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Stratosphere
- 10-50 km above sea level
- Short wave UV radiation breaks down oxygen molecules and O atoms combine with O2 to form O3. Halogens under UV radiation also break down, negatively affecting the ozone formation dynamic equilibrium.
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Troposphere
- 0-10 km above sea level
- Tropospheric ozone is a pollutant as a result of pollution by volatile organic compounds, Co2 and CO, SO2 and NO. It is a secondary pollutant which forms in the presence of sunlight.
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What are the effects of tropospheric ozone?
- Damages forests and leaves, photosynthetic ability
- Harms lung tissue
- Damages fabric and rubber materials
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Where is photochemical smog more likely to occur?
- High pressure zone
- High use of fossil fuels
- Low-lying areas
- Large populations (many cars)
- Cold weather (more use of fossil fuels and cold air sinks)
- Deforestation
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What are the possible causes of the rise of temperatures?
- Industrialization and the use of fossil fuels, rice patty farming, cattle farming
- Sunspot activity
- Deforestation ‘volcanic activity
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What is the composition of the atmosphere?
It’s mostly oxygen and nitrogen with trace amounts of other gases such as CO2, argon and water vapor.
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Where is ozone in the atmosphere?
Between 25 and 35 km, which protects the surface from UV radiation.
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What are the layers of the atmosphere?
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
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What is meant by an ozone hole?
An area of reduced concentration of ozone in the stratosphere caused by aerosols such as CFC.
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What are the negative effects of UV radiation on life forms?
- Humans: cataracts, skin cancer
- Animals: damage photosynthetic organisms, especially phytoplankton, which are crucial to aquatic food webs.
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How do we deal with ozone layer depletion?
- Replace ODSs with HFCs.
- Collect and recycle CFC containing refrigerators.
- Replace halogen containing pesticides with non-chemical alternatives such as crop rotation.
- Montreal Protocol in 1987 included the complete phasing out of ODSs by 2040. Many developing countries have followed suit. However, illegal trade continues. Despite the banning of the production of all CFCs in 2010, one seems to be rising at an alarming rate. Its source is unknown. Australia, having felt the effects early on, has national legislation and replaced CFC with HFC, which is a greenhouse gas.
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What is the difference between wet and dry deposition
- Dry deposition: Oxides fall directly to the ground as dry particles (ash).
- Wet deposition: Oxides are oxidized to form acid, which can be carried for thousands of kilometres.
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Sources of freshwater pollution
- Run-off
- Sewage
- Sdw
- Industrial discharge
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Sources of marine pollution
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