2.91 - Atmospheric Pollution

What is an air pollutant

A substance present in air that can cause harm to humans and the environment

In what forms can pollutants be

• Solid particles

• Liquid droplets

• Gases

Can be natural or man-made

What is a greenhouse gas

A gas that absorbs heat in the atmosphere and prevents heat from escaping, keeping the Earth warmer

Name 3 properties of carbon dioxide

• Colourless

• Odourless

• Non-toxic greenhouse gas

Name 6 processes that produce carbon dioxide

• Volcanic eruptions

• Respiration of animals

• Burning or decay of organic matter

• Burning of fossil fuels

• From complete combustion reactions

• From the industrial production of cement

What causes the fluctuations of CO2 in the atmosphere between summer and winter

Seasonal variations in photosynthesis

What are two things that can reduce CO2 levels

• Tropical rainforests (being destroyed) → absorb CO2

• Oceans → dissolve CO2

Apart form CO2, what are 6 other greenhouse gases

• Methane (CH4)

• Nitrous oxide (N2O)

• Water vapour (H2O)

• Ozone (O3)

• CFCs

• HFC’s

Explain the greenhouse effect and how greenhouse gases affect the planet

1. Sunlight (short infrared waves) reaches Earth and warms the surface.

2. Earth radiates heat back as longer infrared waves.

3. These longer waves cannot pass freely through the atmosphere.

4. Greenhouse gases (like CO₂ and water vapour) absorb and re-emit some of this heat.

5. This traps heat in the atmosphere, warming the Earth — this is called the greenhouse effect.

What does an increase in greenhouse gases cause

Global warming

What does global warming cause

1. Polar ice caps to melt and sea levels to rise.

2. Low-lying areas of land would submerge under the sea.

3. A change in climate and weather patterns all over the world. Extreme weather events such as hurricanes and cyclones would be more frequent. Tropical areas are experiencing more frequent and destructive storms and floods.

4. Some agricultural areas will cease to produce crops and become deserts due to climate change.

5. Some species that cannot adapt with a change in climate will die out.

How can we lower the levels of carbon dioxide

• Less consumption of fossil fuels.

• Using renewable sources of energy.

• Reduce reliance on cars.

• More energy efficient buildings.

• Improved power plant efficiency.

• Planting more trees.

• The Kyoto Protocol (1997) is the world's primary international agreement on combating global warming. 100 countries committed to reduce their emissions of COz and five other greenhouse gases.

• The UN climate change conference to discuss the way forward on many issues including curbing COz production.