C13

• Earths early atmosphere formed by volcanic activity
• INtense volcanic activity erased gases that formed the early atmosphere
• As plants spread over the earth, the levels of oxygen in the atmposphere increased
• As the earth cooled down the water vapour in the atmosphere condensed to form oceans
• Algae used energy transferred as light waves from the sun to photosynthesise
• Photosynthesis by algae and plants decreased the percentage of CO2
• Formation of sedimentary rocks and fossil fuels that contains carbon removed CO2 from the atmosphere
• Fossil fuels coal, crude oil and natural gas were formed from plant and animal remains
• approximate 80% nitrogen and 20% oxygen
• Carbon dioxide, methane and water vapour are greenhouse gases
• Burning of fossil fuels increased carbon dioxide intake of our atmosphere
• Deforestation means less CO2 is removed from air as photosynthesis is reduced
• increasing amounts of methane is due to animal farming leading to more emissions and decomposing of waste so more decomposition of rubbish in landfills
• consequences of rising lvls of greenhouse gases are rising se levels, more storms, flooding and meting ice caps
• carbon footprint is the total amount of CO2 and other greenhouse gases emitted over its full life cycle
• Biofuels are carbon neutral as 100% of the carbon dioxide released during combustion is reabsorbed by plants
• Particulates can cause lung damage
• At the high temperatures produced when fuels burn, oxygen and nitrogen in the air may combine to form nitrogen oxides which cause acid rain
• Incomplete combustion of hydrocarbons are carbon monoxide, unburnt hydrocarbons and particulates that contain soot (carbon)