Chemistry of the Atmosphere

• the atmosphere contains:

  • 4/5 of nitrogen
  • 1/5 of oxygen
  • other gases such as carbon dioxide, methane and water vapour
• there was lots of volcanic activity billions of years ago
• volcanic activity releases gases which formed the early atmosphere
• water vapour from volcanic activity condensed to make oceans
• volcanic activity also produced nitrogen
• carbon dioxide reduced as the oceans formed
• oxygen in the atmosphere was produced as algae and plants photosynthesised
• animals evolved as plants evolved and so more oxygen was produced
• carbon was decreased by the formation of sedimentary rocks and fossil fuels
• carbon dioxide, methane and water vapour act as a insulating layer which allows the Earth to be warm
• Examples of deposits:

  • limestone
  • coal
  • crude oil
  • natural gas
• limestone is a sedimentary rock which is made up of calcium carbonate deposits
• coal is a sedimentary rock that is made up from thick plant deposits
• crude oil and natural gas is formed from plankton
• greenhouse gases maintain high temperatures to support life
• examples of greenhouse gases

  • methane
  • water vapour
  • carbon dioxide
• greenhouse gases absorb long wavelength radiation which gets reflected back off the Earth. This thermal radiation results in Earth's surface being warmer
• human activity that contributes to greenhouse gases:

  • deforestation
  • burning fossil fuels
  • agriculture
  • waste
• deforestation contributes to greenhouse gases because fewer trees mean less carbon dioxide being removed from the atmosphere
• burning fossil fuels contributes to greenhouse gases as carbon in these fuels is released as carbon dioxide
• agriculture contributes to greenhouse gases as more farm animals means that more methane is produced
• waste contributes to greenhouse gases as more landfill sites means that more methane and carbon dioxide is released by waste
• climate change is caused by the increase in average global temperature
• climate change can cause:

  • polar ice caps melting
  • changes in rainfall patterns
  • increase in extreme weather
• polar ice caps melting causes a rise in sea levels and more flooding
• changed in rainfall patterns means that some areas may get too much or too little water, which affects their ability to produce food
• carbon footprint is the total amount of carbon dioxide and other greenhouse gases released over the full life cycle of a product
• carbon footprint can be reduced by reducing carbon dioxide and methane emissions
• we can reduce emissions by:

  • using renewable energy resources
  • governments taxing people for greenhouse emissions
  • conserving energy
  • governments placing a limit on all greenhouse gases made
• reducing greenhouse emissions is limited because:

  • a lot of work is needed to replace technology
  • it can impact economic growth
  • some people don't want to change their current lifestyle
• carbon monoxide is a toxic gas which is colourless and odourless, making it hard to detect
• sulfur dioxide and oxides of nitrogen can cause respiratory issues and acid rain
• particulates can cause global dimming and health issues
• fossil fuels contain hydrocarbons
• during combustion of fossil fuels, the carbon and hydrogen atoms are oxidised, which releases carbon dioxide and water into the atmosphere
• incomplete combustion occurs when there is not enough oxygen so not all the fuel burns
• incomplete combustion is dangerous as it can produce carbon monoxide
• if particulates are inhaled, they can get stuck to the lining of the lungs and cause damage
• global dimming is when sunlight reflects into space so less light reaches earth
• carbon monoxide can stop blood from carrying oxygen around the body