Precipitation (rain, vapours) mixed with acidic chemicals of the atmosphere lower the pH of rainwater and thus cause acid rain. Acid rain is hazardous for the life on the earth.
what are the primary causes and effects of acid rain?
Burning of coal, gas automobile exhaust and other industrial processes release sulphur dioxide and nitrogen oxides in the air. These gases when mixed with the atmospheric moisture and cause acid rain. Acid rain contains sulfuric acid or nitric acid. Lightning during rain also produces nitric oxides which add to rain acid.
Atmospheric industrial pollutants are the main cause of acid rain. Acid rain is damaging forests, plants and agriculture, raising the acid level in lakes and ponds, killing fish and aquatic life and damaging human health.
The most prominent dispute between the USA and Canada s due to acid rain. Canada claims that somehow US industrial pollutants are drifting to Canada and are causing acid rain in Canada. This acid rain has made many Canadian lakes acidic and caused killing of fish and disorders of the ecological system. Similarly, the killing of fish by acid rain has been reported by Norway, Sweden and the northeastern United States.
Pure acid rain has pH of about 5.6. this is because the rain combines with the carbon dioxide in the air. Carbon dioxide is a waste product of burning and other life processes. Water and carbon dioxide from an acid rain carbonic acid. But pollutants make the water more acidic. In the last 25 years the average pH of the rain in the northeastern United States has dropped to 4.1. on occasions the pH has been as low as 3.
Acid rain is commonly found in large cities, areas of large population and in the industrialized area. This is because these areas usually have more air pollution. But wind can carry pollutant far from their source. Thus acid rain can fall in any area of the country or world.
Besides the health hazard of many forms of life, acids rain causes many other problems. It corrodes or wears away, metal, painted surfaces, and even stone buildings and monuments. Sculptures built in Germany as early as 1702 showed no corrosion in 1908 photographs. Photographs taken in 1969 showed noticeable corrosion.
As the energy crisis continues, more and more coal is burned for energy. So the problem of air pollution continues to become more serious. Some environmentalists believe that acid rain would continue to be a major environmental problem for many years to come.