Acid Rain.

What Causes Acid Rain? One of the main causes of acid rain is sulfur dioxide. Natural sources, which emit this gas, are Volcanoes, sea spray, rotting vegetation and plankton. However, the burning of fossil fuels, such as Coal and oil, are largely to be blamed for approximately half of the emissions of this gas in the world. When sulfur dioxide reaches the atmosphere, it oxidizes to first form a sulfate ion. It then becomes sulfuric acid as it joins with hydrogen atoms in the air and falls back down to earth. Oxidation occurs the most in clouds and especially in heavily polluted air where o…