What causes acid rain?
Two common air pollutants acidify rain: sulphur dioxide (SO2) and nitrogen oxides (NOX)
These acid gases are made in a number of ways :
- Burning fossil fuels in a power station
- Burning petrol and diesel in forms of transport.
- Natural geological processes such as volcanoes.
When these substances are released into the atmosphere, they can be carried over long distances by prevailing winds and return to earth as acidic rain, snow or fog.
The higher the concentration of these gases then the lower (more acidic) the pH will be.