The accumulation of acids or acidic compounds on the surface of the Earth, in lakes or streams, or on objects or vegetation near the Earth’s surface, as a result of their separation from the atmosphere. Acid deposition can harm the environment in a variety of ways, as by causing the acidification of lakes and streams, the leaching of minerals and other nutrients from soil, and the inhibition of nitrogen fixation and photosynthesis in plants. ◇ The accumulation of acids that fall to the Earth dissolved in water is known as wet deposition. Wet deposition includes all forms of acid precipitation such as acid rain, snow, and fog. ◇ The accumulation of acidic particles that settle out of the atmosphere or of acidic gases that are absorbed by plant tissues or other surfaces is known as dry deposition.
Our Living Language : Acid deposition—usually referred to simply as acid rain—actually includes two forms of pollution, wet and dry. When fossil fuels such as coal, gasoline, and oil are burned, they release the gases sulfur dioxide and nitrogen oxide. In the wet type of acid deposition, these compounds combine with water vapor in the atmosphere to form highly corrosive sulfuric and nitric acids. Prevailing winds carry the acids away from the industrial areas where they originate, and they fall to earth as rain, snow, or fog. In the dry type, the prevailing winds deposit acidic gases and particulate matter on objects in the open such as buildings, vehicles, and trees. When rain washes away this acidic matter, the runoff is even more acidic than the rainwater. Acid deposition is a serious environmental problem in parts of the world with a high density of factories, power plants, and automobiles, including much of the United States and Canada, as well as areas of Europe and Asia. It harms forests and soils and pollutes lakes and rivers, killing fish and other aquatic life. It also affects human health, contributing to respiratory diseases such as asthma and emphysema. Many scientists believe that some environmental damage caused by acid deposition could take years, even decades or centuries, to repair. Acid deposition can also damage historic buildings and monuments by corroding the stone and metal of which they are constructed. Individual and societal efforts to reduce acid deposition involve many interrelated social, economic, and political factors.
- Acid drop
a tart candy, as a sourball. Historical Examples The acid drop is at this moment watching the team for all she’s worth. A Patriotic Schoolgirl Angela Brazil He sat beside me, facing the q-b, and offered us an acid drop. Sea and Sardinia D. H. Lawrence He gave his Mother a kiss, and often when […]
- Acid dust
air-polluting particles of dust, usually wind-borne, having high concentrations of acid.
- Acid dye
any of a class of dyes containing one or more acidic groups, as the sulfo group: used in acid solution chiefly for dyeing wool and silk. Historical Examples If there is a precipitate there is a basic dye, if not, an acid dye. The Manufacture of Paper Robert Walter Sindall The goods may advantageously be […]
- Acid etching
noun a technique for engraving blown or cast glass or a metal by the use of an acidic substance; esp. the use of hydrofluoric acid to etch a pattern onto a glass or metal surface Examples Acid etching craft kits are now available, making the process simple and fun. Word Origin by 1873 Historical Examples […]
resistant to decolorizing by acidified alcohol after staining. Historical Examples The acid-fast bacteria are particularly rich in fatty substances, especially the higher wax-like fats. The Fundamentals of Bacteriology Charles Bradfield Morrey Other bacteria than the acid-fast group are stained blue by Gabbet’s method. A Manual of Clinical Diagnosis James Campbell Todd This method is supposed […]