Natural acid rain

From GeoClasses

Natural acid rain

Although carbon dioxide (CO₂) makes up only 0.04% of the atmosphere, it can dissolve into rainwater to produce a weak acid (carbonic acid - H₂CO₃). This acidity is enough however, to cause substantial chemical weathering of minerals over geologic time.

Anthropogenic acid rain

Human activities, such as the burning of fossil fuels like coal, can increase the acidity of rain because many fossil fuels have a significant sulfur content. When this sulfur is burnt it oxidises to become sulfur dioxide gas (SO₂) which can react with rain water to produce a stronger acid (sulfuric acid - H₂SO₄). This accelerates weathering, and can result in increased leaching of heavy metals into streams.

Other sources of acidity

• Plants - water seeping through the soil can dissolve organic acids from plant material. This is why if you wish to increase the acidity of the soil in your garden you can add plant matter, such as peat or pine needles to the soil.