Science: Section 5
Pollution and the Environment
Poor air quality not only harms our health, it can also harm the environment. The main adverse effects are acid rain, nutrient enrichment and the greenhouse effect.
When we burn fossil fuels such as petrol and coal they release gases containing nitrogen and in some cases sulfur into the air. These gases are carried up high into the air and can be blown by the wind over other countries a great distance away. Once in the air, the gases dissolve in water in the atmosphere and are changed into chemicals called acids.
When it rains these chemicals fall back to earth. This is called acid rain. The chemicals are deposited in rivers, on land and on buildings, and over time they can cause problems. Some of the air pollution produced in the UK can end up in countries in northern Europe including Sweden, Norway and Denmark.
Acid rain can cause many problems such as:
- Corrosion of iron bridges
- Corrosion of limestone buildings
- Damage to plants and the soil they grow in
- Damages wildlife especially fish
The good news is that new laws have been brought in to reduce the emissions of sulphur which has led to a big reduction in acid rain. However emissions of nitrogen are reducing much more slowly and it may take some decades for the soil and water environments to recover.
Click here to show the Acid Rain Experiment Video
Nutrient Enrichment
Nutrients are the things that all living things need in order to grow and nourish. Plants require the 3 essential nutrients, nitrogen, potassium and phosphorus to grow however too much of any one of these nutrients can be harmful.
Nitrogen released into the air from burning fuels can cause an excess of nutrients in soil and water.
In soil, nutrient enrichment can cause some plants such as grass to grow well, but others to grow less well. The plants that grow however can eventually stop the other plants from growing at all.
In water, nutrient enrichment can lead to the growth of microorganisms such as algae. These microorganisms can use up the oxygen in the water and stop sunlight getting to the plants that live there. This can be harmful to both plants and fish in the water that need the oxygen to breathe.
Greenhouse effect
Carbon Dioxide
Carbon dioxide is produced when any hydrocarbon burns completely in air. It contributes to the greenhouse effect which leads to global warming. Global warming can change the weather causing glaciers to melt and making sea levels rise. It can cause drought and floods in some places and affect people, plants and animals.
There is also a Homework Sheet you can download that supports and develops further the ideas from this section.
