Acid Rain

{
  "id": "MLC-T-ENV-000282",
  "term": "Acid Rain",
  "field": "Environment",
  "definition": "1. Acid rain is a term used to describe several ways that acidic compounds fall out of the atmosphere, causing a variety of ground-level environmental effects. These effects include damage to forests and soils, fish and other living things, and human health. Acid rain also reduces how clearly we can see through the air, an effect called visibility reduction. Sulfur dioxide and nitrogen oxides are the primary causes of acid rain. In the United States, about two-thirds of all sulfur dioxide and one-quarter of all nitrogen oxides come from electric power generation that relies on burning fossil fuels like coal. Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. These acidic compounds fall to the earth as acidic rain, fog, and snow, or as dry deposited gases and particles that can be blown to the ground by the wind. In fact, prevailing winds can blow the compounds that cause acid rain across state and national borders, and sometimes over hundreds of miles.\n\n2. The result of sulfur dioxide (SO2) and nitrogen oxides (NOx) reacting in the atmosphere with water and returning to earth as rain, fog, or snow. For more information, visit EPA's Acid Rain Web site.\n\n3. Precipitation which has been rendered (made) acidic by airborne pollutants.\n\n4. Natural rainfall that contains nitric and sulfuric acids due to nitrogen oxide (NOx) and sulfur dioxide discharged into the air by industries, power plants, automobiles and other emission sources.\n\n5. The result of sulfur dioxide (SO2) and nitrogen oxides (NOx) reacting in the atmosphere with water and returning to earth as rain, fog, or snow. Broadly used to include both wet and dry deposition. The acid rain page (http://www.epa.gov/acidrain/index.html) provides a great deal of information about this issue.\n\n6. Air pollution produced when acid chemicals are incorporated into rain, snow, fog, or mist. The \"acid\" in acid rain comes from sulfur oxides and nitrogen oxides, products of burning coal and other fuels from certain industrial processes. The sulfur oxides and nitrogen oxides are related to two strong acids: sulfuric acid and nitric acid. When sulfur dioxide and nitrogen oxides are released from power plants and other sources, winds blow them far from their source. If the acid chemicals in the air are blown into areas where the weather is wet, the acids can fall to the Earth in the rain, snow, fog, or mist. In areas where the weather is dry, the acid chemicals may become incorporated into dusts or smokes. Acid rain can damage the environment, human health, and property. EPA Website (http://www.epa.gov/acidrain/).\n\n7. Rainwater that has an acidity content greater than the postulated natural pH of about 5.6. It is formed when sulfur dioxides and nitrogen oxides, as gases or fine particles in the atmosphere, combine with water vapor and precipitate as sulfuric acid or nitric acid in rain, snow, or fog. The dry forms are acidic gases or particulates. See acid deposition.\n\n8. Rainwater that has an acidity content greater than the postulated natural pH of about 5.6. It is formed when sulfur dioxides and nitrogen oxides, as gases or fine particles in the atmosphere, combine with water vapor and precipitate as sulfuric acid or nitric acid in rain, snow, or fog. The dry forms are acidic gases or particulates.\n\n9. Acids form when certain atmospheric gases (primarily carbon dioxide, sulfur dioxide, and nitrogen oxides) come in contact with water in the atmosphere or on the ground and are chemically converted to acidic substances. Oxidants play a major role in several of these acid-forming processes. Carbon dioxide dissolved in rain is converted to a weak acid (carbonic acid). Other gases, primarily oxides of sulfur and nitrogen, are converted to strong acids (sulfuric and nitric acids). Although rain is naturally slightly acidic because of carbon dioxide, natural emissions of sulfur and nitrogen oxides, and certain organic acids, human activities can make it much more acidic. Occasional pH readings of well below 2.4 (the acidity of vinegar) have been reported in industrialized areas. The principal natural phenomena that contribute acid-producing gases to the atmosphere are emissions from volcanoes and from biological processes that occur on the land, in wetlands, and in the oceans. The effects of acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe. Principal human sources are industrial and power-generating plants and transportation vehicles. The gases may be carried hundreds of miles in the atmosphere before they are converted to acids and deposited.\n\n10. Result of sulfur dioxide (SO2) and nitrogen oxides (NOx) reacting in the atmosphere with water and returning to earth as rain, fog, or snow. Broadly used to include both wet and dry deposition.",
  "subject": "Air",
  "references": [
    "Clean Energy Glossary",
    "Greening EPA Glossary",
    "Drinking Water Technical & Legal Terms",
    "Chesapeake Bay Glossary",
    "Acid Rain Glossary",
    "Air Permitting Terms",
    "Greenhouse Gas Emissions",
    "Greenhouse Emissions Glossary",
    "NASA Earth Observatory Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/acid-rain/"
}