Acid Rain - GCSE Biology Definition

Acid rain is rainwater that has become more acidic than normal due to the presence of dissolved gases such as sulphur dioxide (SO₂) and nitrogen oxides (NOₓ). These gases are released into the air by burning fossil fuels in vehicles, factories, and power stations. In the atmosphere, they react with water vapour to form dilute sulphuric and nitric acids, which fall to the ground as acid rain. Acid rain can lower the pH of soils and water bodies, harming plants and aquatic life. It can also damage buildings and monuments made from limestone. Understanding acid rain helps show GCSE Biology students how pollution from human activities can affect ecosystems.