings
• UNBURNED FUEL/SOOT/PARTICULATE CARBON

  • when diesel doesn't react with enough oxygen ->
  • incomplete combustion
  • pollution

  cause lung damage

  global dimming