Chemistry atmosphere

• Atmosphere contains

  20% oxygen

  80% nitrogen

  1% trace gasses e.g carbon dioxide
• process of oxygen in earth atmosphere increased

  • green plant life evolved 2.7 billion yrs ago
  • began to photosynthesis
  • converted into carbon dioxide to oxygen
  • proportion of oxygen increased
• How oxygen increased:

  • algae and plants produced oxygen now in atmosphere by photosynthesis
• The greenhouse gas effect:

  1. electromagnetic radiation from the sun passes through the earths atmosphere
  2. earth absorbs some radiation and warms up but some is radiated from the earth as infrared radiation
  3. some of this IR radiation absorbed by greenhouse gases in atmosphere
  4. atmosphere warms up leading to greenhouse effect and global warming
• Human activities that contribute to increases of greenhouse gases:

  • driving (co2)
  • consuming electricity (co2)
  • raising livestock (co2)
  • decay of organic waste in landfill sites (CH4)
• Carbon footprint - measure of how much CO2 an individual or organisation produces over time
• carbon credits - allow companies to offset their emissions by investing in projects that reduce greenhouse gases elsewhere
• Global climate change is the change in the average weather patterns over a long period of time.
• What is carbon footprint?

  The total amount of greenhouse gases emitted directly or indirectly by an individual, organization, or product.
• Atmospheric pollutants from fuels:

  • combustion of fuels major source
  • most fuels (including coal) contain carbon or hydrogen may contain sulfur
  • gases released into the atmosphere
• Properties and effects of atmospheric pollutants

  • carbon monoxide; toxic gas which is colourless and odourless
  • sulfur dioxide and oxides of nitrogen: cause acid rain
  • particles: cause global dimming
• What is acid rain?

  Rain that is acidic due to dissolved gases such as sulfur dioxide produced from the burning of fossil fuels.