**3.4 Acid rain**

Acid rain primarily caused by Sulfur dioxide (SO2), oxides of nitrogen and ozone to some extent. Acid rain is caused when pollutants present in the air mixes up with the rain and fall back on the ground. Sulfuric and nitric acid solutions cause acidity in rainwater. Acid rain decreases the pH of the soil, causing its acidity to increase, which decreases the level of important nutrients found in the soil [4]. Soils low in cation exchange capacity and base saturation are the most sensitive to acid precipitation [5].
