Acid Rain Eric Meuli ESS 315 What is Acid Rain? Acid Rain is the result of air born pollutants, mainly NO and SO2, entering the atmosphere and reacting with water, oxygen, and other chemicals to form various acidic compounds Natural Sources Volcanoes and decaying vegetation make up a small percentage of these gases NO SO2 NO Human Sources The burning of Fossil Fuels, such as coal and oil, release vast amounts of these pollutants into our atmosphere SO2 NO SO2 NO Where? In the United States acid rain is at it’s lowest pH values predominantly in the industrial region. Where? (cont) Acid rain has become a major trans-boundary environmental issue for European countries in the late twentieth century. Soil’s Buffering Capacity Unless it falls directly into a stream or lake, rain must first pass through soil. In some cases the soil is able to reduce the acidity of the water due to its buffering capacity. The greater the buffering capacity, the greater the quantity of acid or base that must be incorporated to alter the pH. Cation Exchange? Not so Good. Good! How Does Acid Rain Affect Fish and Other Aquatic Organisms? • Tolerance to water acidity varies from one case to the next. • Generally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels some adult fish begin to die. Everything’s Connected Plants and animals in the same ecosystem are very interdependent. For example: Frogs may be able to withstand an acidity level of pH 4, but if their primary food source is Mayflies then they too will begin to die off if the pH drops to pH 5. Direct Effect on Humans Acid rain isn’t going to kill you. In fact walking in acid rain or swimming in an acid lake is no more dangerous than walking in normal rain or swimming in a normal lake. Direct Effect on Humans What will harm you are the pollutants that cause acid rain, SO2 and NO. These gases form fine sulfate and nitrate particles that can travel vast distances by wind and they can be inhaled deep into a person’s lungs. High levels of these particles have been associated with increased illness and premature death from lung and heart disorders. SO2 SO2 NO NO Solution The U.S. has been regulating the emissions of SO2 and NO since the adoption of the Clean Air Act, which includes an Acid Rain Program. The goal is that by lowering the output of these gases from coal burning power plants the incidence and severity of these health problems will subside. When fully implemented by the year 2010, the public health benefits of the Acid Rain Program are estimated to be valued at $50 billion annually, due to decreased mortality, hospital admissions, and emergency room visits. References • "Acid Rain." United States Environmental Protection Agency. 8 June 2007. 1 Mar. 2008 <http://epa.gov/>. • "Acid rain in Europe." UNEP/GRID-Arendal Maps and Graphics Library. Jan 98. UNEP/GRID-Arendal. 6 Mar 2008 <http://maps.grida.no/go/graphic/acid_rain_in_europe>. • Kasica, Amy F. "Many Factors Influence Lime Application Rate." Something to Grow On. 15 Apr. 1996. Cornell University. 1 Mar. 2008 <http://www.hort.cornell.edu>. • Watson, John. "What is Acid Rain." USGS. 21 July 1997. 1 Mar. 2008 <http://pubs.usgs.gov/>.