Atmospheric gases now
- 80% Nitrogen
- 20% Oxygen
- 0-1% other gases e.g. water vapour, carbon dioxide etc.
Early atmosphere
- a lot of carbon dioxide and water vapour
- very little oxygen
Why did oxygen increase and carbon dioxide decrease?
- plants produced oxygen
- carbon dioxide was absorbed by plants and algae (photosynthesis) and sedimentary rocks and the remains of dead plants and animals
Where did the nitrogen come from?
- produced by volcanoes
Where did the water vapour go?
- condensed to form oceans
Pollutants
- carbon monoxide: poisonous (blocks blood from carrying oxygen)
- incomplete combustion
- particulates: global dimming
- incomplete combustion
- sulfur dioxide and nitrogen oxides: cause acid rain and breathing problems
- nitrogen and oxygen react together near car engines as the temperature being high enough to start a reaction
- sulfur is released when burning fuels, and it reacts with oxygen in the air
Incomplete combustion
- burning something without enough oxygen
Greenhouse effect
- greenhouse gases in the atmosphere
- the Earth absorbs radiation from the Sun and reflects some
- the greenhouse gases are absorbing it and keeping the Earth warm
- higher temperatures
- ice caps melting
- changing habitats
Life cycle assessment
- assesses te environmental impact of all stages of a product
- extracting and processing raw materials, manufacturing and packaging, use of product, disposal (including transport and distribution at each stage)