Acid Rain

6 Pages 1450 Words

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 other compounds such as ammonia and the ozone help to catalyze the reaction, changing more sulfur dioxide to sulfuric acid. The following pages will show the effects of acid rain on: Trees and Soils, Lakes and Aquatic Systems, Materials, Atmosphere, Architecture and Humans.
One of the most serious impacts of acid precipitation is on forests and soils. Great damage is done when sulfuric acid falls onto the earth as rain. Nutrients present in the soils are washed away. Aluminum also present in the soil is freed and the roots of trees absorb this toxic element. Thus, the trees are starved to death as they are deprived of their vital nutrients such as calcium and magnesium. Not the entire sulphur dioxide is converted to sulfuric acid. In fact, a substantial amount can float into the atmosphere, move over to another area and return to the soils unconverted. As this gas returns to earth, it clogs up the stomata in the leaves, thus hindering photosynthesis. Research has been made where red spruce seedlings were sprayed with different combinations of sulfuric and nitric acid of pH ranging from 2.5 to 4.5. The needles of these seedlings were observed to develop brown lesions. Eventually, the needles fall off. It was also found that new needles grew more slowly at higher concentrations of acid used. Because the rate at which the needles were falling was greater than the rate at whic...