Acid Rain :: Free Essay Writer

  Ã‚  Ã‚  Ã‚  Ã‚  Acid rain is a form of precipitation that contains high levels of sulfuric or nitric acids. In simple terms, acid rain is hail, rain, snow, or sleet that is more acidic than normal. Precipitation naturally is a little acidic but when the pH level drops below a set standard it is acid rain. In general, acid rain is a very complicated problem that is caused by many factors. In this paper, I will discuss how emissions caused by humans effect pH level in precipitation.   Ã‚  Ã‚  Ã‚  Ã‚  First, I will define, in detail, what acid rain is. Acid rain is precipitation that has a pH less than 5.6. The pH scale is a scale that measures if a compound is acidic, basic, or neutral. Neutral is in the middle which has a pH of 7. Basic has a pH between 7.1 and 14 and acidic has a pH between 6.9 and 0. For example, vinegar is acidic with a pH reading of 2.4. Normal precipitation has a pH between 6.9 and 5.9.   Ã‚  Ã‚  Ã‚  Ã‚  Acid rain is formed when sulfur dioxide and various nitrogen oxides combine with atmospheric moisture. Sulfur dioxide is produced by the emissions of electric utilities, industrial companies, commercial and residential heating, smelters and diesel engines. Sulfur dioxide produces sulfuric acid, which will produce acid rain. Nitrogen oxides are produced mostly by transportation (cars, trucks, planes, etc.). Nitrogen oxides produce nitric acid, which will also produce acid rain. The main contributor to acid rain is sulfur oxides (SO2 and SO3). Sulfur oxides are produced naturally but not in the concentration that humans produce. The burning of fossil fuels, such as coal, can be largely blamed for the production of sulfur oxides. The process of acid rain starts when photons from the sun hit ozone molecules (O3) to form oxygen (O2). Next, the O2 molecules react with water (H2O) to form a negatively charged hydroxyl radicals (OH-). It is the hydroxyl radicals that are responsible for oxidizing sulfur dioxide. This will produce sulfuric acid. Oxidation occurs in clouds mostly above cities with heavily polluted air. These clouds contain ammonia and ozone that can catalyze the reaction. This means that the ammonia and ozone will produce more sulfuric acid fast and the ammonia and ozone will not be consumed in the reaction. Nitrogen oxides are produce from power plants and exhaust fumes from automobiles. The reactions to make nitric acid are similar to the reactions to make sulfuric acid.