Chemistry Of The Atmosphere

• phase 1

  -covered in volcanoes

  -mostly carbon dioxide with little oxygen

  -volcanoes released nitrogen, water vapour and small amounts of ammonia and methane
• phase 2

  -water vapour condensed and forms oceans

  -co2 dissolves in oceans and forms carbon precipitates that formed sediments on sea beds

  -algae and plants evolved to do photosynthesis

  -marine animals evolved and skeletons contained carbonates

  -carbon became locked in rocks after organisms died
• sedimentary rocks, oil and gas formation


  plants, plankton and marine animals die, fall to seabed and get buried by sediment. become compressed. trap carbon in them and reduce co2 levels in the atmosphere
• crude oil and natural gas

  formed from deposits if plankton. form reservoirs in seabed when they get trapped under rock
• coal

  sedimentary rock made from thick plant deposists
• limestone

  sedimentary rock, calcium carbonate deposits and shells and skeletons of marine organisms
• phase 3

  -green plants and algae- photosynthesis

  -as oxygen levels increased more complex life evolved

  -reached similar composition to todays- 200 million yrs ago
• composition of earths atmosphere

  80% nitrogen, 20% oxygen, small amounts of other gases: water vapour, carbon dioxide, noble gases
• greenhouse effect

  -particles absorb certain frequencies of radiation

  -dont absorb short wavelength from the sun

  -absorb long wave-length that gets reflect off earth

  -re-radiate towards earth

  -thermal radiation- warming of earth's surface
• human activities that increase greenhouse gases

  deforestation- less co2 removed via photosynthesis

  fossil fuel burning- carbon that was locked up is released as co2

  agriculture- increases methane levels through digestive processes

  waste- landfill sites- more co2 and methane released by decomposition of waste
• recently earths temperature as been increasing despite the fact it fluctuates naturally. extra co2 leads to climate change. many variables so difficult to understand. may be some bias in media
• polar ice caps

  melt as temperatures increase

  rise in sea levels

  increased flooding and coastal erosion
• rainfall patterns


  regions may have too little or too much rainfall

  temperature changes

  affects amount of food produced
• storms

  severity and frequency may increase
• species and animals

  increase in temperature and amount of water affects species- differences in distribution
• carbon footprint

  measure of how much carbon dioxide and other greenhouse gases are released during the life-cycle of something
• many different factors affecting carbon footprint so difficult and sometimes impossible to measure. calculate gases released when making something and using something and dispose of it
• reducing carbon footprint

  -renewable energy- wind etc and nuclear instead of fossil fuels

  -efficient processes- cut waste- waste releases methane etc

  -tax companies based off emissions- buy most efficient ones

  -cap on emissions

  -technology that captures co2 produced by burning fossil fuels
• reducing carbon footprint is still difficult

  -work to be done on alt technologies

  -govs are worried about economic impacts on communities- bad for wellbeing

  -hard to make international agreements

  -individuals need to make changes on their lifestyles- difficult to enforce
• combustion of fossil fuels

  fossil fuels contain hydrocarbons which oxidise to form carbon dioxide and water vapour
• incomplete combustion

  not enough oxygen some of the fuel doesn't burn. solid particles of soot (carbon) and unburnt fuel are released as well as carbon monoxide and carbon dioxide
• complete combustion


  plenty of oxygen so fuel burns
• issues with particulates in air

  -if inhaled can get stuck in lungs causing respiratory problems

  -bad for environment, reflect sunlight into space- less reaches earthglobal dimming
• carbon monoxide


  -dangerous for body- stop blood doing its job of carrying oxygen

  -binds to haemoglobin in blood so less oxygen is bale to be transported

  -lack of oxygen- fainting, coma, death

  -no colour or smell and is difficult to detect- more dangerous
• sulfur dioxide

  -combustion of fossil fuels that contain sulfur impurities that get oxidised

  -bad for human health
• nitrogen oxides


  -nitrogen and oxygen in air caused by heat of burning

  -mix with clouds and form dilute sulfuric acid- acid rain

  -kills plants and damages buildings- makes metal corrode

  -bad for human health