Learn about greenhouse gases, global warming, air pollution & water pollution
The Earth is surrounded by a layer called the atmosphere. Air is a mixture of gases.
Greenhouse gases trap heat in the atmosphere, keeping Earth warm. The two main ones are:
| Gas | Sources |
|---|---|
| 🌫️ Carbon Dioxide (CO₂) | Burning fossil fuels, deforestation |
| 🐄 Methane (CH₄) | Cattle, landfills, decay of plants/animals |
Global Warming = increase in Earth's average temperature due to more greenhouse gases.
Causes of Global Warming:
Effects of Global Warming:
Measures to combat climate change:
| Pollutant | Source | Effect | Reduction |
|---|---|---|---|
| 💨 Carbon Monoxide (CO) | Incomplete combustion | Binds to haemoglobin → death | Catalytic converters |
| 🌋 Sulfur Dioxide (SO₂) | Burning fossil fuels, volcanoes | Acid rain, respiratory problems | Limestone scrubbers |
| 🚗 Oxides of Nitrogen | Car engines, lightning | Acid rain, lung damage | Catalytic converters |
| ❄️ CFCs | Refrigerators, sprays | Depletes ozone layer → UV rays | Replace with safer chemicals |
| 💭 Smoke | Fires, factories, vehicles | Lung damage, suffocation | Regular vehicle servicing |
Water pollution occurs when harmful substances enter water bodies.
| Cause | Effect |
|---|---|
| 🚽 Sewage | Harmful bacteria, kills fish |
| 🌾 Excess fertilisers | Eutrophication → fish die |
| 🏭 Industrial wastes | Toxic metals, dyes, acids |
| 🛢️ Oil spillage | Harms marine life, seabirds |
| 🛍️ Garbage/plastic | Kills aquatic animals |
How to prevent water pollution:
Test what you've learnt! Pick the best answer for each question.